# Third-party components This project is GPL-2.0-or-later. Everything below is somebody else's work, under its own licence, and this file records what it is and how it reaches you. Verbatim licence texts are in [`LICENSES/`](LICENSES/). Nothing here is legal advice. It is a factual inventory so that you, or anyone packaging this, can comply without having to re-derive it. | Component | Licence | GPL-compatible | How it reaches you | |---|---|---|---| | [RNNoise](https://github.com/xiph/rnnoise) | BSD-3-Clause | yes | linked at build time against the system `librnnoise`; **not** redistributed here | | [DeepFilterNet](https://github.com/Rikorose/DeepFilterNet) | MIT **or** Apache-2.0 (dual) | yes (taken under MIT) | `dlopen`ed at runtime from the system `libdf.so`, if installed; **not** redistributed here, and not a build dependency | | [Tabler Icons](https://github.com/tabler/tabler-icons) | MIT | yes | **copied into this repository** under `app/src/icons/`, and compiled into `waveline-mixer` | | [PipeWire](https://pipewire.org/) | MIT | yes | linked at build time against the system `libpipewire-0.3` | | [Qt 6](https://www.qt.io/) | LGPL-3.0-only (open source) | see below | linked at build time against the system Qt | ## RNNoise The noise suppression is RNNoise, by Jean-Marc Valin and the Xiph.Org Foundation. `app/src/engine/noisefilter.cpp` calls it directly rather than going through a LADSPA plugin host. Licence: BSD-3-Clause, the *modified* BSD licence, without the old advertising clause. That clause was the reason 4-clause BSD was incompatible with the GPL; without it, BSD-3-Clause is a permissive licence that adds no restrictions the GPL does not already allow, so BSD-3 code may be combined with GPL code and the combination conveyed under the GPL. The RNNoise portions keep their own notice, which is reproduced in [`LICENSES/RNNoise-BSD-3-Clause.txt`](LICENSES/RNNoise-BSD-3-Clause.txt). Copyright holders, per that file: Jean-Marc Valin; Amazon; Mozilla; Xiph.Org Foundation; Mark Borgerding. **This repository does not contain or redistribute any RNNoise code.** The build links against whatever `librnnoise` the distribution provides (`pkg-config --exists rnnoise`), so BSD-3-Clause clause 2 (reproduce the notice with binary redistributions) is not triggered by cloning this repo. It *is* triggered for anyone shipping a built binary (a distro package, an AppImage, a Flatpak), which is why the notice is kept here ready to be included. The trained model weights are downloaded by upstream's own `autogen.sh` from `media.xiph.org` and are built into `librnnoise`. Upstream ships no separate licence for them; they are treated as part of the project and covered by the same `COPYING`. They are trained on the public datasets listed in upstream's `datasets.txt`. ## DeepFilterNet The optional second noise suppression engine is DeepFilterNet, by Hendrik Schröter. `app/src/engine/denoiser.cpp` drives it through libDF's C API (`df_create`, `df_process_frame`, …). Licence: **dual-licensed, MIT OR Apache-2.0**, at the recipient's option. Upstream's wording is "All code in this repository is dual-licensed under either: MIT License or Apache License, Version 2.0". Both texts are kept here: [`LICENSES/DeepFilterNet-MIT.txt`](LICENSES/DeepFilterNet-MIT.txt) and [`LICENSES/DeepFilterNet-Apache-2.0.txt`](LICENSES/DeepFilterNet-Apache-2.0.txt). Copyright holder, per those files: Hendrik Schröter (2021). ### Which half of the dual licence this project takes, and why it matters **This project takes DeepFilterNet under the MIT option.** That is not a formality; it is the whole reason the combination is clean: * **MIT** is a short permissive licence with no patent clause and no termination clause. It is compatible with GPLv2 *and* GPLv3, so it can be combined with this program however this program is conveyed. * **Apache-2.0** is *not* compatible with GPL-2.0-**only**. Its patent retaliation and indemnification terms count as "further restrictions" under GPLv2 §6, which is precisely what that section forbids. The FSF says so explicitly. It *is* compatible with GPLv3, which added the terms needed to absorb it. Because upstream offers both, the incompatible half can simply be declined. Anyone redistributing this alongside DeepFilterNet should say they are taking it under MIT and ship the MIT notice; there is no obligation to reproduce the Apache text, and it is kept here only because upstream ships it. Note that this project is GPL-2.0-**or-later** for the Qt 6 reason described below, so even the Apache-2.0 option would work by way of GPLv3. Taking MIT avoids having to rely on that. ### Why it is `dlopen`ed rather than linked Three practical reasons, one of which is also a licensing convenience: 1. It ships no pkg-config file, and where it is packaged at all it is packaged under a different name on each distribution. 