I don't know a huge amount about video encoding, but I presume this is one of those libraries outlined in xkcd 2347[0]?
[0] - https://xkcd.com/2347/
replies(5):
[0] - https://xkcd.com/2347/
[0] https://link.springer.com/article/10.1007/s11214-020-00765-9
Linux doesn't really have a system codec API though so any Linux video software you see (ex. VLC, Handbrake) is almost certainly using ffmpeg under the hood (or its foundation, libavcodec).