Firefox v.80.0: some html5 video players are reporting an error

I have also tried refreshing firefox through the about:support page, but that didn't work

Hmm, normally Firefox can play WebM video without external assistance, but there may be problems with MPEG-encoded video if Firefox cannot access the Microsoft Media Foundation components. I have a copy of Google's old test page to see whether the problem with with MP4/H.264:

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

See also: Fix video and audio problems on Firefox for Windows N editions

attached are the results from that page

It seems Firefox is having a problem using Microsoft Media Foundation. Has Firefox mentioned needing to install a Media Feature Pack, as described in the support article I mentioned earlier?

I have not gotten any prompts about it. When I try to follow the steps of that support article my Settings > Apps > Apps and Features > Optional Features > Add a Feature does not have "Media Feature Pack" listed as an optional download.

I don't know why there is a breakdown between Firefox and Windows. I saw a thread like that on Reddit over the weekend, but hopefully you can find a less drastic solution:

https://www.reddit.com/r/firefox/comments/iii3yk/htlm5_not_working_after_update/