FFmpeg's C API has pretty good documentation: https://www.ffmpeg.org/doxygen/4.0/

The C API documentation includes a ton of example code: https://ffmpeg.org/doxygen/4.0/dir_687bdf86e8e626c2168c3a2d1...

In addition to having both a man page and a --help option, The FFmpeg CLI tool has very thorough documentation: https://ffmpeg.org/ffmpeg.html

I don't understand how FFmpeg could in any way be considered to have no documentation and no code samples.