If you are trying to play a video in the Firefox browser but you receive Video format or MIME type is not supported error message on the player, these solutions are likely to help you. This problem occurs when your browser lacks certain functionality that is required to play that video.
Video format or MIME type is not supported
- Install, re-install Adobe Flash Player
1] Install or re-install Adobe Flash Player
Adobe Flash Player is the primary thing you need to play such a video. Although you may be able to play similar videos without installing the Adobe Flash Player, you need to install that if you are getting such an error message. To install it, visit the official adobe.com website.
In case, you already have it installed on your computer; you can try uninstalling and then re-installing it.
To do so, enter this in the address bar and hit the Enter button:
You need to click the I accept the risk button to go further. After that, look for:
If the Value is set to False, just double-click on it to make it True. After that, reload the page and check if you can play the video or not.
Other things you could try is – Disable all the add-ons, clear the web cache, update your browser and see if that helps.