Browser video engine - unmodified upstream distribution

@ffmpeg/ffmpeg 0.12.15, MIT, Copyright 2019 Jerome Wu
https://www.npmjs.com/package/@ffmpeg/ffmpeg/v/0.12.15
https://github.com/ffmpegwasm/ffmpeg.wasm
https://github.com/ffmpegwasm/ffmpeg.wasm/tree/main/packages/ffmpeg

@ffmpeg/core 0.12.10, GPL-2.0-or-later
https://www.npmjs.com/package/@ffmpeg/core/v/0.12.10
Build source and dependency recipes for the core release:
https://github.com/ffmpegwasm/ffmpeg.wasm/tree/71aa99d37c02a7b4c435275ca9ef50e612f6efa1
https://github.com/ffmpegwasm/ffmpeg.wasm/commit/71aa99d37c02a7b4c435275ca9ef50e612f6efa1
https://github.com/ffmpegwasm/ffmpeg.wasm/tree/71aa99d37c02a7b4c435275ca9ef50e612f6efa1/build
https://github.com/ffmpegwasm/ffmpeg.wasm/blob/71aa99d37c02a7b4c435275ca9ef50e612f6efa1/Dockerfile
FFmpeg upstream: https://ffmpeg.org/download.html
libvpx upstream: https://chromium.googlesource.com/webm/libvpx/

The core binary includes third-party FFmpeg dependencies as configured by
the upstream build. No changes were made to the distributed core binaries.
Keep license notices and corresponding-source access when redistributing.