Open-Source Licences

Last updated: 14 September 2026

AudioKit runs its tools directly in your browser thanks to third-party open-source software, served from our own domain. This page lists those components, their licences, and where to obtain their source code. We are grateful to their authors and maintainers.

FFmpeg (ffmpeg.wasm)

AudioKit distributes a WebAssembly build of FFmpeg: the package @ffmpeg/core, version 0.12.6, from the ffmpeg.wasm project. It powers the audio processing of our free tools, and the H.264 video export of four video tools.

This binary includes the x264 and x265 libraries and is therefore licensed, as a whole, under the GNU General Public License, version 2.0 or later (GPL-2.0-or-later). FFmpeg is a trademark of Fabrice Bellard, originator of the FFmpeg project. The accompanying JavaScript wrappers (@ffmpeg/ffmpeg, @ffmpeg/util) are licensed under MIT.

--target-os=none --arch=x86_32 --enable-cross-compile --disable-asm --disable-stripping --disable-programs --disable-doc --disable-debug --disable-runtime-cpudetect --disable-autodetect --nm=emnm --ar=emar --ranlib=emranlib --cc=emcc --cxx=em++ --objcc=emcc --dep-cc=emcc --extra-cflags='-I/opt/include -O3 -msimd128' --extra-cxxflags='-I/opt/include -O3 -msimd128' --disable-pthreads --disable-w32threads --disable-os2threads --enable-gpl --enable-libx264 --enable-libx265 --enable-libvpx --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libopus --enable-zlib --enable-libwebp --enable-libfreetype --enable-libfribidi --enable-libass --enable-libzimg

Corresponding source code — all versions below are the ones pinned by the Dockerfile at the exact build commit of the distributed binary:

• Build scripts and toolchain: ffmpegwasm/ffmpeg.wasm @ e0d4c62
• Package as distributed: @ffmpeg/core 0.12.6 (npm tarball)
• FFmpeg sources, tag n5.1.4: github.com/FFmpeg/FFmpeg @ n5.1.4
• x264 sources, ffmpegwasm fork, branch 4-cores: github.com/ffmpegwasm/x264 @ 4-cores
• x265 sources, ffmpegwasm fork, branch 3.4: github.com/ffmpegwasm/x265 @ 3.4

If you would like the complete corresponding source delivered another way, write to hello@audiokit.net. This written offer is valid for at least three years from the date the binary was distributed to you, and the copy will be provided for a charge no greater than our cost of physically performing the distribution — in practice, free of charge by electronic means.

Other components

• wavesurfer.js — BSD-3-Clause — source · licence text
• mp4box.js (GPAC / Telecom ParisTech) — BSD-3-Clause — source · licence text
• mp4-muxer — MIT — source · licence text
• fflate — MIT — source · licence text
• uPlot — MIT — source · licence text
• browser-id3-writer — MIT — source · licence text
• jsmediatags — BSD-3-Clause — source · licence text
• FingerprintJS (open-source edition) — MIT — source — loaded from the official openfpcdn.io CDN, not redistributed by this site

The Web Audio API, WebCodecs and other browser features used by AudioKit are web standards implemented by your browser and are not third-party software distributed by this site.