Ffmpeg is a fantastic video and audio converter to edit & create video & audio files. As is typical of *nix command line tools, ffmpeg has several options that need to be correctly configured to be able to use the tool properly to edit videos or audios.
Architecturally, ffmpeg works with streams of video, audio, images or other data files that are passed through various reader/ writer (demuxer/ muxer) and encoder/ decoder layers for the editing and creating video and audio files:
Image Credit: Official Ffmpeg Linux Manual
The command prompt may be a little overwhelming to start off, but a little playing with the tool shows reveals its immense potential. The official documentation page & Linux manual has a few examples to get you started.
Beyond this there are several online resources, blogs and articles such as this, this, this & this, etc. which have listed down the different ffmpeg commands with options. On the other hand, for those averse to the shell prompt, there are several GUI tools written on top of ffmpeg which can be explored.
