+
36 Audio Filters
+
+
When you configure your FFmpeg build, you can disable any of the
+existing filters using --disable-filters.
+The configure output will show the audio filters included in your
+build.
+
+
Below is a description of the currently available audio filters.
+
+
+
+
36.1 acompressor
+
+
A compressor is mainly used to reduce the dynamic range of a signal.
+Especially modern music is mostly compressed at a high ratio to
+improve the overall loudness. It’s done to get the highest attention
+of a listener, "fatten" the sound and bring more "power" to the track.
+If a signal is compressed too much it may sound dull or "dead"
+afterwards or it may start to "pump" (which could be a powerful effect
+but can also destroy a track completely).
+The right compression is the key to reach a professional sound and is
+the high art of mixing and mastering. Because of its complex settings
+it may take a long time to get the right feeling for this kind of effect.
+
+
Compression is done by detecting the volume above a chosen level
+threshold and dividing it by the factor set with ratio.
+So if you set the threshold to -12dB and your signal reaches -6dB a ratio
+of 2:1 will result in a signal at -9dB. Because an exact manipulation of
+the signal would cause distortion of the waveform the reduction can be
+levelled over the time. This is done by setting "Attack" and "Release".
+attack determines how long the signal has to rise above the threshold
+before any reduction will occur and release sets the time the signal
+has to fall below the threshold to reduce the reduction again. Shorter signals
+than the chosen attack time will be left untouched.
+The overall reduction of the signal can be made up afterwards with the
+makeup setting. So compressing the peaks of a signal about 6dB and
+raising the makeup to this level results in a signal twice as loud than the
+source. To gain a softer entry in the compression the knee flattens the
+hard edge at the threshold in the range of the chosen decibels.
+
+
The filter accepts the following options:
+
+
+- level_in
+Set input gain. Default is 1. Range is between 0.015625 and 64.
+
+- mode
+Set mode of compressor operation. Can be upward or downward.
+Default is downward.
+
+- threshold
+If a signal of stream rises above this level it will affect the gain
+reduction.
+By default it is 0.125. Range is between 0.00097563 and 1.
+
+- ratio
+Set a ratio by which the signal is reduced. 1:2 means that if the level
+rose 4dB above the threshold, it will be only 2dB above after the reduction.
+Default is 2. Range is between 1 and 20.
+
+- attack
+Amount of milliseconds the signal has to rise above the threshold before gain
+reduction starts. Default is 20. Range is between 0.01 and 2000.
+
+- release
+Amount of milliseconds the signal has to fall below the threshold before
+reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
+
+- makeup
+Set the amount by how much signal will be amplified after processing.
+Default is 1. Range is from 1 to 64.
+
+- knee
+Curve the sharp knee around the threshold to enter gain reduction more softly.
+Default is 2.82843. Range is between 1 and 8.
+
+- link
+Choose if the average level between all channels of input stream
+or the louder(maximum) channel of input stream affects the
+reduction. Default is average.
+
+- detection
+Should the exact signal be taken in case of peak or an RMS one in case
+of rms. Default is rms which is mostly smoother.
+
+- mix
+How much to use compressed signal in output. Default is 1.
+Range is between 0 and 1.
+
+
+
+
+
36.1.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.2 acontrast
+
Simple audio dynamic range compression/expansion filter.
+
+
The filter accepts the following options:
+
+
+- contrast
+Set contrast. Default is 33. Allowed range is between 0 and 100.
+
+
+
+
+
36.3 acopy
+
+
Copy the input audio source unchanged to the output. This is mainly useful for
+testing purposes.
+
+
+
+
36.4 acrossfade
+
+
Apply cross fade from one input audio stream to another input audio stream.
+The cross fade is applied for specified duration near the end of first stream.
+
+
The filter accepts the following options:
+
+
+- nb_samples, ns
+Specify the number of samples for which the cross fade effect has to last.
+At the end of the cross fade effect the first input audio will be completely
+silent. Default is 44100.
+
+- duration, d
+Specify the duration of the cross fade effect. See
+(ffmpeg-utils)the Time duration section in the ffmpeg-utils(1) manual
+for the accepted syntax.
+By default the duration is determined by nb_samples.
+If set this option is used instead of nb_samples.
+
+- overlap, o
+Should first stream end overlap with second stream start. Default is enabled.
+
+- curve1
+Set curve for cross fade transition for first stream.
+
+- curve2
+Set curve for cross fade transition for second stream.
+
+For description of available curve types see afade filter description.
+
+
+
+
+
36.4.1 Examples
+
+
+- Cross fade from one input to another:
+
+
ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:c1=exp:c2=exp output.flac
+
- Cross fade from one input to another but without overlapping:
+
+
ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:o=0:c1=exp:c2=exp output.flac
+
+
+
+
+
+
36.5 acrossover
+
Split audio stream into several bands.
+
+
This filter splits audio stream into two or more frequency ranges.
+Summing all streams back will give flat output.
+
+
The filter accepts the following options:
+
+
+- split
+Set split frequencies. Those must be positive and increasing.
+
+- order
+Set filter order for each band split. This controls filter roll-off or steepness
+of filter transfer function.
+Available values are:
+
+
+- ‘2nd’
+12 dB per octave.
+
- ‘4th’
+24 dB per octave.
+
- ‘6th’
+36 dB per octave.
+
- ‘8th’
+48 dB per octave.
+
- ‘10th’
+60 dB per octave.
+
- ‘12th’
+72 dB per octave.
+
- ‘14th’
+84 dB per octave.
+
- ‘16th’
+96 dB per octave.
+
- ‘18th’
+108 dB per octave.
+
- ‘20th’
+120 dB per octave.
+
+
+Default is 4th.
+
+- level
+Set input gain level. Allowed range is from 0 to 1. Default value is 1.
+
+- gains
+Set output gain for each band. Default value is 1 for all bands.
+
+- precision
+Set which precision to use when processing samples.
+
+
+- auto
+Auto pick internal sample format depending on other filters.
+
+- float
+Always use single-floating point precision sample format.
+
+- double
+Always use double-floating point precision sample format.
+
+
+Default value is auto.
+
+
+
+
+
36.5.1 Examples
+
+
+- Split input audio stream into two bands (low and high) with split frequency of 1500 Hz,
+each band will be in separate stream:
+
+
ffmpeg -i in.flac -filter_complex 'acrossover=split=1500[LOW][HIGH]' -map '[LOW]' low.wav -map '[HIGH]' high.wav
+
- Same as above, but with higher filter order:
+
+
ffmpeg -i in.flac -filter_complex 'acrossover=split=1500:order=8th[LOW][HIGH]' -map '[LOW]' low.wav -map '[HIGH]' high.wav
+
- Same as above, but also with additional middle band (frequencies between 1500 and 8000):
+
+
ffmpeg -i in.flac -filter_complex 'acrossover=split=1500 8000:order=8th[LOW][MID][HIGH]' -map '[LOW]' low.wav -map '[MID]' mid.wav -map '[HIGH]' high.wav
+
+
+
+
+
+
36.6 acrusher
+
+
Reduce audio bit resolution.
+
+
This filter is bit crusher with enhanced functionality. A bit crusher
+is used to audibly reduce number of bits an audio signal is sampled
+with. This doesn’t change the bit depth at all, it just produces the
+effect. Material reduced in bit depth sounds more harsh and "digital".
+This filter is able to even round to continuous values instead of discrete
+bit depths.
+Additionally it has a D/C offset which results in different crushing of
+the lower and the upper half of the signal.
+An Anti-Aliasing setting is able to produce "softer" crushing sounds.
+
+
Another feature of this filter is the logarithmic mode.
+This setting switches from linear distances between bits to logarithmic ones.
+The result is a much more "natural" sounding crusher which doesn’t gate low
+signals for example. The human ear has a logarithmic perception,
+so this kind of crushing is much more pleasant.
+Logarithmic crushing is also able to get anti-aliased.
+
+
The filter accepts the following options:
+
+
+- level_in
+Set level in.
+
+- level_out
+Set level out.
+
+- bits
+Set bit reduction.
+
+- mix
+Set mixing amount.
+
+- mode
+Can be linear: lin or logarithmic: log.
+
+- dc
+Set DC.
+
+- aa
+Set anti-aliasing.
+
+- samples
+Set sample reduction.
+
+- lfo
+Enable LFO. By default disabled.
+
+- lforange
+Set LFO range.
+
+- lforate
+Set LFO rate.
+
+
+
+
+
36.6.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.7 acue
+
+
Delay audio filtering until a given wallclock timestamp. See the cue
+filter.
+
+
+
+
36.8 adeclick
+
Remove impulsive noise from input audio.
+
+
Samples detected as impulsive noise are replaced by interpolated samples using
+autoregressive modelling.
+
+
+- window, w
+Set window size, in milliseconds. Allowed range is from 10 to
+100. Default value is 55 milliseconds.
+This sets size of window which will be processed at once.
+
+- overlap, o
+Set window overlap, in percentage of window size. Allowed range is from
+50 to 95. Default value is 75 percent.
+Setting this to a very high value increases impulsive noise removal but makes
+whole process much slower.
+
+- arorder, a
+Set autoregression order, in percentage of window size. Allowed range is from
+0 to 25. Default value is 2 percent. This option also
+controls quality of interpolated samples using neighbour good samples.
+
+- threshold, t
+Set threshold value. Allowed range is from 1 to 100.
+Default value is 2.
+This controls the strength of impulsive noise which is going to be removed.
+The lower value, the more samples will be detected as impulsive noise.
+
+- burst, b
+Set burst fusion, in percentage of window size. Allowed range is 0 to
+10. Default value is 2.
+If any two samples detected as noise are spaced less than this value then any
+sample between those two samples will be also detected as noise.
+
+- method, m
+Set overlap method.
+
+It accepts the following values:
+
+- add, a
+Select overlap-add method. Even not interpolated samples are slightly
+changed with this method.
+
+- save, s
+Select overlap-save method. Not interpolated samples remain unchanged.
+
+
+Default value is a.
+
+
+
+
+
36.9 adeclip
+
Remove clipped samples from input audio.
+
+
Samples detected as clipped are replaced by interpolated samples using
+autoregressive modelling.
+
+
+- window, w
+Set window size, in milliseconds. Allowed range is from 10 to 100.
+Default value is 55 milliseconds.
+This sets size of window which will be processed at once.
+
+- overlap, o
+Set window overlap, in percentage of window size. Allowed range is from 50
+to 95. Default value is 75 percent.
+
+- arorder, a
+Set autoregression order, in percentage of window size. Allowed range is from
+0 to 25. Default value is 8 percent. This option also controls
+quality of interpolated samples using neighbour good samples.
+
+- threshold, t
+Set threshold value. Allowed range is from 1 to 100.
+Default value is 10. Higher values make clip detection less aggressive.
+
+- hsize, n
+Set size of histogram used to detect clips. Allowed range is from 100 to 9999.
+Default value is 1000. Higher values make clip detection less aggressive.
+
+- method, m
+Set overlap method.
+
+It accepts the following values:
+
+- add, a
+Select overlap-add method. Even not interpolated samples are slightly changed
+with this method.
+
+- save, s
+Select overlap-save method. Not interpolated samples remain unchanged.
+
+
+Default value is a.
+
+
+
+
+
36.10 adecorrelate
+
Apply decorrelation to input audio stream.
+
+
The filter accepts the following options:
+
+
+- stages
+Set decorrelation stages of filtering. Allowed
+range is from 1 to 16. Default value is 6.
+
+- seed
+Set random seed used for setting delay in samples across channels.
+
+
+
+
+
36.11 adelay
+
+
Delay one or more audio channels.
+
+
Samples in delayed channel are filled with silence.
+
+
The filter accepts the following option:
+
+
+- delays
+Set list of delays in milliseconds for each channel separated by ’|’.
+Unused delays will be silently ignored. If number of given delays is
+smaller than number of channels all remaining channels will not be delayed.
+If you want to delay exact number of samples, append ’S’ to number.
+If you want instead to delay in seconds, append ’s’ to number.
+
+- all
+Use last set delay for all remaining channels. By default is disabled.
+This option if enabled changes how option delays is interpreted.
+
+
+
+
+
36.11.1 Examples
+
+
+- Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
+the second channel (and any other channels that may be present) unchanged.
+
+
+
- Delay second channel by 500 samples, the third channel by 700 samples and leave
+the first channel (and any other channels that may be present) unchanged.
+
+
+
- Delay all channels by same number of samples:
+
+
adelay=delays=64S:all=1
+
+
+
+
+
+
36.12 adenorm
+
Remedy denormals in audio by adding extremely low-level noise.
+
+
This filter shall be placed before any filter that can produce denormals.
+
+
A description of the accepted parameters follows.
+
+
+- level
+Set level of added noise in dB. Default is -351.
+Allowed range is from -451 to -90.
+
+- type
+Set type of added noise.
+
+
+- dc
+Add DC signal.
+
- ac
+Add AC signal.
+
- square
+Add square signal.
+
- pulse
+Add pulse signal.
+
+
+Default is dc.
+
+
+
+
+
36.12.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.13 aderivative, aintegral
+
+
Compute derivative/integral of audio stream.
+
+
Applying both filters one after another produces original audio.
+
+
+
+
36.14 adrc
+
+
Apply spectral dynamic range controller filter to input audio stream.
+
+
A description of the accepted options follows.
+
+
+- transfer
+Set the transfer expression.
+
+The expression can contain the following constants:
+
+
+- ch
+current channel number
+
+- sn
+current sample number
+
+- nb_channels
+number of channels
+
+- t
+timestamp expressed in seconds
+
+- sr
+sample rate
+
+- p
+current frequency power value, in dB
+
+- f
+current frequency in Hz
+
+
+Default value is p.
+
+- attack
+Set the attack in milliseconds. Default is 50 milliseconds.
+Allowed range is from 1 to 1000 milliseconds.
+
- release
+Set the release in milliseconds. Default is 100 milliseconds.
+Allowed range is from 5 to 2000 milliseconds.
+
- channels
+Set which channels to filter, by default all channels in audio stream are filtered.
+
+
+
+
+
36.14.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
36.14.2 Examples
+
+
+- Apply spectral compression to all frequencies with threshold of -50 dB and 1:6 ratio:
+
+
adrc=transfer='if(gt(p,-50),-50+(p-(-50))/6,p)':attack=50:release=100
+
- Similar to above but with 1:2 ratio and filtering only front center channel:
+
+
adrc=transfer='if(gt(p,-50),-50+(p-(-50))/2,p)':attack=50:release=100:channels=FC
+
- Apply spectral noise gate to all frequencies with threshold of -85 dB and with short attack time and short release time:
+
+
adrc=transfer='if(lte(p,-85),p-800,p)':attack=1:release=5
+
- Apply spectral expansion to all frequencies with threshold of -10 dB and 1:2 ratio:
+
+
adrc=transfer='if(lt(p,-10),-10+(p-(-10))*2,p)':attack=50:release=100
+
- Apply limiter to max -60 dB to all frequencies, with attack of 2 ms and release of 10 ms:
+
+
adrc=transfer='min(p,-60)':attack=2:release=10
+
+
+
+
+
+
36.15 adynamicequalizer
+
+
Apply dynamic equalization to input audio stream.
+
+
A description of the accepted options follows.
+
+
+- threshold
+Set the detection threshold used to trigger equalization.
+Threshold detection is using detection filter.
+Default value is 0. Allowed range is from 0 to 100.
+
+- dfrequency
+Set the detection frequency in Hz used for detection filter used to trigger equalization.
+Default value is 1000 Hz. Allowed range is between 2 and 1000000 Hz.
+
+- dqfactor
+Set the detection resonance factor for detection filter used to trigger equalization.
+Default value is 1. Allowed range is from 0.001 to 1000.
+
+- tfrequency
+Set the target frequency of equalization filter.
+Default value is 1000 Hz. Allowed range is between 2 and 1000000 Hz.
+
+- tqfactor
+Set the target resonance factor for target equalization filter.
+Default value is 1. Allowed range is from 0.001 to 1000.
+
+- attack
+Set the amount of milliseconds the signal from detection has to rise above
+the detection threshold before equalization starts.
+Default is 20. Allowed range is between 1 and 2000.
+
+- release
+Set the amount of milliseconds the signal from detection has to fall below the
+detection threshold before equalization ends.
+Default is 200. Allowed range is between 1 and 2000.
+
+- ratio
+Set the ratio by which the equalization gain is raised.
+Default is 1. Allowed range is between 0 and 30.
+
+- makeup
+Set the makeup offset by which the equalization gain is raised.
+Default is 0. Allowed range is between 0 and 100.
+
+- range
+Set the max allowed cut/boost amount. Default is 50.
+Allowed range is from 1 to 200.
+
+- mode
+Set the mode of filter operation, can be one of the following:
+
+
+- ‘listen’
+Output only isolated detection signal.
+
- ‘cut’
+Cut frequencies above detection threshold.
+
- ‘boost’
+Boost frequencies bellow detection threshold.
+
+Default mode is ‘cut’.
+
+- dftype
+Set the type of detection filter, can be one of the following:
+
+
+- ‘bandpass’
+- ‘lowpass’
+- ‘highpass’
+- ‘peak’
+
+Default type is ‘bandpass’.
+
+- tftype
+Set the type of target filter, can be one of the following:
+
+
+- ‘bell’
+- ‘lowshelf’
+- ‘highshelf’
+
+Default type is ‘bell’.
+
+- direction
+Set processing direction relative to threshold.
+
+- ‘downward’
+Boost/Cut if threshold is higher/lower than detected volume.
+
- ‘upward’
+Boost/Cut if threshold is lower/higher than detected volume.
+
+Default direction is ‘downward’.
+
+- auto
+Automatically gather threshold from detection filter. By default
+is ‘disabled’.
+This option is useful to detect threshold in certain time frame of
+input audio stream, in such case option value is changed at runtime.
+
+Available values are:
+
+- ‘disabled’
+Disable using automatically gathered threshold value.
+
- ‘off’
+Stop picking threshold value.
+
- ‘on’
+Start picking threshold value.
+
+
+- precision
+Set which precision to use when processing samples.
+
+
+- auto
+Auto pick internal sample format depending on other filters.
+
+- float
+Always use single-floating point precision sample format.
+
+- double
+Always use double-floating point precision sample format.
+
+
+
+
+
+
36.15.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.16 adynamicsmooth
+
+
Apply dynamic smoothing to input audio stream.
+
+
A description of the accepted options follows.
+
+
+- sensitivity
+Set an amount of sensitivity to frequency fluctations. Default is 2.
+Allowed range is from 0 to 1e+06.
+
+- basefreq
+Set a base frequency for smoothing. Default value is 22050.
+Allowed range is from 2 to 1e+06.
+
+
+
+
+
36.16.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.17 aecho
+
+
Apply echoing to the input audio.
+
+
Echoes are reflected sound and can occur naturally amongst mountains
+(and sometimes large buildings) when talking or shouting; digital echo
+effects emulate this behaviour and are often used to help fill out the
+sound of a single instrument or vocal. The time difference between the
+original signal and the reflection is the delay, and the
+loudness of the reflected signal is the decay.
+Multiple echoes can have different delays and decays.
+
+
A description of the accepted parameters follows.
+
+
+- in_gain
+Set input gain of reflected signal. Default is 0.6.
+
+- out_gain
+Set output gain of reflected signal. Default is 0.3.
+
+- delays
+Set list of time intervals in milliseconds between original signal and reflections
+separated by ’|’. Allowed range for each delay is (0 - 90000.0].
+Default is 1000.
+
+- decays
+Set list of loudness of reflected signals separated by ’|’.
+Allowed range for each decay is (0 - 1.0].
+Default is 0.5.
+
+
+
+
+
36.17.1 Examples
+
+
+- Make it sound as if there are twice as many instruments as are actually playing:
+
+
+
- If delay is very short, then it sounds like a (metallic) robot playing music:
+
+
+
- A longer delay will sound like an open air concert in the mountains:
+
+
aecho=0.8:0.9:1000:0.3
+
- Same as above but with one more mountain:
+
+
aecho=0.8:0.9:1000|1800:0.3|0.25
+
+
+
+
+
+
36.18 aemphasis
+
Audio emphasis filter creates or restores material directly taken from LPs or
+emphased CDs with different filter curves. E.g. to store music on vinyl the
+signal has to be altered by a filter first to even out the disadvantages of
+this recording medium.
+Once the material is played back the inverse filter has to be applied to
+restore the distortion of the frequency response.
+
+
The filter accepts the following options:
+
+
+- level_in
+Set input gain.
+
+- level_out
+Set output gain.
+
+- mode
+Set filter mode. For restoring material use reproduction mode, otherwise
+use production mode. Default is reproduction mode.
+
+- type
+Set filter type. Selects medium. Can be one of the following:
+
+
+- col
+select Columbia.
+
- emi
+select EMI.
+
- bsi
+select BSI (78RPM).
+
- riaa
+select RIAA.
+
- cd
+select Compact Disc (CD).
+
- 50fm
+select 50µs (FM).
+
- 75fm
+select 75µs (FM).
+
- 50kf
+select 50µs (FM-KF).
+
- 75kf
+select 75µs (FM-KF).
+
+
+
+
+
+
36.18.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.19 aeval
+
+
Modify an audio signal according to the specified expressions.
+
+
This filter accepts one or more expressions (one for each channel),
+which are evaluated and used to modify a corresponding audio signal.
+
+
It accepts the following parameters:
+
+
+- exprs
+Set the ’|’-separated expressions list for each separate channel. If
+the number of input channels is greater than the number of
+expressions, the last specified expression is used for the remaining
+output channels.
+
+- channel_layout, c
+Set output channel layout. If not specified, the channel layout is
+specified by the number of expressions. If set to ‘same’, it will
+use by default the same input channel layout.
+
+
+
Each expression in exprs can contain the following constants and functions:
+
+
+- ch
+channel number of the current expression
+
+- n
+number of the evaluated sample, starting from 0
+
+- s
+sample rate
+
+- t
+time of the evaluated sample expressed in seconds
+
+- nb_in_channels
+- nb_out_channels
+input and output number of channels
+
+- val(CH)
+the value of input channel with number CH
+
+
+
Note: this filter is slow. For faster processing you should use a
+dedicated filter.
+
+
+
+
36.19.1 Examples
+
+
+- Half volume:
+
+
aeval=val(ch)/2:c=same
+
- Invert phase of the second channel:
+
+
+
+
+
+
+
36.20 aexciter
+
+
An exciter is used to produce high sound that is not present in the
+original signal. This is done by creating harmonic distortions of the
+signal which are restricted in range and added to the original signal.
+An Exciter raises the upper end of an audio signal without simply raising
+the higher frequencies like an equalizer would do to create a more
+"crisp" or "brilliant" sound.
+
+
The filter accepts the following options:
+
+
+- level_in
+Set input level prior processing of signal.
+Allowed range is from 0 to 64.
+Default value is 1.
+
+- level_out
+Set output level after processing of signal.
+Allowed range is from 0 to 64.
+Default value is 1.
+
+- amount
+Set the amount of harmonics added to original signal.
+Allowed range is from 0 to 64.
+Default value is 1.
+
+- drive
+Set the amount of newly created harmonics.
+Allowed range is from 0.1 to 10.
+Default value is 8.5.
+
+- blend
+Set the octave of newly created harmonics.
+Allowed range is from -10 to 10.
+Default value is 0.
+
+- freq
+Set the lower frequency limit of producing harmonics in Hz.
+Allowed range is from 2000 to 12000 Hz.
+Default is 7500 Hz.
+
+- ceil
+Set the upper frequency limit of producing harmonics.
+Allowed range is from 9999 to 20000 Hz.
+If value is lower than 10000 Hz no limit is applied.
+
+- listen
+Mute the original signal and output only added harmonics.
+By default is disabled.
+
+
+
+
+
36.20.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.21 afade
+
+
Apply fade-in/out effect to input audio.
+
+
A description of the accepted parameters follows.
+
+
+- type, t
+Specify the effect type, can be either in for fade-in, or
+out for a fade-out effect. Default is in.
+
+- start_sample, ss
+Specify the number of the start sample for starting to apply the fade
+effect. Default is 0.
+
+- nb_samples, ns
+Specify the number of samples for which the fade effect has to last. At
+the end of the fade-in effect the output audio will have the same
+volume as the input audio, at the end of the fade-out transition
+the output audio will be silence. Default is 44100.
+
+- start_time, st
+Specify the start time of the fade effect. Default is 0.
+The value must be specified as a time duration; see
+(ffmpeg-utils)the Time duration section in the ffmpeg-utils(1) manual
+for the accepted syntax.
+If set this option is used instead of start_sample.
+
+- duration, d
+Specify the duration of the fade effect. See
+(ffmpeg-utils)the Time duration section in the ffmpeg-utils(1) manual
+for the accepted syntax.
+At the end of the fade-in effect the output audio will have the same
+volume as the input audio, at the end of the fade-out transition
+the output audio will be silence.
+By default the duration is determined by nb_samples.
+If set this option is used instead of nb_samples.
+
+- curve
+Set curve for fade transition.
+
+It accepts the following values:
+
+- tri
+select triangular, linear slope (default)
+
- qsin
+select quarter of sine wave
+
- hsin
+select half of sine wave
+
- esin
+select exponential sine wave
+
- log
+select logarithmic
+
- ipar
+select inverted parabola
+
- qua
+select quadratic
+
- cub
+select cubic
+
- squ
+select square root
+
- cbr
+select cubic root
+
- par
+select parabola
+
- exp
+select exponential
+
- iqsin
+select inverted quarter of sine wave
+
- ihsin
+select inverted half of sine wave
+
- dese
+select double-exponential seat
+
- desi
+select double-exponential sigmoid
+
- losi
+select logistic sigmoid
+
- sinc
+select sine cardinal function
+
- isinc
+select inverted sine cardinal function
+
- nofade
+no fade applied
+
+
+- silence
+Set the initial gain for fade-in or final gain for fade-out.
+Default value is 0.0.
+
+- unity
+Set the initial gain for fade-out or final gain for fade-in.
+Default value is 1.0.
+
+
+
+
+
36.21.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
36.21.2 Examples
+
+
+- Fade in first 15 seconds of audio:
+
+
+
- Fade out last 25 seconds of a 900 seconds audio:
+
+
afade=t=out:st=875:d=25
+
+
+
+
+
+
36.22 afftdn
+
Denoise audio samples with FFT.
+
+
A description of the accepted parameters follows.
+
+
+- noise_reduction, nr
+Set the noise reduction in dB, allowed range is 0.01 to 97.
+Default value is 12 dB.
+
+- noise_floor, nf
+Set the noise floor in dB, allowed range is -80 to -20.
+Default value is -50 dB.
+
+- noise_type, nt
+Set the noise type.
+
+It accepts the following values:
+
+- white, w
+Select white noise.
+
+- vinyl, v
+Select vinyl noise.
+
+- shellac, s
+Select shellac noise.
+
+- custom, c
+Select custom noise, defined in bn option.
+
+Default value is white noise.
+
+
+- band_noise, bn
+Set custom band noise profile for every one of 15 bands.
+Bands are separated by ’ ’ or ’|’.
+
+- residual_floor, rf
+Set the residual floor in dB, allowed range is -80 to -20.
+Default value is -38 dB.
+
+- track_noise, tn
+Enable noise floor tracking. By default is disabled.
+With this enabled, noise floor is automatically adjusted.
+
+- track_residual, tr
+Enable residual tracking. By default is disabled.
+
+- output_mode, om
+Set the output mode.
+
+It accepts the following values:
+
+- input, i
+Pass input unchanged.
+
+- output, o
+Pass noise filtered out.
+
+- noise, n
+Pass only noise.
+
+Default value is output.
+
+
+- adaptivity, ad
+Set the adaptivity factor, used how fast to adapt gains adjustments per
+each frequency bin. Value 0 enables instant adaptation, while higher values
+react much slower.
+Allowed range is from 0 to 1. Default value is 0.5.
+
+- floor_offset, fo
+Set the noise floor offset factor. This option is used to adjust offset applied to measured
+noise floor. It is only effective when noise floor tracking is enabled.
+Allowed range is from -2.0 to 2.0. Default value is 1.0.
+
+- noise_link, nl
+Set the noise link used for multichannel audio.
+
+It accepts the following values:
+
+- none
+Use unchanged channel’s noise floor.
+
+- min
+Use measured min noise floor of all channels.
+
+- max
+Use measured max noise floor of all channels.
+
+- average
+Use measured average noise floor of all channels.
+
+Default value is min.
+
+
+- band_multiplier, bm
+Set the band multiplier factor, used how much to spread bands across frequency bins.
+Allowed range is from 0.2 to 5. Default value is 1.25.
+
+- sample_noise, sn
+Toggle capturing and measurement of noise profile from input audio.
+
+It accepts the following values:
+
+- start, begin
+Start sample noise capture.
+
+- stop, end
+Stop sample noise capture and measure new noise band profile.
+
+Default value is none.
+
+
+- gain_smooth, gs
+Set gain smooth spatial radius, used to smooth gains applied to each frequency bin.
+Useful to reduce random music noise artefacts.
+Higher values increases smoothing of gains.
+Allowed range is from 0 to 50.
+Default value is 0.
+
+
+
+
+
36.22.1 Commands
+
+
This filter supports the some above mentioned options as commands.
+
+
+
+
36.22.2 Examples
+
+
+- Reduce white noise by 10dB, and use previously measured noise floor of -40dB:
+
+
+
- Reduce white noise by 10dB, also set initial noise floor to -80dB and enable automatic
+tracking of noise floor so noise floor will gradually change during processing:
+
+
afftdn=nr=10:nf=-80:tn=1
+
- Reduce noise by 20dB, using noise floor of -40dB and using commands to take noise profile
+of first 0.4 seconds of input audio:
+
+
asendcmd=0.0 afftdn sn start,asendcmd=0.4 afftdn sn stop,afftdn=nr=20:nf=-40
+
+
+
+
+
+
36.23 afftfilt
+
Apply arbitrary expressions to samples in frequency domain.
+
+
+- real
+Set frequency domain real expression for each separate channel separated
+by ’|’. Default is "re".
+If the number of input channels is greater than the number of
+expressions, the last specified expression is used for the remaining
+output channels.
+
+- imag
+Set frequency domain imaginary expression for each separate channel
+separated by ’|’. Default is "im".
+
+Each expression in real and imag can contain the following
+constants and functions:
+
+
+- sr
+sample rate
+
+- b
+current frequency bin number
+
+- nb
+number of available bins
+
+- ch
+channel number of the current expression
+
+- chs
+number of channels
+
+- pts
+current frame pts
+
+- re
+current real part of frequency bin of current channel
+
+- im
+current imaginary part of frequency bin of current channel
+
+- real(b, ch)
+Return the value of real part of frequency bin at location (bin,channel)
+
+- imag(b, ch)
+Return the value of imaginary part of frequency bin at location (bin,channel)
+
+
+- win_size
+Set window size. Allowed range is from 16 to 131072.
+Default is 4096
+
+- win_func
+Set window function.
+
+It accepts the following values:
+
+- ‘rect’
+- ‘bartlett’
+- ‘hann, hanning’
+- ‘hamming’
+- ‘blackman’
+- ‘welch’
+- ‘flattop’
+- ‘bharris’
+- ‘bnuttall’
+- ‘bhann’
+- ‘sine’
+- ‘nuttall’
+- ‘lanczos’
+- ‘gauss’
+- ‘tukey’
+- ‘dolph’
+- ‘cauchy’
+- ‘parzen’
+- ‘poisson’
+- ‘bohman’
+- ‘kaiser’
+
+Default is hann.
+
+- overlap
+Set window overlap. If set to 1, the recommended overlap for selected
+window function will be picked. Default is 0.75.
+
+
+
+
+
36.23.1 Examples
+
+
+- Leave almost only low frequencies in audio:
+
+
afftfilt="'real=re * (1-clip((b/nb)*b,0,1))':imag='im * (1-clip((b/nb)*b,0,1))'"
+
- Apply robotize effect:
+
+
afftfilt="real='hypot(re,im)*sin(0)':imag='hypot(re,im)*cos(0)':win_size=512:overlap=0.75"
+
- Apply whisper effect:
+
+
afftfilt="real='hypot(re,im)*cos((random(0)*2-1)*2*3.14)':imag='hypot(re,im)*sin((random(1)*2-1)*2*3.14)':win_size=128:overlap=0.8"
+
- Apply phase shift:
+
+
afftfilt="real=re*cos(1)-im*sin(1):imag=re*sin(1)+im*cos(1)"
+
+
+
+
+
+
36.24 afir
+
+
Apply an arbitrary Finite Impulse Response filter.
+
+
This filter is designed for applying long FIR filters,
+up to 60 seconds long.
+
+
It can be used as component for digital crossover filters,
+room equalization, cross talk cancellation, wavefield synthesis,
+auralization, ambiophonics, ambisonics and spatialization.
+
+
This filter uses the streams higher than first one as FIR coefficients.
+If the non-first stream holds a single channel, it will be used
+for all input channels in the first stream, otherwise
+the number of channels in the non-first stream must be same as
+the number of channels in the first stream.
+
+
It accepts the following parameters:
+
+
+- dry
+Set dry gain. This sets input gain.
+
+- wet
+Set wet gain. This sets final output gain.
+
+- length
+Set Impulse Response filter length. Default is 1, which means whole IR is processed.
+
+- gtype
+Enable applying gain measured from power of IR.
+
+Set which approach to use for auto gain measurement.
+
+
+- none
+Do not apply any gain.
+
+- peak
+select peak gain, very conservative approach. This is default value.
+
+- dc
+select DC gain, limited application.
+
+- gn
+select gain to noise approach, this is most popular one.
+
+- ac
+select AC gain.
+
+- rms
+select RMS gain.
+
+
+- irgain
+Set gain to be applied to IR coefficients before filtering.
+Allowed range is 0 to 1. This gain is applied after any gain applied with gtype option.
+
+- irfmt
+Set format of IR stream. Can be mono or input.
+Default is input.
+
+- maxir
+Set max allowed Impulse Response filter duration in seconds. Default is 30 seconds.
+Allowed range is 0.1 to 60 seconds.
+
+- response
+Show IR frequency response, magnitude(magenta), phase(green) and group delay(yellow) in additional video stream.
+By default it is disabled.
+
+- channel
+Set for which IR channel to display frequency response. By default is first channel
+displayed. This option is used only when response is enabled.
+
+- size
+Set video stream size. This option is used only when response is enabled.
+
+- rate
+Set video stream frame rate. This option is used only when response is enabled.
+
+- minp
+Set minimal partition size used for convolution. Default is 8192.
+Allowed range is from 1 to 65536.
+Lower values decreases latency at cost of higher CPU usage.
+
+- maxp
+Set maximal partition size used for convolution. Default is 8192.
+Allowed range is from 8 to 65536.
+Lower values may increase CPU usage.
+
+- nbirs
+Set number of input impulse responses streams which will be switchable at runtime.
+Allowed range is from 1 to 32. Default is 1.
+
+- ir
+Set IR stream which will be used for convolution, starting from 0, should always be
+lower than supplied value by nbirs option. Default is 0.
+This option can be changed at runtime via commands.
+
+- precision
+Set which precision to use when processing samples.
+
+
+- auto
+Auto pick internal sample format depending on other filters.
+
+- float
+Always use single-floating point precision sample format.
+
+- double
+Always use double-floating point precision sample format.
+
+
+Default value is auto.
+
+- irload
+Set when to load IR stream. Can be init or access.
+First one load and prepares all IRs on initialization, second one
+once on first access of specific IR.
+Default is init.
+
+
+
+
+
36.24.1 Examples
+
+
+- Apply reverb to stream using mono IR file as second input, complete command using ffmpeg:
+
+
ffmpeg -i input.wav -i middle_tunnel_1way_mono.wav -lavfi afir output.wav
+
- Apply true stereo processing given input stereo stream, and two stereo impulse responses for left and right channel,
+the impulse response files are files with names l_ir.wav and r_ir.wav:
+
+
"pan=4C|c0=FL|c1=FL|c2=FR|c3=FR[a];amovie=l_ir.wav[LIR];amovie=r_ir.wav[RIR];[LIR][RIR]amerge[ir];[a][ir]afir=irfmt=input:gtype=gn:irgain=-5dB,pan=stereo|FL<c0+c2|FR<c1+c3"
+
+
+
+
+
+
+
36.26 afreqshift
+
Apply frequency shift to input audio samples.
+
+
The filter accepts the following options:
+
+
+- shift
+Specify frequency shift. Allowed range is -INT_MAX to INT_MAX.
+Default value is 0.0.
+
+- level
+Set output gain applied to final output. Allowed range is from 0.0 to 1.0.
+Default value is 1.0.
+
+- order
+Set filter order used for filtering. Allowed range is from 1 to 16.
+Default value is 8.
+
+
+
+
+
36.26.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.27 afwtdn
+
Reduce broadband noise from input samples using Wavelets.
+
+
A description of the accepted options follows.
+
+
+- sigma
+Set the noise sigma, allowed range is from 0 to 1.
+Default value is 0.
+This option controls strength of denoising applied to input samples.
+Most useful way to set this option is via decibels, eg. -45dB.
+
+- levels
+Set the number of wavelet levels of decomposition.
+Allowed range is from 1 to 12.
+Default value is 10.
+Setting this too low make denoising performance very poor.
+
+- wavet
+Set wavelet type for decomposition of input frame.
+They are sorted by number of coefficients, from lowest to highest.
+More coefficients means worse filtering speed, but overall better quality.
+Available wavelets are:
+
+
+- ‘sym2’
+- ‘sym4’
+- ‘rbior68’
+- ‘deb10’
+- ‘sym10’
+- ‘coif5’
+- ‘bl3’
+
+
+- percent
+Set percent of full denoising. Allowed range is from 0 to 100 percent.
+Default value is 85 percent or partial denoising.
+
+- profile
+If enabled, first input frame will be used as noise profile.
+If first frame samples contain non-noise performance will be very poor.
+
+- adaptive
+If enabled, input frames are analyzed for presence of noise.
+If noise is detected with high possibility then input frame profile will be
+used for processing following frames, until new noise frame is detected.
+
+- samples
+Set size of single frame in number of samples. Allowed range is from 512 to
+65536. Default frame size is 8192 samples.
+
+- softness
+Set softness applied inside thresholding function. Allowed range is from 0 to
+10. Default softness is 1.
+
+
+
+
+
36.27.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.28 agate
+
+
A gate is mainly used to reduce lower parts of a signal. This kind of signal
+processing reduces disturbing noise between useful signals.
+
+
Gating is done by detecting the volume below a chosen level threshold
+and dividing it by the factor set with ratio. The bottom of the noise
+floor is set via range. Because an exact manipulation of the signal
+would cause distortion of the waveform the reduction can be levelled over
+time. This is done by setting attack and release.
+
+
attack determines how long the signal has to fall below the threshold
+before any reduction will occur and release sets the time the signal
+has to rise above the threshold to reduce the reduction again.
+Shorter signals than the chosen attack time will be left untouched.
+
+
+- level_in
+Set input level before filtering.
+Default is 1. Allowed range is from 0.015625 to 64.
+
+- mode
+Set the mode of operation. Can be upward or downward.
+Default is downward. If set to upward mode, higher parts of signal
+will be amplified, expanding dynamic range in upward direction.
+Otherwise, in case of downward lower parts of signal will be reduced.
+
+- range
+Set the level of gain reduction when the signal is below the threshold.
+Default is 0.06125. Allowed range is from 0 to 1.
+Setting this to 0 disables reduction and then filter behaves like expander.
+
+- threshold
+If a signal rises above this level the gain reduction is released.
+Default is 0.125. Allowed range is from 0 to 1.
+
+- ratio
+Set a ratio by which the signal is reduced.
+Default is 2. Allowed range is from 1 to 9000.
+
+- attack
+Amount of milliseconds the signal has to rise above the threshold before gain
+reduction stops.
+Default is 20 milliseconds. Allowed range is from 0.01 to 9000.
+
+- release
+Amount of milliseconds the signal has to fall below the threshold before the
+reduction is increased again. Default is 250 milliseconds.
+Allowed range is from 0.01 to 9000.
+
+- makeup
+Set amount of amplification of signal after processing.
+Default is 1. Allowed range is from 1 to 64.
+
+- knee
+Curve the sharp knee around the threshold to enter gain reduction more softly.
+Default is 2.828427125. Allowed range is from 1 to 8.
+
+- detection
+Choose if exact signal should be taken for detection or an RMS like one.
+Default is rms. Can be peak or rms.
+
+- link
+Choose if the average level between all channels or the louder channel affects
+the reduction.
+Default is average. Can be average or maximum.
+
+
+
+
+
36.28.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.29 aiir
+
+
Apply an arbitrary Infinite Impulse Response filter.
+
+
It accepts the following parameters:
+
+
+- zeros, z
+Set B/numerator/zeros/reflection coefficients.
+
+- poles, p
+Set A/denominator/poles/ladder coefficients.
+
+- gains, k
+Set channels gains.
+
+- dry_gain
+Set input gain.
+
+- wet_gain
+Set output gain.
+
+- format, f
+Set coefficients format.
+
+
+- ‘ll’
+lattice-ladder function
+
- ‘sf’
+analog transfer function
+
- ‘tf’
+digital transfer function
+
- ‘zp’
+Z-plane zeros/poles, cartesian (default)
+
- ‘pr’
+Z-plane zeros/poles, polar radians
+
- ‘pd’
+Z-plane zeros/poles, polar degrees
+
- ‘sp’
+S-plane zeros/poles
+
+
+- process, r
+Set type of processing.
+
+
+- ‘d’
+direct processing
+
- ‘s’
+serial processing
+
- ‘p’
+parallel processing
+
+
+- precision, e
+Set filtering precision.
+
+
+- ‘dbl’
+double-precision floating-point (default)
+
- ‘flt’
+single-precision floating-point
+
- ‘i32’
+32-bit integers
+
- ‘i16’
+16-bit integers
+
+
+- normalize, n
+Normalize filter coefficients, by default is enabled.
+Enabling it will normalize magnitude response at DC to 0dB.
+
+- mix
+How much to use filtered signal in output. Default is 1.
+Range is between 0 and 1.
+
+- response
+Show IR frequency response, magnitude(magenta), phase(green) and group delay(yellow) in additional video stream.
+By default it is disabled.
+
+- channel
+Set for which IR channel to display frequency response. By default is first channel
+displayed. This option is used only when response is enabled.
+
+- size
+Set video stream size. This option is used only when response is enabled.
+
+
+
Coefficients in tf and sf format are separated by spaces and are in ascending
+order.
+
+
Coefficients in zp format are separated by spaces and order of coefficients
+doesn’t matter. Coefficients in zp format are complex numbers with i
+imaginary unit.
+
+
Different coefficients and gains can be provided for every channel, in such case
+use ’|’ to separate coefficients or gains. Last provided coefficients will be
+used for all remaining channels.
+
+
+
+
36.29.1 Examples
+
+
+- Apply 2 pole elliptic notch at around 5000Hz for 48000 Hz sample rate:
+
+
aiir=k=1:z=7.957584807809675810E-1 -2.575128568908332300 3.674839853930788710 -2.57512875289799137 7.957586296317130880E-1:p=1 -2.86950072432325953 3.63022088054647218 -2.28075678147272232 6.361362326477423500E-1:f=tf:r=d
+
- Same as above but in
zp format:
+
+
aiir=k=0.79575848078096756:z=0.80918701+0.58773007i 0.80918701-0.58773007i 0.80884700+0.58784055i 0.80884700-0.58784055i:p=0.63892345+0.59951235i 0.63892345-0.59951235i 0.79582691+0.44198673i 0.79582691-0.44198673i:f=zp:r=s
+
- Apply 3-rd order analog normalized Butterworth low-pass filter, using analog transfer function format:
+
+
aiir=z=1.3057 0 0 0:p=1.3057 2.3892 2.1860 1:f=sf:r=d
+
+
+
+
+
+
36.30 alimiter
+
+
The limiter prevents an input signal from rising over a desired threshold.
+This limiter uses lookahead technology to prevent your signal from distorting.
+It means that there is a small delay after the signal is processed. Keep in mind
+that the delay it produces is the attack time you set.
+
+
The filter accepts the following options:
+
+
+- level_in
+Set input gain. Default is 1.
+
+- level_out
+Set output gain. Default is 1.
+
+- limit
+Don’t let signals above this level pass the limiter. Default is 1.
+
+- attack
+The limiter will reach its attenuation level in this amount of time in
+milliseconds. Default is 5 milliseconds.
+
+- release
+Come back from limiting to attenuation 1.0 in this amount of milliseconds.
+Default is 50 milliseconds.
+
+- asc
+When gain reduction is always needed ASC takes care of releasing to an
+average reduction level rather than reaching a reduction of 0 in the release
+time.
+
+- asc_level
+Select how much the release time is affected by ASC, 0 means nearly no changes
+in release time while 1 produces higher release times.
+
+- level
+Auto level output signal. Default is enabled.
+This normalizes audio back to 0dB if enabled.
+
+- latency
+Compensate the delay introduced by using the lookahead buffer set with attack
+parameter. Also flush the valid audio data in the lookahead buffer when the
+stream hits EOF.
+
+
+
Depending on picked setting it is recommended to upsample input 2x or 4x times
+with aresample before applying this filter.
+
+
+
+
36.31 allpass
+
+
Apply a two-pole all-pass filter with central frequency (in Hz)
+frequency, and filter-width width.
+An all-pass filter changes the audio’s frequency to phase relationship
+without changing its frequency to amplitude relationship.
+
+
The filter accepts the following options:
+
+
+- frequency, f
+Set frequency in Hz.
+
+- width_type, t
+Set method to specify band-width of filter.
+
+- h
+Hz
+
- q
+Q-Factor
+
- o
+octave
+
- s
+slope
+
- k
+kHz
+
+
+- width, w
+Specify the band-width of a filter in width_type units.
+
+- mix, m
+How much to use filtered signal in output. Default is 1.
+Range is between 0 and 1.
+
+- channels, c
+Specify which channels to filter, by default all available are filtered.
+
+- normalize, n
+Normalize biquad coefficients, by default is disabled.
+Enabling it will normalize magnitude response at DC to 0dB.
+
+- order, o
+Set the filter order, can be 1 or 2. Default is 2.
+
+- transform, a
+Set transform type of IIR filter.
+
+- di
+- dii
+- tdi
+- tdii
+- latt
+- svf
+- zdf
+
+
+- precision, r
+Set precison of filtering.
+
+- auto
+Pick automatic sample format depending on surround filters.
+
- s16
+Always use signed 16-bit.
+
- s32
+Always use signed 32-bit.
+
- f32
+Always use float 32-bit.
+
- f64
+Always use float 64-bit.
+
+
+
+
+
+
36.31.1 Commands
+
+
This filter supports the following commands:
+
+- frequency, f
+Change allpass frequency.
+Syntax for the command is : "frequency"
+
+- width_type, t
+Change allpass width_type.
+Syntax for the command is : "width_type"
+
+- width, w
+Change allpass width.
+Syntax for the command is : "width"
+
+- mix, m
+Change allpass mix.
+Syntax for the command is : "mix"
+
+
+
+
+
+
36.32 aloop
+
+
Loop audio samples.
+
+
The filter accepts the following options:
+
+
+- loop
+Set the number of loops. Setting this value to -1 will result in infinite loops.
+Default is 0.
+
+- size
+Set maximal number of samples. Default is 0.
+
+- start
+Set first sample of loop. Default is 0.
+
+- time
+Set the time of loop start in seconds.
+Only used if option named start is set to -1.
+
+
+
+
+
36.33 amerge
+
+
Merge two or more audio streams into a single multi-channel stream.
+
+
The filter accepts the following options:
+
+
+- inputs
+Set the number of inputs. Default is 2.
+
+
+
+
If the channel layouts of the inputs are disjoint, and therefore compatible,
+the channel layout of the output will be set accordingly and the channels
+will be reordered as necessary. If the channel layouts of the inputs are not
+disjoint, the output will have all the channels of the first input then all
+the channels of the second input, in that order, and the channel layout of
+the output will be the default value corresponding to the total number of
+channels.
+
+
For example, if the first input is in 2.1 (FL+FR+LF) and the second input
+is FC+BL+BR, then the output will be in 5.1, with the channels in the
+following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
+first input, b1 is the first channel of the second input).
+
+
On the other hand, if both input are in stereo, the output channels will be
+in the default order: a1, a2, b1, b2, and the channel layout will be
+arbitrarily set to 4.0, which may or may not be the expected value.
+
+
All inputs must have the same sample rate, and format.
+
+
If inputs do not have the same duration, the output will stop with the
+shortest.
+
+
+
+
36.33.1 Examples
+
+
+- Merge two mono files into a stereo stream:
+
+
amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
+
- Multiple merges assuming 1 video stream and 6 audio streams in input.mkv:
+
+
ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv
+
+
+
+
+
+
36.34 amix
+
+
Mixes multiple audio inputs into a single output.
+
+
Note that this filter only supports float samples (the amerge
+and pan audio filters support many formats). If the amix
+input has integer samples then aresample will be automatically
+inserted to perform the conversion to float samples.
+
+
It accepts the following parameters:
+
+- inputs
+The number of inputs. If unspecified, it defaults to 2.
+
+- duration
+How to determine the end-of-stream.
+
+- longest
+The duration of the longest input. (default)
+
+- shortest
+The duration of the shortest input.
+
+- first
+The duration of the first input.
+
+
+
+- dropout_transition
+The transition time, in seconds, for volume renormalization when an input
+stream ends. The default value is 2 seconds.
+
+- weights
+Specify weight of each input audio stream as a sequence of numbers separated
+by a space. If fewer weights are specified compared to number of inputs, the
+last weight is assigned to the remaining inputs.
+Default weight for each input is 1.
+
+- normalize
+Always scale inputs instead of only doing summation of samples.
+Beware of heavy clipping if inputs are not normalized prior or after filtering
+by this filter if this option is disabled. By default is enabled.
+
+
+
+
+
36.34.1 Examples
+
+
+- This will mix 3 input audio streams to a single output with the same duration as the
+first input and a dropout transition time of 3 seconds:
+
+
ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
+
- This will mix one vocal and one music input audio stream to a single output with the same duration as the
+longest input. The music will have quarter the weight as the vocals, and the inputs are not normalized:
+
+
ffmpeg -i VOCALS -i MUSIC -filter_complex amix=inputs=2:duration=longest:dropout_transition=0:weights="1 0.25":normalize=0 OUTPUT
+
+
+
+
+
36.34.2 Commands
+
+
This filter supports the following commands:
+
+- weights
+- normalize
+Syntax is same as option with same name.
+
+
+
+
+
+
36.35 amultiply
+
+
Multiply first audio stream with second audio stream and store result
+in output audio stream. Multiplication is done by multiplying each
+sample from first stream with sample at same position from second stream.
+
+
With this element-wise multiplication one can create amplitude fades and
+amplitude modulations.
+
+
+
+
36.36 anequalizer
+
+
High-order parametric multiband equalizer for each channel.
+
+
It accepts the following parameters:
+
+- params
+-
+
This option string is in format:
+"cchn f=cf w=w g=g t=f | ..."
+Each equalizer band is separated by ’|’.
+
+
+- chn
+Set channel number to which equalization will be applied.
+If input doesn’t have that channel the entry is ignored.
+
+- f
+Set central frequency for band.
+If input doesn’t have that frequency the entry is ignored.
+
+- w
+Set band width in Hertz.
+
+- g
+Set band gain in dB.
+
+- t
+Set filter type for band, optional, can be:
+
+
+- ‘0’
+Butterworth, this is default.
+
+- ‘1’
+Chebyshev type 1.
+
+- ‘2’
+Chebyshev type 2.
+
+
+
+
+- curves
+With this option activated frequency response of anequalizer is displayed
+in video stream.
+
+- size
+Set video stream size. Only useful if curves option is activated.
+
+- mgain
+Set max gain that will be displayed. Only useful if curves option is activated.
+Setting this to a reasonable value makes it possible to display gain which is derived from
+neighbour bands which are too close to each other and thus produce higher gain
+when both are activated.
+
+- fscale
+Set frequency scale used to draw frequency response in video output.
+Can be linear or logarithmic. Default is logarithmic.
+
+- colors
+Set color for each channel curve which is going to be displayed in video stream.
+This is list of color names separated by space or by ’|’.
+Unrecognised or missing colors will be replaced by white color.
+
+
+
+
+
36.36.1 Examples
+
+
+- Lower gain by 10 of central frequency 200Hz and width 100 Hz
+for first 2 channels using Chebyshev type 1 filter:
+
+
anequalizer=c0 f=200 w=100 g=-10 t=1|c1 f=200 w=100 g=-10 t=1
+
+
+
+
+
36.36.2 Commands
+
+
This filter supports the following commands:
+
+- change
+Alter existing filter parameters.
+Syntax for the commands is : "fN|f=freq|w=width|g=gain"
+
+fN is existing filter number, starting from 0, if no such filter is available
+error is returned.
+freq set new frequency parameter.
+width set new width parameter in Hertz.
+gain set new gain parameter in dB.
+
+Full filter invocation with asendcmd may look like this:
+asendcmd=c=’4.0 anequalizer change 0|f=200|w=50|g=1’,anequalizer=...
+
+
+
+
+
+
36.37 anlmdn
+
+
Reduce broadband noise in audio samples using Non-Local Means algorithm.
+
+
Each sample is adjusted by looking for other samples with similar contexts. This
+context similarity is defined by comparing their surrounding patches of size
+p. Patches are searched in an area of r around the sample.
+
+
The filter accepts the following options:
+
+
+- strength, s
+Set denoising strength. Allowed range is from 0.00001 to 10000. Default value is 0.00001.
+
+- patch, p
+Set patch radius duration. Allowed range is from 1 to 100 milliseconds.
+Default value is 2 milliseconds.
+
+- research, r
+Set research radius duration. Allowed range is from 2 to 300 milliseconds.
+Default value is 6 milliseconds.
+
+- output, o
+Set the output mode.
+
+It accepts the following values:
+
+- i
+Pass input unchanged.
+
+- o
+Pass noise filtered out.
+
+- n
+Pass only noise.
+
+Default value is o.
+
+
+- smooth, m
+Set smooth factor. Default value is 11. Allowed range is from 1 to 1000.
+
+
+
+
+
36.37.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.38 anlmf, anlms
+
Apply Normalized Least-Mean-(Squares|Fourth) algorithm to the first audio stream using the second audio stream.
+
+
This adaptive filter is used to mimic a desired filter by finding the filter coefficients that
+relate to producing the least mean square of the error signal (difference between the desired,
+2nd input audio stream and the actual signal, the 1st input audio stream).
+
+
A description of the accepted options follows.
+
+
+- order
+Set filter order.
+
+- mu
+Set filter mu.
+
+- eps
+Set the filter eps.
+
+- leakage
+Set the filter leakage.
+
+- out_mode
+It accepts the following values:
+
+- i
+Pass the 1st input.
+
+- d
+Pass the 2nd input.
+
+- o
+Pass difference between desired, 2nd input and error signal estimate.
+
+- n
+Pass difference between input, 1st input and error signal estimate.
+
+- e
+Pass error signal estimated samples.
+
+Default value is o.
+
+
+
+
+
+
36.38.1 Examples
+
+
+- One of many usages of this filter is noise reduction, input audio is filtered
+with same samples that are delayed by fixed amount, one such example for stereo audio is:
+
+
asplit[a][b],[a]adelay=32S|32S[a],[b][a]anlms=order=128:leakage=0.0005:mu=.5:out_mode=o
+
+
+
+
+
36.38.2 Commands
+
+
This filter supports the same commands as options, excluding option order.
+
+
+
+
+
36.39 anull
+
+
Pass the audio source unchanged to the output.
+
+
+
+
36.40 apad
+
+
Pad the end of an audio stream with silence.
+
+
This can be used together with ffmpeg -shortest to
+extend audio streams to the same length as the video stream.
+
+
A description of the accepted options follows.
+
+
+- packet_size
+Set silence packet size. Default value is 4096.
+
+- pad_len
+Set the number of samples of silence to add to the end. After the
+value is reached, the stream is terminated. This option is mutually
+exclusive with whole_len.
+
+- whole_len
+Set the minimum total number of samples in the output audio stream. If
+the value is longer than the input audio length, silence is added to
+the end, until the value is reached. This option is mutually exclusive
+with pad_len.
+
+- pad_dur
+Specify the duration of samples of silence to add. See
+(ffmpeg-utils)the Time duration section in the ffmpeg-utils(1) manual
+for the accepted syntax. Used only if set to non-negative value.
+
+- whole_dur
+Specify the minimum total duration in the output audio stream. See
+(ffmpeg-utils)the Time duration section in the ffmpeg-utils(1) manual
+for the accepted syntax. Used only if set to non-negative value. If the value is longer than
+the input audio length, silence is added to the end, until the value is reached.
+This option is mutually exclusive with pad_dur
+
+
+
If neither the pad_len nor the whole_len nor pad_dur
+nor whole_dur option is set, the filter will add silence to the end of
+the input stream indefinitely.
+
+
Note that for ffmpeg 4.4 and earlier a zero pad_dur or
+whole_dur also caused the filter to add silence indefinitely.
+
+
+
+
36.40.1 Examples
+
+
+- Add 1024 samples of silence to the end of the input:
+
+
+
- Make sure the audio output will contain at least 10000 samples, pad
+the input with silence if required:
+
+
+
- Use
ffmpeg to pad the audio input with silence, so that the
+video stream will always result the shortest and will be converted
+until the end in the output file when using the shortest
+option:
+
+
ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
+
+
+
+
+
+
36.41 aphaser
+
Add a phasing effect to the input audio.
+
+
A phaser filter creates series of peaks and troughs in the frequency spectrum.
+The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
+
+
A description of the accepted parameters follows.
+
+
+- in_gain
+Set input gain. Default is 0.4.
+
+- out_gain
+Set output gain. Default is 0.74
+
+- delay
+Set delay in milliseconds. Default is 3.0.
+
+- decay
+Set decay. Default is 0.4.
+
+- speed
+Set modulation speed in Hz. Default is 0.5.
+
+- type
+Set modulation type. Default is triangular.
+
+It accepts the following values:
+
+- ‘triangular, t’
+- ‘sinusoidal, s’
+
+
+
+
+
+
36.42 aphaseshift
+
Apply phase shift to input audio samples.
+
+
The filter accepts the following options:
+
+
+- shift
+Specify phase shift. Allowed range is from -1.0 to 1.0.
+Default value is 0.0.
+
+- level
+Set output gain applied to final output. Allowed range is from 0.0 to 1.0.
+Default value is 1.0.
+
+- order
+Set filter order used for filtering. Allowed range is from 1 to 16.
+Default value is 8.
+
+
+
+
+
36.42.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.43 apsyclip
+
Apply Psychoacoustic clipper to input audio stream.
+
+
The filter accepts the following options:
+
+
+- level_in
+Set input gain. By default it is 1. Range is [0.015625 - 64].
+
+- level_out
+Set output gain. By default it is 1. Range is [0.015625 - 64].
+
+- clip
+Set the clipping start value. Default value is 0dBFS or 1.
+
+- diff
+Output only difference samples, useful to hear introduced distortions.
+By default is disabled.
+
+- adaptive
+Set strength of adaptive distortion applied. Default value is 0.5.
+Allowed range is from 0 to 1.
+
+- iterations
+Set number of iterations of psychoacoustic clipper.
+Allowed range is from 1 to 20. Default value is 10.
+
+- level
+Auto level output signal. Default is disabled.
+This normalizes audio back to 0dBFS if enabled.
+
+
+
+
+
36.43.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.44 apulsator
+
+
Audio pulsator is something between an autopanner and a tremolo.
+But it can produce funny stereo effects as well. Pulsator changes the volume
+of the left and right channel based on a LFO (low frequency oscillator) with
+different waveforms and shifted phases.
+This filter have the ability to define an offset between left and right
+channel. An offset of 0 means that both LFO shapes match each other.
+The left and right channel are altered equally - a conventional tremolo.
+An offset of 50% means that the shape of the right channel is exactly shifted
+in phase (or moved backwards about half of the frequency) - pulsator acts as
+an autopanner. At 1 both curves match again. Every setting in between moves the
+phase shift gapless between all stages and produces some "bypassing" sounds with
+sine and triangle waveforms. The more you set the offset near 1 (starting from
+the 0.5) the faster the signal passes from the left to the right speaker.
+
+
The filter accepts the following options:
+
+
+- level_in
+Set input gain. By default it is 1. Range is [0.015625 - 64].
+
+- level_out
+Set output gain. By default it is 1. Range is [0.015625 - 64].
+
+- mode
+Set waveform shape the LFO will use. Can be one of: sine, triangle, square,
+sawup or sawdown. Default is sine.
+
+- amount
+Set modulation. Define how much of original signal is affected by the LFO.
+
+- offset_l
+Set left channel offset. Default is 0. Allowed range is [0 - 1].
+
+- offset_r
+Set right channel offset. Default is 0.5. Allowed range is [0 - 1].
+
+- width
+Set pulse width. Default is 1. Allowed range is [0 - 2].
+
+- timing
+Set possible timing mode. Can be one of: bpm, ms or hz. Default is hz.
+
+- bpm
+Set bpm. Default is 120. Allowed range is [30 - 300]. Only used if timing
+is set to bpm.
+
+- ms
+Set ms. Default is 500. Allowed range is [10 - 2000]. Only used if timing
+is set to ms.
+
+- hz
+Set frequency in Hz. Default is 2. Allowed range is [0.01 - 100]. Only used
+if timing is set to hz.
+
+
+
+
+
36.45 aresample
+
+
Resample the input audio to the specified parameters, using the
+libswresample library. If none are specified then the filter will
+automatically convert between its input and output.
+
+
This filter is also able to stretch/squeeze the audio data to make it match
+the timestamps or to inject silence / cut out audio to make it match the
+timestamps, do a combination of both or do neither.
+
+
The filter accepts the syntax
+[sample_rate:]resampler_options, where sample_rate
+expresses a sample rate and resampler_options is a list of
+key=value pairs, separated by ":". See the
+(ffmpeg-resampler)"Resampler Options" section in the
+ffmpeg-resampler(1) manual
+for the complete list of supported options.
+
+
+
+
36.45.1 Examples
+
+
+- Resample the input audio to 44100Hz:
+
+
+
- Stretch/squeeze samples to the given timestamps, with a maximum of 1000
+samples per second compensation:
+
+
+
+
+
+
+
36.46 areverse
+
+
Reverse an audio clip.
+
+
Warning: This filter requires memory to buffer the entire clip, so trimming
+is suggested.
+
+
+
+
36.46.1 Examples
+
+
+- Take the first 5 seconds of a clip, and reverse it.
+
+
+
+
+
+
+
36.47 arls
+
Apply Recursive Least Squares algorithm to the first audio stream using the second audio stream.
+
+
This adaptive filter is used to mimic a desired filter by recursively finding the filter coefficients that
+relate to producing the minimal weighted linear least squares cost function of the error signal (difference
+between the desired, 2nd input audio stream and the actual signal, the 1st input audio stream).
+
+
A description of the accepted options follows.
+
+
+- order
+Set the filter order.
+
+- lambda
+Set the forgetting factor.
+
+- delta
+Set the coefficient to initialize internal covariance matrix.
+
+- out_mode
+Set the filter output samples. It accepts the following values:
+
+- i
+Pass the 1st input.
+
+- d
+Pass the 2nd input.
+
+- o
+Pass difference between desired, 2nd input and error signal estimate.
+
+- n
+Pass difference between input, 1st input and error signal estimate.
+
+- e
+Pass error signal estimated samples.
+
+Default value is o.
+
+
+
+
+
+
36.48 arnndn
+
+
Reduce noise from speech using Recurrent Neural Networks.
+
+
This filter accepts the following options:
+
+
+- model, m
+Set train model file to load. This option is always required.
+
+- mix
+Set how much to mix filtered samples into final output.
+Allowed range is from -1 to 1. Default value is 1.
+Negative values are special, they set how much to keep filtered noise
+in the final filter output. Set this option to -1 to hear actual
+noise removed from input signal.
+
+
+
+
+
36.48.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.49 asdr
+
Measure Audio Signal-to-Distortion Ratio.
+
+
This filter takes two audio streams for input, and outputs first
+audio stream.
+Results are in dB per channel at end of either input.
+
+
+
+
36.50 asetnsamples
+
+
Set the number of samples per each output audio frame.
+
+
The last output packet may contain a different number of samples, as
+the filter will flush all the remaining samples when the input audio
+signals its end.
+
+
The filter accepts the following options:
+
+
+- nb_out_samples, n
+Set the number of frames per each output audio frame. The number is
+intended as the number of samples per each channel.
+Default value is 1024.
+
+- pad, p
+If set to 1, the filter will pad the last audio frame with zeroes, so
+that the last frame will contain the same number of samples as the
+previous ones. Default value is 1.
+
+
+
For example, to set the number of per-frame samples to 1234 and
+disable padding for the last frame, use:
+
+
asetnsamples=n=1234:p=0
+
+
+
+
+
36.51 asetrate
+
+
Set the sample rate without altering the PCM data.
+This will result in a change of speed and pitch.
+
+
The filter accepts the following options:
+
+
+- sample_rate, r
+Set the output sample rate. Default is 44100 Hz.
+
+
+
+
+
36.52 ashowinfo
+
+
Show a line containing various information for each input audio frame.
+The input audio is not modified.
+
+
The shown line contains a sequence of key/value pairs of the form
+key:value.
+
+
The following values are shown in the output:
+
+
+- n
+The (sequential) number of the input frame, starting from 0.
+
+- pts
+The presentation timestamp of the input frame, in time base units; the time base
+depends on the filter input pad, and is usually 1/sample_rate.
+
+- pts_time
+The presentation timestamp of the input frame in seconds.
+
+- fmt
+The sample format.
+
+- chlayout
+The channel layout.
+
+- rate
+The sample rate for the audio frame.
+
+- nb_samples
+The number of samples (per channel) in the frame.
+
+- checksum
+The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
+audio, the data is treated as if all the planes were concatenated.
+
+- plane_checksums
+A list of Adler-32 checksums for each data plane.
+
+
+
+
+
36.53 asoftclip
+
Apply audio soft clipping.
+
+
Soft clipping is a type of distortion effect where the amplitude of a signal is saturated
+along a smooth curve, rather than the abrupt shape of hard-clipping.
+
+
This filter accepts the following options:
+
+
+- type
+Set type of soft-clipping.
+
+It accepts the following values:
+
+- hard
+- tanh
+- atan
+- cubic
+- exp
+- alg
+- quintic
+- sin
+- erf
+
+
+- threshold
+Set threshold from where to start clipping. Default value is 0dB or 1.
+
+- output
+Set gain applied to output. Default value is 0dB or 1.
+
+- param
+Set additional parameter which controls sigmoid function.
+
+- oversample
+Set oversampling factor.
+
+
+
+
+
36.53.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.54 aspectralstats
+
+
Display frequency domain statistical information about the audio channels.
+Statistics are calculated and stored as metadata for each audio channel and for each audio frame.
+
+
It accepts the following option:
+
+- win_size
+Set the window length in samples. Default value is 2048.
+Allowed range is from 32 to 65536.
+
+- win_func
+Set window function.
+
+It accepts the following values:
+
+- ‘rect’
+- ‘bartlett’
+- ‘hann, hanning’
+- ‘hamming’
+- ‘blackman’
+- ‘welch’
+- ‘flattop’
+- ‘bharris’
+- ‘bnuttall’
+- ‘bhann’
+- ‘sine’
+- ‘nuttall’
+- ‘lanczos’
+- ‘gauss’
+- ‘tukey’
+- ‘dolph’
+- ‘cauchy’
+- ‘parzen’
+- ‘poisson’
+- ‘bohman’
+- ‘kaiser’
+
+Default is hann.
+
+- overlap
+Set window overlap. Allowed range is from 0
+to 1. Default value is 0.5.
+
+- measure
+Select the parameters which are measured. The metadata keys can
+be used as flags, default is all which measures everything.
+none disables all measurement.
+
+
+
A list of each metadata key follows:
+
+
+- mean
+- variance
+- centroid
+- spread
+- skewness
+- kurtosis
+- entropy
+- flatness
+- crest
+- flux
+- slope
+- decrease
+- rolloff
+
+
+
+
+
36.55 asr
+
Automatic Speech Recognition
+
+
This filter uses PocketSphinx for speech recognition. To enable
+compilation of this filter, you need to configure FFmpeg with
+--enable-pocketsphinx.
+
+
It accepts the following options:
+
+
+- rate
+Set sampling rate of input audio. Defaults is 16000.
+This need to match speech models, otherwise one will get poor results.
+
+- hmm
+Set dictionary containing acoustic model files.
+
+- dict
+Set pronunciation dictionary.
+
+- lm
+Set language model file.
+
+- lmctl
+Set language model set.
+
+- lmname
+Set which language model to use.
+
+- logfn
+Set output for log messages.
+
+
+
The filter exports recognized speech as the frame metadata lavfi.asr.text.
+
+
+
+
36.56 astats
+
+
Display time domain statistical information about the audio channels.
+Statistics are calculated and displayed for each audio channel and,
+where applicable, an overall figure is also given.
+
+
It accepts the following option:
+
+- length
+Short window length in seconds, used for peak and trough RMS measurement.
+Default is 0.05 (50 milliseconds). Allowed range is [0 - 10].
+
+- metadata
+-
+
Set metadata injection. All the metadata keys are prefixed with lavfi.astats.X,
+where X is channel number starting from 1 or string Overall. Default is
+disabled.
+
+Available keys for each channel are:
+Bit_depth
+Crest_factor
+DC_offset
+Dynamic_range
+Entropy
+Flat_factor
+Max_difference
+Max_level
+Mean_difference
+Min_difference
+Min_level
+Noise_floor
+Noise_floor_count
+Number_of_Infs
+Number_of_NaNs
+Number_of_denormals
+Peak_count
+Peak_level
+RMS_difference
+RMS_peak
+RMS_trough
+Zero_crossings
+Zero_crossings_rate
+
+and for Overall:
+Bit_depth
+DC_offset
+Entropy
+Flat_factor
+Max_difference
+Max_level
+Mean_difference
+Min_difference
+Min_level
+Noise_floor
+Noise_floor_count
+Number_of_Infs
+Number_of_NaNs
+Number_of_denormals
+Number_of_samples
+Peak_count
+Peak_level
+RMS_difference
+RMS_level
+RMS_peak
+RMS_trough
+
+For example, a full key looks like lavfi.astats.1.DC_offset or
+lavfi.astats.Overall.Peak_count.
+
+Read below for the description of the keys.
+
+
+- reset
+Set the number of frames over which cumulative stats are calculated before
+being reset. Default is disabled.
+
+- measure_perchannel
+Select the parameters which are measured per channel. The metadata keys can
+be used as flags, default is all which measures everything.
+none disables all per channel measurement.
+
+- measure_overall
+Select the parameters which are measured overall. The metadata keys can
+be used as flags, default is all which measures everything.
+none disables all overall measurement.
+
+
+
+
A description of the measure keys follow:
+
+
+- none
+no measures
+
+- all
+all measures
+
+- Bit_depth
+overall bit depth of audio, i.e. number of bits used for each sample
+
+- Crest_factor
+standard ratio of peak to RMS level (note: not in dB)
+
+- DC_offset
+mean amplitude displacement from zero
+
+- Dynamic_range
+measured dynamic range of audio in dB
+
+- Entropy
+entropy measured across whole audio, entropy of value near 1.0 is typically measured for white noise
+
+- Flat_factor
+flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
+(i.e. either Min_level or Max_level)
+
+- Max_difference
+maximal difference between two consecutive samples
+
+- Max_level
+maximal sample level
+
+- Mean_difference
+mean difference between two consecutive samples, i.e. the average of each difference between two consecutive samples
+
+- Min_difference
+minimal difference between two consecutive samples
+
+- Min_level
+minimal sample level
+
+- Noise_floor
+minimum local peak measured in dBFS over a short window
+
+- Noise_floor_count
+number of occasions (not the number of samples) that the signal attained
+Noise floor
+
+- Number_of_Infs
+number of samples with an infinite value
+
+- Number_of_NaNs
+number of samples with a NaN (not a number) value
+
+- Number_of_denormals
+number of samples with a subnormal value
+
+- Number_of_samples
+number of samples
+
+- Peak_count
+number of occasions (not the number of samples) that the signal attained either
+Min_level or Max_level
+
+- Peak_level
+standard peak level measured in dBFS
+
+- RMS_difference
+Root Mean Square difference between two consecutive samples
+
+- RMS_level
+standard RMS level measured in dBFS
+
+- RMS_peak
+- RMS_trough
+peak and trough values for RMS level measured over a short window,
+measured in dBFS.
+
+- Zero crossings
+number of points where the waveform crosses the zero level axis
+
+- Zero crossings rate
+rate of Zero crossings and number of audio samples
+
+
+
+
+
36.57 asubboost
+
Boost subwoofer frequencies.
+
+
The filter accepts the following options:
+
+
+- dry
+Set dry gain, how much of original signal is kept. Allowed range is from 0 to 1.
+Default value is 1.0.
+
+- wet
+Set wet gain, how much of filtered signal is kept. Allowed range is from 0 to 1.
+Default value is 1.0.
+
+- boost
+Set max boost factor. Allowed range is from 1 to 12. Default value is 2.
+
+- decay
+Set delay line decay gain value. Allowed range is from 0 to 1.
+Default value is 0.0.
+
+- feedback
+Set delay line feedback gain value. Allowed range is from 0 to 1.
+Default value is 0.9.
+
+- cutoff
+Set cutoff frequency in Hertz. Allowed range is 50 to 900.
+Default value is 100.
+
+- slope
+Set slope amount for cutoff frequency. Allowed range is 0.0001 to 1.
+Default value is 0.5.
+
+- delay
+Set delay. Allowed range is from 1 to 100.
+Default value is 20.
+
+- channels
+Set the channels to process. Default value is all available.
+
+
+
+
+
36.57.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.58 asubcut
+
Cut subwoofer frequencies.
+
+
This filter allows to set custom, steeper
+roll off than highpass filter, and thus is able to more attenuate
+frequency content in stop-band.
+
+
The filter accepts the following options:
+
+
+- cutoff
+Set cutoff frequency in Hertz. Allowed range is 2 to 200.
+Default value is 20.
+
+- order
+Set filter order. Available values are from 3 to 20.
+Default value is 10.
+
+- level
+Set input gain level. Allowed range is from 0 to 1. Default value is 1.
+
+
+
+
+
36.58.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.59 asupercut
+
Cut super frequencies.
+
+
The filter accepts the following options:
+
+
+- cutoff
+Set cutoff frequency in Hertz. Allowed range is 20000 to 192000.
+Default value is 20000.
+
+- order
+Set filter order. Available values are from 3 to 20.
+Default value is 10.
+
+- level
+Set input gain level. Allowed range is from 0 to 1. Default value is 1.
+
+
+
+
+
36.59.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.60 asuperpass
+
Apply high order Butterworth band-pass filter.
+
+
The filter accepts the following options:
+
+
+- centerf
+Set center frequency in Hertz. Allowed range is 2 to 999999.
+Default value is 1000.
+
+- order
+Set filter order. Available values are from 4 to 20.
+Default value is 4.
+
+- qfactor
+Set Q-factor. Allowed range is from 0.01 to 100. Default value is 1.
+
+- level
+Set input gain level. Allowed range is from 0 to 2. Default value is 1.
+
+
+
+
+
36.60.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.61 asuperstop
+
Apply high order Butterworth band-stop filter.
+
+
The filter accepts the following options:
+
+
+- centerf
+Set center frequency in Hertz. Allowed range is 2 to 999999.
+Default value is 1000.
+
+- order
+Set filter order. Available values are from 4 to 20.
+Default value is 4.
+
+- qfactor
+Set Q-factor. Allowed range is from 0.01 to 100. Default value is 1.
+
+- level
+Set input gain level. Allowed range is from 0 to 2. Default value is 1.
+
+
+
+
+
36.61.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.62 atempo
+
+
Adjust audio tempo.
+
+
The filter accepts exactly one parameter, the audio tempo. If not
+specified then the filter will assume nominal 1.0 tempo. Tempo must
+be in the [0.5, 100.0] range.
+
+
Note that tempo greater than 2 will skip some samples rather than
+blend them in. If for any reason this is a concern it is always
+possible to daisy-chain several instances of atempo to achieve the
+desired product tempo.
+
+
+
+
36.62.1 Examples
+
+
+- Slow down audio to 80% tempo:
+
+
+
- To speed up audio to 300% tempo:
+
+
+
- To speed up audio to 300% tempo by daisy-chaining two atempo instances:
+
+
atempo=sqrt(3),atempo=sqrt(3)
+
+
+
+
+
36.62.2 Commands
+
+
This filter supports the following commands:
+
+- tempo
+Change filter tempo scale factor.
+Syntax for the command is : "tempo"
+
+
+
+
+
+
36.63 atilt
+
Apply spectral tilt filter to audio stream.
+
+
This filter apply any spectral roll-off slope over any specified frequency band.
+
+
The filter accepts the following options:
+
+
+- freq
+Set central frequency of tilt in Hz. Default is 10000 Hz.
+
+- slope
+Set slope direction of tilt. Default is 0. Allowed range is from -1 to 1.
+
+- width
+Set width of tilt. Default is 1000. Allowed range is from 100 to 10000.
+
+- order
+Set order of tilt filter.
+
+- level
+Set input volume level. Allowed range is from 0 to 4.
+Defalt is 1.
+
+
+
+
+
36.63.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.64 atrim
+
+
Trim the input so that the output contains one continuous subpart of the input.
+
+
It accepts the following parameters:
+
+- start
+Timestamp (in seconds) of the start of the section to keep. I.e. the audio
+sample with the timestamp start will be the first sample in the output.
+
+- end
+Specify time of the first audio sample that will be dropped, i.e. the
+audio sample immediately preceding the one with the timestamp end will be
+the last sample in the output.
+
+- start_pts
+Same as start, except this option sets the start timestamp in samples
+instead of seconds.
+
+- end_pts
+Same as end, except this option sets the end timestamp in samples instead
+of seconds.
+
+- duration
+The maximum duration of the output in seconds.
+
+- start_sample
+The number of the first sample that should be output.
+
+- end_sample
+The number of the first sample that should be dropped.
+
+
+
start, end, and duration are expressed as time
+duration specifications; see
+(ffmpeg-utils)the Time duration section in the ffmpeg-utils(1) manual.
+
+
Note that the first two sets of the start/end options and the duration
+option look at the frame timestamp, while the _sample options simply count the
+samples that pass through the filter. So start/end_pts and start/end_sample will
+give different results when the timestamps are wrong, inexact or do not start at
+zero. Also note that this filter does not modify the timestamps. If you wish
+to have the output timestamps start at zero, insert the asetpts filter after the
+atrim filter.
+
+
If multiple start or end options are set, this filter tries to be greedy and
+keep all samples that match at least one of the specified constraints. To keep
+only the part that matches all the constraints at once, chain multiple atrim
+filters.
+
+
The defaults are such that all the input is kept. So it is possible to set e.g.
+just the end values to keep everything before the specified time.
+
+
Examples:
+
+- Drop everything except the second minute of input:
+
+
ffmpeg -i INPUT -af atrim=60:120
+
- Keep only the first 1000 samples:
+
+
ffmpeg -i INPUT -af atrim=end_sample=1000
+
+
+
+
+
36.65 axcorrelate
+
Calculate normalized windowed cross-correlation between two input audio streams.
+
+
Resulted samples are always between -1 and 1 inclusive.
+If result is 1 it means two input samples are highly correlated in that selected segment.
+Result 0 means they are not correlated at all.
+If result is -1 it means two input samples are out of phase, which means they cancel each
+other.
+
+
The filter accepts the following options:
+
+
+- size
+Set size of segment over which cross-correlation is calculated.
+Default is 256. Allowed range is from 2 to 131072.
+
+- algo
+Set algorithm for cross-correlation. Can be slow or fast.
+Default is slow. Fast algorithm assumes mean values over any given segment
+are always zero and thus need much less calculations to make.
+This is generally not true, but is valid for typical audio streams.
+
+
+
+
+
36.65.1 Examples
+
+
+- Calculate correlation between channels in stereo audio stream:
+
+
ffmpeg -i stereo.wav -af channelsplit,axcorrelate=size=1024:algo=fast correlation.wav
+
+
+
+
+
+
36.66 bandpass
+
+
Apply a two-pole Butterworth band-pass filter with central
+frequency frequency, and (3dB-point) band-width width.
+The csg option selects a constant skirt gain (peak gain = Q)
+instead of the default: constant 0dB peak gain.
+The filter roll off at 6dB per octave (20dB per decade).
+
+
The filter accepts the following options:
+
+
+- frequency, f
+Set the filter’s central frequency. Default is 3000.
+
+- csg
+Constant skirt gain if set to 1. Defaults to 0.
+
+- width_type, t
+Set method to specify band-width of filter.
+
+- h
+Hz
+
- q
+Q-Factor
+
- o
+octave
+
- s
+slope
+
- k
+kHz
+
+
+- width, w
+Specify the band-width of a filter in width_type units.
+
+- mix, m
+How much to use filtered signal in output. Default is 1.
+Range is between 0 and 1.
+
+- channels, c
+Specify which channels to filter, by default all available are filtered.
+
+- normalize, n
+Normalize biquad coefficients, by default is disabled.
+Enabling it will normalize magnitude response at DC to 0dB.
+
+- transform, a
+Set transform type of IIR filter.
+
+- di
+- dii
+- tdi
+- tdii
+- latt
+- svf
+- zdf
+
+
+- precision, r
+Set precison of filtering.
+
+- auto
+Pick automatic sample format depending on surround filters.
+
- s16
+Always use signed 16-bit.
+
- s32
+Always use signed 32-bit.
+
- f32
+Always use float 32-bit.
+
- f64
+Always use float 64-bit.
+
+
+- block_size, b
+Set block size used for reverse IIR processing. If this value is set to high enough
+value (higher than impulse response length truncated when reaches near zero values) filtering
+will become linear phase otherwise if not big enough it will just produce nasty artifacts.
+
+Note that filter delay will be exactly this many samples when set to non-zero value.
+
+
+
+
+
36.66.1 Commands
+
+
This filter supports the following commands:
+
+- frequency, f
+Change bandpass frequency.
+Syntax for the command is : "frequency"
+
+- width_type, t
+Change bandpass width_type.
+Syntax for the command is : "width_type"
+
+- width, w
+Change bandpass width.
+Syntax for the command is : "width"
+
+- mix, m
+Change bandpass mix.
+Syntax for the command is : "mix"
+
+
+
+
+
+
36.67 bandreject
+
+
Apply a two-pole Butterworth band-reject filter with central
+frequency frequency, and (3dB-point) band-width width.
+The filter roll off at 6dB per octave (20dB per decade).
+
+
The filter accepts the following options:
+
+
+- frequency, f
+Set the filter’s central frequency. Default is 3000.
+
+- width_type, t
+Set method to specify band-width of filter.
+
+- h
+Hz
+
- q
+Q-Factor
+
- o
+octave
+
- s
+slope
+
- k
+kHz
+
+
+- width, w
+Specify the band-width of a filter in width_type units.
+
+- mix, m
+How much to use filtered signal in output. Default is 1.
+Range is between 0 and 1.
+
+- channels, c
+Specify which channels to filter, by default all available are filtered.
+
+- normalize, n
+Normalize biquad coefficients, by default is disabled.
+Enabling it will normalize magnitude response at DC to 0dB.
+
+- transform, a
+Set transform type of IIR filter.
+
+- di
+- dii
+- tdi
+- tdii
+- latt
+- svf
+- zdf
+
+
+- precision, r
+Set precison of filtering.
+
+- auto
+Pick automatic sample format depending on surround filters.
+
- s16
+Always use signed 16-bit.
+
- s32
+Always use signed 32-bit.
+
- f32
+Always use float 32-bit.
+
- f64
+Always use float 64-bit.
+
+
+- block_size, b
+Set block size used for reverse IIR processing. If this value is set to high enough
+value (higher than impulse response length truncated when reaches near zero values) filtering
+will become linear phase otherwise if not big enough it will just produce nasty artifacts.
+
+Note that filter delay will be exactly this many samples when set to non-zero value.
+
+
+
+
+
36.67.1 Commands
+
+
This filter supports the following commands:
+
+- frequency, f
+Change bandreject frequency.
+Syntax for the command is : "frequency"
+
+- width_type, t
+Change bandreject width_type.
+Syntax for the command is : "width_type"
+
+- width, w
+Change bandreject width.
+Syntax for the command is : "width"
+
+- mix, m
+Change bandreject mix.
+Syntax for the command is : "mix"
+
+
+
+
+
+
36.68 bass, lowshelf
+
+
Boost or cut the bass (lower) frequencies of the audio using a two-pole
+shelving filter with a response similar to that of a standard
+hi-fi’s tone-controls. This is also known as shelving equalisation (EQ).
+
+
The filter accepts the following options:
+
+
+- gain, g
+Give the gain at 0 Hz. Its useful range is about -20
+(for a large cut) to +20 (for a large boost).
+Beware of clipping when using a positive gain.
+
+- frequency, f
+Set the filter’s central frequency and so can be used
+to extend or reduce the frequency range to be boosted or cut.
+The default value is 100 Hz.
+
+- width_type, t
+Set method to specify band-width of filter.
+
+- h
+Hz
+
- q
+Q-Factor
+
- o
+octave
+
- s
+slope
+
- k
+kHz
+
+
+- width, w
+Determine how steep is the filter’s shelf transition.
+
+- poles, p
+Set number of poles. Default is 2.
+
+- mix, m
+How much to use filtered signal in output. Default is 1.
+Range is between 0 and 1.
+
+- channels, c
+Specify which channels to filter, by default all available are filtered.
+
+- normalize, n
+Normalize biquad coefficients, by default is disabled.
+Enabling it will normalize magnitude response at DC to 0dB.
+
+- transform, a
+Set transform type of IIR filter.
+
+- di
+- dii
+- tdi
+- tdii
+- latt
+- svf
+- zdf
+
+
+- precision, r
+Set precison of filtering.
+
+- auto
+Pick automatic sample format depending on surround filters.
+
- s16
+Always use signed 16-bit.
+
- s32
+Always use signed 32-bit.
+
- f32
+Always use float 32-bit.
+
- f64
+Always use float 64-bit.
+
+
+- block_size, b
+Set block size used for reverse IIR processing. If this value is set to high enough
+value (higher than impulse response length truncated when reaches near zero values) filtering
+will become linear phase otherwise if not big enough it will just produce nasty artifacts.
+
+Note that filter delay will be exactly this many samples when set to non-zero value.
+
+
+
+
+
36.68.1 Commands
+
+
This filter supports the following commands:
+
+- frequency, f
+Change bass frequency.
+Syntax for the command is : "frequency"
+
+- width_type, t
+Change bass width_type.
+Syntax for the command is : "width_type"
+
+- width, w
+Change bass width.
+Syntax for the command is : "width"
+
+- gain, g
+Change bass gain.
+Syntax for the command is : "gain"
+
+- mix, m
+Change bass mix.
+Syntax for the command is : "mix"
+
+
+
+
+
+
36.69 biquad
+
+
Apply a biquad IIR filter with the given coefficients.
+Where b0, b1, b2 and a0, a1, a2
+are the numerator and denominator coefficients respectively.
+and channels, c specify which channels to filter, by default all
+available are filtered.
+
+
+
+
36.69.1 Commands
+
+
This filter supports the following commands:
+
+- a0
+- a1
+- a2
+- b0
+- b1
+- b2
+Change biquad parameter.
+Syntax for the command is : "value"
+
+- mix, m
+How much to use filtered signal in output. Default is 1.
+Range is between 0 and 1.
+
+- channels, c
+Specify which channels to filter, by default all available are filtered.
+
+- normalize, n
+Normalize biquad coefficients, by default is disabled.
+Enabling it will normalize magnitude response at DC to 0dB.
+
+- transform, a
+Set transform type of IIR filter.
+
+- di
+- dii
+- tdi
+- tdii
+- latt
+- svf
+- zdf
+
+
+- precision, r
+Set precison of filtering.
+
+- auto
+Pick automatic sample format depending on surround filters.
+
- s16
+Always use signed 16-bit.
+
- s32
+Always use signed 32-bit.
+
- f32
+Always use float 32-bit.
+
- f64
+Always use float 64-bit.
+
+
+- block_size, b
+Set block size used for reverse IIR processing. If this value is set to high enough
+value (higher than impulse response length truncated when reaches near zero values) filtering
+will become linear phase otherwise if not big enough it will just produce nasty artifacts.
+
+Note that filter delay will be exactly this many samples when set to non-zero value.
+
+
+
+
+
+
36.70 bs2b
+
Bauer stereo to binaural transformation, which improves headphone listening of
+stereo audio records.
+
+
To enable compilation of this filter you need to configure FFmpeg with
+--enable-libbs2b.
+
+
It accepts the following parameters:
+
+- profile
+Pre-defined crossfeed level.
+
+- default
+Default level (fcut=700, feed=50).
+
+- cmoy
+Chu Moy circuit (fcut=700, feed=60).
+
+- jmeier
+Jan Meier circuit (fcut=650, feed=95).
+
+
+
+- fcut
+Cut frequency (in Hz).
+
+- feed
+Feed level (in Hz).
+
+
+
+
+
+
36.71 channelmap
+
+
Remap input channels to new locations.
+
+
It accepts the following parameters:
+
+- map
+Map channels from input to output. The argument is a ’|’-separated list of
+mappings, each in the in_channel-out_channel or
+in_channel form. in_channel can be either the name of the input
+channel (e.g. FL for front left) or its index in the input channel layout.
+out_channel is the name of the output channel or its index in the output
+channel layout. If out_channel is not given then it is implicitly an
+index, starting with zero and increasing by one for each mapping.
+
+- channel_layout
+The channel layout of the output stream.
+
+
+
If no mapping is present, the filter will implicitly map input channels to
+output channels, preserving indices.
+
+
+
+
36.71.1 Examples
+
+
+
+
+
+
+
36.72 channelsplit
+
+
Split each channel from an input audio stream into a separate output stream.
+
+
It accepts the following parameters:
+
+- channel_layout
+The channel layout of the input stream. The default is "stereo".
+
- channels
+A channel layout describing the channels to be extracted as separate output streams
+or "all" to extract each input channel as a separate stream. The default is "all".
+
+Choosing channels not present in channel layout in the input will result in an error.
+
+
+
+
+
36.72.1 Examples
+
+
+
+
+
+
+
36.73 chorus
+
Add a chorus effect to the audio.
+
+
Can make a single vocal sound like a chorus, but can also be applied to instrumentation.
+
+
Chorus resembles an echo effect with a short delay, but whereas with echo the delay is
+constant, with chorus, it is varied using using sinusoidal or triangular modulation.
+The modulation depth defines the range the modulated delay is played before or after
+the delay. Hence the delayed sound will sound slower or faster, that is the delayed
+sound tuned around the original one, like in a chorus where some vocals are slightly
+off key.
+
+
It accepts the following parameters:
+
+- in_gain
+Set input gain. Default is 0.4.
+
+- out_gain
+Set output gain. Default is 0.4.
+
+- delays
+Set delays. A typical delay is around 40ms to 60ms.
+
+- decays
+Set decays.
+
+- speeds
+Set speeds.
+
+- depths
+Set depths.
+
+
+
+
+
36.73.1 Examples
+
+
+- A single delay:
+
+
chorus=0.7:0.9:55:0.4:0.25:2
+
- Two delays:
+
+
chorus=0.6:0.9:50|60:0.4|0.32:0.25|0.4:2|1.3
+
- Fuller sounding chorus with three delays:
+
+
chorus=0.5:0.9:50|60|40:0.4|0.32|0.3:0.25|0.4|0.3:2|2.3|1.3
+
+
+
+
+
+
36.74 compand
+
Compress or expand the audio’s dynamic range.
+
+
It accepts the following parameters:
+
+
+- attacks
+- decays
+A list of times in seconds for each channel over which the instantaneous level
+of the input signal is averaged to determine its volume. attacks refers to
+increase of volume and decays refers to decrease of volume. For most
+situations, the attack time (response to the audio getting louder) should be
+shorter than the decay time, because the human ear is more sensitive to sudden
+loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
+a typical value for decay is 0.8 seconds.
+If specified number of attacks & decays is lower than number of channels, the last
+set attack/decay will be used for all remaining channels.
+
+- points
+A list of points for the transfer function, specified in dB relative to the
+maximum possible signal amplitude. Each key points list must be defined using
+the following syntax: x0/y0|x1/y1|x2/y2|.... or
+x0/y0 x1/y1 x2/y2 ....
+
+The input values must be in strictly increasing order but the transfer function
+does not have to be monotonically rising. The point 0/0 is assumed but
+may be overridden (by 0/out-dBn). Typical values for the transfer
+function are -70/-70|-60/-20|1/0.
+
+- soft-knee
+Set the curve radius in dB for all joints. It defaults to 0.01.
+
+- gain
+Set the additional gain in dB to be applied at all points on the transfer
+function. This allows for easy adjustment of the overall gain.
+It defaults to 0.
+
+- volume
+Set an initial volume, in dB, to be assumed for each channel when filtering
+starts. This permits the user to supply a nominal level initially, so that, for
+example, a very large gain is not applied to initial signal levels before the
+companding has begun to operate. A typical value for audio which is initially
+quiet is -90 dB. It defaults to 0.
+
+- delay
+Set a delay, in seconds. The input audio is analyzed immediately, but audio is
+delayed before being fed to the volume adjuster. Specifying a delay
+approximately equal to the attack/decay times allows the filter to effectively
+operate in predictive rather than reactive mode. It defaults to 0.
+
+
+
+
+
+
36.74.1 Examples
+
+
+
+
+
+
+
36.75 compensationdelay
+
+
Compensation Delay Line is a metric based delay to compensate differing
+positions of microphones or speakers.
+
+
For example, you have recorded guitar with two microphones placed in
+different locations. Because the front of sound wave has fixed speed in
+normal conditions, the phasing of microphones can vary and depends on
+their location and interposition. The best sound mix can be achieved when
+these microphones are in phase (synchronized). Note that a distance of
+~30 cm between microphones makes one microphone capture the signal in
+antiphase to the other microphone. That makes the final mix sound moody.
+This filter helps to solve phasing problems by adding different delays
+to each microphone track and make them synchronized.
+
+
The best result can be reached when you take one track as base and
+synchronize other tracks one by one with it.
+Remember that synchronization/delay tolerance depends on sample rate, too.
+Higher sample rates will give more tolerance.
+
+
The filter accepts the following parameters:
+
+
+- mm
+Set millimeters distance. This is compensation distance for fine tuning.
+Default is 0.
+
+- cm
+Set cm distance. This is compensation distance for tightening distance setup.
+Default is 0.
+
+- m
+Set meters distance. This is compensation distance for hard distance setup.
+Default is 0.
+
+- dry
+Set dry amount. Amount of unprocessed (dry) signal.
+Default is 0.
+
+- wet
+Set wet amount. Amount of processed (wet) signal.
+Default is 1.
+
+- temp
+Set temperature in degrees Celsius. This is the temperature of the environment.
+Default is 20.
+
+
+
+
+
36.75.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.76 crossfeed
+
Apply headphone crossfeed filter.
+
+
Crossfeed is the process of blending the left and right channels of stereo
+audio recording.
+It is mainly used to reduce extreme stereo separation of low frequencies.
+
+
The intent is to produce more speaker like sound to the listener.
+
+
The filter accepts the following options:
+
+
+- strength
+Set strength of crossfeed. Default is 0.2. Allowed range is from 0 to 1.
+This sets gain of low shelf filter for side part of stereo image.
+Default is -6dB. Max allowed is -30db when strength is set to 1.
+
+- range
+Set soundstage wideness. Default is 0.5. Allowed range is from 0 to 1.
+This sets cut off frequency of low shelf filter. Default is cut off near
+1550 Hz. With range set to 1 cut off frequency is set to 2100 Hz.
+
+- slope
+Set curve slope of low shelf filter. Default is 0.5.
+Allowed range is from 0.01 to 1.
+
+- level_in
+Set input gain. Default is 0.9.
+
+- level_out
+Set output gain. Default is 1.
+
+- block_size
+Set block size used for reverse IIR processing. If this value is set to high enough
+value (higher than impulse response length truncated when reaches near zero values) filtering
+will become linear phase otherwise if not big enough it will just produce nasty artifacts.
+
+Note that filter delay will be exactly this many samples when set to non-zero value.
+
+
+
+
+
36.76.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.77 crystalizer
+
Simple algorithm for audio noise sharpening.
+
+
This filter linearly increases differences betweeen each audio sample.
+
+
The filter accepts the following options:
+
+
+- i
+Sets the intensity of effect (default: 2.0). Must be in range between -10.0 to 0
+(unchanged sound) to 10.0 (maximum effect).
+To inverse filtering use negative value.
+
+- c
+Enable clipping. By default is enabled.
+
+
+
+
+
36.77.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.78 dcshift
+
Apply a DC shift to the audio.
+
+
This can be useful to remove a DC offset (caused perhaps by a hardware problem
+in the recording chain) from the audio. The effect of a DC offset is reduced
+headroom and hence volume. The astats filter can be used to determine if
+a signal has a DC offset.
+
+
+- shift
+Set the DC shift, allowed range is [-1, 1]. It indicates the amount to shift
+the audio.
+
+- limitergain
+Optional. It should have a value much less than 1 (e.g. 0.05 or 0.02) and is
+used to prevent clipping.
+
+
+
+
+
36.79 deesser
+
+
Apply de-essing to the audio samples.
+
+
+- i
+Set intensity for triggering de-essing. Allowed range is from 0 to 1.
+Default is 0.
+
+- m
+Set amount of ducking on treble part of sound. Allowed range is from 0 to 1.
+Default is 0.5.
+
+- f
+How much of original frequency content to keep when de-essing. Allowed range is from 0 to 1.
+Default is 0.5.
+
+- s
+Set the output mode.
+
+It accepts the following values:
+
+- i
+Pass input unchanged.
+
+- o
+Pass ess filtered out.
+
+- e
+Pass only ess.
+
+Default value is o.
+
+
+
+
+
+
+
36.80 dialoguenhance
+
Enhance dialogue in stereo audio.
+
+
This filter accepts stereo input and produce surround (3.0) channels output.
+The newly produced front center channel have enhanced speech dialogue originally
+available in both stereo channels.
+This filter outputs front left and front right channels same as available in stereo input.
+
+
The filter accepts the following options:
+
+
+- original
+Set the original center factor to keep in front center channel output.
+Allowed range is from 0 to 1. Default value is 1.
+
+- enhance
+Set the dialogue enhance factor to put in front center channel output.
+Allowed range is from 0 to 3. Default value is 1.
+
+- voice
+Set the voice detection factor.
+Allowed range is from 2 to 32. Default value is 2.
+
+
+
+
+
36.80.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.81 drmeter
+
Measure audio dynamic range.
+
+
DR values of 14 and higher is found in very dynamic material. DR of 8 to 13
+is found in transition material. And anything less that 8 have very poor dynamics
+and is very compressed.
+
+
The filter accepts the following options:
+
+
+- length
+Set window length in seconds used to split audio into segments of equal length.
+Default is 3 seconds.
+
+
+
+
+
36.82 dynaudnorm
+
Dynamic Audio Normalizer.
+
+
This filter applies a certain amount of gain to the input audio in order
+to bring its peak magnitude to a target level (e.g. 0 dBFS). However, in
+contrast to more "simple" normalization algorithms, the Dynamic Audio
+Normalizer *dynamically* re-adjusts the gain factor to the input audio.
+This allows for applying extra gain to the "quiet" sections of the audio
+while avoiding distortions or clipping the "loud" sections. In other words:
+The Dynamic Audio Normalizer will "even out" the volume of quiet and loud
+sections, in the sense that the volume of each section is brought to the
+same target level. Note, however, that the Dynamic Audio Normalizer achieves
+this goal *without* applying "dynamic range compressing". It will retain 100%
+of the dynamic range *within* each section of the audio file.
+
+
+- framelen, f
+Set the frame length in milliseconds. In range from 10 to 8000 milliseconds.
+Default is 500 milliseconds.
+The Dynamic Audio Normalizer processes the input audio in small chunks,
+referred to as frames. This is required, because a peak magnitude has no
+meaning for just a single sample value. Instead, we need to determine the
+peak magnitude for a contiguous sequence of sample values. While a "standard"
+normalizer would simply use the peak magnitude of the complete file, the
+Dynamic Audio Normalizer determines the peak magnitude individually for each
+frame. The length of a frame is specified in milliseconds. By default, the
+Dynamic Audio Normalizer uses a frame length of 500 milliseconds, which has
+been found to give good results with most files.
+Note that the exact frame length, in number of samples, will be determined
+automatically, based on the sampling rate of the individual input audio file.
+
+- gausssize, g
+Set the Gaussian filter window size. In range from 3 to 301, must be odd
+number. Default is 31.
+Probably the most important parameter of the Dynamic Audio Normalizer is the
+window size of the Gaussian smoothing filter. The filter’s window size
+is specified in frames, centered around the current frame. For the sake of
+simplicity, this must be an odd number. Consequently, the default value of 31
+takes into account the current frame, as well as the 15 preceding frames and
+the 15 subsequent frames. Using a larger window results in a stronger
+smoothing effect and thus in less gain variation, i.e. slower gain
+adaptation. Conversely, using a smaller window results in a weaker smoothing
+effect and thus in more gain variation, i.e. faster gain adaptation.
+In other words, the more you increase this value, the more the Dynamic Audio
+Normalizer will behave like a "traditional" normalization filter. On the
+contrary, the more you decrease this value, the more the Dynamic Audio
+Normalizer will behave like a dynamic range compressor.
+
+- peak, p
+Set the target peak value. This specifies the highest permissible magnitude
+level for the normalized audio input. This filter will try to approach the
+target peak magnitude as closely as possible, but at the same time it also
+makes sure that the normalized signal will never exceed the peak magnitude.
+A frame’s maximum local gain factor is imposed directly by the target peak
+magnitude. The default value is 0.95 and thus leaves a headroom of 5%*.
+It is not recommended to go above this value.
+
+- maxgain, m
+Set the maximum gain factor. In range from 1.0 to 100.0. Default is 10.0.
+The Dynamic Audio Normalizer determines the maximum possible (local) gain
+factor for each input frame, i.e. the maximum gain factor that does not
+result in clipping or distortion. The maximum gain factor is determined by
+the frame’s highest magnitude sample. However, the Dynamic Audio Normalizer
+additionally bounds the frame’s maximum gain factor by a predetermined
+(global) maximum gain factor. This is done in order to avoid excessive gain
+factors in "silent" or almost silent frames. By default, the maximum gain
+factor is 10.0, For most inputs the default value should be sufficient and
+it usually is not recommended to increase this value. Though, for input
+with an extremely low overall volume level, it may be necessary to allow even
+higher gain factors. Note, however, that the Dynamic Audio Normalizer does
+not simply apply a "hard" threshold (i.e. cut off values above the threshold).
+Instead, a "sigmoid" threshold function will be applied. This way, the
+gain factors will smoothly approach the threshold value, but never exceed that
+value.
+
+- targetrms, r
+Set the target RMS. In range from 0.0 to 1.0. Default is 0.0 - disabled.
+By default, the Dynamic Audio Normalizer performs "peak" normalization.
+This means that the maximum local gain factor for each frame is defined
+(only) by the frame’s highest magnitude sample. This way, the samples can
+be amplified as much as possible without exceeding the maximum signal
+level, i.e. without clipping. Optionally, however, the Dynamic Audio
+Normalizer can also take into account the frame’s root mean square,
+abbreviated RMS. In electrical engineering, the RMS is commonly used to
+determine the power of a time-varying signal. It is therefore considered
+that the RMS is a better approximation of the "perceived loudness" than
+just looking at the signal’s peak magnitude. Consequently, by adjusting all
+frames to a constant RMS value, a uniform "perceived loudness" can be
+established. If a target RMS value has been specified, a frame’s local gain
+factor is defined as the factor that would result in exactly that RMS value.
+Note, however, that the maximum local gain factor is still restricted by the
+frame’s highest magnitude sample, in order to prevent clipping.
+
+- coupling, n
+Enable channels coupling. By default is enabled.
+By default, the Dynamic Audio Normalizer will amplify all channels by the same
+amount. This means the same gain factor will be applied to all channels, i.e.
+the maximum possible gain factor is determined by the "loudest" channel.
+However, in some recordings, it may happen that the volume of the different
+channels is uneven, e.g. one channel may be "quieter" than the other one(s).
+In this case, this option can be used to disable the channel coupling. This way,
+the gain factor will be determined independently for each channel, depending
+only on the individual channel’s highest magnitude sample. This allows for
+harmonizing the volume of the different channels.
+
+- correctdc, c
+Enable DC bias correction. By default is disabled.
+An audio signal (in the time domain) is a sequence of sample values.
+In the Dynamic Audio Normalizer these sample values are represented in the
+-1.0 to 1.0 range, regardless of the original input format. Normally, the
+audio signal, or "waveform", should be centered around the zero point.
+That means if we calculate the mean value of all samples in a file, or in a
+single frame, then the result should be 0.0 or at least very close to that
+value. If, however, there is a significant deviation of the mean value from
+0.0, in either positive or negative direction, this is referred to as a
+DC bias or DC offset. Since a DC bias is clearly undesirable, the Dynamic
+Audio Normalizer provides optional DC bias correction.
+With DC bias correction enabled, the Dynamic Audio Normalizer will determine
+the mean value, or "DC correction" offset, of each input frame and subtract
+that value from all of the frame’s sample values which ensures those samples
+are centered around 0.0 again. Also, in order to avoid "gaps" at the frame
+boundaries, the DC correction offset values will be interpolated smoothly
+between neighbouring frames.
+
+- altboundary, b
+Enable alternative boundary mode. By default is disabled.
+The Dynamic Audio Normalizer takes into account a certain neighbourhood
+around each frame. This includes the preceding frames as well as the
+subsequent frames. However, for the "boundary" frames, located at the very
+beginning and at the very end of the audio file, not all neighbouring
+frames are available. In particular, for the first few frames in the audio
+file, the preceding frames are not known. And, similarly, for the last few
+frames in the audio file, the subsequent frames are not known. Thus, the
+question arises which gain factors should be assumed for the missing frames
+in the "boundary" region. The Dynamic Audio Normalizer implements two modes
+to deal with this situation. The default boundary mode assumes a gain factor
+of exactly 1.0 for the missing frames, resulting in a smooth "fade in" and
+"fade out" at the beginning and at the end of the input, respectively.
+
+- compress, s
+Set the compress factor. In range from 0.0 to 30.0. Default is 0.0.
+By default, the Dynamic Audio Normalizer does not apply "traditional"
+compression. This means that signal peaks will not be pruned and thus the
+full dynamic range will be retained within each local neighbourhood. However,
+in some cases it may be desirable to combine the Dynamic Audio Normalizer’s
+normalization algorithm with a more "traditional" compression.
+For this purpose, the Dynamic Audio Normalizer provides an optional compression
+(thresholding) function. If (and only if) the compression feature is enabled,
+all input frames will be processed by a soft knee thresholding function prior
+to the actual normalization process. Put simply, the thresholding function is
+going to prune all samples whose magnitude exceeds a certain threshold value.
+However, the Dynamic Audio Normalizer does not simply apply a fixed threshold
+value. Instead, the threshold value will be adjusted for each individual
+frame.
+In general, smaller parameters result in stronger compression, and vice versa.
+Values below 3.0 are not recommended, because audible distortion may appear.
+
+- threshold, t
+Set the target threshold value. This specifies the lowest permissible
+magnitude level for the audio input which will be normalized.
+If input frame volume is above this value frame will be normalized.
+Otherwise frame may not be normalized at all. The default value is set
+to 0, which means all input frames will be normalized.
+This option is mostly useful if digital noise is not wanted to be amplified.
+
+- channels, h
+Specify which channels to filter, by default all available channels are filtered.
+
+- overlap, o
+Specify overlap for frames. If set to 0 (default) no frame overlapping is done.
+Using >0 and <1 values will make less conservative gain adjustments, like
+when framelen option is set to smaller value, if framelen option value is
+compensated for non-zero overlap then gain adjustments will be smoother across time
+compared to zero overlap case.
+
+- curve, v
+Specify the peak mapping curve expression which is going to be used when calculating
+gain applied to frames. The max output frame gain will still be limited by other
+options mentioned previously for this filter.
+
+The expression can contain the following constants:
+
+
+- ch
+current channel number
+
+- sn
+current sample number
+
+- nb_channels
+number of channels
+
+- t
+timestamp expressed in seconds
+
+- sr
+sample rate
+
+- p
+current frame peak value
+
+
+
+
+
+
36.82.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.83 earwax
+
+
Make audio easier to listen to on headphones.
+
+
This filter adds ‘cues’ to 44.1kHz stereo (i.e. audio CD format) audio
+so that when listened to on headphones the stereo image is moved from
+inside your head (standard for headphones) to outside and in front of
+the listener (standard for speakers).
+
+
Ported from SoX.
+
+
+
+
36.84 equalizer
+
+
Apply a two-pole peaking equalisation (EQ) filter. With this
+filter, the signal-level at and around a selected frequency can
+be increased or decreased, whilst (unlike bandpass and bandreject
+filters) that at all other frequencies is unchanged.
+
+
In order to produce complex equalisation curves, this filter can
+be given several times, each with a different central frequency.
+
+
The filter accepts the following options:
+
+
+- frequency, f
+Set the filter’s central frequency in Hz.
+
+- width_type, t
+Set method to specify band-width of filter.
+
+- h
+Hz
+
- q
+Q-Factor
+
- o
+octave
+
- s
+slope
+
- k
+kHz
+
+
+- width, w
+Specify the band-width of a filter in width_type units.
+
+- gain, g
+Set the required gain or attenuation in dB.
+Beware of clipping when using a positive gain.
+
+- mix, m
+How much to use filtered signal in output. Default is 1.
+Range is between 0 and 1.
+
+- channels, c
+Specify which channels to filter, by default all available are filtered.
+
+- normalize, n
+Normalize biquad coefficients, by default is disabled.
+Enabling it will normalize magnitude response at DC to 0dB.
+
+- transform, a
+Set transform type of IIR filter.
+
+- di
+- dii
+- tdi
+- tdii
+- latt
+- svf
+- zdf
+
+
+- precision, r
+Set precison of filtering.
+
+- auto
+Pick automatic sample format depending on surround filters.
+
- s16
+Always use signed 16-bit.
+
- s32
+Always use signed 32-bit.
+
- f32
+Always use float 32-bit.
+
- f64
+Always use float 64-bit.
+
+
+- block_size, b
+Set block size used for reverse IIR processing. If this value is set to high enough
+value (higher than impulse response length truncated when reaches near zero values) filtering
+will become linear phase otherwise if not big enough it will just produce nasty artifacts.
+
+Note that filter delay will be exactly this many samples when set to non-zero value.
+
+
+
+
+
36.84.1 Examples
+
+- Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
+
+
equalizer=f=1000:t=h:width=200:g=-10
+
- Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
+
+
equalizer=f=1000:t=q:w=1:g=2,equalizer=f=100:t=q:w=2:g=-5
+
+
+
+
+
36.84.2 Commands
+
+
This filter supports the following commands:
+
+- frequency, f
+Change equalizer frequency.
+Syntax for the command is : "frequency"
+
+- width_type, t
+Change equalizer width_type.
+Syntax for the command is : "width_type"
+
+- width, w
+Change equalizer width.
+Syntax for the command is : "width"
+
+- gain, g
+Change equalizer gain.
+Syntax for the command is : "gain"
+
+- mix, m
+Change equalizer mix.
+Syntax for the command is : "mix"
+
+
+
+
+
+
+
36.86 firequalizer
+
Apply FIR Equalization using arbitrary frequency response.
+
+
The filter accepts the following option:
+
+
+- gain
+Set gain curve equation (in dB). The expression can contain variables:
+
+- f
+the evaluated frequency
+
- sr
+sample rate
+
- ch
+channel number, set to 0 when multichannels evaluation is disabled
+
- chid
+channel id, see libavutil/channel_layout.h, set to the first channel id when
+multichannels evaluation is disabled
+
- chs
+number of channels
+
- chlayout
+channel_layout, see libavutil/channel_layout.h
+
+
+and functions:
+
+- gain_interpolate(f)
+interpolate gain on frequency f based on gain_entry
+
- cubic_interpolate(f)
+same as gain_interpolate, but smoother
+
+This option is also available as command. Default is gain_interpolate(f).
+
+- gain_entry
+Set gain entry for gain_interpolate function. The expression can
+contain functions:
+
+- entry(f, g)
+store gain entry at frequency f with value g
+
+This option is also available as command.
+
+- delay
+Set filter delay in seconds. Higher value means more accurate.
+Default is 0.01.
+
+- accuracy
+Set filter accuracy in Hz. Lower value means more accurate.
+Default is 5.
+
+- wfunc
+Set window function. Acceptable values are:
+
+- rectangular
+rectangular window, useful when gain curve is already smooth
+
- hann
+hann window (default)
+
- hamming
+hamming window
+
- blackman
+blackman window
+
- nuttall3
+3-terms continuous 1st derivative nuttall window
+
- mnuttall3
+minimum 3-terms discontinuous nuttall window
+
- nuttall
+4-terms continuous 1st derivative nuttall window
+
- bnuttall
+minimum 4-terms discontinuous nuttall (blackman-nuttall) window
+
- bharris
+blackman-harris window
+
- tukey
+tukey window
+
+
+- fixed
+If enabled, use fixed number of audio samples. This improves speed when
+filtering with large delay. Default is disabled.
+
+- multi
+Enable multichannels evaluation on gain. Default is disabled.
+
+- zero_phase
+Enable zero phase mode by subtracting timestamp to compensate delay.
+Default is disabled.
+
+- scale
+Set scale used by gain. Acceptable values are:
+
+- linlin
+linear frequency, linear gain
+
- linlog
+linear frequency, logarithmic (in dB) gain (default)
+
- loglin
+logarithmic (in octave scale where 20 Hz is 0) frequency, linear gain
+
- loglog
+logarithmic frequency, logarithmic gain
+
+
+- dumpfile
+Set file for dumping, suitable for gnuplot.
+
+- dumpscale
+Set scale for dumpfile. Acceptable values are same with scale option.
+Default is linlog.
+
+- fft2
+Enable 2-channel convolution using complex FFT. This improves speed significantly.
+Default is disabled.
+
+- min_phase
+Enable minimum phase impulse response. Default is disabled.
+
+
+
+
+
36.86.1 Examples
+
+- lowpass at 1000 Hz:
+
+
firequalizer=gain='if(lt(f,1000), 0, -INF)'
+
- lowpass at 1000 Hz with gain_entry:
+
+
firequalizer=gain_entry='entry(1000,0); entry(1001, -INF)'
+
- custom equalization:
+
+
firequalizer=gain_entry='entry(100,0); entry(400, -4); entry(1000, -6); entry(2000, 0)'
+
- higher delay with zero phase to compensate delay:
+
+
firequalizer=delay=0.1:fixed=on:zero_phase=on
+
- lowpass on left channel, highpass on right channel:
+
+
firequalizer=gain='if(eq(chid,1), gain_interpolate(f), if(eq(chid,2), gain_interpolate(1e6+f), 0))'
+:gain_entry='entry(1000, 0); entry(1001,-INF); entry(1e6+1000,0)':multi=on
+
+
+
+
+
+
36.87 flanger
+
Apply a flanging effect to the audio.
+
+
The filter accepts the following options:
+
+
+- delay
+Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
+
+- depth
+Set added sweep delay in milliseconds. Range from 0 to 10. Default value is 2.
+
+- regen
+Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
+Default value is 0.
+
+- width
+Set percentage of delayed signal mixed with original. Range from 0 to 100.
+Default value is 71.
+
+- speed
+Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
+
+- shape
+Set swept wave shape, can be triangular or sinusoidal.
+Default value is sinusoidal.
+
+- phase
+Set swept wave percentage-shift for multi channel. Range from 0 to 100.
+Default value is 25.
+
+- interp
+Set delay-line interpolation, linear or quadratic.
+Default is linear.
+
+
+
+
+
36.88 haas
+
Apply Haas effect to audio.
+
+
Note that this makes most sense to apply on mono signals.
+With this filter applied to mono signals it give some directionality and
+stretches its stereo image.
+
+
The filter accepts the following options:
+
+
+- level_in
+Set input level. By default is 1, or 0dB
+
+- level_out
+Set output level. By default is 1, or 0dB.
+
+- side_gain
+Set gain applied to side part of signal. By default is 1.
+
+- middle_source
+Set kind of middle source. Can be one of the following:
+
+
+- ‘left’
+Pick left channel.
+
+- ‘right’
+Pick right channel.
+
+- ‘mid’
+Pick middle part signal of stereo image.
+
+- ‘side’
+Pick side part signal of stereo image.
+
+
+- middle_phase
+Change middle phase. By default is disabled.
+
+- left_delay
+Set left channel delay. By default is 2.05 milliseconds.
+
+- left_balance
+Set left channel balance. By default is -1.
+
+- left_gain
+Set left channel gain. By default is 1.
+
+- left_phase
+Change left phase. By default is disabled.
+
+- right_delay
+Set right channel delay. By defaults is 2.12 milliseconds.
+
+- right_balance
+Set right channel balance. By default is 1.
+
+- right_gain
+Set right channel gain. By default is 1.
+
+- right_phase
+Change right phase. By default is enabled.
+
+
+
+
+
36.89 hdcd
+
+
Decodes High Definition Compatible Digital (HDCD) data. A 16-bit PCM stream with
+embedded HDCD codes is expanded into a 20-bit PCM stream.
+
+
The filter supports the Peak Extend and Low-level Gain Adjustment features
+of HDCD, and detects the Transient Filter flag.
+
+
+
ffmpeg -i HDCD16.flac -af hdcd OUT24.flac
+
+
+
When using the filter with wav, note the default encoding for wav is 16-bit,
+so the resulting 20-bit stream will be truncated back to 16-bit. Use something
+like -acodec pcm_s24le after the filter to get 24-bit PCM output.
+
+
ffmpeg -i HDCD16.wav -af hdcd OUT16.wav
+ffmpeg -i HDCD16.wav -af hdcd -c:a pcm_s24le OUT24.wav
+
+
+
The filter accepts the following options:
+
+
+- disable_autoconvert
+Disable any automatic format conversion or resampling in the filter graph.
+
+- process_stereo
+Process the stereo channels together. If target_gain does not match between
+channels, consider it invalid and use the last valid target_gain.
+
+- cdt_ms
+Set the code detect timer period in ms.
+
+- force_pe
+Always extend peaks above -3dBFS even if PE isn’t signaled.
+
+- analyze_mode
+Replace audio with a solid tone and adjust the amplitude to signal some
+specific aspect of the decoding process. The output file can be loaded in
+an audio editor alongside the original to aid analysis.
+
+analyze_mode=pe:force_pe=true can be used to see all samples above the PE level.
+
+Modes are:
+
+- ‘0, off’
+Disabled
+
- ‘1, lle’
+Gain adjustment level at each sample
+
- ‘2, pe’
+Samples where peak extend occurs
+
- ‘3, cdt’
+Samples where the code detect timer is active
+
- ‘4, tgm’
+Samples where the target gain does not match between channels
+
+
+
+
+
+
36.90 headphone
+
+
Apply head-related transfer functions (HRTFs) to create virtual
+loudspeakers around the user for binaural listening via headphones.
+The HRIRs are provided via additional streams, for each channel
+one stereo input stream is needed.
+
+
The filter accepts the following options:
+
+
+- map
+Set mapping of input streams for convolution.
+The argument is a ’|’-separated list of channel names in order as they
+are given as additional stream inputs for filter.
+This also specify number of input streams. Number of input streams
+must be not less than number of channels in first stream plus one.
+
+- gain
+Set gain applied to audio. Value is in dB. Default is 0.
+
+- type
+Set processing type. Can be time or freq. time is
+processing audio in time domain which is slow.
+freq is processing audio in frequency domain which is fast.
+Default is freq.
+
+- lfe
+Set custom gain for LFE channels. Value is in dB. Default is 0.
+
+- size
+Set size of frame in number of samples which will be processed at once.
+Default value is 1024. Allowed range is from 1024 to 96000.
+
+- hrir
+Set format of hrir stream.
+Default value is stereo. Alternative value is multich.
+If value is set to stereo, number of additional streams should
+be greater or equal to number of input channels in first input stream.
+Also each additional stream should have stereo number of channels.
+If value is set to multich, number of additional streams should
+be exactly one. Also number of input channels of additional stream
+should be equal or greater than twice number of channels of first input
+stream.
+
+
+
+
+
36.90.1 Examples
+
+
+- Full example using wav files as coefficients with amovie filters for 7.1 downmix,
+each amovie filter use stereo file with IR coefficients as input.
+The files give coefficients for each position of virtual loudspeaker:
+
+
ffmpeg -i input.wav
+-filter_complex "amovie=azi_270_ele_0_DFC.wav[sr];amovie=azi_90_ele_0_DFC.wav[sl];amovie=azi_225_ele_0_DFC.wav[br];amovie=azi_135_ele_0_DFC.wav[bl];amovie=azi_0_ele_0_DFC.wav,asplit[fc][lfe];amovie=azi_35_ele_0_DFC.wav[fl];amovie=azi_325_ele_0_DFC.wav[fr];[0:a][fl][fr][fc][lfe][bl][br][sl][sr]headphone=FL|FR|FC|LFE|BL|BR|SL|SR"
+output.wav
+
- Full example using wav files as coefficients with amovie filters for 7.1 downmix,
+but now in multich hrir format.
+
+
ffmpeg -i input.wav -filter_complex "amovie=minp.wav[hrirs];[0:a][hrirs]headphone=map=FL|FR|FC|LFE|BL|BR|SL|SR:hrir=multich"
+output.wav
+
+
+
+
+
+
36.91 highpass
+
+
Apply a high-pass filter with 3dB point frequency.
+The filter can be either single-pole, or double-pole (the default).
+The filter roll off at 6dB per pole per octave (20dB per pole per decade).
+
+
The filter accepts the following options:
+
+
+- frequency, f
+Set frequency in Hz. Default is 3000.
+
+- poles, p
+Set number of poles. Default is 2.
+
+- width_type, t
+Set method to specify band-width of filter.
+
+- h
+Hz
+
- q
+Q-Factor
+
- o
+octave
+
- s
+slope
+
- k
+kHz
+
+
+- width, w
+Specify the band-width of a filter in width_type units.
+Applies only to double-pole filter.
+The default is 0.707q and gives a Butterworth response.
+
+- mix, m
+How much to use filtered signal in output. Default is 1.
+Range is between 0 and 1.
+
+- channels, c
+Specify which channels to filter, by default all available are filtered.
+
+- normalize, n
+Normalize biquad coefficients, by default is disabled.
+Enabling it will normalize magnitude response at DC to 0dB.
+
+- transform, a
+Set transform type of IIR filter.
+
+- di
+- dii
+- tdi
+- tdii
+- latt
+- svf
+- zdf
+
+
+- precision, r
+Set precison of filtering.
+
+- auto
+Pick automatic sample format depending on surround filters.
+
- s16
+Always use signed 16-bit.
+
- s32
+Always use signed 32-bit.
+
- f32
+Always use float 32-bit.
+
- f64
+Always use float 64-bit.
+
+
+- block_size, b
+Set block size used for reverse IIR processing. If this value is set to high enough
+value (higher than impulse response length truncated when reaches near zero values) filtering
+will become linear phase otherwise if not big enough it will just produce nasty artifacts.
+
+Note that filter delay will be exactly this many samples when set to non-zero value.
+
+
+
+
+
36.91.1 Commands
+
+
This filter supports the following commands:
+
+- frequency, f
+Change highpass frequency.
+Syntax for the command is : "frequency"
+
+- width_type, t
+Change highpass width_type.
+Syntax for the command is : "width_type"
+
+- width, w
+Change highpass width.
+Syntax for the command is : "width"
+
+- mix, m
+Change highpass mix.
+Syntax for the command is : "mix"
+
+
+
+
+
+
36.92 join
+
+
Join multiple input streams into one multi-channel stream.
+
+
It accepts the following parameters:
+
+- inputs
+The number of input streams. It defaults to 2.
+
+- channel_layout
+The desired output channel layout. It defaults to stereo.
+
+- map
+Map channels from inputs to output. The argument is a ’|’-separated list of
+mappings, each in the input_idx.in_channel-out_channel
+form. input_idx is the 0-based index of the input stream. in_channel
+can be either the name of the input channel (e.g. FL for front left) or its
+index in the specified input stream. out_channel is the name of the output
+channel.
+
+
+
The filter will attempt to guess the mappings when they are not specified
+explicitly. It does so by first trying to find an unused matching input channel
+and if that fails it picks the first unused input channel.
+
+
Join 3 inputs (with properly set channel layouts):
+
+
ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
+
+
+
Build a 5.1 output from 6 single-channel streams:
+
+
ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
+'join=inputs=6:channel_layout=5.1:map=0.0-FL|1.0-FR|2.0-FC|3.0-SL|4.0-SR|5.0-LFE'
+out
+
+
+
+
+
36.93 ladspa
+
+
Load a LADSPA (Linux Audio Developer’s Simple Plugin API) plugin.
+
+
To enable compilation of this filter you need to configure FFmpeg with
+--enable-ladspa.
+
+
+- file, f
+Specifies the name of LADSPA plugin library to load. If the environment
+variable LADSPA_PATH is defined, the LADSPA plugin is searched in
+each one of the directories specified by the colon separated list in
+LADSPA_PATH, otherwise in the standard LADSPA paths, which are in
+this order: HOME/.ladspa/lib/, /usr/local/lib/ladspa/,
+/usr/lib/ladspa/.
+
+- plugin, p
+Specifies the plugin within the library. Some libraries contain only
+one plugin, but others contain many of them. If this is not set filter
+will list all available plugins within the specified library.
+
+- controls, c
+Set the ’|’ separated list of controls which are zero or more floating point
+values that determine the behavior of the loaded plugin (for example delay,
+threshold or gain).
+Controls need to be defined using the following syntax:
+c0=value0|c1=value1|c2=value2|..., where
+valuei is the value set on the i-th control.
+Alternatively they can be also defined using the following syntax:
+value0|value1|value2|..., where
+valuei is the value set on the i-th control.
+If controls is set to help, all available controls and
+their valid ranges are printed.
+
+- sample_rate, s
+Specify the sample rate, default to 44100. Only used if plugin have
+zero inputs.
+
+- nb_samples, n
+Set the number of samples per channel per each output frame, default
+is 1024. Only used if plugin have zero inputs.
+
+- duration, d
+Set the minimum duration of the sourced audio. See
+(ffmpeg-utils)the Time duration section in the ffmpeg-utils(1) manual
+for the accepted syntax.
+Note that the resulting duration may be greater than the specified duration,
+as the generated audio is always cut at the end of a complete frame.
+If not specified, or the expressed duration is negative, the audio is
+supposed to be generated forever.
+Only used if plugin have zero inputs.
+
+- latency, l
+Enable latency compensation, by default is disabled.
+Only used if plugin have inputs.
+
+
+
+
+
36.93.1 Examples
+
+
+- List all available plugins within amp (LADSPA example plugin) library:
+
+
+
- List all available controls and their valid ranges for
vcf_notch
+plugin from VCF library:
+
+
ladspa=f=vcf:p=vcf_notch:c=help
+
- Simulate low quality audio equipment using
Computer Music Toolkit (CMT)
+plugin library:
+
+
ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
+
- Add reverberation to the audio using TAP-plugins
+(Tom’s Audio Processing plugins):
+
+
ladspa=file=tap_reverb:tap_reverb
+
- Generate white noise, with 0.2 amplitude:
+
+
ladspa=file=cmt:noise_source_white:c=c0=.2
+
- Generate 20 bpm clicks using plugin
C* Click - Metronome from the
+C* Audio Plugin Suite (CAPS) library:
+
+
ladspa=file=caps:Click:c=c1=20'
+
- Apply
C* Eq10X2 - Stereo 10-band equaliser effect:
+
+
ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
+
- Increase volume by 20dB using fast lookahead limiter from Steve Harris
+
SWH Plugins collection:
+
+
ladspa=fast_lookahead_limiter_1913:fastLookaheadLimiter:20|0|2
+
- Attenuate low frequencies using Multiband EQ from Steve Harris
+
SWH Plugins collection:
+
+
ladspa=mbeq_1197:mbeq:-24|-24|-24|0|0|0|0|0|0|0|0|0|0|0|0
+
- Reduce stereo image using
Narrower from the C* Audio Plugin Suite
+(CAPS) library:
+
+
+ - Another white noise, now using
C* Audio Plugin Suite (CAPS) library:
+
+
+ - Some fractal noise, using
C* Audio Plugin Suite (CAPS) library:
+
+
ladspa=caps:Fractal:c=c1=1
+
- Dynamic volume normalization using
VLevel plugin:
+
+
ladspa=vlevel-ladspa:vlevel_mono
+
+
+
+
+
36.93.2 Commands
+
+
This filter supports the following commands:
+
+- cN
+Modify the N-th control value.
+
+If the specified value is not valid, it is ignored and prior one is kept.
+
+
+
+
+
+
36.94 loudnorm
+
+
EBU R128 loudness normalization. Includes both dynamic and linear normalization modes.
+Support for both single pass (livestreams, files) and double pass (files) modes.
+This algorithm can target IL, LRA, and maximum true peak. In dynamic mode, to accurately
+detect true peaks, the audio stream will be upsampled to 192 kHz.
+Use the -ar option or aresample filter to explicitly set an output sample rate.
+
+
The filter accepts the following options:
+
+
+- I, i
+Set integrated loudness target.
+Range is -70.0 - -5.0. Default value is -24.0.
+
+- LRA, lra
+Set loudness range target.
+Range is 1.0 - 50.0. Default value is 7.0.
+
+- TP, tp
+Set maximum true peak.
+Range is -9.0 - +0.0. Default value is -2.0.
+
+- measured_I, measured_i
+Measured IL of input file.
+Range is -99.0 - +0.0.
+
+- measured_LRA, measured_lra
+Measured LRA of input file.
+Range is 0.0 - 99.0.
+
+- measured_TP, measured_tp
+Measured true peak of input file.
+Range is -99.0 - +99.0.
+
+- measured_thresh
+Measured threshold of input file.
+Range is -99.0 - +0.0.
+
+- offset
+Set offset gain. Gain is applied before the true-peak limiter.
+Range is -99.0 - +99.0. Default is +0.0.
+
+- linear
+Normalize by linearly scaling the source audio.
+measured_I, measured_LRA, measured_TP,
+and measured_thresh must all be specified. Target LRA shouldn’t
+be lower than source LRA and the change in integrated loudness shouldn’t
+result in a true peak which exceeds the target TP. If any of these
+conditions aren’t met, normalization mode will revert to dynamic.
+Options are true or false. Default is true.
+
+- dual_mono
+Treat mono input files as "dual-mono". If a mono file is intended for playback
+on a stereo system, its EBU R128 measurement will be perceptually incorrect.
+If set to true, this option will compensate for this effect.
+Multi-channel input files are not affected by this option.
+Options are true or false. Default is false.
+
+- print_format
+Set print format for stats. Options are summary, json, or none.
+Default value is none.
+
+
+
+
+
36.95 lowpass
+
+
Apply a low-pass filter with 3dB point frequency.
+The filter can be either single-pole or double-pole (the default).
+The filter roll off at 6dB per pole per octave (20dB per pole per decade).
+
+
The filter accepts the following options:
+
+
+- frequency, f
+Set frequency in Hz. Default is 500.
+
+- poles, p
+Set number of poles. Default is 2.
+
+- width_type, t
+Set method to specify band-width of filter.
+
+- h
+Hz
+
- q
+Q-Factor
+
- o
+octave
+
- s
+slope
+
- k
+kHz
+
+
+- width, w
+Specify the band-width of a filter in width_type units.
+Applies only to double-pole filter.
+The default is 0.707q and gives a Butterworth response.
+
+- mix, m
+How much to use filtered signal in output. Default is 1.
+Range is between 0 and 1.
+
+- channels, c
+Specify which channels to filter, by default all available are filtered.
+
+- normalize, n
+Normalize biquad coefficients, by default is disabled.
+Enabling it will normalize magnitude response at DC to 0dB.
+
+- transform, a
+Set transform type of IIR filter.
+
+- di
+- dii
+- tdi
+- tdii
+- latt
+- svf
+- zdf
+
+
+- precision, r
+Set precison of filtering.
+
+- auto
+Pick automatic sample format depending on surround filters.
+
- s16
+Always use signed 16-bit.
+
- s32
+Always use signed 32-bit.
+
- f32
+Always use float 32-bit.
+
- f64
+Always use float 64-bit.
+
+
+- block_size, b
+Set block size used for reverse IIR processing. If this value is set to high enough
+value (higher than impulse response length truncated when reaches near zero values) filtering
+will become linear phase otherwise if not big enough it will just produce nasty artifacts.
+
+Note that filter delay will be exactly this many samples when set to non-zero value.
+
+
+
+
+
36.95.1 Examples
+
+- Lowpass only LFE channel, it LFE is not present it does nothing:
+
+
+
+
+
+
36.95.2 Commands
+
+
This filter supports the following commands:
+
+- frequency, f
+Change lowpass frequency.
+Syntax for the command is : "frequency"
+
+- width_type, t
+Change lowpass width_type.
+Syntax for the command is : "width_type"
+
+- width, w
+Change lowpass width.
+Syntax for the command is : "width"
+
+- mix, m
+Change lowpass mix.
+Syntax for the command is : "mix"
+
+
+
+
+
+
36.96 lv2
+
+
Load a LV2 (LADSPA Version 2) plugin.
+
+
To enable compilation of this filter you need to configure FFmpeg with
+--enable-lv2.
+
+
+- plugin, p
+Specifies the plugin URI. You may need to escape ’:’.
+
+- controls, c
+Set the ’|’ separated list of controls which are zero or more floating point
+values that determine the behavior of the loaded plugin (for example delay,
+threshold or gain).
+If controls is set to help, all available controls and
+their valid ranges are printed.
+
+- sample_rate, s
+Specify the sample rate, default to 44100. Only used if plugin have
+zero inputs.
+
+- nb_samples, n
+Set the number of samples per channel per each output frame, default
+is 1024. Only used if plugin have zero inputs.
+
+- duration, d
+Set the minimum duration of the sourced audio. See
+(ffmpeg-utils)the Time duration section in the ffmpeg-utils(1) manual
+for the accepted syntax.
+Note that the resulting duration may be greater than the specified duration,
+as the generated audio is always cut at the end of a complete frame.
+If not specified, or the expressed duration is negative, the audio is
+supposed to be generated forever.
+Only used if plugin have zero inputs.
+
+
+
+
+
36.96.1 Examples
+
+
+- Apply bass enhancer plugin from Calf:
+
+
lv2=p=http\\\\://calf.sourceforge.net/plugins/BassEnhancer:c=amount=2
+
- Apply vinyl plugin from Calf:
+
+
lv2=p=http\\\\://calf.sourceforge.net/plugins/Vinyl:c=drone=0.2|aging=0.5
+
- Apply bit crusher plugin from ArtyFX:
+
+
lv2=p=http\\\\://www.openavproductions.com/artyfx#bitta:c=crush=0.3
+
+
+
+
+
36.96.2 Commands
+
+
This filter supports all options that are exported by plugin as commands.
+
+
+
+
+
36.97 mcompand
+
Multiband Compress or expand the audio’s dynamic range.
+
+
The input audio is divided into bands using 4th order Linkwitz-Riley IIRs.
+This is akin to the crossover of a loudspeaker, and results in flat frequency
+response when absent compander action.
+
+
It accepts the following parameters:
+
+
+- args
+This option syntax is:
+attack,decay,[attack,decay..] soft-knee points crossover_frequency [delay [initial_volume [gain]]] | attack,decay ...
+For explanation of each item refer to compand filter documentation.
+
+
+
+
+
36.98 pan
+
+
Mix channels with specific gain levels. The filter accepts the output
+channel layout followed by a set of channels definitions.
+
+
This filter is also designed to efficiently remap the channels of an audio
+stream.
+
+
The filter accepts parameters of the form:
+"l|outdef|outdef|..."
+
+
+- l
+output channel layout or number of channels
+
+- outdef
+output channel specification, of the form:
+"out_name=[gain*]in_name[(+-)[gain*]in_name...]"
+
+- out_name
+output channel to define, either a channel name (FL, FR, etc.) or a channel
+number (c0, c1, etc.)
+
+- gain
+multiplicative coefficient for the channel, 1 leaving the volume unchanged
+
+- in_name
+input channel to use, see out_name for details; it is not possible to mix
+named and numbered input channels
+
+
+
If the ‘=’ in a channel specification is replaced by ‘<’, then the gains for
+that specification will be renormalized so that the total is 1, thus
+avoiding clipping noise.
+
+
+
+
36.98.1 Mixing examples
+
+
For example, if you want to down-mix from stereo to mono, but with a bigger
+factor for the left channel:
+
+
pan=1c|c0=0.9*c0+0.1*c1
+
+
+
A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
+7-channels surround:
+
+
pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
+
+
+
Note that ffmpeg integrates a default down-mix (and up-mix) system
+that should be preferred (see "-ac" option) unless you have very specific
+needs.
+
+
+
+
36.98.2 Remapping examples
+
+
The channel remapping will be effective if, and only if:
+
+
+- gain coefficients are zeroes or ones,
+
- only one input per channel output,
+
+
+
If all these conditions are satisfied, the filter will notify the user ("Pure
+channel mapping detected"), and use an optimized and lossless method to do the
+remapping.
+
+
For example, if you have a 5.1 source and want a stereo audio stream by
+dropping the extra channels:
+
+
pan="stereo| c0=FL | c1=FR"
+
+
+
Given the same source, you can also switch front left and front right channels
+and keep the input channel layout:
+
+
pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
+
+
+
If the input is a stereo audio stream, you can mute the front left channel (and
+still keep the stereo channel layout) with:
+
+
+
Still with a stereo audio stream input, you can copy the right channel in both
+front left and right:
+
+
pan="stereo| c0=FR | c1=FR"
+
+
+
+
+
+
36.99 replaygain
+
+
ReplayGain scanner filter. This filter takes an audio stream as an input and
+outputs it unchanged.
+At end of filtering it displays track_gain and track_peak.
+
+
The filter accepts the following exported read-only options:
+
+
+- track_gain
+Exported track gain in dB at end of stream.
+
+- track_peak
+Exported track peak at end of stream.
+
+
+
+
+
36.100 resample
+
+
Convert the audio sample format, sample rate and channel layout. It is
+not meant to be used directly.
+
+
+
+
36.101 rubberband
+
Apply time-stretching and pitch-shifting with librubberband.
+
+
To enable compilation of this filter, you need to configure FFmpeg with
+--enable-librubberband.
+
+
The filter accepts the following options:
+
+
+- tempo
+Set tempo scale factor.
+
+- pitch
+Set pitch scale factor.
+
+- transients
+Set transients detector.
+Possible values are:
+
+- crisp
+- mixed
+- smooth
+
+
+- detector
+Set detector.
+Possible values are:
+
+- compound
+- percussive
+- soft
+
+
+- phase
+Set phase.
+Possible values are:
+
+- laminar
+- independent
+
+
+- window
+Set processing window size.
+Possible values are:
+
+- standard
+- short
+- long
+
+
+- smoothing
+Set smoothing.
+Possible values are:
+
+- off
+- on
+
+
+- formant
+Enable formant preservation when shift pitching.
+Possible values are:
+
+- shifted
+- preserved
+
+
+- pitchq
+Set pitch quality.
+Possible values are:
+
+- quality
+- speed
+- consistency
+
+
+- channels
+Set channels.
+Possible values are:
+
+- apart
+- together
+
+
+
+
+
+
36.101.1 Commands
+
+
This filter supports the following commands:
+
+- tempo
+Change filter tempo scale factor.
+Syntax for the command is : "tempo"
+
+- pitch
+Change filter pitch scale factor.
+Syntax for the command is : "pitch"
+
+
+
+
+
+
36.102 sidechaincompress
+
+
This filter acts like normal compressor but has the ability to compress
+detected signal using second input signal.
+It needs two input streams and returns one output stream.
+First input stream will be processed depending on second stream signal.
+The filtered signal then can be filtered with other filters in later stages of
+processing. See pan and amerge filter.
+
+
The filter accepts the following options:
+
+
+- level_in
+Set input gain. Default is 1. Range is between 0.015625 and 64.
+
+- mode
+Set mode of compressor operation. Can be upward or downward.
+Default is downward.
+
+- threshold
+If a signal of second stream raises above this level it will affect the gain
+reduction of first stream.
+By default is 0.125. Range is between 0.00097563 and 1.
+
+- ratio
+Set a ratio about which the signal is reduced. 1:2 means that if the level
+raised 4dB above the threshold, it will be only 2dB above after the reduction.
+Default is 2. Range is between 1 and 20.
+
+- attack
+Amount of milliseconds the signal has to rise above the threshold before gain
+reduction starts. Default is 20. Range is between 0.01 and 2000.
+
+- release
+Amount of milliseconds the signal has to fall below the threshold before
+reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
+
+- makeup
+Set the amount by how much signal will be amplified after processing.
+Default is 1. Range is from 1 to 64.
+
+- knee
+Curve the sharp knee around the threshold to enter gain reduction more softly.
+Default is 2.82843. Range is between 1 and 8.
+
+- link
+Choose if the average level between all channels of side-chain stream
+or the louder(maximum) channel of side-chain stream affects the
+reduction. Default is average.
+
+- detection
+Should the exact signal be taken in case of peak or an RMS one in case
+of rms. Default is rms which is mainly smoother.
+
+- level_sc
+Set sidechain gain. Default is 1. Range is between 0.015625 and 64.
+
+- mix
+How much to use compressed signal in output. Default is 1.
+Range is between 0 and 1.
+
+
+
+
+
36.102.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
36.102.2 Examples
+
+
+- Full ffmpeg example taking 2 audio inputs, 1st input to be compressed
+depending on the signal of 2nd input and later compressed signal to be
+merged with 2nd input:
+
+
ffmpeg -i main.flac -i sidechain.flac -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress[compr];[compr][mix]amerge"
+
+
+
+
+
+
36.103 sidechaingate
+
+
A sidechain gate acts like a normal (wideband) gate but has the ability to
+filter the detected signal before sending it to the gain reduction stage.
+Normally a gate uses the full range signal to detect a level above the
+threshold.
+For example: If you cut all lower frequencies from your sidechain signal
+the gate will decrease the volume of your track only if not enough highs
+appear. With this technique you are able to reduce the resonation of a
+natural drum or remove "rumbling" of muted strokes from a heavily distorted
+guitar.
+It needs two input streams and returns one output stream.
+First input stream will be processed depending on second stream signal.
+
+
The filter accepts the following options:
+
+
+- level_in
+Set input level before filtering.
+Default is 1. Allowed range is from 0.015625 to 64.
+
+- mode
+Set the mode of operation. Can be upward or downward.
+Default is downward. If set to upward mode, higher parts of signal
+will be amplified, expanding dynamic range in upward direction.
+Otherwise, in case of downward lower parts of signal will be reduced.
+
+- range
+Set the level of gain reduction when the signal is below the threshold.
+Default is 0.06125. Allowed range is from 0 to 1.
+Setting this to 0 disables reduction and then filter behaves like expander.
+
+- threshold
+If a signal rises above this level the gain reduction is released.
+Default is 0.125. Allowed range is from 0 to 1.
+
+- ratio
+Set a ratio about which the signal is reduced.
+Default is 2. Allowed range is from 1 to 9000.
+
+- attack
+Amount of milliseconds the signal has to rise above the threshold before gain
+reduction stops.
+Default is 20 milliseconds. Allowed range is from 0.01 to 9000.
+
+- release
+Amount of milliseconds the signal has to fall below the threshold before the
+reduction is increased again. Default is 250 milliseconds.
+Allowed range is from 0.01 to 9000.
+
+- makeup
+Set amount of amplification of signal after processing.
+Default is 1. Allowed range is from 1 to 64.
