Just some stuff about me.
FFMPEG has hundreds of different codecs to edit, convert to and play from. In your journey to mastering FFMPEG you’ll face the word ‘codec’ so often that not understanding what one is, is a disservice to yourself.
Wikipedia explains a codec as:
This book focuses on the mp3 codec for audio and H.264 (x264) codec for video. Due to their popularity and ease of use with modern software there’s rarely a disadvantage to using these codecs. For example, it’s much easier to post a mp4 file with mpeg4 codec to Instagram than it is to upload an Apple mov video.
Codecs are not the container that makes up an mp4 but the encoded data to allow mp4 files to be understood by a computer.