Ubuntu – How to get HTML5 h.264 Video working on Firefox

Many of the features on that table are extremely new. The Media Source Extension spec, for example, is still a draft and is still being written. And it's being driven by Google and Netflix. It's going to take time for the spec to mature to a point where Mozilla want to spend any time implementing it.

h.264 support is somewhat easier (if you're on 12.04 - it's currently muddier if you're on 14.04):

sudo apt-get install ubuntu-restricted-extras

Update: In Firefox 30 (should be the default in all supported versions now), the feature is there but it's disabled by default. This should change in Firefox 31 but you can enable MSE by going to about:config (stick that in the address bar) and searching for mediasource. That should leave you with the media.mediasource.enabled option. Double click to enable.

On the Youtube panel the MSE & H.264 option is still crossed out... But the other two MSE options are now green.

you could try this which worked for me:

in firefox enter the about:config page.

find the entries specified below and set them as I've set them below whichs did the trick for me:

media.mediasource.whitelist = false and media.mediasource.webm.enabled = true

Regards, Troels