+
+- knee
+Curve the sharp knee around the threshold to enter gain reduction more softly.
+Default is 2.828427125. Allowed range is from 1 to 8.
+
+- detection
+Choose if exact signal should be taken for detection or an RMS like one.
+Default is rms. Can be peak or rms.
+
+- link
+Choose if the average level between all channels or the louder channel affects
+the reduction.
+Default is average. Can be average or maximum.
+
+- level_sc
+Set sidechain gain. Default is 1. Range is from 0.015625 to 64.
+
+
+
+
+
36.103.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
36.104 silencedetect
+
+
Detect silence in an audio stream.
+
+
This filter logs a message when it detects that the input audio volume is less
+or equal to a noise tolerance value for a duration greater or equal to the
+minimum detected noise duration.
+
+
The printed times and duration are expressed in seconds. The
+lavfi.silence_start or lavfi.silence_start.X metadata key
+is set on the first frame whose timestamp equals or exceeds the detection
+duration and it contains the timestamp of the first frame of the silence.
+
+
The lavfi.silence_duration or lavfi.silence_duration.X
+and lavfi.silence_end or lavfi.silence_end.X metadata
+keys are set on the first frame after the silence. If mono is
+enabled, and each channel is evaluated separately, the .X
+suffixed keys are used, and X corresponds to the channel number.
+
+
The filter accepts the following options:
+
+
+- noise, n
+Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
+specified value) or amplitude ratio. Default is -60dB, or 0.001.
+
+- duration, d
+Set silence duration until notification (default is 2 seconds). See
+(ffmpeg-utils)the Time duration section in the ffmpeg-utils(1) manual
+for the accepted syntax.
+
+- mono, m
+Process each channel separately, instead of combined. By default is disabled.
+
+
+
+
+
36.104.1 Examples
+
+
+- Detect 5 seconds of silence with -50dB noise tolerance:
+
+
silencedetect=n=-50dB:d=5
+
- Complete example with
ffmpeg to detect silence with 0.0001 noise
+tolerance in silence.mp3:
+
+
ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
+
+
+
+
+
+
36.105 silenceremove
+
+
Remove silence from the beginning, middle or end of the audio.
+
+
The filter accepts the following options:
+
+
+- start_periods
+This value is used to indicate if audio should be trimmed at beginning of
+the audio. A value of zero indicates no silence should be trimmed from the
+beginning. When specifying a non-zero value, it trims audio up until it
+finds non-silence. Normally, when trimming silence from beginning of audio
+the start_periods will be 1 but it can be increased to higher
+values to trim all audio up to specific count of non-silence periods.
+Default value is 0.
+
+- start_duration
+Specify the amount of time that non-silence must be detected before it stops
+trimming audio. By increasing the duration, bursts of noises can be treated
+as silence and trimmed off. Default value is 0.
+
+- start_threshold
+This indicates what sample value should be treated as silence. For digital
+audio, a value of 0 may be fine but for audio recorded from analog,
+you may wish to increase the value to account for background noise.
+Can be specified in dB (in case "dB" is appended to the specified value)
+or amplitude ratio. Default value is 0.
+
+- start_silence
+Specify max duration of silence at beginning that will be kept after
+trimming. Default is 0, which is equal to trimming all samples detected
+as silence.
+
+- start_mode
+Specify mode of detection of silence end in start of multi-channel audio.
+Can be any or all. Default is any.
+With any, any sample that is detected as non-silence will cause
+stopped trimming of silence.
+With all, only if all channels are detected as non-silence will cause
+stopped trimming of silence.
+
+- stop_periods
+Set the count for trimming silence from the end of audio.
+To remove silence from the middle of a file, specify a stop_periods
+that is negative. This value is then treated as a positive value and is
+used to indicate the effect should restart processing as specified by
+start_periods, making it suitable for removing periods of silence
+in the middle of the audio.
+Default value is 0.
+
+- stop_duration
+Specify a duration of silence that must exist before audio is not copied any
+more. By specifying a higher duration, silence that is wanted can be left in
+the audio.
+Default value is 0.
+
+- stop_threshold
+This is the same as start_threshold but for trimming silence from
+the end of audio.
+Can be specified in dB (in case "dB" is appended to the specified value)
+or amplitude ratio. Default value is 0.
+
+- stop_silence
+Specify max duration of silence at end that will be kept after
+trimming. Default is 0, which is equal to trimming all samples detected
+as silence.
+
+- stop_mode
+Specify mode of detection of silence start in end of multi-channel audio.
+Can be any or all. Default is any.
+With any, any sample that is detected as non-silence will cause
+stopped trimming of silence.
+With all, only if all channels are detected as non-silence will cause
+stopped trimming of silence.
+
+- detection
+Set how is silence detected. Can be rms or peak. Second is faster
+and works better with digital silence which is exactly 0.
+Default value is rms.
+
+- window
+Set duration in number of seconds used to calculate size of window in number
+of samples for detecting silence.
+Default value is 0.02. Allowed range is from 0 to 10.
+
+
+
+
+
36.105.1 Examples
+
+
+- The following example shows how this filter can be used to start a recording
+that does not contain the delay at the start which usually occurs between
+pressing the record button and the start of the performance:
+
+
silenceremove=start_periods=1:start_duration=5:start_threshold=0.02
+
- Trim all silence encountered from beginning to end where there is more than 1
+second of silence in audio:
+
+
silenceremove=stop_periods=-1:stop_duration=1:stop_threshold=-90dB
+
- Trim all digital silence samples, using peak detection, from beginning to end
+where there is more than 0 samples of digital silence in audio and digital
+silence is detected in all channels at same positions in stream:
+
+
silenceremove=window=0:detection=peak:stop_mode=all:start_mode=all:stop_periods=-1:stop_threshold=0
+
+
+
+
+
+
36.106 sofalizer
+
+
SOFAlizer uses head-related transfer functions (HRTFs) to create virtual
+loudspeakers around the user for binaural listening via headphones (audio
+formats up to 9 channels supported).
+The HRTFs are stored in SOFA files (see http://www.sofacoustics.org/ for a database).
+SOFAlizer is developed at the Acoustics Research Institute (ARI) of the
+Austrian Academy of Sciences.
+
+
To enable compilation of this filter you need to configure FFmpeg with
+--enable-libmysofa.
+
+
The filter accepts the following options:
+
+
+- sofa
+Set the SOFA file used for rendering.
+
+- gain
+Set gain applied to audio. Value is in dB. Default is 0.
+
+- rotation
+Set rotation of virtual loudspeakers in deg. Default is 0.
+
+- elevation
+Set elevation of virtual speakers in deg. Default is 0.
+
+- radius
+Set distance in meters between loudspeakers and the listener with near-field
+HRTFs. Default is 1.
+
+- type
+Set processing type. Can be time or freq. time is
+processing audio in time domain which is slow.
+freq is processing audio in frequency domain which is fast.
+Default is freq.
+
+- speakers
+Set custom positions of virtual loudspeakers. Syntax for this option is:
+<CH> <AZIM> <ELEV>[|<CH> <AZIM> <ELEV>|...].
+Each virtual loudspeaker is described with short channel name following with
+azimuth and elevation in degrees.
+Each virtual loudspeaker description is separated by ’|’.
+For example to override front left and front right channel positions use:
+’speakers=FL 45 15|FR 345 15’.
+Descriptions with unrecognised channel names are ignored.
+
+- lfegain
+Set custom gain for LFE channels. Value is in dB. Default is 0.
+
+- framesize
+Set custom frame size in number of samples. Default is 1024.
+Allowed range is from 1024 to 96000. Only used if option ‘type’
+is set to freq.
+
+- normalize
+Should all IRs be normalized upon importing SOFA file.
+By default is enabled.
+
+- interpolate
+Should nearest IRs be interpolated with neighbor IRs if exact position
+does not match. By default is disabled.
+
+- minphase
+Minphase all IRs upon loading of SOFA file. By default is disabled.
+
+- anglestep
+Set neighbor search angle step. Only used if option interpolate is enabled.
+
+- radstep
+Set neighbor search radius step. Only used if option interpolate is enabled.
+
+
+
+
+
36.106.1 Examples
+
+
+- Using ClubFritz6 sofa file:
+
+
sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=1
+
- Using ClubFritz12 sofa file and bigger radius with small rotation:
+
+
sofalizer=sofa=/path/to/ClubFritz12.sofa:type=freq:radius=2:rotation=5
+
- Similar as above but with custom speaker positions for front left, front right, back left and back right
+and also with custom gain:
+
+
"sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=2:speakers=FL 45|FR 315|BL 135|BR 225:gain=28"
+
+
+
+
+
+
36.107 speechnorm
+
Speech Normalizer.
+
+
This filter expands or compresses each half-cycle of audio samples
+(local set of samples all above or all below zero and between two nearest zero crossings) depending
+on threshold value, so audio reaches target peak value under conditions controlled by below options.
+
+
The filter accepts the following options:
+
+
+- peak, p
+Set the expansion target peak value. This specifies the highest allowed absolute amplitude
+level for the normalized audio input. Default value is 0.95. Allowed range is from 0.0 to 1.0.
+
+- expansion, e
+Set the maximum expansion factor. Allowed range is from 1.0 to 50.0. Default value is 2.0.
+This option controls maximum local half-cycle of samples expansion. The maximum expansion
+would be such that local peak value reaches target peak value but never to surpass it and that
+ratio between new and previous peak value does not surpass this option value.
+
+- compression, c
+Set the maximum compression factor. Allowed range is from 1.0 to 50.0. Default value is 2.0.
+This option controls maximum local half-cycle of samples compression. This option is used
+only if threshold option is set to value greater than 0.0, then in such cases
+when local peak is lower or same as value set by threshold all samples belonging to
+that peak’s half-cycle will be compressed by current compression factor.
+
+- threshold, t
+Set the threshold value. Default value is 0.0. Allowed range is from 0.0 to 1.0.
+This option specifies which half-cycles of samples will be compressed and which will be expanded.
+Any half-cycle samples with their local peak value below or same as this option value will be
+compressed by current compression factor, otherwise, if greater than threshold value they will be
+expanded with expansion factor so that it could reach peak target value but never surpass it.
+
+- raise, r
+Set the expansion raising amount per each half-cycle of samples. Default value is 0.001.
+Allowed range is from 0.0 to 1.0. This controls how fast expansion factor is raised per
+each new half-cycle until it reaches expansion value.
+Setting this options too high may lead to distortions.
+
+- fall, f
+Set the compression raising amount per each half-cycle of samples. Default value is 0.001.
+Allowed range is from 0.0 to 1.0. This controls how fast compression factor is raised per
+each new half-cycle until it reaches compression value.
+
+- channels, h
+Specify which channels to filter, by default all available channels are filtered.
+
+- invert, i
+Enable inverted filtering, by default is disabled. This inverts interpretation of threshold
+option. When enabled any half-cycle of samples with their local peak value below or same as
+threshold option will be expanded otherwise it will be compressed.
+
+- link, l
+Link channels when calculating gain applied to each filtered channel sample, by default is disabled.
+When disabled each filtered channel gain calculation is independent, otherwise when this option
+is enabled the minimum of all possible gains for each filtered channel is used.
+
+- rms, m
+Set the expansion target RMS value. This specifies the highest allowed RMS level for the normalized
+audio input. Default value is 0.0, thus disabled. Allowed range is from 0.0 to 1.0.
+
+
+
+
+
36.107.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
36.107.2 Examples
+
+
+- Weak and slow amplification:
+
+
speechnorm=e=3:r=0.00001:l=1
+
- Moderate and slow amplification:
+
+
speechnorm=e=6.25:r=0.00001:l=1
+
- Strong and fast amplification:
+
+
speechnorm=e=12.5:r=0.0001:l=1
+
- Very strong and fast amplification:
+
+
speechnorm=e=25:r=0.0001:l=1
+
- Extreme and fast amplification:
+
+
speechnorm=e=50:r=0.0001:l=1
+
+
+
+
+
+
+
36.109 stereowiden
+
+
This filter enhance the stereo effect by suppressing signal common to both
+channels and by delaying the signal of left into right and vice versa,
+thereby widening the stereo effect.
+
+
The filter accepts the following options:
+
+
+- delay
+Time in milliseconds of the delay of left signal into right and vice versa.
+Default is 20 milliseconds.
+
+- feedback
+Amount of gain in delayed signal into right and vice versa. Gives a delay
+effect of left signal in right output and vice versa which gives widening
+effect. Default is 0.3.
+
+- crossfeed
+Cross feed of left into right with inverted phase. This helps in suppressing
+the mono. If the value is 1 it will cancel all the signal common to both
+channels. Default is 0.3.
+
+- drymix
+Set level of input signal of original channel. Default is 0.8.
+
+
+
+
+
36.109.1 Commands
+
+
This filter supports the all above options except delay as commands.
+
+
+
+
+
36.110 superequalizer
+
Apply 18 band equalizer.
+
+
The filter accepts the following options:
+
+- 1b
+Set 65Hz band gain.
+
- 2b
+Set 92Hz band gain.
+
- 3b
+Set 131Hz band gain.
+
- 4b
+Set 185Hz band gain.
+
- 5b
+Set 262Hz band gain.
+
- 6b
+Set 370Hz band gain.
+
- 7b
+Set 523Hz band gain.
+
- 8b
+Set 740Hz band gain.
+
- 9b
+Set 1047Hz band gain.
+
- 10b
+Set 1480Hz band gain.
+
- 11b
+Set 2093Hz band gain.
+
- 12b
+Set 2960Hz band gain.
+
- 13b
+Set 4186Hz band gain.
+
- 14b
+Set 5920Hz band gain.
+
- 15b
+Set 8372Hz band gain.
+
- 16b
+Set 11840Hz band gain.
+
- 17b
+Set 16744Hz band gain.
+
- 18b
+Set 20000Hz band gain.
+
+
+
+
+
36.111 surround
+
Apply audio surround upmix filter.
+
+
This filter allows to produce multichannel output from audio stream.
+
+
The filter accepts the following options:
+
+
+- chl_out
+Set output channel layout. By default, this is 5.1.
+
+See (ffmpeg-utils)the Channel Layout section in the ffmpeg-utils(1) manual
+for the required syntax.
+
+- chl_in
+Set input channel layout. By default, this is stereo.
+
+See (ffmpeg-utils)the Channel Layout section in the ffmpeg-utils(1) manual
+for the required syntax.
+
+- level_in
+Set input volume level. By default, this is 1.
+
+- level_out
+Set output volume level. By default, this is 1.
+
+- lfe
+Enable LFE channel output if output channel layout has it. By default, this is enabled.
+
+- lfe_low
+Set LFE low cut off frequency. By default, this is 128 Hz.
+
+- lfe_high
+Set LFE high cut off frequency. By default, this is 256 Hz.
+
+- lfe_mode
+Set LFE mode, can be add or sub. Default is add.
+In add mode, LFE channel is created from input audio and added to output.
+In sub mode, LFE channel is created from input audio and added to output but
+also all non-LFE output channels are subtracted with output LFE channel.
+
+- smooth
+Set temporal smoothness strength, used to gradually change factors when transforming
+stereo sound in time. Allowed range is from 0.0 to 1.0.
+Useful to improve output quality with focus option values greater than 0.0.
+Default is 0.0. Only values inside this range and without edges are effective.
+
+- angle
+Set angle of stereo surround transform, Allowed range is from 0 to 360.
+Default is 90.
+
+- focus
+Set focus of stereo surround transform, Allowed range is from -1 to 1.
+Default is 0.
+
+- fc_in
+Set front center input volume. By default, this is 1.
+
+- fc_out
+Set front center output volume. By default, this is 1.
+
+- fl_in
+Set front left input volume. By default, this is 1.
+
+- fl_out
+Set front left output volume. By default, this is 1.
+
+- fr_in
+Set front right input volume. By default, this is 1.
+
+- fr_out
+Set front right output volume. By default, this is 1.
+
+- sl_in
+Set side left input volume. By default, this is 1.
+
+- sl_out
+Set side left output volume. By default, this is 1.
+
+- sr_in
+Set side right input volume. By default, this is 1.
+
+- sr_out
+Set side right output volume. By default, this is 1.
+
+- bl_in
+Set back left input volume. By default, this is 1.
+
+- bl_out
+Set back left output volume. By default, this is 1.
+
+- br_in
+Set back right input volume. By default, this is 1.
+
+- br_out
+Set back right output volume. By default, this is 1.
+
+- bc_in
+Set back center input volume. By default, this is 1.
+
+- bc_out
+Set back center output volume. By default, this is 1.
+
+- lfe_in
+Set LFE input volume. By default, this is 1.
+
+- lfe_out
+Set LFE output volume. By default, this is 1.
+
+- allx
+Set spread usage of stereo image across X axis for all channels.
+Allowed range is from -1 to 15.
+By default this value is negative -1, and thus unused.
+
+- ally
+Set spread usage of stereo image across Y axis for all channels.
+Allowed range is from -1 to 15.
+By default this value is negative -1, and thus unused.
+
+- fcx, flx, frx, blx, brx, slx, srx, bcx
+Set spread usage of stereo image across X axis for each channel.
+Allowed range is from 0.06 to 15.
+By default this value is 0.5.
+
+- fcy, fly, fry, bly, bry, sly, sry, bcy
+Set spread usage of stereo image across Y axis for each channel.
+Allowed range is from 0.06 to 15.
+By default this value is 0.5.
+
+- win_size
+Set window size. Allowed range is from 1024 to 65536. Default size is 4096.
+
+- win_func
+Set window function.
+
+It accepts the following values:
+
+- ‘rect’
+- ‘bartlett’
+- ‘hann, hanning’
+- ‘hamming’
+- ‘blackman’
+- ‘welch’
+- ‘flattop’
+- ‘bharris’
+- ‘bnuttall’
+- ‘bhann’
+- ‘sine’
+- ‘nuttall’
+- ‘lanczos’
+- ‘gauss’
+- ‘tukey’
+- ‘dolph’
+- ‘cauchy’
+- ‘parzen’
+- ‘poisson’
+- ‘bohman’
+- ‘kaiser’
+
+Default is hann.
+
+- overlap
+Set window overlap. If set to 1, the recommended overlap for selected
+window function will be picked. Default is 0.5.
+
+
+
+
+
36.112 tiltshelf
+
+
Boost or cut the lower frequencies and cut or boost higher frequencies
+of the audio using a two-pole shelving filter with a response similar to
+that of a standard hi-fi’s tone-controls.
+This is also known as shelving equalisation (EQ).
+
+
The filter accepts the following options:
+
+
+- gain, g
+Give the gain at 0 Hz. Its useful range is about -20
+(for a large cut) to +20 (for a large boost).
+Beware of clipping when using a positive gain.
+
+- frequency, f
+Set the filter’s central frequency and so can be used
+to extend or reduce the frequency range to be boosted or cut.
+The default value is 3000 Hz.
+
+- width_type, t
+Set method to specify band-width of filter.
+
+- h
+Hz
+
- q
+Q-Factor
+
- o
+octave
+
- s
+slope
+
- k
+kHz
+
+
+- width, w
+Determine how steep is the filter’s shelf transition.
+
+- poles, p
+Set number of poles. Default is 2.
+
+- mix, m
+How much to use filtered signal in output. Default is 1.
+Range is between 0 and 1.
+
+- channels, c
+Specify which channels to filter, by default all available are filtered.
+
+- normalize, n
+Normalize biquad coefficients, by default is disabled.
+Enabling it will normalize magnitude response at DC to 0dB.
+
+- transform, a
+Set transform type of IIR filter.
+
+- di
+- dii
+- tdi
+- tdii
+- latt
+- svf
+- zdf
+
+
+- precision, r
+Set precison of filtering.
+
+- auto
+Pick automatic sample format depending on surround filters.
+
- s16
+Always use signed 16-bit.
+
- s32
+Always use signed 32-bit.
+
- f32
+Always use float 32-bit.
+
- f64
+Always use float 64-bit.
+
+
+- block_size, b
+Set block size used for reverse IIR processing. If this value is set to high enough
+value (higher than impulse response length truncated when reaches near zero values) filtering
+will become linear phase otherwise if not big enough it will just produce nasty artifacts.
+
+Note that filter delay will be exactly this many samples when set to non-zero value.
+
+
+
+
+
36.112.1 Commands
+
+
This filter supports some options as commands.
+
+
+
+
+
36.113 treble, highshelf
+
+
Boost or cut treble (upper) frequencies of the audio using a two-pole
+shelving filter with a response similar to that of a standard
+hi-fi’s tone-controls. This is also known as shelving equalisation (EQ).
+
+
The filter accepts the following options:
+
+
+- gain, g
+Give the gain at whichever is the lower of ~22 kHz and the
+Nyquist frequency. Its useful range is about -20 (for a large cut)
+to +20 (for a large boost). Beware of clipping when using a positive gain.
+
+- frequency, f
+Set the filter’s central frequency and so can be used
+to extend or reduce the frequency range to be boosted or cut.
+The default value is 3000 Hz.
+
+- width_type, t
+Set method to specify band-width of filter.
+
+- h
+Hz
+
- q
+Q-Factor
+
- o
+octave
+
- s
+slope
+
- k
+kHz
+
+
+- width, w
+Determine how steep is the filter’s shelf transition.
+
+- poles, p
+Set number of poles. Default is 2.
+
+- mix, m
+How much to use filtered signal in output. Default is 1.
+Range is between 0 and 1.
+
+- channels, c
+Specify which channels to filter, by default all available are filtered.
+
+- normalize, n
+Normalize biquad coefficients, by default is disabled.
+Enabling it will normalize magnitude response at DC to 0dB.
+
+- transform, a
+Set transform type of IIR filter.
+
+- di
+- dii
+- tdi
+- tdii
+- latt
+- svf
+- zdf
+
+
+- precision, r
+Set precison of filtering.
+
+- auto
+Pick automatic sample format depending on surround filters.
+
- s16
+Always use signed 16-bit.
+
- s32
+Always use signed 32-bit.
+
- f32
+Always use float 32-bit.
+
- f64
+Always use float 64-bit.
+
+
+- block_size, b
+Set block size used for reverse IIR processing. If this value is set to high enough
+value (higher than impulse response length truncated when reaches near zero values) filtering
+will become linear phase otherwise if not big enough it will just produce nasty artifacts.
+
+Note that filter delay will be exactly this many samples when set to non-zero value.
+
+
+
+
+
36.113.1 Commands
+
+
This filter supports the following commands:
+
+- frequency, f
+Change treble frequency.
+Syntax for the command is : "frequency"
+
+- width_type, t
+Change treble width_type.
+Syntax for the command is : "width_type"
+
+- width, w
+Change treble width.
+Syntax for the command is : "width"
+
+- gain, g
+Change treble gain.
+Syntax for the command is : "gain"
+
+- mix, m
+Change treble mix.
+Syntax for the command is : "mix"
+
+
+
+
+
+
36.114 tremolo
+
+
Sinusoidal amplitude modulation.
+
+
The filter accepts the following options:
+
+
+- f
+Modulation frequency in Hertz. Modulation frequencies in the subharmonic range
+(20 Hz or lower) will result in a tremolo effect.
+This filter may also be used as a ring modulator by specifying
+a modulation frequency higher than 20 Hz.
+Range is 0.1 - 20000.0. Default value is 5.0 Hz.
+
+- d
+Depth of modulation as a percentage. Range is 0.0 - 1.0.
+Default value is 0.5.
+
+
+
+
+
36.115 vibrato
+
+
Sinusoidal phase modulation.
+
+
The filter accepts the following options:
+
+
+- f
+Modulation frequency in Hertz.
+Range is 0.1 - 20000.0. Default value is 5.0 Hz.
+
+- d
+Depth of modulation as a percentage. Range is 0.0 - 1.0.
+Default value is 0.5.
+
+
+
+
+
36.116 virtualbass
+
+
Apply audio Virtual Bass filter.
+
+
This filter accepts stereo input and produce stereo with LFE (2.1) channels output.
+The newly produced LFE channel have enhanced virtual bass originally obtained from both stereo channels.
+This filter outputs front left and front right channels unchanged as available in stereo input.
+
+
The filter accepts the following options:
+
+
+- cutoff
+Set the virtual bass cutoff frequency. Default value is 250 Hz.
+Allowed range is from 100 to 500 Hz.
+
+- strength
+Set the virtual bass strength. Allowed range is from 0.5 to 3.
+Default value is 3.
+
+
+
+
+
36.117 volume
+
+
Adjust the input audio volume.
+
+
It accepts the following parameters:
+
+- volume
+Set audio volume expression.
+
+Output values are clipped to the maximum value.
+
+The output audio volume is given by the relation:
+
+
output_volume = volume * input_volume
+
The default value for volume is "1.0".
+
+- precision
+This parameter represents the mathematical precision.
+
+It determines which input sample formats will be allowed, which affects the
+precision of the volume scaling.
+
+
+- fixed
+8-bit fixed-point; this limits input sample format to U8, S16, and S32.
+
- float
+32-bit floating-point; this limits input sample format to FLT. (default)
+
- double
+64-bit floating-point; this limits input sample format to DBL.
+
+
+- replaygain
+Choose the behaviour on encountering ReplayGain side data in input frames.
+
+
+- drop
+Remove ReplayGain side data, ignoring its contents (the default).
+
+- ignore
+Ignore ReplayGain side data, but leave it in the frame.
+
+- track
+Prefer the track gain, if present.
+
+- album
+Prefer the album gain, if present.
+
+
+- replaygain_preamp
+Pre-amplification gain in dB to apply to the selected replaygain gain.
+
+Default value for replaygain_preamp is 0.0.
+
+- replaygain_noclip
+Prevent clipping by limiting the gain applied.
+
+Default value for replaygain_noclip is 1.
+
+- eval
+Set when the volume expression is evaluated.
+
+It accepts the following values:
+
+- ‘once’
+only evaluate expression once during the filter initialization, or
+when the ‘volume’ command is sent
+
+- ‘frame’
+evaluate expression for each incoming frame
+
+
+Default value is ‘once’.
+
+
+
The volume expression can contain the following parameters.
+
+
+- n
+frame number (starting at zero)
+
- nb_channels
+number of channels
+
- nb_consumed_samples
+number of samples consumed by the filter
+
- nb_samples
+number of samples in the current frame
+
- pos
+original frame position in the file; deprecated, do not use
+
- pts
+frame PTS
+
- sample_rate
+sample rate
+
- startpts
+PTS at start of stream
+
- startt
+time at start of stream
+
- t
+frame time
+
- tb
+timestamp timebase
+
- volume
+last set volume value
+
+
+
Note that when eval is set to ‘once’ only the
+sample_rate and tb variables are available, all other
+variables will evaluate to NAN.
+
+
+
+
36.117.1 Commands
+
+
This filter supports the following commands:
+
+- volume
+Modify the volume expression.
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
36.117.2 Examples
+
+
+
+
+
+
+
36.118 volumedetect
+
+
Detect the volume of the input video.
+
+
The filter has no parameters. It supports only 16-bit signed integer samples,
+so the input will be converted when needed. Statistics about the volume will
+be printed in the log when the input stream end is reached.
+
+
In particular it will show the mean volume (root mean square), maximum
+volume (on a per-sample basis), and the beginning of a histogram of the
+registered volume values (from the maximum value to a cumulated 1/1000 of
+the samples).
+
+
All volumes are in decibels relative to the maximum PCM value.
+
+
+
+
36.118.1 Examples
+
+
Here is an excerpt of the output:
+
+
[Parsed_volumedetect_0 0xa23120] mean_volume: -27 dB
+[Parsed_volumedetect_0 0xa23120] max_volume: -4 dB
+[Parsed_volumedetect_0 0xa23120] histogram_4db: 6
+[Parsed_volumedetect_0 0xa23120] histogram_5db: 62
+[Parsed_volumedetect_0 0xa23120] histogram_6db: 286
+[Parsed_volumedetect_0 0xa23120] histogram_7db: 1042
+[Parsed_volumedetect_0 0xa23120] histogram_8db: 2551
+[Parsed_volumedetect_0 0xa23120] histogram_9db: 4609
+[Parsed_volumedetect_0 0xa23120] histogram_10db: 8409
+
+
+
It means that:
+
+- The mean square energy is approximately -27 dB, or 10^-2.7.
+
- The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
+
- There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
+
+
+
In other words, raising the volume by +4 dB does not cause any clipping,
+raising it by +5 dB causes clipping for 6 samples, etc.
+
+
+
+
+
+
39 Video Filters
+
+
When you configure your FFmpeg build, you can disable any of the
+existing filters using --disable-filters.
+The configure output will show the video filters included in your
+build.
+
+
Below is a description of the currently available video filters.
+
+
+
+
39.1 addroi
+
+
Mark a region of interest in a video frame.
+
+
The frame data is passed through unchanged, but metadata is attached
+to the frame indicating regions of interest which can affect the
+behaviour of later encoding. Multiple regions can be marked by
+applying the filter multiple times.
+
+
+- x
+Region distance in pixels from the left edge of the frame.
+
- y
+Region distance in pixels from the top edge of the frame.
+
- w
+Region width in pixels.
+
- h
+Region height in pixels.
+
+The parameters x, y, w and h are expressions,
+and may contain the following variables:
+
+- iw
+Width of the input frame.
+
- ih
+Height of the input frame.
+
+
+- qoffset
+Quantisation offset to apply within the region.
+
+This must be a real value in the range -1 to +1. A value of zero
+indicates no quality change. A negative value asks for better quality
+(less quantisation), while a positive value asks for worse quality
+(greater quantisation).
+
+The range is calibrated so that the extreme values indicate the
+largest possible offset - if the rest of the frame is encoded with the
+worst possible quality, an offset of -1 indicates that this region
+should be encoded with the best possible quality anyway. Intermediate
+values are then interpolated in some codec-dependent way.
+
+For example, in 10-bit H.264 the quantisation parameter varies between
+-12 and 51. A typical qoffset value of -1/10 therefore indicates that
+this region should be encoded with a QP around one-tenth of the full
+range better than the rest of the frame. So, if most of the frame
+were to be encoded with a QP of around 30, this region would get a QP
+of around 24 (an offset of approximately -1/10 * (51 - -12) = -6.3).
+An extreme value of -1 would indicate that this region should be
+encoded with the best possible quality regardless of the treatment of
+the rest of the frame - that is, should be encoded at a QP of -12.
+
- clear
+If set to true, remove any existing regions of interest marked on the
+frame before adding the new one.
+
+
+
+
+
39.1.1 Examples
+
+
+- Mark the centre quarter of the frame as interesting.
+
+
addroi=iw/4:ih/4:iw/2:ih/2:-1/10
+
- Mark the 100-pixel-wide region on the left edge of the frame as very
+uninteresting (to be encoded at much lower quality than the rest of
+the frame).
+
+
addroi=0:0:100:ih:+1/5
+
+
+
+
+
+
+
39.3 alphamerge
+
+
Add or replace the alpha component of the primary input with the
+grayscale value of a second input. This is intended for use with
+alphaextract to allow the transmission or storage of frame
+sequences that have alpha in a format that doesn’t support an alpha
+channel.
+
+
For example, to reconstruct full frames from a normal YUV-encoded video
+and a separate video created with alphaextract, you might use:
+
+
movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
+
+
+
+
+
39.4 amplify
+
+
Amplify differences between current pixel and pixels of adjacent frames in
+same pixel location.
+
+
This filter accepts the following options:
+
+
+- radius
+Set frame radius. Default is 2. Allowed range is from 1 to 63.
+For example radius of 3 will instruct filter to calculate average of 7 frames.
+
+- factor
+Set factor to amplify difference. Default is 2. Allowed range is from 0 to 65535.
+
+- threshold
+Set threshold for difference amplification. Any difference greater or equal to
+this value will not alter source pixel. Default is 10.
+Allowed range is from 0 to 65535.
+
+- tolerance
+Set tolerance for difference amplification. Any difference lower to
+this value will not alter source pixel. Default is 0.
+Allowed range is from 0 to 65535.
+
+- low
+Set lower limit for changing source pixel. Default is 65535. Allowed range is from 0 to 65535.
+This option controls maximum possible value that will decrease source pixel value.
+
+- high
+Set high limit for changing source pixel. Default is 65535. Allowed range is from 0 to 65535.
+This option controls maximum possible value that will increase source pixel value.
+
+- planes
+Set which planes to filter. Default is all. Allowed range is from 0 to 15.
+
+
+
+
+
39.4.1 Commands
+
+
This filter supports the following commands that corresponds to option of same name:
+
+- factor
+- threshold
+- tolerance
+- low
+- high
+- planes
+
+
+
+
+
+
39.5 ass
+
+
Same as the subtitles filter, except that it doesn’t require libavcodec
+and libavformat to work. On the other hand, it is limited to ASS (Advanced
+Substation Alpha) subtitles files.
+
+
This filter accepts the following option in addition to the common options from
+the subtitles filter:
+
+
+- shaping
+Set the shaping engine
+
+Available values are:
+
+- ‘auto’
+The default libass shaping engine, which is the best available.
+
- ‘simple’
+Fast, font-agnostic shaper that can do only substitutions
+
- ‘complex’
+Slower shaper using OpenType for substitutions and positioning
+
+
+The default is auto.
+
+
+
+
+
39.6 atadenoise
+
Apply an Adaptive Temporal Averaging Denoiser to the video input.
+
+
The filter accepts the following options:
+
+
+- 0a
+Set threshold A for 1st plane. Default is 0.02.
+Valid range is 0 to 0.3.
+
+- 0b
+Set threshold B for 1st plane. Default is 0.04.
+Valid range is 0 to 5.
+
+- 1a
+Set threshold A for 2nd plane. Default is 0.02.
+Valid range is 0 to 0.3.
+
+- 1b
+Set threshold B for 2nd plane. Default is 0.04.
+Valid range is 0 to 5.
+
+- 2a
+Set threshold A for 3rd plane. Default is 0.02.
+Valid range is 0 to 0.3.
+
+- 2b
+Set threshold B for 3rd plane. Default is 0.04.
+Valid range is 0 to 5.
+
+Threshold A is designed to react on abrupt changes in the input signal and
+threshold B is designed to react on continuous changes in the input signal.
+
+- s
+Set number of frames filter will use for averaging. Default is 9. Must be odd
+number in range [5, 129].
+
+- p
+Set what planes of frame filter will use for averaging. Default is all.
+
+- a
+Set what variant of algorithm filter will use for averaging. Default is p parallel.
+Alternatively can be set to s serial.
+
+Parallel can be faster then serial, while other way around is never true.
+Parallel will abort early on first change being greater then thresholds, while serial
+will continue processing other side of frames if they are equal or below thresholds.
+
+- 0s
+- 1s
+- 2s
+Set sigma for 1st plane, 2nd plane or 3rd plane. Default is 32767.
+Valid range is from 0 to 32767.
+This options controls weight for each pixel in radius defined by size.
+Default value means every pixel have same weight.
+Setting this option to 0 effectively disables filtering.
+
+
+
+
+
39.6.1 Commands
+
This filter supports same commands as options except option s.
+The command accepts the same syntax of the corresponding option.
+
+
+
+
+
39.7 avgblur
+
+
Apply average blur filter.
+
+
The filter accepts the following options:
+
+
+- sizeX
+Set horizontal radius size.
+
+- planes
+Set which planes to filter. By default all planes are filtered.
+
+- sizeY
+Set vertical radius size, if zero it will be same as sizeX.
+Default is 0.
+
+
+
+
+
39.7.1 Commands
+
This filter supports same commands as options.
+The command accepts the same syntax of the corresponding option.
+
+
If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
39.8 backgroundkey
+
+
Turns a static background into transparency.
+
+
The filter accepts the following option:
+
+
+- threshold
+Threshold for scene change detection.
+
- similarity
+Similarity percentage with the background.
+
- blend
+Set the blend amount for pixels that are not similar.
+
+
+
+
+
39.8.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.9 bbox
+
+
Compute the bounding box for the non-black pixels in the input frame
+luminance plane.
+
+
This filter computes the bounding box containing all the pixels with a
+luminance value greater than the minimum allowed value.
+The parameters describing the bounding box are printed on the filter
+log.
+
+
The filter accepts the following option:
+
+
+- min_val
+Set the minimal luminance value. Default is 16.
+
+
+
+
+
39.9.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.10 bilateral
+
Apply bilateral filter, spatial smoothing while preserving edges.
+
+
The filter accepts the following options:
+
+- sigmaS
+Set sigma of gaussian function to calculate spatial weight.
+Allowed range is 0 to 512. Default is 0.1.
+
+- sigmaR
+Set sigma of gaussian function to calculate range weight.
+Allowed range is 0 to 1. Default is 0.1.
+
+- planes
+Set planes to filter. Default is first only.
+
+
+
+
+
39.10.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.11 bilateral_cuda
+
CUDA accelerated bilateral filter, an edge preserving filter.
+This filter is mathematically accurate thanks to the use of GPU acceleration.
+For best output quality, use one to one chroma subsampling, i.e. yuv444p format.
+
+
The filter accepts the following options:
+
+- sigmaS
+Set sigma of gaussian function to calculate spatial weight, also called sigma space.
+Allowed range is 0.1 to 512. Default is 0.1.
+
+- sigmaR
+Set sigma of gaussian function to calculate color range weight, also called sigma color.
+Allowed range is 0.1 to 512. Default is 0.1.
+
+- window_size
+Set window size of the bilateral function to determine the number of neighbours to loop on.
+If the number entered is even, one will be added automatically.
+Allowed range is 1 to 255. Default is 1.
+
+
+
+
39.11.1 Examples
+
+
+- Apply the bilateral filter on a video.
+
+
+
./ffmpeg -v verbose \
+-hwaccel cuda -hwaccel_output_format cuda -i input.mp4 \
+-init_hw_device cuda \
+-filter_complex \
+" \
+[0:v]scale_cuda=format=yuv444p[scaled_video];
+[scaled_video]bilateral_cuda=window_size=9:sigmaS=3.0:sigmaR=50.0" \
+-an -sn -c:v h264_nvenc -cq 20 out.mp4
+
+
+
+
+
+
39.12 bitplanenoise
+
+
Show and measure bit plane noise.
+
+
The filter accepts the following options:
+
+
+- bitplane
+Set which plane to analyze. Default is 1.
+
+- filter
+Filter out noisy pixels from bitplane set above.
+Default is disabled.
+
+
+
+
+
39.13 blackdetect
+
+
Detect video intervals that are (almost) completely black. Can be
+useful to detect chapter transitions, commercials, or invalid
+recordings.
+
+
The filter outputs its detection analysis to both the log as well as
+frame metadata. If a black segment of at least the specified minimum
+duration is found, a line with the start and end timestamps as well
+as duration is printed to the log with level info. In addition,
+a log line with level debug is printed per frame showing the
+black amount detected for that frame.
+
+
The filter also attaches metadata to the first frame of a black
+segment with key lavfi.black_start and to the first frame
+after the black segment ends with key lavfi.black_end. The
+value is the frame’s timestamp. This metadata is added regardless
+of the minimum duration specified.
+
+
The filter accepts the following options:
+
+
+- black_min_duration, d
+Set the minimum detected black duration expressed in seconds. It must
+be a non-negative floating point number.
+
+Default value is 2.0.
+
+- picture_black_ratio_th, pic_th
+Set the threshold for considering a picture "black".
+Express the minimum value for the ratio:
+
+
nb_black_pixels / nb_pixels
+
for which a picture is considered black.
+Default value is 0.98.
+
+- pixel_black_th, pix_th
+Set the threshold for considering a pixel "black".
+
+The threshold expresses the maximum pixel luminance value for which a
+pixel is considered "black". The provided value is scaled according to
+the following equation:
+
+
absolute_threshold = luminance_minimum_value + pixel_black_th * luminance_range_size
+
luminance_range_size and luminance_minimum_value depend on
+the input video format, the range is [0-255] for YUV full-range
+formats and [16-235] for YUV non full-range formats.
+
+Default value is 0.10.
+
+
+
The following example sets the maximum pixel threshold to the minimum
+value, and detects only black intervals of 2 or more seconds:
+
+
blackdetect=d=2:pix_th=0.00
+
+
+
+
+
39.14 blackframe
+
+
Detect frames that are (almost) completely black. Can be useful to
+detect chapter transitions or commercials. Output lines consist of
+the frame number of the detected frame, the percentage of blackness,
+the position in the file if known or -1 and the timestamp in seconds.
+
+
In order to display the output lines, you need to set the loglevel at
+least to the AV_LOG_INFO value.
+
+
This filter exports frame metadata lavfi.blackframe.pblack.
+The value represents the percentage of pixels in the picture that
+are below the threshold value.
+
+
It accepts the following parameters:
+
+
+- amount
+The percentage of the pixels that have to be below the threshold; it defaults to
+98.
+
+- threshold, thresh
+The threshold below which a pixel value is considered black; it defaults to
+32.
+
+
+
+
+
+
39.15 blend
+
+
Blend two video frames into each other.
+
+
The blend filter takes two input streams and outputs one
+stream, the first input is the "top" layer and second input is
+"bottom" layer. By default, the output terminates when the longest input terminates.
+
+
The tblend (time blend) filter takes two consecutive frames
+from one single stream, and outputs the result obtained by blending
+the new frame on top of the old frame.
+
+
A description of the accepted options follows.
+
+
+- c0_mode
+- c1_mode
+- c2_mode
+- c3_mode
+- all_mode
+Set blend mode for specific pixel component or all pixel components in case
+of all_mode. Default value is normal.
+
+Available values for component modes are:
+
+- ‘addition’
+- ‘and’
+- ‘average’
+- ‘bleach’
+- ‘burn’
+- ‘darken’
+- ‘difference’
+- ‘divide’
+- ‘dodge’
+- ‘exclusion’
+- ‘extremity’
+- ‘freeze’
+- ‘geometric’
+- ‘glow’
+- ‘grainextract’
+- ‘grainmerge’
+- ‘hardlight’
+- ‘hardmix’
+- ‘hardoverlay’
+- ‘harmonic’
+- ‘heat’
+- ‘interpolate’
+- ‘lighten’
+- ‘linearlight’
+- ‘multiply’
+- ‘multiply128’
+- ‘negation’
+- ‘normal’
+- ‘or’
+- ‘overlay’
+- ‘phoenix’
+- ‘pinlight’
+- ‘reflect’
+- ‘screen’
+- ‘softdifference’
+- ‘softlight’
+- ‘stain’
+- ‘subtract’
+- ‘vividlight’
+- ‘xor’
+
+
+- c0_opacity
+- c1_opacity
+- c2_opacity
+- c3_opacity
+- all_opacity
+Set blend opacity for specific pixel component or all pixel components in case
+of all_opacity. Only used in combination with pixel component blend modes.
+
+- c0_expr
+- c1_expr
+- c2_expr
+- c3_expr
+- all_expr
+Set blend expression for specific pixel component or all pixel components in case
+of all_expr. Note that related mode options will be ignored if those are set.
+
+The expressions can use the following variables:
+
+
+- N
+The sequential number of the filtered frame, starting from 0.
+
+- X
+- Y
+the coordinates of the current sample
+
+- W
+- H
+the width and height of currently filtered plane
+
+- SW
+- SH
+Width and height scale for the plane being filtered. It is the
+ratio between the dimensions of the current plane to the luma plane,
+e.g. for a yuv420p frame, the values are 1,1 for
+the luma plane and 0.5,0.5 for the chroma planes.
+
+- T
+Time of the current frame, expressed in seconds.
+
+- TOP, A
+Value of pixel component at current location for first video frame (top layer).
+
+- BOTTOM, B
+Value of pixel component at current location for second video frame (bottom layer).
+
+
+
+
The blend filter also supports the framesync options.
+
+
+
+
39.15.1 Examples
+
+
+- Apply transition from bottom layer to top layer in first 10 seconds:
+
+
blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
+
- Apply linear horizontal transition from top layer to bottom layer:
+
+
blend=all_expr='A*(X/W)+B*(1-X/W)'
+
- Apply 1x1 checkerboard effect:
+
+
blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
+
- Apply uncover left effect:
+
+
blend=all_expr='if(gte(N*SW+X,W),A,B)'
+
- Apply uncover down effect:
+
+
blend=all_expr='if(gte(Y-N*SH,0),A,B)'
+
- Apply uncover up-left effect:
+
+
blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
+
- Split diagonally video and shows top and bottom layer on each side:
+
+
blend=all_expr='if(gt(X,Y*(W/H)),A,B)'
+
- Display differences between the current and the previous frame:
+
+
tblend=all_mode=grainextract
+
+
+
+
+
39.15.2 Commands
+
This filter supports same commands as options.
+
+
+
+
+
39.16 blockdetect
+
+
Determines blockiness of frames without altering the input frames.
+
+
Based on Remco Muijs and Ihor Kirenko: "A no-reference blocking artifact measure for adaptive video processing." 2005 13th European signal processing conference.
+
+
The filter accepts the following options:
+
+
+- period_min
+- period_max
+Set minimum and maximum values for determining pixel grids (periods).
+Default values are [3,24].
+
+- planes
+Set planes to filter. Default is first only.
+
+
+
+
+
39.16.1 Examples
+
+
+- Determine blockiness for the first plane and search for periods within [8,32]:
+
+
blockdetect=period_min=8:period_max=32:planes=1
+
+
+
+
+
+
39.17 blurdetect
+
+
Determines blurriness of frames without altering the input frames.
+
+
Based on Marziliano, Pina, et al. "A no-reference perceptual blur metric."
+Allows for a block-based abbreviation.
+
+
The filter accepts the following options:
+
+
+- low
+- high
+Set low and high threshold values used by the Canny thresholding
+algorithm.
+
+The high threshold selects the "strong" edge pixels, which are then
+connected through 8-connectivity with the "weak" edge pixels selected
+by the low threshold.
+
+low and high threshold values must be chosen in the range
+[0,1], and low should be lesser or equal to high.
+
+Default value for low is 20/255, and default value for high
+is 50/255.
+
+- radius
+Define the radius to search around an edge pixel for local maxima.
+
+- block_pct
+Determine blurriness only for the most significant blocks, given in percentage.
+
+- block_width
+Determine blurriness for blocks of width block_width. If set to any value smaller 1, no blocks are used and the whole image is processed as one no matter of block_height.
+
+- block_height
+Determine blurriness for blocks of height block_height. If set to any value smaller 1, no blocks are used and the whole image is processed as one no matter of block_width.
+
+- planes
+Set planes to filter. Default is first only.
+
+
+
+
+
39.17.1 Examples
+
+
+- Determine blur for 80% of most significant 32x32 blocks:
+
+
blurdetect=block_width=32:block_height=32:block_pct=80
+
+
+
+
+
+
39.18 bm3d
+
+
Denoise frames using Block-Matching 3D algorithm.
+
+
The filter accepts the following options.
+
+
+- sigma
+Set denoising strength. Default value is 1.
+Allowed range is from 0 to 999.9.
+The denoising algorithm is very sensitive to sigma, so adjust it
+according to the source.
+
+- block
+Set local patch size. This sets dimensions in 2D.
+
+- bstep
+Set sliding step for processing blocks. Default value is 4.
+Allowed range is from 1 to 64.
+Smaller values allows processing more reference blocks and is slower.
+
+- group
+Set maximal number of similar blocks for 3rd dimension. Default value is 1.
+When set to 1, no block matching is done. Larger values allows more blocks
+in single group.
+Allowed range is from 1 to 256.
+
+- range
+Set radius for search block matching. Default is 9.
+Allowed range is from 1 to INT32_MAX.
+
+- mstep
+Set step between two search locations for block matching. Default is 1.
+Allowed range is from 1 to 64. Smaller is slower.
+
+- thmse
+Set threshold of mean square error for block matching. Valid range is 0 to
+INT32_MAX.
+
+- hdthr
+Set thresholding parameter for hard thresholding in 3D transformed domain.
+Larger values results in stronger hard-thresholding filtering in frequency
+domain.
+
+- estim
+Set filtering estimation mode. Can be basic or final.
+Default is basic.
+
+- ref
+If enabled, filter will use 2nd stream for block matching.
+Default is disabled for basic value of estim option,
+and always enabled if value of estim is final.
+
+- planes
+Set planes to filter. Default is all available except alpha.
+
+
+
+
+
39.18.1 Examples
+
+
+- Basic filtering with bm3d:
+
+
bm3d=sigma=3:block=4:bstep=2:group=1:estim=basic
+
- Same as above, but filtering only luma:
+
+
bm3d=sigma=3:block=4:bstep=2:group=1:estim=basic:planes=1
+
- Same as above, but with both estimation modes:
+
+
split[a][b],[a]bm3d=sigma=3:block=4:bstep=2:group=1:estim=basic[a],[b][a]bm3d=sigma=3:block=4:bstep=2:group=16:estim=final:ref=1
+
- Same as above, but prefilter with nlmeans filter instead:
+
+
split[a][b],[a]nlmeans=s=3:r=7:p=3[a],[b][a]bm3d=sigma=3:block=4:bstep=2:group=16:estim=final:ref=1
+
+
+
+
+
+
39.19 boxblur
+
+
Apply a boxblur algorithm to the input video.
+
+
It accepts the following parameters:
+
+
+- luma_radius, lr
+- luma_power, lp
+- chroma_radius, cr
+- chroma_power, cp
+- alpha_radius, ar
+- alpha_power, ap
+
+
+
A description of the accepted options follows.
+
+
+- luma_radius, lr
+- chroma_radius, cr
+- alpha_radius, ar
+Set an expression for the box radius in pixels used for blurring the
+corresponding input plane.
+
+The radius value must be a non-negative number, and must not be
+greater than the value of the expression min(w,h)/2 for the
+luma and alpha planes, and of min(cw,ch)/2 for the chroma
+planes.
+
+Default value for luma_radius is "2". If not specified,
+chroma_radius and alpha_radius default to the
+corresponding value set for luma_radius.
+
+The expressions can contain the following constants:
+
+- w
+- h
+The input width and height in pixels.
+
+- cw
+- ch
+The input chroma image width and height in pixels.
+
+- hsub
+- vsub
+The horizontal and vertical chroma subsample values. For example, for the
+pixel format "yuv422p", hsub is 2 and vsub is 1.
+
+
+- luma_power, lp
+- chroma_power, cp
+- alpha_power, ap
+Specify how many times the boxblur filter is applied to the
+corresponding plane.
+
+Default value for luma_power is 2. If not specified,
+chroma_power and alpha_power default to the
+corresponding value set for luma_power.
+
+A value of 0 will disable the effect.
+
+
+
+
+
39.19.1 Examples
+
+
+- Apply a boxblur filter with the luma, chroma, and alpha radii
+set to 2:
+
+
boxblur=luma_radius=2:luma_power=1
+boxblur=2:1
+
- Set the luma radius to 2, and alpha and chroma radius to 0:
+
+
+
- Set the luma and chroma radii to a fraction of the video dimension:
+
+
boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
+
+
+
+
+
+
39.20 bwdif
+
+
Deinterlace the input video ("bwdif" stands for "Bob Weaver
+Deinterlacing Filter").
+
+
Motion adaptive deinterlacing based on yadif with the use of w3fdif and cubic
+interpolation algorithms.
+It accepts the following parameters:
+
+
+- mode
+The interlacing mode to adopt. It accepts one of the following values:
+
+
+- 0, send_frame
+Output one frame for each frame.
+
- 1, send_field
+Output one frame for each field.
+
+
+The default value is send_field.
+
+- parity
+The picture field parity assumed for the input interlaced video. It accepts one
+of the following values:
+
+
+- 0, tff
+Assume the top field is first.
+
- 1, bff
+Assume the bottom field is first.
+
- -1, auto
+Enable automatic detection of field parity.
+
+
+The default value is auto.
+If the interlacing is unknown or the decoder does not export this information,
+top field first will be assumed.
+
+- deint
+Specify which frames to deinterlace. Accepts one of the following
+values:
+
+
+- 0, all
+Deinterlace all frames.
+
- 1, interlaced
+Only deinterlace frames marked as interlaced.
+
+
+The default value is all.
+
+
+
+
+
39.21 ccrepack
+
+
Repack CEA-708 closed captioning side data
+
+
This filter fixes various issues seen with commerical encoders
+related to upstream malformed CEA-708 payloads, specifically
+incorrect number of tuples (wrong cc_count for the target FPS),
+and incorrect ordering of tuples (i.e. the CEA-608 tuples are not at
+the first entries in the payload).
+
+
+
+
39.22 cas
+
+
Apply Contrast Adaptive Sharpen filter to video stream.
+
+
The filter accepts the following options:
+
+
+- strength
+Set the sharpening strength. Default value is 0.
+
+- planes
+Set planes to filter. Default value is to filter all
+planes except alpha plane.
+
+
+
+
+
39.22.1 Commands
+
This filter supports same commands as options.
+
+
+
+
+
39.23 chromahold
+
Remove all color information for all colors except for certain one.
+
+
The filter accepts the following options:
+
+
+- color
+The color which will not be replaced with neutral chroma.
+
+- similarity
+Similarity percentage with the above color.
+0.01 matches only the exact key color, while 1.0 matches everything.
+
+- blend
+Blend percentage.
+0.0 makes pixels either fully gray, or not gray at all.
+Higher values result in more preserved color.
+
+- yuv
+Signals that the color passed is already in YUV instead of RGB.
+
+Literal colors like "green" or "red" don’t make sense with this enabled anymore.
+This can be used to pass exact YUV values as hexadecimal numbers.
+
+
+
+
+
39.23.1 Commands
+
This filter supports same commands as options.
+The command accepts the same syntax of the corresponding option.
+
+
If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
39.24 chromakey
+
YUV colorspace color/chroma keying.
+
+
The filter accepts the following options:
+
+
+- color
+The color which will be replaced with transparency.
+
+- similarity
+Similarity percentage with the key color.
+
+0.01 matches only the exact key color, while 1.0 matches everything.
+
+- blend
+Blend percentage.
+
+0.0 makes pixels either fully transparent, or not transparent at all.
+
+Higher values result in semi-transparent pixels, with a higher transparency
+the more similar the pixels color is to the key color.
+
+- yuv
+Signals that the color passed is already in YUV instead of RGB.
+
+Literal colors like "green" or "red" don’t make sense with this enabled anymore.
+This can be used to pass exact YUV values as hexadecimal numbers.
+
+
+
+
+
39.24.1 Commands
+
This filter supports same commands as options.
+The command accepts the same syntax of the corresponding option.
+
+
If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
39.24.2 Examples
+
+
+- Make every green pixel in the input image transparent:
+
+
ffmpeg -i input.png -vf chromakey=green out.png
+
- Overlay a greenscreen-video on top of a static black background.
+
+
ffmpeg -f lavfi -i color=c=black:s=1280x720 -i video.mp4 -shortest -filter_complex "[1:v]chromakey=0x70de77:0.1:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.mkv
+
+
+
+
+
+
39.25 chromakey_cuda
+
CUDA accelerated YUV colorspace color/chroma keying.
+
+
This filter works like normal chromakey filter but operates on CUDA frames.
+for more details and parameters see chromakey.
+
+
+
+
39.25.1 Examples
+
+
+- Make all the green pixels in the input video transparent and use it as an overlay for another video:
+
+
+
./ffmpeg \
+ -hwaccel cuda -hwaccel_output_format cuda -i input_green.mp4 \
+ -hwaccel cuda -hwaccel_output_format cuda -i base_video.mp4 \
+ -init_hw_device cuda \
+ -filter_complex \
+ " \
+ [0:v]chromakey_cuda=0x25302D:0.1:0.12:1[overlay_video]; \
+ [1:v]scale_cuda=format=yuv420p[base]; \
+ [base][overlay_video]overlay_cuda" \
+ -an -sn -c:v h264_nvenc -cq 20 output.mp4
+
- Process two software sources, explicitly uploading the frames:
+
+
+
./ffmpeg -init_hw_device cuda=cuda -filter_hw_device cuda \
+ -f lavfi -i color=size=800x600:color=white,format=yuv420p \
+ -f lavfi -i yuvtestsrc=size=200x200,format=yuv420p \
+ -filter_complex \
+ " \
+ [0]hwupload[under]; \
+ [1]hwupload,chromakey_cuda=green:0.1:0.12[over]; \
+ [under][over]overlay_cuda" \
+ -c:v hevc_nvenc -cq 18 -preset slow output.mp4
+
+
+
+
+
+
39.26 chromanr
+
Reduce chrominance noise.
+
+
The filter accepts the following options:
+
+
+- thres
+Set threshold for averaging chrominance values.
+Sum of absolute difference of Y, U and V pixel components of current
+pixel and neighbour pixels lower than this threshold will be used in
+averaging. Luma component is left unchanged and is copied to output.
+Default value is 30. Allowed range is from 1 to 200.
+
+- sizew
+Set horizontal radius of rectangle used for averaging.
+Allowed range is from 1 to 100. Default value is 5.
+
+- sizeh
+Set vertical radius of rectangle used for averaging.
+Allowed range is from 1 to 100. Default value is 5.
+
+- stepw
+Set horizontal step when averaging. Default value is 1.
+Allowed range is from 1 to 50.
+Mostly useful to speed-up filtering.
+
+- steph
+Set vertical step when averaging. Default value is 1.
+Allowed range is from 1 to 50.
+Mostly useful to speed-up filtering.
+
+- threy
+Set Y threshold for averaging chrominance values.
+Set finer control for max allowed difference between Y components
+of current pixel and neigbour pixels.
+Default value is 200. Allowed range is from 1 to 200.
+
+- threu
+Set U threshold for averaging chrominance values.
+Set finer control for max allowed difference between U components
+of current pixel and neigbour pixels.
+Default value is 200. Allowed range is from 1 to 200.
+
+- threv
+Set V threshold for averaging chrominance values.
+Set finer control for max allowed difference between V components
+of current pixel and neigbour pixels.
+Default value is 200. Allowed range is from 1 to 200.
+
+- distance
+Set distance type used in calculations.
+
+
+- ‘manhattan’
+Absolute difference.
+
- ‘euclidean’
+Difference squared.
+
+
+Default distance type is manhattan.
+
+
+
+
+
39.26.1 Commands
+
This filter supports same commands as options.
+The command accepts the same syntax of the corresponding option.
+
+
+
+
+
39.27 chromashift
+
Shift chroma pixels horizontally and/or vertically.
+
+
The filter accepts the following options:
+
+- cbh
+Set amount to shift chroma-blue horizontally.
+
- cbv
+Set amount to shift chroma-blue vertically.
+
- crh
+Set amount to shift chroma-red horizontally.
+
- crv
+Set amount to shift chroma-red vertically.
+
- edge
+Set edge mode, can be smear, default, or warp.
+
+
+
+
+
39.27.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.28 ciescope
+
+
Display CIE color diagram with pixels overlaid onto it.
+
+
The filter accepts the following options:
+
+
+- system
+Set color system.
+
+
+- ‘ntsc, 470m’
+- ‘ebu, 470bg’
+- ‘smpte’
+- ‘240m’
+- ‘apple’
+- ‘widergb’
+- ‘cie1931’
+- ‘rec709, hdtv’
+- ‘uhdtv, rec2020’
+- ‘dcip3’
+
+
+- cie
+Set CIE system.
+
+
+- ‘xyy’
+- ‘ucs’
+- ‘luv’
+
+
+- gamuts
+Set what gamuts to draw.
+
+See system option for available values.
+
+- size, s
+Set ciescope size, by default set to 512.
+
+- intensity, i
+Set intensity used to map input pixel values to CIE diagram.
+
+- contrast
+Set contrast used to draw tongue colors that are out of active color system gamut.
+
+- corrgamma
+Correct gamma displayed on scope, by default enabled.
+
+- showwhite
+Show white point on CIE diagram, by default disabled.
+
+- gamma
+Set input gamma. Used only with XYZ input color space.
+
+- fill
+Fill with CIE colors. By default is enabled.
+
+
+
+
+
39.29 codecview
+
+
Visualize information exported by some codecs.
+
+
Some codecs can export information through frames using side-data or other
+means. For example, some MPEG based codecs export motion vectors through the
+export_mvs flag in the codec flags2 option.
+
+
The filter accepts the following option:
+
+
+- block
+Display block partition structure using the luma plane.
+
+- mv
+Set motion vectors to visualize.
+
+Available flags for mv are:
+
+
+- ‘pf’
+forward predicted MVs of P-frames
+
- ‘bf’
+forward predicted MVs of B-frames
+
- ‘bb’
+backward predicted MVs of B-frames
+
+
+- qp
+Display quantization parameters using the chroma planes.
+
+- mv_type, mvt
+Set motion vectors type to visualize. Includes MVs from all frames unless specified by frame_type option.
+
+Available flags for mv_type are:
+
+
+- ‘fp’
+forward predicted MVs
+
- ‘bp’
+backward predicted MVs
+
+
+- frame_type, ft
+Set frame type to visualize motion vectors of.
+
+Available flags for frame_type are:
+
+
+- ‘if’
+intra-coded frames (I-frames)
+
- ‘pf’
+predicted frames (P-frames)
+
- ‘bf’
+bi-directionally predicted frames (B-frames)
+
+
+
+
+
+
39.29.1 Examples
+
+
+- Visualize forward predicted MVs of all frames using
ffplay:
+
+
ffplay -flags2 +export_mvs input.mp4 -vf codecview=mv_type=fp
+
- Visualize multi-directionals MVs of P and B-Frames using
ffplay:
+
+
ffplay -flags2 +export_mvs input.mp4 -vf codecview=mv=pf+bf+bb
+
+
+
+
+
+
39.30 colorbalance
+
Modify intensity of primary colors (red, green and blue) of input frames.
+
+
The filter allows an input frame to be adjusted in the shadows, midtones or highlights
+regions for the red-cyan, green-magenta or blue-yellow balance.
+
+
A positive adjustment value shifts the balance towards the primary color, a negative
+value towards the complementary color.
+
+
The filter accepts the following options:
+
+
+- rs
+- gs
+- bs
+Adjust red, green and blue shadows (darkest pixels).
+
+- rm
+- gm
+- bm
+Adjust red, green and blue midtones (medium pixels).
+
+- rh
+- gh
+- bh
+Adjust red, green and blue highlights (brightest pixels).
+
+Allowed ranges for options are [-1.0, 1.0]. Defaults are 0.
+
+- pl
+Preserve lightness when changing color balance. Default is disabled.
+
+
+
+
+
39.30.1 Examples
+
+
+- Add red color cast to shadows:
+
+
+
+
+
+
39.30.2 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.31 colorcontrast
+
+
Adjust color contrast between RGB components.
+
+
The filter accepts the following options:
+
+
+- rc
+Set the red-cyan contrast. Defaults is 0.0. Allowed range is from -1.0 to 1.0.
+
+- gm
+Set the green-magenta contrast. Defaults is 0.0. Allowed range is from -1.0 to 1.0.
+
+- by
+Set the blue-yellow contrast. Defaults is 0.0. Allowed range is from -1.0 to 1.0.
+
+- rcw
+- gmw
+- byw
+Set the weight of each rc, gm, by option value. Default value is 0.0.
+Allowed range is from 0.0 to 1.0. If all weights are 0.0 filtering is disabled.
+
+- pl
+Set the amount of preserving lightness. Default value is 0.0. Allowed range is from 0.0 to 1.0.
+
+
+
+
+
39.31.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.32 colorcorrect
+
+
Adjust color white balance selectively for blacks and whites.
+This filter operates in YUV colorspace.
+
+
The filter accepts the following options:
+
+
+- rl
+Set the red shadow spot. Allowed range is from -1.0 to 1.0.
+Default value is 0.
+
+- bl
+Set the blue shadow spot. Allowed range is from -1.0 to 1.0.
+Default value is 0.
+
+- rh
+Set the red highlight spot. Allowed range is from -1.0 to 1.0.
+Default value is 0.
+
+- bh
+Set the blue highlight spot. Allowed range is from -1.0 to 1.0.
+Default value is 0.
+
+- saturation
+Set the amount of saturation. Allowed range is from -3.0 to 3.0.
+Default value is 1.
+
+- analyze
+If set to anything other than manual it will analyze every frame and use derived
+parameters for filtering output frame.
+
+Possible values are:
+
+- ‘manual’
+- ‘average’
+- ‘minmax’
+- ‘median’
+
+Default value is manual.
+
+
+
+
+
39.32.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.33 colorchannelmixer
+
+
Adjust video input frames by re-mixing color channels.
+
+
This filter modifies a color channel by adding the values associated to
+the other channels of the same pixels. For example if the value to
+modify is red, the output value will be:
+
+
red=red*rr + blue*rb + green*rg + alpha*ra
+
+
+
The filter accepts the following options:
+
+
+- rr
+- rg
+- rb
+- ra
+Adjust contribution of input red, green, blue and alpha channels for output red channel.
+Default is 1 for rr, and 0 for rg, rb and ra.
+
+- gr
+- gg
+- gb
+- ga
+Adjust contribution of input red, green, blue and alpha channels for output green channel.
+Default is 1 for gg, and 0 for gr, gb and ga.
+
+- br
+- bg
+- bb
+- ba
+Adjust contribution of input red, green, blue and alpha channels for output blue channel.
+Default is 1 for bb, and 0 for br, bg and ba.
+
+- ar
+- ag
+- ab
+- aa
+Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
+Default is 1 for aa, and 0 for ar, ag and ab.
+
+Allowed ranges for options are [-2.0, 2.0].
+
+- pc
+Set preserve color mode. The accepted values are:
+
+- ‘none’
+Disable color preserving, this is default.
+
- ‘lum’
+Preserve luminance.
+
- ‘max’
+Preserve max value of RGB triplet.
+
- ‘avg’
+Preserve average value of RGB triplet.
+
- ‘sum’
+Preserve sum value of RGB triplet.
+
- ‘nrm’
+Preserve normalized value of RGB triplet.
+
- ‘pwr’
+Preserve power value of RGB triplet.
+
+
+- pa
+Set the preserve color amount when changing colors. Allowed range is from [0.0, 1.0].
+Default is 0.0, thus disabled.
+
+
+
+
+
39.33.1 Examples
+
+
+- Convert source to grayscale:
+
+
colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
+
- Simulate sepia tones:
+
+
colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
+
+
+
+
+
39.33.2 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.34 colorize
+
Overlay a solid color on the video stream.
+
+
The filter accepts the following options:
+
+
+- hue
+Set the color hue. Allowed range is from 0 to 360.
+Default value is 0.
+
+- saturation
+Set the color saturation. Allowed range is from 0 to 1.
+Default value is 0.5.
+
+- lightness
+Set the color lightness. Allowed range is from 0 to 1.
+Default value is 0.5.
+
+- mix
+Set the mix of source lightness. By default is set to 1.0.
+Allowed range is from 0.0 to 1.0.
+
+
+
+
+
39.34.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.35 colorkey
+
RGB colorspace color keying.
+This filter operates on 8-bit RGB format frames by setting the alpha component of each pixel
+which falls within the similarity radius of the key color to 0. The alpha value for pixels outside
+the similarity radius depends on the value of the blend option.
+
+
The filter accepts the following options:
+
+
+- color
+Set the color for which alpha will be set to 0 (full transparency).
+See (ffmpeg-utils)"Color" section in the ffmpeg-utils manual.
+Default is black.
+
+- similarity
+Set the radius from the key color within which other colors also have full transparency.
+The computed distance is related to the unit fractional distance in 3D space between the RGB values
+of the key color and the pixel’s color. Range is 0.01 to 1.0. 0.01 matches within a very small radius
+around the exact key color, while 1.0 matches everything.
+Default is 0.01.
+
+- blend
+Set how the alpha value for pixels that fall outside the similarity radius is computed.
+0.0 makes pixels either fully transparent or fully opaque.
+Higher values result in semi-transparent pixels, with greater transparency
+the more similar the pixel color is to the key color.
+Range is 0.0 to 1.0. Default is 0.0.
+
+
+
+
+
39.35.1 Examples
+
+
+- Make every green pixel in the input image transparent:
+
+
ffmpeg -i input.png -vf colorkey=green out.png
+
- Overlay a greenscreen-video on top of a static background image.
+
+
ffmpeg -i background.png -i video.mp4 -filter_complex "[1:v]colorkey=0x3BBD1E:0.3:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.flv
+
+
+
+
+
39.35.2 Commands
+
This filter supports same commands as options.
+The command accepts the same syntax of the corresponding option.
+
+
If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
39.36 colorhold
+
Remove all color information for all RGB colors except for certain one.
+
+
The filter accepts the following options:
+
+
+- color
+The color which will not be replaced with neutral gray.
+
+- similarity
+Similarity percentage with the above color.
+0.01 matches only the exact key color, while 1.0 matches everything.
+
+- blend
+Blend percentage. 0.0 makes pixels fully gray.
+Higher values result in more preserved color.
+
+
+
+
+
39.36.1 Commands
+
This filter supports same commands as options.
+The command accepts the same syntax of the corresponding option.
+
+
If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
39.37 colorlevels
+
+
Adjust video input frames using levels.
+
+
The filter accepts the following options:
+
+
+- rimin
+- gimin
+- bimin
+- aimin
+Adjust red, green, blue and alpha input black point.
+Allowed ranges for options are [-1.0, 1.0]. Defaults are 0.
+
+- rimax
+- gimax
+- bimax
+- aimax
+Adjust red, green, blue and alpha input white point.
+Allowed ranges for options are [-1.0, 1.0]. Defaults are 1.
+
+Input levels are used to lighten highlights (bright tones), darken shadows
+(dark tones), change the balance of bright and dark tones.
+
+- romin
+- gomin
+- bomin
+- aomin
+Adjust red, green, blue and alpha output black point.
+Allowed ranges for options are [0, 1.0]. Defaults are 0.
+
+- romax
+- gomax
+- bomax
+- aomax
+Adjust red, green, blue and alpha output white point.
+Allowed ranges for options are [0, 1.0]. Defaults are 1.
+
+Output levels allows manual selection of a constrained output level range.
+
+- preserve
+Set preserve color mode. The accepted values are:
+
+- ‘none’
+Disable color preserving, this is default.
+
- ‘lum’
+Preserve luminance.
+
- ‘max’
+Preserve max value of RGB triplet.
+
- ‘avg’
+Preserve average value of RGB triplet.
+
- ‘sum’
+Preserve sum value of RGB triplet.
+
- ‘nrm’
+Preserve normalized value of RGB triplet.
+
- ‘pwr’
+Preserve power value of RGB triplet.
+
+
+
+
+
+
39.37.1 Examples
+
+
+- Make video output darker:
+
+
colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
+
- Increase contrast:
+
+
colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
+
- Make video output lighter:
+
+
colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
+
- Increase brightness:
+
+
colorlevels=romin=0.5:gomin=0.5:bomin=0.5
+
+
+
+
+
39.37.2 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.38 colormap
+
Apply custom color maps to video stream.
+
+
This filter needs three input video streams.
+First stream is video stream that is going to be filtered out.
+Second and third video stream specify color patches for source
+color to target color mapping.
+
+
The filter accepts the following options:
+
+
+- patch_size
+Set the source and target video stream patch size in pixels.
+
+- nb_patches
+Set the max number of used patches from source and target video stream.
+Default value is number of patches available in additional video streams.
+Max allowed number of patches is 64.
+
+- type
+Set the adjustments used for target colors. Can be relative or absolute.
+Defaults is absolute.
+
+- kernel
+Set the kernel used to measure color differences between mapped colors.
+
+The accepted values are:
+
+- ‘euclidean’
+- ‘weuclidean’
+
+
+Default is euclidean.
+
+
+
+
+
39.39 colormatrix
+
+
Convert color matrix.
+
+
The filter accepts the following options:
+
+
+- src
+- dst
+Specify the source and destination color matrix. Both values must be
+specified.
+
+The accepted values are:
+
+- ‘bt709’
+BT.709
+
+- ‘fcc’
+FCC
+
+- ‘bt601’
+BT.601
+
+- ‘bt470’
+BT.470
+
+- ‘bt470bg’
+BT.470BG
+
+- ‘smpte170m’
+SMPTE-170M
+
+- ‘smpte240m’
+SMPTE-240M
+
+- ‘bt2020’
+BT.2020
+
+
+
+
For example to convert from BT.601 to SMPTE-240M, use the command:
+
+
colormatrix=bt601:smpte240m
+
+
+
+
+
39.40 colorspace
+
+
Convert colorspace, transfer characteristics or color primaries.
+Input video needs to have an even size.
+
+
The filter accepts the following options:
+
+
+- all
+Specify all color properties at once.