2. Making it a build dependency would mean nobody could build this project without first installing a Rust toolchain. 3. Nothing here links against it, contains it, or ships it. The engine is listed in the mixer as unavailable when the library is absent, and the mixer falls back to RNNoise. `install.sh` *builds* it from upstream sources by default and drops the result in the user's own `~/.local/lib`, but that is the installer acting on the user's machine at their request. This repository still conveys none of it, and `WAVE3_SKIP_DFN=1` turns that step off. Cloning this repository therefore triggers no notice obligation for DeepFilterNet at all. It is triggered for anyone shipping a bundle that *includes* `libdf.so` (an AppImage or a Flatpak), which is why the notice is kept here ready to be included. ### Model weights The trained weights are the `DeepFilterNet*_onnx.tar.gz` archives in upstream's `models/` directory. Upstream publishes **no separate licence for them**; they are part of that repository and are covered by the same MIT-or-Apache-2.0 choice as the code. This repository does not contain, download or redistribute them. The user installs them, and `denoiser.cpp` looks for one in `~/.local/share/waveline/models/`, the usual system paths, or wherever `WAVE3_DFN_MODEL` points. ### What libdf brings with it libDF runs the model with [tract](https://github.com/sonos/tract) (Sonos), not ONNX Runtime. tract is itself dual MIT/Apache-2.0, as is the rest of the Rust crate graph it pulls in. Since all of it is inside a shared library the user installed through their package manager, none of it is this project's to convey, but it is worth knowing that there is no GPL-incompatible component hiding in there. ## Tabler Icons The interface icons under `app/src/icons/` are from Tabler Icons, © 2020-2026 Paweł Kuna, MIT. Unlike everything else on this page these files **are** redistributed: they are committed to this repository and compiled into the `waveline-mixer` binary through the Qt resource system. MIT requires its copyright and permission notice to accompany all copies and substantial portions, so [`LICENSES/TablerIcons-MIT.txt`](LICENSES/TablerIcons-MIT.txt) must travel with any copy of this repository or of a binary built from it. MIT is GPL-compatible, so shipping them inside a GPL binary is fine as long as the notice is preserved. ## Qt 6: why this project is GPL-2.0-**or-later** Qt 6 is offered under LGPL-3.0-only or GPL-3.0-only (or commercially). Qt 6 dropped the LGPL-2.1 option that Qt 5 had. GPL-2.0-**only** and LGPL-3.0 cannot be combined: LGPLv3 permits a recipient to convey the work under GPLv3, and GPLv2-only forbids adding the terms GPLv3 brings. A GPLv2-only application linking Qt 6 is therefore not distributable. The Qt Company GPL Exception 1.0 does not help here. It covers the *output* of Qt's tools and the combination of Qt applications with plugins, not the licence of a program that links Qt's libraries. The remedy is the ordinary one: this project is **GPL-2.0-or-later**. GPLv2 remains one of the licences it is offered under, exactly as before, and because GPLv3 is also available the combination with LGPLv3 Qt is permitted. Only `wavelined` and `waveline-mixer` link Qt. The `waveline-hw` CLI (Python) and the DKMS kernel module do not. ## The DKMS kernel module `scripts/prepare-src.sh` patches the Linux kernel's own `snd-usb-audio` sources. The resulting module is a derivative of the kernel and is therefore conveyed as **GPL-2.0-only**, whatever this repository's scripts are licensed as. The kernel is GPLv2-only and its licence governs the module. This is not in tension with the paragraph above: the module is a separate work from the Qt programs, built separately, loaded by the kernel, and never linked against Qt.