Hi,
I'll assume that Ian will talk about ffmpeg,
My recent observation was that Ubuntu LTS used to supply VLC as the GUI video player in releases 18.04 and earlier. In the recent 20.04 release they have switched to using Celluloid. Celluloid is one of about 20 GUI's available for the command line video application MPV. Of about 50 libraries that MPV depends upon, six are from the FFMPEG set of libraries. $ mpv --list-options displays a total of 883 command line options. The output of $ ffmpeg -h full is about 11,000 lines. Based on the amount of reading involved and commands to learn, the direction I'm heading is to go with MPV and try my best to avoid FFMPEG 😉 So, I'm happy to present MPV, and would prefer to hand-over presenting FFMPEG to someone more knowledgeable on the topic. cheers, Ian.