I-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.

Particularly on US news sites, inline / spot videos still auto-play despite the FF preference set to block audio and video. Mercifully, audio isn't playing. This seems to be a fairly recent problem since the last couple / few updates; not really certain.

I cannot get audio to play on the browser. I've gone into settings and the default says that audio should be on for all websites. However, Youtube, facebook, instagram, etc., won't play audio. Audio plays on other browsers (Chrome, Edge). what must I do to get audio working?

Context

While playing YouTube videos in Firefox, intermittent crackling appears after a few minutes of playback. This report documents detailed testing that demonstrates the issue is not related to the DAC, USB interface, or system hardware, and is exclusive to Firefox.

2. System Configuration

CPU: AMD Ryzen 5 5600X @ 43 °C

RAM: 64 GB DDR4 dual-channel (16-20-20-38 @ 1572 MHz)

Motherboard: ASRock X570 Phantom Gaming 4 (AM4) @ 54 °C

GPU: NVIDIA GeForce RTX 3050 (audio drivers disabled, audio hardware off)

Monitors: LG HDR WFHD 2560x1080@60Hz and IPS236 1920x1080@60Hz

Storage: Multiple SSD and HDD SATA drives (500 GB – 2 TB)

Audio: Realtek High Definition Audio disabled; iFi nano/UNO DAC connected via USB with power filtering, using Exclusive Mode / ASIO

3. Tests Performed 3.1 DAC and USB Validation

Continuous playback of PCM 384 kHz/24‑bit and DSD256 via Roon/ASIO.

Duration: over 25 minutes of uninterrupted DSD256 playback.

Result: no crackling, pops, or errors.

Conclusion: DAC, firmware, USB cables, ports, and power supply are fully operational; heavy data load does not cause errors.

3.2 Browser Comparison

Chrome (YouTube, identical conditions): continuous playback without crackling.

Firefox (YouTube, identical conditions): crackling progressively appears minutes into playback, temporarily disappearing when the video is paused.

3.3 Isolation of Variables

USB motherboard ports and original drivers fully tested.

GPU audio drivers and hardware disabled.

Windows Shared Mode off, Exclusive Mode enabled.

Predefined audio formats set according to DAC preferences.

USB power management disabled.

DAC temperature stable; no overheating observed.

4. Technical Conclusion

Hardware: DAC, USB, cables, power, firmware, and GPU are not the cause of the crackling.

Operating System: Windows 11 is correctly configured; Exclusive Mode / ASIO works without errors.

Browser: Firefox is the only element consistently reproducing the issue.

Most Likely Cause: Firefox’s buffer management and audio sandboxing interacting with Windows, causing intermittent interruptions in audio flow.

Summary: All hardware and OS factors have been tested and validated: DAC, USB, cables, power supply, firmware, GPU, and temperature do not produce crackling. The only consistent factor is Firefox, making this a software-bound issue.

Engineering Note: This diagnosis conclusively demonstrates that the intermittent audio crackling on YouTube is caused exclusively by Firefox on Windows 11, independent of DAC or USB hardware. The issue should be investigated at the browser level, specifically how Firefox handles continuous digital audio streams and buffers on Windows.

Tell me why I have no sound on Firefox and how to fix it. I do have sound on DuckDuckGo and AVG Secure Browser. I have checked my sound setting 55% and not muted. I have shut down and started laptop, still no sound. I checked Firefox updates and am good.

My sound does not work when using Firefox. But when I switch to the troubleshooting mode in the "Help" menu, the sound works normally. I did not make any changes to sound settings. Sound was fine last night and did not work when I woke the computer up this morning. I am using Windows 11. Going from troubleshooting mode back to normal mode causes the sound to stop working again.

subtitles appearing on all YouTube content, even though subtitles turned off. I have toggled the cc button and also subtitles in settings with no luck. The cc box does work to turn subtitles in not YouTube videos.

Unable to play a video on Hulu with my own Hulu account, which I have had no issues in the past doing, even with all my ad blockers and trackers enabled (Privacy Badger, uBlock Origin, AdBlocker Ultimate, Ghostery, and Malwarebytes). I have tried disabling all of the above extensions, refreshing the website and still no luck. I have also followed the instructions Hulu guides me to via a link on the screen (see attached screenshot) to their help page https://help.hulu.com/article/hulu-power-cycle?utm_source=hulu&utm_medium=error-message&utm_campaign=video-02 None of these have helped either. My internet speed is fine, I checked it through 3 different internet speed testers to verify Also checked my Wifi signal through our Google Home portal. I've searched online for solutions and haven't found anything new to help or in the Mozilla Support forum. My computer/laptop is up to date on all updates and software. Appreciate any support, thank you!

After a Windows 11 update my Firefox browser no longer has any audio. The sound is turned all the way up in the Sound Mixer and I have no Bluetooth devices connected. After it initially happened I connected my Bluetooth earbuds and it worked for a few minutes before it too lost audio.

I have audio on all my other applications.