Séparation de sources

Open-Unmix HQ divise une piste musicale stéréo en quatre stems indépendants — voix, batterie, basse et autres. Quatre modèles BiLSTM indépendants (un par stem) produisent des masques de magnitude sur la STFT du mixage ; un post-filtre Wiener optionnel les concilie. S'exécute sur Apple Silicon via MLX.

Deux moteurs sont disponibles : Open-Unmix HQ (léger, celui par défaut) et HTDemucs (Demucs v4) — un modèle Hybrid Transformer de meilleure qualité, sélectionné avec --engine htdemucs. Les deux s'exécutent sur Apple Silicon via MLX et produisent les mêmes quatre stems à 44.1 kHz.

Présentation

• 4 stems per track — vocals, drums, bass, other. Each is a 2-channel 44.1 kHz stem file.
• Magnitude-mask model — each stem model predicts a non-negative mask applied to the mixture spectrogram; phase is taken from the mixture.
• Wiener post-filter (optional) — soft-mask refinement across all 4 stems so they sum coherently back to the mixture. Adds ~0.5 dB SDR.
• Small footprint — 8.9M params per stem, ~136 MB total for all 4 stems.
• Apache-2.0 — upstream weights under MIT, our CoreML/MLX conversion under Apache-2.0.

Architecture

Four independent stems, each a copy of the same network:

Modèle

HTDemucs (Demucs v4)

For higher separation quality — especially on bass and drums — the package also ships HTDemucs, Meta's Hybrid Transformer Demucs. It merges a spectrogram branch and a waveform branch through a cross-domain transformer; the shipped htdemucs_ft variant is a bag of four fine-tuned sub-models, one per stem. Weights download from HuggingFace on first use. On a directional MUSDB-sample benchmark (museval / BSSEval v4) it averages +3.01 dB SDR over UMX-HQ, with the biggest gains on bass (+5.75 dB).

Démarrage rapide — Swift

import SourceSeparation
import AudioCommon

let separator = try await SourceSeparator.fromPretrained()

let stereo = try AudioFileLoader.loadStereo(
    url: URL(fileURLWithPath: "song.wav"),
    targetSampleRate: 44100
)

let stems = separator.separate(audio: stereo, sampleRate: 44100)
// stems[.vocals], stems[.drums], stems[.bass], stems[.other]
// Each is [[Float]] — left channel, right channel.

try WAVWriter.writeStereo(
    left: stems[.vocals]![0],
    right: stems[.vocals]![1],
    sampleRate: 44100,
    to: URL(fileURLWithPath: "vocals.wav")
)

Pass wiener: true (default) for best quality. Pass targets: [.vocals] to extract only a subset of stems and skip the other models.

CLI

speech separate song.wav                              # all 4 stems into song_stems/ (Open-Unmix)
speech separate song.wav --engine htdemucs            # Demucs v4 — higher quality
speech separate song.wav --engine htdemucs --htdemucs-precision int8  # smaller int8 bundle
speech separate song.wav --stems vocals               # vocals only
speech separate song.wav --stems vocals,drums         # subset
speech separate song.wav --output-dir /tmp/stems/     # custom output dir
speech separate song.wav --verbose                    # show timing

Quand l'utiliser