ok, got it why there isn't any H.264 support....I should have figured out by myself.
Another issue: http://www.disqus.com doesn't load styling properly but most importantly, the Disqus comment's widget always fails to load in any site I tried. It's something I recall already happening many months ago but looks like the bug is still here.
It loads only the link "Powered by Disqus.com"
thanks