Does not support negative delay (placing the audio slightly ahead of the video), which was the sole reason I installed it in the first place. Pressing the -100 or -500 buttons when the delay is at 0ms does nothing.

Please don't limit it to just 5000ms, as there are videos where the desynchronization is greater than that number of ms.
Also, please ensure that the extension’s theme matches the current YouTube theme (dark/light), and it would be even better if there were an option to customize the theme.

Extension does what it says and works well, but only gets 4 stars because the smallest delay you can adjust is 100ms, which is a HUGE delay... So it can often be impossible to get things synced perfectly.

Author should really add a field to manually type in an offset value, or add 10ms increment buttons as well.

this plugin cannot correct audio delay. if set -500 ms or +500 ms result is same . it play 0.5 seceonds video then sound start which is wrong. it delay only the sound which not need on high . i use sessionwire From SW virtual audio driver to play audio or native uad audio driver. best is disable it because for bluetooth audio or other high latency audio devices you need delay the video and not the audio. plugin developers should ask firefox team to add video delay feature for the youtube and other video players that use HTML 5