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Licensing

Pelorus is licensed under the EUPL-1.2. The files that the patch stack adds to FFmpeg stay under FFmpeg's LGPL-2.1-or-later, and a few vendored files keep their own terms (ADR-0171). Lusoris is the copyright holder of everything Pelorus wrote.

REUSE.toml records the copyright and licence of every file in the repository, following the REUSE specification 3.3. A file's own SPDX-License-Identifier line, where it has one, says the same.

Files Licence Rights holder
Everything not listed below: libpelorus/, tools/, scripts/, docs/, the build files, CI, the tests and scripts under ffmpeg-patches/ EUPL-1.2 (LICENSE) 2026 Lusoris
Sources the patch stack adds to FFmpeg: ffmpeg-patches/files/*.c, files/*.h, files/vulkan/*.comp.glsl, and ffmpeg-patches/test/qsv-roi-regression.c, which is built inside FFmpeg's libavcodec/tests/ LGPL-2.1-or-later (LICENSES/LGPL-2.1-or-later.txt) 2026 Lusoris
Of those, the nine Vulkan filter host files ffmpeg-patches/files/vf_pelorus_*_vulkan.c, which follow FFmpeg's model filters vf_gblur_vulkan.c, vf_nlmeans_vulkan.c and vf_scdet_vulkan.c LGPL-2.1-or-later 2000-2026 the FFmpeg developers, 2026 Lusoris
The patches: ffmpeg-patches/0*.patch and ffmpeg-patches/files/*.patch LGPL-2.1-or-later 2000-2026 the FFmpeg developers, 2026 Lusoris
.claude/skills/superpowers/, vendored from obra/superpowers (its NOTICE.md is Pelorus's, EUPL-1.2) MIT (LICENSE) 2025 Jesse Vincent
tools/figures/third_party/interfig/upstream/, Praetor's vendored interfig MIT 2025 Vectorize AI, Inc.
tools/figures/dist/, the figure player (Praetor's loader with interfig and React) EUPL-1.2 AND MIT (THIRD-PARTY-LICENSES.txt) Lusoris, Vectorize AI, Meta Platforms
.devcontainer/praetor-source.*.b64, the Praetor source the dev container builds EUPL-1.2 AND MIT Lusoris, Vectorize AI, Meta Platforms

LICENSES/ holds the text of each licence named here. The root LICENSE is the EUPL-1.2 text, the same bytes as LICENSES/EUPL-1.2.txt.

Releases up to v0.2.2 were published under BSD-2-Clause-Patent for libpelorus (ADR-0105). Those copies keep those terms; the EUPL-1.2 applies from v0.3.0.

Checking the licence of a file

reuse lint checks that every file has copyright and licence information and that LICENSES/ holds exactly the texts the tree uses. It runs in the reuse-lint pre-commit job, in the REUSE lint CI check (.github/workflows/reuse.yml), and by hand:

python3 -m venv /tmp/reuse && /tmp/reuse/bin/pip install 'reuse>=6,<7'
/tmp/reuse/bin/reuse lint

It ends with Congratulations! Your project is compliant with version 3.3 of the REUSE Specification :-) and exit status 0. To see what applies to one file, read its entry in the SPDX document reuse spdx writes:

/tmp/reuse/bin/reuse spdx | grep -A8 'FileName: ./libpelorus/src/interop.c'

praetorctl audit adds two checks: every REUSE.toml table takes effect (REUSE applies only the last table that matches a file, so the whole-tree default comes first), and the root holds one licence file with the declared licence's text:

[PASS] REUSE.toml annotation order: no path of its 9 annotations is matched whole by the annotations after it.
[PASS] root licence: LICENSE holds the text of LICENSES/EUPL-1.2.txt; no other root file named like a licence.

Using libpelorus in another product

This section repeats what the licence texts say and how the European Commission reads the EUPL. It is not legal advice; for a decision about your product, ask a lawyer.

libpelorus and its public headers (pelorus/interop.h, pelorus.h, deband.h, denoise.h) are EUPL-1.2. There is no dual or commercial licence.

