[pulseaudio-tickets] [PulseAudio] #208: Stuttering and other effects in long-running pulseaudio

[PulseAudio]

#208: Stuttering and other effects in long-running pulseaudio
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 Reporter:  kalaleq                   |       Owner:  lennart
     Type:  defect                    |      Status:  new    
 Priority:  normal                    |   Milestone:         
Component:  daemon                    |    Severity:  major  
 Keywords:  stuttering garbled sound  |  
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 I'm experiencing a problem with garbled sound.  It sounds vaguely similar
 to ticket #201, but somewhat different, in that i cannot rectify the
 problem by restarting the client, only by restarting the PA daemon.

 Starting with 0.9.7, and continuing with 0.9.8 - it never happened with
 0.9.6 - if i leave MPD playing for a long time, the audio begins
 stuttering, which persists until i restart PA.  I had not previously
 measured what `a long time' means, but in my latest test it took just
 under two hours.  My feeling is it is a bit random, and sometimes happens
 more quickly, but i cannot be sure without testing further.  I believe it
 also happened once while listening to a long mp3 in audacious, so i don't
 believe it is MPD-related.

 I'm testing on an athlon 1800+ with 640MB of RAM, using an on-board CM8738
 (cmipci) - i have other hardware configurations available but have not yet
 had occasion to test on those.  I have PA set up as pcm.!default in my
 /etc/asound.conf.  It is actually running on top of dmix, a trick i
 discovered that will allow me to use passthrough mode (spdif) for watching
 movies, even while PA has the sound device open - as long as i don't play
 any other sounds while watching.

 It basically sounds like the audio is `stuttering' - a very rapid
 interruption and popping through which the original sound is certainly
 still understandable.  It's not especially loud, just stuttering at about
 the same perceived volume as the stream itself.

 At first i thought it sounded like a load issue, that perhaps PA 0.9.7+
 used more CPU than the previous versions and wasn't able to keep up.  But
 that doesn't seem to be the case; both before and after the garbling
 starts, PA's CPU utilisation hovers around 6% in top.

 If i stop the client, then restart, i still hear the same effect.
 Likewise if i kill the client's connexion via the PA manager, then restart
 it.

 The `stuttering' effect remains until i restart PA itself.  After
 restarting, CPU and memory usage as reported both by top and by the PA
 manager statistics seem unchanged, but the stuttering effect is gone.

 Interestingly, this time, when i tried to start *another* client, either
 while MPD was still playing, or after pausing/stopping MPD, or even after
 restarting PA, i could not.  I tried audacious, mpg123 and aplay, none of
 which could open the audio device.  The command-line clients showed me the
 following message:

 *** PULSEAUDIO: Unable to create stream.

 MPD continued to be able to create streams, even after restarting it, but
 the other three could not.  This persisted until i rebooted the machine -
 after which i could run all four clients simultaneously again with no
 problems.  I had not noticed a problem like this before, but i may just
 never have tried.

 Please let me know if there's anything else i can do to help diagnose the
 problem!  I'll continue running PA 0.9.8 on this and other machines for a
 while, and add to this ticket if i notice anything new.

-- 
Ticket URL: <http://pulseaudio.org/ticket/208>
PulseAudio <http://pulseaudio.org/>
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