+
+The accepted values are:
+
+- ‘bt470m’
+BT.470M
+
+- ‘bt470bg’
+BT.470BG
+
+- ‘bt601-6-525’
+BT.601-6 525
+
+- ‘bt601-6-625’
+BT.601-6 625
+
+- ‘bt709’
+BT.709
+
+- ‘smpte170m’
+SMPTE-170M
+
+- ‘smpte240m’
+SMPTE-240M
+
+- ‘bt2020’
+BT.2020
+
+
+
+- space
+Specify output colorspace.
+
+The accepted values are:
+
+- ‘bt709’
+BT.709
+
+- ‘fcc’
+FCC
+
+- ‘bt470bg’
+BT.470BG or BT.601-6 625
+
+- ‘smpte170m’
+SMPTE-170M or BT.601-6 525
+
+- ‘smpte240m’
+SMPTE-240M
+
+- ‘ycgco’
+YCgCo
+
+- ‘bt2020ncl’
+BT.2020 with non-constant luminance
+
+
+
+- trc
+Specify output transfer characteristics.
+
+The accepted values are:
+
+- ‘bt709’
+BT.709
+
+- ‘bt470m’
+BT.470M
+
+- ‘bt470bg’
+BT.470BG
+
+- ‘gamma22’
+Constant gamma of 2.2
+
+- ‘gamma28’
+Constant gamma of 2.8
+
+- ‘smpte170m’
+SMPTE-170M, BT.601-6 625 or BT.601-6 525
+
+- ‘smpte240m’
+SMPTE-240M
+
+- ‘srgb’
+SRGB
+
+- ‘iec61966-2-1’
+iec61966-2-1
+
+- ‘iec61966-2-4’
+iec61966-2-4
+
+- ‘xvycc’
+xvycc
+
+- ‘bt2020-10’
+BT.2020 for 10-bits content
+
+- ‘bt2020-12’
+BT.2020 for 12-bits content
+
+
+
+- primaries
+Specify output color primaries.
+
+The accepted values are:
+
+- ‘bt709’
+BT.709
+
+- ‘bt470m’
+BT.470M
+
+- ‘bt470bg’
+BT.470BG or BT.601-6 625
+
+- ‘smpte170m’
+SMPTE-170M or BT.601-6 525
+
+- ‘smpte240m’
+SMPTE-240M
+
+- ‘film’
+film
+
+- ‘smpte431’
+SMPTE-431
+
+- ‘smpte432’
+SMPTE-432
+
+- ‘bt2020’
+BT.2020
+
+- ‘jedec-p22’
+JEDEC P22 phosphors
+
+
+
+- range
+Specify output color range.
+
+The accepted values are:
+
+- ‘tv’
+TV (restricted) range
+
+- ‘mpeg’
+MPEG (restricted) range
+
+- ‘pc’
+PC (full) range
+
+- ‘jpeg’
+JPEG (full) range
+
+
+
+- format
+Specify output color format.
+
+The accepted values are:
+
+- ‘yuv420p’
+YUV 4:2:0 planar 8-bits
+
+- ‘yuv420p10’
+YUV 4:2:0 planar 10-bits
+
+- ‘yuv420p12’
+YUV 4:2:0 planar 12-bits
+
+- ‘yuv422p’
+YUV 4:2:2 planar 8-bits
+
+- ‘yuv422p10’
+YUV 4:2:2 planar 10-bits
+
+- ‘yuv422p12’
+YUV 4:2:2 planar 12-bits
+
+- ‘yuv444p’
+YUV 4:4:4 planar 8-bits
+
+- ‘yuv444p10’
+YUV 4:4:4 planar 10-bits
+
+- ‘yuv444p12’
+YUV 4:4:4 planar 12-bits
+
+
+
+- fast
+Do a fast conversion, which skips gamma/primary correction. This will take
+significantly less CPU, but will be mathematically incorrect. To get output
+compatible with that produced by the colormatrix filter, use fast=1.
+
+- dither
+Specify dithering mode.
+
+The accepted values are:
+
+- ‘none’
+No dithering
+
+- ‘fsb’
+Floyd-Steinberg dithering
+
+
+- wpadapt
+Whitepoint adaptation mode.
+
+The accepted values are:
+
+- ‘bradford’
+Bradford whitepoint adaptation
+
+- ‘vonkries’
+von Kries whitepoint adaptation
+
+- ‘identity’
+identity whitepoint adaptation (i.e. no whitepoint adaptation)
+
+
+- iall
+Override all input properties at once. Same accepted values as all.
+
+- ispace
+Override input colorspace. Same accepted values as space.
+
+- iprimaries
+Override input color primaries. Same accepted values as primaries.
+
+- itrc
+Override input transfer characteristics. Same accepted values as trc.
+
+- irange
+Override input color range. Same accepted values as range.
+
+
+
+
The filter converts the transfer characteristics, color space and color
+primaries to the specified user values. The output value, if not specified,
+is set to a default value based on the "all" property. If that property is
+also not specified, the filter will log an error. The output color range and
+format default to the same value as the input color range and format. The
+input transfer characteristics, color space, color primaries and color range
+should be set on the input data. If any of these are missing, the filter will
+log an error and no conversion will take place.
+
+
For example to convert the input to SMPTE-240M, use the command:
+
+
+
+
+
39.41 colorspace_cuda
+
+
CUDA accelerated implementation of the colorspace filter.
+
+
It is by no means feature complete compared to the software colorspace filter,
+and at the current time only supports color range conversion between jpeg/full
+and mpeg/limited range.
+
+
The filter accepts the following options:
+
+
+- range
+Specify output color range.
+
+The accepted values are:
+
+- ‘tv’
+TV (restricted) range
+
+- ‘mpeg’
+MPEG (restricted) range
+
+- ‘pc’
+PC (full) range
+
+- ‘jpeg’
+JPEG (full) range
+
+
+
+
+
+
+
+
39.42 colortemperature
+
Adjust color temperature in video to simulate variations in ambient color temperature.
+
+
The filter accepts the following options:
+
+
+- temperature
+Set the temperature in Kelvin. Allowed range is from 1000 to 40000.
+Default value is 6500 K.
+
+- mix
+Set mixing with filtered output. Allowed range is from 0 to 1.
+Default value is 1.
+
+- pl
+Set the amount of preserving lightness. Allowed range is from 0 to 1.
+Default value is 0.
+
+
+
+
+
39.42.1 Commands
+
This filter supports same commands as options.
+
+
+
+
+
39.43 convolution
+
+
Apply convolution of 3x3, 5x5, 7x7 or horizontal/vertical up to 49 elements.
+
+
The filter accepts the following options:
+
+
+- 0m
+- 1m
+- 2m
+- 3m
+Set matrix for each plane.
+Matrix is sequence of 9, 25 or 49 signed integers in square mode,
+and from 1 to 49 odd number of signed integers in row mode.
+
+- 0rdiv
+- 1rdiv
+- 2rdiv
+- 3rdiv
+Set multiplier for calculated value for each plane.
+If unset or 0, it will be sum of all matrix elements.
+
+- 0bias
+- 1bias
+- 2bias
+- 3bias
+Set bias for each plane. This value is added to the result of the multiplication.
+Useful for making the overall image brighter or darker. Default is 0.0.
+
+- 0mode
+- 1mode
+- 2mode
+- 3mode
+Set matrix mode for each plane. Can be square, row or column.
+Default is square.
+
+
+
+
+
39.43.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
39.43.2 Examples
+
+
+- Apply sharpen:
+
+
convolution="0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0"
+
- Apply blur:
+
+
convolution="1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1/9:1/9:1/9:1/9"
+
- Apply edge enhance:
+
+
convolution="0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:5:1:1:1:0:128:128:128"
+
- Apply edge detect:
+
+
convolution="0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:5:5:5:1:0:128:128:128"
+
- Apply laplacian edge detector which includes diagonals:
+
+
convolution="1 1 1 1 -8 1 1 1 1:1 1 1 1 -8 1 1 1 1:1 1 1 1 -8 1 1 1 1:1 1 1 1 -8 1 1 1 1:5:5:5:1:0:128:128:0"
+
- Apply emboss:
+
+
convolution="-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2"
+
+
+
+
+
+
39.44 convolve
+
+
Apply 2D convolution of video stream in frequency domain using second stream
+as impulse.
+
+
The filter accepts the following options:
+
+
+- planes
+Set which planes to process.
+
+- impulse
+Set which impulse video frames will be processed, can be first
+or all. Default is all.
+
+
+
The convolve filter also supports the framesync options.
+
+
+
+
39.45 copy
+
+
Copy the input video source unchanged to the output. This is mainly useful for
+testing purposes.
+
+
+
+
39.46 coreimage
+
Video filtering on GPU using Apple’s CoreImage API on OSX.
+
+
Hardware acceleration is based on an OpenGL context. Usually, this means it is
+processed by video hardware. However, software-based OpenGL implementations
+exist which means there is no guarantee for hardware processing. It depends on
+the respective OSX.
+
+
There are many filters and image generators provided by Apple that come with a
+large variety of options. The filter has to be referenced by its name along
+with its options.
+
+
The coreimage filter accepts the following options:
+
+- list_filters
+List all available filters and generators along with all their respective
+options as well as possible minimum and maximum values along with the default
+values.
+
+
+- filter
+Specify all filters by their respective name and options.
+Use list_filters to determine all valid filter names and options.
+Numerical options are specified by a float value and are automatically clamped
+to their respective value range. Vector and color options have to be specified
+by a list of space separated float values. Character escaping has to be done.
+A special option name default is available to use default options for a
+filter.
+
+It is required to specify either default or at least one of the filter options.
+All omitted options are used with their default values.
+The syntax of the filter string is as follows:
+
+
filter=<NAME>@<OPTION>=<VALUE>[@<OPTION>=<VALUE>][@...][#<NAME>@<OPTION>=<VALUE>[@<OPTION>=<VALUE>][@...]][#...]
+
- output_rect
+Specify a rectangle where the output of the filter chain is copied into the
+input image. It is given by a list of space separated float values:
+
+
output_rect=x\ y\ width\ height
+
If not given, the output rectangle equals the dimensions of the input image.
+The output rectangle is automatically cropped at the borders of the input
+image. Negative values are valid for each component.
+
+
output_rect=25\ 25\ 100\ 100
+
+
+
Several filters can be chained for successive processing without GPU-HOST
+transfers allowing for fast processing of complex filter chains.
+Currently, only filters with zero (generators) or exactly one (filters) input
+image and one output image are supported. Also, transition filters are not yet
+usable as intended.
+
+
Some filters generate output images with additional padding depending on the
+respective filter kernel. The padding is automatically removed to ensure the
+filter output has the same size as the input image.
+
+
For image generators, the size of the output image is determined by the
+previous output image of the filter chain or the input image of the whole
+filterchain, respectively. The generators do not use the pixel information of
+this image to generate their output. However, the generated output is
+blended onto this image, resulting in partial or complete coverage of the
+output image.
+
+
The coreimagesrc video source can be used for generating input images
+which are directly fed into the filter chain. By using it, providing input
+images by another video source or an input video is not required.
+
+
+
+
39.46.1 Examples
+
+
+- List all filters available:
+
+
coreimage=list_filters=true
+
- Use the CIBoxBlur filter with default options to blur an image:
+
+
coreimage=filter=CIBoxBlur@default
+
- Use a filter chain with CISepiaTone at default values and CIVignetteEffect with
+its center at 100x100 and a radius of 50 pixels:
+
+
coreimage=filter=CIBoxBlur@default#CIVignetteEffect@inputCenter=100\ 100@inputRadius=50
+
- Use nullsrc and CIQRCodeGenerator to create a QR code for the FFmpeg homepage,
+given as complete and escaped command-line for Apple’s standard bash shell:
+
+
ffmpeg -f lavfi -i nullsrc=s=100x100,coreimage=filter=CIQRCodeGenerator@inputMessage=https\\\\\://FFmpeg.org/@inputCorrectionLevel=H -frames:v 1 QRCode.png
+
+
+
+
+
+
39.47 corr
+
+
Obtain the correlation between two input videos.
+
+
This filter takes two input videos.
+
+
Both input videos must have the same resolution and pixel format for
+this filter to work correctly. Also it assumes that both inputs
+have the same number of frames, which are compared one by one.
+
+
The obtained per component, average, min and max correlation is printed through
+the logging system.
+
+
The filter stores the calculated correlation of each frame in frame metadata.
+
+
This filter also supports the framesync options.
+
+
In the below example the input file main.mpg being processed is compared
+with the reference file ref.mpg.
+
+
+
ffmpeg -i main.mpg -i ref.mpg -lavfi corr -f null -
+
+
+
+
+
39.48 cover_rect
+
+
Cover a rectangular object
+
+
It accepts the following options:
+
+
+- cover
+Filepath of the optional cover image, needs to be in yuv420.
+
+- mode
+Set covering mode.
+
+It accepts the following values:
+
+- ‘cover’
+cover it by the supplied image
+
- ‘blur’
+cover it by interpolating the surrounding pixels
+
+
+Default value is blur.
+
+
+
+
+
39.48.1 Examples
+
+
+- Cover a rectangular object by the supplied image of a given video using
ffmpeg:
+
+
ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
+
+
+
+
+
+
39.49 crop
+
+
Crop the input video to given dimensions.
+
+
It accepts the following parameters:
+
+
+- w, out_w
+The width of the output video. It defaults to iw.
+This expression is evaluated only once during the filter
+configuration, or when the ‘w’ or ‘out_w’ command is sent.
+
+- h, out_h
+The height of the output video. It defaults to ih.
+This expression is evaluated only once during the filter
+configuration, or when the ‘h’ or ‘out_h’ command is sent.
+
+- x
+The horizontal position, in the input video, of the left edge of the output
+video. It defaults to (in_w-out_w)/2.
+This expression is evaluated per-frame.
+
+- y
+The vertical position, in the input video, of the top edge of the output video.
+It defaults to (in_h-out_h)/2.
+This expression is evaluated per-frame.
+
+- keep_aspect
+If set to 1 will force the output display aspect ratio
+to be the same of the input, by changing the output sample aspect
+ratio. It defaults to 0.
+
+- exact
+Enable exact cropping. If enabled, subsampled videos will be cropped at exact
+width/height/x/y as specified and will not be rounded to nearest smaller value.
+It defaults to 0.
+
+
+
The out_w, out_h, x, y parameters are
+expressions containing the following constants:
+
+
+- x
+- y
+The computed values for x and y. They are evaluated for
+each new frame.
+
+- in_w
+- in_h
+The input width and height.
+
+- iw
+- ih
+These are the same as in_w and in_h.
+
+- out_w
+- out_h
+The output (cropped) width and height.
+
+- ow
+- oh
+These are the same as out_w and out_h.
+
+- a
+same as iw / ih
+
+- sar
+input sample aspect ratio
+
+- dar
+input display aspect ratio, it is the same as (iw / ih) * sar
+
+- hsub
+- vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" hsub is 2 and vsub is 1.
+
+- n
+The number of the input frame, starting from 0.
+
+- pos
+the position in the file of the input frame, NAN if unknown; deprecated,
+do not use
+
+- t
+The timestamp expressed in seconds. It’s NAN if the input timestamp is unknown.
+
+
+
+
The expression for out_w may depend on the value of out_h,
+and the expression for out_h may depend on out_w, but they
+cannot depend on x and y, as x and y are
+evaluated after out_w and out_h.
+
+
The x and y parameters specify the expressions for the
+position of the top-left corner of the output (non-cropped) area. They
+are evaluated for each frame. If the evaluated value is not valid, it
+is approximated to the nearest valid value.
+
+
The expression for x may depend on y, and the expression
+for y may depend on x.
+
+
+
+
39.49.1 Examples
+
+
+
+
+
+
39.49.2 Commands
+
+
This filter supports the following commands:
+
+- w, out_w
+- h, out_h
+- x
+- y
+Set width/height of the output video and the horizontal/vertical position
+in the input video.
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
+
39.50 cropdetect
+
+
Auto-detect the crop size.
+
+
It calculates the necessary cropping parameters and prints the
+recommended parameters via the logging system. The detected dimensions
+correspond to the non-black or video area of the input video according to mode.
+
+
It accepts the following parameters:
+
+
+- mode
+Depending on mode crop detection is based on either the mere black value of surrounding pixels or a combination of motion vectors and edge pixels.
+
+
+- ‘black’
+Detect black pixels surrounding the playing video. For fine control use option limit.
+
+- ‘mvedges’
+Detect the playing video by the motion vectors inside the video and scanning for edge pixels typically forming the border of a playing video.
+
+
+- limit
+Set higher black value threshold, which can be optionally specified
+from nothing (0) to everything (255 for 8-bit based formats). An intensity
+value greater to the set value is considered non-black. It defaults to 24.
+You can also specify a value between 0.0 and 1.0 which will be scaled depending
+on the bitdepth of the pixel format.
+
+- round
+The value which the width/height should be divisible by. It defaults to
+16. The offset is automatically adjusted to center the video. Use 2 to
+get only even dimensions (needed for 4:2:2 video). 16 is best when
+encoding to most video codecs.
+
+- skip
+Set the number of initial frames for which evaluation is skipped.
+Default is 2. Range is 0 to INT_MAX.
+
+- reset_count, reset
+Set the counter that determines after how many frames cropdetect will
+reset the previously detected largest video area and start over to
+detect the current optimal crop area. Default value is 0.
+
+This can be useful when channel logos distort the video area. 0
+indicates ’never reset’, and returns the largest area encountered during
+playback.
+
+- mv_threshold
+Set motion in pixel units as threshold for motion detection. It defaults to 8.
+
+- low
+- high
+Set low and high threshold values used by the Canny thresholding
+algorithm.
+
+The high threshold selects the "strong" edge pixels, which are then
+connected through 8-connectivity with the "weak" edge pixels selected
+by the low threshold.
+
+low and high threshold values must be chosen in the range
+[0,1], and low should be lesser or equal to high.
+
+Default value for low is 5/255, and default value for high
+is 15/255.
+
+
+
+
+
39.50.1 Examples
+
+
+- Find video area surrounded by black borders:
+
+
ffmpeg -i file.mp4 -vf cropdetect,metadata=mode=print -f null -
+
- Find an embedded video area, generate motion vectors beforehand:
+
+
ffmpeg -i file.mp4 -vf mestimate,cropdetect=mode=mvedges,metadata=mode=print -f null -
+
- Find an embedded video area, use motion vectors from decoder:
+
+
ffmpeg -flags2 +export_mvs -i file.mp4 -vf cropdetect=mode=mvedges,metadata=mode=print -f null -
+
+
+
+
+
39.50.2 Commands
+
+
This filter supports the following commands:
+
+
+- limit
+The command accepts the same syntax of the corresponding option.
+If the specified expression is not valid, it is kept at its current value.
+
+
+
+
+
+
39.51 cue
+
+
Delay video filtering until a given wallclock timestamp. The filter first
+passes on preroll amount of frames, then it buffers at most
+buffer amount of frames and waits for the cue. After reaching the cue
+it forwards the buffered frames and also any subsequent frames coming in its
+input.
+
+
The filter can be used synchronize the output of multiple ffmpeg processes for
+realtime output devices like decklink. By putting the delay in the filtering
+chain and pre-buffering frames the process can pass on data to output almost
+immediately after the target wallclock timestamp is reached.
+
+
Perfect frame accuracy cannot be guaranteed, but the result is good enough for
+some use cases.
+
+
+- cue
+The cue timestamp expressed in a UNIX timestamp in microseconds. Default is 0.
+
+- preroll
+The duration of content to pass on as preroll expressed in seconds. Default is 0.
+
+- buffer
+The maximum duration of content to buffer before waiting for the cue expressed
+in seconds. Default is 0.
+
+
+
+
+
+
39.52 curves
+
+
Apply color adjustments using curves.
+
+
This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
+component (red, green and blue) has its values defined by N key points
+tied from each other using a smooth curve. The x-axis represents the pixel
+values from the input frame, and the y-axis the new pixel values to be set for
+the output frame.
+
+
By default, a component curve is defined by the two points (0;0) and
+(1;1). This creates a straight line where each original pixel value is
+"adjusted" to its own value, which means no change to the image.
+
+
The filter allows you to redefine these two points and add some more. A new
+curve will be define to pass smoothly through all these new coordinates. The
+new defined points needs to be strictly increasing over the x-axis, and their
+x and y values must be in the [0;1] interval. The curve is
+formed by using a natural or monotonic cubic spline interpolation, depending
+on the interp option (default: natural). The natural
+spline produces a smoother curve in general while the monotonic (pchip)
+spline guarantees the transitions between the specified points to be
+monotonic. If the computed curves happened to go outside the vector spaces,
+the values will be clipped accordingly.
+
+
The filter accepts the following options:
+
+
+- preset
+Select one of the available color presets. This option can be used in addition
+to the r, g, b parameters; in this case, the later
+options takes priority on the preset values.
+Available presets are:
+
+- ‘none’
+- ‘color_negative’
+- ‘cross_process’
+- ‘darker’
+- ‘increase_contrast’
+- ‘lighter’
+- ‘linear_contrast’
+- ‘medium_contrast’
+- ‘negative’
+- ‘strong_contrast’
+- ‘vintage’
+
+Default is none.
+
- master, m
+Set the master key points. These points will define a second pass mapping. It
+is sometimes called a "luminance" or "value" mapping. It can be used with
+r, g, b or all since it acts like a
+post-processing LUT.
+
- red, r
+Set the key points for the red component.
+
- green, g
+Set the key points for the green component.
+
- blue, b
+Set the key points for the blue component.
+
- all
+Set the key points for all components (not including master).
+Can be used in addition to the other key points component
+options. In this case, the unset component(s) will fallback on this
+all setting.
+
- psfile
+Specify a Photoshop curves file (.acv) to import the settings from.
+
- plot
+Save Gnuplot script of the curves in specified file.
+
- interp
+Specify the kind of interpolation. Available algorithms are:
+
+- ‘natural’
+Natural cubic spline using a piece-wise cubic polynomial that is twice continuously differentiable.
+
- ‘pchip’
+Monotonic cubic spline using a piecewise cubic Hermite interpolating polynomial (PCHIP).
+
+
+
+
+
To avoid some filtergraph syntax conflicts, each key points list need to be
+defined using the following syntax: x0/y0 x1/y1 x2/y2 ....
+
+
+
+
39.52.1 Commands
+
+
This filter supports same commands as options.
+
+
+
+
39.52.2 Examples
+
+
+
+
+
+
+
39.53 datascope
+
+
Video data analysis filter.
+
+
This filter shows hexadecimal pixel values of part of video.
+
+
The filter accepts the following options:
+
+
+- size, s
+Set output video size.
+
+- x
+Set x offset from where to pick pixels.
+
+- y
+Set y offset from where to pick pixels.
+
+- mode
+Set scope mode, can be one of the following:
+
+- ‘mono’
+Draw hexadecimal pixel values with white color on black background.
+
+- ‘color’
+Draw hexadecimal pixel values with input video pixel color on black
+background.
+
+- ‘color2’
+Draw hexadecimal pixel values on color background picked from input video,
+the text color is picked in such way so its always visible.
+
+
+- axis
+Draw rows and columns numbers on left and top of video.
+
+- opacity
+Set background opacity.
+
+- format
+Set display number format. Can be hex, or dec. Default is hex.
+
+- components
+Set pixel components to display. By default all pixel components are displayed.
+
+
+
+
+
39.53.1 Commands
+
+
This filter supports same commands as options excluding size option.
+
+
+
+
+
39.54 dblur
+
Apply Directional blur filter.
+
+
The filter accepts the following options:
+
+
+- angle
+Set angle of directional blur. Default is 45.
+
+- radius
+Set radius of directional blur. Default is 5.
+
+- planes
+Set which planes to filter. By default all planes are filtered.
+
+
+
+
+
39.54.1 Commands
+
This filter supports same commands as options.
+The command accepts the same syntax of the corresponding option.
+
+
If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
39.55 dctdnoiz
+
+
Denoise frames using 2D DCT (frequency domain filtering).
+
+
This filter is not designed for real time.
+
+
The filter accepts the following options:
+
+
+- sigma, s
+Set the noise sigma constant.
+
+This sigma defines a hard threshold of 3 * sigma; every DCT
+coefficient (absolute value) below this threshold with be dropped.
+
+If you need a more advanced filtering, see expr.
+
+Default is 0.
+
+- overlap
+Set number overlapping pixels for each block. Since the filter can be slow, you
+may want to reduce this value, at the cost of a less effective filter and the
+risk of various artefacts.
+
+If the overlapping value doesn’t permit processing the whole input width or
+height, a warning will be displayed and according borders won’t be denoised.
+
+Default value is blocksize-1, which is the best possible setting.
+
+- expr, e
+Set the coefficient factor expression.
+
+For each coefficient of a DCT block, this expression will be evaluated as a
+multiplier value for the coefficient.
+
+If this is option is set, the sigma option will be ignored.
+
+The absolute value of the coefficient can be accessed through the c
+variable.
+
+- n
+Set the blocksize using the number of bits. 1<<n defines the
+blocksize, which is the width and height of the processed blocks.
+
+The default value is 3 (8x8) and can be raised to 4 for a
+blocksize of 16x16. Note that changing this setting has huge consequences
+on the speed processing. Also, a larger block size does not necessarily means a
+better de-noising.
+
+
+
+
+
39.55.1 Examples
+
+
Apply a denoise with a sigma of 4.5:
+
+
+
The same operation can be achieved using the expression system:
+
+
dctdnoiz=e='gte(c, 4.5*3)'
+
+
+
Violent denoise using a block size of 16x16:
+
+
+
+
+
+
39.56 deband
+
+
Remove banding artifacts from input video.
+It works by replacing banded pixels with average value of referenced pixels.
+
+
The filter accepts the following options:
+
+
+- 1thr
+- 2thr
+- 3thr
+- 4thr
+Set banding detection threshold for each plane. Default is 0.02.
+Valid range is 0.00003 to 0.5.
+If difference between current pixel and reference pixel is less than threshold,
+it will be considered as banded.
+
+- range, r
+Banding detection range in pixels. Default is 16. If positive, random number
+in range 0 to set value will be used. If negative, exact absolute value
+will be used.
+The range defines square of four pixels around current pixel.
+
+- direction, d
+Set direction in radians from which four pixel will be compared. If positive,
+random direction from 0 to set direction will be picked. If negative, exact of
+absolute value will be picked. For example direction 0, -PI or -2*PI radians
+will pick only pixels on same row and -PI/2 will pick only pixels on same
+column.
+
+- blur, b
+If enabled, current pixel is compared with average value of all four
+surrounding pixels. The default is enabled. If disabled current pixel is
+compared with all four surrounding pixels. The pixel is considered banded
+if only all four differences with surrounding pixels are less than threshold.
+
+- coupling, c
+If enabled, current pixel is changed if and only if all pixel components are banded,
+e.g. banding detection threshold is triggered for all color components.
+The default is disabled.
+
+
+
+
+
39.56.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.57 deblock
+
+
Remove blocking artifacts from input video.
+
+
The filter accepts the following options:
+
+
+- filter
+Set filter type, can be weak or strong. Default is strong.
+This controls what kind of deblocking is applied.
+
+- block
+Set size of block, allowed range is from 4 to 512. Default is 8.
+
+- alpha
+- beta
+- gamma
+- delta
+Set blocking detection thresholds. Allowed range is 0 to 1.
+Defaults are: 0.098 for alpha and 0.05 for the rest.
+Using higher threshold gives more deblocking strength.
+Setting alpha controls threshold detection at exact edge of block.
+Remaining options controls threshold detection near the edge. Each one for
+below/above or left/right. Setting any of those to 0 disables
+deblocking.
+
+- planes
+Set planes to filter. Default is to filter all available planes.
+
+
+
+
+
39.57.1 Examples
+
+
+- Deblock using weak filter and block size of 4 pixels.
+
+
deblock=filter=weak:block=4
+
- Deblock using strong filter, block size of 4 pixels and custom thresholds for
+deblocking more edges.
+
+
deblock=filter=strong:block=4:alpha=0.12:beta=0.07:gamma=0.06:delta=0.05
+
- Similar as above, but filter only first plane.
+
+
deblock=filter=strong:block=4:alpha=0.12:beta=0.07:gamma=0.06:delta=0.05:planes=1
+
- Similar as above, but filter only second and third plane.
+
+
deblock=filter=strong:block=4:alpha=0.12:beta=0.07:gamma=0.06:delta=0.05:planes=6
+
+
+
+
+
39.57.2 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.58 decimate
+
+
Drop duplicated frames at regular intervals.
+
+
The filter accepts the following options:
+
+
+- cycle
+Set the number of frames from which one will be dropped. Setting this to
+N means one frame in every batch of N frames will be dropped.
+Default is 5.
+
+- dupthresh
+Set the threshold for duplicate detection. If the difference metric for a frame
+is less than or equal to this value, then it is declared as duplicate. Default
+is 1.1
+
+- scthresh
+Set scene change threshold. Default is 15.
+
+- blockx
+- blocky
+Set the size of the x and y-axis blocks used during metric calculations.
+Larger blocks give better noise suppression, but also give worse detection of
+small movements. Must be a power of two. Default is 32.
+
+- ppsrc
+Mark main input as a pre-processed input and activate clean source input
+stream. This allows the input to be pre-processed with various filters to help
+the metrics calculation while keeping the frame selection lossless. When set to
+1, the first stream is for the pre-processed input, and the second
+stream is the clean source from where the kept frames are chosen. Default is
+0.
+
+- chroma
+Set whether or not chroma is considered in the metric calculations. Default is
+1.
+
+- mixed
+Set whether or not the input only partially contains content to be decimated.
+Default is false.
+If enabled video output stream will be in variable frame rate.
+
+
+
+
+
39.59 deconvolve
+
+
Apply 2D deconvolution of video stream in frequency domain using second stream
+as impulse.
+
+
The filter accepts the following options:
+
+
+- planes
+Set which planes to process.
+
+- impulse
+Set which impulse video frames will be processed, can be first
+or all. Default is all.
+
+- noise
+Set noise when doing divisions. Default is 0.0000001. Useful when width
+and height are not same and not power of 2 or if stream prior to convolving
+had noise.
+
+
+
The deconvolve filter also supports the framesync options.
+
+
+
+
39.60 dedot
+
+
Reduce cross-luminance (dot-crawl) and cross-color (rainbows) from video.
+
+
It accepts the following options:
+
+
+- m
+Set mode of operation. Can be combination of dotcrawl for cross-luminance reduction and/or
+rainbows for cross-color reduction.
+
+- lt
+Set spatial luma threshold. Lower values increases reduction of cross-luminance.
+
+- tl
+Set tolerance for temporal luma. Higher values increases reduction of cross-luminance.
+
+- tc
+Set tolerance for chroma temporal variation. Higher values increases reduction of cross-color.
+
+- ct
+Set temporal chroma threshold. Lower values increases reduction of cross-color.
+
+
+
+
+
39.61 deflate
+
+
Apply deflate effect to the video.
+
+
This filter replaces the pixel by the local(3x3) average by taking into account
+only values lower than the pixel.
+
+
It accepts the following options:
+
+
+- threshold0
+- threshold1
+- threshold2
+- threshold3
+Limit the maximum change for each plane, default is 65535.
+If 0, plane will remain unchanged.
+
+
+
+
+
39.61.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.62 deflicker
+
+
Remove temporal frame luminance variations.
+
+
It accepts the following options:
+
+
+- size, s
+Set moving-average filter size in frames. Default is 5. Allowed range is 2 - 129.
+
+- mode, m
+Set averaging mode to smooth temporal luminance variations.
+
+Available values are:
+
+- ‘am’
+Arithmetic mean
+
+- ‘gm’
+Geometric mean
+
+- ‘hm’
+Harmonic mean
+
+- ‘qm’
+Quadratic mean
+
+- ‘cm’
+Cubic mean
+
+- ‘pm’
+Power mean
+
+- ‘median’
+Median
+
+
+- bypass
+Do not actually modify frame. Useful when one only wants metadata.
+
+
+
+
+
39.63 dejudder
+
+
Remove judder produced by partially interlaced telecined content.
+
+
Judder can be introduced, for instance, by pullup filter. If the original
+source was partially telecined content then the output of pullup,dejudder
+will have a variable frame rate. May change the recorded frame rate of the
+container. Aside from that change, this filter will not affect constant frame
+rate video.
+
+
The option available in this filter is:
+
+- cycle
+Specify the length of the window over which the judder repeats.
+
+Accepts any integer greater than 1. Useful values are:
+
+- ‘4’
+If the original was telecined from 24 to 30 fps (Film to NTSC).
+
+- ‘5’
+If the original was telecined from 25 to 30 fps (PAL to NTSC).
+
+- ‘20’
+If a mixture of the two.
+
+
+The default is ‘4’.
+
+
+
+
+
39.64 delogo
+
+
Suppress a TV station logo by a simple interpolation of the surrounding
+pixels. Just set a rectangle covering the logo and watch it disappear
+(and sometimes something even uglier appear - your mileage may vary).
+
+
It accepts the following parameters:
+
+- x
+- y
+Specify the top left corner coordinates of the logo. They must be
+specified.
+
+- w
+- h
+Specify the width and height of the logo to clear. They must be
+specified.
+
+- show
+When set to 1, a green rectangle is drawn on the screen to simplify
+finding the right x, y, w, and h parameters.
+The default value is 0.
+
+The rectangle is drawn on the outermost pixels which will be (partly)
+replaced with interpolated values. The values of the next pixels
+immediately outside this rectangle in each direction will be used to
+compute the interpolated pixel values inside the rectangle.
+
+
+
+
+
+
39.64.1 Examples
+
+
+- Set a rectangle covering the area with top left corner coordinates 0,0
+and size 100x77:
+
+
delogo=x=0:y=0:w=100:h=77
+
+
+
+
+
+
39.65 derain
+
+
Remove the rain in the input image/video by applying the derain methods based on
+convolutional neural networks. Supported models:
+
+
+
+
Training as well as model generation scripts are provided in
+the repository at https://github.com/XueweiMeng/derain_filter.git.
+
+
The filter accepts the following options:
+
+
+- filter_type
+Specify which filter to use. This option accepts the following values:
+
+
+- ‘derain’
+Derain filter. To conduct derain filter, you need to use a derain model.
+
+- ‘dehaze’
+Dehaze filter. To conduct dehaze filter, you need to use a dehaze model.
+
+Default value is ‘derain’.
+
+- dnn_backend
+Specify which DNN backend to use for model loading and execution. This option accepts
+the following values:
+
+
+- ‘tensorflow’
+TensorFlow backend. To enable this backend you
+need to install the TensorFlow for C library (see
+https://www.tensorflow.org/install/lang_c) and configure FFmpeg with
+--enable-libtensorflow
+
+
+- model
+Set path to model file specifying network architecture and its parameters.
+Note that different backends use different file formats. TensorFlow can load files for only its format.
+
+
+
To get full functionality (such as async execution), please use the dnn_processing filter.
+
+
+
+
39.66 deshake
+
+
Attempt to fix small changes in horizontal and/or vertical shift. This
+filter helps remove camera shake from hand-holding a camera, bumping a
+tripod, moving on a vehicle, etc.
+
+
The filter accepts the following options:
+
+
+- x
+- y
+- w
+- h
+Specify a rectangular area where to limit the search for motion
+vectors.
+If desired the search for motion vectors can be limited to a
+rectangular area of the frame defined by its top left corner, width
+and height. These parameters have the same meaning as the drawbox
+filter which can be used to visualise the position of the bounding
+box.
+
+This is useful when simultaneous movement of subjects within the frame
+might be confused for camera motion by the motion vector search.
+
+If any or all of x, y, w and h are set to -1
+then the full frame is used. This allows later options to be set
+without specifying the bounding box for the motion vector search.
+
+Default - search the whole frame.
+
+- rx
+- ry
+Specify the maximum extent of movement in x and y directions in the
+range 0-64 pixels. Default 16.
+
+- edge
+Specify how to generate pixels to fill blanks at the edge of the
+frame. Available values are:
+
+- ‘blank, 0’
+Fill zeroes at blank locations
+
- ‘original, 1’
+Original image at blank locations
+
- ‘clamp, 2’
+Extruded edge value at blank locations
+
- ‘mirror, 3’
+Mirrored edge at blank locations
+
+Default value is ‘mirror’.
+
+- blocksize
+Specify the blocksize to use for motion search. Range 4-128 pixels,
+default 8.
+
+- contrast
+Specify the contrast threshold for blocks. Only blocks with more than
+the specified contrast (difference between darkest and lightest
+pixels) will be considered. Range 1-255, default 125.
+
+- search
+Specify the search strategy. Available values are:
+
+- ‘exhaustive, 0’
+Set exhaustive search
+
- ‘less, 1’
+Set less exhaustive search.
+
+Default value is ‘exhaustive’.
+
+- filename
+If set then a detailed log of the motion search is written to the
+specified file.
+
+
+
+
+
+
39.67 despill
+
+
Remove unwanted contamination of foreground colors, caused by reflected color of
+greenscreen or bluescreen.
+
+
This filter accepts the following options:
+
+
+- type
+Set what type of despill to use.
+
+- mix
+Set how spillmap will be generated.
+
+- expand
+Set how much to get rid of still remaining spill.
+
+- red
+Controls amount of red in spill area.
+
+- green
+Controls amount of green in spill area.
+Should be -1 for greenscreen.
+
+- blue
+Controls amount of blue in spill area.
+Should be -1 for bluescreen.
+
+- brightness
+Controls brightness of spill area, preserving colors.
+
+- alpha
+Modify alpha from generated spillmap.
+
+
+
+
+
39.67.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.68 detelecine
+
+
Apply an exact inverse of the telecine operation. It requires a predefined
+pattern specified using the pattern option which must be the same as that passed
+to the telecine filter.
+
+
This filter accepts the following options:
+
+
+- first_field
+
+- ‘top, t’
+top field first
+
- ‘bottom, b’
+bottom field first
+The default value is top.
+
+
+- pattern
+A string of numbers representing the pulldown pattern you wish to apply.
+The default value is 23.
+
+- start_frame
+A number representing position of the first frame with respect to the telecine
+pattern. This is to be used if the stream is cut. The default value is 0.
+
+
+
+
+
39.69 dilation
+
+
Apply dilation effect to the video.
+
+
This filter replaces the pixel by the local(3x3) maximum.
+
+
It accepts the following options:
+
+
+- threshold0
+- threshold1
+- threshold2
+- threshold3
+Limit the maximum change for each plane, default is 65535.
+If 0, plane will remain unchanged.
+
+- coordinates
+Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
+pixels are used.
+
+Flags to local 3x3 coordinates maps like this:
+
+1 2 3
+ 4 5
+ 6 7 8
+
+
+
+
+
39.69.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.70 displace
+
+
Displace pixels as indicated by second and third input stream.
+
+
It takes three input streams and outputs one stream, the first input is the
+source, and second and third input are displacement maps.
+
+
The second input specifies how much to displace pixels along the
+x-axis, while the third input specifies how much to displace pixels
+along the y-axis.
+If one of displacement map streams terminates, last frame from that
+displacement map will be used.
+
+
Note that once generated, displacements maps can be reused over and over again.
+
+
A description of the accepted options follows.
+
+
+- edge
+Set displace behavior for pixels that are out of range.
+
+Available values are:
+
+- ‘blank’
+Missing pixels are replaced by black pixels.
+
+- ‘smear’
+Adjacent pixels will spread out to replace missing pixels.
+
+- ‘wrap’
+Out of range pixels are wrapped so they point to pixels of other side.
+
+- ‘mirror’
+Out of range pixels will be replaced with mirrored pixels.
+
+Default is ‘smear’.
+
+
+
+
+
+
39.70.1 Examples
+
+
+- Add ripple effect to rgb input of video size hd720:
+
+
ffmpeg -i INPUT -f lavfi -i nullsrc=s=hd720,lutrgb=128:128:128 -f lavfi -i nullsrc=s=hd720,geq='r=128+30*sin(2*PI*X/400+T):g=128+30*sin(2*PI*X/400+T):b=128+30*sin(2*PI*X/400+T)' -lavfi '[0][1][2]displace' OUTPUT
+
- Add wave effect to rgb input of video size hd720:
+
+
ffmpeg -i INPUT -f lavfi -i nullsrc=hd720,geq='r=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T)):g=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T)):b=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T))' -lavfi '[1]split[x][y],[0][x][y]displace' OUTPUT
+
+
+
+
+
+
39.71 dnn_classify
+
+
Do classification with deep neural networks based on bounding boxes.
+
+
The filter accepts the following options:
+
+
+- dnn_backend
+Specify which DNN backend to use for model loading and execution. This option accepts
+only openvino now, tensorflow backends will be added.
+
+- model
+Set path to model file specifying network architecture and its parameters.
+Note that different backends use different file formats.
+
+- input
+Set the input name of the dnn network.
+
+- output
+Set the output name of the dnn network.
+
+- confidence
+Set the confidence threshold (default: 0.5).
+
+- labels
+Set path to label file specifying the mapping between label id and name.
+Each label name is written in one line, tailing spaces and empty lines are skipped.
+The first line is the name of label id 0,
+and the second line is the name of label id 1, etc.
+The label id is considered as name if the label file is not provided.
+
+- backend_configs
+Set the configs to be passed into backend
+
+For tensorflow backend, you can set its configs with sess_config options,
+please use tools/python/tf_sess_config.py to get the configs for your system.
+
+
+
+
+
+
39.72 dnn_detect
+
+
Do object detection with deep neural networks.
+
+
The filter accepts the following options:
+
+
+- dnn_backend
+Specify which DNN backend to use for model loading and execution. This option accepts
+only openvino now, tensorflow backends will be added.
+
+- model
+Set path to model file specifying network architecture and its parameters.
+Note that different backends use different file formats.
+
+- input
+Set the input name of the dnn network.
+
+- output
+Set the output name of the dnn network.
+
+- confidence
+Set the confidence threshold (default: 0.5).
+
+- labels
+Set path to label file specifying the mapping between label id and name.
+Each label name is written in one line, tailing spaces and empty lines are skipped.
+The first line is the name of label id 0 (usually it is ’background’),
+and the second line is the name of label id 1, etc.
+The label id is considered as name if the label file is not provided.
+
+- backend_configs
+Set the configs to be passed into backend. To use async execution, set async (default: set).
+Roll back to sync execution if the backend does not support async.
+
+
+
+
+
+
39.73 dnn_processing
+
+
Do image processing with deep neural networks. It works together with another filter
+which converts the pixel format of the Frame to what the dnn network requires.
+
+
The filter accepts the following options:
+
+
+- dnn_backend
+Specify which DNN backend to use for model loading and execution. This option accepts
+the following values:
+
+
+- ‘tensorflow’
+TensorFlow backend. To enable this backend you
+need to install the TensorFlow for C library (see
+https://www.tensorflow.org/install/lang_c) and configure FFmpeg with
+--enable-libtensorflow
+
+- ‘openvino’
+OpenVINO backend. To enable this backend you
+need to build and install the OpenVINO for C library (see
+https://github.com/openvinotoolkit/openvino/blob/master/build-instruction.md) and configure FFmpeg with
+--enable-libopenvino (–extra-cflags=-I... –extra-ldflags=-L... might
+be needed if the header files and libraries are not installed into system path)
+
+
+
+- model
+Set path to model file specifying network architecture and its parameters.
+Note that different backends use different file formats. TensorFlow, OpenVINO backend can load files for only its format.
+
+- input
+Set the input name of the dnn network.
+
+- output
+Set the output name of the dnn network.
+
+- backend_configs
+Set the configs to be passed into backend. To use async execution, set async (default: set).
+Roll back to sync execution if the backend does not support async.
+
+For tensorflow backend, you can set its configs with sess_config options,
+please use tools/python/tf_sess_config.py to get the configs of TensorFlow backend for your system.
+
+
+
+
+
+
39.73.1 Examples
+
+
+- Remove rain in rgb24 frame with can.pb (see derain filter):
+
+
./ffmpeg -i rain.jpg -vf format=rgb24,dnn_processing=dnn_backend=tensorflow:model=can.pb:input=x:output=y derain.jpg
+
- Handle the Y channel with srcnn.pb (see sr filter) for frame with yuv420p (planar YUV formats supported):
+
+
./ffmpeg -i 480p.jpg -vf format=yuv420p,scale=w=iw*2:h=ih*2,dnn_processing=dnn_backend=tensorflow:model=srcnn.pb:input=x:output=y -y srcnn.jpg
+
- Handle the Y channel with espcn.pb (see sr filter), which changes frame size, for format yuv420p (planar YUV formats supported),
+please use tools/python/tf_sess_config.py to get the configs of TensorFlow backend for your system.
+
+
./ffmpeg -i 480p.jpg -vf format=yuv420p,dnn_processing=dnn_backend=tensorflow:model=espcn.pb:input=x:output=y:backend_configs=sess_config=0x10022805320e09cdccccccccccec3f20012a01303801 -y tmp.espcn.jpg
+
+
+
+
+
+
39.74 drawbox
+
+
Draw a colored box on the input image.
+
+
It accepts the following parameters:
+
+
+- x
+- y
+The expressions which specify the top left corner coordinates of the box. It defaults to 0.
+
+- width, w
+- height, h
+The expressions which specify the width and height of the box; if 0 they are interpreted as
+the input width and height. It defaults to 0.
+
+- color, c
+Specify the color of the box to write. For the general syntax of this option,
+check the (ffmpeg-utils)"Color" section in the ffmpeg-utils manual. If the special
+value invert is used, the box edge color is the same as the
+video with inverted luma.
+
+- thickness, t
+The expression which sets the thickness of the box edge.
+A value of fill will create a filled box. Default value is 3.
+
+See below for the list of accepted constants.
+
+- replace
+Applicable if the input has alpha. With value 1, the pixels of the painted box
+will overwrite the video’s color and alpha pixels.
+Default is 0, which composites the box onto the input, leaving the video’s alpha intact.
+
+
+
The parameters for x, y, w and h and t are expressions containing the
+following constants:
+
+
+- dar
+The input display aspect ratio, it is the same as (w / h) * sar.
+
+- hsub
+- vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" hsub is 2 and vsub is 1.
+
+- in_h, ih
+- in_w, iw
+The input width and height.
+
+- sar
+The input sample aspect ratio.
+
+- x
+- y
+The x and y offset coordinates where the box is drawn.
+
+- w
+- h
+The width and height of the drawn box.
+
+- box_source
+Box source can be set as side_data_detection_bboxes if you want to use box data in
+detection bboxes of side data.
+
+If box_source is set, the x, y, width and height will be ignored and
+still use box data in detection bboxes of side data. So please do not use this parameter if you were
+not sure about the box source.
+
+- t
+The thickness of the drawn box.
+
+These constants allow the x, y, w, h and t expressions to refer to
+each other, so you may for example specify y=x/dar or h=w/dar.
+
+
+
+
+
+
39.74.1 Examples
+
+
+
+
+
+
39.74.2 Commands
+
This filter supports same commands as options.
+The command accepts the same syntax of the corresponding option.
+
+
If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
39.75 drawgraph
+
Draw a graph using input video metadata.
+
+
It accepts the following parameters:
+
+
+- m1
+Set 1st frame metadata key from which metadata values will be used to draw a graph.
+
+- fg1
+Set 1st foreground color expression.
+
+- m2
+Set 2nd frame metadata key from which metadata values will be used to draw a graph.
+
+- fg2
+Set 2nd foreground color expression.
+
+- m3
+Set 3rd frame metadata key from which metadata values will be used to draw a graph.
+
+- fg3
+Set 3rd foreground color expression.
+
+- m4
+Set 4th frame metadata key from which metadata values will be used to draw a graph.
+
+- fg4
+Set 4th foreground color expression.
+
+- min
+Set minimal value of metadata value.
+
+- max
+Set maximal value of metadata value.
+
+- bg
+Set graph background color. Default is white.
+
+- mode
+Set graph mode.
+
+Available values for mode is:
+
+- ‘bar’
+- ‘dot’
+- ‘line’
+
+
+Default is line.
+
+- slide
+Set slide mode.
+
+Available values for slide is:
+
+- ‘frame’
+Draw new frame when right border is reached.
+
+- ‘replace’
+Replace old columns with new ones.
+
+- ‘scroll’
+Scroll from right to left.
+
+- ‘rscroll’
+Scroll from left to right.
+
+- ‘picture’
+Draw single picture.
+
+
+Default is frame.
+
+- size
+Set size of graph video. For the syntax of this option, check the
+(ffmpeg-utils)"Video size" section in the ffmpeg-utils manual.
+The default value is 900x256.
+
+- rate, r
+Set the output frame rate. Default value is 25.
+
+The foreground color expressions can use the following variables:
+
+- MIN
+Minimal value of metadata value.
+
+- MAX
+Maximal value of metadata value.
+
+- VAL
+Current metadata key value.
+
+
+The color is defined as 0xAABBGGRR.
+
+
+
Example using metadata from signalstats filter:
+
+
signalstats,drawgraph=lavfi.signalstats.YAVG:min=0:max=255
+
+
+
Example using metadata from ebur128 filter:
+
+
ebur128=metadata=1,adrawgraph=lavfi.r128.M:min=-120:max=5
+
+
+
+
+
39.76 drawgrid
+
+
Draw a grid on the input image.
+
+
It accepts the following parameters:
+
+
+- x
+- y
+The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
+
+- width, w
+- height, h
+The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
+input width and height, respectively, minus thickness, so image gets
+framed. Default to 0.
+
+- color, c
+Specify the color of the grid. For the general syntax of this option,
+check the (ffmpeg-utils)"Color" section in the ffmpeg-utils manual. If the special
+value invert is used, the grid color is the same as the
+video with inverted luma.
+
+- thickness, t
+The expression which sets the thickness of the grid line. Default value is 1.
+
+See below for the list of accepted constants.
+
+- replace
+Applicable if the input has alpha. With 1 the pixels of the painted grid
+will overwrite the video’s color and alpha pixels.
+Default is 0, which composites the grid onto the input, leaving the video’s alpha intact.
+
+
+
The parameters for x, y, w and h and t are expressions containing the
+following constants:
+
+
+- dar
+The input display aspect ratio, it is the same as (w / h) * sar.
+
+- hsub
+- vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" hsub is 2 and vsub is 1.
+
+- in_h, ih
+- in_w, iw
+The input grid cell width and height.
+
+- sar
+The input sample aspect ratio.
+
+- x
+- y
+The x and y coordinates of some point of grid intersection (meant to configure offset).
+
+- w
+- h
+The width and height of the drawn cell.
+
+- t
+The thickness of the drawn cell.
+
+These constants allow the x, y, w, h and t expressions to refer to
+each other, so you may for example specify y=x/dar or h=w/dar.
+
+
+
+
+
+
39.76.1 Examples
+
+
+- Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
+
+
drawgrid=width=100:height=100:thickness=2:color=red@0.5
+
- Draw a white 3x3 grid with an opacity of 50%:
+
+
drawgrid=w=iw/3:h=ih/3:t=2:c=white@0.5
+
+
+
+
+
39.76.2 Commands
+
This filter supports same commands as options.
+The command accepts the same syntax of the corresponding option.
+
+
If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
39.77 drawtext
+
+
Draw a text string or text from a specified file on top of a video, using the
+libfreetype library.
+
+
To enable compilation of this filter, you need to configure FFmpeg with
+--enable-libfreetype.
+To enable default font fallback and the font option you need to
+configure FFmpeg with --enable-libfontconfig.
+To enable the text_shaping option, you need to configure FFmpeg with
+--enable-libfribidi.
+
+
+
+
39.77.1 Syntax
+
+
It accepts the following parameters:
+
+
+- box
+Used to draw a box around text using the background color.
+The value must be either 1 (enable) or 0 (disable).
+The default value of box is 0.
+
+- boxborderw
+Set the width of the border to be drawn around the box using boxcolor.
+The default value of boxborderw is 0.
+
+- boxcolor
+The color to be used for drawing box around text. For the syntax of this
+option, check the (ffmpeg-utils)"Color" section in the ffmpeg-utils manual.
+
+The default value of boxcolor is "white".
+
+- line_spacing
+Set the line spacing in pixels of the border to be drawn around the box using box.
+The default value of line_spacing is 0.
+
+- borderw
+Set the width of the border to be drawn around the text using bordercolor.
+The default value of borderw is 0.
+
+- bordercolor
+Set the color to be used for drawing border around text. For the syntax of this
+option, check the (ffmpeg-utils)"Color" section in the ffmpeg-utils manual.
+
+The default value of bordercolor is "black".
+
+- expansion
+Select how the text is expanded. Can be either none,
+strftime (deprecated) or normal (default). See the
+Text expansion section below for details.
+
+- basetime
+Set a start time for the count. Value is in microseconds. Only applied
+in the deprecated strftime expansion mode. To emulate in normal expansion
+mode use the pts function, supplying the start time (in seconds)
+as the second argument.
+
+- fix_bounds
+If true, check and fix text coords to avoid clipping.
+
+- fontcolor
+The color to be used for drawing fonts. For the syntax of this option, check
+the (ffmpeg-utils)"Color" section in the ffmpeg-utils manual.
+
+The default value of fontcolor is "black".
+
+- fontcolor_expr
+String which is expanded the same way as text to obtain dynamic
+fontcolor value. By default this option has empty value and is not
+processed. When this option is set, it overrides fontcolor option.
+
+- font
+The font family to be used for drawing text. By default Sans.
+
+- fontfile
+The font file to be used for drawing text. The path must be included.
+This parameter is mandatory if the fontconfig support is disabled.
+
+- alpha
+Draw the text applying alpha blending. The value can
+be a number between 0.0 and 1.0.
+The expression accepts the same variables x, y as well.
+The default value is 1.
+Please see fontcolor_expr.
+
+- fontsize
+The font size to be used for drawing text.
+The default value of fontsize is 16.
+
+- text_shaping
+If set to 1, attempt to shape the text (for example, reverse the order of
+right-to-left text and join Arabic characters) before drawing it.
+Otherwise, just draw the text exactly as given.
+By default 1 (if supported).
+
+- ft_load_flags
+The flags to be used for loading the fonts.
+
+The flags map the corresponding flags supported by libfreetype, and are
+a combination of the following values:
+
+- default
+- no_scale
+- no_hinting
+- render
+- no_bitmap
+- vertical_layout
+- force_autohint
+- crop_bitmap
+- pedantic
+- ignore_global_advance_width
+- no_recurse
+- ignore_transform
+- monochrome
+- linear_design
+- no_autohint
+
+
+Default value is "default".
+
+For more information consult the documentation for the FT_LOAD_*
+libfreetype flags.
+
+- shadowcolor
+The color to be used for drawing a shadow behind the drawn text. For the
+syntax of this option, check the (ffmpeg-utils)"Color" section in the
+ffmpeg-utils manual.
+
+The default value of shadowcolor is "black".
+
+- shadowx
+- shadowy
+The x and y offsets for the text shadow position with respect to the
+position of the text. They can be either positive or negative
+values. The default value for both is "0".
+
+- start_number
+The starting frame number for the n/frame_num variable. The default value
+is "0".
+
+- tabsize
+The size in number of spaces to use for rendering the tab.
+Default value is 4.
+
+- timecode
+Set the initial timecode representation in "hh:mm:ss[:;.]ff"
+format. It can be used with or without text parameter. timecode_rate
+option must be specified.
+
+- timecode_rate, rate, r
+Set the timecode frame rate (timecode only). Value will be rounded to nearest
+integer. Minimum value is "1".
+Drop-frame timecode is supported for frame rates 30 & 60.
+
+- tc24hmax
+If set to 1, the output of the timecode option will wrap around at 24 hours.
+Default is 0 (disabled).
+
+- text
+The text string to be drawn. The text must be a sequence of UTF-8
+encoded characters.
+This parameter is mandatory if no file is specified with the parameter
+textfile.
+
+- textfile
+A text file containing text to be drawn. The text must be a sequence
+of UTF-8 encoded characters.
+
+This parameter is mandatory if no text string is specified with the
+parameter text.
+
+If both text and textfile are specified, an error is thrown.
+
+- text_source
+Text source should be set as side_data_detection_bboxes if you want to use text data in
+detection bboxes of side data.
+
+If text source is set, text and textfile will be ignored and still use
+text data in detection bboxes of side data. So please do not use this parameter
+if you are not sure about the text source.
+
+- reload
+The textfile will be reloaded at specified frame interval.
+Be sure to update textfile atomically, or it may be read partially,
+or even fail.
+Range is 0 to INT_MAX. Default is 0.
+
+- x
+- y
+The expressions which specify the offsets where text will be drawn
+within the video frame. They are relative to the top/left border of the
+output image.
+
+The default value of x and y is "0".
+
+See below for the list of accepted constants and functions.
+
+
+
The parameters for x and y are expressions containing the
+following constants and functions:
+
+
+- dar
+input display aspect ratio, it is the same as (w / h) * sar
+
+- hsub
+- vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" hsub is 2 and vsub is 1.
+
+- line_h, lh
+the height of each text line
+
+- main_h, h, H
+the input height
+
+- main_w, w, W
+the input width
+
+- max_glyph_a, ascent
+the maximum distance from the baseline to the highest/upper grid
+coordinate used to place a glyph outline point, for all the rendered
+glyphs.
+It is a positive value, due to the grid’s orientation with the Y axis
+upwards.
+
+- max_glyph_d, descent
+the maximum distance from the baseline to the lowest grid coordinate
+used to place a glyph outline point, for all the rendered glyphs.
+This is a negative value, due to the grid’s orientation, with the Y axis
+upwards.
+
+- max_glyph_h
+maximum glyph height, that is the maximum height for all the glyphs
+contained in the rendered text, it is equivalent to ascent -
+descent.
+
+- max_glyph_w
+maximum glyph width, that is the maximum width for all the glyphs
+contained in the rendered text
+
+- n
+the number of input frame, starting from 0
+
+- rand(min, max)
+return a random number included between min and max
+
+- sar
+The input sample aspect ratio.
+
+- t
+timestamp expressed in seconds, NAN if the input timestamp is unknown
+
+- text_h, th
+the height of the rendered text
+
+- text_w, tw
+the width of the rendered text
+
+- x
+- y
+the x and y offset coordinates where the text is drawn.
+
+These parameters allow the x and y expressions to refer
+to each other, so you can for example specify y=x/dar.
+
+- pict_type
+A one character description of the current frame’s picture type.
+
+- pkt_pos
+The current packet’s position in the input file or stream
+(in bytes, from the start of the input). A value of -1 indicates
+this info is not available.
+
+- duration
+The current packet’s duration, in seconds.
+
+- pkt_size
+The current packet’s size (in bytes).
+
+
+
+
+
39.77.2 Text expansion
+
+
If expansion is set to strftime, the filter recognizes
+sequences accepted by the strftime C function in the provided
+text and expands them accordingly. Check the documentation of
+strftime. This feature is deprecated in favor of normal
+expansion with the gmtime or localtime expansion
+functions.
+
+
If expansion is set to none, the text is printed verbatim.
+
+
If expansion is set to normal (which is the default),
+the following expansion mechanism is used.
+
+
The backslash character ‘\’, followed by any character, always expands to
+the second character.
+
+
Sequences of the form %{...} are expanded. The text between the
+braces is a function name, possibly followed by arguments separated by ’:’.
+If the arguments contain special characters or delimiters (’:’ or ’}’),
+they should be escaped.
+
+
Note that they probably must also be escaped as the value for the text
+option in the filter argument string and as the filter argument in the
+filtergraph description, and possibly also for the shell, that makes up to four
+levels of escaping; using a text file with the textfile option avoids
+these problems.
+
+
The following functions are available:
+
+
+expr, eThe expression evaluation result.
+
+It must take one argument specifying the expression to be evaluated,
+which accepts the same constants and functions as the x and
+y values. Note that not all constants should be used, for
+example the text size is not known when evaluating the expression, so
+the constants text_w and text_h will have an undefined
+value.
+
+expr_int_format, eifEvaluate the expression’s value and output as formatted integer.
+
+The first argument is the expression to be evaluated, just as for the expr function.
+The second argument specifies the output format. Allowed values are ‘x’,
+‘X’, ‘d’ and ‘u’. They are treated exactly as in the
+printf function.
+The third parameter is optional and sets the number of positions taken by the output.
+It can be used to add padding with zeros from the left.
+
+gmtimeThe time at which the filter is running, expressed in UTC.
+It can accept an argument: a strftime C function format string.
+The format string is extended to support the variable %[1-6]N
+which prints fractions of the second with optionally specified number of digits.
+
+localtimeThe time at which the filter is running, expressed in the local time zone.
+It can accept an argument: a strftime C function format string.
+The format string is extended to support the variable %[1-6]N
+which prints fractions of the second with optionally specified number of digits.
+
+metadataFrame metadata. Takes one or two arguments.
+
+The first argument is mandatory and specifies the metadata key.
+
+The second argument is optional and specifies a default value, used when the
+metadata key is not found or empty.
+
+Available metadata can be identified by inspecting entries
+starting with TAG included within each frame section
+printed by running ffprobe -show_frames.
+
+String metadata generated in filters leading to
+the drawtext filter are also available.
+
+n, frame_numThe frame number, starting from 0.
+
+pict_typeA one character description of the current picture type.
+
+ptsThe timestamp of the current frame.
+It can take up to three arguments.
+
+The first argument is the format of the timestamp; it defaults to flt
+for seconds as a decimal number with microsecond accuracy; hms stands
+for a formatted [-]HH:MM:SS.mmm timestamp with millisecond accuracy.
+gmtime stands for the timestamp of the frame formatted as UTC time;
+localtime stands for the timestamp of the frame formatted as
+local time zone time.
+
+The second argument is an offset added to the timestamp.
+
+If the format is set to hms, a third argument 24HH may be
+supplied to present the hour part of the formatted timestamp in 24h format
+(00-23).
+
+If the format is set to localtime or gmtime, a third
+argument may be supplied: a strftime C function format string.
+By default, YYYY-MM-DD HH:MM:SS format will be used.
+
+
+
+
+
39.77.3 Commands
+
+
This filter supports altering parameters via commands:
+
+- reinit
+Alter existing filter parameters.
+
+Syntax for the argument is the same as for filter invocation, e.g.
+
+
+
fontsize=56:fontcolor=green:text='Hello World'
+
Full filter invocation with sendcmd would look like this:
+
+
+
sendcmd=c='56.0 drawtext reinit fontsize=56\:fontcolor=green\:text=Hello\\ World'
+
+
+
If the entire argument can’t be parsed or applied as valid values then the filter will
+continue with its existing parameters.
+
+
+
+
+
+
39.78 edgedetect
+
+
Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
+
+
The filter accepts the following options:
+
+
+- low
+- high
+Set low and high threshold values used by the Canny thresholding
+algorithm.
+
+The high threshold selects the "strong" edge pixels, which are then
+connected through 8-connectivity with the "weak" edge pixels selected
+by the low threshold.
+
+low and high threshold values must be chosen in the range
+[0,1], and low should be lesser or equal to high.
+
+Default value for low is 20/255, and default value for high
+is 50/255.
+
+- mode
+Define the drawing mode.
+
+
+- ‘wires’
+Draw white/gray wires on black background.
+
+- ‘colormix’
+Mix the colors to create a paint/cartoon effect.
+
+- ‘canny’
+Apply Canny edge detector on all selected planes.
+
+Default value is wires.
+
+- planes
+Select planes for filtering. By default all available planes are filtered.
+
+
+
+
+
39.78.1 Examples
+
+
+- Standard edge detection with custom values for the hysteresis thresholding:
+
+
edgedetect=low=0.1:high=0.4
+
- Painting effect without thresholding:
+
+
edgedetect=mode=colormix:high=0
+
+
+
+
+
+
39.79 elbg
+
+
Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
+
+
For each input image, the filter will compute the optimal mapping from
+the input to the output given the codebook length, that is the number
+of distinct output colors.
+
+
This filter accepts the following options.
+
+
+- codebook_length, l
+Set codebook length. The value must be a positive integer, and
+represents the number of distinct output colors. Default value is 256.
+
+- nb_steps, n
+Set the maximum number of iterations to apply for computing the optimal
+mapping. The higher the value the better the result and the higher the
+computation time. Default value is 1.
+
+- seed, s
+Set a random seed, must be an integer included between 0 and
+UINT32_MAX. If not specified, or if explicitly set to -1, the filter
+will try to use a good random seed on a best effort basis.
+
+- pal8
+Set pal8 output pixel format. This option does not work with codebook
+length greater than 256. Default is disabled.
+
+- use_alpha
+Include alpha values in the quantization calculation. Allows creating
+palettized output images (e.g. PNG8) with multiple alpha smooth blending.
+
+
+
+
+
39.80 entropy
+
+
Measure graylevel entropy in histogram of color channels of video frames.
+
+
It accepts the following parameters:
+
+
+- mode
+Can be either normal or diff. Default is normal.
+
+diff mode measures entropy of histogram delta values, absolute differences
+between neighbour histogram values.
+
+
+
+
+
39.81 epx
+
Apply the EPX magnification filter which is designed for pixel art.
+
+
It accepts the following option:
+
+
+- n
+Set the scaling dimension: 2 for 2xEPX, 3 for
+3xEPX.
+Default is 3.
+
+
+
+
+
39.82 eq
+
Set brightness, contrast, saturation and approximate gamma adjustment.
+
+
The filter accepts the following options:
+
+
+- contrast
+Set the contrast expression. The value must be a float value in range
+-1000.0 to 1000.0. The default value is "1".
+
+- brightness
+Set the brightness expression. The value must be a float value in
+range -1.0 to 1.0. The default value is "0".
+
+- saturation
+Set the saturation expression. The value must be a float in
+range 0.0 to 3.0. The default value is "1".
+
+- gamma
+Set the gamma expression. The value must be a float in range
+0.1 to 10.0. The default value is "1".
+
+- gamma_r
+Set the gamma expression for red. The value must be a float in
+range 0.1 to 10.0. The default value is "1".
+
+- gamma_g
+Set the gamma expression for green. The value must be a float in range
+0.1 to 10.0. The default value is "1".
+
+- gamma_b
+Set the gamma expression for blue. The value must be a float in range
+0.1 to 10.0. The default value is "1".
+
+- gamma_weight
+Set the gamma weight expression. It can be used to reduce the effect
+of a high gamma value on bright image areas, e.g. keep them from
+getting overamplified and just plain white. The value must be a float
+in range 0.0 to 1.0. A value of 0.0 turns the
+gamma correction all the way down while 1.0 leaves it at its
+full strength. Default is "1".
+
+- eval
+Set when the expressions for brightness, contrast, saturation and
+gamma expressions are evaluated.
+
+It accepts the following values:
+
+- ‘init’
+only evaluate expressions once during the filter initialization or
+when a command is processed
+
+- ‘frame’
+evaluate expressions for each incoming frame
+
+
+Default value is ‘init’.
+
+
+
The expressions accept the following parameters:
+
+- n
+frame count of the input frame starting from 0
+
+- pos
+byte position of the corresponding packet in the input file, NAN if
+unspecified; deprecated, do not use
+
+- r
+frame rate of the input video, NAN if the input frame rate is unknown
+
+- t
+timestamp expressed in seconds, NAN if the input timestamp is unknown
+
+
+
+
+
39.82.1 Commands
+
The filter supports the following commands:
+
+
+- contrast
+Set the contrast expression.
+
+- brightness
+Set the brightness expression.
+
+- saturation
+Set the saturation expression.
+
+- gamma
+Set the gamma expression.
+
+- gamma_r
+Set the gamma_r expression.
+
+- gamma_g
+Set gamma_g expression.
+
+- gamma_b
+Set gamma_b expression.
+
+- gamma_weight
+Set gamma_weight expression.
+
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
+
+
39.83 erosion
+
+
Apply erosion effect to the video.
+
+
This filter replaces the pixel by the local(3x3) minimum.
+
+
It accepts the following options:
+
+
+- threshold0
+- threshold1
+- threshold2
+- threshold3
+Limit the maximum change for each plane, default is 65535.
+If 0, plane will remain unchanged.
+
+- coordinates
+Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
+pixels are used.
+
+Flags to local 3x3 coordinates maps like this:
+
+1 2 3
+ 4 5
+ 6 7 8
+
+
+
+
+
39.83.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.84 estdif
+
+
Deinterlace the input video ("estdif" stands for "Edge Slope
+Tracing Deinterlacing Filter").
+
+
Spatial only filter that uses edge slope tracing algorithm
+to interpolate missing lines.
+It accepts the following parameters:
+
+
+- mode
+The interlacing mode to adopt. It accepts one of the following values:
+
+
+- frame
+Output one frame for each frame.
+
- field
+Output one frame for each field.
+
+
+The default value is field.
+
+- parity
+The picture field parity assumed for the input interlaced video. It accepts one
+of the following values:
+
+
+- tff
+Assume the top field is first.
+
- bff
+Assume the bottom field is first.
+
- auto
+Enable automatic detection of field parity.
+
+
+The default value is auto.
+If the interlacing is unknown or the decoder does not export this information,
+top field first will be assumed.
+
+- deint
+Specify which frames to deinterlace. Accepts one of the following
+values:
+
+
+- all
+Deinterlace all frames.
+
- interlaced
+Only deinterlace frames marked as interlaced.
+
+
+The default value is all.
+
+- rslope
+Specify the search radius for edge slope tracing. Default value is 1.
+Allowed range is from 1 to 15.
+
+- redge
+Specify the search radius for best edge matching. Default value is 2.
+Allowed range is from 0 to 15.
+
+- ecost
+Specify the edge cost for edge matching. Default value is 2.
+Allowed range is from 0 to 50.
+
+- mcost
+Specify the middle cost for edge matching. Default value is 1.
+Allowed range is from 0 to 50.
+
+- dcost
+Specify the distance cost for edge matching. Default value is 1.
+Allowed range is from 0 to 50.
+
+- interp
+Specify the interpolation used. Default is 4-point interpolation. It accepts one
+of the following values:
+
+
+- 2p
+Two-point interpolation.
+
- 4p
+Four-point interpolation.
+
- 6p
+Six-point interpolation.
+
+
+
+
+
+
39.84.1 Commands
+
This filter supports same commands as options.
+
+
+
+
+
39.85 exposure
+
Adjust exposure of the video stream.
+
+
The filter accepts the following options:
+
+
+- exposure
+Set the exposure correction in EV. Allowed range is from -3.0 to 3.0 EV
+Default value is 0 EV.
+
+- black
+Set the black level correction. Allowed range is from -1.0 to 1.0.
+Default value is 0.
+
+
+
+
+
39.85.1 Commands
+
+
This filter supports same commands as options.
+
+
+
+
+
+
39.87 fade
+
+
Apply a fade-in/out effect to the input video.
+
+
It accepts the following parameters:
+
+
+- type, t
+The effect type can be either "in" for a fade-in, or "out" for a fade-out
+effect.
+Default is in.
+
+- start_frame, s
+Specify the number of the frame to start applying the fade
+effect at. Default is 0.
+
+- nb_frames, n
+The number of frames that the fade effect lasts. At the end of the
+fade-in effect, the output video will have the same intensity as the input video.
+At the end of the fade-out transition, the output video will be filled with the
+selected color.
+Default is 25.
+
+- alpha
+If set to 1, fade only alpha channel, if one exists on the input.
+Default value is 0.
+
+- start_time, st
+Specify the timestamp (in seconds) of the frame to start to apply the fade
+effect. If both start_frame and start_time are specified, the fade will start at
+whichever comes last. Default is 0.
+
+- duration, d
+The number of seconds for which the fade effect has to last. At the end of the
+fade-in effect the output video will have the same intensity as the input video,
+at the end of the fade-out transition the output video will be filled with the
+selected color.
+If both duration and nb_frames are specified, duration is used. Default is 0
+(nb_frames is used by default).
+
+- color, c
+Specify the color of the fade. Default is "black".
+
+
+
+
+
39.87.1 Examples
+
+
+
+
+
+
+
39.88 feedback
+
Apply feedback video filter.
+
+
This filter pass cropped input frames to 2nd output.
+From there it can be filtered with other video filters.
+After filter receives frame from 2nd input, that frame
+is combined on top of original frame from 1st input and passed
+to 1st output.
+
+
The typical usage is filter only part of frame.
+
+
The filter accepts the following options:
+
+- x
+- y
+Set the top left crop position.
+
+- w
+- h
+Set the crop size.
