Seneste svar på MP4 files won't work in Firefoxhttps://support.mozilla.org/da/questions/13846802022-08-01T04:19:39-07:00That is exactly what it was.
It turns out, that Windows' Media Feature Pack wasn't installing correc2022-08-01T04:19:39-07:00natas.hastingshttps://support.mozilla.org/da/questions/1384680#answer-1524113<p>That is exactly what it was.
</p><p>It turns out, that Windows' Media Feature Pack wasn't installing correctly, despite it's insistence that it was, and the *only* way it will ever install properly is to navigate through Windows 10's aggravating Settings menu and install it specifically via the "add a feature" option under the "optional features" page, which itself is buried behind a few more pages.
</p>It sounds like Firefox is not able to access the "media feature pack" components you installed, but 2022-08-01T01:07:40-07:00jscher2000https://support.mozilla.org/da/questions/1384680#answer-1524047<p>It sounds like Firefox is not able to access the "media feature pack" components you installed, but I don't know what to check for in diagnosing that problem. Hopefully another support volunteer will have a suggestion for that.
</p>I did as you asked, and the issues still persist in the testing profile.
2022-07-31T23:13:55-07:00natas.hastingshttps://support.mozilla.org/da/questions/1384680#answer-1524031<p>I did as you asked, and the issues still persist in the testing profile.
</p>Probably you haven't modified any settings inside Firefox related to playing media, but just to conf2022-07-31T09:04:38-07:00jscher2000https://support.mozilla.org/da/questions/1384680#answer-1523924<p>Probably you haven't modified any settings inside Firefox related to playing media, but just to confirm that it's Firefox and not settings, could you try:
</p><p><strong>New Profile Test</strong>
</p><p>This takes about 3 minutes, plus the time to test a couple problem site(s).
</p><p>Inside Firefox, type or paste <strong>about:profiles</strong> in the address bar and press Enter/Return to load it.
</p><p>Take a quick glance at the page and make a mental note of which Profile has this notation: <strong>This is the profile in use and it cannot be deleted.</strong> That is your current default profile.
</p><p>Click the "Create a New Profile" button, then click Next. Assign a name like Test2022, ignore the option to relocate the profile folder, and click the Finish button.
</p><p>Firefox will switch your default profile to the new one, so click the <strong>Set as Default Profile</strong> button for your regular one to avoid an unwanted surprise at your next startup.
</p><p>Scroll down to Test2022 and click its <strong>Launch profile in new browser</strong> button.
</p><p>Firefox should open a new window that looks like a brand new, uncustomized installation. (Your existing Firefox window(s) should not be affected.) Please ignore any tabs enticing you to connect to a Sync account or to activate extensions found on your system to get a clean test.
</p><p><em>Does MP4 video play in the new profile?</em>
</p><p>When you are done with the experiment, you can close the extra window without affecting your regular Firefox profile. (Test2022 will remain available for future testing.)
</p>