---
license: other
license_name: mixed-see-below
tags:
- music-source-separation
- music-transcription
- beat-tracking
- music-mood
- onnx
- onnxruntime-web
---

# Sound Space – browser models

ONNX files used by the **Sound Space** web app to analyse music entirely inside the user's browser
(onnxruntime-web, WebGPU). Audio never leaves the user's device; only these model files are downloaded.

Large weights are stored as float16 and cast back to float32 at load time (`Cast` nodes), so computation is float32.

| File | What | Original project | License |
|---|---|---|---|
| `htdemucs_6s.onnx` | Demucs v4 6-stem separation core, STFT/iSTFT moved outside the graph (sevagh/demucs.onnx method) | facebookresearch/demucs (htdemucs_6s) | MIT, Copyright (c) Meta Platforms, Inc. and affiliates |
| `htdemucs_6s_mobile.onnx` | Same htdemucs_6s weights exported with a 2.93 s segment (129024 samples) for phones: CPU (WebAssembly) peak memory during a run drops from about +1.7 GB to about +190 MB | facebookresearch/demucs (htdemucs_6s) | MIT, Copyright (c) Meta Platforms, Inc. and affiliates |
| `basic_pitch_nmp.onnx` | Basic Pitch note/onset model (unchanged) | spotify/basic-pitch | Apache-2.0, Copyright Spotify AB |
| `beat_this_final0.onnx`, `beat_this_melfb.f32` | Beat This! beat/downbeat tracker (final0) and its mel filterbank | CPJKU/beat_this | MIT (code and published weights) |
| `drumsep.onnx` | Drum stem split into kick / snare / cymbals / toms (HDemucs), STFT outside the graph | inagoy/drumsep | Repository MIT. The weights are distributed by the author via Google Drive without a separate license statement. |
| `clap_audio.onnx` | CLAP audio encoder + projection (input: log-mel [1,1,1001,64] at 48 kHz, output: L2-normalised 512-d embedding). Mood text embeddings are precomputed in the app | laion/clap-htsat-unfused (Hugging Face) | Apache-2.0 |
| `onset_mel_44k.f32` | librosa mel filterbank (44.1 kHz, n_fft 2048, 128 bands) | librosa | ISC |

Conversion scripts and verification (ONNX vs PyTorch differences, evaluation results) are in the Sound Space project
(`scripts/export_demucs_onnx.sh`, `scripts/export_beat_this_onnx.py`, `scripts/export_drumsep_onnx.py`, `scripts/export_clap_onnx.py`, `scripts/onnx_fp16_weights.py`).