+
+
+
+
+
39.88.1 Examples
+
+
+- Blur only top left rectangular part of video frame size 100x100 with gblur filter.
+
+
[in][blurin]feedback=x=0:y=0:w=100:h=100[out][blurout];[blurout]gblur=8[blurin]
+
- Draw black box on top left part of video frame of size 100x100 with drawbox filter.
+
+
[in][blurin]feedback=x=0:y=0:w=100:h=100[out][blurout];[blurout]drawbox=x=0:y=0:w=100:h=100:t=100[blurin]
+
+
+
+
+
+
39.89 fftdnoiz
+
Denoise frames using 3D FFT (frequency domain filtering).
+
+
The filter accepts the following options:
+
+
+- sigma
+Set the noise sigma constant. This sets denoising strength.
+Default value is 1. Allowed range is from 0 to 30.
+Using very high sigma with low overlap may give blocking artifacts.
+
+- amount
+Set amount of denoising. By default all detected noise is reduced.
+Default value is 1. Allowed range is from 0 to 1.
+
+- block
+Set size of block in pixels, Default is 32, can be 8 to 256.
+
+- overlap
+Set block overlap. Default is 0.5. Allowed range is from 0.2 to 0.8.
+
+- method
+Set denoising method. Default is wiener, can also be hard.
+
+- prev
+Set number of previous frames to use for denoising. By default is set to 0.
+
+- next
+Set number of next frames to to use for denoising. By default is set to 0.
+
+- planes
+Set planes which will be filtered, by default are all available filtered
+except alpha.
+
+
+
+
+
39.90 fftfilt
+
Apply arbitrary expressions to samples in frequency domain
+
+
+- dc_Y
+Adjust the dc value (gain) of the luma plane of the image. The filter
+accepts an integer value in range 0 to 1000. The default
+value is set to 0.
+
+- dc_U
+Adjust the dc value (gain) of the 1st chroma plane of the image. The
+filter accepts an integer value in range 0 to 1000. The
+default value is set to 0.
+
+- dc_V
+Adjust the dc value (gain) of the 2nd chroma plane of the image. The
+filter accepts an integer value in range 0 to 1000. The
+default value is set to 0.
+
+- weight_Y
+Set the frequency domain weight expression for the luma plane.
+
+- weight_U
+Set the frequency domain weight expression for the 1st chroma plane.
+
+- weight_V
+Set the frequency domain weight expression for the 2nd chroma plane.
+
+- eval
+Set when the expressions are evaluated.
+
+It accepts the following values:
+
+- ‘init’
+Only evaluate expressions once during the filter initialization.
+
+- ‘frame’
+Evaluate expressions for each incoming frame.
+
+
+Default value is ‘init’.
+
+The filter accepts the following variables:
+
- X
+- Y
+The coordinates of the current sample.
+
+- W
+- H
+The width and height of the image.
+
+- N
+The number of input frame, starting from 0.
+
+- WS
+- HS
+The size of FFT array for horizontal and vertical processing.
+
+
+
+
+
39.90.1 Examples
+
+
+- High-pass:
+
+
fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
+
- Low-pass:
+
+
fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
+
- Sharpen:
+
+
fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
+
- Blur:
+
+
fftfilt=dc_Y=0:weight_Y='exp(-4 * ((Y+X)/(W+H)))'
+
+
+
+
+
+
39.91 field
+
+
Extract a single field from an interlaced image using stride
+arithmetic to avoid wasting CPU time. The output frames are marked as
+non-interlaced.
+
+
The filter accepts the following options:
+
+
+- type
+Specify whether to extract the top (if the value is 0 or
+top) or the bottom field (if the value is 1 or
+bottom).
+
+
+
+
+
39.92 fieldhint
+
+
Create new frames by copying the top and bottom fields from surrounding frames
+supplied as numbers by the hint file.
+
+
+- hint
+Set file containing hints: absolute/relative frame numbers.
+
+There must be one line for each frame in a clip. Each line must contain two
+numbers separated by the comma, optionally followed by - or +.
+Numbers supplied on each line of file can not be out of [N-1,N+1] where N
+is current frame number for absolute mode or out of [-1, 1] range
+for relative mode. First number tells from which frame to pick up top
+field and second number tells from which frame to pick up bottom field.
+
+If optionally followed by + output frame will be marked as interlaced,
+else if followed by - output frame will be marked as progressive, else
+it will be marked same as input frame.
+If optionally followed by t output frame will use only top field, or in
+case of b it will use only bottom field.
+If line starts with # or ; that line is skipped.
+
+- mode
+Can be item absolute or relative or pattern. Default is absolute.
+The pattern mode is same as relative mode, except at last entry of file if there
+are more frames to process than hint file is seek back to start.
+
+
+
Example of first several lines of hint file for relative mode:
+
+
0,0 - # first frame
+1,0 - # second frame, use third's frame top field and second's frame bottom field
+1,0 - # third frame, use fourth's frame top field and third's frame bottom field
+1,0 -
+0,0 -
+0,0 -
+1,0 -
+1,0 -
+1,0 -
+0,0 -
+0,0 -
+1,0 -
+1,0 -
+1,0 -
+0,0 -
+
+
+
+
+
39.93 fieldmatch
+
+
Field matching filter for inverse telecine. It is meant to reconstruct the
+progressive frames from a telecined stream. The filter does not drop duplicated
+frames, so to achieve a complete inverse telecine fieldmatch needs to be
+followed by a decimation filter such as decimate in the filtergraph.
+
+
The separation of the field matching and the decimation is notably motivated by
+the possibility of inserting a de-interlacing filter fallback between the two.
+If the source has mixed telecined and real interlaced content,
+fieldmatch will not be able to match fields for the interlaced parts.
+But these remaining combed frames will be marked as interlaced, and thus can be
+de-interlaced by a later filter such as yadif before decimation.
+
+
In addition to the various configuration options, fieldmatch can take an
+optional second stream, activated through the ppsrc option. If
+enabled, the frames reconstruction will be based on the fields and frames from
+this second stream. This allows the first input to be pre-processed in order to
+help the various algorithms of the filter, while keeping the output lossless
+(assuming the fields are matched properly). Typically, a field-aware denoiser,
+or brightness/contrast adjustments can help.
+
+
Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
+and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
+which fieldmatch is based on. While the semantic and usage are very
+close, some behaviour and options names can differ.
+
+
The decimate filter currently only works for constant frame rate input.
+If your input has mixed telecined (30fps) and progressive content with a lower
+framerate like 24fps use the following filterchain to produce the necessary cfr
+stream: dejudder,fps=30000/1001,fieldmatch,decimate.
+
+
The filter accepts the following options:
+
+
+- order
+Specify the assumed field order of the input stream. Available values are:
+
+
+- ‘auto’
+Auto detect parity (use FFmpeg’s internal parity value).
+
- ‘bff’
+Assume bottom field first.
+
- ‘tff’
+Assume top field first.
+
+
+Note that it is sometimes recommended not to trust the parity announced by the
+stream.
+
+Default value is auto.
+
+- mode
+Set the matching mode or strategy to use. pc mode is the safest in the
+sense that it won’t risk creating jerkiness due to duplicate frames when
+possible, but if there are bad edits or blended fields it will end up
+outputting combed frames when a good match might actually exist. On the other
+hand, pcn_ub mode is the most risky in terms of creating jerkiness,
+but will almost always find a good frame if there is one. The other values are
+all somewhere in between pc and pcn_ub in terms of risking
+jerkiness and creating duplicate frames versus finding good matches in sections
+with bad edits, orphaned fields, blended fields, etc.
+
+More details about p/c/n/u/b are available in p/c/n/u/b meaning section.
+
+Available values are:
+
+
+- ‘pc’
+2-way matching (p/c)
+
- ‘pc_n’
+2-way matching, and trying 3rd match if still combed (p/c + n)
+
- ‘pc_u’
+2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
+
- ‘pc_n_ub’
+2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
+still combed (p/c + n + u/b)
+
- ‘pcn’
+3-way matching (p/c/n)
+
- ‘pcn_ub’
+3-way matching, and trying 4th/5th matches if all 3 of the original matches are
+detected as combed (p/c/n + u/b)
+
+
+The parenthesis at the end indicate the matches that would be used for that
+mode assuming order=tff (and field on auto or
+top).
+
+In terms of speed pc mode is by far the fastest and pcn_ub is
+the slowest.
+
+Default value is pc_n.
+
+- ppsrc
+Mark the main input stream as a pre-processed input, and enable the secondary
+input stream as the clean source to pick the fields from. See the filter
+introduction for more details. It is similar to the clip2 feature from
+VFM/TFM.
+
+Default value is 0 (disabled).
+
+- field
+Set the field to match from. It is recommended to set this to the same value as
+order unless you experience matching failures with that setting. In
+certain circumstances changing the field that is used to match from can have a
+large impact on matching performance. Available values are:
+
+
+- ‘auto’
+Automatic (same value as order).
+
- ‘bottom’
+Match from the bottom field.
+
- ‘top’
+Match from the top field.
+
+
+Default value is auto.
+
+- mchroma
+Set whether or not chroma is included during the match comparisons. In most
+cases it is recommended to leave this enabled. You should set this to 0
+only if your clip has bad chroma problems such as heavy rainbowing or other
+artifacts. Setting this to 0 could also be used to speed things up at
+the cost of some accuracy.
+
+Default value is 1.
+
+- y0
+- y1
+These define an exclusion band which excludes the lines between y0 and
+y1 from being included in the field matching decision. An exclusion
+band can be used to ignore subtitles, a logo, or other things that may
+interfere with the matching. y0 sets the starting scan line and
+y1 sets the ending line; all lines in between y0 and
+y1 (including y0 and y1) will be ignored. Setting
+y0 and y1 to the same value will disable the feature.
+y0 and y1 defaults to 0.
+
+- scthresh
+Set the scene change detection threshold as a percentage of maximum change on
+the luma plane. Good values are in the [8.0, 14.0] range. Scene change
+detection is only relevant in case combmatch=sc. The range for
+scthresh is [0.0, 100.0].
+
+Default value is 12.0.
+
+- combmatch
+When combatch is not none, fieldmatch will take into
+account the combed scores of matches when deciding what match to use as the
+final match. Available values are:
+
+
+- ‘none’
+No final matching based on combed scores.
+
- ‘sc’
+Combed scores are only used when a scene change is detected.
+
- ‘full’
+Use combed scores all the time.
+
+
+Default is sc.
+
+- combdbg
+Force fieldmatch to calculate the combed metrics for certain matches and
+print them. This setting is known as micout in TFM/VFM vocabulary.
+Available values are:
+
+
+- ‘none’
+No forced calculation.
+
- ‘pcn’
+Force p/c/n calculations.
+
- ‘pcnub’
+Force p/c/n/u/b calculations.
+
+
+Default value is none.
+
+- cthresh
+This is the area combing threshold used for combed frame detection. This
+essentially controls how "strong" or "visible" combing must be to be detected.
+Larger values mean combing must be more visible and smaller values mean combing
+can be less visible or strong and still be detected. Valid settings are from
+-1 (every pixel will be detected as combed) to 255 (no pixel will
+be detected as combed). This is basically a pixel difference value. A good
+range is [8, 12].
+
+Default value is 9.
+
+- chroma
+Sets whether or not chroma is considered in the combed frame decision. Only
+disable this if your source has chroma problems (rainbowing, etc.) that are
+causing problems for the combed frame detection with chroma enabled. Actually,
+using chroma=0 is usually more reliable, except for the case
+where there is chroma only combing in the source.
+
+Default value is 0.
+
+- blockx
+- blocky
+Respectively set the x-axis and y-axis size of the window used during combed
+frame detection. This has to do with the size of the area in which
+combpel pixels are required to be detected as combed for a frame to be
+declared combed. See the combpel parameter description for more info.
+Possible values are any number that is a power of 2 starting at 4 and going up
+to 512.
+
+Default value is 16.
+
+- combpel
+The number of combed pixels inside any of the blocky by
+blockx size blocks on the frame for the frame to be detected as
+combed. While cthresh controls how "visible" the combing must be, this
+setting controls "how much" combing there must be in any localized area (a
+window defined by the blockx and blocky settings) on the
+frame. Minimum value is 0 and maximum is blocky x blockx (at
+which point no frames will ever be detected as combed). This setting is known
+as MI in TFM/VFM vocabulary.
+
+Default value is 80.
+
+
+
+
+
39.93.1 p/c/n/u/b meaning
+
+
+
+
39.93.1.1 p/c/n
+
+
We assume the following telecined stream:
+
+
+
Top fields: 1 2 2 3 4
+Bottom fields: 1 2 3 4 4
+
+
+
The numbers correspond to the progressive frame the fields relate to. Here, the
+first two frames are progressive, the 3rd and 4th are combed, and so on.
+
+
When fieldmatch is configured to run a matching from bottom
+(field=bottom) this is how this input stream get transformed:
+
+
+
Input stream:
+ T 1 2 2 3 4
+ B 1 2 3 4 4 <-- matching reference
+
+Matches: c c n n c
+
+Output stream:
+ T 1 2 3 4 4
+ B 1 2 3 4 4
+
+
+
As a result of the field matching, we can see that some frames get duplicated.
+To perform a complete inverse telecine, you need to rely on a decimation filter
+after this operation. See for instance the decimate filter.
+
+
The same operation now matching from top fields (field=top)
+looks like this:
+
+
+
Input stream:
+ T 1 2 2 3 4 <-- matching reference
+ B 1 2 3 4 4
+
+Matches: c c p p c
+
+Output stream:
+ T 1 2 2 3 4
+ B 1 2 2 3 4
+
+
+
In these examples, we can see what p, c and n mean;
+basically, they refer to the frame and field of the opposite parity:
+
+
+- p matches the field of the opposite parity in the previous frame
+
- c matches the field of the opposite parity in the current frame
+
- n matches the field of the opposite parity in the next frame
+
+
+
+
+
39.93.1.2 u/b
+
+
The u and b matching are a bit special in the sense that they match
+from the opposite parity flag. In the following examples, we assume that we are
+currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
+’x’ is placed above and below each matched fields.
+
+
With bottom matching (field=bottom):
+
+
Match: c p n b u
+
+ x x x x x
+ Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
+ Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
+ x x x x x
+
+Output frames:
+ 2 1 2 2 2
+ 2 2 2 1 3
+
+
+
With top matching (field=top):
+
+
Match: c p n b u
+
+ x x x x x
+ Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
+ Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
+ x x x x x
+
+Output frames:
+ 2 2 2 1 2
+ 2 1 3 2 2
+
+
+
+
+
+
39.93.2 Examples
+
+
Simple IVTC of a top field first telecined stream:
+
+
fieldmatch=order=tff:combmatch=none, decimate
+
+
+
Advanced IVTC, with fallback on yadif for still combed frames:
+
+
fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
+
+
+
+
+
+
39.94 fieldorder
+
+
Transform the field order of the input video.
+
+
It accepts the following parameters:
+
+
+- order
+The output field order. Valid values are tff for top field first or bff
+for bottom field first.
+
+
+
The default value is ‘tff’.
+
+
The transformation is done by shifting the picture content up or down
+by one line, and filling the remaining line with appropriate picture content.
+This method is consistent with most broadcast field order converters.
+
+
If the input video is not flagged as being interlaced, or it is already
+flagged as being of the required output field order, then this filter does
+not alter the incoming video.
+
+
It is very useful when converting to or from PAL DV material,
+which is bottom field first.
+
+
For example:
+
+
ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
+
+
+
+
+
39.95 fifo, afifo
+
+
Buffer input images and send them when they are requested.
+
+
It is mainly useful when auto-inserted by the libavfilter
+framework.
+
+
It does not take parameters.
+
+
+
+
39.96 fillborders
+
+
Fill borders of the input video, without changing video stream dimensions.
+Sometimes video can have garbage at the four edges and you may not want to
+crop video input to keep size multiple of some number.
+
+
This filter accepts the following options:
+
+
+- left
+Number of pixels to fill from left border.
+
+- right
+Number of pixels to fill from right border.
+
+- top
+Number of pixels to fill from top border.
+
+- bottom
+Number of pixels to fill from bottom border.
+
+- mode
+Set fill mode.
+
+It accepts the following values:
+
+- ‘smear’
+fill pixels using outermost pixels
+
+- ‘mirror’
+fill pixels using mirroring (half sample symmetric)
+
+- ‘fixed’
+fill pixels with constant value
+
+- ‘reflect’
+fill pixels using reflecting (whole sample symmetric)
+
+- ‘wrap’
+fill pixels using wrapping
+
+- ‘fade’
+fade pixels to constant value
+
+- ‘margins’
+fill pixels at top and bottom with weighted averages pixels near borders
+
+
+Default is smear.
+
+- color
+Set color for pixels in fixed or fade mode. Default is black.
+
+
+
+
+
39.96.1 Commands
+
This filter supports same commands as options.
+The command accepts the same syntax of the corresponding option.
+
+
If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
39.97 find_rect
+
+
Find a rectangular object in the input video.
+
+
The object to search for must be specified as a gray8 image specified with the
+object option.
+
+
For each possible match, a score is computed. If the score reaches the specified
+threshold, the object is considered found.
+
+
If the input video contains multiple instances of the object, the filter will
+find only one of them.
+
+
When an object is found, the following metadata entries are set in the matching
+frame:
+
+- lavfi.rect.w
+width of object
+
+- lavfi.rect.h
+height of object
+
+- lavfi.rect.x
+x position of object
+
+- lavfi.rect.y
+y position of object
+
+- lavfi.rect.score
+match score of the found object
+
+
+
It accepts the following options:
+
+
+- object
+Filepath of the object image, needs to be in gray8.
+
+- threshold
+Detection threshold, expressed as a decimal number in the range 0-1.
+
+A threshold value of 0.01 means only exact matches, a threshold of 0.99 means
+almost everything matches.
+
+Default value is 0.5.
+
+- mipmaps
+Number of mipmaps, default is 3.
+
+- xmin, ymin, xmax, ymax
+Specifies the rectangle in which to search.
+
+- discard
+Discard frames where object is not detected. Default is disabled.
+
+
+
+
+
39.97.1 Examples
+
+
+- Cover a rectangular object by the supplied image of a given video using
ffmpeg:
+
+
ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
+
- Find the position of an object in each frame using
ffprobe and write
+it to a log file:
+
+
ffprobe -f lavfi movie=test.mp4,find_rect=object=object.pgm:threshold=0.3 \
+ -show_entries frame=pkt_pts_time:frame_tags=lavfi.rect.x,lavfi.rect.y \
+ -of csv -o find_rect.csv
+
+
+
+
+
+
39.98 floodfill
+
+
Flood area with values of same pixel components with another values.
+
+
It accepts the following options:
+
+- x
+Set pixel x coordinate.
+
+- y
+Set pixel y coordinate.
+
+- s0
+Set source #0 component value.
+
+- s1
+Set source #1 component value.
+
+- s2
+Set source #2 component value.
+
+- s3
+Set source #3 component value.
+
+- d0
+Set destination #0 component value.
+
+- d1
+Set destination #1 component value.
+
+- d2
+Set destination #2 component value.
+
+- d3
+Set destination #3 component value.
+
+
+
+
+
+
39.100 fps
+
+
Convert the video to specified constant frame rate by duplicating or dropping
+frames as necessary.
+
+
It accepts the following parameters:
+
+- fps
+The desired output frame rate. It accepts expressions containing the following
+constants:
+
+
+- ‘source_fps’
+The input’s frame rate
+
+- ‘ntsc’
+NTSC frame rate of 30000/1001
+
+- ‘pal’
+PAL frame rate of 25.0
+
+- ‘film’
+Film frame rate of 24.0
+
+- ‘ntsc_film’
+NTSC-film frame rate of 24000/1001
+
+
+The default is 25.
+
+- start_time
+Assume the first PTS should be the given value, in seconds. This allows for
+padding/trimming at the start of stream. By default, no assumption is made
+about the first frame’s expected PTS, so no padding or trimming is done.
+For example, this could be set to 0 to pad the beginning with duplicates of
+the first frame if a video stream starts after the audio stream or to trim any
+frames with a negative PTS.
+
+- round
+Timestamp (PTS) rounding method.
+
+Possible values are:
+
+- zero
+round towards 0
+
- inf
+round away from 0
+
- down
+round towards -infinity
+
- up
+round towards +infinity
+
- near
+round to nearest
+
+The default is near.
+
+- eof_action
+Action performed when reading the last frame.
+
+Possible values are:
+
+- round
+Use same timestamp rounding method as used for other frames.
+
- pass
+Pass through last frame if input duration has not been reached yet.
+
+The default is round.
+
+
+
+
Alternatively, the options can be specified as a flat string:
+fps[:start_time[:round]].
+
+
See also the setpts filter.
+
+
+
+
39.100.1 Examples
+
+
+- A typical usage in order to set the fps to 25:
+
+
+
- Sets the fps to 24, using abbreviation and rounding method to round to nearest:
+
+
fps=fps=film:round=near
+
+
+
+
+
+
39.101 framepack
+
+
Pack two different video streams into a stereoscopic video, setting proper
+metadata on supported codecs. The two views should have the same size and
+framerate and processing will stop when the shorter video ends. Please note
+that you may conveniently adjust view properties with the scale and
+fps filters.
+
+
It accepts the following parameters:
+
+- format
+The desired packing format. Supported values are:
+
+
+- sbs
+The views are next to each other (default).
+
+- tab
+The views are on top of each other.
+
+- lines
+The views are packed by line.
+
+- columns
+The views are packed by column.
+
+- frameseq
+The views are temporally interleaved.
+
+
+
+
+
+
Some examples:
+
+
+
# Convert left and right views into a frame-sequential video
+ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
+
+# Convert views into a side-by-side video with the same output resolution as the input
+ffmpeg -i LEFT -i RIGHT -filter_complex [0:v]scale=w=iw/2[left],[1:v]scale=w=iw/2[right],[left][right]framepack=sbs OUTPUT
+
+
+
+
+
39.102 framerate
+
+
Change the frame rate by interpolating new video output frames from the source
+frames.
+
+
This filter is not designed to function correctly with interlaced media. If
+you wish to change the frame rate of interlaced media then you are required
+to deinterlace before this filter and re-interlace after this filter.
+
+
A description of the accepted options follows.
+
+
+- fps
+Specify the output frames per second. This option can also be specified
+as a value alone. The default is 50.
+
+- interp_start
+Specify the start of a range where the output frame will be created as a
+linear interpolation of two frames. The range is [0-255],
+the default is 15.
+
+- interp_end
+Specify the end of a range where the output frame will be created as a
+linear interpolation of two frames. The range is [0-255],
+the default is 240.
+
+- scene
+Specify the level at which a scene change is detected as a value between
+0 and 100 to indicate a new scene; a low value reflects a low
+probability for the current frame to introduce a new scene, while a higher
+value means the current frame is more likely to be one.
+The default is 8.2.
+
+- flags
+Specify flags influencing the filter process.
+
+Available value for flags is:
+
+
+- scene_change_detect, scd
+Enable scene change detection using the value of the option scene.
+This flag is enabled by default.
+
+
+
+
+
+
39.103 framestep
+
+
Select one frame every N-th frame.
+
+
This filter accepts the following option:
+
+- step
+Select frame after every step frames.
+Allowed values are positive integers higher than 0. Default value is 1.
+
+
+
+
+
39.104 freezedetect
+
+
Detect frozen video.
+
+
This filter logs a message and sets frame metadata when it detects that the
+input video has no significant change in content during a specified duration.
+Video freeze detection calculates the mean average absolute difference of all
+the components of video frames and compares it to a noise floor.
+
+
The printed times and duration are expressed in seconds. The
+lavfi.freezedetect.freeze_start metadata key is set on the first frame
+whose timestamp equals or exceeds the detection duration and it contains the
+timestamp of the first frame of the freeze. The
+lavfi.freezedetect.freeze_duration and
+lavfi.freezedetect.freeze_end metadata keys are set on the first frame
+after the freeze.
+
+
The filter accepts the following options:
+
+
+- noise, n
+Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
+specified value) or as a difference ratio between 0 and 1. Default is -60dB, or
+0.001.
+
+- duration, d
+Set freeze duration until notification (default is 2 seconds).
+
+
+
+
+
39.105 freezeframes
+
+
Freeze video frames.
+
+
This filter freezes video frames using frame from 2nd input.
+
+
The filter accepts the following options:
+
+
+- first
+Set number of first frame from which to start freeze.
+
+- last
+Set number of last frame from which to end freeze.
+
+- replace
+Set number of frame from 2nd input which will be used instead of replaced frames.
+
+
+
+
+
39.106 frei0r
+
+
Apply a frei0r effect to the input video.
+
+
To enable the compilation of this filter, you need to install the frei0r
+header and configure FFmpeg with --enable-frei0r.
+
+
It accepts the following parameters:
+
+
+- filter_name
+The name of the frei0r effect to load. If the environment variable
+FREI0R_PATH is defined, the frei0r effect is searched for in each of the
+directories specified by the colon-separated list in FREI0R_PATH.
+Otherwise, the standard frei0r paths are searched, in this order:
+HOME/.frei0r-1/lib/, /usr/local/lib/frei0r-1/,
+/usr/lib/frei0r-1/.
+
+- filter_params
+A ’|’-separated list of parameters to pass to the frei0r effect.
+
+
+
+
A frei0r effect parameter can be a boolean (its value is either
+"y" or "n"), a double, a color (specified as
+R/G/B, where R, G, and B are floating point
+numbers between 0.0 and 1.0, inclusive) or a color description as specified in the
+(ffmpeg-utils)"Color" section in the ffmpeg-utils manual,
+a position (specified as X/Y, where
+X and Y are floating point numbers) and/or a string.
+
+
The number and types of parameters depend on the loaded effect. If an
+effect parameter is not specified, the default value is set.
+
+
+
+
39.106.1 Examples
+
+
+- Apply the distort0r effect, setting the first two double parameters:
+
+
frei0r=filter_name=distort0r:filter_params=0.5|0.01
+
- Apply the colordistance effect, taking a color as the first parameter:
+
+
frei0r=colordistance:0.2/0.3/0.4
+frei0r=colordistance:violet
+frei0r=colordistance:0x112233
+
- Apply the perspective effect, specifying the top left and top right image
+positions:
+
+
frei0r=perspective:0.2/0.2|0.8/0.2
+
+
+
For more information, see
+http://frei0r.dyne.org
+
+
+
+
39.106.2 Commands
+
+
This filter supports the filter_params option as commands.
+
+
+
+
+
39.107 fspp
+
+
Apply fast and simple postprocessing. It is a faster version of spp.
+
+
It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
+processing filter, one of them is performed once per block, not per pixel.
+This allows for much higher speed.
+
+
The filter accepts the following options:
+
+
+- quality
+Set quality. This option defines the number of levels for averaging. It accepts
+an integer in the range 4-5. Default value is 4.
+
+- qp
+Force a constant quantization parameter. It accepts an integer in range 0-63.
+If not set, the filter will use the QP from the video stream (if available).
+
+- strength
+Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
+more details but also more artifacts, while higher values make the image smoother
+but also blurrier. Default value is 0 − PSNR optimal.
+
+- use_bframe_qp
+Enable the use of the QP from the B-Frames if set to 1. Using this
+option may cause flicker since the B-Frames have often larger QP. Default is
+0 (not enabled).
+
+
+
+
+
+
39.108 gblur
+
+
Apply Gaussian blur filter.
+
+
The filter accepts the following options:
+
+
+- sigma
+Set horizontal sigma, standard deviation of Gaussian blur. Default is 0.5.
+
+- steps
+Set number of steps for Gaussian approximation. Default is 1.
+
+- planes
+Set which planes to filter. By default all planes are filtered.
+
+- sigmaV
+Set vertical sigma, if negative it will be same as sigma.
+Default is -1.
+
+
+
+
+
39.108.1 Commands
+
This filter supports same commands as options.
+The command accepts the same syntax of the corresponding option.
+
+
If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
39.109 geq
+
+
Apply generic equation to each pixel.
+
+
The filter accepts the following options:
+
+
+- lum_expr, lum
+Set the luminance expression.
+
- cb_expr, cb
+Set the chrominance blue expression.
+
- cr_expr, cr
+Set the chrominance red expression.
+
- alpha_expr, a
+Set the alpha expression.
+
- red_expr, r
+Set the red expression.
+
- green_expr, g
+Set the green expression.
+
- blue_expr, b
+Set the blue expression.
+
+
+
The colorspace is selected according to the specified options. If one
+of the lum_expr, cb_expr, or cr_expr
+options is specified, the filter will automatically select a YCbCr
+colorspace. If one of the red_expr, green_expr, or
+blue_expr options is specified, it will select an RGB
+colorspace.
+
+
If one of the chrominance expression is not defined, it falls back on the other
+one. If no alpha expression is specified it will evaluate to opaque value.
+If none of chrominance expressions are specified, they will evaluate
+to the luminance expression.
+
+
The expressions can use the following variables and functions:
+
+
+- N
+The sequential number of the filtered frame, starting from 0.
+
+- X
+- Y
+The coordinates of the current sample.
+
+- W
+- H
+The width and height of the image.
+
+- SW
+- SH
+Width and height scale depending on the currently filtered plane. It is the
+ratio between the corresponding luma plane number of pixels and the current
+plane ones. E.g. for YUV4:2:0 the values are 1,1 for the luma plane, and
+0.5,0.5 for chroma planes.
+
+- T
+Time of the current frame, expressed in seconds.
+
+- p(x, y)
+Return the value of the pixel at location (x,y) of the current
+plane.
+
+- lum(x, y)
+Return the value of the pixel at location (x,y) of the luminance
+plane.
+
+- cb(x, y)
+Return the value of the pixel at location (x,y) of the
+blue-difference chroma plane. Return 0 if there is no such plane.
+
+- cr(x, y)
+Return the value of the pixel at location (x,y) of the
+red-difference chroma plane. Return 0 if there is no such plane.
+
+- r(x, y)
+- g(x, y)
+- b(x, y)
+Return the value of the pixel at location (x,y) of the
+red/green/blue component. Return 0 if there is no such component.
+
+- alpha(x, y)
+Return the value of the pixel at location (x,y) of the alpha
+plane. Return 0 if there is no such plane.
+
+- psum(x,y), lumsum(x, y), cbsum(x,y), crsum(x,y), rsum(x,y), gsum(x,y), bsum(x,y), alphasum(x,y)
+Sum of sample values in the rectangle from (0,0) to (x,y), this allows obtaining
+sums of samples within a rectangle. See the functions without the sum postfix.
+
+- interpolation
+Set one of interpolation methods:
+
+- nearest, n
+- bilinear, b
+
+Default is bilinear.
+
+
+
For functions, if x and y are outside the area, the value will be
+automatically clipped to the closer edge.
+
+
Please note that this filter can use multiple threads in which case each slice
+will have its own expression state. If you want to use only a single expression
+state because your expressions depend on previous state then you should limit
+the number of filter threads to 1.
+
+
+
+
39.109.1 Examples
+
+
+- Flip the image horizontally:
+
+
+
- Generate a bidimensional sine wave, with angle
PI/3 and a
+wavelength of 100 pixels:
+
+
geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
+
- Generate a fancy enigmatic moving light:
+
+
nullsrc=s=256x256,geq=random(1)/hypot(X-cos(N*0.07)*W/2-W/2\,Y-sin(N*0.09)*H/2-H/2)^2*1000000*sin(N*0.02):128:128
+
- Generate a quick emboss effect:
+
+
format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
+
- Modify RGB components depending on pixel position:
+
+
geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
+
- Create a radial gradient that is the same size as the input (also see
+the vignette filter):
+
+
geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
+
+
+
+
+
+
39.110 gradfun
+
+
Fix the banding artifacts that are sometimes introduced into nearly flat
+regions by truncation to 8-bit color depth.
+Interpolate the gradients that should go where the bands are, and
+dither them.
+
+
It is designed for playback only. Do not use it prior to
+lossy compression, because compression tends to lose the dither and
+bring back the bands.
+
+
It accepts the following parameters:
+
+
+- strength
+The maximum amount by which the filter will change any one pixel. This is also
+the threshold for detecting nearly flat regions. Acceptable values range from
+.51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
+valid range.
+
+- radius
+The neighborhood to fit the gradient to. A larger radius makes for smoother
+gradients, but also prevents the filter from modifying the pixels near detailed
+regions. Acceptable values are 8-32; the default value is 16. Out-of-range
+values will be clipped to the valid range.
+
+
+
+
Alternatively, the options can be specified as a flat string:
+strength[:radius]
+
+
+
+
39.110.1 Examples
+
+
+- Apply the filter with a
3.5 strength and radius of 8:
+
+
+ - Specify radius, omitting the strength (which will fall-back to the default
+value):
+
+
+
+
+
+
+
+
39.111 graphmonitor
+
Show various filtergraph stats.
+
+
With this filter one can debug complete filtergraph.
+Especially issues with links filling with queued frames.
+
+
The filter accepts the following options:
+
+
+- size, s
+Set video output size. Default is hd720.
+
+- opacity, o
+Set video opacity. Default is 0.9. Allowed range is from 0 to 1.
+
+- mode, m
+Set output mode flags.
+
+Available values for flags are:
+
+- ‘full’
+No any filtering. Default.
+
- ‘compact’
+Show only filters with queued frames.
+
- ‘nozero’
+Show only filters with non-zero stats.
+
- ‘noeof’
+Show only filters with non-eof stat.
+
- ‘nodisabled’
+Show only filters that are enabled in timeline.
+
+
+- flags, f
+Set flags which enable which stats are shown in video.
+
+Available values for flags are:
+
+- ‘none’
+All flags turned off.
+
+- ‘all’
+All flags turned on.
+
+- ‘queue’
+Display number of queued frames in each link.
+
+- ‘frame_count_in’
+Display number of frames taken from filter.
+
+- ‘frame_count_out’
+Display number of frames given out from filter.
+
+- ‘frame_count_delta’
+Display delta number of frames between above two values.
+
+- ‘pts’
+Display current filtered frame pts.
+
+- ‘pts_delta’
+Display pts delta between current and previous frame.
+
+- ‘time’
+Display current filtered frame time.
+
+- ‘time_delta’
+Display time delta between current and previous frame.
+
+- ‘timebase’
+Display time base for filter link.
+
+- ‘format’
+Display used format for filter link.
+
+- ‘size’
+Display video size or number of audio channels in case of audio used by filter link.
+
+- ‘rate’
+Display video frame rate or sample rate in case of audio used by filter link.
+
+- ‘eof’
+Display link output status.
+
+- ‘sample_count_in’
+Display number of samples taken from filter.
+
+- ‘sample_count_out’
+Display number of samples given out from filter.
+
+- ‘sample_count_delta’
+Display delta number of samples between above two values.
+
+- ‘disabled’
+Show the timeline filter status.
+
+
+- rate, r
+Set upper limit for video rate of output stream, Default value is 25.
+This guarantee that output video frame rate will not be higher than this value.
+
+
+
+
+
+
39.113 greyedge
+
A color constancy variation filter which estimates scene illumination via grey edge algorithm
+and corrects the scene colors accordingly.
+
+
See: https://staff.science.uva.nl/th.gevers/pub/GeversTIP07.pdf
+
+
The filter accepts the following options:
+
+
+- difford
+The order of differentiation to be applied on the scene. Must be chosen in the range
+[0,2] and default value is 1.
+
+- minknorm
+The Minkowski parameter to be used for calculating the Minkowski distance. Must
+be chosen in the range [0,20] and default value is 1. Set to 0 for getting
+max value instead of calculating Minkowski distance.
+
+- sigma
+The standard deviation of Gaussian blur to be applied on the scene. Must be
+chosen in the range [0,1024.0] and default value = 1. floor( sigma * break_off_sigma(3) )
+can’t be equal to 0 if difford is greater than 0.
+
+
+
+
+
39.113.1 Examples
+
+- Grey Edge:
+
+
greyedge=difford=1:minknorm=5:sigma=2
+
- Max Edge:
+
+
greyedge=difford=1:minknorm=0:sigma=2
+
+
+
+
+
+
39.114 guided
+
Apply guided filter for edge-preserving smoothing, dehazing and so on.
+
+
The filter accepts the following options:
+
+- radius
+Set the box radius in pixels.
+Allowed range is 1 to 20. Default is 3.
+
+- eps
+Set regularization parameter (with square).
+Allowed range is 0 to 1. Default is 0.01.
+
+- mode
+Set filter mode. Can be basic or fast.
+Default is basic.
+
+- sub
+Set subsampling ratio for fast mode.
+Range is 2 to 64. Default is 4.
+No subsampling occurs in basic mode.
+
+- guidance
+Set guidance mode. Can be off or on. Default is off.
+If off, single input is required.
+If on, two inputs of the same resolution and pixel format are required.
+The second input serves as the guidance.
+
+- planes
+Set planes to filter. Default is first only.
+
+
+
+
+
39.114.1 Commands
+
This filter supports the all above options as commands.
+
+
+
+
39.114.2 Examples
+
+- Edge-preserving smoothing with guided filter:
+
+
ffmpeg -i in.png -vf guided out.png
+
- Dehazing, structure-transferring filtering, detail enhancement with guided filter.
+For the generation of guidance image, refer to paper "Guided Image Filtering".
+See: http://kaiminghe.com/publications/pami12guidedfilter.pdf.
+
+
ffmpeg -i in.png -i guidance.png -filter_complex guided=guidance=on out.png
+
+
+
+
+
+
39.115 haldclut
+
+
Apply a Hald CLUT to a video stream.
+
+
First input is the video stream to process, and second one is the Hald CLUT.
+The Hald CLUT input can be a simple picture or a complete video stream.
+
+
The filter accepts the following options:
+
+
+- clut
+Set which CLUT video frames will be processed from second input stream,
+can be first or all. Default is all.
+
+- shortest
+Force termination when the shortest input terminates. Default is 0.
+
- repeatlast
+Continue applying the last CLUT after the end of the stream. A value of
+0 disable the filter after the last frame of the CLUT is reached.
+Default is 1.
+
+
+
haldclut also has the same interpolation options as lut3d (both
+filters share the same internals).
+
+
This filter also supports the framesync options.
+
+
More information about the Hald CLUT can be found on Eskil Steenberg’s website
+(Hald CLUT author) at http://www.quelsolaar.com/technology/clut.html.
+
+
+
+
39.115.1 Commands
+
+
This filter supports the interp option as commands.
+
+
+
+
39.115.2 Workflow examples
+
+
+
+
39.115.2.1 Hald CLUT video stream
+
+
Generate an identity Hald CLUT stream altered with various effects:
+
+
ffmpeg -f lavfi -i haldclutsrc=8 -vf "hue=H=2*PI*t:s=sin(2*PI*t)+1, curves=cross_process" -t 10 -c:v ffv1 clut.nut
+
+
+
Note: make sure you use a lossless codec.
+
+
Then use it with haldclut to apply it on some random stream:
+
+
ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
+
+
+
The Hald CLUT will be applied to the 10 first seconds (duration of
+clut.nut), then the latest picture of that CLUT stream will be applied
+to the remaining frames of the mandelbrot stream.
+
+
+
+
39.115.2.2 Hald CLUT with preview
+
+
A Hald CLUT is supposed to be a squared image of Level*Level*Level by
+Level*Level*Level pixels. For a given Hald CLUT, FFmpeg will select the
+biggest possible square starting at the top left of the picture. The remaining
+padding pixels (bottom or right) will be ignored. This area can be used to add
+a preview of the Hald CLUT.
+
+
Typically, the following generated Hald CLUT will be supported by the
+haldclut filter:
+
+
+
ffmpeg -f lavfi -i haldclutsrc=8 -vf "
+ pad=iw+320 [padded_clut];
+ smptebars=s=320x256, split [a][b];
+ [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
+ [main][b] overlay=W-320" -frames:v 1 clut.png
+
+
+
It contains the original and a preview of the effect of the CLUT: SMPTE color
+bars are displayed on the right-top, and below the same color bars processed by
+the color changes.
+
+
Then, the effect of this Hald CLUT can be visualized with:
+
+
ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
+
+
+
+
+
+
+
39.116 hflip
+
+
Flip the input video horizontally.
+
+
For example, to horizontally flip the input video with ffmpeg:
+
+
ffmpeg -i in.avi -vf "hflip" out.avi
+
+
+
+
+
39.117 histeq
+
This filter applies a global color histogram equalization on a
+per-frame basis.
+
+
It can be used to correct video that has a compressed range of pixel
+intensities. The filter redistributes the pixel intensities to
+equalize their distribution across the intensity range. It may be
+viewed as an "automatically adjusting contrast filter". This filter is
+useful only for correcting degraded or poorly captured source
+video.
+
+
The filter accepts the following options:
+
+
+- strength
+Determine the amount of equalization to be applied. As the strength
+is reduced, the distribution of pixel intensities more-and-more
+approaches that of the input frame. The value must be a float number
+in the range [0,1] and defaults to 0.200.
+
+- intensity
+Set the maximum intensity that can generated and scale the output
+values appropriately. The strength should be set as desired and then
+the intensity can be limited if needed to avoid washing-out. The value
+must be a float number in the range [0,1] and defaults to 0.210.
+
+- antibanding
+Set the antibanding level. If enabled the filter will randomly vary
+the luminance of output pixels by a small amount to avoid banding of
+the histogram. Possible values are none, weak or
+strong. It defaults to none.
+
+
+
+
+
39.118 histogram
+
+
Compute and draw a color distribution histogram for the input video.
+
+
The computed histogram is a representation of the color component
+distribution in an image.
+
+
Standard histogram displays the color components distribution in an image.
+Displays color graph for each color component. Shows distribution of
+the Y, U, V, A or R, G, B components, depending on input format, in the
+current frame. Below each graph a color component scale meter is shown.
+
+
The filter accepts the following options:
+
+
+- level_height
+Set height of level. Default value is 200.
+Allowed range is [50, 2048].
+
+- scale_height
+Set height of color scale. Default value is 12.
+Allowed range is [0, 40].
+
+- display_mode
+Set display mode.
+It accepts the following values:
+
+- ‘stack’
+Per color component graphs are placed below each other.
+
+- ‘parade’
+Per color component graphs are placed side by side.
+
+- ‘overlay’
+Presents information identical to that in the parade, except
+that the graphs representing color components are superimposed directly
+over one another.
+
+Default is stack.
+
+- levels_mode
+Set mode. Can be either linear, or logarithmic.
+Default is linear.
+
+- components
+Set what color components to display.
+Default is 7.
+
+- fgopacity
+Set foreground opacity. Default is 0.7.
+
+- bgopacity
+Set background opacity. Default is 0.5.
+
+- colors_mode
+Set colors mode.
+It accepts the following values:
+
+- ‘whiteonblack’
+- ‘blackonwhite’
+- ‘whiteongray’
+- ‘blackongray’
+- ‘coloronblack’
+- ‘coloronwhite’
+- ‘colorongray’
+- ‘blackoncolor’
+- ‘whiteoncolor’
+- ‘grayoncolor’
+
+Default is whiteonblack.
+
+
+
+
+
39.118.1 Examples
+
+
+- Calculate and draw histogram:
+
+
ffplay -i input -vf histogram
+
+
+
+
+
+
39.119 hqdn3d
+
+
This is a high precision/quality 3d denoise filter. It aims to reduce
+image noise, producing smooth images and making still images really
+still. It should enhance compressibility.
+
+
It accepts the following optional parameters:
+
+
+- luma_spatial
+A non-negative floating point number which specifies spatial luma strength.
+It defaults to 4.0.
+
+- chroma_spatial
+A non-negative floating point number which specifies spatial chroma strength.
+It defaults to 3.0*luma_spatial/4.0.
+
+- luma_tmp
+A floating point number which specifies luma temporal strength. It defaults to
+6.0*luma_spatial/4.0.
+
+- chroma_tmp
+A floating point number which specifies chroma temporal strength. It defaults to
+luma_tmp*chroma_spatial/luma_spatial.
+
+
+
+
+
39.119.1 Commands
+
This filter supports same commands as options.
+The command accepts the same syntax of the corresponding option.
+
+
If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
39.120 hwdownload
+
+
Download hardware frames to system memory.
+
+
The input must be in hardware frames, and the output a non-hardware format.
+Not all formats will be supported on the output - it may be necessary to insert
+an additional format filter immediately following in the graph to get
+the output in a supported format.
+
+
+
+
39.121 hwmap
+
+
Map hardware frames to system memory or to another device.
+
+
This filter has several different modes of operation; which one is used depends
+on the input and output formats:
+
+- Hardware frame input, normal frame output
+
+
Map the input frames to system memory and pass them to the output. If the
+original hardware frame is later required (for example, after overlaying
+something else on part of it), the hwmap filter can be used again
+in the next mode to retrieve it.
+
- Normal frame input, hardware frame output
+
+
If the input is actually a software-mapped hardware frame, then unmap it -
+that is, return the original hardware frame.
+
+Otherwise, a device must be provided. Create new hardware surfaces on that
+device for the output, then map them back to the software format at the input
+and give those frames to the preceding filter. This will then act like the
+hwupload filter, but may be able to avoid an additional copy when
+the input is already in a compatible format.
+
- Hardware frame input and output
+
+
A device must be supplied for the output, either directly or with the
+derive_device option. The input and output devices must be of
+different types and compatible - the exact meaning of this is
+system-dependent, but typically it means that they must refer to the same
+underlying hardware context (for example, refer to the same graphics card).
+
+If the input frames were originally created on the output device, then unmap
+to retrieve the original frames.
+
+Otherwise, map the frames to the output device - create new hardware frames
+on the output corresponding to the frames on the input.
+
+
+
The following additional parameters are accepted:
+
+
+- mode
+Set the frame mapping mode. Some combination of:
+
+- read
+The mapped frame should be readable.
+
- write
+The mapped frame should be writeable.
+
- overwrite
+The mapping will always overwrite the entire frame.
+
+This may improve performance in some cases, as the original contents of the
+frame need not be loaded.
+
- direct
+The mapping must not involve any copying.
+
+Indirect mappings to copies of frames are created in some cases where either
+direct mapping is not possible or it would have unexpected properties.
+Setting this flag ensures that the mapping is direct and will fail if that is
+not possible.
+
+Defaults to read+write if not specified.
+
+- derive_device type
+Rather than using the device supplied at initialisation, instead derive a new
+device of type type from the device the input frames exist on.
+
+- reverse
+In a hardware to hardware mapping, map in reverse - create frames in the sink
+and map them back to the source. This may be necessary in some cases where
+a mapping in one direction is required but only the opposite direction is
+supported by the devices being used.
+
+This option is dangerous - it may break the preceding filter in undefined
+ways if there are any additional constraints on that filter’s output.
+Do not use it without fully understanding the implications of its use.
+
+
+
+
+
39.122 hwupload
+
+
Upload system memory frames to hardware surfaces.
+
+
The device to upload to must be supplied when the filter is initialised. If
+using ffmpeg, select the appropriate device with the -filter_hw_device
+option or with the derive_device option. The input and output devices
+must be of different types and compatible - the exact meaning of this is
+system-dependent, but typically it means that they must refer to the same
+underlying hardware context (for example, refer to the same graphics card).
+
+
The following additional parameters are accepted:
+
+
+- derive_device type
+Rather than using the device supplied at initialisation, instead derive a new
+device of type type from the device the input frames exist on.
+
+
+
+
+
39.123 hwupload_cuda
+
+
Upload system memory frames to a CUDA device.
+
+
It accepts the following optional parameters:
+
+
+- device
+The number of the CUDA device to use
+
+
+
+
+
39.124 hqx
+
+
Apply a high-quality magnification filter designed for pixel art. This filter
+was originally created by Maxim Stepin.
+
+
It accepts the following option:
+
+
+- n
+Set the scaling dimension: 2 for hq2x, 3 for
+hq3x and 4 for hq4x.
+Default is 3.
+
+
+
+
+
39.125 hstack
+
Stack input videos horizontally.
+
+
All streams must be of same pixel format and of same height.
+
+
Note that this filter is faster than using overlay and pad filter
+to create same output.
+
+
The filter accepts the following option:
+
+
+- inputs
+Set number of input streams. Default is 2.
+
+- shortest
+If set to 1, force the output to terminate when the shortest input
+terminates. Default value is 0.
+
+
+
+
+
39.126 hsvhold
+
Turns a certain HSV range into gray values.
+
+
This filter measures color difference between set HSV color in options
+and ones measured in video stream. Depending on options, output
+colors can be changed to be gray or not.
+
+
The filter accepts the following options:
+
+
+- hue
+Set the hue value which will be used in color difference calculation.
+Allowed range is from -360 to 360. Default value is 0.
+
+- sat
+Set the saturation value which will be used in color difference calculation.
+Allowed range is from -1 to 1. Default value is 0.
+
+- val
+Set the value which will be used in color difference calculation.
+Allowed range is from -1 to 1. Default value is 0.
+
+- similarity
+Set similarity percentage with the key color.
+Allowed range is from 0 to 1. Default value is 0.01.
+
+0.00001 matches only the exact key color, while 1.0 matches everything.
+
+- blend
+Blend percentage.
+Allowed range is from 0 to 1. Default value is 0.
+
+0.0 makes pixels either fully gray, or not gray at all.
+
+Higher values result in more gray pixels, with a higher gray pixel
+the more similar the pixels color is to the key color.
+
+
+
+
+
39.127 hsvkey
+
Turns a certain HSV range into transparency.
+
+
This filter measures color difference between set HSV color in options
+and ones measured in video stream. Depending on options, output
+colors can be changed to transparent by adding alpha channel.
+
+
The filter accepts the following options:
+
+
+- hue
+Set the hue value which will be used in color difference calculation.
+Allowed range is from -360 to 360. Default value is 0.
+
+- sat
+Set the saturation value which will be used in color difference calculation.
+Allowed range is from -1 to 1. Default value is 0.
+
+- val
+Set the value which will be used in color difference calculation.
+Allowed range is from -1 to 1. Default value is 0.
+
+- similarity
+Set similarity percentage with the key color.
+Allowed range is from 0 to 1. Default value is 0.01.
+
+0.00001 matches only the exact key color, while 1.0 matches everything.
+
+- blend
+Blend percentage.
+Allowed range is from 0 to 1. Default value is 0.
+
+0.0 makes pixels either fully transparent, or not transparent at all.
+
+Higher values result in semi-transparent pixels, with a higher transparency
+the more similar the pixels color is to the key color.
+
+
+
+
+
39.128 hue
+
+
Modify the hue and/or the saturation of the input.
+
+
It accepts the following parameters:
+
+
+- h
+Specify the hue angle as a number of degrees. It accepts an expression,
+and defaults to "0".
+
+- s
+Specify the saturation in the [-10,10] range. It accepts an expression and
+defaults to "1".
+
+- H
+Specify the hue angle as a number of radians. It accepts an
+expression, and defaults to "0".
+
+- b
+Specify the brightness in the [-10,10] range. It accepts an expression and
+defaults to "0".
+
+
+
h and H are mutually exclusive, and can’t be
+specified at the same time.
+
+
The b, h, H and s option values are
+expressions containing the following constants:
+
+
+- n
+frame count of the input frame starting from 0
+
+- pts
+presentation timestamp of the input frame expressed in time base units
+
+- r
+frame rate of the input video, NAN if the input frame rate is unknown
+
+- t
+timestamp expressed in seconds, NAN if the input timestamp is unknown
+
+- tb
+time base of the input video
+
+
+
+
+
39.128.1 Examples
+
+
+
+
+
+
39.128.2 Commands
+
+
This filter supports the following commands:
+
+- b
+- s
+- h
+- H
+Modify the hue and/or the saturation and/or brightness of the input video.
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
+
39.129 huesaturation
+
Apply hue-saturation-intensity adjustments to input video stream.
+
+
This filter operates in RGB colorspace.
+
+
This filter accepts the following options:
+
+
+- hue
+Set the hue shift in degrees to apply. Default is 0.
+Allowed range is from -180 to 180.
+
+- saturation
+Set the saturation shift. Default is 0.
+Allowed range is from -1 to 1.
+
+- intensity
+Set the intensity shift. Default is 0.
+Allowed range is from -1 to 1.
+
+- colors
+Set which primary and complementary colors are going to be adjusted.
+This options is set by providing one or multiple values.
+This can select multiple colors at once. By default all colors are selected.
+
+- ‘r’
+Adjust reds.
+
- ‘y’
+Adjust yellows.
+
- ‘g’
+Adjust greens.
+
- ‘c’
+Adjust cyans.
+
- ‘b’
+Adjust blues.
+
- ‘m’
+Adjust magentas.
+
- ‘a’
+Adjust all colors.
+
+
+- strength
+Set strength of filtering. Allowed range is from 0 to 100.
+Default value is 1.
+
+- rw, gw, bw
+Set weight for each RGB component. Allowed range is from 0 to 1.
+By default is set to 0.333, 0.334, 0.333.
+Those options are used in saturation and lightess processing.
+
+- lightness
+Set preserving lightness, by default is disabled.
+Adjusting hues can change lightness from original RGB triplet,
+with this option enabled lightness is kept at same value.
+
+
+
+
+
39.130 hysteresis
+
+
Grow first stream into second stream by connecting components.
+This makes it possible to build more robust edge masks.
+
+
This filter accepts the following options:
+
+
+- planes
+Set which planes will be processed as bitmap, unprocessed planes will be
+copied from first stream.
+By default value 0xf, all planes will be processed.
+
+- threshold
+Set threshold which is used in filtering. If pixel component value is higher than
+this value filter algorithm for connecting components is activated.
+By default value is 0.
+
+
+
The hysteresis filter also supports the framesync options.
+
+
+
+
39.131 iccdetect
+
+
Detect the colorspace from an embedded ICC profile (if present), and update
+the frame’s tags accordingly.
+
+
This filter accepts the following options:
+
+
+- force
+If true, the frame’s existing colorspace tags will always be overridden by
+values detected from an ICC profile. Otherwise, they will only be assigned if
+they contain unknown. Enabled by default.
+
+
+
+
+
39.132 iccgen
+
+
Generate ICC profiles and attach them to frames.
+
+
This filter accepts the following options:
+
+
+- color_primaries
+- color_trc
+Configure the colorspace that the ICC profile will be generated for. The
+default value of auto infers the value from the input frame’s metadata,
+defaulting to BT.709/sRGB as appropriate.
+
+See the setparams filter for a list of possible values, but note that
+unknown are not valid values for this filter.
+
+- force
+If true, an ICC profile will be generated even if it would overwrite an
+already existing ICC profile. Disabled by default.
+
+
+
+
+
39.133 identity
+
+
Obtain the identity score between two input videos.
+
+
This filter takes two input videos.
+
+
Both input videos must have the same resolution and pixel format for
+this filter to work correctly. Also it assumes that both inputs
+have the same number of frames, which are compared one by one.
+
+
The obtained per component, average, min and max identity score is printed through
+the logging system.
+
+
The filter stores the calculated identity scores of each frame in frame metadata.
+
+
This filter also supports the framesync options.
+
+
In the below example the input file main.mpg being processed is compared
+with the reference file ref.mpg.
+
+
+
ffmpeg -i main.mpg -i ref.mpg -lavfi identity -f null -
+
+
+
+
+
39.134 idet
+
+
Detect video interlacing type.
+
+
This filter tries to detect if the input frames are interlaced, progressive,
+top or bottom field first. It will also try to detect fields that are
+repeated between adjacent frames (a sign of telecine).
+
+
Single frame detection considers only immediately adjacent frames when classifying each frame.
+Multiple frame detection incorporates the classification history of previous frames.
+
+
The filter will log these metadata values:
+
+
+- single.current_frame
+Detected type of current frame using single-frame detection. One of:
+“tff” (top field first), “bff” (bottom field first),
+“progressive”, or “undetermined”
+
+- single.tff
+Cumulative number of frames detected as top field first using single-frame detection.
+
+- multiple.tff
+Cumulative number of frames detected as top field first using multiple-frame detection.
+
+- single.bff
+Cumulative number of frames detected as bottom field first using single-frame detection.
+
+- multiple.current_frame
+Detected type of current frame using multiple-frame detection. One of:
+“tff” (top field first), “bff” (bottom field first),
+“progressive”, or “undetermined”
+
+- multiple.bff
+Cumulative number of frames detected as bottom field first using multiple-frame detection.
+
+- single.progressive
+Cumulative number of frames detected as progressive using single-frame detection.
+
+- multiple.progressive
+Cumulative number of frames detected as progressive using multiple-frame detection.
+
+- single.undetermined
+Cumulative number of frames that could not be classified using single-frame detection.
+
+- multiple.undetermined
+Cumulative number of frames that could not be classified using multiple-frame detection.
+
+- repeated.current_frame
+Which field in the current frame is repeated from the last. One of “neither”, “top”, or “bottom”.
+
+- repeated.neither
+Cumulative number of frames with no repeated field.
+
+- repeated.top
+Cumulative number of frames with the top field repeated from the previous frame’s top field.
+
+- repeated.bottom
+Cumulative number of frames with the bottom field repeated from the previous frame’s bottom field.
+
+
+
The filter accepts the following options:
+
+
+- intl_thres
+Set interlacing threshold.
+
- prog_thres
+Set progressive threshold.
+
- rep_thres
+Threshold for repeated field detection.
+
- half_life
+Number of frames after which a given frame’s contribution to the
+statistics is halved (i.e., it contributes only 0.5 to its
+classification). The default of 0 means that all frames seen are given
+full weight of 1.0 forever.
+
- analyze_interlaced_flag
+When this is not 0 then idet will use the specified number of frames to determine
+if the interlaced flag is accurate, it will not count undetermined frames.
+If the flag is found to be accurate it will be used without any further
+computations, if it is found to be inaccurate it will be cleared without any
+further computations. This allows inserting the idet filter as a low computational
+method to clean up the interlaced flag
+
+
+
+
+
39.135 il
+
+
Deinterleave or interleave fields.
+
+
This filter allows one to process interlaced images fields without
+deinterlacing them. Deinterleaving splits the input frame into 2
+fields (so called half pictures). Odd lines are moved to the top
+half of the output image, even lines to the bottom half.
+You can process (filter) them independently and then re-interleave them.
+
+
The filter accepts the following options:
+
+
+- luma_mode, l
+- chroma_mode, c
+- alpha_mode, a
+Available values for luma_mode, chroma_mode and
+alpha_mode are:
+
+
+- ‘none’
+Do nothing.
+
+- ‘deinterleave, d’
+Deinterleave fields, placing one above the other.
+
+- ‘interleave, i’
+Interleave fields. Reverse the effect of deinterleaving.
+
+Default value is none.
+
+- luma_swap, ls
+- chroma_swap, cs
+- alpha_swap, as
+Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is 0.
+
+
+
+
+
39.135.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.136 inflate
+
+
Apply inflate effect to the video.
+
+
This filter replaces the pixel by the local(3x3) average by taking into account
+only values higher than the pixel.
+
+
It accepts the following options:
+
+
+- threshold0
+- threshold1
+- threshold2
+- threshold3
+Limit the maximum change for each plane, default is 65535.
+If 0, plane will remain unchanged.
+
+
+
+
+
39.136.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.137 interlace
+
+
Simple interlacing filter from progressive contents. This interleaves upper (or
+lower) lines from odd frames with lower (or upper) lines from even frames,
+halving the frame rate and preserving image height.
+
+
+
Original Original New Frame
+ Frame 'j' Frame 'j+1' (tff)
+ ========== =========== ==================
+ Line 0 --------------------> Frame 'j' Line 0
+ Line 1 Line 1 ----> Frame 'j+1' Line 1
+ Line 2 ---------------------> Frame 'j' Line 2
+ Line 3 Line 3 ----> Frame 'j+1' Line 3
+ ... ... ...
+New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
+
+
+
It accepts the following optional parameters:
+
+
+- scan
+This determines whether the interlaced frame is taken from the even
+(tff - default) or odd (bff) lines of the progressive frame.
+
+- lowpass
+Vertical lowpass filter to avoid twitter interlacing and
+reduce moire patterns.
+
+
+- ‘0, off’
+Disable vertical lowpass filter
+
+- ‘1, linear’
+Enable linear filter (default)
+
+- ‘2, complex’
+Enable complex filter. This will slightly less reduce twitter and moire
+but better retain detail and subjective sharpness impression.
+
+
+
+
+
+
+
39.138 kerndeint
+
+
Deinterlace input video by applying Donald Graft’s adaptive kernel
+deinterling. Work on interlaced parts of a video to produce
+progressive frames.
+
+
The description of the accepted parameters follows.
+
+
+- thresh
+Set the threshold which affects the filter’s tolerance when
+determining if a pixel line must be processed. It must be an integer
+in the range [0,255] and defaults to 10. A value of 0 will result in
+applying the process on every pixels.
+
+- map
+Paint pixels exceeding the threshold value to white if set to 1.
+Default is 0.
+
+- order
+Set the fields order. Swap fields if set to 1, leave fields alone if
+0. Default is 0.
+
+- sharp
+Enable additional sharpening if set to 1. Default is 0.
+
+- twoway
+Enable twoway sharpening if set to 1. Default is 0.
+
+
+
+
+
39.138.1 Examples
+
+
+- Apply default values:
+
+
kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
+
- Enable additional sharpening:
+
+
+
- Paint processed pixels in white:
+
+
+
+
+
+
+
39.139 kirsch
+
Apply kirsch operator to input video stream.
+
+
The filter accepts the following option:
+
+
+- planes
+Set which planes will be processed, unprocessed planes will be copied.
+By default value 0xf, all planes will be processed.
+
+- scale
+Set value which will be multiplied with filtered result.
+
+- delta
+Set value which will be added to filtered result.
+
+
+
+
+
39.139.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.140 lagfun
+
+
Slowly update darker pixels.
+
+
This filter makes short flashes of light appear longer.
+This filter accepts the following options:
+
+
+- decay
+Set factor for decaying. Default is .95. Allowed range is from 0 to 1.
+
+- planes
+Set which planes to filter. Default is all. Allowed range is from 0 to 15.
+
+
+
+
+
39.140.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.141 lenscorrection
+
+
Correct radial lens distortion
+
+
This filter can be used to correct for radial distortion as can result from the use
+of wide angle lenses, and thereby re-rectify the image. To find the right parameters
+one can use tools available for example as part of opencv or simply trial-and-error.
+To use opencv use the calibration sample (under samples/cpp) from the opencv sources
+and extract the k1 and k2 coefficients from the resulting matrix.
+
+
Note that effectively the same filter is available in the open-source tools Krita and
+Digikam from the KDE project.
+
+
In contrast to the vignette filter, which can also be used to compensate lens errors,
+this filter corrects the distortion of the image, whereas vignette corrects the
+brightness distribution, so you may want to use both filters together in certain
+cases, though you will have to take care of ordering, i.e. whether vignetting should
+be applied before or after lens correction.
+
+
+
+
39.141.1 Options
+
+
The filter accepts the following options:
+
+
+- cx
+Relative x-coordinate of the focal point of the image, and thereby the center of the
+distortion. This value has a range [0,1] and is expressed as fractions of the image
+width. Default is 0.5.
+
- cy
+Relative y-coordinate of the focal point of the image, and thereby the center of the
+distortion. This value has a range [0,1] and is expressed as fractions of the image
+height. Default is 0.5.
+
- k1
+Coefficient of the quadratic correction term. This value has a range [-1,1]. 0 means
+no correction. Default is 0.
+
- k2
+Coefficient of the double quadratic correction term. This value has a range [-1,1].
+0 means no correction. Default is 0.
+
- i
+Set interpolation type. Can be nearest or bilinear.
+Default is nearest.
+
- fc
+Specify the color of the unmapped pixels. For the syntax of this option,
+check the (ffmpeg-utils)"Color" section in the ffmpeg-utils
+manual. Default color is black@0.
+
+
+
The formula that generates the correction is:
+
+
r_src = r_tgt * (1 + k1 * (r_tgt / r_0)^2 + k2 * (r_tgt / r_0)^4)
+
+
where r_0 is halve of the image diagonal and r_src and r_tgt are the
+distances from the focal point in the source and target images, respectively.
+
+
+
+
39.141.2 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.142 lensfun
+
+
Apply lens correction via the lensfun library (http://lensfun.sourceforge.net/).
+
+
The lensfun filter requires the camera make, camera model, and lens model
+to apply the lens correction. The filter will load the lensfun database and
+query it to find the corresponding camera and lens entries in the database. As
+long as these entries can be found with the given options, the filter can
+perform corrections on frames. Note that incomplete strings will result in the
+filter choosing the best match with the given options, and the filter will
+output the chosen camera and lens models (logged with level "info"). You must
+provide the make, camera model, and lens model as they are required.
+
+
To obtain a list of available makes and models, leave out one or both of make and
+model options. The filter will send the full list to the log with level INFO.
+The first column is the make and the second column is the model.
+To obtain a list of available lenses, set any values for make and model and leave out the
+lens_model option. The filter will send the full list of lenses in the log with level
+INFO. The ffmpeg tool will exit after the list is printed.
+
+
The filter accepts the following options:
+
+
+- make
+The make of the camera (for example, "Canon"). This option is required.
+
+- model
+The model of the camera (for example, "Canon EOS 100D"). This option is
+required.
+
+- lens_model
+The model of the lens (for example, "Canon EF-S 18-55mm f/3.5-5.6 IS STM"). This
+option is required.
+
+- db_path
+The full path to the lens database folder. If not set, the filter will attempt to
+load the database from the install path when the library was built. Default is unset.
+
+- mode
+The type of correction to apply. The following values are valid options:
+
+
+- ‘vignetting’
+Enables fixing lens vignetting.
+
+- ‘geometry’
+Enables fixing lens geometry. This is the default.
+
+- ‘subpixel’
+Enables fixing chromatic aberrations.
+
+- ‘vig_geo’
+Enables fixing lens vignetting and lens geometry.
+
+- ‘vig_subpixel’
+Enables fixing lens vignetting and chromatic aberrations.
+
+- ‘distortion’
+Enables fixing both lens geometry and chromatic aberrations.
+
+- ‘all’
+Enables all possible corrections.
+
+
+- focal_length
+The focal length of the image/video (zoom; expected constant for video). For
+example, a 18–55mm lens has focal length range of [18–55], so a value in that
+range should be chosen when using that lens. Default 18.
+
+- aperture
+The aperture of the image/video (expected constant for video). Note that
+aperture is only used for vignetting correction. Default 3.5.
+
+- focus_distance
+The focus distance of the image/video (expected constant for video). Note that
+focus distance is only used for vignetting and only slightly affects the
+vignetting correction process. If unknown, leave it at the default value (which
+is 1000).
+
+- scale
+The scale factor which is applied after transformation. After correction the
+video is no longer necessarily rectangular. This parameter controls how much of
+the resulting image is visible. The value 0 means that a value will be chosen
+automatically such that there is little or no unmapped area in the output
+image. 1.0 means that no additional scaling is done. Lower values may result
+in more of the corrected image being visible, while higher values may avoid
+unmapped areas in the output.
+
+- target_geometry
+The target geometry of the output image/video. The following values are valid
+options:
+
+
+- ‘rectilinear (default)’
+- ‘fisheye’
+- ‘panoramic’
+- ‘equirectangular’
+- ‘fisheye_orthographic’
+- ‘fisheye_stereographic’
+- ‘fisheye_equisolid’
+- ‘fisheye_thoby’
+
+- reverse
+Apply the reverse of image correction (instead of correcting distortion, apply
+it).
+
+- interpolation
+The type of interpolation used when correcting distortion. The following values
+are valid options:
+
+
+- ‘nearest’
+- ‘linear (default)’
+- ‘lanczos’
+
+
+
+
+
+
39.142.1 Examples
+
+
+- Apply lens correction with make "Canon", camera model "Canon EOS 100D", and lens
+model "Canon EF-S 18-55mm f/3.5-5.6 IS STM" with focal length of "18" and
+aperture of "8.0".
+
+
+
ffmpeg -i input.mov -vf lensfun=make=Canon:model="Canon EOS 100D":lens_model="Canon EF-S 18-55mm f/3.5-5.6 IS STM":focal_length=18:aperture=8 -c:v h264 -b:v 8000k output.mov
+
- Apply the same as before, but only for the first 5 seconds of video.
+
+
+
ffmpeg -i input.mov -vf lensfun=make=Canon:model="Canon EOS 100D":lens_model="Canon EF-S 18-55mm f/3.5-5.6 IS STM":focal_length=18:aperture=8:enable='lte(t\,5)' -c:v h264 -b:v 8000k output.mov
+
+
+
+
+
+
39.143 libplacebo
+
+
Flexible GPU-accelerated processing filter based on libplacebo
+(https://code.videolan.org/videolan/libplacebo).
+
+
+
+
39.143.1 Options
+
+
The options for this filter are divided into the following sections:
+
+
+
+
39.143.1.1 Output mode
+
These options control the overall output mode. By default, libplacebo will try
+to preserve the source colorimetry and size as best as it can, but it will
+apply any embedded film grain, dolby vision metadata or anamorphic SAR present
+in source frames.
+
+- w
+- h
+Set the output video dimension expression. Default values are iw and
+ih.
+
+Allows for the same expressions as the scale filter.
+
+- crop_x
+- crop_y
+Set the input crop x/y expressions, default values are (iw-cw)/2 and
+(ih-ch)/2.
+
+- crop_w
+- crop_h
+Set the input crop width/height expressions, default values are iw and
+ih.
+
+- pos_x
+- pos_y
+Set the output placement x/y expressions, default values are (ow-pw)/2
+and (oh-ph)/2.
+
+- pos_w
+- pos_h
+Set the output placement width/height expressions, default values are ow
+and oh.
+
+- fps
+Set the output frame rate. This can be rational, e.g. 60000/1001. If
+set to the special string none (the default), input timestamps will
+instead be passed through to the output unmodified. Otherwise, the input video
+frames will be interpolated as necessary to rescale the video to the specified
+target framerate, in a manner as determined by the frame_mixer option.
+
+- format
+Set the output format override. If unset (the default), frames will be output
+in the same format as the respective input frames. Otherwise, format conversion
+will be performed.
+
+- force_original_aspect_ratio
+- force_divisible_by
+Work the same as the identical scale filter options.
+
+- normalize_sar
+If enabled, output frames will always have a pixel aspect ratio of 1:1. This
+will introduce additional padding/cropping as necessary. If disabled (the
+default), any aspect ratio mismatches, including those from e.g. anamorphic
+video sources, are forwarded to the output pixel aspect ratio.
+
+- pad_crop_ratio
+Specifies a ratio (between 0.0 and 1.0) between padding and
+cropping when the input aspect ratio does not match the output aspect ratio and
+normalize_sar is in effect. The default of 0.0 always pads the
+content with black borders, while a value of 1.0 always crops off parts
+of the content. Intermediate values are possible, leading to a mix of the two
+approaches.
+
+- fillcolor
+Set the color used to fill the output area not covered by the output image, for
+example as a result of normalize_sar. For the general syntax of this
+option, check the (ffmpeg-utils)"Color" section in the ffmpeg-utils
+manual. Defaults to black.
+
+- colorspace
+- color_primaries
+- color_trc
+- range
+Configure the colorspace that output frames will be delivered in. The default
+value of auto outputs frames in the same format as the input frames,
+leading to no change. For any other value, conversion will be performed.
+
+See the setparams filter for a list of possible values.
+
+- apply_filmgrain
+Apply film grain (e.g. AV1 or H.274) if present in source frames, and strip
+it from the output. Enabled by default.
+
+- apply_dolbyvision
+Apply Dolby Vision RPU metadata if present in source frames, and strip it from
+the output. Enabled by default. Note that Dolby Vision will always output
+BT.2020+PQ, overriding the usual input frame metadata. These will also be
+picked as the values of auto for the respective frame output options.
+
+
+
In addition to the expression constants documented for the scale filter,
+the crop_w, crop_h, crop_x, crop_y,
+pos_w, pos_h, pos_x and pos_y options can
+also contain the following constants:
+
+
+- crop_w, cw
+- crop_h, ch
+The computed values of crop_w and crop_h.
+
+- pos_w, pw
+- pos_h, ph
+The computed values of pos_w and pos_h.
+
+- in_t, t
+The input frame timestamp, in seconds. NAN if input timestamp is unknown.
+
+- out_t, ot
+The input frame timestamp, in seconds. NAN if input timestamp is unknown.
+
+- n
+The input frame number, starting with 0.
