Mozilla is considering supporting H.264 natively in a future version of Firefox, but there are no plans yet for when this may happen.

See also:

• bug 541286 - MPEG2 and MPEG4/H264 support for HTML5 <video>

(please do not comment in bug reports)

The debate is spread across blogs and newsgroup posts, and you're not likely to get a clear picture from a single bug report. The following article is an interesting read, with links to the sources of the quotes.

• Idealism vs. pragmatism: Mozilla debates supporting H.264 video playback

For the time being, the best you can do is try your luck with Microsoft's add-on.

• Windows Media Player plug-in
• HTML5 extension for WMP plug-in

Should that fail, you can open Internet Explorer in a Firefox tab using the following extension.

• IE Tab Plus

(fixed link - c)

Thank you Gingerbread_Man for this information. But it seems to me IE 9 doesn't support it natively either. I was under the impression natively means no add-on's or some "other" program must be installed also so the browser can call it.Is this an incorrect impression?

I used IE9 (64 bit) as this runs with no add-on's and went to vimeo. I received the same error, so I went with IE9 and again the same error. Could this problem be how vimeo implement HTML5? Is there another site that can be used?

You're welcome.

Yes, Internet Explorer 9 does have built-in support for H.264 videos. On the following page, you should see that IE9 is able to play the first video.

• www.quirksmode.org/html5/tests/video.html

Given that solving issues with IE is outside the scope of Firefox Support, I suggest you ask about the problem on the Vimeo forum:

• vimeo.com/forums/help