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StemStudio

Open Source Licences

Last updated: August 7, 2026

This Service is built on the open-source software and pretrained models listed below. Copyright in each remains with its respective holders, and the Service uses each under the terms of its licence.

The AI model files are downloaded to your browser directly from the sources linked below, not served from this site.

AI models

Demucs (Hybrid Transformer Demucs)
Separation for the Standard, 4-stem, 6-stem and Ultra presets
Copyright (c) Meta Platforms, Inc. and affiliates.
MIT
To run in a browser the Service uses a published ONNX conversion of the released weights (export and parity checks by StemSplit, stated as MIT). The weights were trained on MUSDB18-HQ and further music data.
facebookresearch/demucsONNX conversion
Spleeter
The Fast 2-stem preset, and the 4-stem split on lighter devices
Copyright (c) 2019-present Deezer SA
MIT
Also used via published ONNX conversions: the 2-stem nets derive from sherpa-onnx (k2-fsa, Apache-2.0), and the 4-stem nets are published under Apache-2.0.
deezer/spleeterONNX conversion (4 stems)

Libraries

ONNX Runtime Web
Running the AI models (WebGPU / WebAssembly)
Copyright (c) Microsoft Corporation. All rights reserved.
MIT
microsoft/onnxruntime
React / React DOM
Rendering the interface
Copyright (c) Facebook, Inc. and its affiliates.
MIT
facebook/react
FFmpeg / ffmpeg.wasm
Bundled in the shipped code; currently disabled and not used for conversion
Copyright (c) the FFmpeg developers / Copyright (c) 2019 Jerome Wu
FFmpeg: LGPL-2.1-or-later; @ffmpeg/ffmpeg: MIT
The GPL-enabled core is not used. Licence texts and corresponding source are available from the sources above.
FFmpeg licensingffmpegwasm/ffmpeg.wasm
LAME / lamejs
Writing MP3 files
Copyright (c) the LAME project / lamejs contributors
LGPL-3.0
This Service uses LAME (lamejs) for MP3 encoding. It is loaded as a separate, unmodified library, and its source is available from the sources above.
LAME (lame.sourceforge.net)@breezystack/lamejs
JSZip
Building the ZIP when you download all stems at once
Copyright (c) 2009-2016 Stuart Knightley, David Duponchel, Franz Buchinger, António Afonso
Dual-licensed MIT or GPL-3.0-or-later (the Service uses it under MIT)
Stuk/jszip
heic2any
Converting HEIC images
Copyright (c) 2020 Alex Corvi
MIT
alexcorvi/heic2any
pdf-lib
Merging PDFs (Kit)
Copyright (c) 2019 Andrew Dillon
MIT
Hopding/pdf-lib
PDF.js
Drawing PDF pages so they can be picked (Kit)
Copyright Mozilla Foundation
Apache-2.0
mozilla/pdf.js
Radix UI Primitives
Accessible behaviour behind checkboxes, tabs, dialogs and the like
Copyright (c) 2022 WorkOS
MIT
radix-ui/primitives
Lucide
The interface icons
Copyright (c) 2026 Lucide Icons and Contributors
ISC
Derived from Feather Icons (Copyright (c) 2013-2023 Cole Bemis, MIT).
lucide-icons/lucide
MP4Box.js
Reading the structure of video files
Copyright (c) 2012. Telecom ParisTech/TSI/MM/GPAC Cyril Concolato
BSD-3-Clause
gpac/mp4box.js
mp4-muxer
Writing MP4 output
Copyright (c) 2023 Vanilagy
MIT
Vanilagy/mp4-muxer
@vercel/analytics
Page-view counting
Copyright (c) Vercel, Inc.
MIT
vercel/analytics
@vercel/speed-insights
Core Web Vitals measurement
Copyright (c) Vercel, Inc.
Apache-2.0
vercel/speed-insights
clsx
Building class names (used across the interface)
Copyright (c) Luke Edwards
MIT
lukeed/clsx
tailwind-merge
Collapsing conflicting Tailwind classes
Copyright (c) 2021 Dany Castillo
MIT
dcastil/tailwind-merge
class-variance-authority
Variant styling for buttons and similar controls
Copyright (c) 2022 Joe Bell
Apache-2.0
joe-bell/cva
node-qrcode
Generating QR codes (Kit)
Copyright (c) 2012 Ryan Day
MIT
Uses dijkstrajs internally (Copyright (c) 2013 Tim Robinson, MIT).
soldair/node-qrcode

MIT License (common text for everything marked MIT above)

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Other licence texts

The full text of Apache-2.0, LGPL-2.1 and LGPL-3.0 is available here.

Apache License 2.0GNU LGPL v2.1GNU LGPL v3.0

Trademarks and affiliation

Product and organisation names shown here are trademarks or registered trademarks of their respective owners. This Service is not endorsed by, sponsored by, or affiliated with any of these projects or rights holders; it uses publicly released software under the applicable licences, on an "as is" basis. None of the rights holders warrants anything about this Service.

About the audio you use

This Service is intended for audio you own the rights to, audio you have permission to use, or use within the scope of private use. Please do not use it on material obtained by circumventing copy protection on a streaming service, or otherwise copied without the rights holder’s permission.

If anything here is wrong or missing, please tell us.

Email: contact@stemstudio.jp