Fixing the desktop recording issues is beyond my scope.
However, Firefox is able to play many YouTube videos, so it seems to be
an issue regarding to a used codec or similar.
There's no need to avoid YouTube, you "only" need to convert your camera
recordings in a way, that the videos can be played with HTML 5 capable
browsers.
I don't know how much work the "only" to do would cause, since I have
given up Linux video a long, long time ago. I already have more than
enough issues with Linux audio, still couldn't get the RME card working
as it should work ;).