I've been converting some of my wedding videos to the newer HTML5 <video> tags methodology. To satisfy a reasonable number of case, I supply MP4, WEBM, and OGG sour… (read more)
Other important findings:
1) This problem is limited to the XP (pro-SR3) version of FF, and was shown to recur on 3 different XP machines. I've tested with all versions from 31 through the latest (34 as of this writing). The problem does not happen with Win-7, nor on Chrome on either machine.
2) I have taken the obvious steps of ensuring my .htacess file serves the correct mime types. Note however that the problem is identical (though without the page load time) when I point my browser(s) at a working copy of page on my local (XP) machine, so this should not have anything to do with a server side problem.
3) All video files were prepared using a current version of ffmpeg, and tested with VLC. The page was also tested with Chrome on the same machine with no issues, and friends with MACs and android devices have reported no issues.