There is always a small delay (usually about 400ms) when playing audio via BT, even with BT low latency there is a short delay of a few tens of milliseconds. If the sound is really out of sync (seconds or more) then likely something went wrong with syncing the audio. I think it would more easily happen that the video would lag as decoding audio shouldn't be a problem unless Firefox spends that much time on decoding the video that there isn't get enough processor time to process the audio.

You can see device latency information by visiting about:support#media in the address bar. There is an arbitrary 100ms playback latency which you can adjust in about:config by creating media.cubeb_latency_playback_ms (Number) (1-1000).

WARNING from the moderator team: Changing Firefox preferences from the about:config page can sometimes break Firefox or cause strange behavior. You should only do this if you know what you're doing. Please read Firefox Advanced Customization and Configuration Options to learn more.

Thank you cor-el and zeroknight for the response. Agreed with the latency part which causes lag but what about when the audio stops. It is more common in bluetooth audio devices. When i am using the wired devices the sound still comes but in bluetooth devices i have to disconnect and reconnect the audio device.

Is there any way how can i can i find and analyse raw data in browsing session. I was able to replicate the issue in other devices too. The precipitation of no sound issue occur when I play video at speed more than 2x. The precipitation occurs when it goes beyond 3x, 4x, 5x.

The lagging precipitation occurs when clicking on the seek bar but this issue was not present before.

but this issue was not present before.

You can test daily builds of Nightly to find when it broke by manually downloading them or running mozregression.

Hello people thanks for all your help. The real culprit is echo dot and other alexa devices which I am facing the issues. Beats audio and other devices are working fine. Thanks all the people cor-el, zeroknight and dropa.