---
license: other
license_name: mix-directive-model-license
license_link: LICENSE.md
library_name: onnx
pipeline_tag: audio-to-audio
tags:
  - music-source-separation
  - stem-separation
  - mix-directive
---

# Mix Directive Stem Splitter (4-stem, v1)

The stem separation model used by the [Mix Directive](https://mixdirective.example) desktop
app. It splits a stereo mix into **drums**, **bass**, **other** and **vocals**.

**This model is proprietary.** It is published here only so the Mix Directive app can
download it on demand. Using it outside the app, redistributing it, or building on it is
not permitted: see [LICENSE.md](LICENSE.md).

## Files

| File | What it is | SHA-256 |
|---|---|---|
| `model_fp16.onnx` | the model (ONNX, fp16 weights, 56 MB) | `f45b4b79dd08b9e0237bd7420b735659b043edb25b572949dbb4ae5ce3fe110b` |
| `model_config.json` | sources, sample rate, segment length, input normalisation | `af642c9ac4e3812449c847ec5bc969b15fa791faa4a5d14f2d2de3b7968db809` |

The app pins a specific commit of this repository and checks each file's SHA-256 before
using it.

## Model

- Architecture: Hybrid Transformer Demucs (the open-source `demucs` 4.1 architecture, MIT),
  22.6M parameters, 44.1 kHz stereo, 6 s segments.
- Weights: trained from random initialisation by Mix Directive. No pretrained third-party
  weights were used.
- Training data: music owned by the Mix Directive author, used with full rights. The model
  does not contain or reproduce those recordings.

## Intended use

Separating music the user has the right to process, inside the Mix Directive app (stem
extraction before mixing and Auto-Mix). Results can contain bleed between stems and
artefacts, especially in the "other" stem.

## License

Mix Directive Stem Splitter Model License v1.0 — see [LICENSE.md](LICENSE.md). All rights
reserved.