Slowly but surely, Firefox is starting to support the patent-encumbered H.264 and MP3 codecs for its implementation of HTML5 video and audio.
The big battle over video codecs is long gone. Mozilla lost and eventually made the decision to support these codecs alongside the royalty-free ones like WebM or OGG.
But Firefox won't support the codecs outright; rather, it will rely on them being supported at the operating system level.
Firefox has had support for them for a while, but it is now enabled by default and working out of the box. Work is still in progress for Linux and Mac OS support.
WebRTC is also finally enabled by default in Firefox Nightly, it too has been working for a few months now but Mozilla is only now confident enough in its implementation to leave it on.