Description: Firefox does not play the sound on some Ogg Theora ( + Vorbis) videos.

Additional info:

* package version(s): Firefox 9.0.1-1

* config and/or log files etc.:

* Other details:

- Actually, Firefox does play sound for most Ogg Theora video I could find on the web,
but not for those I have recorded with recordmydesktop.

- Chromium 16.0.912.63-2 and Opera 11.60-1 both play the sound track.

- Not only in the Arch firefox package, but also in the binary downloaded from http://releases.mozilla.org/pub/mozilla.org/firefox/releases/9.0.1/linux-x86_64/en-US/firefox-9.0.1.tar.bz2 also fails to play the audio track.

- On Windows and Macintosh, Firefox 9.0.1 plays the audio track.

- On Ubuntu 11.10, Firefox 9.0.1 (not the Ubuntu package, which is
Firefox 8, but downloaded from http://releases.mozilla.org/pub/mozilla.org/firefox/releases/9.0.1/) plays the audio track.

- So, it doesn't seem to be the Arch Linux Firefox package per se that is to blame, since the upstream Firefox also fails to play the sound track on Arch Linux; but neither does it seem to be an upstream bug, since the upstream Firefox, when installed on Ubuntu, plays the sound track. My guess is that it may be the combination of Firefox with some library version peculiar to Arch Linux -- but a library not used by Chromium or Opera?

Steps to reproduce:

1. With Firefox, open the URL http://mypage.iu.edu/~gdweber/info/i210-2011/media/test.html
2. Turn speakers on.
3. Play the HTML5 video (not the audio on the same page).
4. Observe there is no sound.