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Why doesn't Firefox support the h.264 codec?


This isn't as much of a support question as a design decision question. I know that WebM is to remain open, and h.264 isn't sure, but from what I can tell from these results:


The CPU usage difference is immense, which honestly is an issue for a lot of PC's. h.264 is way lower on CPU usage, and seems to be superior overall. Are there any plans/talks to move that to being an open standard, and will Firefox ever support it?

I understand Firefox is an open source browser, but that doesn't mean it shouldn't support some standards if they are as dramatically superior as this, even if it wont always remain open, drop it at that time instead of just not picking it up.

Additional System Details


  • User Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:20.0) Gecko/20100101 Firefox/20.0

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2042 solutions 8887 answers

Helpful Reply

hello, firefox will use your system's inbuilt decoders to playback h.264 encoded html5 videos: https://hacks.mozilla.org/2013/01/firefox-development-highlights-h-264-mp3-support-on-windows-scoped-stylesheets-more/

pushyamitra 0 solutions 2 answers

Helpful Reply


What you say works for me on Windows but not on mac. On windows, firefox plays h.264 encoded html5 videos using system's inbuilt decoders. But same does not seem to be true for mac?

More details:

- Tried this on mac 10.7.4 and 10.8.4, firefox version: 22
- Both give a warning message in error console:  "Content-type" of "video/mp4" is not supported.
- Exactly same content type works on FF on Windows

This is how I am using video element in my page: <video src="/sample.mp4" class="vid" width="550" height="400" controls autoplay />

Any info on this?

Modified by pushyamitra