+
+
+
+
+
39.143.1.2 Scaling
+
The options in this section control how libplacebo performs upscaling and (if
+necessary) downscaling. Note that libplacebo will always internally operate on
+4:4:4 content, so any sub-sampled chroma formats such as yuv420p will
+necessarily be upsampled and downsampled as part of the rendering process. That
+means scaling might be in effect even if the source and destination resolution
+are the same.
+
+- upscaler
+- downscaler
+Configure the filter kernel used for upscaling and downscaling. The respective
+defaults are spline36 and mitchell. For a full list of possible
+values, pass help to these options. The most important values are:
+
+- ‘none’
+Forces the use of built-in GPU texture sampling (typically bilinear). Extremely
+fast but poor quality, especially when downscaling.
+
+- ‘bilinear’
+Bilinear interpolation. Can generally be done for free on GPUs, except when
+doing so would lead to aliasing. Fast and low quality.
+
+- ‘nearest’
+Nearest-neighbour interpolation. Sharp but highly aliasing.
+
+- ‘oversample’
+Algorithm that looks visually similar to nearest-neighbour interpolation but
+tries to preserve pixel aspect ratio. Good for pixel art, since it results in
+minimal distortion of the artistic appearance.
+
+- ‘lanczos’
+Standard sinc-sinc interpolation kernel.
+
+- ‘spline36’
+Cubic spline approximation of lanczos. No difference in performance, but has
+very slightly less ringing.
+
+- ‘ewa_lanczos’
+Elliptically weighted average version of lanczos, based on a jinc-sinc kernel.
+This is also popularly referred to as just "Jinc scaling". Slow but very high
+quality.
+
+- ‘gaussian’
+Gaussian kernel. Has certain ideal mathematical properties, but subjectively
+very blurry.
+
+- ‘mitchell’
+Cubic BC spline with parameters recommended by Mitchell and Netravali. Very
+little ringing.
+
+
+- frame_mixer
+Controls the kernel used for mixing frames temporally. The default value is
+none, which disables frame mixing. For a full list of possible values,
+pass help to this option. The most important values are:
+
+- ‘none’
+Disables frame mixing, giving a result equivalent to "nearest neighbour"
+semantics.
+
+- ‘oversample’
+Oversamples the input video to create a "Smooth Motion"-type effect: if an
+output frame would exactly fall on the transition between two video frames, it
+is blended according to the relative overlap. This is the recommended option
+whenever preserving the original subjective appearance is desired.
+
+- ‘mitchell_clamp’
+Larger filter kernel that smoothly interpolates multiple frames in a manner
+designed to eliminate ringing and other artefacts as much as possible. This is
+the recommended option wherever maximum visual smoothness is desired.
+
+- ‘linear’
+Linear blend/fade between frames. Especially useful for constructing e.g.
+slideshows.
+
+
+- lut_entries
+Configures the size of scaler LUTs, ranging from 1 to 256. The
+default of 0 will pick libplacebo’s internal default, typically
+64.
+
+- antiringing
+Enables anti-ringing (for non-EWA filters). The value (between 0.0 and
+1.0) configures the strength of the anti-ringing algorithm. May increase
+aliasing if set too high. Disabled by default.
+
+- sigmoid
+Enable sigmoidal compression during upscaling. Reduces ringing slightly.
+Enabled by default.
+
+
+
+
+
39.143.1.3 Debanding
+
Libplacebo comes with a built-in debanding filter that is good at counteracting
+many common sources of banding and blocking. Turning this on is highly
+recommended whenever quality is desired.
+
+- deband
+Enable (fast) debanding algorithm. Disabled by default.
+
+- deband_iterations
+Number of deband iterations of the debanding algorithm. Each iteration is
+performed with progressively increased radius (and diminished threshold).
+Recommended values are in the range 1 to 4. Defaults to 1.
+
+- deband_threshold
+Debanding filter strength. Higher numbers lead to more aggressive debanding.
+Defaults to 4.0.
+
+- deband_radius
+Debanding filter radius. A higher radius is better for slow gradients, while
+a lower radius is better for steep gradients. Defaults to 16.0.
+
+- deband_grain
+Amount of extra output grain to add. Helps hide imperfections. Defaults to
+6.0.
+
+
+
+
+
39.143.1.4 Color adjustment
+
A collection of subjective color controls. Not very rigorous, so the exact
+effect will vary somewhat depending on the input primaries and colorspace.
+
+- brightness
+Brightness boost, between -1.0 and 1.0. Defaults to 0.0.
+
+- contrast
+Contrast gain, between 0.0 and 16.0. Defaults to 1.0.
+
+- saturation
+Saturation gain, between 0.0 and 16.0. Defaults to 1.0.
+
+- hue
+Hue shift in radians, between -3.14 and 3.14. Defaults to
+0.0. This will rotate the UV subvector, defaulting to BT.709
+coefficients for RGB inputs.
+
+- gamma
+Gamma adjustment, between 0.0 and 16.0. Defaults to 1.0.
+
+- cones
+Cone model to use for color blindness simulation. Accepts any combination of
+l, m and s. Here are some examples:
+
+- ‘m’
+Deuteranomaly / deuteranopia (affecting 3%-4% of the population)
+
- ‘l’
+Protanomaly / protanopia (affecting 1%-2% of the population)
+
- ‘l+m’
+Monochromacy (very rare)
+
- ‘l+m+s’
+Achromatopsy (complete loss of daytime vision, extremely rare)
+
+
+- cone-strength
+Gain factor for the cones specified by cones, between 0.0 and
+10.0. A value of 1.0 results in no change to color vision. A
+value of 0.0 (the default) simulates complete loss of those cones. Values
+above 1.0 result in exaggerating the differences between cones, which
+may help compensate for reduced color vision.
+
+
+
+
+
39.143.1.5 Peak detection
+
To help deal with sources that only have static HDR10 metadata (or no tagging
+whatsoever), libplacebo uses its own internal frame analysis compute shader to
+analyze source frames and adapt the tone mapping function in realtime. If this
+is too slow, or if exactly reproducible frame-perfect results are needed, it’s
+recommended to turn this feature off.
+
+- peak_detect
+Enable HDR peak detection. Ignores static MaxCLL/MaxFALL values in favor of
+dynamic detection from the input. Note that the detected values do not get
+written back to the output frames, they merely guide the internal tone mapping
+process. Enabled by default.
+
+- smoothing_period
+Peak detection smoothing period, between 0.0 and 1000.0. Higher
+values result in peak detection becoming less responsive to changes in the
+input. Defaults to 100.0.
+
+- minimum_peak
+Lower bound on the detected peak (relative to SDR white), between 0.0
+and 100.0. Defaults to 1.0.
+
+- scene_threshold_low
+- scene_threshold_high
+Lower and upper thresholds for scene change detection. Expressed in a
+logarithmic scale between 0.0 and 100.0. Default to 5.5
+and 10.0, respectively. Setting either to a negative value disables
+this functionality.
+
+- percentile
+Which percentile of the frame brightness histogram to use as the source peak
+for tone-mapping. Defaults to 99.995, a fairly conservative value.
+Setting this to 100.0 disables frame histogram measurement and instead
+uses the true peak brightness for tone-mapping.
+
+
+
+
+
39.143.1.6 Tone mapping
+
The options in this section control how libplacebo performs tone-mapping and
+gamut-mapping when dealing with mismatches between wide-gamut or HDR content.
+In general, libplacebo relies on accurate source tagging and mastering display
+gamut information to produce the best results.
+
+- gamut_mode
+How to handle out-of-gamut colors that can occur as a result of colorimetric
+gamut mapping.
+
+- ‘clip’
+Do nothing, simply clip out-of-range colors to the RGB volume. Low quality but
+extremely fast.
+
- ‘perceptual’
+Perceptually soft-clip colors to the gamut volume. This is the default.
+
- ‘relative’
+Relative colorimetric hard-clip. Similar to perceptual but without
+the soft knee.
+
- ‘saturation’
+Saturation mapping, maps primaries directly to primaries in RGB space.
+Not recommended except for artificial computer graphics for which a bright,
+saturated display is desired.
+
- ‘absolute’
+Absolute colorimetric hard-clip. Performs no adjustment of the white point.
+
- ‘desaturate’
+Hard-desaturates out-of-gamut colors towards white, while preserving the
+luminance. Has a tendency to distort the visual appearance of bright objects.
+
- ‘darken’
+Linearly reduces content brightness to preserves saturated details, followed by
+clipping the remaining out-of-gamut colors.
+
- ‘warn’
+Highlight out-of-gamut pixels (by inverting/marking them).
+
- ‘linear’
+Linearly reduces chromaticity of the entire image to make it fit within the
+target color volume. Be careful when using this on BT.2020 sources without
+proper mastering metadata, as doing so will lead to excessive desaturation.
+
+
+- tonemapping
+Tone-mapping algorithm to use. Available values are:
+
+- ‘auto’
+Automatic selection based on internal heuristics. This is the default.
+
- ‘clip’
+Performs no tone-mapping, just clips out-of-range colors. Retains perfect color
+accuracy for in-range colors but completely destroys out-of-range information.
+Does not perform any black point adaptation. Not configurable.
+
- ‘st2094-40’
+EETF from SMPTE ST 2094-40 Annex B, which applies the Bezier curves from HDR10+
+dynamic metadata based on Bezier curves to perform tone-mapping. The OOTF used
+is adjusted based on the ratio between the targeted and actual display peak
+luminances.
+
- ‘st2094-10’
+EETF from SMPTE ST 2094-10 Annex B.2, which takes into account the input signal
+average luminance in addition to the maximum/minimum. The configurable contrast
+parameter influences the slope of the linear output segment, defaulting to
+1.0 for no increase/decrease in contrast. Note that this does not
+currently include the subjective gain/offset/gamma controls defined in Annex
+B.3.
+
- ‘bt.2390’
+EETF from the ITU-R Report BT.2390, a hermite spline roll-off with linear
+segment. The knee point offset is configurable. Note that this parameter
+defaults to 1.0, rather than the value of 0.5 from the ITU-R
+spec.
+
- ‘bt.2446a’
+EETF from ITU-R Report BT.2446, method A. Designed for well-mastered HDR
+sources. Can be used for both forward and inverse tone mapping. Not
+configurable.
+
- ‘spline’
+Simple spline consisting of two polynomials, joined by a single pivot point.
+The parameter gives the pivot point (in PQ space), defaulting to 0.30.
+Can be used for both forward and inverse tone mapping.
+
- ‘reinhard’
+Simple non-linear, global tone mapping algorithm. The parameter specifies the
+local contrast coefficient at the display peak. Essentially, a parameter of
+0.5 implies that the reference white will be about half as bright as
+when clipping. Defaults to 0.5, which results in the simplest
+formulation of this function.
+
- ‘mobius’
+Generalization of the reinhard tone mapping algorithm to support an additional
+linear slope near black. The tone mapping parameter indicates the trade-off
+between the linear section and the non-linear section. Essentially, for a given
+parameter x, every color value below x will be mapped linearly,
+while higher values get non-linearly tone-mapped. Values near 1.0 make
+this curve behave like clip, while values near 0.0 make this
+curve behave like reinhard. The default value is 0.3, which
+provides a good balance between colorimetric accuracy and preserving
+out-of-gamut details.
+
- ‘hable’
+Piece-wise, filmic tone-mapping algorithm developed by John Hable for use in
+Uncharted 2, inspired by a similar tone-mapping algorithm used by Kodak.
+Popularized by its use in video games with HDR rendering. Preserves both dark
+and bright details very well, but comes with the drawback of changing the
+average brightness quite significantly. This is sort of similar to
+reinhard with parameter 0.24.
+
- ‘gamma’
+Fits a gamma (power) function to transfer between the source and target color
+spaces, effectively resulting in a perceptual hard-knee joining two roughly
+linear sections. This preserves details at all scales fairly accurately, but
+can result in an image with a muted or dull appearance. The parameter is used
+as the cutoff point, defaulting to 0.5.
+
- ‘linear’
+Linearly stretches the input range to the output range, in PQ space. This will
+preserve all details accurately, but results in a significantly different
+average brightness. Can be used for inverse tone-mapping in addition to regular
+tone-mapping. The parameter can be used as an additional linear gain
+coefficient (defaulting to 1.0).
+
+
+- tonemapping_param
+For tunable tone mapping functions, this parameter can be used to fine-tune the
+curve behavior. Refer to the documentation of tonemapping. The default
+value of 0.0 is replaced by the curve’s preferred default setting.
+
+- inverse_tonemapping
+If enabled, this filter will also attempt stretching SDR signals to fill HDR
+output color volumes. Disabled by default.
+
+- tonemapping_lut_size
+Size of the tone-mapping LUT, between 2 and 1024. Defaults to
+256. Note that this figure is squared when combined with
+peak_detect.
+
+- hybrid_mix
+If nonzero, this much of the upper range of the tone-mapped result is smoothly
+mixed with a per-channel (LMS) tone-mapped version. Helps avoid unnatural
+blown-out highlights when tone-mapping very bright, strongly saturated colors.
+Defaults to 0.2.
+
+
+
+
+
39.143.1.7 Dithering
+
By default, libplacebo will dither whenever necessary, which includes rendering
+to any integer format below 16-bit precision. It’s recommended to always leave
+this on, since not doing so may result in visible banding in the output, even
+if the debanding filter is enabled. If maximum performance is needed,
+use ordered_fixed instead of disabling dithering.
+
+- dithering
+Dithering method to use. Accepts the following values:
+
+- ‘none’
+Disables dithering completely. May result in visible banding.
+
- ‘blue’
+Dither with pseudo-blue noise. This is the default.
+
- ‘ordered’
+Tunable ordered dither pattern.
+
- ‘ordered_fixed’
+Faster ordered dither with a fixed size of 6. Texture-less.
+
- ‘white’
+Dither with white noise. Texture-less.
+
+
+- dither_lut_size
+Dither LUT size, as log base2 between 1 and 8. Defaults to
+6, corresponding to a LUT size of 64x64.
+
+- dither_temporal
+Enables temporal dithering. Disabled by default.
+
+
+
+
+
+
+
+
39.143.2 Commands
+
This filter supports almost all of the above options as commands.
+
+
+
+
39.143.3 Examples
+
+- Tone-map input to standard gamut BT.709 output:
+
+
libplacebo=colorspace=bt709:color_primaries=bt709:color_trc=bt709:range=tv
+
- Rescale input to fit into standard 1080p, with high quality scaling:
+
+
libplacebo=w=1920:h=1080:force_original_aspect_ratio=decrease:normalize_sar=true:upscaler=ewa_lanczos:downscaler=ewa_lanczos
+
- Interpolate low FPS / VFR input to smoothed constant 60 fps output:
+
+
libplacebo=fps=60:frame_mixer=mitchell_clamp
+
- Convert input to standard sRGB JPEG:
+
+
libplacebo=format=yuv420p:colorspace=bt470bg:color_primaries=bt709:color_trc=iec61966-2-1:range=pc
+
- Use higher quality debanding settings:
+
+
libplacebo=deband=true:deband_iterations=3:deband_radius=8:deband_threshold=6
+
- Run this filter on the CPU, on systems with Mesa installed (and with the most
+expensive options disabled):
+
+
ffmpeg ... -init_hw_device vulkan:llvmpipe ... -vf libplacebo=upscaler=none:downscaler=none:peak_detect=false
+
- Suppress CPU-based AV1/H.274 film grain application in the decoder, in favor of
+doing it with this filter. Note that this is only a gain if the frames are
+either already on the GPU, or if you’re using libplacebo for other purposes,
+since otherwise the VRAM roundtrip will more than offset any expected speedup.
+
+
ffmpeg -export_side_data +film_grain ... -vf libplacebo=apply_filmgrain=true
+
- Interop with VAAPI hwdec to avoid round-tripping through RAM:
+
+
ffmpeg -init_hw_device vulkan -hwaccel vaapi -hwaccel_output_format vaapi ... -vf libplacebo
+
+
+
+
+
+
39.144 libvmaf
+
+
Calulate the VMAF (Video Multi-Method Assessment Fusion) score for a
+reference/distorted pair of input videos.
+
+
The first input is the distorted video, and the second input is the reference video.
+
+
The obtained VMAF score is printed through the logging system.
+
+
It requires Netflix’s vmaf library (libvmaf) as a pre-requisite.
+After installing the library it can be enabled using:
+./configure --enable-libvmaf.
+
+
The filter has following options:
+
+
+- model
+A ‘|‘ delimited list of vmaf models. Each model can be configured with a number of parameters.
+Default value: "version=vmaf_v0.6.1"
+
+- model_path
+Deprecated, use model=’path=...’.
+
+- enable_transform
+Deprecated, use model=’enable_transform=true’.
+
+- phone_model
+Deprecated, use model=’enable_transform=true’.
+
+- enable_conf_interval
+Deprecated, use model=’enable_conf_interval=true’.
+
+- feature
+A ‘|‘ delimited list of features. Each feature can be configured with a number of parameters.
+
+- psnr
+Deprecated, use feature=’name=psnr’.
+
+- ssim
+Deprecated, use feature=’name=ssim’.
+
+- ms_ssim
+Deprecated, use feature=’name=ms_ssim’.
+
+- log_path
+Set the file path to be used to store log files.
+
+- log_fmt
+Set the format of the log file (xml, json, csv, or sub).
+
+- n_threads
+Set number of threads to be used when initializing libvmaf.
+Default value: 0, no threads.
+
+- n_subsample
+Set frame subsampling interval to be used.
+
+
+
This filter also supports the framesync options.
+
+
+
+
39.144.1 Examples
+
+- In the examples below, a distorted video distorted.mpg is
+compared with a reference file reference.mpg.
+
+
- Basic usage:
+
+
ffmpeg -i distorted.mpg -i reference.mpg -lavfi libvmaf=log_path=output.xml -f null -
+
- Example with multiple models:
+
+
ffmpeg -i distorted.mpg -i reference.mpg -lavfi libvmaf='model=version=vmaf_v0.6.1\\:name=vmaf|version=vmaf_v0.6.1neg\\:name=vmaf_neg' -f null -
+
- Example with multiple addtional features:
+
+
ffmpeg -i distorted.mpg -i reference.mpg -lavfi libvmaf='feature=name=psnr|name=ciede' -f null -
+
- Example with options and different containers:
+
+
ffmpeg -i distorted.mpg -i reference.mkv -lavfi "[0:v]settb=AVTB,setpts=PTS-STARTPTS[main];[1:v]settb=AVTB,setpts=PTS-STARTPTS[ref];[main][ref]libvmaf=log_fmt=json:log_path=output.json" -f null -
+
+
+
+
+
+
39.145 limitdiff
+
Apply limited difference filter using second and optionally third video stream.
+
+
The filter accepts the following options:
+
+
+- threshold
+Set the threshold to use when allowing certain differences between video streams.
+Any absolute difference value lower or exact than this threshold will pick pixel components from
+first video stream.
+
+- elasticity
+Set the elasticity of soft thresholding when processing video streams.
+This value multiplied with first one sets second threshold.
+Any absolute difference value greater or exact than second threshold will pick pixel components
+from second video stream. For values between those two threshold
+linear interpolation between first and second video stream will be used.
+
+- reference
+Enable the reference (third) video stream processing. By default is disabled.
+If set, this video stream will be used for calculating absolute difference with first video
+stream.
+
+- planes
+Specify which planes will be processed. Defaults to all available.
+
+
+
+
+
39.145.1 Commands
+
+
This filter supports the all above options as commands except option ‘reference’.
+
+
+
+
+
39.146 limiter
+
+
Limits the pixel components values to the specified range [min, max].
+
+
The filter accepts the following options:
+
+
+- min
+Lower bound. Defaults to the lowest allowed value for the input.
+
+- max
+Upper bound. Defaults to the highest allowed value for the input.
+
+- planes
+Specify which planes will be processed. Defaults to all available.
+
+
+
+
+
39.146.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.147 loop
+
+
Loop video frames.
+
+
The filter accepts the following options:
+
+
+- loop
+Set the number of loops. Setting this value to -1 will result in infinite loops.
+Default is 0.
+
+- size
+Set maximal size in number of frames. Default is 0.
+
+- start
+Set first frame of loop. Default is 0.
+
+- time
+Set the time of loop start in seconds.
+Only used if option named start is set to -1.
+
+
+
+
+
39.147.1 Examples
+
+
+- Loop single first frame infinitely:
+
+
loop=loop=-1:size=1:start=0
+
- Loop single first frame 10 times:
+
+
loop=loop=10:size=1:start=0
+
- Loop 10 first frames 5 times:
+
+
loop=loop=5:size=10:start=0
+
+
+
+
+
+
39.148 lut1d
+
+
Apply a 1D LUT to an input video.
+
+
The filter accepts the following options:
+
+
+- file
+Set the 1D LUT file name.
+
+Currently supported formats:
+
+- ‘cube’
+Iridas
+
- ‘csp’
+cineSpace
+
+
+- interp
+Select interpolation mode.
+
+Available values are:
+
+
+- ‘nearest’
+Use values from the nearest defined point.
+
- ‘linear’
+Interpolate values using the linear interpolation.
+
- ‘cosine’
+Interpolate values using the cosine interpolation.
+
- ‘cubic’
+Interpolate values using the cubic interpolation.
+
- ‘spline’
+Interpolate values using the spline interpolation.
+
+
+
+
+
+
39.148.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.149 lut3d
+
+
Apply a 3D LUT to an input video.
+
+
The filter accepts the following options:
+
+
+- file
+Set the 3D LUT file name.
+
+Currently supported formats:
+
+- ‘3dl’
+AfterEffects
+
- ‘cube’
+Iridas
+
- ‘dat’
+DaVinci
+
- ‘m3d’
+Pandora
+
- ‘csp’
+cineSpace
+
+- interp
+Select interpolation mode.
+
+Available values are:
+
+
+- ‘nearest’
+Use values from the nearest defined point.
+
- ‘trilinear’
+Interpolate values using the 8 points defining a cube.
+
- ‘tetrahedral’
+Interpolate values using a tetrahedron.
+
- ‘pyramid’
+Interpolate values using a pyramid.
+
- ‘prism’
+Interpolate values using a prism.
+
+
+
+
+
+
39.149.1 Commands
+
+
This filter supports the interp option as commands.
+
+
+
+
+
39.150 lumakey
+
+
Turn certain luma values into transparency.
+
+
The filter accepts the following options:
+
+
+- threshold
+Set the luma which will be used as base for transparency.
+Default value is 0.
+
+- tolerance
+Set the range of luma values to be keyed out.
+Default value is 0.01.
+
+- softness
+Set the range of softness. Default value is 0.
+Use this to control gradual transition from zero to full transparency.
+
+
+
+
+
39.150.1 Commands
+
This filter supports same commands as options.
+The command accepts the same syntax of the corresponding option.
+
+
If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
39.151 lut, lutrgb, lutyuv
+
+
Compute a look-up table for binding each pixel component input value
+to an output value, and apply it to the input video.
+
+
lutyuv applies a lookup table to a YUV input video, lutrgb
+to an RGB input video.
+
+
These filters accept the following parameters:
+
+- c0
+set first pixel component expression
+
- c1
+set second pixel component expression
+
- c2
+set third pixel component expression
+
- c3
+set fourth pixel component expression, corresponds to the alpha component
+
+- r
+set red component expression
+
- g
+set green component expression
+
- b
+set blue component expression
+
- a
+alpha component expression
+
+- y
+set Y/luminance component expression
+
- u
+set U/Cb component expression
+
- v
+set V/Cr component expression
+
+
+
Each of them specifies the expression to use for computing the lookup table for
+the corresponding pixel component values.
+
+
The exact component associated to each of the c* options depends on the
+format in input.
+
+
The lut filter requires either YUV or RGB pixel formats in input,
+lutrgb requires RGB pixel formats in input, and lutyuv requires YUV.
+
+
The expressions can contain the following constants and functions:
+
+
+- w
+- h
+The input width and height.
+
+- val
+The input value for the pixel component.
+
+- clipval
+The input value, clipped to the minval-maxval range.
+
+- maxval
+The maximum value for the pixel component.
+
+- minval
+The minimum value for the pixel component.
+
+- negval
+The negated value for the pixel component value, clipped to the
+minval-maxval range; it corresponds to the expression
+"maxval-clipval+minval".
+
+- clip(val)
+The computed value in val, clipped to the
+minval-maxval range.
+
+- gammaval(gamma)
+The computed gamma correction value of the pixel component value,
+clipped to the minval-maxval range. It corresponds to the
+expression
+"pow((clipval-minval)/(maxval-minval)\,gamma)*(maxval-minval)+minval"
+
+
+
+
All expressions default to "clipval".
+
+
+
+
39.151.1 Commands
+
+
This filter supports same commands as options.
+
+
+
+
39.151.2 Examples
+
+
+
+
+
+
+
39.152 lut2, tlut2
+
+
The lut2 filter takes two input streams and outputs one
+stream.
+
+
The tlut2 (time lut2) filter takes two consecutive frames
+from one single stream.
+
+
This filter accepts the following parameters:
+
+- c0
+set first pixel component expression
+
- c1
+set second pixel component expression
+
- c2
+set third pixel component expression
+
- c3
+set fourth pixel component expression, corresponds to the alpha component
+
+- d
+set output bit depth, only available for lut2 filter. By default is 0,
+which means bit depth is automatically picked from first input format.
+
+
+
The lut2 filter also supports the framesync options.
+
+
Each of them specifies the expression to use for computing the lookup table for
+the corresponding pixel component values.
+
+
The exact component associated to each of the c* options depends on the
+format in inputs.
+
+
The expressions can contain the following constants:
+
+
+- w
+- h
+The input width and height.
+
+- x
+The first input value for the pixel component.
+
+- y
+The second input value for the pixel component.
+
+- bdx
+The first input video bit depth.
+
+- bdy
+The second input video bit depth.
+
+
+
All expressions default to "x".
+
+
+
+
39.152.1 Commands
+
+
This filter supports the all above options as commands except option d.
+
+
+
+
39.152.2 Examples
+
+
+- Highlight differences between two RGB video streams:
+
+
lut2='ifnot(x-y,0,pow(2,bdx)-1):ifnot(x-y,0,pow(2,bdx)-1):ifnot(x-y,0,pow(2,bdx)-1)'
+
- Highlight differences between two YUV video streams:
+
+
lut2='ifnot(x-y,0,pow(2,bdx)-1):ifnot(x-y,pow(2,bdx-1),pow(2,bdx)-1):ifnot(x-y,pow(2,bdx-1),pow(2,bdx)-1)'
+
- Show max difference between two video streams:
+
+
lut2='if(lt(x,y),0,if(gt(x,y),pow(2,bdx)-1,pow(2,bdx-1))):if(lt(x,y),0,if(gt(x,y),pow(2,bdx)-1,pow(2,bdx-1))):if(lt(x,y),0,if(gt(x,y),pow(2,bdx)-1,pow(2,bdx-1)))'
+
+
+
+
+
+
39.153 maskedclamp
+
+
Clamp the first input stream with the second input and third input stream.
+
+
Returns the value of first stream to be between second input
+stream - undershoot and third input stream + overshoot.
+
+
This filter accepts the following options:
+
+- undershoot
+Default value is 0.
+
+- overshoot
+Default value is 0.
+
+- planes
+Set which planes will be processed as bitmap, unprocessed planes will be
+copied from first stream.
+By default value 0xf, all planes will be processed.
+
+
+
+
+
39.153.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.154 maskedmax
+
+
Merge the second and third input stream into output stream using absolute differences
+between second input stream and first input stream and absolute difference between
+third input stream and first input stream. The picked value will be from second input
+stream if second absolute difference is greater than first one or from third input stream
+otherwise.
+
+
This filter accepts the following options:
+
+- planes
+Set which planes will be processed as bitmap, unprocessed planes will be
+copied from first stream.
+By default value 0xf, all planes will be processed.
+
+
+
+
+
39.154.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.155 maskedmerge
+
+
Merge the first input stream with the second input stream using per pixel
+weights in the third input stream.
+
+
A value of 0 in the third stream pixel component means that pixel component
+from first stream is returned unchanged, while maximum value (eg. 255 for
+8-bit videos) means that pixel component from second stream is returned
+unchanged. Intermediate values define the amount of merging between both
+input stream’s pixel components.
+
+
This filter accepts the following options:
+
+- planes
+Set which planes will be processed as bitmap, unprocessed planes will be
+copied from first stream.
+By default value 0xf, all planes will be processed.
+
+
+
+
+
39.155.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.156 maskedmin
+
+
Merge the second and third input stream into output stream using absolute differences
+between second input stream and first input stream and absolute difference between
+third input stream and first input stream. The picked value will be from second input
+stream if second absolute difference is less than first one or from third input stream
+otherwise.
+
+
This filter accepts the following options:
+
+- planes
+Set which planes will be processed as bitmap, unprocessed planes will be
+copied from first stream.
+By default value 0xf, all planes will be processed.
+
+
+
+
+
39.156.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.157 maskedthreshold
+
Pick pixels comparing absolute difference of two video streams with fixed
+threshold.
+
+
If absolute difference between pixel component of first and second video
+stream is equal or lower than user supplied threshold than pixel component
+from first video stream is picked, otherwise pixel component from second
+video stream is picked.
+
+
This filter accepts the following options:
+
+- threshold
+Set threshold used when picking pixels from absolute difference from two input
+video streams.
+
+- planes
+Set which planes will be processed as bitmap, unprocessed planes will be
+copied from second stream.
+By default value 0xf, all planes will be processed.
+
+- mode
+Set mode of filter operation. Can be abs or diff.
+Default is abs.
+
+
+
+
+
39.157.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.158 maskfun
+
Create mask from input video.
+
+
For example it is useful to create motion masks after tblend filter.
+
+
This filter accepts the following options:
+
+
+- low
+Set low threshold. Any pixel component lower or exact than this value will be set to 0.
+
+- high
+Set high threshold. Any pixel component higher than this value will be set to max value
+allowed for current pixel format.
+
+- planes
+Set planes to filter, by default all available planes are filtered.
+
+- fill
+Fill all frame pixels with this value.
+
+- sum
+Set max average pixel value for frame. If sum of all pixel components is higher that this
+average, output frame will be completely filled with value set by fill option.
+Typically useful for scene changes when used in combination with tblend filter.
+
+
+
+
+
39.158.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.159 mcdeint
+
+
Apply motion-compensation deinterlacing.
+
+
It needs one field per frame as input and must thus be used together
+with yadif=1/3 or equivalent.
+
+
This filter accepts the following options:
+
+- mode
+Set the deinterlacing mode.
+
+It accepts one of the following values:
+
+- ‘fast’
+- ‘medium’
+- ‘slow’
+use iterative motion estimation
+
- ‘extra_slow’
+like ‘slow’, but use multiple reference frames.
+
+Default value is ‘fast’.
+
+- parity
+Set the picture field parity assumed for the input video. It must be
+one of the following values:
+
+
+- ‘0, tff’
+assume top field first
+
- ‘1, bff’
+assume bottom field first
+
+
+Default value is ‘bff’.
+
+- qp
+Set per-block quantization parameter (QP) used by the internal
+encoder.
+
+Higher values should result in a smoother motion vector field but less
+optimal individual vectors. Default value is 1.
+
+
+
+
+
+
39.161 mergeplanes
+
+
Merge color channel components from several video streams.
+
+
The filter accepts up to 4 input streams, and merge selected input
+planes to the output video.
+
+
This filter accepts the following options:
+
+- mapping
+Set input to output plane mapping. Default is 0.
+
+The mappings is specified as a bitmap. It should be specified as a
+hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. ’Aa’ describes the
+mapping for the first plane of the output stream. ’A’ sets the number of
+the input stream to use (from 0 to 3), and ’a’ the plane number of the
+corresponding input to use (from 0 to 3). The rest of the mappings is
+similar, ’Bb’ describes the mapping for the output stream second
+plane, ’Cc’ describes the mapping for the output stream third plane and
+’Dd’ describes the mapping for the output stream fourth plane.
+
+- format
+Set output pixel format. Default is yuva444p.
+
+- map0s
+- map1s
+- map2s
+- map3s
+Set input to output stream mapping for output Nth plane. Default is 0.
+
+- map0p
+- map1p
+- map2p
+- map3p
+Set input to output plane mapping for output Nth plane. Default is 0.
+
+
+
+
+
39.161.1 Examples
+
+
+- Merge three gray video streams of same width and height into single video stream:
+
+
[a0][a1][a2]mergeplanes=0x001020:yuv444p
+
- Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
+
+
[a0][a1]mergeplanes=0x00010210:yuva444p
+
- Swap Y and A plane in yuva444p stream:
+
+
format=yuva444p,mergeplanes=0x03010200:yuva444p
+
- Swap U and V plane in yuv420p stream:
+
+
format=yuv420p,mergeplanes=0x000201:yuv420p
+
- Cast a rgb24 clip to yuv444p:
+
+
format=rgb24,mergeplanes=0x000102:yuv444p
+
+
+
+
+
+
39.162 mestimate
+
+
Estimate and export motion vectors using block matching algorithms.
+Motion vectors are stored in frame side data to be used by other filters.
+
+
This filter accepts the following options:
+
+- method
+Specify the motion estimation method. Accepts one of the following values:
+
+
+- ‘esa’
+Exhaustive search algorithm.
+
- ‘tss’
+Three step search algorithm.
+
- ‘tdls’
+Two dimensional logarithmic search algorithm.
+
- ‘ntss’
+New three step search algorithm.
+
- ‘fss’
+Four step search algorithm.
+
- ‘ds’
+Diamond search algorithm.
+
- ‘hexbs’
+Hexagon-based search algorithm.
+
- ‘epzs’
+Enhanced predictive zonal search algorithm.
+
- ‘umh’
+Uneven multi-hexagon search algorithm.
+
+Default value is ‘esa’.
+
+- mb_size
+Macroblock size. Default 16.
+
+- search_param
+Search parameter. Default 7.
+
+
+
+
+
39.163 midequalizer
+
+
Apply Midway Image Equalization effect using two video streams.
+
+
Midway Image Equalization adjusts a pair of images to have the same
+histogram, while maintaining their dynamics as much as possible. It’s
+useful for e.g. matching exposures from a pair of stereo cameras.
+
+
This filter has two inputs and one output, which must be of same pixel format, but
+may be of different sizes. The output of filter is first input adjusted with
+midway histogram of both inputs.
+
+
This filter accepts the following option:
+
+
+- planes
+Set which planes to process. Default is 15, which is all available planes.
+
+
+
+
+
39.164 minterpolate
+
+
Convert the video to specified frame rate using motion interpolation.
+
+
This filter accepts the following options:
+
+- fps
+Specify the output frame rate. This can be rational e.g. 60000/1001. Frames are dropped if fps is lower than source fps. Default 60.
+
+- mi_mode
+Motion interpolation mode. Following values are accepted:
+
+- ‘dup’
+Duplicate previous or next frame for interpolating new ones.
+
- ‘blend’
+Blend source frames. Interpolated frame is mean of previous and next frames.
+
- ‘mci’
+Motion compensated interpolation. Following options are effective when this mode is selected:
+
+
+- ‘mc_mode’
+Motion compensation mode. Following values are accepted:
+
+- ‘obmc’
+Overlapped block motion compensation.
+
- ‘aobmc’
+Adaptive overlapped block motion compensation. Window weighting coefficients are controlled adaptively according to the reliabilities of the neighboring motion vectors to reduce oversmoothing.
+
+Default mode is ‘obmc’.
+
+- ‘me_mode’
+Motion estimation mode. Following values are accepted:
+
+- ‘bidir’
+Bidirectional motion estimation. Motion vectors are estimated for each source frame in both forward and backward directions.
+
- ‘bilat’
+Bilateral motion estimation. Motion vectors are estimated directly for interpolated frame.
+
+Default mode is ‘bilat’.
+
+- ‘me’
+The algorithm to be used for motion estimation. Following values are accepted:
+
+- ‘esa’
+Exhaustive search algorithm.
+
- ‘tss’
+Three step search algorithm.
+
- ‘tdls’
+Two dimensional logarithmic search algorithm.
+
- ‘ntss’
+New three step search algorithm.
+
- ‘fss’
+Four step search algorithm.
+
- ‘ds’
+Diamond search algorithm.
+
- ‘hexbs’
+Hexagon-based search algorithm.
+
- ‘epzs’
+Enhanced predictive zonal search algorithm.
+
- ‘umh’
+Uneven multi-hexagon search algorithm.
+
+Default algorithm is ‘epzs’.
+
+- ‘mb_size’
+Macroblock size. Default 16.
+
+- ‘search_param’
+Motion estimation search parameter. Default 32.
+
+- ‘vsbmc’
+Enable variable-size block motion compensation. Motion estimation is applied with smaller block sizes at object boundaries in order to make the them less blur. Default is 0 (disabled).
+
+
+
+- scd
+Scene change detection method. Scene change leads motion vectors to be in random direction. Scene change detection replace interpolated frames by duplicate ones. May not be needed for other modes. Following values are accepted:
+
+- ‘none’
+Disable scene change detection.
+
- ‘fdiff’
+Frame difference. Corresponding pixel values are compared and if it satisfies scd_threshold scene change is detected.
+
+Default method is ‘fdiff’.
+
+- scd_threshold
+Scene change detection threshold. Default is 10..
+
+
+
+
+
39.165 mix
+
+
Mix several video input streams into one video stream.
+
+
A description of the accepted options follows.
+
+
+- inputs
+The number of inputs. If unspecified, it defaults to 2.
+
+- weights
+Specify weight of each input video stream as sequence.
+Each weight is separated by space. If number of weights
+is smaller than number of frames last specified
+weight will be used for all remaining unset weights.
+
+- scale
+Specify scale, if it is set it will be multiplied with sum
+of each weight multiplied with pixel values to give final destination
+pixel value. By default scale is auto scaled to sum of weights.
+
+- planes
+Set which planes to filter. Default is all. Allowed range is from 0 to 15.
+
+- duration
+Specify how end of stream is determined.
+
+- ‘longest’
+The duration of the longest input. (default)
+
+- ‘shortest’
+The duration of the shortest input.
+
+- ‘first’
+The duration of the first input.
+
+
+
+
+
+
39.165.1 Commands
+
+
This filter supports the following commands:
+
+- weights
+- scale
+- planes
+Syntax is same as option with same name.
+
+
+
+
+
+
39.166 monochrome
+
Convert video to gray using custom color filter.
+
+
A description of the accepted options follows.
+
+
+- cb
+Set the chroma blue spot. Allowed range is from -1 to 1.
+Default value is 0.
+
+- cr
+Set the chroma red spot. Allowed range is from -1 to 1.
+Default value is 0.
+
+- size
+Set the color filter size. Allowed range is from .1 to 10.
+Default value is 1.
+
+- high
+Set the highlights strength. Allowed range is from 0 to 1.
+Default value is 0.
+
+
+
+
+
39.166.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.167 morpho
+
+
This filter allows to apply main morphological grayscale transforms,
+erode and dilate with arbitrary structures set in second input stream.
+
+
Unlike naive implementation and much slower performance in erosion
+and dilation filters, when speed is critical morpho filter
+should be used instead.
+
+
A description of accepted options follows,
+
+
+- mode
+Set morphological transform to apply, can be:
+
+
+- ‘erode’
+- ‘dilate’
+- ‘open’
+- ‘close’
+- ‘gradient’
+- ‘tophat’
+- ‘blackhat’
+
+Default is erode.
+
+- planes
+Set planes to filter, by default all planes except alpha are filtered.
+
+- structure
+Set which structure video frames will be processed from second input stream,
+can be first or all. Default is all.
+
+
+
The morpho filter also supports the framesync options.
+
+
+
+
39.167.1 Commands
+
+
This filter supports same commands as options.
+
+
+
+
+
39.168 mpdecimate
+
+
Drop frames that do not differ greatly from the previous frame in
+order to reduce frame rate.
+
+
The main use of this filter is for very-low-bitrate encoding
+(e.g. streaming over dialup modem), but it could in theory be used for
+fixing movies that were inverse-telecined incorrectly.
+
+
A description of the accepted options follows.
+
+
+- max
+Set the maximum number of consecutive frames which can be dropped (if
+positive), or the minimum interval between dropped frames (if
+negative). If the value is 0, the frame is dropped disregarding the
+number of previous sequentially dropped frames.
+
+Default value is 0.
+
+- keep
+Set the maximum number of consecutive similar frames to ignore before to start dropping them.
+If the value is 0, the frame is dropped disregarding the
+number of previous sequentially similar frames.
+
+Default value is 0.
+
+- hi
+- lo
+- frac
+Set the dropping threshold values.
+
+Values for hi and lo are for 8x8 pixel blocks and
+represent actual pixel value differences, so a threshold of 64
+corresponds to 1 unit of difference for each pixel, or the same spread
+out differently over the block.
+
+A frame is a candidate for dropping if no 8x8 blocks differ by more
+than a threshold of hi, and if no more than frac blocks (1
+meaning the whole image) differ by more than a threshold of lo.
+
+Default value for hi is 64*12, default value for lo is
+64*5, and default value for frac is 0.33.
+
+
+
+
+
39.169 msad
+
+
Obtain the MSAD (Mean Sum of Absolute Differences) between two input videos.
+
+
This filter takes two input videos.
+
+
Both input videos must have the same resolution and pixel format for
+this filter to work correctly. Also it assumes that both inputs
+have the same number of frames, which are compared one by one.
+
+
The obtained per component, average, min and max MSAD is printed through
+the logging system.
+
+
The filter stores the calculated MSAD of each frame in frame metadata.
+
+
This filter also supports the framesync options.
+
+
In the below example the input file main.mpg being processed is compared
+with the reference file ref.mpg.
+
+
+
ffmpeg -i main.mpg -i ref.mpg -lavfi msad -f null -
+
+
+
+
+
39.170 multiply
+
Multiply first video stream pixels values with second video stream pixels values.
+
+
The filter accepts the following options:
+
+
+- scale
+Set the scale applied to second video stream. By default is 1.
+Allowed range is from 0 to 9.
+
+- offset
+Set the offset applied to second video stream. By default is 0.5.
+Allowed range is from -1 to 1.
+
+- planes
+Specify planes from input video stream that will be processed.
+By default all planes are processed.
+
+
+
+
+
39.170.1 Commands
+
+
This filter supports same commands as options.
+
+
+
+
+
39.171 negate
+
+
Negate (invert) the input video.
+
+
It accepts the following option:
+
+
+- components
+Set components to negate.
+
+Available values for components are:
+
+- ‘y’
+- ‘u’
+- ‘v’
+- ‘a’
+- ‘r’
+- ‘g’
+- ‘b’
+
+
+- negate_alpha
+With value 1, it negates the alpha component, if present. Default value is 0.
+
+
+
+
+
39.171.1 Commands
+
+
This filter supports same commands as options.
+
+
+
+
+
39.172 nlmeans
+
+
Denoise frames using Non-Local Means algorithm.
+
+
Each pixel is adjusted by looking for other pixels with similar contexts. This
+context similarity is defined by comparing their surrounding patches of size
+pxp. Patches are searched in an area of rxr
+around the pixel.
+
+
Note that the research area defines centers for patches, which means some
+patches will be made of pixels outside that research area.
+
+
The filter accepts the following options.
+
+
+- s
+Set denoising strength. Default is 1.0. Must be in range [1.0, 30.0].
+
+- p
+Set patch size. Default is 7. Must be odd number in range [0, 99].
+
+- pc
+Same as p but for chroma planes.
+
+The default value is 0 and means automatic.
+
+- r
+Set research size. Default is 15. Must be odd number in range [0, 99].
+
+- rc
+Same as r but for chroma planes.
+
+The default value is 0 and means automatic.
+
+
+
+
+
39.173 nnedi
+
+
Deinterlace video using neural network edge directed interpolation.
+
+
This filter accepts the following options:
+
+
+- weights
+Mandatory option, without binary file filter can not work.
+Currently file can be found here:
+https://github.com/dubhater/vapoursynth-nnedi3/blob/master/src/nnedi3_weights.bin
+
+- deint
+Set which frames to deinterlace, by default it is all.
+Can be all or interlaced.
+
+- field
+Set mode of operation.
+
+Can be one of the following:
+
+
+- ‘af’
+Use frame flags, both fields.
+
- ‘a’
+Use frame flags, single field.
+
- ‘t’
+Use top field only.
+
- ‘b’
+Use bottom field only.
+
- ‘tf’
+Use both fields, top first.
+
- ‘bf’
+Use both fields, bottom first.
+
+
+- planes
+Set which planes to process, by default filter process all frames.
+
+- nsize
+Set size of local neighborhood around each pixel, used by the predictor neural
+network.
+
+Can be one of the following:
+
+
+- ‘s8x6’
+- ‘s16x6’
+- ‘s32x6’
+- ‘s48x6’
+- ‘s8x4’
+- ‘s16x4’
+- ‘s32x4’
+
+
+- nns
+Set the number of neurons in predictor neural network.
+Can be one of the following:
+
+
+- ‘n16’
+- ‘n32’
+- ‘n64’
+- ‘n128’
+- ‘n256’
+
+
+- qual
+Controls the number of different neural network predictions that are blended
+together to compute the final output value. Can be fast, default or
+slow.
+
+- etype
+Set which set of weights to use in the predictor.
+Can be one of the following:
+
+
+- ‘a, abs’
+weights trained to minimize absolute error
+
- ‘s, mse’
+weights trained to minimize squared error
+
+
+- pscrn
+Controls whether or not the prescreener neural network is used to decide
+which pixels should be processed by the predictor neural network and which
+can be handled by simple cubic interpolation.
+The prescreener is trained to know whether cubic interpolation will be
+sufficient for a pixel or whether it should be predicted by the predictor nn.
+The computational complexity of the prescreener nn is much less than that of
+the predictor nn. Since most pixels can be handled by cubic interpolation,
+using the prescreener generally results in much faster processing.
+The prescreener is pretty accurate, so the difference between using it and not
+using it is almost always unnoticeable.
+
+Can be one of the following:
+
+
+- ‘none’
+- ‘original’
+- ‘new’
+- ‘new2’
+- ‘new3’
+
+
+Default is new.
+
+
+
+
+
39.173.1 Commands
+
This filter supports same commands as options, excluding weights option.
+
+
+
+
+
+
39.175 noise
+
+
Add noise on video input frame.
+
+
The filter accepts the following options:
+
+
+- all_seed
+- c0_seed
+- c1_seed
+- c2_seed
+- c3_seed
+Set noise seed for specific pixel component or all pixel components in case
+of all_seed. Default value is 123457.
+
+- all_strength, alls
+- c0_strength, c0s
+- c1_strength, c1s
+- c2_strength, c2s
+- c3_strength, c3s
+Set noise strength for specific pixel component or all pixel components in case
+all_strength. Default value is 0. Allowed range is [0, 100].
+
+- all_flags, allf
+- c0_flags, c0f
+- c1_flags, c1f
+- c2_flags, c2f
+- c3_flags, c3f
+Set pixel component flags or set flags for all components if all_flags.
+Available values for component flags are:
+
+- ‘a’
+averaged temporal noise (smoother)
+
- ‘p’
+mix random noise with a (semi)regular pattern
+
- ‘t’
+temporal noise (noise pattern changes between frames)
+
- ‘u’
+uniform noise (gaussian otherwise)
+
+
+
+
+
+
39.175.1 Examples
+
+
Add temporal and uniform noise to input video:
+
+
noise=alls=20:allf=t+u
+
+
+
+
+
+
39.176 normalize
+
+
Normalize RGB video (aka histogram stretching, contrast stretching).
+See: https://en.wikipedia.org/wiki/Normalization_(image_processing)
+
+
For each channel of each frame, the filter computes the input range and maps
+it linearly to the user-specified output range. The output range defaults
+to the full dynamic range from pure black to pure white.
+
+
Temporal smoothing can be used on the input range to reduce flickering (rapid
+changes in brightness) caused when small dark or bright objects enter or leave
+the scene. This is similar to the auto-exposure (automatic gain control) on a
+video camera, and, like a video camera, it may cause a period of over- or
+under-exposure of the video.
+
+
The R,G,B channels can be normalized independently, which may cause some
+color shifting, or linked together as a single channel, which prevents
+color shifting. Linked normalization preserves hue. Independent normalization
+does not, so it can be used to remove some color casts. Independent and linked
+normalization can be combined in any ratio.
+
+
The normalize filter accepts the following options:
+
+
+- blackpt
+- whitept
+Colors which define the output range. The minimum input value is mapped to
+the blackpt. The maximum input value is mapped to the whitept.
+The defaults are black and white respectively. Specifying white for
+blackpt and black for whitept will give color-inverted,
+normalized video. Shades of grey can be used to reduce the dynamic range
+(contrast). Specifying saturated colors here can create some interesting
+effects.
+
+- smoothing
+The number of previous frames to use for temporal smoothing. The input range
+of each channel is smoothed using a rolling average over the current frame
+and the smoothing previous frames. The default is 0 (no temporal
+smoothing).
+
+- independence
+Controls the ratio of independent (color shifting) channel normalization to
+linked (color preserving) normalization. 0.0 is fully linked, 1.0 is fully
+independent. Defaults to 1.0 (fully independent).
+
+- strength
+Overall strength of the filter. 1.0 is full strength. 0.0 is a rather
+expensive no-op. Defaults to 1.0 (full strength).
+
+
+
+
+
+
39.176.1 Commands
+
This filter supports same commands as options, excluding smoothing option.
+The command accepts the same syntax of the corresponding option.
+
+
If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
39.176.2 Examples
+
+
Stretch video contrast to use the full dynamic range, with no temporal
+smoothing; may flicker depending on the source content:
+
+
normalize=blackpt=black:whitept=white:smoothing=0
+
+
+
As above, but with 50 frames of temporal smoothing; flicker should be
+reduced, depending on the source content:
+
+
normalize=blackpt=black:whitept=white:smoothing=50
+
+
+
As above, but with hue-preserving linked channel normalization:
+
+
normalize=blackpt=black:whitept=white:smoothing=50:independence=0
+
+
+
As above, but with half strength:
+
+
normalize=blackpt=black:whitept=white:smoothing=50:independence=0:strength=0.5
+
+
+
Map the darkest input color to red, the brightest input color to cyan:
+
+
normalize=blackpt=red:whitept=cyan
+
+
+
+
+
+
39.177 null
+
+
Pass the video source unchanged to the output.
+
+
+
+
39.178 ocr
+
Optical Character Recognition
+
+
This filter uses Tesseract for optical character recognition. To enable
+compilation of this filter, you need to configure FFmpeg with
+--enable-libtesseract.
+
+
It accepts the following options:
+
+
+- datapath
+Set datapath to tesseract data. Default is to use whatever was
+set at installation.
+
+- language
+Set language, default is "eng".
+
+- whitelist
+Set character whitelist.
+
+- blacklist
+Set character blacklist.
+
+
+
The filter exports recognized text as the frame metadata lavfi.ocr.text.
+The filter exports confidence of recognized words as the frame metadata lavfi.ocr.confidence.
+
+
+
+
39.179 ocv
+
+
Apply a video transform using libopencv.
+
+
To enable this filter, install the libopencv library and headers and
+configure FFmpeg with --enable-libopencv.
+
+
It accepts the following parameters:
+
+
+- filter_name
+The name of the libopencv filter to apply.
+
+- filter_params
+The parameters to pass to the libopencv filter. If not specified, the default
+values are assumed.
+
+
+
+
Refer to the official libopencv documentation for more precise
+information:
+http://docs.opencv.org/master/modules/imgproc/doc/filtering.html
+
+
Several libopencv filters are supported; see the following subsections.
+
+
+
+
39.179.1 dilate
+
+
Dilate an image by using a specific structuring element.
+It corresponds to the libopencv function cvDilate.
+
+
It accepts the parameters: struct_el|nb_iterations.
+
+
struct_el represents a structuring element, and has the syntax:
+colsxrows+anchor_xxanchor_y/shape
+
+
cols and rows represent the number of columns and rows of
+the structuring element, anchor_x and anchor_y the anchor
+point, and shape the shape for the structuring element. shape
+must be "rect", "cross", "ellipse", or "custom".
+
+
If the value for shape is "custom", it must be followed by a
+string of the form "=filename". The file with name
+filename is assumed to represent a binary image, with each
+printable character corresponding to a bright pixel. When a custom
+shape is used, cols and rows are ignored, the number
+or columns and rows of the read file are assumed instead.
+
+
The default value for struct_el is "3x3+0x0/rect".
+
+
nb_iterations specifies the number of times the transform is
+applied to the image, and defaults to 1.
+
+
Some examples:
+
+
# Use the default values
+ocv=dilate
+
+# Dilate using a structuring element with a 5x5 cross, iterating two times
+ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
+
+# Read the shape from the file diamond.shape, iterating two times.
+# The file diamond.shape may contain a pattern of characters like this
+# *
+# ***
+# *****
+# ***
+# *
+# The specified columns and rows are ignored
+# but the anchor point coordinates are not
+ocv=dilate:0x0+2x2/custom=diamond.shape|2
+
+
+
+
+
39.179.2 erode
+
+
Erode an image by using a specific structuring element.
+It corresponds to the libopencv function cvErode.
+
+
It accepts the parameters: struct_el:nb_iterations,
+with the same syntax and semantics as the dilate filter.
+
+
+
+
39.179.3 smooth
+
+
Smooth the input video.
+
+
The filter takes the following parameters:
+type|param1|param2|param3|param4.
+
+
type is the type of smooth filter to apply, and must be one of
+the following values: "blur", "blur_no_scale", "median", "gaussian",
+or "bilateral". The default value is "gaussian".
+
+
The meaning of param1, param2, param3, and param4
+depends on the smooth type. param1 and
+param2 accept integer positive values or 0. param3 and
+param4 accept floating point values.
+
+
The default value for param1 is 3. The default value for the
+other parameters is 0.
+
+
These parameters correspond to the parameters assigned to the
+libopencv function cvSmooth.
+
+
+
+
+
39.180 oscilloscope
+
+
2D Video Oscilloscope.
+
+
Useful to measure spatial impulse, step responses, chroma delays, etc.
+
+
It accepts the following parameters:
+
+
+- x
+Set scope center x position.
+
+- y
+Set scope center y position.
+
+- s
+Set scope size, relative to frame diagonal.
+
+- t
+Set scope tilt/rotation.
+
+- o
+Set trace opacity.
+
+- tx
+Set trace center x position.
+
+- ty
+Set trace center y position.
+
+- tw
+Set trace width, relative to width of frame.
+
+- th
+Set trace height, relative to height of frame.
+
+- c
+Set which components to trace. By default it traces first three components.
+
+- g
+Draw trace grid. By default is enabled.
+
+- st
+Draw some statistics. By default is enabled.
+
+- sc
+Draw scope. By default is enabled.
+
+
+
+
+
39.180.1 Commands
+
This filter supports same commands as options.
+The command accepts the same syntax of the corresponding option.
+
+
If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
39.180.2 Examples
+
+
+- Inspect full first row of video frame.
+
+
oscilloscope=x=0.5:y=0:s=1
+
- Inspect full last row of video frame.
+
+
oscilloscope=x=0.5:y=1:s=1
+
- Inspect full 5th line of video frame of height 1080.
+
+
oscilloscope=x=0.5:y=5/1080:s=1
+
- Inspect full last column of video frame.
+
+
oscilloscope=x=1:y=0.5:s=1:t=1
+
+
+
+
+
+
39.181 overlay
+
+
Overlay one video on top of another.
+
+
It takes two inputs and has one output. The first input is the "main"
+video on which the second input is overlaid.
+
+
It accepts the following parameters:
+
+
A description of the accepted options follows.
+
+
+- x
+- y
+Set the expression for the x and y coordinates of the overlaid video
+on the main video. Default value is "0" for both expressions. In case
+the expression is invalid, it is set to a huge value (meaning that the
+overlay will not be displayed within the output visible area).
+
+- eof_action
+See framesync.
+
+- eval
+Set when the expressions for x, and y are evaluated.
+
+It accepts the following values:
+
+- ‘init’
+only evaluate expressions once during the filter initialization or
+when a command is processed
+
+- ‘frame’
+evaluate expressions for each incoming frame
+
+
+Default value is ‘frame’.
+
+- shortest
+See framesync.
+
+- format
+Set the format for the output video.
+
+It accepts the following values:
+
+- ‘yuv420’
+force YUV420 output
+
+- ‘yuv420p10’
+force YUV420p10 output
+
+- ‘yuv422’
+force YUV422 output
+
+- ‘yuv422p10’
+force YUV422p10 output
+
+- ‘yuv444’
+force YUV444 output
+
+- ‘rgb’
+force packed RGB output
+
+- ‘gbrp’
+force planar RGB output
+
+- ‘auto’
+automatically pick format
+
+
+Default value is ‘yuv420’.
+
+- repeatlast
+See framesync.
+
+- alpha
+Set format of alpha of the overlaid video, it can be straight or
+premultiplied. Default is straight.
+
+
+
The x, and y expressions can contain the following
+parameters.
+
+
+- main_w, W
+- main_h, H
+The main input width and height.
+
+- overlay_w, w
+- overlay_h, h
+The overlay input width and height.
+
+- x
+- y
+The computed values for x and y. They are evaluated for
+each new frame.
+
+- hsub
+- vsub
+horizontal and vertical chroma subsample values of the output
+format. For example for the pixel format "yuv422p" hsub is 2 and
+vsub is 1.
+
+- n
+the number of input frame, starting from 0
+
+- pos
+the position in the file of the input frame, NAN if unknown; deprecated,
+do not use
+
+- t
+The timestamp, expressed in seconds. It’s NAN if the input timestamp is unknown.
+
+
+
+
This filter also supports the framesync options.
+
+
Note that the n, t variables are available only
+when evaluation is done per frame, and will evaluate to NAN
+when eval is set to ‘init’.
+
+
Be aware that frames are taken from each input video in timestamp
+order, hence, if their initial timestamps differ, it is a good idea
+to pass the two inputs through a setpts=PTS-STARTPTS filter to
+have them begin in the same zero timestamp, as the example for
+the movie filter does.
+
+
You can chain together more overlays but you should test the
+efficiency of such approach.
+
+
+
+
39.181.1 Commands
+
+
This filter supports the following commands:
+
+- x
+- y
+Modify the x and y of the overlay input.
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
39.181.2 Examples
+
+
+
+
+
+
+
39.182 overlay_cuda
+
+
Overlay one video on top of another.
+
+
This is the CUDA variant of the overlay filter.
+It only accepts CUDA frames. The underlying input pixel formats have to match.
+
+
It takes two inputs and has one output. The first input is the "main"
+video on which the second input is overlaid.
+
+
It accepts the following parameters:
+
+
+- x
+- y
+Set expressions for the x and y coordinates of the overlaid video
+on the main video.
+
+They can contain the following parameters:
+
+
+- main_w, W
+- main_h, H
+The main input width and height.
+
+- overlay_w, w
+- overlay_h, h
+The overlay input width and height.
+
+- x
+- y
+The computed values for x and y. They are evaluated for
+each new frame.
+
+- n
+The ordinal index of the main input frame, starting from 0.
+
+- pos
+The byte offset position in the file of the main input frame, NAN if unknown.
+Deprecated, do not use.
+
+- t
+The timestamp of the main input frame, expressed in seconds, NAN if unknown.
+
+
+
+Default value is "0" for both expressions.
+
+- eval
+Set when the expressions for x and y are evaluated.
+
+It accepts the following values:
+
+- init
+Evaluate expressions once during filter initialization or
+when a command is processed.
+
+- frame
+Evaluate expressions for each incoming frame
+
+
+Default value is frame.
+
+- eof_action
+See framesync.
+
+- shortest
+See framesync.
+
+- repeatlast
+See framesync.
+
+
+
+
This filter also supports the framesync options.
+
+
+
+
39.183 owdenoise
+
+
Apply Overcomplete Wavelet denoiser.
+
+
The filter accepts the following options:
+
+
+- depth
+Set depth.
+
+Larger depth values will denoise lower frequency components more, but
+slow down filtering.
+
+Must be an int in the range 8-16, default is 8.
+
+- luma_strength, ls
+Set luma strength.
+
+Must be a double value in the range 0-1000, default is 1.0.
+
+- chroma_strength, cs
+Set chroma strength.
+
+Must be a double value in the range 0-1000, default is 1.0.
+
+
+
+
+
39.184 pad
+
+
Add paddings to the input image, and place the original input at the
+provided x, y coordinates.
+
+
It accepts the following parameters:
+
+
+- width, w
+- height, h
+Specify an expression for the size of the output image with the
+paddings added. If the value for width or height is 0, the
+corresponding input size is used for the output.
+
+The width expression can reference the value set by the
+height expression, and vice versa.
+
+The default value of width and height is 0.
+
+- x
+- y
+Specify the offsets to place the input image at within the padded area,
+with respect to the top/left border of the output image.
+
+The x expression can reference the value set by the y
+expression, and vice versa.
+
+The default value of x and y is 0.
+
+If x or y evaluate to a negative number, they’ll be changed
+so the input image is centered on the padded area.
+
+- color
+Specify the color of the padded area. For the syntax of this option,
+check the (ffmpeg-utils)"Color" section in the ffmpeg-utils
+manual.
+
+The default value of color is "black".
+
+- eval
+Specify when to evaluate width, height, x and y expression.
+
+It accepts the following values:
+
+
+- ‘init’
+Only evaluate expressions once during the filter initialization or when
+a command is processed.
+
+- ‘frame’
+Evaluate expressions for each incoming frame.
+
+
+
+Default value is ‘init’.
+
+- aspect
+Pad to aspect instead to a resolution.
+
+
+
+
The value for the width, height, x, and y
+options are expressions containing the following constants:
+
+
+- in_w
+- in_h
+The input video width and height.
+
+- iw
+- ih
+These are the same as in_w and in_h.
+
+- out_w
+- out_h
+The output width and height (the size of the padded area), as
+specified by the width and height expressions.
+
+- ow
+- oh
+These are the same as out_w and out_h.
+
+- x
+- y
+The x and y offsets as specified by the x and y
+expressions, or NAN if not yet specified.
+
+- a
+same as iw / ih
+
+- sar
+input sample aspect ratio
+
+- dar
+input display aspect ratio, it is the same as (iw / ih) * sar
+
+- hsub
+- vsub
+The horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" hsub is 2 and vsub is 1.
+
+
+
+
+
39.184.1 Examples
+
+
+
+
+
+
+
39.185 palettegen
+
+
Generate one palette for a whole video stream.
+
+
It accepts the following options:
+
+
+- max_colors
+Set the maximum number of colors to quantize in the palette.
+Note: the palette will still contain 256 colors; the unused palette entries
+will be black.
+
+- reserve_transparent
+Create a palette of 255 colors maximum and reserve the last one for
+transparency. Reserving the transparency color is useful for GIF optimization.
+If not set, the maximum of colors in the palette will be 256. You probably want
+to disable this option for a standalone image.
+Set by default.
+
+- transparency_color
+Set the color that will be used as background for transparency.
+
+- stats_mode
+Set statistics mode.
+
+It accepts the following values:
+
+- ‘full’
+Compute full frame histograms.
+
- ‘diff’
+Compute histograms only for the part that differs from previous frame. This
+might be relevant to give more importance to the moving part of your input if
+the background is static.
+
- ‘single’
+Compute new histogram for each frame.
+
+
+Default value is full.
+
+
+
The filter also exports the frame metadata lavfi.color_quant_ratio
+(nb_color_in / nb_color_out) which you can use to evaluate the degree of
+color quantization of the palette. This information is also visible at
+info logging level.
+
+
+
+
39.185.1 Examples
+
+
+- Generate a representative palette of a given video using
ffmpeg:
+
+
ffmpeg -i input.mkv -vf palettegen palette.png
+
+
+
+
+
+
39.186 paletteuse
+
+
Use a palette to downsample an input video stream.
+
+
The filter takes two inputs: one video stream and a palette. The palette must
+be a 256 pixels image.
+
+
It accepts the following options:
+
+
+- dither
+Select dithering mode. Available algorithms are:
+
+- ‘bayer’
+Ordered 8x8 bayer dithering (deterministic)
+
- ‘heckbert’
+Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
+Note: this dithering is sometimes considered "wrong" and is included as a
+reference.
+
- ‘floyd_steinberg’
+Floyd and Steingberg dithering (error diffusion)
+
- ‘sierra2’
+Frankie Sierra dithering v2 (error diffusion)
+
- ‘sierra2_4a’
+Frankie Sierra dithering v2 "Lite" (error diffusion)
+
- ‘sierra3’
+Frankie Sierra dithering v3 (error diffusion)
+
- ‘burkes’
+Burkes dithering (error diffusion)
+
- ‘atkinson’
+Atkinson dithering by Bill Atkinson at Apple Computer (error diffusion)
+
- ‘none’
+Disable dithering.
+
+
+Default is sierra2_4a.
+
+- bayer_scale
+When bayer dithering is selected, this option defines the scale of the
+pattern (how much the crosshatch pattern is visible). A low value means more
+visible pattern for less banding, and higher value means less visible pattern
+at the cost of more banding.
+
+The option must be an integer value in the range [0,5]. Default is 2.
+
+- diff_mode
+If set, define the zone to process
+
+
+- ‘rectangle’
+Only the changing rectangle will be reprocessed. This is similar to GIF
+cropping/offsetting compression mechanism. This option can be useful for speed
+if only a part of the image is changing, and has use cases such as limiting the
+scope of the error diffusal dither to the rectangle that bounds the
+moving scene (it leads to more deterministic output if the scene doesn’t change
+much, and as a result less moving noise and better GIF compression).
+
+
+Default is none.
+
+- new
+Take new palette for each output frame.
+
+- alpha_threshold
+Sets the alpha threshold for transparency. Alpha values above this threshold
+will be treated as completely opaque, and values below this threshold will be
+treated as completely transparent.
+
+The option must be an integer value in the range [0,255]. Default is 128.
+
+
+
+
+
39.186.1 Examples
+
+
+- Use a palette (generated for example with palettegen) to encode a GIF
+using
ffmpeg:
+
+
ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
+
+
+
+
+
+
39.187 perspective
+
+
Correct perspective of video not recorded perpendicular to the screen.
+
+
A description of the accepted parameters follows.
+
+
+- x0
+- y0
+- x1
+- y1
+- x2
+- y2
+- x3
+- y3
+Set coordinates expression for top left, top right, bottom left and bottom right corners.
+Default values are 0:0:W:0:0:H:W:H with which perspective will remain unchanged.
+If the sense option is set to source, then the specified points will be sent
+to the corners of the destination. If the sense option is set to destination,
+then the corners of the source will be sent to the specified coordinates.
+
+The expressions can use the following variables:
+
+
+- W
+- H
+the width and height of video frame.
+
- in
+Input frame count.
+
- on
+Output frame count.
+
+
+- interpolation
+Set interpolation for perspective correction.
+
+It accepts the following values:
+
+- ‘linear’
+- ‘cubic’
+
+
+Default value is ‘linear’.
+
+- sense
+Set interpretation of coordinate options.
+
+It accepts the following values:
+
+- ‘0, source’
+-
+
Send point in the source specified by the given coordinates to
+the corners of the destination.
+
+
+- ‘1, destination’
+-
+
Send the corners of the source to the point in the destination specified
+by the given coordinates.
+
+Default value is ‘source’.
+
+
+
+- eval
+Set when the expressions for coordinates x0,y0,...x3,y3 are evaluated.
+
+It accepts the following values:
+
+- ‘init’
+only evaluate expressions once during the filter initialization or
+when a command is processed
+
+- ‘frame’
+evaluate expressions for each incoming frame
+
+
+Default value is ‘init’.
+
+
+
+
+
39.188 phase
+
+
Delay interlaced video by one field time so that the field order changes.
+
+
The intended use is to fix PAL movies that have been captured with the
+opposite field order to the film-to-video transfer.
+
+
A description of the accepted parameters follows.
+
+
+- mode
+Set phase mode.
+
+It accepts the following values:
+
+- ‘t’
+Capture field order top-first, transfer bottom-first.
+Filter will delay the bottom field.
+
+- ‘b’
+Capture field order bottom-first, transfer top-first.
+Filter will delay the top field.
+
+- ‘p’
+Capture and transfer with the same field order. This mode only exists
+for the documentation of the other options to refer to, but if you
+actually select it, the filter will faithfully do nothing.
+
+- ‘a’
+Capture field order determined automatically by field flags, transfer
+opposite.
+Filter selects among ‘t’ and ‘b’ modes on a frame by frame
+basis using field flags. If no field information is available,
+then this works just like ‘u’.
+
+- ‘u’
+Capture unknown or varying, transfer opposite.
+Filter selects among ‘t’ and ‘b’ on a frame by frame basis by
+analyzing the images and selecting the alternative that produces best
+match between the fields.
+
+- ‘T’
+Capture top-first, transfer unknown or varying.
+Filter selects among ‘t’ and ‘p’ using image analysis.
+
+- ‘B’
+Capture bottom-first, transfer unknown or varying.
+Filter selects among ‘b’ and ‘p’ using image analysis.
+
+- ‘A’
+Capture determined by field flags, transfer unknown or varying.
+Filter selects among ‘t’, ‘b’ and ‘p’ using field flags and
+image analysis. If no field information is available, then this works just
+like ‘U’. This is the default mode.
+
+- ‘U’
+Both capture and transfer unknown or varying.
+Filter selects among ‘t’, ‘b’ and ‘p’ using image analysis only.
+
+
+
+
+
+
39.188.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.189 photosensitivity
+
Reduce various flashes in video, so to help users with epilepsy.
+
+
It accepts the following options:
+
+- frames, f
+Set how many frames to use when filtering. Default is 30.
+
+- threshold, t
+Set detection threshold factor. Default is 1.
+Lower is stricter.
+
+- skip
+Set how many pixels to skip when sampling frames. Default is 1.
+Allowed range is from 1 to 1024.
+
+- bypass
+Leave frames unchanged. Default is disabled.
+
+
+
+
+
39.190 pixdesctest
+
+
Pixel format descriptor test filter, mainly useful for internal
+testing. The output video should be equal to the input video.
+
+
For example:
+
+
format=monow, pixdesctest
+
+
+
can be used to test the monowhite pixel format descriptor definition.
+
+
+
+
39.191 pixelize
+
Apply pixelization to video stream.
+
+
The filter accepts the following options:
+
+- width, w
+- height, h
+Set block dimensions that will be used for pixelization.
+Default value is 16.
+
+- mode, m
+Set the mode of pixelization used.
+
+Possible values are:
+
+- ‘avg’
+- ‘min’
+- ‘max’
+
+Default value is avg.
+
+- planes, p
+Set what planes to filter. Default is to filter all planes.
+
+
+
+
+
39.191.1 Commands
+
+
This filter supports all options as commands.
+
+
+
+
+
39.192 pixscope
+
+
Display sample values of color channels. Mainly useful for checking color
+and levels. Minimum supported resolution is 640x480.
+
+
The filters accept the following options:
+
+
+- x
+Set scope X position, relative offset on X axis.
+
+- y
+Set scope Y position, relative offset on Y axis.
+
+- w
+Set scope width.
+
+- h
+Set scope height.
+
+- o
+Set window opacity. This window also holds statistics about pixel area.
+
+- wx
+Set window X position, relative offset on X axis.
+
+- wy
+Set window Y position, relative offset on Y axis.
+
+
+
+
+
39.192.1 Commands
+
+
This filter supports same commands as options.
+
+
+
+
+
39.193 pp
+
+
Enable the specified chain of postprocessing subfilters using libpostproc. This
+library should be automatically selected with a GPL build (--enable-gpl).
+Subfilters must be separated by ’/’ and can be disabled by prepending a ’-’.
+Each subfilter and some options have a short and a long name that can be used
+interchangeably, i.e. dr/dering are the same.
+
+
The filters accept the following options:
+
+
+- subfilters
+Set postprocessing subfilters string.
+
+
+
All subfilters share common options to determine their scope:
+
+
+- a/autoq
+Honor the quality commands for this subfilter.
+
+- c/chrom
+Do chrominance filtering, too (default).
+
+- y/nochrom
+Do luminance filtering only (no chrominance).
+
+- n/noluma
+Do chrominance filtering only (no luminance).
+
+
+
These options can be appended after the subfilter name, separated by a ’|’.
+
+
Available subfilters are:
+
+
+- hb/hdeblock[|difference[|flatness]]
+Horizontal deblocking filter
+
+- difference
+Difference factor where higher values mean more deblocking (default: 32).
