Your system details shows you are using version 74. Is that correct? You said you updated to v77.
See if any of these links help you:

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

https://support.mozilla.org/en-US/kb/troubleshoot-issues-with-plugins-fix-problems

https://support.mozilla.org/en-US/kb/warning-unresponsive-plugin

on 74 at the moment, as it was the last version that played videos successfully, so after installing the 77, talking to people on reddit and uploading the log and nobody knew what else to try I have tried rolling back to the last known good one. unfortunately , no change.

Also, unfortunately, no, tried all the things in those linked pages, no good

If you have Windows 10 N or KN then you may not have the Media Feature Pack installed.
https://support.mozilla.org/en-US/kb/fix-video-audio-problems-firefox-windows

i have windows 7 ultimate x64 the N/KN links arent compatible with my system.

Just for more clarity, chrome has been able to play every single video that firefox cannot. Between it working and not, not a single thing was changed.

            No updates or changes to my firewall
            No updates or changes to my anti virus
            No updates or changes to my add ons.
            No updates or changes made to my system/os

Whatever is going in , it's above my head

Update: I have updated my browser back to 77.0.1

and I also tried installing nightly. Same issue persists.

I am sorry that I cannot give you much to go on, all i can tell you unequivocally is that starting yesterday morning, with not a single change made to my system all versions and builds of firefox became unable to load a single video on any website, but other browsers have no such issue and no currently existing suggestions or "fixes" have been able to solve this issue

Please try the Beta version
https://www.mozilla.org/en-US/firefox/channel/desktop/

No good.

I have tried running mozregression, selected 74 as last known good build and 77 as problem. every single version mozregression downloaded = same issue nightly variations= same issue beta version = same issue.

other browsers, remain working, but no iteration of firefox works on my system for some reason

I have now taken extreme measures and completely reinstalled my os. Fresh install of windows, still using windows 7 Fresh install of 77.0.1 no videos work Fresh install of nightly no videos work Fresh install of beta version no videos work. No add ons were installed, I disabled the firefox enhanced tracking protection, disabled hardware acceleration, still, nada

Fresh install of chrome and everything works fine, if chrome wasnt so needlessly demanding on resoures I would just not bother with firefox, this is ridiculous

Hello RedHood,

FredMcD   asked me to tell you that due to certain circumstances, he can't post anything on the support forum right now.