Licenses & transparency
Everything this site does, everything it runs in your browser, and where all of it comes from.
What happens to your files
- Your files are read and converted inside your browser. They are never uploaded anywhere.
- Nothing is stored: no account, no history. Closing the tab forgets everything.
- No ads, no analytics, no trackers, no cookies.
- The only network requests are the files of this site itself. The first time you convert something, the browser downloads the conversion engine (about 31 MB) from this same site.
- Fonts are served by this site, not by Google.
The conversion engine
Conversions are done by FFmpeg, compiled to WebAssembly by the ffmpeg.wasm project. This site is not affiliated with either project. FFmpeg is a trademark of Fabrice Bellard.
The engine (ffmpeg-core.wasm and ffmpeg-core.js) is distributed unmodified, under the GNU General Public License, version 2 or later. You are free to use, study, share and modify it under that license.
Its complete corresponding source code is the ffmpeg.wasm repository at tag v12.15. The Dockerfile there pins the exact version of every library below and the build options used.
Inside the engine
| Component | Used for | License |
|---|---|---|
| FFmpegn5.1.4 | Decoding, encoding, filters | GPL-2.0-or-later (built with --enable-gpl) |
| x264ffmpegwasm fork, branch 4-cores | H.264 encoder | GPL-2.0-or-later |
| x2653.4 | H.265 / HEVC encoder | GPL-2.0-or-later |
| libvpx1.13.1 | VP8 / VP9 | BSD-3-Clause |
| LAMEffmpegwasm fork, branch master | MP3 encoder | LGPL-2.0-or-later |
| libogg1.3.4 | Ogg container | BSD-3-Clause |
| libvorbis1.3.3 | Vorbis audio | BSD-3-Clause |
| libtheora1.1.1 | Theora video | BSD-3-Clause |
| Opus1.3.1 | Opus audio | BSD-3-Clause |
| libwebp1.3.2 | WebP images | BSD-3-Clause |
| zlib1.2.11 | Compression (PNG…) | Zlib |
| zimg3.0.5 | Scaling, color conversion | WTFPL |
| FreeType2.10.4 | Font rendering (subtitles) | FreeType License or GPL-2.0 |
| HarfBuzz5.2.0 | Text shaping (subtitles) | MIT (Old MIT) |
| FriBidi1.0.9 | Bidirectional text (subtitles) | LGPL-2.1-or-later |
| libass0.15.0 | Subtitle rendering | ISC |
| Emscripten3.1.40 | Compiler runtime in ffmpeg-core.js | MIT or UIUC (NCSA) |
The rest of the site
| Component | Used for | License |
|---|---|---|
| @ffmpeg/core0.12.10 | The engine above, packaged | GPL-2.0-or-later |
| @ffmpeg/ffmpeg0.12.15 | JavaScript wrapper around the engine | MIT |
| Next.js16.4.0 | Site framework | MIT |
| React19.3.0 | User interface | MIT |
| Tailwind CSS4 | Styles | MIT |
| Geist & Geist Mono | Fonts, served from this site | SIL Open Font License 1.1 |
Patents
Licenses cover the code, not patents. Some formats are covered by patents in some countries: H.264 (AVC), H.265 (HEVC) and AAC in particular. MP3 patents have expired. VP8, VP9, Opus, Vorbis, FLAC, Theora and WebP are royalty-free. Depending on where you live and what you do with the result, using a patented format may require a license from its patent holders.