+
- flatness
+Flatness threshold where lower values mean more deblocking (default: 39).
+
+
+- vb/vdeblock[|difference[|flatness]]
+Vertical deblocking filter
+
+- difference
+Difference factor where higher values mean more deblocking (default: 32).
+
- flatness
+Flatness threshold where lower values mean more deblocking (default: 39).
+
+
+- ha/hadeblock[|difference[|flatness]]
+Accurate horizontal deblocking filter
+
+- difference
+Difference factor where higher values mean more deblocking (default: 32).
+
- flatness
+Flatness threshold where lower values mean more deblocking (default: 39).
+
+
+- va/vadeblock[|difference[|flatness]]
+Accurate vertical deblocking filter
+
+- difference
+Difference factor where higher values mean more deblocking (default: 32).
+
- flatness
+Flatness threshold where lower values mean more deblocking (default: 39).
+
+
+
+
The horizontal and vertical deblocking filters share the difference and
+flatness values so you cannot set different horizontal and vertical
+thresholds.
+
+
+- h1/x1hdeblock
+Experimental horizontal deblocking filter
+
+- v1/x1vdeblock
+Experimental vertical deblocking filter
+
+- dr/dering
+Deringing filter
+
+- tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
+
+- threshold1
+larger -> stronger filtering
+
- threshold2
+larger -> stronger filtering
+
- threshold3
+larger -> stronger filtering
+
+
+- al/autolevels[:f/fullyrange], automatic brightness / contrast correction
+
+- f/fullyrange
+Stretch luminance to 0-255.
+
+
+- lb/linblenddeint
+Linear blend deinterlacing filter that deinterlaces the given block by
+filtering all lines with a (1 2 1) filter.
+
+- li/linipoldeint
+Linear interpolating deinterlacing filter that deinterlaces the given block by
+linearly interpolating every second line.
+
+- ci/cubicipoldeint
+Cubic interpolating deinterlacing filter deinterlaces the given block by
+cubically interpolating every second line.
+
+- md/mediandeint
+Median deinterlacing filter that deinterlaces the given block by applying a
+median filter to every second line.
+
+- fd/ffmpegdeint
+FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
+second line with a (-1 4 2 4 -1) filter.
+
+- l5/lowpass5
+Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
+block by filtering all lines with a (-1 2 6 2 -1) filter.
+
+- fq/forceQuant[|quantizer]
+Overrides the quantizer table from the input with the constant quantizer you
+specify.
+
+- quantizer
+Quantizer to use
+
+
+- de/default
+Default pp filter combination (hb|a,vb|a,dr|a)
+
+- fa/fast
+Fast pp filter combination (h1|a,v1|a,dr|a)
+
+- ac
+High quality pp filter combination (ha|a|128|7,va|a,dr|a)
+
+
+
+
+
39.193.1 Examples
+
+
+- Apply horizontal and vertical deblocking, deringing and automatic
+brightness/contrast:
+
+
+
- Apply default filters without brightness/contrast correction:
+
+
+
- Apply default filters and temporal denoiser:
+
+
pp=default/tmpnoise|1|2|3
+
- Apply deblocking on luminance only, and switch vertical deblocking on or off
+automatically depending on available CPU time:
+
+
+
+
+
+
+
39.194 pp7
+
Apply Postprocessing filter 7. It is variant of the spp filter,
+similar to spp = 6 with 7 point DCT, where only the center sample is
+used after IDCT.
+
+
The filter accepts the following options:
+
+
+- qp
+Force a constant quantization parameter. It accepts an integer in range
+0 to 63. If not set, the filter will use the QP from the video stream
+(if available).
+
+- mode
+Set thresholding mode. Available modes are:
+
+
+- ‘hard’
+Set hard thresholding.
+
- ‘soft’
+Set soft thresholding (better de-ringing effect, but likely blurrier).
+
- ‘medium’
+Set medium thresholding (good results, default).
+
+
+
+
+
+
39.195 premultiply
+
Apply alpha premultiply effect to input video stream using first plane
+of second stream as alpha.
+
+
Both streams must have same dimensions and same pixel format.
+
+
The filter accepts the following option:
+
+
+- planes
+Set which planes will be processed, unprocessed planes will be copied.
+By default value 0xf, all planes will be processed.
+
+- inplace
+Do not require 2nd input for processing, instead use alpha plane from input stream.
+
+
+
+
+
39.196 prewitt
+
Apply prewitt operator to input video stream.
+
+
The filter accepts the following option:
+
+
+- planes
+Set which planes will be processed, unprocessed planes will be copied.
+By default value 0xf, all planes will be processed.
+
+- scale
+Set value which will be multiplied with filtered result.
+
+- delta
+Set value which will be added to filtered result.
+
+
+
+
+
39.196.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.197 pseudocolor
+
+
Alter frame colors in video with pseudocolors.
+
+
This filter accepts the following options:
+
+
+- c0
+set pixel first component expression
+
+- c1
+set pixel second component expression
+
+- c2
+set pixel third component expression
+
+- c3
+set pixel fourth component expression, corresponds to the alpha component
+
+- index, i
+set component to use as base for altering colors
+
+- preset, p
+Pick one of built-in LUTs. By default is set to none.
+
+Available LUTs:
+
+- ‘magma’
+- ‘inferno’
+- ‘plasma’
+- ‘viridis’
+- ‘turbo’
+- ‘cividis’
+- ‘range1’
+- ‘range2’
+- ‘shadows’
+- ‘highlights’
+- ‘solar’
+- ‘nominal’
+- ‘preferred’
+- ‘total’
+- ‘spectral’
+
+
+- opacity
+Set opacity of output colors. Allowed range is from 0 to 1.
+Default value is set to 1.
+
+
+
Each of the expression options specifies the expression to use for computing
+the lookup table for the corresponding pixel component values.
+
+
The expressions can contain the following constants and functions:
+
+
+- w
+- h
+The input width and height.
+
+- val
+The input value for the pixel component.
+
+- ymin, umin, vmin, amin
+The minimum allowed component value.
+
+- ymax, umax, vmax, amax
+The maximum allowed component value.
+
+
+
All expressions default to "val".
+
+
+
+
39.197.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
39.197.2 Examples
+
+
+- Change too high luma values to gradient:
+
+
pseudocolor="'if(between(val,ymax,amax),lerp(ymin,ymax,(val-ymax)/(amax-ymax)),-1):if(between(val,ymax,amax),lerp(umax,umin,(val-ymax)/(amax-ymax)),-1):if(between(val,ymax,amax),lerp(vmin,vmax,(val-ymax)/(amax-ymax)),-1):-1'"
+
+
+
+
+
+
39.198 psnr
+
+
Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
+Ratio) between two input videos.
+
+
This filter takes in input two input videos, the first input is
+considered the "main" source and is passed unchanged to the
+output. The second input is used as a "reference" video for computing
+the PSNR.
+
+
Both video inputs must have the same resolution and pixel format for
+this filter to work correctly. Also it assumes that both inputs
+have the same number of frames, which are compared one by one.
+
+
The obtained average PSNR is printed through the logging system.
+
+
The filter stores the accumulated MSE (mean squared error) of each
+frame, and at the end of the processing it is averaged across all frames
+equally, and the following formula is applied to obtain the PSNR:
+
+
+
PSNR = 10*log10(MAX^2/MSE)
+
+
+
Where MAX is the average of the maximum values of each component of the
+image.
+
+
The description of the accepted parameters follows.
+
+
+- stats_file, f
+If specified the filter will use the named file to save the PSNR of
+each individual frame. When filename equals "-" the data is sent to
+standard output.
+
+- stats_version
+Specifies which version of the stats file format to use. Details of
+each format are written below.
+Default value is 1.
+
+- stats_add_max
+Determines whether the max value is output to the stats log.
+Default value is 0.
+Requires stats_version >= 2. If this is set and stats_version < 2,
+the filter will return an error.
+
+
+
This filter also supports the framesync options.
+
+
The file printed if stats_file is selected, contains a sequence of
+key/value pairs of the form key:value for each compared
+couple of frames.
+
+
If a stats_version greater than 1 is specified, a header line precedes
+the list of per-frame-pair stats, with key value pairs following the frame
+format with the following parameters:
+
+
+- psnr_log_version
+The version of the log file format. Will match stats_version.
+
+- fields
+A comma separated list of the per-frame-pair parameters included in
+the log.
+
+
+
A description of each shown per-frame-pair parameter follows:
+
+
+- n
+sequential number of the input frame, starting from 1
+
+- mse_avg
+Mean Square Error pixel-by-pixel average difference of the compared
+frames, averaged over all the image components.
+
+- mse_y, mse_u, mse_v, mse_r, mse_g, mse_b, mse_a
+Mean Square Error pixel-by-pixel average difference of the compared
+frames for the component specified by the suffix.
+
+- psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
+Peak Signal to Noise ratio of the compared frames for the component
+specified by the suffix.
+
+- max_avg, max_y, max_u, max_v
+Maximum allowed value for each channel, and average over all
+channels.
+
+
+
+
+
+
+
39.199 pullup
+
+
Pulldown reversal (inverse telecine) filter, capable of handling mixed
+hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
+content.
+
+
The pullup filter is designed to take advantage of future context in making
+its decisions. This filter is stateless in the sense that it does not lock
+onto a pattern to follow, but it instead looks forward to the following
+fields in order to identify matches and rebuild progressive frames.
+
+
To produce content with an even framerate, insert the fps filter after
+pullup, use fps=24000/1001 if the input frame rate is 29.97fps,
+fps=24 for 30fps and the (rare) telecined 25fps input.
+
+
The filter accepts the following options:
+
+
+- jl
+- jr
+- jt
+- jb
+These options set the amount of "junk" to ignore at the left, right, top, and
+bottom of the image, respectively. Left and right are in units of 8 pixels,
+while top and bottom are in units of 2 lines.
+The default is 8 pixels on each side.
+
+- sb
+Set the strict breaks. Setting this option to 1 will reduce the chances of
+filter generating an occasional mismatched frame, but it may also cause an
+excessive number of frames to be dropped during high motion sequences.
+Conversely, setting it to -1 will make filter match fields more easily.
+This may help processing of video where there is slight blurring between
+the fields, but may also cause there to be interlaced frames in the output.
+Default value is 0.
+
+- mp
+Set the metric plane to use. It accepts the following values:
+
+- ‘l’
+Use luma plane.
+
+- ‘u’
+Use chroma blue plane.
+
+- ‘v’
+Use chroma red plane.
+
+
+This option may be set to use chroma plane instead of the default luma plane
+for doing filter’s computations. This may improve accuracy on very clean
+source material, but more likely will decrease accuracy, especially if there
+is chroma noise (rainbow effect) or any grayscale video.
+The main purpose of setting mp to a chroma plane is to reduce CPU
+load and make pullup usable in realtime on slow machines.
+
+
+
For best results (without duplicated frames in the output file) it is
+necessary to change the output frame rate. For example, to inverse
+telecine NTSC input:
+
+
ffmpeg -i input -vf pullup -r 24000/1001 ...
+
+
+
+
+
39.200 qp
+
+
Change video quantization parameters (QP).
+
+
The filter accepts the following option:
+
+
+- qp
+Set expression for quantization parameter.
+
+
+
The expression is evaluated through the eval API and can contain, among others,
+the following constants:
+
+
+- known
+1 if index is not 129, 0 otherwise.
+
+- qp
+Sequential index starting from -129 to 128.
+
+
+
+
+
39.200.1 Examples
+
+
+
+
+
+
+
39.201 random
+
+
Flush video frames from internal cache of frames into a random order.
+No frame is discarded.
+Inspired by frei0r nervous filter.
+
+
+- frames
+Set size in number of frames of internal cache, in range from 2 to
+512. Default is 30.
+
+- seed
+Set seed for random number generator, must be an integer included between
+0 and UINT32_MAX. If not specified, or if explicitly set to
+less than 0, the filter will try to use a good random seed on a
+best effort basis.
+
+
+
+
+
39.202 readeia608
+
+
Read closed captioning (EIA-608) information from the top lines of a video frame.
+
+
This filter adds frame metadata for lavfi.readeia608.X.cc and
+lavfi.readeia608.X.line, where X is the number of the identified line
+with EIA-608 data (starting from 0). A description of each metadata value follows:
+
+
+- lavfi.readeia608.X.cc
+The two bytes stored as EIA-608 data (printed in hexadecimal).
+
+- lavfi.readeia608.X.line
+The number of the line on which the EIA-608 data was identified and read.
+
+
+
This filter accepts the following options:
+
+
+- scan_min
+Set the line to start scanning for EIA-608 data. Default is 0.
+
+- scan_max
+Set the line to end scanning for EIA-608 data. Default is 29.
+
+- spw
+Set the ratio of width reserved for sync code detection.
+Default is 0.27. Allowed range is [0.1 - 0.7].
+
+- chp
+Enable checking the parity bit. In the event of a parity error, the filter will output
+0x00 for that character. Default is false.
+
+- lp
+Lowpass lines prior to further processing. Default is enabled.
+
+
+
+
+
39.202.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
39.202.2 Examples
+
+
+- Output a csv with presentation time and the first two lines of identified EIA-608 captioning data.
+
+
ffprobe -f lavfi -i movie=captioned_video.mov,readeia608 -show_entries frame=pts_time:frame_tags=lavfi.readeia608.0.cc,lavfi.readeia608.1.cc -of csv
+
+
+
+
+
+
39.203 readvitc
+
+
Read vertical interval timecode (VITC) information from the top lines of a
+video frame.
+
+
The filter adds frame metadata key lavfi.readvitc.tc_str with the
+timecode value, if a valid timecode has been detected. Further metadata key
+lavfi.readvitc.found is set to 0/1 depending on whether
+timecode data has been found or not.
+
+
This filter accepts the following options:
+
+
+- scan_max
+Set the maximum number of lines to scan for VITC data. If the value is set to
+-1 the full video frame is scanned. Default is 45.
+
+- thr_b
+Set the luma threshold for black. Accepts float numbers in the range [0.0,1.0],
+default value is 0.2. The value must be equal or less than thr_w.
+
+- thr_w
+Set the luma threshold for white. Accepts float numbers in the range [0.0,1.0],
+default value is 0.6. The value must be equal or greater than thr_b.
+
+
+
+
+
39.203.1 Examples
+
+
+- Detect and draw VITC data onto the video frame; if no valid VITC is detected,
+draw
--:--:--:-- as a placeholder:
+
+
ffmpeg -i input.avi -filter:v 'readvitc,drawtext=fontfile=FreeMono.ttf:text=%{metadata\\:lavfi.readvitc.tc_str\\:--\\\\\\:--\\\\\\:--\\\\\\:--}:x=(w-tw)/2:y=400-ascent'
+
+
+
+
+
+
39.204 remap
+
+
Remap pixels using 2nd: Xmap and 3rd: Ymap input video stream.
+
+
Destination pixel at position (X, Y) will be picked from source (x, y) position
+where x = Xmap(X, Y) and y = Ymap(X, Y). If mapping values are out of range, zero
+value for pixel will be used for destination pixel.
+
+
Xmap and Ymap input video streams must be of same dimensions. Output video stream
+will have Xmap/Ymap video stream dimensions.
+Xmap and Ymap input video streams are 16bit depth, single channel.
+
+
+- format
+Specify pixel format of output from this filter. Can be color or gray.
+Default is color.
+
+- fill
+Specify the color of the unmapped pixels. For the syntax of this option,
+check the (ffmpeg-utils)"Color" section in the ffmpeg-utils
+manual. Default color is black.
+
+
+
+
+
39.205 removegrain
+
+
The removegrain filter is a spatial denoiser for progressive video.
+
+
+- m0
+Set mode for the first plane.
+
+- m1
+Set mode for the second plane.
+
+- m2
+Set mode for the third plane.
+
+- m3
+Set mode for the fourth plane.
+
+
+
Range of mode is from 0 to 24. Description of each mode follows:
+
+
+- 0
+Leave input plane unchanged. Default.
+
+- 1
+Clips the pixel with the minimum and maximum of the 8 neighbour pixels.
+
+- 2
+Clips the pixel with the second minimum and maximum of the 8 neighbour pixels.
+
+- 3
+Clips the pixel with the third minimum and maximum of the 8 neighbour pixels.
+
+- 4
+Clips the pixel with the fourth minimum and maximum of the 8 neighbour pixels.
+This is equivalent to a median filter.
+
+- 5
+Line-sensitive clipping giving the minimal change.
+
+- 6
+Line-sensitive clipping, intermediate.
+
+- 7
+Line-sensitive clipping, intermediate.
+
+- 8
+Line-sensitive clipping, intermediate.
+
+- 9
+Line-sensitive clipping on a line where the neighbours pixels are the closest.
+
+- 10
+Replaces the target pixel with the closest neighbour.
+
+- 11
+[1 2 1] horizontal and vertical kernel blur.
+
+- 12
+Same as mode 11.
+
+- 13
+Bob mode, interpolates top field from the line where the neighbours
+pixels are the closest.
+
+- 14
+Bob mode, interpolates bottom field from the line where the neighbours
+pixels are the closest.
+
+- 15
+Bob mode, interpolates top field. Same as 13 but with a more complicated
+interpolation formula.
+
+- 16
+Bob mode, interpolates bottom field. Same as 14 but with a more complicated
+interpolation formula.
+
+- 17
+Clips the pixel with the minimum and maximum of respectively the maximum and
+minimum of each pair of opposite neighbour pixels.
+
+- 18
+Line-sensitive clipping using opposite neighbours whose greatest distance from
+the current pixel is minimal.
+
+- 19
+Replaces the pixel with the average of its 8 neighbours.
+
+- 20
+Averages the 9 pixels ([1 1 1] horizontal and vertical blur).
+
+- 21
+Clips pixels using the averages of opposite neighbour.
+
+- 22
+Same as mode 21 but simpler and faster.
+
+- 23
+Small edge and halo removal, but reputed useless.
+
+- 24
+Similar as 23.
+
+
+
+
+
39.206 removelogo
+
+
Suppress a TV station logo, using an image file to determine which
+pixels comprise the logo. It works by filling in the pixels that
+comprise the logo with neighboring pixels.
+
+
The filter accepts the following options:
+
+
+- filename, f
+Set the filter bitmap file, which can be any image format supported by
+libavformat. The width and height of the image file must match those of the
+video stream being processed.
+
+
+
Pixels in the provided bitmap image with a value of zero are not
+considered part of the logo, non-zero pixels are considered part of
+the logo. If you use white (255) for the logo and black (0) for the
+rest, you will be safe. For making the filter bitmap, it is
+recommended to take a screen capture of a black frame with the logo
+visible, and then using a threshold filter followed by the erode
+filter once or twice.
+
+
If needed, little splotches can be fixed manually. Remember that if
+logo pixels are not covered, the filter quality will be much
+reduced. Marking too many pixels as part of the logo does not hurt as
+much, but it will increase the amount of blurring needed to cover over
+the image and will destroy more information than necessary, and extra
+pixels will slow things down on a large logo.
+
+
+
+
39.207 repeatfields
+
+
This filter uses the repeat_field flag from the Video ES headers and hard repeats
+fields based on its value.
+
+
+
+
39.208 reverse
+
+
Reverse a video clip.
+
+
Warning: This filter requires memory to buffer the entire clip, so trimming
+is suggested.
+
+
+
+
39.208.1 Examples
+
+
+- Take the first 5 seconds of a clip, and reverse it.
+
+
+
+
+
+
+
39.209 rgbashift
+
Shift R/G/B/A pixels horizontally and/or vertically.
+
+
The filter accepts the following options:
+
+- rh
+Set amount to shift red horizontally.
+
- rv
+Set amount to shift red vertically.
+
- gh
+Set amount to shift green horizontally.
+
- gv
+Set amount to shift green vertically.
+
- bh
+Set amount to shift blue horizontally.
+
- bv
+Set amount to shift blue vertically.
+
- ah
+Set amount to shift alpha horizontally.
+
- av
+Set amount to shift alpha vertically.
+
- edge
+Set edge mode, can be smear, default, or warp.
+
+
+
+
+
39.209.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.210 roberts
+
Apply roberts cross operator to input video stream.
+
+
The filter accepts the following option:
+
+
+- planes
+Set which planes will be processed, unprocessed planes will be copied.
+By default value 0xf, all planes will be processed.
+
+- scale
+Set value which will be multiplied with filtered result.
+
+- delta
+Set value which will be added to filtered result.
+
+
+
+
+
39.210.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.211 rotate
+
+
Rotate video by an arbitrary angle expressed in radians.
+
+
The filter accepts the following options:
+
+
A description of the optional parameters follows.
+
+- angle, a
+Set an expression for the angle by which to rotate the input video
+clockwise, expressed as a number of radians. A negative value will
+result in a counter-clockwise rotation. By default it is set to "0".
+
+This expression is evaluated for each frame.
+
+- out_w, ow
+Set the output width expression, default value is "iw".
+This expression is evaluated just once during configuration.
+
+- out_h, oh
+Set the output height expression, default value is "ih".
+This expression is evaluated just once during configuration.
+
+- bilinear
+Enable bilinear interpolation if set to 1, a value of 0 disables
+it. Default value is 1.
+
+- fillcolor, c
+Set the color used to fill the output area not covered by the rotated
+image. For the general syntax of this option, check the
+(ffmpeg-utils)"Color" section in the ffmpeg-utils manual.
+If the special value "none" is selected then no
+background is printed (useful for example if the background is never shown).
+
+Default value is "black".
+
+
+
The expressions for the angle and the output size can contain the
+following constants and functions:
+
+
+- n
+sequential number of the input frame, starting from 0. It is always NAN
+before the first frame is filtered.
+
+- t
+time in seconds of the input frame, it is set to 0 when the filter is
+configured. It is always NAN before the first frame is filtered.
+
+- hsub
+- vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" hsub is 2 and vsub is 1.
+
+- in_w, iw
+- in_h, ih
+the input video width and height
+
+- out_w, ow
+- out_h, oh
+the output width and height, that is the size of the padded area as
+specified by the width and height expressions
+
+- rotw(a)
+- roth(a)
+the minimal width/height required for completely containing the input
+video rotated by a radians.
+
+These are only available when computing the out_w and
+out_h expressions.
+
+
+
+
+
39.211.1 Examples
+
+
+- Rotate the input by PI/6 radians clockwise:
+
+
+
- Rotate the input by PI/6 radians counter-clockwise:
+
+
+
- Rotate the input by 45 degrees clockwise:
+
+
+
- Apply a constant rotation with period T, starting from an angle of PI/3:
+
+
+
- Make the input video rotation oscillating with a period of T
+seconds and an amplitude of A radians:
+
+
rotate=A*sin(2*PI/T*t)
+
- Rotate the video, output size is chosen so that the whole rotating
+input video is always completely contained in the output:
+
+
rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
+
- Rotate the video, reduce the output size so that no background is ever
+shown:
+
+
rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
+
+
+
+
+
39.211.2 Commands
+
+
The filter supports the following commands:
+
+
+- a, angle
+Set the angle expression.
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
+
39.212 sab
+
+
Apply Shape Adaptive Blur.
+
+
The filter accepts the following options:
+
+
+- luma_radius, lr
+Set luma blur filter strength, must be a value in range 0.1-4.0, default
+value is 1.0. A greater value will result in a more blurred image, and
+in slower processing.
+
+- luma_pre_filter_radius, lpfr
+Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
+value is 1.0.
+
+- luma_strength, ls
+Set luma maximum difference between pixels to still be considered, must
+be a value in the 0.1-100.0 range, default value is 1.0.
+
+- chroma_radius, cr
+Set chroma blur filter strength, must be a value in range -0.9-4.0. A
+greater value will result in a more blurred image, and in slower
+processing.
+
+- chroma_pre_filter_radius, cpfr
+Set chroma pre-filter radius, must be a value in the -0.9-2.0 range.
+
+- chroma_strength, cs
+Set chroma maximum difference between pixels to still be considered,
+must be a value in the -0.9-100.0 range.
+
+
+
Each chroma option value, if not explicitly specified, is set to the
+corresponding luma option value.
+
+
+
+
39.213 scale
+
+
Scale (resize) the input video, using the libswscale library.
+
+
The scale filter forces the output display aspect ratio to be the same
+of the input, by changing the output sample aspect ratio.
+
+
If the input image format is different from the format requested by
+the next filter, the scale filter will convert the input to the
+requested format.
+
+
+
+
39.213.1 Options
+
The filter accepts the following options, or any of the options
+supported by the libswscale scaler.
+
+
See (ffmpeg-scaler)the ffmpeg-scaler manual for
+the complete list of scaler options.
+
+
+- width, w
+- height, h
+Set the output video dimension expression. Default value is the input
+dimension.
+
+If the width or w value is 0, the input width is used for
+the output. If the height or h value is 0, the input height
+is used for the output.
+
+If one and only one of the values is -n with n >= 1, the scale filter
+will use a value that maintains the aspect ratio of the input image,
+calculated from the other specified dimension. After that it will,
+however, make sure that the calculated dimension is divisible by n and
+adjust the value if necessary.
+
+If both values are -n with n >= 1, the behavior will be identical to
+both values being set to 0 as previously detailed.
+
+See below for the list of accepted constants for use in the dimension
+expression.
+
+- eval
+Specify when to evaluate width and height expression. It accepts the following values:
+
+
+- ‘init’
+Only evaluate expressions once during the filter initialization or when a command is processed.
+
+- ‘frame’
+Evaluate expressions for each incoming frame.
+
+
+
+Default value is ‘init’.
+
+
+- interl
+Set the interlacing mode. It accepts the following values:
+
+
+- ‘1’
+Force interlaced aware scaling.
+
+- ‘0’
+Do not apply interlaced scaling.
+
+- ‘-1’
+Select interlaced aware scaling depending on whether the source frames
+are flagged as interlaced or not.
+
+
+Default value is ‘0’.
+
+- flags
+Set libswscale scaling flags. See
+(ffmpeg-scaler)the ffmpeg-scaler manual for the
+complete list of values. If not explicitly specified the filter applies
+the default flags.
+
+
+- param0, param1
+Set libswscale input parameters for scaling algorithms that need them. See
+(ffmpeg-scaler)the ffmpeg-scaler manual for the
+complete documentation. If not explicitly specified the filter applies
+empty parameters.
+
+
+
+- size, s
+Set the video size. For the syntax of this option, check the
+(ffmpeg-utils)"Video size" section in the ffmpeg-utils manual.
+
+- in_color_matrix
+- out_color_matrix
+Set in/output YCbCr color space type.
+
+This allows the autodetected value to be overridden as well as allows forcing
+a specific value used for the output and encoder.
+
+If not specified, the color space type depends on the pixel format.
+
+Possible values:
+
+
+- ‘auto’
+Choose automatically.
+
+- ‘bt709’
+Format conforming to International Telecommunication Union (ITU)
+Recommendation BT.709.
+
+- ‘fcc’
+Set color space conforming to the United States Federal Communications
+Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
+
+- ‘bt601’
+- ‘bt470’
+- ‘smpte170m’
+Set color space conforming to:
+
+
+- ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
+
+
- ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
+
+
- Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
+
+
+
+- ‘smpte240m’
+Set color space conforming to SMPTE ST 240:1999.
+
+- ‘bt2020’
+Set color space conforming to ITU-R BT.2020 non-constant luminance system.
+
+
+- in_range
+- out_range
+Set in/output YCbCr sample range.
+
+This allows the autodetected value to be overridden as well as allows forcing
+a specific value used for the output and encoder. If not specified, the
+range depends on the pixel format. Possible values:
+
+
+- ‘auto/unknown’
+Choose automatically.
+
+- ‘jpeg/full/pc’
+Set full range (0-255 in case of 8-bit luma).
+
+- ‘mpeg/limited/tv’
+Set "MPEG" range (16-235 in case of 8-bit luma).
+
+
+- force_original_aspect_ratio
+Enable decreasing or increasing output video width or height if necessary to
+keep the original aspect ratio. Possible values:
+
+
+- ‘disable’
+Scale the video as specified and disable this feature.
+
+- ‘decrease’
+The output video dimensions will automatically be decreased if needed.
+
+- ‘increase’
+The output video dimensions will automatically be increased if needed.
+
+
+
+One useful instance of this option is that when you know a specific device’s
+maximum allowed resolution, you can use this to limit the output video to
+that, while retaining the aspect ratio. For example, device A allows
+1280x720 playback, and your video is 1920x800. Using this option (set it to
+decrease) and specifying 1280x720 to the command line makes the output
+1280x533.
+
+Please note that this is a different thing than specifying -1 for w
+or h, you still need to specify the output resolution for this option
+to work.
+
+- force_divisible_by
+Ensures that both the output dimensions, width and height, are divisible by the
+given integer when used together with force_original_aspect_ratio. This
+works similar to using -n in the w and h options.
+
+This option respects the value set for force_original_aspect_ratio,
+increasing or decreasing the resolution accordingly. The video’s aspect ratio
+may be slightly modified.
+
+This option can be handy if you need to have a video fit within or exceed
+a defined resolution using force_original_aspect_ratio but also have
+encoder restrictions on width or height divisibility.
+
+
+
+
The values of the w and h options are expressions
+containing the following constants:
+
+
+- in_w
+- in_h
+The input width and height
+
+- iw
+- ih
+These are the same as in_w and in_h.
+
+- out_w
+- out_h
+The output (scaled) width and height
+
+- ow
+- oh
+These are the same as out_w and out_h
+
+- a
+The same as iw / ih
+
+- sar
+input sample aspect ratio
+
+- dar
+The input display aspect ratio. Calculated from (iw / ih) * sar.
+
+- hsub
+- vsub
+horizontal and vertical input chroma subsample values. For example for the
+pixel format "yuv422p" hsub is 2 and vsub is 1.
+
+- ohsub
+- ovsub
+horizontal and vertical output chroma subsample values. For example for the
+pixel format "yuv422p" hsub is 2 and vsub is 1.
+
+- n
+The (sequential) number of the input frame, starting from 0.
+Only available with eval=frame.
+
+- t
+The presentation timestamp of the input frame, expressed as a number of
+seconds. Only available with eval=frame.
+
+- pos
+The position (byte offset) of the frame in the input stream, or NaN if
+this information is unavailable and/or meaningless (for example in case of synthetic video).
+Only available with eval=frame.
+Deprecated, do not use.
+
+
+
+
+
39.213.2 Examples
+
+
+
+
+
+
39.213.3 Commands
+
+
This filter supports the following commands:
+
+- width, w
+- height, h
+Set the output video dimension expression.
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
+
39.214 scale_cuda
+
+
Scale (resize) and convert (pixel format) the input video, using accelerated CUDA kernels.
+Setting the output width and height works in the same way as for the scale filter.
+
+
The filter accepts the following options:
+
+- w
+- h
+Set the output video dimension expression. Default value is the input dimension.
+
+Allows for the same expressions as the scale filter.
+
+- interp_algo
+Sets the algorithm used for scaling:
+
+
+- nearest
+Nearest neighbour
+
+Used by default if input parameters match the desired output.
+
+- bilinear
+Bilinear
+
+- bicubic
+Bicubic
+
+This is the default.
+
+- lanczos
+Lanczos
+
+
+
+- format
+Controls the output pixel format. By default, or if none is specified, the input
+pixel format is used.
+
+The filter does not support converting between YUV and RGB pixel formats.
+
+- passthrough
+If set to 0, every frame is processed, even if no conversion is neccesary.
+This mode can be useful to use the filter as a buffer for a downstream
+frame-consumer that exhausts the limited decoder frame pool.
+
+If set to 1, frames are passed through as-is if they match the desired output
+parameters. This is the default behaviour.
+
+- param
+Algorithm-Specific parameter.
+
+Affects the curves of the bicubic algorithm.
+
+- force_original_aspect_ratio
+- force_divisible_by
+Work the same as the identical scale filter options.
+
+
+
+
+
+
39.214.1 Examples
+
+
+- Scale input to 720p, keeping aspect ratio and ensuring the output is yuv420p.
+
+
scale_cuda=-2:720:format=yuv420p
+
- Upscale to 4K using nearest neighbour algorithm.
+
+
scale_cuda=4096:2160:interp_algo=nearest
+
- Don’t do any conversion or scaling, but copy all input frames into newly allocated ones.
+This can be useful to deal with a filter and encode chain that otherwise exhausts the
+decoders frame pool.
+
+
scale_cuda=passthrough=0
+
+
+
+
+
+
39.215 scale_npp
+
+
Use the NVIDIA Performance Primitives (libnpp) to perform scaling and/or pixel
+format conversion on CUDA video frames. Setting the output width and height
+works in the same way as for the scale filter.
+
+
The following additional options are accepted:
+
+- format
+The pixel format of the output CUDA frames. If set to the string "same" (the
+default), the input format will be kept. Note that automatic format negotiation
+and conversion is not yet supported for hardware frames
+
+- interp_algo
+The interpolation algorithm used for resizing. One of the following:
+
+- nn
+Nearest neighbour.
+
+- linear
+- cubic
+- cubic2p_bspline
+2-parameter cubic (B=1, C=0)
+
+- cubic2p_catmullrom
+2-parameter cubic (B=0, C=1/2)
+
+- cubic2p_b05c03
+2-parameter cubic (B=1/2, C=3/10)
+
+- super
+Supersampling
+
+- lanczos
+
+
+- force_original_aspect_ratio
+Enable decreasing or increasing output video width or height if necessary to
+keep the original aspect ratio. Possible values:
+
+
+- ‘disable’
+Scale the video as specified and disable this feature.
+
+- ‘decrease’
+The output video dimensions will automatically be decreased if needed.
+
+- ‘increase’
+The output video dimensions will automatically be increased if needed.
+
+
+
+One useful instance of this option is that when you know a specific device’s
+maximum allowed resolution, you can use this to limit the output video to
+that, while retaining the aspect ratio. For example, device A allows
+1280x720 playback, and your video is 1920x800. Using this option (set it to
+decrease) and specifying 1280x720 to the command line makes the output
+1280x533.
+
+Please note that this is a different thing than specifying -1 for w
+or h, you still need to specify the output resolution for this option
+to work.
+
+- force_divisible_by
+Ensures that both the output dimensions, width and height, are divisible by the
+given integer when used together with force_original_aspect_ratio. This
+works similar to using -n in the w and h options.
+
+This option respects the value set for force_original_aspect_ratio,
+increasing or decreasing the resolution accordingly. The video’s aspect ratio
+may be slightly modified.
+
+This option can be handy if you need to have a video fit within or exceed
+a defined resolution using force_original_aspect_ratio but also have
+encoder restrictions on width or height divisibility.
+
+- eval
+Specify when to evaluate width and height expression. It accepts the following values:
+
+
+- ‘init’
+Only evaluate expressions once during the filter initialization or when a command is processed.
+
+- ‘frame’
+Evaluate expressions for each incoming frame.
+
+
+
+
+
+
The values of the w and h options are expressions
+containing the following constants:
+
+
+- in_w
+- in_h
+The input width and height
+
+- iw
+- ih
+These are the same as in_w and in_h.
+
+- out_w
+- out_h
+The output (scaled) width and height
+
+- ow
+- oh
+These are the same as out_w and out_h
+
+- a
+The same as iw / ih
+
+- sar
+input sample aspect ratio
+
+- dar
+The input display aspect ratio. Calculated from (iw / ih) * sar.
+
+- n
+The (sequential) number of the input frame, starting from 0.
+Only available with eval=frame.
+
+- t
+The presentation timestamp of the input frame, expressed as a number of
+seconds. Only available with eval=frame.
+
+- pos
+The position (byte offset) of the frame in the input stream, or NaN if
+this information is unavailable and/or meaningless (for example in case of synthetic video).
+Only available with eval=frame.
+Deprecated, do not use.
+
+
+
+
+
39.216 scale2ref
+
+
Scale (resize) the input video, based on a reference video.
+
+
See the scale filter for available options, scale2ref supports the same but
+uses the reference video instead of the main input as basis. scale2ref also
+supports the following additional constants for the w and
+h options:
+
+
+- main_w
+- main_h
+The main input video’s width and height
+
+- main_a
+The same as main_w / main_h
+
+- main_sar
+The main input video’s sample aspect ratio
+
+- main_dar, mdar
+The main input video’s display aspect ratio. Calculated from
+(main_w / main_h) * main_sar.
+
+- main_hsub
+- main_vsub
+The main input video’s horizontal and vertical chroma subsample values.
+For example for the pixel format "yuv422p" hsub is 2 and vsub
+is 1.
+
+- main_n
+The (sequential) number of the main input frame, starting from 0.
+Only available with eval=frame.
+
+- main_t
+The presentation timestamp of the main input frame, expressed as a number of
+seconds. Only available with eval=frame.
+
+- main_pos
+The position (byte offset) of the frame in the main input stream, or NaN if
+this information is unavailable and/or meaningless (for example in case of synthetic video).
+Only available with eval=frame.
+
+
+
+
+
39.216.1 Examples
+
+
+- Scale a subtitle stream (b) to match the main video (a) in size before overlaying
+
+
'scale2ref[b][a];[a][b]overlay'
+
- Scale a logo to 1/10th the height of a video, while preserving its display aspect ratio.
+
+
[logo-in][video-in]scale2ref=w=oh*mdar:h=ih/10[logo-out][video-out]
+
+
+
+
+
39.216.2 Commands
+
+
This filter supports the following commands:
+
+- width, w
+- height, h
+Set the output video dimension expression.
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
+
39.217 scale2ref_npp
+
+
Use the NVIDIA Performance Primitives (libnpp) to scale (resize) the input
+video, based on a reference video.
+
+
See the scale_npp filter for available options, scale2ref_npp supports the same
+but uses the reference video instead of the main input as basis. scale2ref_npp
+also supports the following additional constants for the w and
+h options:
+
+
+- main_w
+- main_h
+The main input video’s width and height
+
+- main_a
+The same as main_w / main_h
+
+- main_sar
+The main input video’s sample aspect ratio
+
+- main_dar, mdar
+The main input video’s display aspect ratio. Calculated from
+(main_w / main_h) * main_sar.
+
+- main_n
+The (sequential) number of the main input frame, starting from 0.
+Only available with eval=frame.
+
+- main_t
+The presentation timestamp of the main input frame, expressed as a number of
+seconds. Only available with eval=frame.
+
+- main_pos
+The position (byte offset) of the frame in the main input stream, or NaN if
+this information is unavailable and/or meaningless (for example in case of synthetic video).
+Only available with eval=frame.
+
+
+
+
+
39.217.1 Examples
+
+
+- Scale a subtitle stream (b) to match the main video (a) in size before overlaying
+
+
'scale2ref_npp[b][a];[a][b]overlay_cuda'
+
- Scale a logo to 1/10th the height of a video, while preserving its display aspect ratio.
+
+
[logo-in][video-in]scale2ref_npp=w=oh*mdar:h=ih/10[logo-out][video-out]
+
+
+
+
+
+
39.218 scharr
+
Apply scharr operator to input video stream.
+
+
The filter accepts the following option:
+
+
+- planes
+Set which planes will be processed, unprocessed planes will be copied.
+By default value 0xf, all planes will be processed.
+
+- scale
+Set value which will be multiplied with filtered result.
+
+- delta
+Set value which will be added to filtered result.
+
+
+
+
+
39.218.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
+
39.220 scdet
+
+
Detect video scene change.
+
+
This filter sets frame metadata with mafd between frame, the scene score, and
+forward the frame to the next filter, so they can use these metadata to detect
+scene change or others.
+
+
In addition, this filter logs a message and sets frame metadata when it detects
+a scene change by threshold.
+
+
lavfi.scd.mafd metadata keys are set with mafd for every frame.
+
+
lavfi.scd.score metadata keys are set with scene change score for every frame
+to detect scene change.
+
+
lavfi.scd.time metadata keys are set with current filtered frame time which
+detect scene change with threshold.
+
+
The filter accepts the following options:
+
+
+- threshold, t
+Set the scene change detection threshold as a percentage of maximum change. Good
+values are in the [8.0, 14.0] range. The range for threshold is
+[0., 100.].
+
+Default value is 10..
+
+- sc_pass, s
+Set the flag to pass scene change frames to the next filter. Default value is 0
+You can enable it if you want to get snapshot of scene change frames only.
+
+
+
+
+
39.221 selectivecolor
+
+
Adjust cyan, magenta, yellow and black (CMYK) to certain ranges of colors (such
+as "reds", "yellows", "greens", "cyans", ...). The adjustment range is defined
+by the "purity" of the color (that is, how saturated it already is).
+
+
This filter is similar to the Adobe Photoshop Selective Color tool.
+
+
The filter accepts the following options:
+
+
+- correction_method
+Select color correction method.
+
+Available values are:
+
+- ‘absolute’
+Specified adjustments are applied "as-is" (added/subtracted to original pixel
+component value).
+
- ‘relative’
+Specified adjustments are relative to the original component value.
+
+Default is absolute.
+
- reds
+Adjustments for red pixels (pixels where the red component is the maximum)
+
- yellows
+Adjustments for yellow pixels (pixels where the blue component is the minimum)
+
- greens
+Adjustments for green pixels (pixels where the green component is the maximum)
+
- cyans
+Adjustments for cyan pixels (pixels where the red component is the minimum)
+
- blues
+Adjustments for blue pixels (pixels where the blue component is the maximum)
+
- magentas
+Adjustments for magenta pixels (pixels where the green component is the minimum)
+
- whites
+Adjustments for white pixels (pixels where all components are greater than 128)
+
- neutrals
+Adjustments for all pixels except pure black and pure white
+
- blacks
+Adjustments for black pixels (pixels where all components are lesser than 128)
+
- psfile
+Specify a Photoshop selective color file (.asv) to import the settings from.
+
+
+
All the adjustment settings (reds, yellows, ...) accept up to
+4 space separated floating point adjustment values in the [-1,1] range,
+respectively to adjust the amount of cyan, magenta, yellow and black for the
+pixels of its range.
+
+
+
+
39.221.1 Examples
+
+
+- Increase cyan by 50% and reduce yellow by 33% in every green areas, and
+increase magenta by 27% in blue areas:
+
+
selectivecolor=greens=.5 0 -.33 0:blues=0 .27
+
- Use a Photoshop selective color preset:
+
+
selectivecolor=psfile=MySelectiveColorPresets/Misty.asv
+
+
+
+
+
+
39.222 separatefields
+
+
The separatefields takes a frame-based video input and splits
+each frame into its components fields, producing a new half height clip
+with twice the frame rate and twice the frame count.
+
+
This filter use field-dominance information in frame to decide which
+of each pair of fields to place first in the output.
+If it gets it wrong use setfield filter before separatefields filter.
+
+
+
+
39.223 setdar, setsar
+
+
The setdar filter sets the Display Aspect Ratio for the filter
+output video.
+
+
This is done by changing the specified Sample (aka Pixel) Aspect
+Ratio, according to the following equation:
+
+
DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR
+
+
+
Keep in mind that the setdar filter does not modify the pixel
+dimensions of the video frame. Also, the display aspect ratio set by
+this filter may be changed by later filters in the filterchain,
+e.g. in case of scaling or if another "setdar" or a "setsar" filter is
+applied.
+
+
The setsar filter sets the Sample (aka Pixel) Aspect Ratio for
+the filter output video.
+
+
Note that as a consequence of the application of this filter, the
+output display aspect ratio will change according to the equation
+above.
+
+
Keep in mind that the sample aspect ratio set by the setsar
+filter may be changed by later filters in the filterchain, e.g. if
+another "setsar" or a "setdar" filter is applied.
+
+
It accepts the following parameters:
+
+
+- r, ratio, dar (
setdar only), sar (setsar only)
+Set the aspect ratio used by the filter.
+
+The parameter can be a floating point number string, or an expression. If the
+parameter is not specified, the value "0" is assumed, meaning that the same
+input value is used.
+
+- max
+Set the maximum integer value to use for expressing numerator and
+denominator when reducing the expressed aspect ratio to a rational.
+Default value is 100.
+
+
+
+
The parameter sar is an expression containing the following constants:
+
+
+- w, h
+The input width and height.
+
+- a
+Same as w / h.
+
+- sar
+The input sample aspect ratio.
+
+- dar
+The input display aspect ratio. It is the same as
+(w / h) * sar.
+
+- hsub, vsub
+Horizontal and vertical chroma subsample values. For example, for the
+pixel format "yuv422p" hsub is 2 and vsub is 1.
+
+
+
+
+
39.223.1 Examples
+
+
+- To change the display aspect ratio to 16:9, specify one of the following:
+
+
setdar=dar=1.77777
+setdar=dar=16/9
+
- To change the sample aspect ratio to 10:11, specify:
+
+
+
- To set a display aspect ratio of 16:9, and specify a maximum integer value of
+1000 in the aspect ratio reduction, use the command:
+
+
setdar=ratio=16/9:max=1000
+
+
+
+
+
+
39.224 setfield
+
+
Force field for the output video frame.
+
+
The setfield filter marks the interlace type field for the
+output frames. It does not change the input frame, but only sets the
+corresponding property, which affects how the frame is treated by
+following filters (e.g. fieldorder or yadif).
+
+
The filter accepts the following options:
+
+
+- mode
+Available values are:
+
+
+- ‘auto’
+Keep the same field property.
+
+- ‘bff’
+Mark the frame as bottom-field-first.
+
+- ‘tff’
+Mark the frame as top-field-first.
+
+- ‘prog’
+Mark the frame as progressive.
+
+
+
+
+
+
39.225 setparams
+
+
Force frame parameter for the output video frame.
+
+
The setparams filter marks interlace and color range for the
+output frames. It does not change the input frame, but only sets the
+corresponding property, which affects how the frame is treated by
+filters/encoders.
+
+
+- field_mode
+Available values are:
+
+
+- ‘auto’
+Keep the same field property (default).
+
+- ‘bff’
+Mark the frame as bottom-field-first.
+
+- ‘tff’
+Mark the frame as top-field-first.
+
+- ‘prog’
+Mark the frame as progressive.
+
+
+- range
+Available values are:
+
+
+- ‘auto’
+Keep the same color range property (default).
+
+- ‘unspecified, unknown’
+Mark the frame as unspecified color range.
+
+- ‘limited, tv, mpeg’
+Mark the frame as limited range.
+
+- ‘full, pc, jpeg’
+Mark the frame as full range.
+
+
+- color_primaries
+Set the color primaries.
+Available values are:
+
+
+- ‘auto’
+Keep the same color primaries property (default).
+
+- ‘bt709’
+- ‘unknown’
+- ‘bt470m’
+- ‘bt470bg’
+- ‘smpte170m’
+- ‘smpte240m’
+- ‘film’
+- ‘bt2020’
+- ‘smpte428’
+- ‘smpte431’
+- ‘smpte432’
+- ‘jedec-p22’
+
+
+- color_trc
+Set the color transfer.
+Available values are:
+
+
+- ‘auto’
+Keep the same color trc property (default).
+
+- ‘bt709’
+- ‘unknown’
+- ‘bt470m’
+- ‘bt470bg’
+- ‘smpte170m’
+- ‘smpte240m’
+- ‘linear’
+- ‘log100’
+- ‘log316’
+- ‘iec61966-2-4’
+- ‘bt1361e’
+- ‘iec61966-2-1’
+- ‘bt2020-10’
+- ‘bt2020-12’
+- ‘smpte2084’
+- ‘smpte428’
+- ‘arib-std-b67’
+
+
+- colorspace
+Set the colorspace.
+Available values are:
+
+
+- ‘auto’
+Keep the same colorspace property (default).
+
+- ‘gbr’
+- ‘bt709’
+- ‘unknown’
+- ‘fcc’
+- ‘bt470bg’
+- ‘smpte170m’
+- ‘smpte240m’
+- ‘ycgco’
+- ‘bt2020nc’
+- ‘bt2020c’
+- ‘smpte2085’
+- ‘chroma-derived-nc’
+- ‘chroma-derived-c’
+- ‘ictcp’
+
+
+
+
+
+
39.226 sharpen_npp
+
Use the NVIDIA Performance Primitives (libnpp) to perform image sharpening with
+border control.
+
+
The following additional options are accepted:
+
+- border_type
+Type of sampling to be used ad frame borders. One of the following:
+
+- replicate
+Replicate pixel values.
+
+
+
+
+
+
+
39.227 shear
+
Apply shear transform to input video.
+
+
This filter supports the following options:
+
+
+- shx
+Shear factor in X-direction. Default value is 0.
+Allowed range is from -2 to 2.
+
+- shy
+Shear factor in Y-direction. Default value is 0.
+Allowed range is from -2 to 2.
+
+- fillcolor, c
+Set the color used to fill the output area not covered by the transformed
+video. For the general syntax of this option, check the
+(ffmpeg-utils)"Color" section in the ffmpeg-utils manual.
+If the special value "none" is selected then no
+background is printed (useful for example if the background is never shown).
+
+Default value is "black".
+
+- interp
+Set interpolation type. Can be bilinear or nearest. Default is bilinear.
+
+
+
+
+
39.227.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.228 showinfo
+
+
Show a line containing various information for each input video frame.
+The input video is not modified.
+
+
This filter supports the following options:
+
+
+- checksum
+Calculate checksums of each plane. By default enabled.
+
+
+
The shown line contains a sequence of key/value pairs of the form
+key:value.
+
+
The following values are shown in the output:
+
+
+- n
+The (sequential) number of the input frame, starting from 0.
+
+- pts
+The Presentation TimeStamp of the input frame, expressed as a number of
+time base units. The time base unit depends on the filter input pad.
+
+- pts_time
+The Presentation TimeStamp of the input frame, expressed as a number of
+seconds.
+
+- fmt
+The pixel format name.
+
+- sar
+The sample aspect ratio of the input frame, expressed in the form
+num/den.
+
+- s
+The size of the input frame. For the syntax of this option, check the
+(ffmpeg-utils)"Video size" section in the ffmpeg-utils manual.
+
+- i
+The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
+for bottom field first).
+
+- iskey
+This is 1 if the frame is a key frame, 0 otherwise.
+
+- type
+The picture type of the input frame ("I" for an I-frame, "P" for a
+P-frame, "B" for a B-frame, or "?" for an unknown type).
+Also refer to the documentation of the AVPictureType enum and of
+the av_get_picture_type_char function defined in
+libavutil/avutil.h.
+
+- checksum
+The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
+
+- plane_checksum
+The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
+expressed in the form "[c0 c1 c2 c3]".
+
+- mean
+The mean value of pixels in each plane of the input frame, expressed in the form
+"[mean0 mean1 mean2 mean3]".
+
+- stdev
+The standard deviation of pixel values in each plane of the input frame, expressed
+in the form "[stdev0 stdev1 stdev2 stdev3]".
+
+
+
+
+
+
39.229 showpalette
+
+
Displays the 256 colors palette of each frame. This filter is only relevant for
+pal8 pixel format frames.
+
+
It accepts the following option:
+
+
+- s
+Set the size of the box used to represent one palette color entry. Default is
+30 (for a 30x30 pixel box).
+
+
+
+
+
39.230 shuffleframes
+
+
Reorder and/or duplicate and/or drop video frames.
+
+
It accepts the following parameters:
+
+
+- mapping
+Set the destination indexes of input frames.
+This is space or ’|’ separated list of indexes that maps input frames to output
+frames. Number of indexes also sets maximal value that each index may have.
+’-1’ index have special meaning and that is to drop frame.
+
+
+
The first frame has the index 0. The default is to keep the input unchanged.
+
+
+
+
39.230.1 Examples
+
+
+- Swap second and third frame of every three frames of the input:
+
+
ffmpeg -i INPUT -vf "shuffleframes=0 2 1" OUTPUT
+
- Swap 10th and 1st frame of every ten frames of the input:
+
+
ffmpeg -i INPUT -vf "shuffleframes=9 1 2 3 4 5 6 7 8 0" OUTPUT
+
+
+
+
+
+
39.231 shufflepixels
+
+
Reorder pixels in video frames.
+
+
This filter accepts the following options:
+
+
+- direction, d
+Set shuffle direction. Can be forward or inverse direction.
+Default direction is forward.
+
+- mode, m
+Set shuffle mode. Can be horizontal, vertical or block mode.
+
+- width, w
+- height, h
+Set shuffle block_size. In case of horizontal shuffle mode only width
+part of size is used, and in case of vertical shuffle mode only height
+part of size is used.
+
+- seed, s
+Set random seed used with shuffling pixels. Mainly useful to set to be able
+to reverse filtering process to get original input.
+For example, to reverse forward shuffle you need to use same parameters
+and exact same seed and to set direction to inverse.
+
+
+
+
+
39.232 shuffleplanes
+
+
Reorder and/or duplicate video planes.
+
+
It accepts the following parameters:
+
+
+- map0
+The index of the input plane to be used as the first output plane.
+
+- map1
+The index of the input plane to be used as the second output plane.
+
+- map2
+The index of the input plane to be used as the third output plane.
+
+- map3
+The index of the input plane to be used as the fourth output plane.
+
+
+
+
The first plane has the index 0. The default is to keep the input unchanged.
+
+
+
+
39.232.1 Examples
+
+
+- Swap the second and third planes of the input:
+
+
ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
+
+
+
+
+
+
39.233 signalstats
+
Evaluate various visual metrics that assist in determining issues associated
+with the digitization of analog video media.
+
+
By default the filter will log these metadata values:
+
+
+- YMIN
+Display the minimal Y value contained within the input frame. Expressed in
+range of [0-255].
+
+- YLOW
+Display the Y value at the 10% percentile within the input frame. Expressed in
+range of [0-255].
+
+- YAVG
+Display the average Y value within the input frame. Expressed in range of
+[0-255].
+
+- YHIGH
+Display the Y value at the 90% percentile within the input frame. Expressed in
+range of [0-255].
+
+- YMAX
+Display the maximum Y value contained within the input frame. Expressed in
+range of [0-255].
+
+- UMIN
+Display the minimal U value contained within the input frame. Expressed in
+range of [0-255].
+
+- ULOW
+Display the U value at the 10% percentile within the input frame. Expressed in
+range of [0-255].
+
+- UAVG
+Display the average U value within the input frame. Expressed in range of
+[0-255].
+
+- UHIGH
+Display the U value at the 90% percentile within the input frame. Expressed in
+range of [0-255].
+
+- UMAX
+Display the maximum U value contained within the input frame. Expressed in
+range of [0-255].
+
+- VMIN
+Display the minimal V value contained within the input frame. Expressed in
+range of [0-255].
+
+- VLOW
+Display the V value at the 10% percentile within the input frame. Expressed in
+range of [0-255].
+
+- VAVG
+Display the average V value within the input frame. Expressed in range of
+[0-255].
+
+- VHIGH
+Display the V value at the 90% percentile within the input frame. Expressed in
+range of [0-255].
+
+- VMAX
+Display the maximum V value contained within the input frame. Expressed in
+range of [0-255].
+
+- SATMIN
+Display the minimal saturation value contained within the input frame.
+Expressed in range of [0-~181.02].
+
+- SATLOW
+Display the saturation value at the 10% percentile within the input frame.
+Expressed in range of [0-~181.02].
+
+- SATAVG
+Display the average saturation value within the input frame. Expressed in range
+of [0-~181.02].
+
+- SATHIGH
+Display the saturation value at the 90% percentile within the input frame.
+Expressed in range of [0-~181.02].
+
+- SATMAX
+Display the maximum saturation value contained within the input frame.
+Expressed in range of [0-~181.02].
+
+- HUEMED
+Display the median value for hue within the input frame. Expressed in range of
+[0-360].
+
+- HUEAVG
+Display the average value for hue within the input frame. Expressed in range of
+[0-360].
+
+- YDIF
+Display the average of sample value difference between all values of the Y
+plane in the current frame and corresponding values of the previous input frame.
+Expressed in range of [0-255].
+
+- UDIF
+Display the average of sample value difference between all values of the U
+plane in the current frame and corresponding values of the previous input frame.
+Expressed in range of [0-255].
+
+- VDIF
+Display the average of sample value difference between all values of the V
+plane in the current frame and corresponding values of the previous input frame.
+Expressed in range of [0-255].
+
+- YBITDEPTH
+Display bit depth of Y plane in current frame.
+Expressed in range of [0-16].
+
+- UBITDEPTH
+Display bit depth of U plane in current frame.
+Expressed in range of [0-16].
+
+- VBITDEPTH
+Display bit depth of V plane in current frame.
+Expressed in range of [0-16].
+
+
+
The filter accepts the following options:
+
+
+- stat
+- out
+-
+
stat specify an additional form of image analysis.
+out output video with the specified type of pixel highlighted.
+
+Both options accept the following values:
+
+
+- ‘tout’
+Identify temporal outliers pixels. A temporal outlier is a pixel
+unlike the neighboring pixels of the same field. Examples of temporal outliers
+include the results of video dropouts, head clogs, or tape tracking issues.
+
+- ‘vrep’
+Identify vertical line repetition. Vertical line repetition includes
+similar rows of pixels within a frame. In born-digital video vertical line
+repetition is common, but this pattern is uncommon in video digitized from an
+analog source. When it occurs in video that results from the digitization of an
+analog source it can indicate concealment from a dropout compensator.
+
+- ‘brng’
+Identify pixels that fall outside of legal broadcast range.
+
+
+
+- color, c
+Set the highlight color for the out option. The default color is
+yellow.
+
+
+
+
+
39.233.1 Examples
+
+
+
+
+
+
+
39.234 signature
+
+
Calculates the MPEG-7 Video Signature. The filter can handle more than one
+input. In this case the matching between the inputs can be calculated additionally.
+The filter always passes through the first input. The signature of each stream can
+be written into a file.
+
+
It accepts the following options:
+
+
+- detectmode
+Enable or disable the matching process.
+
+Available values are:
+
+
+- ‘off’
+Disable the calculation of a matching (default).
+
- ‘full’
+Calculate the matching for the whole video and output whether the whole video
+matches or only parts.
+
- ‘fast’
+Calculate only until a matching is found or the video ends. Should be faster in
+some cases.
+
+
+- nb_inputs
+Set the number of inputs. The option value must be a non negative integer.
+Default value is 1.
+
+- filename
+Set the path to which the output is written. If there is more than one input,
+the path must be a prototype, i.e. must contain %d or %0nd (where n is a positive
+integer), that will be replaced with the input number. If no filename is
+specified, no output will be written. This is the default.
+
+- format
+Choose the output format.
+
+Available values are:
+
+
+- ‘binary’
+Use the specified binary representation (default).
+
- ‘xml’
+Use the specified xml representation.
+
+
+- th_d
+Set threshold to detect one word as similar. The option value must be an integer
+greater than zero. The default value is 9000.
+
+- th_dc
+Set threshold to detect all words as similar. The option value must be an integer
+greater than zero. The default value is 60000.
+
+- th_xh
+Set threshold to detect frames as similar. The option value must be an integer
+greater than zero. The default value is 116.
+
+- th_di
+Set the minimum length of a sequence in frames to recognize it as matching
+sequence. The option value must be a non negative integer value.
+The default value is 0.
+
+- th_it
+Set the minimum relation, that matching frames to all frames must have.
+The option value must be a double value between 0 and 1. The default value is 0.5.
+
+
+
+
+
39.234.1 Examples
+
+
+- To calculate the signature of an input video and store it in signature.bin:
+
+
ffmpeg -i input.mkv -vf signature=filename=signature.bin -map 0:v -f null -
+
- To detect whether two videos match and store the signatures in XML format in
+signature0.xml and signature1.xml:
+
+
ffmpeg -i input1.mkv -i input2.mkv -filter_complex "[0:v][1:v] signature=nb_inputs=2:detectmode=full:format=xml:filename=signature%d.xml" -map :v -f null -
+
+
+
+
+
+
39.235 siti
+
+
Calculate Spatial Information (SI) and Temporal Information (TI) scores for a video,
+as defined in ITU-T Rec. P.910 (11/21): Subjective video quality assessment methods
+for multimedia applications. Available PDF at https://www.itu.int/rec/T-REC-P.910-202111-S/en.
+Note that this is a legacy implementation that corresponds to a superseded recommendation.
+Refer to ITU-T Rec. P.910 (07/22) for the latest version: https://www.itu.int/rec/T-REC-P.910-202207-I/en
+
+
It accepts the following option:
+
+
+- print_summary
+If set to 1, Summary statistics will be printed to the console. Default 0.
+
+
+
+
+
39.235.1 Examples
+
+- To calculate SI/TI metrics and print summary:
+
+
ffmpeg -i input.mp4 -vf siti=print_summary=1 -f null -
+
+
+
+
+
+
39.236 smartblur
+
+
Blur the input video without impacting the outlines.
+
+
It accepts the following options:
+
+
+- luma_radius, lr
+Set the luma radius. The option value must be a float number in
+the range [0.1,5.0] that specifies the variance of the gaussian filter
+used to blur the image (slower if larger). Default value is 1.0.
+
+- luma_strength, ls
+Set the luma strength. The option value must be a float number
+in the range [-1.0,1.0] that configures the blurring. A value included
+in [0.0,1.0] will blur the image whereas a value included in
+[-1.0,0.0] will sharpen the image. Default value is 1.0.
+
+- luma_threshold, lt
+Set the luma threshold used as a coefficient to determine
+whether a pixel should be blurred or not. The option value must be an
+integer in the range [-30,30]. A value of 0 will filter all the image,
+a value included in [0,30] will filter flat areas and a value included
+in [-30,0] will filter edges. Default value is 0.
+
+- chroma_radius, cr
+Set the chroma radius. The option value must be a float number in
+the range [0.1,5.0] that specifies the variance of the gaussian filter
+used to blur the image (slower if larger). Default value is luma_radius.
+
+- chroma_strength, cs
+Set the chroma strength. The option value must be a float number
+in the range [-1.0,1.0] that configures the blurring. A value included
+in [0.0,1.0] will blur the image whereas a value included in
+[-1.0,0.0] will sharpen the image. Default value is luma_strength.
+
+- chroma_threshold, ct
+Set the chroma threshold used as a coefficient to determine
+whether a pixel should be blurred or not. The option value must be an
+integer in the range [-30,30]. A value of 0 will filter all the image,
+a value included in [0,30] will filter flat areas and a value included
+in [-30,0] will filter edges. Default value is luma_threshold.
+
+
+
If a chroma option is not explicitly set, the corresponding luma value
+is set.
+
+
+
+
39.237 sobel
+
Apply sobel operator to input video stream.
+
+
The filter accepts the following option:
+
+
+- planes
+Set which planes will be processed, unprocessed planes will be copied.
+By default value 0xf, all planes will be processed.
+
+- scale
+Set value which will be multiplied with filtered result.
+
+- delta
+Set value which will be added to filtered result.
+
+
+
+
+
39.237.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.238 spp
+
+
Apply a simple postprocessing filter that compresses and decompresses the image
+at several (or - in the case of quality level 6 - all) shifts
+and average the results.
+
+
The filter accepts the following options:
+
+
+- quality
+Set quality. This option defines the number of levels for averaging. It accepts
+an integer in the range 0-6. If set to 0, the filter will have no
+effect. A value of 6 means the higher quality. For each increment of
+that value the speed drops by a factor of approximately 2. Default value is
+3.
+
+- qp
+Force a constant quantization parameter. If not set, the filter will use the QP
+from the video stream (if available).
+
+- mode
+Set thresholding mode. Available modes are:
+
+
+- ‘hard’
+Set hard thresholding (default).
+
- ‘soft’
+Set soft thresholding (better de-ringing effect, but likely blurrier).
+
+
+- use_bframe_qp
+Enable the use of the QP from the B-Frames if set to 1. Using this
+option may cause flicker since the B-Frames have often larger QP. Default is
+0 (not enabled).
+
+
+
+
+
39.238.1 Commands
+
+
This filter supports the following commands:
+
+- quality, level
+Set quality level. The value max can be used to set the maximum level,
+currently 6.
+
+
+
+
+
+
39.239 sr
+
+
Scale the input by applying one of the super-resolution methods based on
+convolutional neural networks. Supported models:
+
+
+
+
Training scripts as well as scripts for model file (.pb) saving can be found at
+https://github.com/XueweiMeng/sr/tree/sr_dnn_native. Original repository
+is at https://github.com/HighVoltageRocknRoll/sr.git.
+
+
The filter accepts the following options:
+
+
+- dnn_backend
+Specify which DNN backend to use for model loading and execution. This option accepts
+the following values:
+
+
+- ‘tensorflow’
+TensorFlow backend. To enable this backend you
+need to install the TensorFlow for C library (see
+https://www.tensorflow.org/install/lang_c) and configure FFmpeg with
+--enable-libtensorflow
+
+
+- model
+Set path to model file specifying network architecture and its parameters.
+Note that different backends use different file formats. TensorFlow, OpenVINO backend
+can load files for only its format.
+
+- scale_factor
+Set scale factor for SRCNN model. Allowed values are 2, 3 and 4.
+Default value is 2. Scale factor is necessary for SRCNN model, because it accepts
+input upscaled using bicubic upscaling with proper scale factor.
+
+
+
To get full functionality (such as async execution), please use the dnn_processing filter.
+
+
+
+
39.240 ssim
+
+
Obtain the SSIM (Structural SImilarity Metric) between two input videos.
+
+
This filter takes in input two input videos, the first input is
+considered the "main" source and is passed unchanged to the
+output. The second input is used as a "reference" video for computing
+the SSIM.
+
+
Both video inputs must have the same resolution and pixel format for
+this filter to work correctly. Also it assumes that both inputs
+have the same number of frames, which are compared one by one.
+
+
The filter stores the calculated SSIM of each frame.
+
+
The description of the accepted parameters follows.
+
+
+- stats_file, f
+If specified the filter will use the named file to save the SSIM of
+each individual frame. When filename equals "-" the data is sent to
+standard output.
+
+
+
The file printed if stats_file is selected, contains a sequence of
+key/value pairs of the form key:value for each compared
+couple of frames.
+
+
A description of each shown parameter follows:
+
+
+- n
+sequential number of the input frame, starting from 1
+
+- Y, U, V, R, G, B
+SSIM of the compared frames for the component specified by the suffix.
+
+- All
+SSIM of the compared frames for the whole frame.
+
+- dB
+Same as above but in dB representation.
+
+
+
This filter also supports the framesync options.
+
+
+
+
+
+
39.241 stereo3d
+
+
Convert between different stereoscopic image formats.
+
+
The filters accept the following options:
+
+
+- in
+Set stereoscopic image format of input.
+
+Available values for input image formats are:
+
+- ‘sbsl’
+side by side parallel (left eye left, right eye right)
+
+- ‘sbsr’
+side by side crosseye (right eye left, left eye right)
+
+- ‘sbs2l’
+side by side parallel with half width resolution
+(left eye left, right eye right)
+
+- ‘sbs2r’
+side by side crosseye with half width resolution
+(right eye left, left eye right)
+
+- ‘abl’
+- ‘tbl’
+above-below (left eye above, right eye below)
+
+- ‘abr’
+- ‘tbr’
+above-below (right eye above, left eye below)
+
+- ‘ab2l’
+- ‘tb2l’
+above-below with half height resolution
+(left eye above, right eye below)
+
+- ‘ab2r’
+- ‘tb2r’
+above-below with half height resolution
+(right eye above, left eye below)
+
+- ‘al’
+alternating frames (left eye first, right eye second)
+
+- ‘ar’
+alternating frames (right eye first, left eye second)
+
+- ‘irl’
+interleaved rows (left eye has top row, right eye starts on next row)
+
+- ‘irr’
+interleaved rows (right eye has top row, left eye starts on next row)
+
+- ‘icl’
+interleaved columns, left eye first
+
+- ‘icr’
+interleaved columns, right eye first
+
+Default value is ‘sbsl’.
+
+
+- out
+Set stereoscopic image format of output.
+
+
+- ‘sbsl’
+side by side parallel (left eye left, right eye right)
+
+- ‘sbsr’
+side by side crosseye (right eye left, left eye right)
+
+- ‘sbs2l’
+side by side parallel with half width resolution
+(left eye left, right eye right)
+
+- ‘sbs2r’
+side by side crosseye with half width resolution
+(right eye left, left eye right)
+
+- ‘abl’
+- ‘tbl’
+above-below (left eye above, right eye below)
+
+- ‘abr’
+- ‘tbr’
+above-below (right eye above, left eye below)
+
+- ‘ab2l’
+- ‘tb2l’
+above-below with half height resolution
+(left eye above, right eye below)
+
+- ‘ab2r’
+- ‘tb2r’
+above-below with half height resolution
+(right eye above, left eye below)
+
+- ‘al’
+alternating frames (left eye first, right eye second)
+
+- ‘ar’
+alternating frames (right eye first, left eye second)
+
+- ‘irl’
+interleaved rows (left eye has top row, right eye starts on next row)
+
+- ‘irr’
+interleaved rows (right eye has top row, left eye starts on next row)
+
+- ‘arbg’
+anaglyph red/blue gray
+(red filter on left eye, blue filter on right eye)
+
+- ‘argg’
+anaglyph red/green gray
+(red filter on left eye, green filter on right eye)
+
+- ‘arcg’
+anaglyph red/cyan gray
+(red filter on left eye, cyan filter on right eye)
+
+- ‘arch’
+anaglyph red/cyan half colored
+(red filter on left eye, cyan filter on right eye)
+
+- ‘arcc’
+anaglyph red/cyan color
+(red filter on left eye, cyan filter on right eye)
+
+- ‘arcd’
+anaglyph red/cyan color optimized with the least squares projection of dubois
+(red filter on left eye, cyan filter on right eye)
+
+- ‘agmg’
+anaglyph green/magenta gray
+(green filter on left eye, magenta filter on right eye)
+
+- ‘agmh’
+anaglyph green/magenta half colored
+(green filter on left eye, magenta filter on right eye)
+
+- ‘agmc’
+anaglyph green/magenta colored
+(green filter on left eye, magenta filter on right eye)
+
+- ‘agmd’
+anaglyph green/magenta color optimized with the least squares projection of dubois
+(green filter on left eye, magenta filter on right eye)
+
+- ‘aybg’
+anaglyph yellow/blue gray
+(yellow filter on left eye, blue filter on right eye)
+
+- ‘aybh’
+anaglyph yellow/blue half colored
+(yellow filter on left eye, blue filter on right eye)
+
+- ‘aybc’
+anaglyph yellow/blue colored
+(yellow filter on left eye, blue filter on right eye)
+
+- ‘aybd’
+anaglyph yellow/blue color optimized with the least squares projection of dubois
+(yellow filter on left eye, blue filter on right eye)
+
+- ‘ml’
+mono output (left eye only)
+
+- ‘mr’
+mono output (right eye only)
+
+- ‘chl’
+checkerboard, left eye first
+
+- ‘chr’
+checkerboard, right eye first
+
+- ‘icl’
+interleaved columns, left eye first
+
+- ‘icr’
+interleaved columns, right eye first
+
+- ‘hdmi’
+HDMI frame pack
+
+
+Default value is ‘arcd’.
+
+
+
+
+
39.241.1 Examples
+
+
+- Convert input video from side by side parallel to anaglyph yellow/blue dubois:
+
+
+
- Convert input video from above below (left eye above, right eye below) to side by side crosseye.
+
+
+
+
+
+
+
39.242 streamselect, astreamselect
+
Select video or audio streams.
+
+
The filter accepts the following options:
+
+
+- inputs
+Set number of inputs. Default is 2.
+
+- map
+Set input indexes to remap to outputs.
+
+
+
+
+
39.242.1 Commands
+
+
The streamselect and astreamselect filter supports the following
+commands:
+
+
+- map
+Set input indexes to remap to outputs.
+
+
+
+
+
39.242.2 Examples
+
+
+- Select first 5 seconds 1st stream and rest of time 2nd stream:
+
+
sendcmd='5.0 streamselect map 1',streamselect=inputs=2:map=0
+
- Same as above, but for audio:
+
+
asendcmd='5.0 astreamselect map 1',astreamselect=inputs=2:map=0
+
+
+
+
+
+
39.243 subtitles
+
+
Draw subtitles on top of input video using the libass library.
+
+
To enable compilation of this filter you need to configure FFmpeg with
+--enable-libass. This filter also requires a build with libavcodec and
+libavformat to convert the passed subtitles file to ASS (Advanced Substation
+Alpha) subtitles format.
+
+
The filter accepts the following options:
+
+
+- filename, f
+Set the filename of the subtitle file to read. It must be specified.
