Anyone please!!! I've tried Reboot with Addons disabled. No help.

G_Eak,

Would you please make the link to that porn site unclickable ?

You can do so by putting two apostrophies in front and behind the dot, like so :

xvideos''.''com

This is a public forum ......

Did you notice any changes since your problem in  this thread   was solved ?

I saved passwords/favorites, deleted Firefox completely including profile and then reinstalled. I'm now able to do Youtube but not much else. YouTube working gave me a false sense of accomplishment.

Problem in YouTube "sometimes" reappears. https://www.youtube.com/watch?v=A_AzAoL5dR4 CNN - YouTube - How eating at McDonald's will be different because of Covid-19

Your browser does not correctly recognize any of the video formats available. Click here to visit our frequently asked questions about HTML5 video.

First of all :   thank you for making that link unclickable !

I am now going to ask a fellow contributor to take a look at your problem
and see if he knows what's going on.

Sorry about the link and thank you for anything you could do!!!

Hi G_Eak, a few initial questions:

(1) Do your other browsers show the video in a player in a page, or show it in a tab, or offer it as a download?

(2) Can you check the following diagnostic page that queries your Firefox about what kinds of video it can play:

https://www.jeffersonscher.com/sumo/html5-video.html

Normally, it would report supported, probably, probably, supported, supported, supported.

(3) Do you recall changing any preferences in about:config related to media?

(4) Do you use any "downloaders" or "recorders" that may intercept videos coming in to Firefox?

See also:

• https://support.mozilla.org/en-US/kb/fix-video-audio-problems-firefox-windows
• https://support.mozilla.org/en-US/kb/fix-common-audio-and-video-issues
• https://support.mozilla.org/en-US/kb/html5-audio-and-video-firefox

(1) Do your other browsers show the video in a player in a page, or show it in a tab, or offer it as a download?

>> I have an Apple iPad Pro. Videos play in page. >>I think IE is also loaded on this laptop. I'll try it out in a minute.

(2) Can you check the following diagnostic page that queries your Firefox about what kinds of video it can play: https://www.jeffersonscher.com/sumo/html5-video.html Normally, it would report supported, probably, probably, supported, supported, supported.

>> Supported, BLANK, Probably, Supported, Not Supported, Supported >> Yes, that is a blank for MP4/H.264 >> avc1.42001E, mp4a.40.2

>> MSE & H.264 video/mp4; codecs="avc1.4d401e" >> Reports "Not Supported"

(3) Do you recall changing any preferences in about:config related to media? >> I do not think so. (unsure) There should be no changes beyond basic add-ons (adblocker, PDF Viewer). >> I do not know about:config well enough to fool around.

(4) Do you use any "downloaders" or "recorders" that may intercept videos coming in to Firefox? >> Years back I had a downloader. But it was removed at least one year ago.

Could you check here:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

(2) In the search box in the page, type or paste wmf.e and pause while the list is filtered

(3) If the media.wmf.enabled preference has a value of false, double-click it to restore the default value of true

(4) In the search box in the page, type or paste mp4 and pause while the list is filtered

(5) If the media.mediasource.mp4.enabled preference has a value of false, double-click it to restore the default value of true

(6) If the media.mp4.enabled preference has a value of false, double-click it to restore the default value of true

More info on about:config: Configuration Editor for Firefox.

- - - -

If all of those were already true, please check this article and see whether your Windows needs a media feature pack: Fix video and audio problems on Firefox for Windows N editions.

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk. (2) In the search box in the page, type or paste wmf.e and pause while the list is filtered (3) If the media.wmf.enabled preference has a value of false, double-click it to restore the default value of true >> Was already set to "true". No change.

(4) In the search box in the page, type or paste mp4 and pause while the list is filtered (5) If the media.mediasource.mp4.enabled preference has a value of false, double-click it to restore the default value of true >> Was already set to "true". No change.

