User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:71.0) Gecko/20100101 Firefox/71.0

Steps to reproduce:

Playing any video on YouTube.

Actual results:

Since the Sept 12 Nightly update, video playback has glitched, where a few times per minute, the video will stop playing back, but the audio will continue.

Switching to safe mode allowed video to play back properly, however turning off extensions in normal mode still saw the glitching happen.

Turning off hardware acceleration allowed the video to play back properly, as far as I have tested thus far.

Video card: NVIDIA GeForce GTX 660
Driver version: 25.21.14.1896 (2-8-2019)

Expected results:

Video should play back without interruption.

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

It's something with focus. Clicking outside video, will freeze it in few seconds, clicking inside or moving mouse over player will keep it playing.