Okay I am trying to learn this once and for all.

Let's explain Video File Formats in a very basic way.

I am doing this a) in order to be corrected, b) to help people who have old files that new software won't open. #emca The typical situation I see in EMCA is old video recording files (usually .mov) not opening in X program. SOME .mov files won't always play in certain software, whereas others DO play, which may be confusing. Surely they are the same file type? Sadly, no.