FFmpeg.wasm wrapper: MIT, see LICENSE.ffmpeg.
@ffmpeg/core 0.12.10: GPL-2.0-or-later, see COPYING.GPLv2.
Core source and reproducible build scripts: https://github.com/ffmpegwasm/ffmpeg.wasm/tree/core%40v0.12.10
FFmpeg upstream: https://ffmpeg.org/
The core is distributed unmodified.