The transcode utility is listed as being used for xvid, lame, ac3.
However, it is quite difficult to acquire this utility.
The homepage https://transcoding.org/
is a spam blog.
The repository https://bitbucket.org/france/transcode-tcforge/
is gone.
The only mirror of its source code is provided by LFS: https://anduin.linuxfromscratch.org/BLFS/transcode/transcode-1.1.7.tar.bz2
(and cache.nixos.org
, indirectly)
I think it would be best to replace its usage with ffmpeg, which would also give us a lot more options for audio formats.