I need a sanity check- as I understand it, Firefox now supports mp4 video, so only one type of video file is needed by html5 players, ie no more:
src="movie.mp4" type="video/mp4" src="movie.ogg" type="video/ogg"
Just src="movie.mp4" type="video/mp4"
(I am going to use videojs).
I checked also on http://caniuse.com/#feat=mpeg4html5videomp4video.js
Unfortunately, I don't think it is this simple - this link from Mozilla gives the best up to date picture in my experience, but as you are aware things change constantly so it is worth checking several sources:
You also need to be aware of some subtleties even when mp4 is supported:
Some links for CENC and DASH: