If I have to pay royalty fees to ship an h.264 decoder, that's not open. If I have to pay royalty fees for my startup to distribute videos in h.264, that's not open.
Standardized doesn't mean "open".
[Edit: I think several people in this thread disagree what Open means. Since this is the context of a Mozilla story, I think it is fair to use "Open" in the sense of "Open Source".]