HTML5 Video does not work with "Video format or MIME type not supported", tried reinstall and clear cache, didn't work.
Hi, as of two days ago, HTML5 video ceased to work for my Firefox installation. I am unable to view all HTML5 video formats on Firefox browser, even including the ones on the Firefox Start Page. Facebook videos do not work. Only Youtube seems to work, for reasons I do not know. WEBM formats and MP4 formats opened using Firefox do not work as well.
I have tried the following: 1. Reinstalled Firefox with Cache Clearing and AppData Clearing, didn't work. 2. Switched to 64 bit Firefox, didn't work. 3. Disabled all antivirus facilities, didn't work. 4. Tried to use the browser in safe mode, did not work.
Do assist on this, thanks.
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Can you please navigate to the YouTube HTML5 page? This website will tell you which formats your browser supports. Please let us know which formats appear checked.
All six formats should appear with check marks beside them by default, if you have the OpenH264 Video Codec provided by Cisco Systems enabled on your browser. This plugin is automatically downloaded with your Firefox installation and can be found in the plugin manager.
In the meantime, you may want to try troubleshooting Firefox with safe mode to see if there is a setting, addon or hardware acceleration that is causing your issue. For more details on Firefox's safe mode, please refer to these Mozilla support articles:
Hi, as mentioned previously I have already tried safe mode, and have also tried disabling hardware acceleration as well. No dice.
When I checked the Youtube HTML5 page, all 6 checkboxes are ticked. Playing Youtube videos in the provided Youtube HTML5 player works; however the playing of WEBM and MP4 files embedded directly onto the page, using Firefox's inbuilt player, either leaves a "Video format or MIME type not supported" message, or simply refuses to play.
By the way, a quick check using Chrome and Edge browsers does work, so I think this is a Firefox thing, and I really prefer Firefox to the other 2 browsers.
I have tried disabling all addins, no dice as well.
Please assist on this more specifically, thanks!
Perhaps it is a bug in Firefox. Please file a bug report on Bugzilla so that our developers can take a look at the issue.
Note: There have been a few users in the past that have had issues while attempting to play 60fps videos. Is your issue isolated to 60fps videos only?
Try to create an allow or allow for session cookie exception for the YouTube website to see if that helps.