`--enable-nonfree` potentially problematic

[longnguyen2004]

You're not supposed to redistribute binaries with --enable-nonfree. I understand that this is for libfdk_aac, but its license is incompatible with GPL, so they're not allowed to be distributed together.

[seydx]

Thanks for bringing this up!

The FFmpeg binaries in this project are built from my fork of jellyfin-ffmpeg, which includes their patches and build system. Jellyfin intentionally uses fdk-aac-stripped instead of the original fdk-aac - this is a modified version with all patent-encumbered parts removed (HE-AAC, HE-AACv2, xHE-AAC profiles).

Without the patented code, Clause 3 of the FDK AAC license ("NO PATENT LICENSE") becomes a no-op - there's nothing to disclaim when no patents are involved. Fedora Legal has analyzed this and considers fdk-aac-stripped GPL-compatible. Both Fedora and Arch Linux distribute FFmpeg builds with this stripped version.

This was discussed and approved in jellyfin/jellyfin-ffmpeg#61 before being merged. There's also a patch that moves libfdk-aac from the NONFREE list to reflect this.

FFmpeg upstream doesn't officially recognize this interpretation and still treats any fdk-aac as nonfree. But from a practical and legal standpoint, the stripped version without patent-encumbered code is considered safe for redistribution by multiple major Linux distributions.