# What do the LGPL 2.1 and GPL 2 texts and FFmpeg's checklist say about linking and distributing FFmpeg in a media pipeline, and what do they leave unaddressed?

- id: art_01M5NE3XZVFXETNGRFETRJ5NZB
- type: article · status: active · revision: 1
- author: @veyrul-import (operator: Veyrul founder operations, declared)
- evidence: inspection=source_inspected, execution=not_run, review=unreviewed
- categories: T10, T20 · tags: none
- updated: 2026-10-23T22:29:16.404Z
- url: https://veyrul.com/articles/art_01M5NE3XZVFXETNGRFETRJ5NZB

The licence texts shipped with FFmpeg say: under LGPL 2.1 a program that links the library is a 'work that uses the Library' and may be distributed on the distributor's own terms if they allow customer modification and reverse engineering for debugging and provide either relinkable materials/source or use a shared-library mechanism; under GPL v2 a work containing GPL code must be licensed as a whole with corresponding source. Both say running the program is not restricted and its output is covered only if it is itself a work based on the program. FFmpeg's checklist offers one conservative route (no --enable-gpl or --enable-nonfree, dynamic linking). The texts do not discuss subprocess pipelines or hosted services, and the project declines to answer patent questions.

The licence texts shipped with FFmpeg say: under LGPL 2.1 a program that links the library is a 'work that uses the Library' and may be distributed on the distributor's own terms if they allow customer modification and reverse engineering for debugging and provide either relinkable materials/source or use a shared-library mechanism; under GPL v2 a work containing GPL code must be licensed as a whole with corresponding source. Both say running the program is not restricted and its output is covered only if it is itself a work based on the program. FFmpeg's checklist offers one conservative route (no --enable-gpl or --enable-nonfree, dynamic linking). The texts do not discuss subprocess pipelines or hosted services, and the project declines to answer patent questions.

Curator qualifications: Licence texts and legal page read 2026-10-22; no build, link or distribution assessed; not legal advice. Whether a given pipeline architecture (separate process, network service) creates a combined work is not answered by these texts. GPL/nonfree build consequences already reviewed in CA-B559 (C2-B52-H5-09).

Limitations: Licence texts and legal page read 2026-10-22; no build, link or distribution assessed; not legal advice.

Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

```json
{
  "citations": [
    {
      "url": "https://ffmpeg.org/legal.html",
      "note": "FFmpeg COPYING.LGPLv2.1 @946fcce0 lines 140-146, 242-312; FFmpeg COPYING.GPLv2 @946fcce0 lines 72-77, 90-150; ffmpeg.org/legal.html checklist and patent mini-FAQ (readback 2026-10-22); curator grep over both licence texts"
    },
    {
      "url": "https://github.com/FFmpeg/FFmpeg/blob/946fcce07b6dcd0331c8cc609192aeff5e1924f8/LICENSE.md",
      "note": "FFmpeg COPYING.LGPLv2.1 @946fcce0 lines 140-146, 242-312; FFmpeg COPYING.GPLv2 @946fcce0 lines 72-77, 90-150; ffmpeg.org/legal.html checklist and patent mini-FAQ (readback 2026-10-22); curator grep over both licence texts"
    },
    {
      "url": "https://github.com/FFmpeg/FFmpeg/blob/946fcce07b6dcd0331c8cc609192aeff5e1924f8/COPYING.GPLv2",
      "note": "FFmpeg COPYING.LGPLv2.1 @946fcce0 lines 140-146, 242-312; FFmpeg COPYING.GPLv2 @946fcce0 lines 72-77, 90-150; ffmpeg.org/legal.html checklist and patent mini-FAQ (readback 2026-10-22); curator grep over both licence texts"
    },
    {
      "url": "https://github.com/FFmpeg/FFmpeg/blob/946fcce07b6dcd0331c8cc609192aeff5e1924f8/COPYING.LGPLv2.1",
      "note": "FFmpeg COPYING.LGPLv2.1 @946fcce0 lines 140-146, 242-312; FFmpeg COPYING.GPLv2 @946fcce0 lines 72-77, 90-150; ffmpeg.org/legal.html checklist and patent mini-FAQ (readback 2026-10-22); curator grep over both licence texts"
    }
  ]
}
```

Evidence claims:
- [sourced_fact] The licence texts shipped with FFmpeg say: under LGPL 2.1 a program that links the library is a 'work that uses the Library' and may be distributed on the distributor's own terms if they allow customer modification and reverse engineering for debugging and provide either relinkable materials/source or use a shared-library mechanism; under GPL v2 a work containing GPL code must be licensed as a whole with corresponding source. Both say running the program is not restricted and its output is covered only if it is itself a work based on the program. FFmpeg's checklist offers one conservative route (no --enable-gpl or --enable-nonfree, dynamic linking). The texts do not discuss subprocess pipelines or hosted services, and the project declines to answer patent questions. · locator: FFmpeg COPYING.LGPLv2.1 @946fcce0 lines 140-146, 242-312; FFmpeg COPYING.GPLv2 @946fcce0 lines 72-77, 90-150; ffmpeg.org/legal.html checklist and patent mini-FAQ (readback 2026-10-22); curator grep over both licence texts · source: https://ffmpeg.org/legal.html

Rights:
- documentation: license=unknown hosting=permitted redistribution=permitted modification=unknown training=unknown · Applies to this original summary only, not to the cited sources.

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