What you do What the EUPL-1.2 asks
Distribute libpelorus or pelorus_qp_report, changed or not, inside your product Keep every copyright notice and the licence notice, and include a copy of the licence (Article 5, "Attribution right"). Provide the source, or name a repository where it is "easily and freely available", for as long as you distribute (Article 5, "Provision of Source Code"). This holds for an unchanged copy too
Link your program against libpelorus, statically or dynamically The licence leaves what counts as a derivative work to the applicable copyright law (Article 1, "Derivative Works"). The Commission reads static and dynamic linking as creating no condition on the other program. There is no case law on it
Change libpelorus and distribute the result Distribute it under the EUPL-1.2, mark it as modified with the date, and provide its source (Article 5). Combined with a work under a licence in the EUPL's appendix (GPL v. 2 and v. 3, LGPL v. 2.1 and v. 3, MPL v. 2 and others), you may distribute the combination under that licence instead ("Compatibility clause")
Run it on a server for others "Distribution or Communication" includes "providing access to its essential functionalities" (Article 1), so the source obligation applies to that service too
Patents The licensor grants use of its patents "to the extent necessary to make use of the rights granted" (Article 2)

vmafx vendors ten libpelorus interop files byte for byte (ADR-0103). Copies vendored from v0.3.0 on are EUPL-1.2, which is also vmafx's licence for its own code.

The FFmpeg boundary

The patch stack turns Pelorus into part of an FFmpeg build. Three kinds of code meet there:

  • FFmpeg's own sources, LGPL-2.1-or-later (some parts GPL when FFmpeg is configured with --enable-gpl), with the shared FFmpeg fix series applied first: patches to FFmpeg's own files, LGPL-2.1-or-later, published by VMAFx/ffmpeg-patches and not part of this repository or its release archive (ADR-0185);
  • the Pelorus files the stack adds to FFmpeg, LGPL-2.1-or-later like the tree they join;
  • libpelorus, EUPL-1.2, which the filters pelorus_analyze_vulkan, pelorus_deband_vulkan, pelorus_denoise_vulkan, pelorus_grain_estimate_vulkan, pelorus_mc_vulkan and pelorus_scenecut link through pkg-config libpelorus and whose pelorus/interop.h they include.

An FFmpeg binary built this way combines EUPL-1.2 and LGPL or GPL code. The EUPL's compatibility clause (Article 5) lets the combination be distributed under LGPL v. 2.1 or GPL v. 2 or v. 3, which its appendix lists; where the obligations conflict, the compatible licence's prevail. Whoever distributes such a binary gives its recipients the corresponding source of all three parts.

Pelorus publishes no FFmpeg binary today: a release carries the patch stack (pelorus-ffmpeg-patches-<tag>.tar.gz) with LICENSES/LGPL-2.1-or-later.txt, LICENSES/EUPL-1.2.txt and a NOTICE that maps paths to licences and names the release commit, the FFmpeg base commit and the shared fix series release the stack needs first (scripts/release/write-patch-notice.sh). A Pelorus-enabled FFmpeg the project publishes later follows vmafx's rule (ADR-0171):

  • configured with --enable-gpl --enable-version3, with x264 and x265 among its libraries; FFmpeg's configure reports the result as "GPL version 3 or later";
  • never configured with --enable-nonfree, so never with the libraries configure lists as nonfree, among them cuda_nvcc, cuda_sdk, libfdk_aac and decklink: such a build is "nonfree and unredistributable" (the Pelorus filters are Vulkan and need none of them);
  • distributed under GPL-3.0-or-later, with a -source image next to it that holds the corresponding source of FFmpeg, its libraries and libpelorus.

The libpelorus part stays EUPL-1.2 on its own; the compatibility clause is what lets it join the GPL-3.0-or-later build.

The tester image (ADR-0173) records the licence of every file it ships in tools/tester/licensing.json; the image build fails on a file, package or licence that record does not cover and writes /usr/share/licenses/pelorus-tester/THIRD_PARTY_NOTICES.txt into the image (ADR-0178, the runbook). The public pelorus-dev image does the same with .devcontainer/base/licensing.json and /usr/share/licenses/pelorus-dev/THIRD_PARTY_NOTICES.txt (ADR-0179, the build guide).

Contributing

A contribution falls under the licence of the file it changes, and a new file under the EUPL-1.2 unless it joins the FFmpeg tree. Every commit carries a Developer Certificate of Origin sign-off; there is no contributor licence agreement (CONTRIBUTING.md).

Sources

Fetched or read on 2026-10-08:

  • EUPL-1.2, the repository copy LICENSES/EUPL-1.2.txt, the European Commission's text: Article 1 (definitions), Article 2 (rights and patents), Article 5 (attribution, copyleft, compatibility and source clauses) and the Appendix of compatible licences.
  • The Commission's EUPL FAQ, https://interoperable-europe.ec.europa.eu/collection/eupl/faqs, on linking: "The EUPL is not viral", and "static and dynamic linking can be implemented with other programs without barriers or conditions".
  • REUSE specification 3.3, https://reuse.software/spec-3.3/; reuse 6.2.0.
  • Praetor docs/guides/licensing-gates.md at the pinned engine 492a00f9.