README.md

metadata

license: apache-2.0
datasets:
  - projectlosangeles/Godzilla-MIDI-Dataset
language:
  - en
tags:
  - Orpheus
  - MIDI
  - music-ai
  - music-transformer
  - SOTA
  - multi-instrumental
  - music

Orpheus Music Transformer

SOTA 8k multi-instrumental music transformer trained on 2.31M+ high-quality MIDIs

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Abstract

Project Los Angeles is very proud to present Orpheus Music Transformer, an efficient, SOTA transformer model for long-form, multi-instrumental music generation. At its core lies a 479 M-parameter autoregressive transformer equipped with Rotary Positional Embeddings (RoPE) and Flash Attention, enabling sequence lengths up to 8 k tokens—sufficient to capture extended musical structures. Trained for three epochs on 2.31 million high-quality MIDI tracks from the Godzilla dataset, our model employs a compact 3-token-per-note and 7-token-per-tri-chord encoding, plus a novel duration-and-velocity-last ordering to enhance expressivity. We leverage PyTorch’s bfloat16 precision and memory-efficient sparse-dense products for accelerated inference on CUDA, and provide a top-p sampling filter with adjustable temperature.

The Gradio interface empowers users to upload seed MIDI files or generate from scratch, tune prime/generation token counts, control randomness (temperature, top-p), and optionally append drums or natural “outro” tokens. Generated outputs appear in ten parallel batches with synchronized audio previews and piano-roll plots. Users can iteratively add or remove entire batches to sculpt a final composition, which is rendered back into MIDI and audio via an integrated SoundFont pipeline. Our release demonstrates a seamless blend of state-of-the-art model performance, efficient MIDI tokenization, and user-centric design, fostering rapid exploration of algorithmic composition.

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Models

Presented are two models:

Orpheus Music Transformer Model

This is a base model that is capable of music generation/continuation and notes/drums inpainting

Orpheus Bridge Music Transformer Model

This is an auxiliary model that is capable of seamless bridge inpainting/infilling in any music composition

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Live Hugging Face spaces demos

Orpheus Music Transformer

If you enjoyed any of the Orpheus Music Transformer demos, please star and duplicate. It helps a lot! 🤗

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Training dataset code

Models were trained on select HQ MIDIs from Godzilla MIDI Dataset

Please check out Orpheus Taining Dataset Maker notebook for details

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Models training code

Please check out Orpheus Music Transformer Maker code/notebook for details

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Project Los Angeles

Tegridy Code 2025