+
+- original_size
+Specify the size of the original video, the video for which the ASS file
+was composed. For the syntax of this option, check the
+(ffmpeg-utils)"Video size" section in the ffmpeg-utils manual.
+Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
+correctly scale the fonts if the aspect ratio has been changed.
+
+- fontsdir
+Set a directory path containing fonts that can be used by the filter.
+These fonts will be used in addition to whatever the font provider uses.
+
+- alpha
+Process alpha channel, by default alpha channel is untouched.
+
+- charenc
+Set subtitles input character encoding. subtitles filter only. Only
+useful if not UTF-8.
+
+- stream_index, si
+Set subtitles stream index. subtitles filter only.
+
+- force_style
+Override default style or script info parameters of the subtitles. It accepts a
+string containing ASS style format KEY=VALUE couples separated by ",".
+
+
+
If the first key is not specified, it is assumed that the first value
+specifies the filename.
+
+
For example, to render the file sub.srt on top of the input
+video, use the command:
+
+
+
which is equivalent to:
+
+
subtitles=filename=sub.srt
+
+
+
To render the default subtitles stream from file video.mkv, use:
+
+
+
To render the second subtitles stream from that file, use:
+
+
subtitles=video.mkv:si=1
+
+
+
To make the subtitles stream from sub.srt appear in 80% transparent blue
+DejaVu Serif, use:
+
+
subtitles=sub.srt:force_style='Fontname=DejaVu Serif,PrimaryColour=&HCCFF0000'
+
+
+
+
+
39.244 super2xsai
+
+
Scale the input by 2x and smooth using the Super2xSaI (Scale and
+Interpolate) pixel art scaling algorithm.
+
+
Useful for enlarging pixel art images without reducing sharpness.
+
+
+
+
39.245 swaprect
+
+
Swap two rectangular objects in video.
+
+
This filter accepts the following options:
+
+
+- w
+Set object width.
+
+- h
+Set object height.
+
+- x1
+Set 1st rect x coordinate.
+
+- y1
+Set 1st rect y coordinate.
+
+- x2
+Set 2nd rect x coordinate.
+
+- y2
+Set 2nd rect y coordinate.
+
+All expressions are evaluated once for each frame.
+
+
+
The all options are expressions containing the following constants:
+
+
+- w
+- h
+The input width and height.
+
+- a
+same as w / h
+
+- sar
+input sample aspect ratio
+
+- dar
+input display aspect ratio, it is the same as (w / h) * sar
+
+- n
+The number of the input frame, starting from 0.
+
+- t
+The timestamp expressed in seconds. It’s NAN if the input timestamp is unknown.
+
+- pos
+the position in the file of the input frame, NAN if unknown; deprecated,
+do not use
+
+
+
+
+
39.245.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.246 swapuv
+
Swap U & V plane.
+
+
+
+
39.247 tblend
+
Blend successive video frames.
+
+
See blend
+
+
+
+
39.248 telecine
+
+
Apply telecine process to the video.
+
+
This filter accepts the following options:
+
+
+- first_field
+
+- ‘top, t’
+top field first
+
- ‘bottom, b’
+bottom field first
+The default value is top.
+
+
+- pattern
+A string of numbers representing the pulldown pattern you wish to apply.
+The default value is 23.
+
+
+
+
Some typical patterns:
+
+NTSC output (30i):
+27.5p: 32222
+24p: 23 (classic)
+24p: 2332 (preferred)
+20p: 33
+18p: 334
+16p: 3444
+
+PAL output (25i):
+27.5p: 12222
+24p: 222222222223 ("Euro pulldown")
+16.67p: 33
+16p: 33333334
+
+
+
+
+
39.249 thistogram
+
+
Compute and draw a color distribution histogram for the input video across time.
+
+
Unlike histogram video filter which only shows histogram of single input frame
+at certain time, this filter shows also past histograms of number of frames defined
+by width option.
+
+
The computed histogram is a representation of the color component
+distribution in an image.
+
+
The filter accepts the following options:
+
+
+- width, w
+Set width of single color component output. Default value is 0.
+Value of 0 means width will be picked from input video.
+This also set number of passed histograms to keep.
+Allowed range is [0, 8192].
+
+- display_mode, d
+Set display mode.
+It accepts the following values:
+
+- ‘stack’
+Per color component graphs are placed below each other.
+
+- ‘parade’
+Per color component graphs are placed side by side.
+
+- ‘overlay’
+Presents information identical to that in the parade, except
+that the graphs representing color components are superimposed directly
+over one another.
+
+Default is stack.
+
+- levels_mode, m
+Set mode. Can be either linear, or logarithmic.
+Default is linear.
+
+- components, c
+Set what color components to display.
+Default is 7.
+
+- bgopacity, b
+Set background opacity. Default is 0.9.
+
+- envelope, e
+Show envelope. Default is disabled.
+
+- ecolor, ec
+Set envelope color. Default is gold.
+
+- slide
+Set slide mode.
+
+Available values for slide is:
+
+- ‘frame’
+Draw new frame when right border is reached.
+
+- ‘replace’
+Replace old columns with new ones.
+
+- ‘scroll’
+Scroll from right to left.
+
+- ‘rscroll’
+Scroll from left to right.
+
+- ‘picture’
+Draw single picture.
+
+
+Default is replace.
+
+
+
+
+
39.250 threshold
+
+
Apply threshold effect to video stream.
+
+
This filter needs four video streams to perform thresholding.
+First stream is stream we are filtering.
+Second stream is holding threshold values, third stream is holding min values,
+and last, fourth stream is holding max values.
+
+
The filter accepts the following option:
+
+
+- planes
+Set which planes will be processed, unprocessed planes will be copied.
+By default value 0xf, all planes will be processed.
+
+
+
For example if first stream pixel’s component value is less then threshold value
+of pixel component from 2nd threshold stream, third stream value will picked,
+otherwise fourth stream pixel component value will be picked.
+
+
Using color source filter one can perform various types of thresholding:
+
+
+
+
39.250.1 Commands
+
+
This filter supports the all options as commands.
+
+
+
+
39.250.2 Examples
+
+
+- Binary threshold, using gray color as threshold:
+
+
ffmpeg -i 320x240.avi -f lavfi -i color=gray -f lavfi -i color=black -f lavfi -i color=white -lavfi threshold output.avi
+
- Inverted binary threshold, using gray color as threshold:
+
+
ffmpeg -i 320x240.avi -f lavfi -i color=gray -f lavfi -i color=white -f lavfi -i color=black -lavfi threshold output.avi
+
- Truncate binary threshold, using gray color as threshold:
+
+
ffmpeg -i 320x240.avi -f lavfi -i color=gray -i 320x240.avi -f lavfi -i color=gray -lavfi threshold output.avi
+
- Threshold to zero, using gray color as threshold:
+
+
ffmpeg -i 320x240.avi -f lavfi -i color=gray -f lavfi -i color=white -i 320x240.avi -lavfi threshold output.avi
+
- Inverted threshold to zero, using gray color as threshold:
+
+
ffmpeg -i 320x240.avi -f lavfi -i color=gray -i 320x240.avi -f lavfi -i color=white -lavfi threshold output.avi
+
+
+
+
+
+
39.251 thumbnail
+
Select the most representative frame in a given sequence of consecutive frames.
+
+
The filter accepts the following options:
+
+
+- n
+Set the frames batch size to analyze; in a set of n frames, the filter
+will pick one of them, and then handle the next batch of n frames until
+the end. Default is 100.
+
+- log
+Set the log level to display picked frame stats.
+Default is info.
+
+
+
Since the filter keeps track of the whole frames sequence, a bigger n
+value will result in a higher memory usage, so a high value is not recommended.
+
+
+
+
39.251.1 Examples
+
+
+- Extract one picture each 50 frames:
+
+
+
- Complete example of a thumbnail creation with
ffmpeg:
+
+
ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
+
+
+
+
+
+
39.252 tile
+
+
Tile several successive frames together.
+
+
The untile filter can do the reverse.
+
+
The filter accepts the following options:
+
+
+- layout
+Set the grid size in the form COLUMNSxROWS. Range is upto UINT_MAX cells.
+Default is 6x5.
+
+- nb_frames
+Set the maximum number of frames to render in the given area. It must be less
+than or equal to wxh. The default value is 0, meaning all
+the area will be used.
+
+- margin
+Set the outer border margin in pixels. Range is 0 to 1024. Default is 0.
+
+- padding
+Set the inner border thickness (i.e. the number of pixels between frames). For
+more advanced padding options (such as having different values for the edges),
+refer to the pad video filter. Range is 0 to 1024. Default is 0.
+
+- color
+Specify the color of the unused area. For the syntax of this option, check the
+(ffmpeg-utils)"Color" section in the ffmpeg-utils manual.
+The default value of color is "black".
+
+- overlap
+Set the number of frames to overlap when tiling several successive frames together.
+The value must be between 0 and nb_frames - 1. Default is 0.
+
+- init_padding
+Set the number of frames to initially be empty before displaying first output frame.
+This controls how soon will one get first output frame.
+The value must be between 0 and nb_frames - 1. Default is 0.
+
+
+
+
+
39.252.1 Examples
+
+
+
+
+
+
+
39.253 tinterlace
+
+
Perform various types of temporal field interlacing.
+
+
Frames are counted starting from 1, so the first input frame is
+considered odd.
+
+
The filter accepts the following options:
+
+
+- mode
+Specify the mode of the interlacing. This option can also be specified
+as a value alone. See below for a list of values for this option.
+
+Available values are:
+
+
+- ‘merge, 0’
+Move odd frames into the upper field, even into the lower field,
+generating a double height frame at half frame rate.
+
+
------> time
+Input:
+Frame 1 Frame 2 Frame 3 Frame 4
+
+11111 22222 33333 44444
+11111 22222 33333 44444
+11111 22222 33333 44444
+11111 22222 33333 44444
+
+Output:
+11111 33333
+22222 44444
+11111 33333
+22222 44444
+11111 33333
+22222 44444
+11111 33333
+22222 44444
+
- ‘drop_even, 1’
+Only output odd frames, even frames are dropped, generating a frame with
+unchanged height at half frame rate.
+
+
+
------> time
+Input:
+Frame 1 Frame 2 Frame 3 Frame 4
+
+11111 22222 33333 44444
+11111 22222 33333 44444
+11111 22222 33333 44444
+11111 22222 33333 44444
+
+Output:
+11111 33333
+11111 33333
+11111 33333
+11111 33333
+
- ‘drop_odd, 2’
+Only output even frames, odd frames are dropped, generating a frame with
+unchanged height at half frame rate.
+
+
+
------> time
+Input:
+Frame 1 Frame 2 Frame 3 Frame 4
+
+11111 22222 33333 44444
+11111 22222 33333 44444
+11111 22222 33333 44444
+11111 22222 33333 44444
+
+Output:
+ 22222 44444
+ 22222 44444
+ 22222 44444
+ 22222 44444
+
- ‘pad, 3’
+Expand each frame to full height, but pad alternate lines with black,
+generating a frame with double height at the same input frame rate.
+
+
+
------> time
+Input:
+Frame 1 Frame 2 Frame 3 Frame 4
+
+11111 22222 33333 44444
+11111 22222 33333 44444
+11111 22222 33333 44444
+11111 22222 33333 44444
+
+Output:
+11111 ..... 33333 .....
+..... 22222 ..... 44444
+11111 ..... 33333 .....
+..... 22222 ..... 44444
+11111 ..... 33333 .....
+..... 22222 ..... 44444
+11111 ..... 33333 .....
+..... 22222 ..... 44444
+
- ‘interleave_top, 4’
+Interleave the upper field from odd frames with the lower field from
+even frames, generating a frame with unchanged height at half frame rate.
+
+
+
------> time
+Input:
+Frame 1 Frame 2 Frame 3 Frame 4
+
+11111<- 22222 33333<- 44444
+11111 22222<- 33333 44444<-
+11111<- 22222 33333<- 44444
+11111 22222<- 33333 44444<-
+
+Output:
+11111 33333
+22222 44444
+11111 33333
+22222 44444
+
- ‘interleave_bottom, 5’
+Interleave the lower field from odd frames with the upper field from
+even frames, generating a frame with unchanged height at half frame rate.
+
+
+
------> time
+Input:
+Frame 1 Frame 2 Frame 3 Frame 4
+
+11111 22222<- 33333 44444<-
+11111<- 22222 33333<- 44444
+11111 22222<- 33333 44444<-
+11111<- 22222 33333<- 44444
+
+Output:
+22222 44444
+11111 33333
+22222 44444
+11111 33333
+
- ‘interlacex2, 6’
+Double frame rate with unchanged height. Frames are inserted each
+containing the second temporal field from the previous input frame and
+the first temporal field from the next input frame. This mode relies on
+the top_field_first flag. Useful for interlaced video displays with no
+field synchronisation.
+
+
+
------> time
+Input:
+Frame 1 Frame 2 Frame 3 Frame 4
+
+11111 22222 33333 44444
+ 11111 22222 33333 44444
+11111 22222 33333 44444
+ 11111 22222 33333 44444
+
+Output:
+11111 22222 22222 33333 33333 44444 44444
+ 11111 11111 22222 22222 33333 33333 44444
+11111 22222 22222 33333 33333 44444 44444
+ 11111 11111 22222 22222 33333 33333 44444
+
- ‘mergex2, 7’
+Move odd frames into the upper field, even into the lower field,
+generating a double height frame at same frame rate.
+
+
+
------> time
+Input:
+Frame 1 Frame 2 Frame 3 Frame 4
+
+11111 22222 33333 44444
+11111 22222 33333 44444
+11111 22222 33333 44444
+11111 22222 33333 44444
+
+Output:
+11111 33333 33333 55555
+22222 22222 44444 44444
+11111 33333 33333 55555
+22222 22222 44444 44444
+11111 33333 33333 55555
+22222 22222 44444 44444
+11111 33333 33333 55555
+22222 22222 44444 44444
+
+
+Numeric values are deprecated but are accepted for backward
+compatibility reasons.
+
+Default mode is merge.
+
+- flags
+Specify flags influencing the filter process.
+
+Available value for flags is:
+
+
+- low_pass_filter, vlpf
+Enable linear vertical low-pass filtering in the filter.
+Vertical low-pass filtering is required when creating an interlaced
+destination from a progressive source which contains high-frequency
+vertical detail. Filtering will reduce interlace ’twitter’ and Moire
+patterning.
+
+- complex_filter, cvlpf
+Enable complex vertical low-pass filtering.
+This will slightly less reduce interlace ’twitter’ and Moire
+patterning but better retain detail and subjective sharpness impression.
+
+- bypass_il
+Bypass already interlaced frames, only adjust the frame rate.
+
+
+Vertical low-pass filtering and bypassing already interlaced frames can only be
+enabled for mode interleave_top and interleave_bottom.
+
+
+
+
+
+
+
39.255 tmidequalizer
+
+
Apply Temporal Midway Video Equalization effect.
+
+
Midway Video Equalization adjusts a sequence of video frames to have the same
+histograms, while maintaining their dynamics as much as possible. It’s
+useful for e.g. matching exposures from a video frames sequence.
+
+
This filter accepts the following option:
+
+
+- radius
+Set filtering radius. Default is 5. Allowed range is from 1 to 127.
+
+- sigma
+Set filtering sigma. Default is 0.5. This controls strength of filtering.
+Setting this option to 0 effectively does nothing.
+
+- planes
+Set which planes to process. Default is 15, which is all available planes.
+
+
+
+
+
39.256 tmix
+
+
Mix successive video frames.
+
+
A description of the accepted options follows.
+
+
+- frames
+The number of successive frames to mix. If unspecified, it defaults to 3.
+
+- weights
+Specify weight of each input video frame.
+Each weight is separated by space. If number of weights is smaller than
+number of frames last specified weight will be used for all remaining
+unset weights.
+
+- scale
+Specify scale, if it is set it will be multiplied with sum
+of each weight multiplied with pixel values to give final destination
+pixel value. By default scale is auto scaled to sum of weights.
+
+- planes
+Set which planes to filter. Default is all. Allowed range is from 0 to 15.
+
+
+
+
+
39.256.1 Examples
+
+
+- Average 7 successive frames:
+
+
tmix=frames=7:weights="1 1 1 1 1 1 1"
+
- Apply simple temporal convolution:
+
+
tmix=frames=3:weights="-1 3 -1"
+
- Similar as above but only showing temporal differences:
+
+
tmix=frames=3:weights="-1 2 -1":scale=1
+
+
+
+
+
39.256.2 Commands
+
+
This filter supports the following commands:
+
+- weights
+- scale
+- planes
+Syntax is same as option with same name.
+
+
+
+
+
+
39.257 tonemap
+
Tone map colors from different dynamic ranges.
+
+
This filter expects data in single precision floating point, as it needs to
+operate on (and can output) out-of-range values. Another filter, such as
+zscale, is needed to convert the resulting frame to a usable format.
+
+
The tonemapping algorithms implemented only work on linear light, so input
+data should be linearized beforehand (and possibly correctly tagged).
+
+
+
ffmpeg -i INPUT -vf zscale=transfer=linear,tonemap=clip,zscale=transfer=bt709,format=yuv420p OUTPUT
+
+
+
+
+
39.257.1 Options
+
The filter accepts the following options.
+
+
+- tonemap
+Set the tone map algorithm to use.
+
+Possible values are:
+
+- none
+Do not apply any tone map, only desaturate overbright pixels.
+
+- clip
+Hard-clip any out-of-range values. Use it for perfect color accuracy for
+in-range values, while distorting out-of-range values.
+
+- linear
+Stretch the entire reference gamut to a linear multiple of the display.
+
+- gamma
+Fit a logarithmic transfer between the tone curves.
+
+- reinhard
+Preserve overall image brightness with a simple curve, using nonlinear
+contrast, which results in flattening details and degrading color accuracy.
+
+- hable
+Preserve both dark and bright details better than reinhard, at the cost
+of slightly darkening everything. Use it when detail preservation is more
+important than color and brightness accuracy.
+
+- mobius
+Smoothly map out-of-range values, while retaining contrast and colors for
+in-range material as much as possible. Use it when color accuracy is more
+important than detail preservation.
+
+
+Default is none.
+
+- param
+Tune the tone mapping algorithm.
+
+This affects the following algorithms:
+
+- none
+Ignored.
+
+- linear
+Specifies the scale factor to use while stretching.
+Default to 1.0.
+
+- gamma
+Specifies the exponent of the function.
+Default to 1.8.
+
+- clip
+Specify an extra linear coefficient to multiply into the signal before clipping.
+Default to 1.0.
+
+- reinhard
+Specify the local contrast coefficient at the display peak.
+Default to 0.5, which means that in-gamut values will be about half as bright
+as when clipping.
+
+- hable
+Ignored.
+
+- mobius
+Specify the transition point from linear to mobius transform. Every value
+below this point is guaranteed to be mapped 1:1. The higher the value, the
+more accurate the result will be, at the cost of losing bright details.
+Default to 0.3, which due to the steep initial slope still preserves in-range
+colors fairly accurately.
+
+
+- desat
+Apply desaturation for highlights that exceed this level of brightness. The
+higher the parameter, the more color information will be preserved. This
+setting helps prevent unnaturally blown-out colors for super-highlights, by
+(smoothly) turning into white instead. This makes images feel more natural,
+at the cost of reducing information about out-of-range colors.
+
+The default of 2.0 is somewhat conservative and will mostly just apply to
+skies or directly sunlit surfaces. A setting of 0.0 disables this option.
+
+This option works only if the input frame has a supported color tag.
+
+- peak
+Override signal/nominal/reference peak with this value. Useful when the
+embedded peak information in display metadata is not reliable or when tone
+mapping from a lower range to a higher range.
+
+
+
+
+
+
39.258 tpad
+
+
Temporarily pad video frames.
+
+
The filter accepts the following options:
+
+
+- start
+Specify number of delay frames before input video stream. Default is 0.
+
+- stop
+Specify number of padding frames after input video stream.
+Set to -1 to pad indefinitely. Default is 0.
+
+- start_mode
+Set kind of frames added to beginning of stream.
+Can be either add or clone.
+With add frames of solid-color are added.
+With clone frames are clones of first frame.
+Default is add.
+
+- stop_mode
+Set kind of frames added to end of stream.
+Can be either add or clone.
+With add frames of solid-color are added.
+With clone frames are clones of last frame.
+Default is add.
+
+- start_duration, stop_duration
+Specify the duration of the start/stop delay. See
+(ffmpeg-utils)the Time duration section in the ffmpeg-utils(1) manual
+for the accepted syntax.
+These options override start and stop. Default is 0.
+
+- color
+Specify the color of the padded area. For the syntax of this option,
+check the (ffmpeg-utils)"Color" section in the ffmpeg-utils
+manual.
+
+The default value of color is "black".
+
+
+
+
+
39.259 transpose
+
+
Transpose rows with columns in the input video and optionally flip it.
+
+
It accepts the following parameters:
+
+
+- dir
+Specify the transposition direction.
+
+Can assume the following values:
+
+- ‘0, 4, cclock_flip’
+Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
+
+
L.R L.l
+. . -> . .
+l.r R.r
+
- ‘1, 5, clock’
+Rotate by 90 degrees clockwise, that is:
+
+
L.R l.L
+. . -> . .
+l.r r.R
+
- ‘2, 6, cclock’
+Rotate by 90 degrees counterclockwise, that is:
+
+
L.R R.r
+. . -> . .
+l.r L.l
+
- ‘3, 7, clock_flip’
+Rotate by 90 degrees clockwise and vertically flip, that is:
+
+
L.R r.R
+. . -> . .
+l.r l.L
+
+
+For values between 4-7, the transposition is only done if the input
+video geometry is portrait and not landscape. These values are
+deprecated, the passthrough option should be used instead.
+
+Numerical values are deprecated, and should be dropped in favor of
+symbolic constants.
+
+- passthrough
+Do not apply the transposition if the input geometry matches the one
+specified by the specified value. It accepts the following values:
+
+- ‘none’
+Always apply transposition.
+
- ‘portrait’
+Preserve portrait geometry (when height >= width).
+
- ‘landscape’
+Preserve landscape geometry (when width >= height).
+
+
+Default value is none.
+
+
+
For example to rotate by 90 degrees clockwise and preserve portrait
+layout:
+
+
transpose=dir=1:passthrough=portrait
+
+
+
The command above can also be specified as:
+
+
+
+
+
39.260 transpose_npp
+
+
Transpose rows with columns in the input video and optionally flip it.
+For more in depth examples see the transpose video filter, which shares mostly the same options.
+
+
It accepts the following parameters:
+
+
+- dir
+Specify the transposition direction.
+
+Can assume the following values:
+
+- ‘cclock_flip’
+Rotate by 90 degrees counterclockwise and vertically flip. (default)
+
+- ‘clock’
+Rotate by 90 degrees clockwise.
+
+- ‘cclock’
+Rotate by 90 degrees counterclockwise.
+
+- ‘clock_flip’
+Rotate by 90 degrees clockwise and vertically flip.
+
+
+- passthrough
+Do not apply the transposition if the input geometry matches the one
+specified by the specified value. It accepts the following values:
+
+- ‘none’
+Always apply transposition. (default)
+
- ‘portrait’
+Preserve portrait geometry (when height >= width).
+
- ‘landscape’
+Preserve landscape geometry (when width >= height).
+
+
+
+
+
+
+
39.261 trim
+
Trim the input so that the output contains one continuous subpart of the input.
+
+
It accepts the following parameters:
+
+- start
+Specify the time of the start of the kept section, i.e. the frame with the
+timestamp start will be the first frame in the output.
+
+- end
+Specify the time of the first frame that will be dropped, i.e. the frame
+immediately preceding the one with the timestamp end will be the last
+frame in the output.
+
+- start_pts
+This is the same as start, except this option sets the start timestamp
+in timebase units instead of seconds.
+
+- end_pts
+This is the same as end, except this option sets the end timestamp
+in timebase units instead of seconds.
+
+- duration
+The maximum duration of the output in seconds.
+
+- start_frame
+The number of the first frame that should be passed to the output.
+
+- end_frame
+The number of the first frame that should be dropped.
+
+
+
start, end, and duration are expressed as time
+duration specifications; see
+(ffmpeg-utils)the Time duration section in the ffmpeg-utils(1) manual
+for the accepted syntax.
+
+
Note that the first two sets of the start/end options and the duration
+option look at the frame timestamp, while the _frame variants simply count the
+frames that pass through the filter. Also note that this filter does not modify
+the timestamps. If you wish for the output timestamps to start at zero, insert a
+setpts filter after the trim filter.
+
+
If multiple start or end options are set, this filter tries to be greedy and
+keep all the frames that match at least one of the specified constraints. To keep
+only the part that matches all the constraints at once, chain multiple trim
+filters.
+
+
The defaults are such that all the input is kept. So it is possible to set e.g.
+just the end values to keep everything before the specified time.
+
+
Examples:
+
+- Drop everything except the second minute of input:
+
+
ffmpeg -i INPUT -vf trim=60:120
+
- Keep only the first second:
+
+
ffmpeg -i INPUT -vf trim=duration=1
+
+
+
+
+
39.262 unpremultiply
+
Apply alpha unpremultiply effect to input video stream using first plane
+of second stream as alpha.
+
+
Both streams must have same dimensions and same pixel format.
+
+
The filter accepts the following option:
+
+
+- planes
+Set which planes will be processed, unprocessed planes will be copied.
+By default value 0xf, all planes will be processed.
+
+If the format has 1 or 2 components, then luma is bit 0.
+If the format has 3 or 4 components:
+for RGB formats bit 0 is green, bit 1 is blue and bit 2 is red;
+for YUV formats bit 0 is luma, bit 1 is chroma-U and bit 2 is chroma-V.
+If present, the alpha channel is always the last bit.
+
+- inplace
+Do not require 2nd input for processing, instead use alpha plane from input stream.
+
+
+
+
+
39.263 unsharp
+
+
Sharpen or blur the input video.
+
+
It accepts the following parameters:
+
+
+- luma_msize_x, lx
+Set the luma matrix horizontal size. It must be an odd integer between
+3 and 23. The default value is 5.
+
+- luma_msize_y, ly
+Set the luma matrix vertical size. It must be an odd integer between 3
+and 23. The default value is 5.
+
+- luma_amount, la
+Set the luma effect strength. It must be a floating point number, reasonable
+values lay between -1.5 and 1.5.
+
+Negative values will blur the input video, while positive values will
+sharpen it, a value of zero will disable the effect.
+
+Default value is 1.0.
+
+- chroma_msize_x, cx
+Set the chroma matrix horizontal size. It must be an odd integer
+between 3 and 23. The default value is 5.
+
+- chroma_msize_y, cy
+Set the chroma matrix vertical size. It must be an odd integer
+between 3 and 23. The default value is 5.
+
+- chroma_amount, ca
+Set the chroma effect strength. It must be a floating point number, reasonable
+values lay between -1.5 and 1.5.
+
+Negative values will blur the input video, while positive values will
+sharpen it, a value of zero will disable the effect.
+
+Default value is 0.0.
+
+- alpha_msize_x, ax
+Set the alpha matrix horizontal size. It must be an odd integer
+between 3 and 23. The default value is 5.
+
+- alpha_msize_y, ay
+Set the alpha matrix vertical size. It must be an odd integer
+between 3 and 23. The default value is 5.
+
+- alpha_amount, aa
+Set the alpha effect strength. It must be a floating point number, reasonable
+values lay between -1.5 and 1.5.
+
+Negative values will blur the input video, while positive values will
+sharpen it, a value of zero will disable the effect.
+
+Default value is 0.0.
+
+
+
+
All parameters are optional and default to the equivalent of the
+string ’5:5:1.0:5:5:0.0’.
+
+
+
+
39.263.1 Examples
+
+
+- Apply strong luma sharpen effect:
+
+
unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
+
- Apply a strong blur of both luma and chroma parameters:
+
+
+
+
+
+
+
39.264 untile
+
+
Decompose a video made of tiled images into the individual images.
+
+
The frame rate of the output video is the frame rate of the input video
+multiplied by the number of tiles.
+
+
This filter does the reverse of tile.
+
+
The filter accepts the following options:
+
+
+- layout
+Set the grid size (i.e. the number of lines and columns). For the syntax of
+this option, check the
+(ffmpeg-utils)"Video size" section in the ffmpeg-utils manual.
+
+
+
+
+
39.264.1 Examples
+
+
+- Produce a 1-second video from a still image file made of 25 frames stacked
+vertically, like an analogic film reel:
+
+
ffmpeg -r 1 -i image.jpg -vf untile=1x25 movie.mkv
+
+
+
+
+
+
39.265 uspp
+
+
Apply ultra slow/simple postprocessing filter that compresses and decompresses
+the image at several (or - in the case of quality level 8 - all)
+shifts and average the results.
+
+
The way this differs from the behavior of spp is that uspp actually encodes &
+decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
+DCT similar to MJPEG.
+
+
This filter is only available in ffmpeg version 4.4 or earlier.
+
+
The filter accepts the following options:
+
+
+- quality
+Set quality. This option defines the number of levels for averaging. It accepts
+an integer in the range 0-8. If set to 0, the filter will have no
+effect. A value of 8 means the higher quality. For each increment of
+that value the speed drops by a factor of approximately 2. Default value is
+3.
+
+- qp
+Force a constant quantization parameter. If not set, the filter will use the QP
+from the video stream (if available).
+
+- codec
+Use specified codec instead of snow.
+
+
+
+
+
39.266 v360
+
+
Convert 360 videos between various formats.
+
+
The filter accepts the following options:
+
+
+- input
+- output
+Set format of the input/output video.
+
+Available formats:
+
+
+- ‘e’
+- ‘equirect’
+Equirectangular projection.
+
+- ‘c3x2’
+- ‘c6x1’
+- ‘c1x6’
+Cubemap with 3x2/6x1/1x6 layout.
+
+Format specific options:
+
+
+- in_pad
+- out_pad
+Set padding proportion for the input/output cubemap. Values in decimals.
+
+Example values:
+
+- ‘0’
+No padding.
+
- ‘0.01’
+1% of face is padding. For example, with 1920x1280 resolution face size would be 640x640 and padding would be 3 pixels from each side. (640 * 0.01 = 6 pixels)
+
+
+Default value is ‘0’.
+Maximum value is ‘0.1’.
+
+- fin_pad
+- fout_pad
+Set fixed padding for the input/output cubemap. Values in pixels.
+
+Default value is ‘0’. If greater than zero it overrides other padding options.
+
+- in_forder
+- out_forder
+Set order of faces for the input/output cubemap. Choose one direction for each position.
+
+Designation of directions:
+
+- ‘r’
+right
+
- ‘l’
+left
+
- ‘u’
+up
+
- ‘d’
+down
+
- ‘f’
+forward
+
- ‘b’
+back
+
+
+Default value is ‘rludfb’.
+
+- in_frot
+- out_frot
+Set rotation of faces for the input/output cubemap. Choose one angle for each position.
+
+Designation of angles:
+
+- ‘0’
+0 degrees clockwise
+
- ‘1’
+90 degrees clockwise
+
- ‘2’
+180 degrees clockwise
+
- ‘3’
+270 degrees clockwise
+
+
+Default value is ‘000000’.
+
+
+- ‘eac’
+Equi-Angular Cubemap.
+
+- ‘flat’
+- ‘gnomonic’
+- ‘rectilinear’
+Regular video.
+
+Format specific options:
+
+- h_fov
+- v_fov
+- d_fov
+Set output horizontal/vertical/diagonal field of view. Values in degrees.
+
+If diagonal field of view is set it overrides horizontal and vertical field of view.
+
+- ih_fov
+- iv_fov
+- id_fov
+Set input horizontal/vertical/diagonal field of view. Values in degrees.
+
+If diagonal field of view is set it overrides horizontal and vertical field of view.
+
+
+- ‘dfisheye’
+Dual fisheye.
+
+Format specific options:
+
+- h_fov
+- v_fov
+- d_fov
+Set output horizontal/vertical/diagonal field of view. Values in degrees.
+
+If diagonal field of view is set it overrides horizontal and vertical field of view.
+
+- ih_fov
+- iv_fov
+- id_fov
+Set input horizontal/vertical/diagonal field of view. Values in degrees.
+
+If diagonal field of view is set it overrides horizontal and vertical field of view.
+
+
+- ‘barrel’
+- ‘fb’
+- ‘barrelsplit’
+Facebook’s 360 formats.
+
+- ‘sg’
+Stereographic format.
+
+Format specific options:
+
+- h_fov
+- v_fov
+- d_fov
+Set output horizontal/vertical/diagonal field of view. Values in degrees.
+
+If diagonal field of view is set it overrides horizontal and vertical field of view.
+
+- ih_fov
+- iv_fov
+- id_fov
+Set input horizontal/vertical/diagonal field of view. Values in degrees.
+
+If diagonal field of view is set it overrides horizontal and vertical field of view.
+
+
+- ‘mercator’
+Mercator format.
+
+- ‘ball’
+Ball format, gives significant distortion toward the back.
+
+- ‘hammer’
+Hammer-Aitoff map projection format.
+
+- ‘sinusoidal’
+Sinusoidal map projection format.
+
+- ‘fisheye’
+Fisheye projection.
+
+Format specific options:
+
+- h_fov
+- v_fov
+- d_fov
+Set output horizontal/vertical/diagonal field of view. Values in degrees.
+
+If diagonal field of view is set it overrides horizontal and vertical field of view.
+
+- ih_fov
+- iv_fov
+- id_fov
+Set input horizontal/vertical/diagonal field of view. Values in degrees.
+
+If diagonal field of view is set it overrides horizontal and vertical field of view.
+
+
+- ‘pannini’
+Pannini projection.
+
+Format specific options:
+
+- h_fov
+Set output pannini parameter.
+
+- ih_fov
+Set input pannini parameter.
+
+
+- ‘cylindrical’
+Cylindrical projection.
+
+Format specific options:
+
+- h_fov
+- v_fov
+- d_fov
+Set output horizontal/vertical/diagonal field of view. Values in degrees.
+
+If diagonal field of view is set it overrides horizontal and vertical field of view.
+
+- ih_fov
+- iv_fov
+- id_fov
+Set input horizontal/vertical/diagonal field of view. Values in degrees.
+
+If diagonal field of view is set it overrides horizontal and vertical field of view.
+
+
+- ‘perspective’
+Perspective projection. (output only)
+
+Format specific options:
+
+- v_fov
+Set perspective parameter.
+
+
+- ‘tetrahedron’
+Tetrahedron projection.
+
+- ‘tsp’
+Truncated square pyramid projection.
+
+- ‘he’
+- ‘hequirect’
+Half equirectangular projection.
+
+- ‘equisolid’
+Equisolid format.
+
+Format specific options:
+
+- h_fov
+- v_fov
+- d_fov
+Set output horizontal/vertical/diagonal field of view. Values in degrees.
+
+If diagonal field of view is set it overrides horizontal and vertical field of view.
+
+- ih_fov
+- iv_fov
+- id_fov
+Set input horizontal/vertical/diagonal field of view. Values in degrees.
+
+If diagonal field of view is set it overrides horizontal and vertical field of view.
+
+
+- ‘og’
+Orthographic format.
+
+Format specific options:
+
+- h_fov
+- v_fov
+- d_fov
+Set output horizontal/vertical/diagonal field of view. Values in degrees.
+
+If diagonal field of view is set it overrides horizontal and vertical field of view.
+
+- ih_fov
+- iv_fov
+- id_fov
+Set input horizontal/vertical/diagonal field of view. Values in degrees.
+
+If diagonal field of view is set it overrides horizontal and vertical field of view.
+
+
+- ‘octahedron’
+Octahedron projection.
+
+- ‘cylindricalea’
+Cylindrical Equal Area projection.
+
+
+- interp
+Set interpolation method.
+Note: more complex interpolation methods require much more memory to run.
+
+Available methods:
+
+
+- ‘near’
+- ‘nearest’
+Nearest neighbour.
+
- ‘line’
+- ‘linear’
+Bilinear interpolation.
+
- ‘lagrange9’
+Lagrange9 interpolation.
+
- ‘cube’
+- ‘cubic’
+Bicubic interpolation.
+
- ‘lanc’
+- ‘lanczos’
+Lanczos interpolation.
+
- ‘sp16’
+- ‘spline16’
+Spline16 interpolation.
+
- ‘gauss’
+- ‘gaussian’
+Gaussian interpolation.
+
- ‘mitchell’
+Mitchell interpolation.
+
+
+Default value is ‘line’.
+
+- w
+- h
+Set the output video resolution.
+
+Default resolution depends on formats.
+
+- in_stereo
+- out_stereo
+Set the input/output stereo format.
+
+
+- ‘2d’
+2D mono
+
- ‘sbs’
+Side by side
+
- ‘tb’
+Top bottom
+
+
+Default value is ‘2d’ for input and output format.
+
+- yaw
+- pitch
+- roll
+Set rotation for the output video. Values in degrees.
+
+- rorder
+Set rotation order for the output video. Choose one item for each position.
+
+
+- ‘y, Y’
+yaw
+
- ‘p, P’
+pitch
+
- ‘r, R’
+roll
+
+
+Default value is ‘ypr’.
+
+- h_flip
+- v_flip
+- d_flip
+Flip the output video horizontally(swaps left-right)/vertically(swaps up-down)/in-depth(swaps back-forward). Boolean values.
+
+- ih_flip
+- iv_flip
+Set if input video is flipped horizontally/vertically. Boolean values.
+
+- in_trans
+Set if input video is transposed. Boolean value, by default disabled.
+
+- out_trans
+Set if output video needs to be transposed. Boolean value, by default disabled.
+
+- h_offset
+- v_offset
+Set output horizontal/vertical off-axis offset. Default is set to 0.
+Allowed range is from -1 to 1.
+
+- alpha_mask
+Build mask in alpha plane for all unmapped pixels by marking them fully transparent. Boolean value, by default disabled.
+
+- reset_rot
+Reset rotation of output video. Boolean value, by default disabled.
+
+
+
+
+
39.266.1 Examples
+
+
+- Convert equirectangular video to cubemap with 3x2 layout and 1% padding using bicubic interpolation:
+
+
ffmpeg -i input.mkv -vf v360=e:c3x2:cubic:out_pad=0.01 output.mkv
+
- Extract back view of Equi-Angular Cubemap:
+
+
ffmpeg -i input.mkv -vf v360=eac:flat:yaw=180 output.mkv
+
- Convert transposed and horizontally flipped Equi-Angular Cubemap in side-by-side stereo format to equirectangular top-bottom stereo format:
+
+
v360=eac:equirect:in_stereo=sbs:in_trans=1:ih_flip=1:out_stereo=tb
+
+
+
+
+
39.266.2 Commands
+
+
This filter supports subset of above options as commands.
+
+
+
+
+
39.267 vaguedenoiser
+
+
Apply a wavelet based denoiser.
+
+
It transforms each frame from the video input into the wavelet domain,
+using Cohen-Daubechies-Feauveau 9/7. Then it applies some filtering to
+the obtained coefficients. It does an inverse wavelet transform after.
+Due to wavelet properties, it should give a nice smoothed result, and
+reduced noise, without blurring picture features.
+
+
This filter accepts the following options:
+
+
+- threshold
+The filtering strength. The higher, the more filtered the video will be.
+Hard thresholding can use a higher threshold than soft thresholding
+before the video looks overfiltered. Default value is 2.
+
+- method
+The filtering method the filter will use.
+
+It accepts the following values:
+
+- ‘hard’
+All values under the threshold will be zeroed.
+
+- ‘soft’
+All values under the threshold will be zeroed. All values above will be
+reduced by the threshold.
+
+- ‘garrote’
+Scales or nullifies coefficients - intermediary between (more) soft and
+(less) hard thresholding.
+
+
+Default is garrote.
+
+- nsteps
+Number of times, the wavelet will decompose the picture. Picture can’t
+be decomposed beyond a particular point (typically, 8 for a 640x480
+frame - as 2^9 = 512 > 480). Valid values are integers between 1 and 32. Default value is 6.
+
+- percent
+Partial of full denoising (limited coefficients shrinking), from 0 to 100. Default value is 85.
+
+- planes
+A list of the planes to process. By default all planes are processed.
+
+- type
+The threshold type the filter will use.
+
+It accepts the following values:
+
+- ‘universal’
+Threshold used is same for all decompositions.
+
+- ‘bayes’
+Threshold used depends also on each decomposition coefficients.
+
+
+Default is universal.
+
+
+
+
+
39.268 varblur
+
Apply variable blur filter by using 2nd video stream to set blur radius.
+The 2nd stream must have the same dimensions.
+
+
This filter accepts the following options:
+
+
+- min_r
+Set min allowed radius. Allowed range is from 0 to 254. Default is 0.
+
- max_r
+Set max allowed radius. Allowed range is from 1 to 255. Default is 8.
+
- planes
+Set which planes to process. By default, all are used.
+
+
+
The varblur filter also supports the framesync options.
+
+
+
+
39.268.1 Commands
+
+
This filter supports all the above options as commands.
+
+
+
+
+
39.269 vectorscope
+
+
Display 2 color component values in the two dimensional graph (which is called
+a vectorscope).
+
+
This filter accepts the following options:
+
+
+- mode, m
+Set vectorscope mode.
+
+It accepts the following values:
+
+- ‘gray’
+- ‘tint’
+Gray values are displayed on graph, higher brightness means more pixels have
+same component color value on location in graph. This is the default mode.
+
+- ‘color’
+Gray values are displayed on graph. Surrounding pixels values which are not
+present in video frame are drawn in gradient of 2 color components which are
+set by option x and y. The 3rd color component is static.
+
+- ‘color2’
+Actual color components values present in video frame are displayed on graph.
+
+- ‘color3’
+Similar as color2 but higher frequency of same values x and y
+on graph increases value of another color component, which is luminance by
+default values of x and y.
+
+- ‘color4’
+Actual colors present in video frame are displayed on graph. If two different
+colors map to same position on graph then color with higher value of component
+not present in graph is picked.
+
+- ‘color5’
+Gray values are displayed on graph. Similar to color but with 3rd color
+component picked from radial gradient.
+
+
+- x
+Set which color component will be represented on X-axis. Default is 1.
+
+- y
+Set which color component will be represented on Y-axis. Default is 2.
+
+- intensity, i
+Set intensity, used by modes: gray, color, color3 and color5 for increasing brightness
+of color component which represents frequency of (X, Y) location in graph.
+
+- envelope, e
+
+- ‘none’
+No envelope, this is default.
+
+- ‘instant’
+Instant envelope, even darkest single pixel will be clearly highlighted.
+
+- ‘peak’
+Hold maximum and minimum values presented in graph over time. This way you
+can still spot out of range values without constantly looking at vectorscope.
+
+- ‘peak+instant’
+Peak and instant envelope combined together.
+
+
+- graticule, g
+Set what kind of graticule to draw.
+
+- ‘none’
+- ‘green’
+- ‘color’
+- ‘invert’
+
+
+- opacity, o
+Set graticule opacity.
+
+- flags, f
+Set graticule flags.
+
+
+- ‘white’
+Draw graticule for white point.
+
+- ‘black’
+Draw graticule for black point.
+
+- ‘name’
+Draw color points short names.
+
+
+- bgopacity, b
+Set background opacity.
+
+- lthreshold, l
+Set low threshold for color component not represented on X or Y axis.
+Values lower than this value will be ignored. Default is 0.
+Note this value is multiplied with actual max possible value one pixel component
+can have. So for 8-bit input and low threshold value of 0.1 actual threshold
+is 0.1 * 255 = 25.
+
+- hthreshold, h
+Set high threshold for color component not represented on X or Y axis.
+Values higher than this value will be ignored. Default is 1.
+Note this value is multiplied with actual max possible value one pixel component
+can have. So for 8-bit input and high threshold value of 0.9 actual threshold
+is 0.9 * 255 = 230.
+
+- colorspace, c
+Set what kind of colorspace to use when drawing graticule.
+
+- ‘auto’
+- ‘601’
+- ‘709’
+
+Default is auto.
+
+- tint0, t0
+- tint1, t1
+Set color tint for gray/tint vectorscope mode. By default both options are zero.
+This means no tint, and output will remain gray.
+
+
+
+
+
39.270 vidstabdetect
+
+
Analyze video stabilization/deshaking. Perform pass 1 of 2, see
+vidstabtransform for pass 2.
+
+
This filter generates a file with relative translation and rotation
+transform information about subsequent frames, which is then used by
+the vidstabtransform filter.
+
+
To enable compilation of this filter you need to configure FFmpeg with
+--enable-libvidstab.
+
+
This filter accepts the following options:
+
+
+- result
+Set the path to the file used to write the transforms information.
+Default value is transforms.trf.
+
+- shakiness
+Set how shaky the video is and how quick the camera is. It accepts an
+integer in the range 1-10, a value of 1 means little shakiness, a
+value of 10 means strong shakiness. Default value is 5.
+
+- accuracy
+Set the accuracy of the detection process. It must be a value in the
+range 1-15. A value of 1 means low accuracy, a value of 15 means high
+accuracy. Default value is 15.
+
+- stepsize
+Set stepsize of the search process. The region around minimum is
+scanned with 1 pixel resolution. Default value is 6.
+
+- mincontrast
+Set minimum contrast. Below this value a local measurement field is
+discarded. Must be a floating point value in the range 0-1. Default
+value is 0.3.
+
+- tripod
+Set reference frame number for tripod mode.
+
+If enabled, the motion of the frames is compared to a reference frame
+in the filtered stream, identified by the specified number. The idea
+is to compensate all movements in a more-or-less static scene and keep
+the camera view absolutely still.
+
+If set to 0, it is disabled. The frames are counted starting from 1.
+
+- show
+Show fields and transforms in the resulting frames. It accepts an
+integer in the range 0-2. Default value is 0, which disables any
+visualization.
+
+
+
+
+
39.270.1 Examples
+
+
+- Use default values:
+
+
+
- Analyze strongly shaky movie and put the results in file
+mytransforms.trf:
+
+
vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
+
- Visualize the result of internal transformations in the resulting
+video:
+
+
+
- Analyze a video with medium shakiness using
ffmpeg:
+
+
ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
+
+
+
+
+
+
+
39.272 vflip
+
+
Flip the input video vertically.
+
+
For example, to vertically flip a video with ffmpeg:
+
+
ffmpeg -i in.avi -vf "vflip" out.avi
+
+
+
+
+
39.273 vfrdet
+
+
Detect variable frame rate video.
+
+
This filter tries to detect if the input is variable or constant frame rate.
+
+
At end it will output number of frames detected as having variable delta pts,
+and ones with constant delta pts.
+If there was frames with variable delta, than it will also show min, max and
+average delta encountered.
+
+
+
+
39.274 vibrance
+
+
Boost or alter saturation.
+
+
The filter accepts the following options:
+
+- intensity
+Set strength of boost if positive value or strength of alter if negative value.
+Default is 0. Allowed range is from -2 to 2.
+
+- rbal
+Set the red balance. Default is 1. Allowed range is from -10 to 10.
+
+- gbal
+Set the green balance. Default is 1. Allowed range is from -10 to 10.
+
+- bbal
+Set the blue balance. Default is 1. Allowed range is from -10 to 10.
+
+- rlum
+Set the red luma coefficient.
+
+- glum
+Set the green luma coefficient.
+
+- blum
+Set the blue luma coefficient.
+
+- alternate
+If intensity is negative and this is set to 1, colors will change,
+otherwise colors will be less saturated, more towards gray.
+
+
+
+
+
39.274.1 Commands
+
+
This filter supports the all above options as commands.
+
+
+
+
+
39.275 vif
+
+
Obtain the average VIF (Visual Information Fidelity) between two input videos.
+
+
This filter takes two input videos.
+
+
Both input videos must have the same resolution and pixel format for
+this filter to work correctly. Also it assumes that both inputs
+have the same number of frames, which are compared one by one.
+
+
The obtained average VIF score is printed through the logging system.
+
+
The filter stores the calculated VIF score of each frame.
+
+
This filter also supports the framesync options.
+
+
In the below example the input file main.mpg being processed is compared
+with the reference file ref.mpg.
+
+
+
ffmpeg -i main.mpg -i ref.mpg -lavfi vif -f null -
+
+
+
+
+
39.276 vignette
+
+
Make or reverse a natural vignetting effect.
+
+
The filter accepts the following options:
+
+
+- angle, a
+Set lens angle expression as a number of radians.
+
+The value is clipped in the [0,PI/2] range.
+
+Default value: "PI/5"
+
+- x0
+- y0
+Set center coordinates expressions. Respectively "w/2" and "h/2"
+by default.
+
+- mode
+Set forward/backward mode.
+
+Available modes are:
+
+- ‘forward’
+The larger the distance from the central point, the darker the image becomes.
+
+- ‘backward’
+The larger the distance from the central point, the brighter the image becomes.
+This can be used to reverse a vignette effect, though there is no automatic
+detection to extract the lens angle and other settings (yet). It can
+also be used to create a burning effect.
+
+
+Default value is ‘forward’.
+
+- eval
+Set evaluation mode for the expressions (angle, x0, y0).
+
+It accepts the following values:
+
+- ‘init’
+Evaluate expressions only once during the filter initialization.
+
+- ‘frame’
+Evaluate expressions for each incoming frame. This is way slower than the
+‘init’ mode since it requires all the scalers to be re-computed, but it
+allows advanced dynamic expressions.
+
+
+Default value is ‘init’.
+
+- dither
+Set dithering to reduce the circular banding effects. Default is 1
+(enabled).
+
+- aspect
+Set vignette aspect. This setting allows one to adjust the shape of the vignette.
+Setting this value to the SAR of the input will make a rectangular vignetting
+following the dimensions of the video.
+
+Default is 1/1.
+
+
+
+
+
39.276.1 Expressions
+
+
The alpha, x0 and y0 expressions can contain the
+following parameters.
+
+
+- w
+- h
+input width and height
+
+- n
+the number of input frame, starting from 0
+
+- pts
+the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
+TB units, NAN if undefined
+
+- r
+frame rate of the input video, NAN if the input frame rate is unknown
+
+- t
+the PTS (Presentation TimeStamp) of the filtered video frame,
+expressed in seconds, NAN if undefined
+
+- tb
+time base of the input video
+
+
+
+
+
+
39.276.2 Examples
+
+
+- Apply simple strong vignetting effect:
+
+
+
- Make a flickering vignetting:
+
+
vignette='PI/4+random(1)*PI/50':eval=frame
+
+
+
+
+
+
39.277 vmafmotion
+
+
Obtain the average VMAF motion score of a video.
+It is one of the component metrics of VMAF.
+
+
The obtained average motion score is printed through the logging system.
+
+
The filter accepts the following options:
+
+
+- stats_file
+If specified, the filter will use the named file to save the motion score of
+each frame with respect to the previous frame.
+When filename equals "-" the data is sent to standard output.
+
+
+
Example:
+
+
ffmpeg -i ref.mpg -vf vmafmotion -f null -
+
+
+
+
+
39.278 vstack
+
Stack input videos vertically.
+
+
All streams must be of same pixel format and of same width.
+
+
Note that this filter is faster than using overlay and pad filter
+to create same output.
+
+
The filter accepts the following options:
+
+
+- inputs
+Set number of input streams. Default is 2.
+
+- shortest
+If set to 1, force the output to terminate when the shortest input
+terminates. Default value is 0.
+
+
+
+
+
39.279 w3fdif
+
+
Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
+Deinterlacing Filter").
+
+
Based on the process described by Martin Weston for BBC R&D, and
+implemented based on the de-interlace algorithm written by Jim
+Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
+uses filter coefficients calculated by BBC R&D.
+
+
This filter uses field-dominance information in frame to decide which
+of each pair of fields to place first in the output.
+If it gets it wrong use setfield filter before w3fdif filter.
+
+
There are two sets of filter coefficients, so called "simple"
+and "complex". Which set of filter coefficients is used can
+be set by passing an optional parameter:
+
+
+- filter
+Set the interlacing filter coefficients. Accepts one of the following values:
+
+
+- ‘simple’
+Simple filter coefficient set.
+
- ‘complex’
+More-complex filter coefficient set.
+
+Default value is ‘complex’.
+
+- mode
+The interlacing mode to adopt. It accepts one of the following values:
+
+
+- frame
+Output one frame for each frame.
+
- field
+Output one frame for each field.
+
+
+The default value is field.
+
+- parity
+The picture field parity assumed for the input interlaced video. It accepts one
+of the following values:
+
+
+- tff
+Assume the top field is first.
+
- bff
+Assume the bottom field is first.
+
- auto
+Enable automatic detection of field parity.
+
+
+The default value is auto.
+If the interlacing is unknown or the decoder does not export this information,
+top field first will be assumed.
+
+- deint
+Specify which frames to deinterlace. Accepts one of the following values:
+
+
+- ‘all’
+Deinterlace all frames,
+
- ‘interlaced’
+Only deinterlace frames marked as interlaced.
+
+
+Default value is ‘all’.
+
+
+
+
+
39.279.1 Commands
+
This filter supports same commands as options.
+
+
+
+
+
+
39.281 weave, doubleweave
+
+
The weave takes a field-based video input and join
+each two sequential fields into single frame, producing a new double
+height clip with half the frame rate and half the frame count.
+
+
The doubleweave works same as weave but without
+halving frame rate and frame count.
+
+
It accepts the following option:
+
+
+- first_field
+Set first field. Available values are:
+
+
+- ‘top, t’
+Set the frame as top-field-first.
+
+- ‘bottom, b’
+Set the frame as bottom-field-first.
+
+
+
+
+
+
39.281.1 Examples
+
+
+- Interlace video using select and separatefields filter:
+
+
separatefields,select=eq(mod(n,4),0)+eq(mod(n,4),3),weave
+
+
+
+
+
+
39.282 xbr
+
Apply the xBR high-quality magnification filter which is designed for pixel
+art. It follows a set of edge-detection rules, see
+https://forums.libretro.com/t/xbr-algorithm-tutorial/123.
+
+
It accepts the following option:
+
+
+- n
+Set the scaling dimension: 2 for 2xBR, 3 for
+3xBR and 4 for 4xBR.
+Default is 3.
+
+
+
+
+
39.283 xcorrelate
+
Apply normalized cross-correlation between first and second input video stream.
+
+
Second input video stream dimensions must be lower than first input video stream.
+
+
The filter accepts the following options:
+
+
+- planes
+Set which planes to process.
+
+- secondary
+Set which secondary video frames will be processed from second input video stream,
+can be first or all. Default is all.
+
+
+
The xcorrelate filter also supports the framesync options.
+
+
+
+
39.284 xfade
+
+
Apply cross fade from one input video stream to another input video stream.
+The cross fade is applied for specified duration.
+
+
Both inputs must be constant frame-rate and have the same resolution, pixel format,
+frame rate and timebase.
+
+
The filter accepts the following options:
+
+
+- transition
+Set one of available transition effects:
+
+
+- ‘custom’
+- ‘fade’
+- ‘wipeleft’
+- ‘wiperight’
+- ‘wipeup’
+- ‘wipedown’
+- ‘slideleft’
+- ‘slideright’
+- ‘slideup’
+- ‘slidedown’
+- ‘circlecrop’
+- ‘rectcrop’
+- ‘distance’
+- ‘fadeblack’
+- ‘fadewhite’
+- ‘radial’
+- ‘smoothleft’
+- ‘smoothright’
+- ‘smoothup’
+- ‘smoothdown’
+- ‘circleopen’
+- ‘circleclose’
+- ‘vertopen’
+- ‘vertclose’
+- ‘horzopen’
+- ‘horzclose’
+- ‘dissolve’
+- ‘pixelize’
+- ‘diagtl’
+- ‘diagtr’
+- ‘diagbl’
+- ‘diagbr’
+- ‘hlslice’
+- ‘hrslice’
+- ‘vuslice’
+- ‘vdslice’
+- ‘hblur’
+- ‘fadegrays’
+- ‘wipetl’
+- ‘wipetr’
+- ‘wipebl’
+- ‘wipebr’
+- ‘squeezeh’
+- ‘squeezev’
+- ‘zoomin’
+- ‘fadefast’
+- ‘fadeslow’
+- ‘hlwind’
+- ‘hrwind’
+- ‘vuwind’
+- ‘vdwind’
+
+Default transition effect is fade.
+
+- duration
+Set cross fade duration in seconds.
+Range is 0 to 60 seconds.
+Default duration is 1 second.
+
+- offset
+Set cross fade start relative to first input stream in seconds.
+Default offset is 0.
+
+- expr
+Set expression for custom transition effect.
+
+The expressions can use the following variables and functions:
+
+
+- X
+- Y
+The coordinates of the current sample.
+
+- W
+- H
+The width and height of the image.
+
+- P
+Progress of transition effect.
+
+- PLANE
+Currently processed plane.
+
+- A
+Return value of first input at current location and plane.
+
+- B
+Return value of second input at current location and plane.
+
+- a0(x, y)
+- a1(x, y)
+- a2(x, y)
+- a3(x, y)
+Return the value of the pixel at location (x,y) of the
+first/second/third/fourth component of first input.
+
+- b0(x, y)
+- b1(x, y)
+- b2(x, y)
+- b3(x, y)
+Return the value of the pixel at location (x,y) of the
+first/second/third/fourth component of second input.
+
+
+
+
+
+
39.284.1 Examples
+
+
+- Cross fade from one input video to another input video, with fade transition and duration of transition
+of 2 seconds starting at offset of 5 seconds:
+
+
ffmpeg -i first.mp4 -i second.mp4 -filter_complex xfade=transition=fade:duration=2:offset=5 output.mp4
+
+
+
+
+
+
+
39.286 xstack
+
Stack video inputs into custom layout.
+
+
All streams must be of same pixel format.
+
+
The filter accepts the following options:
+
+
+- inputs
+Set number of input streams. Default is 2.
+
+- layout
+Specify layout of inputs.
+This option requires the desired layout configuration to be explicitly set by the user.
+This sets position of each video input in output. Each input
+is separated by ’|’.
+The first number represents the column, and the second number represents the row.
+Numbers start at 0 and are separated by ’_’. Optionally one can use wX and hX,
+where X is video input from which to take width or height.
+Multiple values can be used when separated by ’+’. In such
+case values are summed together.
+
+Note that if inputs are of different sizes gaps may appear, as not all of
+the output video frame will be filled. Similarly, videos can overlap each
+other if their position doesn’t leave enough space for the full frame of
+adjoining videos.
+
+For 2 inputs, a default layout of 0_0|w0_0 (equivalent to
+grid=2x1) is set. In all other cases, a layout or a grid must be set by
+the user. Either grid or layout can be specified at a time.
+Specifying both will result in an error.
+
+- grid
+Specify a fixed size grid of inputs.
+This option is used to create a fixed size grid of the input streams. Set the
+grid size in the form COLUMNSxROWS. There must be ROWS * COLUMNS
+input streams and they will be arranged as a grid with ROWS rows and
+COLUMNS columns. When using this option, each input stream within a row
+must have the same height and all the rows must have the same width.
+
+If grid is set, then inputs option is ignored and is implicitly
+set to ROWS * COLUMNS.
+
+For 2 inputs, a default grid of 2x1 (equivalent to
+layout=0_0|w0_0) is set. In all other cases, a layout or a grid must be
+set by the user. Either grid or layout can be specified at a time.
+Specifying both will result in an error.
+
+- shortest
+If set to 1, force the output to terminate when the shortest input
+terminates. Default value is 0.
+
+- fill
+If set to valid color, all unused pixels will be filled with that color.
+By default fill is set to none, so it is disabled.
+
+
+
+
+
39.286.1 Examples
+
+
+- Display 4 inputs into 2x2 grid.
+
+
Layout:
+
+
input1(0, 0) | input3(w0, 0)
+input2(0, h0) | input4(w0, h0)
+
+
xstack=inputs=4:layout=0_0|0_h0|w0_0|w0_h0
+
Note that if inputs are of different sizes, gaps or overlaps may occur.
+
+ - Display 4 inputs into 1x4 grid.
+
+
Layout:
+
+
input1(0, 0)
+input2(0, h0)
+input3(0, h0+h1)
+input4(0, h0+h1+h2)
+
+
xstack=inputs=4:layout=0_0|0_h0|0_h0+h1|0_h0+h1+h2
+
Note that if inputs are of different widths, unused space will appear.
+
+ - Display 9 inputs into 3x3 grid.
+
+
Layout:
+
+
input1(0, 0) | input4(w0, 0) | input7(w0+w3, 0)
+input2(0, h0) | input5(w0, h0) | input8(w0+w3, h0)
+input3(0, h0+h1) | input6(w0, h0+h1) | input9(w0+w3, h0+h1)
+
+
xstack=inputs=9:layout=0_0|0_h0|0_h0+h1|w0_0|w0_h0|w0_h0+h1|w0+w3_0|w0+w3_h0|w0+w3_h0+h1
+
Note that if inputs are of different sizes, gaps or overlaps may occur.
+
+ - Display 16 inputs into 4x4 grid.
+
+
Layout:
+
+
input1(0, 0) | input5(w0, 0) | input9 (w0+w4, 0) | input13(w0+w4+w8, 0)
+input2(0, h0) | input6(w0, h0) | input10(w0+w4, h0) | input14(w0+w4+w8, h0)
+input3(0, h0+h1) | input7(w0, h0+h1) | input11(w0+w4, h0+h1) | input15(w0+w4+w8, h0+h1)
+input4(0, h0+h1+h2)| input8(w0, h0+h1+h2)| input12(w0+w4, h0+h1+h2)| input16(w0+w4+w8, h0+h1+h2)
+
+
xstack=inputs=16:layout=0_0|0_h0|0_h0+h1|0_h0+h1+h2|w0_0|w0_h0|w0_h0+h1|w0_h0+h1+h2|w0+w4_0|
+w0+w4_h0|w0+w4_h0+h1|w0+w4_h0+h1+h2|w0+w4+w8_0|w0+w4+w8_h0|w0+w4+w8_h0+h1|w0+w4+w8_h0+h1+h2
+
Note that if inputs are of different sizes, gaps or overlaps may occur.
+
+
+
+
+
+
+
39.287 yadif
+
+
Deinterlace the input video ("yadif" means "yet another deinterlacing
+filter").
+
+
It accepts the following parameters:
+
+
+
+- mode
+The interlacing mode to adopt. It accepts one of the following values:
+
+
+- 0, send_frame
+Output one frame for each frame.
+
- 1, send_field
+Output one frame for each field.
+
- 2, send_frame_nospatial
+Like send_frame, but it skips the spatial interlacing check.
+
- 3, send_field_nospatial
+Like send_field, but it skips the spatial interlacing check.
+
+
+The default value is send_frame.
+
+- parity
+The picture field parity assumed for the input interlaced video. It accepts one
+of the following values:
+
+
+- 0, tff
+Assume the top field is first.
+
- 1, bff
+Assume the bottom field is first.
+
- -1, auto
+Enable automatic detection of field parity.
+
+
+The default value is auto.
+If the interlacing is unknown or the decoder does not export this information,
+top field first will be assumed.
+
+- deint
+Specify which frames to deinterlace. Accepts one of the following
+values:
+
+
+- 0, all
+Deinterlace all frames.
+
- 1, interlaced
+Only deinterlace frames marked as interlaced.
+
+
+The default value is all.
+
+
+
+
+
39.288 yadif_cuda
+
+
Deinterlace the input video using the yadif algorithm, but implemented
+in CUDA so that it can work as part of a GPU accelerated pipeline with nvdec
+and/or nvenc.
+
+
It accepts the following parameters:
+
+
+
+- mode
+The interlacing mode to adopt. It accepts one of the following values:
+
+
+- 0, send_frame
+Output one frame for each frame.
+
- 1, send_field
+Output one frame for each field.
+
- 2, send_frame_nospatial
+Like send_frame, but it skips the spatial interlacing check.
+
- 3, send_field_nospatial
+Like send_field, but it skips the spatial interlacing check.
+
+
+The default value is send_frame.
+
+- parity
+The picture field parity assumed for the input interlaced video. It accepts one
+of the following values:
+
+
+- 0, tff
+Assume the top field is first.
+
- 1, bff
+Assume the bottom field is first.
+
- -1, auto
+Enable automatic detection of field parity.
+
+
+The default value is auto.
+If the interlacing is unknown or the decoder does not export this information,
+top field first will be assumed.
+
+- deint
+Specify which frames to deinterlace. Accepts one of the following
+values:
+
+
+- 0, all
+Deinterlace all frames.
+
- 1, interlaced
+Only deinterlace frames marked as interlaced.
+
+
+The default value is all.
+
+
+
+
+
39.289 yaepblur
+
+
Apply blur filter while preserving edges ("yaepblur" means "yet another edge preserving blur filter").
+The algorithm is described in
+"J. S. Lee, Digital image enhancement and noise filtering by use of local statistics, IEEE Trans. Pattern Anal. Mach. Intell. PAMI-2, 1980."
+
+
It accepts the following parameters:
+
+
+- radius, r
+Set the window radius. Default value is 3.
+
+- planes, p
+Set which planes to filter. Default is only the first plane.
+
+- sigma, s
+Set blur strength. Default value is 128.
+
+
+
+
+
39.289.1 Commands
+
This filter supports same commands as options.
+
+
+
+
+
39.290 zoompan
+
+
Apply Zoom & Pan effect.
+
+
This filter accepts the following options:
+
+
+- zoom, z
+Set the zoom expression. Range is 1-10. Default is 1.
+
+- x
+- y
+Set the x and y expression. Default is 0.
+
+- d
+Set the duration expression in number of frames.
+This sets for how many number of frames effect will last for
+single input image. Default is 90.
+
+- s
+Set the output image size, default is ’hd720’.
+
+- fps
+Set the output frame rate, default is ’25’.
+
+
+
Each expression can contain the following constants:
+
+
+- in_w, iw
+Input width.
+
+- in_h, ih
+Input height.
+
+- out_w, ow
+Output width.
+
+- out_h, oh
+Output height.
+
+- in
+Input frame count.
+
+- on
+Output frame count.
+
+- in_time, it
+The input timestamp expressed in seconds. It’s NAN if the input timestamp is unknown.
+
+- out_time, time, ot
+The output timestamp expressed in seconds.
+
+- x
+- y
+Last calculated ’x’ and ’y’ position from ’x’ and ’y’ expression
+for current input frame.
+
+- px
+- py
+’x’ and ’y’ of last output frame of previous input frame or 0 when there was
+not yet such frame (first input frame).
+
+- zoom
+Last calculated zoom from ’z’ expression for current input frame.
+
+- pzoom
+Last calculated zoom of last output frame of previous input frame.
+
+- duration
+Number of output frames for current input frame. Calculated from ’d’ expression
+for each input frame.
+
+- pduration
+number of output frames created for previous input frame
+
+- a
+Rational number: input width / input height
+
+- sar
+sample aspect ratio
+
+- dar
+display aspect ratio
+
+
+
+
+
+
39.290.1 Examples
+
+
+- Zoom in up to 1.5x and pan at same time to some spot near center of picture:
+
+
zoompan=z='min(zoom+0.0015,1.5)':d=700:x='if(gte(zoom,1.5),x,x+1/a)':y='if(gte(zoom,1.5),y,y+1)':s=640x360
+
- Zoom in up to 1.5x and pan always at center of picture:
+
+
zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
+
- Same as above but without pausing:
+
+
zoompan=z='min(max(zoom,pzoom)+0.0015,1.5)':d=1:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
+
- Zoom in 2x into center of picture only for the first second of the input video:
+
+
zoompan=z='if(between(in_time,0,1),2,1)':d=1:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
+
+
+
+
+
+
39.291 zscale
+
Scale (resize) the input video, using the z.lib library:
+https://github.com/sekrit-twc/zimg. To enable compilation of this
+filter, you need to configure FFmpeg with --enable-libzimg.
+
+
The zscale filter forces the output display aspect ratio to be the same
+as the input, by changing the output sample aspect ratio.
+
+
If the input image format is different from the format requested by
+the next filter, the zscale filter will convert the input to the
+requested format.
+
+
+
+
39.291.1 Options
+
The filter accepts the following options.
+
+
+- width, w
+- height, h
+Set the output video dimension expression. Default value is the input
+dimension.
+
+If the width or w value is 0, the input width is used for
+the output. If the height or h value is 0, the input height
+is used for the output.
+
+If one and only one of the values is -n with n >= 1, the zscale filter
+will use a value that maintains the aspect ratio of the input image,
+calculated from the other specified dimension. After that it will,
+however, make sure that the calculated dimension is divisible by n and
+adjust the value if necessary.
+
+If both values are -n with n >= 1, the behavior will be identical to
+both values being set to 0 as previously detailed.
+
+See below for the list of accepted constants for use in the dimension
+expression.
+
+- size, s
+Set the video size. For the syntax of this option, check the
+(ffmpeg-utils)"Video size" section in the ffmpeg-utils manual.
+
+- dither, d
+Set the dither type.
+
+Possible values are:
+
+- none
+- ordered
+- random
+- error_diffusion
+
+
+Default is none.
+
+- filter, f
+Set the resize filter type.
+
+Possible values are:
+
+- point
+- bilinear
+- bicubic
+- spline16
+- spline36
+- lanczos
+
+
+Default is bilinear.
+
+- range, r
+Set the color range.
+
+Possible values are:
+
+- input
+- limited
+- full
+
+
+Default is same as input.
+
+- primaries, p
+Set the color primaries.
+
+Possible values are:
+
+- input
+- 709
+- unspecified
+- 170m
+- 240m
+- 2020
+
+
+Default is same as input.
+
+- transfer, t
+Set the transfer characteristics.
+
+Possible values are:
+
+- input
+- 709
+- unspecified
+- 601
+- linear
+- 2020_10
+- 2020_12
+- smpte2084
+- iec61966-2-1
+- arib-std-b67
+
+
+Default is same as input.
+
+- matrix, m
+Set the colorspace matrix.
+
+Possible value are:
+
+- input
+- 709
+- unspecified
+- 470bg
+- 170m
+- 2020_ncl
+- 2020_cl
+
+
+Default is same as input.
+
+- rangein, rin
+Set the input color range.
+
+Possible values are:
+
+- input
+- limited
+- full
+
+
+Default is same as input.
+
+- primariesin, pin
+Set the input color primaries.
+
+Possible values are:
+
+- input
+- 709
+- unspecified
+- 170m
+- 240m
+- 2020
+
+
+Default is same as input.
+
+- transferin, tin
+Set the input transfer characteristics.
+
+Possible values are:
+
+- input
+- 709
+- unspecified
+- 601
+- linear
+- 2020_10
+- 2020_12
+
+
+Default is same as input.
+
+- matrixin, min
+Set the input colorspace matrix.
+
+Possible value are:
+
+- input
+- 709
+- unspecified
+- 470bg
+- 170m
+- 2020_ncl
+- 2020_cl
+
+
+- chromal, c
+Set the output chroma location.
+
+Possible values are:
+
+- input
+- left
+- center
+- topleft
+- top
+- bottomleft
+- bottom
+
+
+- chromalin, cin
+Set the input chroma location.
+
+Possible values are:
+
+- input
+- left
+- center
+- topleft
+- top
+- bottomleft
+- bottom
+
+
+- npl
+Set the nominal peak luminance.
+
+- param_a
+Parameter A for scaling filters. Parameter "b" for bicubic, and the number of
+filter taps for lanczos.
+
+- param_b
+Parameter B for scaling filters. Parameter "c" for bicubic.
+
+
+
The values of the w and h options are expressions
+containing the following constants:
+
+
+- in_w
+- in_h
+The input width and height
+
+- iw
+- ih
+These are the same as in_w and in_h.
+
+- out_w
+- out_h
+The output (scaled) width and height
+
+- ow
+- oh
+These are the same as out_w and out_h
+
+- a
+The same as iw / ih
+
+- sar
+input sample aspect ratio
+
+- dar
+The input display aspect ratio. Calculated from (iw / ih) * sar.
+
+- hsub
+- vsub
+horizontal and vertical input chroma subsample values. For example for the
+pixel format "yuv422p" hsub is 2 and vsub is 1.
+
+- ohsub
+- ovsub
+horizontal and vertical output chroma subsample values. For example for the
+pixel format "yuv422p" hsub is 2 and vsub is 1.
+
+
+
+
+
39.291.2 Commands
+
+
This filter supports the following commands:
+
+- width, w
+- height, h
+Set the output video dimension expression.
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+
+
+
+
+
+