[pulseaudio-discuss] Pops/Crackles Messing up my audio...

Nasa nasa01 at comcast.net
Thu Aug 11 10:09:25 PDT 2011



----- Original Message -----
> ----- Original Message -----
> > 'Twas brillig, and Nasa at 07/08/11 21:26 did gyre and gimble:
> > > Hi,
> > >
> > > I was hoping I could get some help troubleshooting some audio
> > > quality issues I am running into.
> > > Specifically, I am getting a lot of *pops/crackles* when I play
> > > audio files. It shows up when I
> > > move from 2-channel to 4/5 channel audio (via pauvcontrol) - I am
> > > using a USB X-FI sound-card with
> > > the Meego IVI.
> > >
> > > I have tried changing the resample method (going from ffmpeg to
> > > high-quality) and setting tsched=0,
> > > neither making any noticeable difference.
> > >
> > > The only things I saw in /var/log/messages that seemed relevant
> > > was:
> > > messages:Aug 6 16:59:26 localhost pulseaudio[570]: alsa-sink.c:
> > > ALSA
> > > woke us up to write new data to the device, but there was actually
> > > nothing to write!
> > > messages:Aug 6 16:59:26 localhost pulseaudio[570]: alsa-sink.c:
> > > Most
> > > likely this is a bug in the ALSA driver 'snd_usb_audio'. Please
> > > report this issue to the ALSA developers.
> > > messages:Aug 6 16:59:26 localhost pulseaudio[570]: alsa-sink.c: We
> > > were woken up with POLLOUT set -- however a subsequent
> > > snd_pcm_avail() returned 0 or another value < min_avail.
> > >
> > > And this was spout out of dmesg
> > > [ 21.857184] ALSA sound/usb/mixer.c:2110: status interrupt: c0 00
> > > [ 21.897058] ALSA sound/usb/mixer.c:2110: status interrupt: c0 00
> > > [ 21.961062] ALSA sound/usb/mixer.c:2110: status interrupt: c0 00
> > >
> > > I have already eliminated the speakers and the amp (played music
> > > from a different source and
> > > they sounded fine).
> > >
> > > Let me know what else I should post (I could record the sound, if
> > > that would be useful).
> > >
> > > Thanks in advance,
> >
> > While this could be an issue in the alsa driver itself, can I ask if
> > you're applying any volume changes to your streams or sink?
> >
> > There could be a problem with optimized paths for software volume
> > adjustments. You can disable these optimisations via a special
> > environment var: PULSE_NO_SIMD=1
> 
> Col,
> 
> So I added
> 
> export PULSE_NO_SIMD=1
> 
> into my .bashrc file and rebooted. From the terminal
> "echo $PULSE_NO_SIMD" came back '1' -- however, that didn't
> make any difference in the pops/crackles I am hearing :{
> 
> Nasa
> 
> 
So,

Is there anything else I can check, or should I place a bug report
for ALSA?

Nasa


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