Firefox Support Forum

Whenever I browse the web using Mozilla (Google, Startpage or any other browser) AND Mozilla is set to fullscreen mode I get black bars all around website screen which are not present when Mozilla is set to windowed mode.

I am using: Macbook Air M1 (MacOS Monterey 12.6.6.) and latest Mozilla web browser. I have already tried this solution: "go to about:config in the address bar and try changing the value of full-screen-api.macos-native-full-screen to true" and it did not fix the issue. I am experiencing this for a lot of time now and only on my Macbook which means a specific version of Mozilla cannot be blamed. This happens on ALL websites. Note: I did change about:config quite a lot regarding privacy alterations.

A marquee markdown is not showing in every firefox version I tried (Normal, nightly and dev), none of those versions was showing this markdown. So I'm writing about that. I know it's new, but I think it's very good, and useful markdown.

A recent set of system updates appears to have made most website videos not play in Firefox.

When I inspect the Developer Tools - > Console tab the most detail Firefox gives are an error line similar to: Media resource URL could not be decoded, error: Error Code: NS_ERROR_DOM_MEDIA_METADATA_ERR (0x806e0006)

Internet searches for the error name and error hex do not appear yield any applicable troubleshooting, nor any methods of collecting additional problem data.

How can I obtain more detail on where the error is happening and how Firefox might be interacting with other packages present on my system?

Arch Linux has some older ffmpeg-compat packages, but those don't appear to match any of the web results, in that they're even older versions of ffmpeg.

yay -Ss ffmpeg-compat aur/ffmpeg-compat-55 2.3.6-4 (+24 0.00)

   Compatibility package for ffmpeg to provide versions 55 of libavcodec, libavdevice and libavformat, not anymore provided by the ffmpeg package

aur/ffmpeg-compat-54 1.2.12-4 (+87 0.00)

   Compatibility package for ffmpeg to provide versions 54 of libavcodec, libavdevice and libavformat, not anymore provided by the ffmpeg package

When pausing/starting or moving video feedback volume changes to an fixed volume. Opening video player in youtube default volume is at 41%, I put in at 100% but when I pause it or change to another part of the video, the volume changes to the default again. It's not from OS because with chromium browsers doesn't happen (brave,steam chromium) and with librewolf happens. Wanted to publish a 10 sec video showing the error, because I don't know how to show it with photos.