(6) If the media.mp4.enabled preference has a value of false, double-click it to restore the default value of true >> Was already set to "true". No change.

If all of those were already true, please check this article and see whether your Windows needs a media feature pack: Fix video and audio problems on Firefox for Windows N editions. >>Windows Media Player x86 will load and play. I'll check anyway.

If all of those were already true, please check this article and see whether your Windows needs a media feature pack: Fix video and audio playback problems on Firefox for Windows.

>> Already has Windows Media loaded. OS is not a N or KN version. >> Service Pack 1 already loaded.

(1) Do your other browsers show the video in a player in a page, or show it in a tab, or offer it as a download?

>> I have an Apple iPad Pro. Videos play in page. >>I think IE is also loaded on this laptop. I'll try it out in a minute. >> >> Videos play "IN" IE but not in Firefox.

(2) Can you check the following diagnostic page that queries your Firefox about what kinds of video it can play: https://www.jeffersonscher.com/sumo/html5-video.html Normally, it would report supported, probably, probably, supported, supported, supported.

>> Supported, BLANK, Probably, Supported, Not Supported, Supported >> Yes, that is a blank for MP4/H.264 >> avc1.42001E, mp4a.40.2 >> >> MSE & H.264 video/mp4; codecs="avc1.4d401e" >> Reports "Not Supported" >> >> >> >> Is the "BLANK" or "Not Supported" a problem?

>> >> Is the "BLANK" or "Not Supported" a problem?

Yes. Your Firefox doesn't respond positively to typical queries that sites use to decide whether to try to embed a player for MPEG-encoded media. However, I can't think of any other Firefox setting or external environmental variable that would be relevant to this problem.

Have you ruled out extensions as an issue? You could test in Firefox's Safe Mode. In its Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, any userChrome.css/userContent.css files, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is not running: Hold down the Shift key when starting Firefox. (On Mac, hold down the option/alt key instead of the Shift key.)

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" Help button > Restart with Add-ons Disabled
• (menu bar) Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement?

Yes. Your Firefox doesn't respond positively to typical queries that sites use to decide whether to try to embed a player for MPEG-encoded media. However, I can't think of any other Firefox setting or external environmental variable that would be relevant to this problem.

Have you ruled out extensions as an issue? You could test in Firefox's Safe Mode. In its Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, any userChrome.css/userContent.css files, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is not running: Hold down the Shift key when starting Firefox. (On Mac, hold down the option/alt key instead of the Shift key.)

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" Help button > Restart with Add-ons Disabled
• (menu bar) Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement?

>> I did not remember the small dialog box when using "Restart with Add-ons Disabled so I shut down Firefox and used the "hold down the shift key" method. The small dialog box did come up and I ran in safe mode. >> No change. Firefox will not show video in the browser. A popup window comes up giving me the only option of showing video in Windows Media Player.

I would have to wait until this evening to try but... If I unload Firefox and delete the profile, will that blow away "ALL" add-on/extensions/plugins and load a clean Firefox? Clean about:config.

I know how to reload passwords and favorites

Hi G_Eak, you don't need to delete your current stuff to test in a clean profile:

New Profile Test

This takes about 3 minutes, plus the time to test your problem site(s).

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

Click the "Create a New Profile" button, then click Next. Assign a name like May2020, ignore the option to relocate the profile folder, and click the Finish button.

After creating the profile, scroll down to it and click the Launch profile in new browser button.

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 so we can get a clean test.

Do the problem site(s) work any better in the new profile?

When you are done with the experiment, you can close the extra window without affecting your regular Firefox profile. (May2020 will remain available for future testing.)

Note: if this test changed your default profile, use the Set as Default Profile button for your regular profile to set it back to normal.

Do the problem site(s) work any better in the new profile?

>> No change.  Still pops up window to open videos in Windows Media Player.  Will not play in browser.

I don't know why Firefox on your system doesn't seem to detect the Windows Media Foundation components needed to play MPEG-encoded video. Do you recall the last time it worked normally?