So I have read a lot about the subject, and thought that the following code would work with all up to date browsers:
<video width="640" height="480" controls="controls">
<source src="video/filename.mp4" type="video/mp4" />
<source src="video/filename.webm" type="video/webm" />
Your browser does not support the video tag.
The mp4 file is coded in H.264.
I have a LAMP server at home and this works with my Linux client computer with Firefox, Chromium and Epiphany.
However when I load to my Web host, it fails with Firefox. On the same client I use for testing with my home server. I get an Firefox error saying "No video with supported format and MIME type found"
If I remove the mp4 line, Firefox is happy to render the webm file.
So when I access my web server, the Firefox client is dying at the mp4 file and not skipping it to use the webm file.
I would suspect it is too late by the time you've suggested it in the browser and since according to #1 it seems to work locally but not when externally live? Those are the only two differences so adding the correct MIME on the server might work. This is presuming it isn't a plugin bug, which again will be MIME or codec related albeit I thought there were issues anyway regarding that codec and you might need to be more specific in the markup attributes.
And while the Apache server is what is defferent in the two cases, I don't see why that would make a difference. The MIME type is specified in the source tag itself.
It makes a difference. The server also specifies the MIME type in the Content-Type header. Firefox respects it -- if it says, say, text/plain for both videos, Firefox will fail to load both of them. (Opera used to do this as well.)