User Agent: Mozilla/5.0 (Windows NT 5.1; rv:37.0) Gecko/20100101 Firefox/37.0 Build ID: 20150129200438 Steps to reproduce: This bug occurs at least on Firefox 36 (beta) and Firefox 37 (Developer) on Windows 7 and 8 (tested) Open any mp3, m4, avi, Youtube or any HTML-Player that plays audio/video. Actual results: The audio and video are asynchron. Video and audio: The Video is faster than the audio Only audio: Audio is faster than the counter (When the audio is ended, the counter is in the middle) Expected results: The audio and video should be synchron and the counter should work right.

Min: Can you provide a link to a video which has this behaviour? Thanks!

@cpearce As I said, in any video/audio this bug occurs. I think, the counter of Firefox counts to slow. Example: https://www.tagesschau.de/multimedia/audio/audio-10795.html Video to show bug: https://alme.pf-control.de/F_bug.mp4 ~Min

It looks like that the Firefox update 36.0b (from 10.02.2015) solved this bug. Yesterday I found out, that my USB 2.0 Headset produced this bug. When I used my built-in (Laptop-)speakers it works. I will continue to monitor it.

Let's keep a track in newer bug which get "+" tracking status and devs attention.