There was a time when it was very frustrating trying to get video (and occasionally audio) to playback on a lot of different platforms. I frequently found that a film would play on one computer but not on another. The trouble was that not all machines had the different ‘codecs’ to play the film.
Fortunately the situation has improved though it still isn’t perfect.
I don’t have the answer (unfortunately) but I do have some notes to explain a bit more about what is going on. If anyone has any articles or weblinks that expand the topic further then please add a comment.
I hope the notes help.