Description: When you reload (refresh) a page with HTML 5 video and/or audio elements, the elements are marked with an "X" indicating that they cannot be played, and in fact they cannot be played. This is true at least for Ogg Theora and Ogg Vorbis; I haven't tried with other types of media.

If, instead of an HTML page with video/audio elements, you open the URL of the media file itself, then Firefox will *sometimes* display an error message such as

"File not found

Firefox can't find the file at http://mypage.iu.edu/~gdweber/info/i210-2011/media/test.ogg.";

This does not seem to be coming from the web server, which would give a different (404) error message, so it seems that Firefox is looking for the cached page and not finding it.

Additional info:

* package version(s): 9.0.1-1

* config and/or log files etc.: ?

* details:

1. The problem does not occur with Chromium 16.0.912.63-2 and Opera 11.60-1, so it does not appear to be due to a web server error.

2. The error also occurs when the Firefox binary release (http://releases.mozilla.org/pub/mozilla.org/firefox/releases/9.0.1/linux-x86_64/en-US/firefox-9.0.1.tar.bz2) is used instead of the Arch Linux package, so it does not appear to be an error in the Arch Firefox package per se.

3. But the error does not occur when the Firefox binary release is installed on Ubuntu 11.10, so it does not appear to be an upstream bug in Firefox either.

4. So what could it be? The interaction of Firefox with some version of a library that's peculiar to Arch Linux, but not used by Chromium or Opera?

5. Or maybe it is an upstream Firefox bug peculiar to the x86_64 binary, because the Ubuntu system that I tested on was i686.



Steps to reproduce:

1. Visit a web page containing HTML 5 video and/or audio elements; for example, any of these:

- http://mypage.iu.edu/~gdweber/info/i210-2011/media/test.html
- http://people.xiph.org/~maikmerten/demos/bigbuckbunny-videoonly.html
- http://tinyvid.tv/show/2mdmrqjd1mend

or on the URL of one of the media files referenced from the HTML page, for example,

- http://mypage.iu.edu/~gdweber/info/i210-2011/media/test.ogg
- http://mypage.iu.edu/~gdweber/info/i210-2011/media/test.ogv

2. Click on the "reload current page" tool

3. Observe the video/audio elements have an "X" mark and may be grayed out
(or in the case of media files, an error message as described above).

4. Click on the video/audio element, attempting to play it -- it will not play.