Firefox reports "No Video with Supported Format and Mime Type Found"

Question

This code worked fine for mp4 video, but it did not work for .3gp, .avi and .flv files.

<video width="320" height="240" controls>
  <source src="<s:url action='downappsuservideo'> 
                   <s:param name="id" value="#session['id']"/>
               </s:url>" >
  Your browser does not support the video tag.
</video>

Solution

You need to check for the limitations that Firefox (as any other browser) may have when working with HTML5.
The HTML5 universe is constantly evolving, and the missing support of some functionality, codec, etc. will eventually be introduced soon or later in the future.

Meanwhile, check what Firefox is capable of in the following page:

HTML5 TEST

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At the time of writing, it scores an overall 465 out of 555, of which 29 out of 33 on video playback.

Specifically, the CODEC situation is the following:

MPEG-4 ASP support    : No  ✘    
H.264 support         : Yes ✔
H.265 support         : No  ✘
Ogg Theora support    : Yes ✔
WebM with VP8 support : Yes ✔
WebM with VP9 support : Yes ✔

Then

• give the user the link to download the video when unreproducible, or
• use another player as a fallback, or
• convert your videos, or
• whatever.

Also read Mozilla’s article on supported media formats.