Tahoma ships with FFmpeg, and uses FFmpeg through command line commands.
Tahoma does not directly use FFmpeg libraries or code.

As of July 2020, Tahoma is shipping with FFmpeg 4.3 LGPL version from https://ffmpeg.zeranoe.com/builds/

FFmpeg source code can be found at:
https://github.com/turtletooth/FFmpeg
or 
https://github.com/FFmpeg/FFmpeg