Youtube videos lag at full screen (Firefox 55.0.1 64 Bit)

[Asgard]

It doesnt matter what resolution I choose, once I enter full screen I get the choppy playback. The videos play normally when not in full screen on any resolution.

My only other browser is MS Edge and I dont get this problem at all.

Im using Windows 10 64-bit.

Any help is appreciated.

[DanRaisch]

Does the same thing occur if you launch the application in Mozilla Safe Mode? http://kb.mozillazine.org/Safe_mode

[Asgard]

Does the same thing occur if you launch the application in Mozilla Safe Mode? http://kb.mozillazine.org/Safe_mode

I tried several videos in safe mode like you suggested and they all played normally.

What does this mean?

[DanRaisch]

When things work properly in Safe Mode but not in Standard Mode it often indicates that an installed extension is causing problems. When the issue is video display, it could also mean that your system can not accommodate Firefox's default hardware acceleration setting. To check the latter, use menu path Tools->>Options->General->Performance section and uncheck the setting to "Use hardware acceleration when available". Close and restart Firefox and see if the video lag is still present. If not, you're done. If it is, then:

Try disabling all extensions but one and then close and restart the program. (Disable them by using menu path Tools->Addons->Extensions->click on "Disable" for every extension but one.) See if the problem is present. If not, enable an additional extension and close and restart the application. Repeat this procedure until the problem reappears. The last enabled extension will be the cause of the problem.

[Asgard]

When things work properly in Safe Mode but not in Standard Mode it often indicates that an installed extension is causing problems. When the issue is video display, it could also mean that your system can not accommodate Firefox's default hardware acceleration setting. To check the latter, use menu path Tools->>Options->General->Performance section and uncheck the setting to "Use hardware acceleration when available". Close and restart Firefox and see if the video lag is still present. If not, you're done. If it is, then:

Try disabling all extensions but one and then close and restart the program. (Disable them by using menu path Tools->Addons->Extensions->click on "Disable" for every extension but one.) See if the problem is present. If not, enable an additional extension and close and restart the application. Repeat this procedure until the problem reappears. The last enabled extension will be the cause of the problem.

You were right about my system not being able to properly use hardware acceleration. There was a driver update for my graphics card which had a fix for my specific problem. I updated the driver and it solved the problem.

Thanks for your help.

[DanRaisch]

You're welcome.