issue with VP8 and Ogg video

Jan Beich jbeich at
Thu Jun 28 19:30:51 UTC 2012

Jan Beich <jbeich at> writes:

> AN <andy at> writes:
>> Hi:
>> I want to report an issue I have playing HTML5 video in Firefox.
>> - if you pause or stop a video it takes time (10-30 secs) before the sound 
>> stops playing
>> - after viewing a video Firefox cpu utilization pegs at 100% and stays 
>> there until you exit firefox and restart it.
>> I have seen this problem before with Adobe Flash, it seems that it has
>> been fixed with Flash.  Now it happens with VP8, and Ogg.  I would
>> like to help to troubleshoot this if I can.  I am not a developer,
>> just a lowly user.
> [...]
> Try to test[1] on www/linux-firefox to verify if this a platform
> specific bug.

I've pushed a few options to choose audio backend in Nightly port. It
should help debug audio issues like this one. And from my limited
testing on youtube (some could be local issues):

  alsa->oss   + cubeb  = no sound (but aplay works)
  alsa->oss   + sydney = fast-forward video
  alsa->pulse + cubeb  = fast-forward video + noise
  alsa->pulse + sydney = works fine
  pulse->alsa + cubeb  = works fine
  pulse->alsa + sydney = busy wait during pause (like native OSS)
  pulse->oss  + cubeb  = works fine
  pulse->oss  + sydney = busy wait during pause (like native OSS)
> In my case on Nightly after pause takes effect (a few *seconds* after
> hitting it) firefox cpu usage ramps up to 100% in audio_callback around
> pthread_mutex_unlock, i.e. sydney_audio_oss.c:459.

> And if I close the tab while sound still plays (whether or not I hit
> pause) the bug would not appear.

Nevermind, cpu utilization often drops to normal after closing the tab,
it just takes time (around 10s here). Sometimes opening another tab with
video and closing it shortly after helps.

> [1] if you manage to make sound work (I haven't) despite linux aplay(1) working fine;
>     a few related diffs attached, may or may not make a difference

Correction, I do have sound working fine on linux-firefox up to 13.0 and
even on Nightly if I disable libcubeb. But as threading in glibc->linuxulator
works differentry than our libthr results aren't useful.

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