Right now, Firefox is in a bit of an odd place when it comes to HTML5 video: it supports Ogg Theora and Google's WebM codecs, but not H.264, unlike other major browsers—Internet Explorer, Chrome, and Safari. That's about to change. In a recent blog post, Mozilla Foundation Chair Mitchell Baker writes the following:
Mozilla is on the cusp of changing our policy about our use of video codecs and making use of a format known as “H.264.” We have tried to avoid this for a number of years, as H.264 is encumbered by patents. The state of video on the Web today and in mobile devices in particular is pushing us to change our policy.
Baker points to another blog post, this time by Mozilla CTO Brendan Eich, that details the reasoning behind the change. In a nutshell, Eich says Firefox needs H.264 if it's going to succeed in the mobile space. He also emphasizes that Firefox will remain free and that Mozilla "will not burden [its] downstream source redistributors with royalty fees."
Open standards unencumbered by patents and licensing fees are great, no doubt about it, but I think Mozilla is doing the right thing here. Continuing not to support H.264 would just make things awkward for developers without really benefiting users. Now, hopefully, HTML5 video can begin to overtake Flash around the web.