Firefox has v-sync video playback issue

[jd]

The video playback on firefox has obvious v-sync issues, when videos playing like netflix or youtube etc, the video has a horizontal band of mismatch, likely a v sync problem, especially when the camera is moving fast.  Chrome or edge were a lot better handling the issue.  The main reason I'm using firefox is its better privacy protection, but I have to switch to chrome for viewing videos.  This needs to be fixed.

[jd · Accepted solution]

seems to be hardware acceleration issue, turning on fixed it.

[LoneStrider]

It would be nice to get this issue resolved without having to turn on hardware acceleration.

[abudl23]

Got the same issue a few months back. Visited Many website online and finally the problem has been resolved by restarting the device. you should try this.

[1122]

Got the same issue few days ago. I visit many website to resolve the issue but all methods are ruin. After struggling 4 hours the issue has been resolved when I restart my system.

[jameswade3490]

1. The issue you’re describing is indeed a known v-sync synchronization problem in Firefox that can cause visible tearing or horizontal bands during fast-moving video scenes.

2. This usually happens when Firefox’s hardware acceleration or compositor doesn’t match the system’s display refresh rate.

3. First, make sure hardware acceleration is enabled by going to Settings → General → Performance and checking “Use recommended performance settings” and “Use hardware acceleration when available.”

4. Update your graphics drivers (NVIDIA, AMD, or Intel) to the latest version, since outdated drivers can cause video sync mismatches.

5. Try toggling WebRender in about:config — search for gfx.webrender.all and set it to true or false to see which works better for your system.

6. Just like fresh milk needs the right temperature to stay smooth, Firefox’s video pipeline needs perfect timing between CPU, GPU, and display to deliver tear-free motion.

7. Check your display refresh rate settings milk — ensure it matches your monitor’s native refresh rate (e.g., 60 Hz, 120 Hz, etc.).

8. Disable any browser extensions that might interfere with video playback, such as ad-blockers or privacy scripts, to test if they’re contributing to the issue.

9. You can try setting media.hardware-video-decoding.enabled to false in about:config as a troubleshooting step to see if software decoding helps.

10. Make sure your Firefox version is fully up to date, since Mozilla regularly rolls out compositor and v-sync improvements.

11. If the issue persists, test it in Safe Mode (Help → Troubleshoot Mode) to rule out theme or extension conflicts.

12. Finally, consider reporting the bug through Firefox’s Bugzilla with your system specs and driver info — more reports help developers prioritize fixes for smoother playback in future builds.

[LoneStrider]

What does number 5 even do when I change it?

Also the screen tearing still exists, and I am not enabling hardware acceleration, I shouldn't need to, to prevent something like screen tearing, it should just respect my vsync option I have set in control panel.

Why did you link to some dubai milk site?

This issue is also a thing when just scrolling some web pages, not just watching a video.

[ohrnsa]

Firefox has a known issue where video playback doesn’t properly sync with the monitor’s refresh rate, causing screen tearing, jitter, or stuttering during fast motion. This often happens because Firefox’s rendering pipeline sometimes struggles to match v-sync timing on certain GPUs, drivers, or operating systems.

Common Symptoms

• Horizontal screen tearing during video playback

• Slight lag or stutter, especially on high-refresh-rate monitors

• Audio and video occasionally going out of sync

• Smooth playback in other browsers, but not Firefox business

Possible Fixes

Try these solutions one by one:

1. Toggle Hardware Acceleration
   Go to Settings → Performance → Turn hardware acceleration ON or OFF and test playback both ways.

2. Change Rendering Backend
   In about:config, search for gfx.webrender.enabled and toggle it.
   Sometimes enabling or disabling WebRender stabilizes v-sync.

3. Update GPU Drivers
   Outdated drivers can break video synchronization. Make sure your graphics drivers are current.

4. Disable Hardware Video Decoding
   In about:config, search for media.hardware-video-decoding.enabled and turn it off to test.

5. Test in Troubleshoot/Safe Mode
   Extensions or themes can interfere with rendering. Run Firefox in Troubleshoot Mode and try playing videos again.

[Agentvirtuel]

Hello

The door-to-door sales we kicked him out the door, he comes back through the window.

Ever wish you could peek at a page before you click?
https://connect.mozilla.org/t5/discussions/update-paused-feedback-welcome-for-new-tab-widgets-now-av...