---
license: mit
library_name: coreml
pipeline_tag: audio-to-audio
tags:
  - coreml
  - core-ml
  - ios
  - macos
  - apple
  - on-device
  - source-separation
  - stem-separation
  - music
  - arxiv:2211.08553
---

# HTDemucs — Core ML

*Audio Source Separation*

Split music into 4 stems: drums, bass, vocals, other. 44.1 kHz stereo, FP32.

<p><img src="https://huggingface.co/mlboydaisuke/HTDemucs-CoreML/resolve/main/media/fe22a231c3.gif" alt="HTDemucs demo"></p>

Core ML conversion of [adefossez/demucs](https://github.com/adefossez/demucs) for on-device inference on iPhone, iPad and Mac. Converted with `coremltools`; the packages are stateless, so all sequencing and buffering lives in your Swift code.

| | |
|---|---|
| Task | audio to audio |
| Upstream | [adefossez/demucs](https://github.com/adefossez/demucs) |
| Packages | 1 |
| Download size | 75 MB |
| Minimum iOS | 17.0 |
| Peak RAM | ~1000 MB |

## Files

| File | Size | Compute units | SHA-256 |
|---|---:|---|---|
| `HTDemucs_SourceSeparation_F32.mlpackage.zip` | 75 MB | `cpuOnly` | `0fbb941e15a5b2fa…` |
| **Total** | **75 MB** | | |

`compute_units` is not a suggestion -- it is the configuration the conversion was verified against. Moving a package to a different compute unit can silently change the numerics (FP16 attention overflow) or crash on the GPU.

## Download

```bash
hf download mlboydaisuke/coreml-zoo --include "demucs/*" --local-dir ./demucs
unzip './demucs/demucs/*.zip' -d ./demucs
```

## Use in Swift

```swift
import CoreML

let config = MLModelConfiguration()
config.computeUnits = .cpuOnly   // as converted — see the table above

// Unzip the .mlpackage, drop it into your Xcode target and Xcode compiles it
// at build time:
let model = try HTDemucs_SourceSeparation_F32(configuration: config)

// ...or compile a downloaded .mlpackage at runtime:
let compiled = try await MLModel.compileModel(at: mlpackageURL)
let model = try MLModel(contentsOf: compiled, configuration: config)
```

## Demo

- **Sample app** — [`sample_apps/DemucsDemo`](https://github.com/john-rocky/CoreML-Models/tree/master/sample_apps/DemucsDemo), a standalone SwiftUI project.
- **Models Zoo** — this model is downloadable and runnable inside the [Models Zoo app](https://apps.apple.com/app/id6762083207) on the App Store, no build required.

## Conversion

- Script: [`convert_htdemucs.py`](https://github.com/john-rocky/CoreML-Models/blob/master/conversion_scripts/convert_htdemucs.py)
- Pitfalls hit during conversion (FP16 overflow, ANE buffer limits, stride handling): [`docs/coreml_conversion_notes.md`](https://github.com/john-rocky/CoreML-Models/blob/master/docs/coreml_conversion_notes.md)
- Model index: [CoreML-Models](https://github.com/john-rocky/CoreML-Models)

## License

The conversion inherits the upstream license: **MIT**.

## Credits

- Upstream authors: [adefossez/demucs](https://github.com/adefossez/demucs), 2021
- Core ML conversion: john-rocky (Daisuke Majima)