Hi hotsnr, I understand that the HTML5 video is giving playback issues. It is possible to right click on the HTML5 player and submit playback issues. Make sure you are also seeing all blue here https://www.youtube.com/html5

I'm not seeing all blue there, only the top half.

Edit:. ok i went to about:config and got 2 others to go blue by enabling media sources.

Edit 2:. apparently doing that makes it impossible to use the html5 player in youtube, it just starts to use the flash one every time.

BTW, in my case what happens is, if i put the video in HD (be it fullscreen or not) i will have flickering or, when i don't have flickering i get a lot of video artifacts. This is ONLY on firefox and only on html5 videos (not just on youtube).

And i'm pretty sure it started on FF33 for me, when you added that openh264 plugin, but disabling it doesn't fix the problem...

Edit 3:. So, no one is gonna try to help us with this?

Disabling Hardware Acceleration seems to stop this for me, so far, but that's pretty bad and not really a solution, I could finally use HA with 0 problems for the first time in over a year, since some update broke it for me and i had all kind of problems, in 32 or something it was all fixed for me, and now i'm gonna have to stop using it again to be able to watch any videos...

I completely hate Chrome but i must say, i have 0 problems watching videos with it, be it html5 or flash, fullscreen or not, on all of those the videos run 10 times smoother, with 0 visual problems and with hardware acceleration on the videos and pages enabled.