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.

Yet the same browser does this on my test server.

Any thoughts on how to deal with this?