"But why couldn't Mozilla use an extension that supports H264? Similar to Ubuntu's nonfree packages?"
That might not be an unreasonable approach concerning some other aspect of video on the Web, but has only bad consequences in this particular debate.
As you can see, this debate involves Mozilla and co. versus detractors over the following two non-exclusive decision problems:
Support Theora?
Support h.264?
But it's incredibly important to keep in mind the greater issue here motivating these questions, which is the desire for a baseline video format. As soon as anyone suggests delegating video decoding to the operating system, they're clearly divorcing themselves from this particular debate. Perhaps that kind of delegation is a solution to a problem concerning another aspect of video on the Web, but not this one, because it gains nothing in the pursuit for a baseline video format.
That might not be an unreasonable approach concerning some other aspect of video on the Web, but has only bad consequences in this particular debate.
As you can see, this debate involves Mozilla and co. versus detractors over the following two non-exclusive decision problems:
Support Theora? Support h.264?
But it's incredibly important to keep in mind the greater issue here motivating these questions, which is the desire for a baseline video format. As soon as anyone suggests delegating video decoding to the operating system, they're clearly divorcing themselves from this particular debate. Perhaps that kind of delegation is a solution to a problem concerning another aspect of video on the Web, but not this one, because it gains nothing in the pursuit for a baseline video format.