Firefox Community Forum

Issue Description: I’m experiencing a problem with fullscreen mode while using YouTube on Firefox on Windows 11 with a dual-monitor setup. When I enter fullscreen, the video does not cover the entire screen. Instead, I can still see parts of the Windows desktop or background around the edges of the display.

This issue only happens on Firefox and only when using fullscreen mode on one of my monitors. I have already checked my display settings, scaling, alignment, and hardware acceleration, but the problem persists.

System Details:

Windows 11

Dual-monitor setup

Browser: Firefox (latest version)

Issue: Fullscreen video shows borders and does not fully cover the screen

Expected Behavior: The fullscreen video should completely fill the selected monitor without showing any part of the Windows desktop.

Please advise on how to resolve this issue.

i cant play sound from firefox ive tried restarting my computer, disabling my adblocker, everything i can think of its not my headphones, they work fine with files on my computer im having the same problem with davinci resolve too please someone help i dont know what to do anymore

Whenever I play videos on YouTube in Firefox, the video is always choppy and does not run smoothly. I’ve tried restarting the browser and checking my internet connection, but the issue continues. This problem only happens in Firefox, not in other browsers.

Hello,

I am having an issue with my Bluetooth headphones (Sennheiser HD 450BT) in Firefox on Windows 11.

The headphones are properly connected to Windows and work correctly with other browsers (Edge, Chrome).

Windows shows the headphones as the default output device (stereo), and test sounds play through them.

However, in Firefox, the audio does not go through the headphones. Instead, it plays very loudly through the laptop speakers.

The problem started today; there were no issues for about a year.

I have tried reconnecting/reinstalling the headphones, but it did not help. Drivers are also up to date.

Could you please advise how to make Firefox correctly use my Bluetooth headphones as the audio output device?

Thank you for your assistance.

Whenever I use Google Meet in the Firefox browser, it works well at first people can hear me. However, for a few seconds, my microphone suddenly cuts out, and I have to raise my voice for it to work again. My microphone remains enabled and does not disconnect when the audio cuts out, but people are still unable to hear me. I have already set my microphone to 'Always Allow' instead of 'Allow Temporarily, but the problem persists.Can anyone help me with this

There's already a decent help article about how to block videos from autoplaying:

https://support.mozilla.org/en-US/kb/block-autoplay

The problem is, it works haphazardly. Even if my default for all web sites is "Block Audio and Video", on some web sites (not all) embedded videos still start playing as soon as they scroll into viewport.

Some have adviced to delve into about:config and set media.autoplay.blocking_policy to 2 (default is 0) and, based on quick testing, that actually seems to help but why exactly does it help? If privacy settings already have a setting to block autoplay, why does that particular configuration change make it work as it is supposed to work?

Running Floorp 12.5.0 (Firefox offshoot) on Win11, if that helps.

For a couple of days now Instagram linked videos won't play here. Actually some of them will -- my own reels and anything linked with that button that looks like a movie 'clapper'. But videos that show the triangular arrow pointing to the right, nothing happens when you click. Not sure if this is a FF issue or maybe something changed at Instagram. Did a google search and nothing came up.

For the last two years the issues with video stutter have been worse and worse for me. I don't know if it is because of a different codec the video is using, but if it was I would expect the fans to ramp up from trying to decode it. Instead, my laptop stays always silent, but the video laggs like crazy when I want to play it at native 1440p.

I cannot view or change the video codec, since the current issue happens on a platform (herohero.com) other than youtube.

Hello Mozilla Support Team,

from yesterday playback speed on youtube is not working. When I open the same video with Edge playback speed is available.

Could you please check and rework?

Thanks in advance.

Many greetings Stefan

When I am watching a YouTube video and switch tabs, sometimes, on return to the YouTube tab, I have no sound. It is not muted. The system sound is fine. This does not always happen. I can switch tabs and still hear the sound. Then switch back and no sound. The video is not paused. I've tried pausing and playing the video, still no sound. Refreshing the tab doesn't help Where do I go to turn the sound back on? Win11, Firefox v144.02 64 bit.