[mythtv-users] Fwd: Audio/Video Stutter on one particular HD channel.

[Josh]

> Affected system is:
> Motherboard: Asus P5N7A-VM
> Onboard Video: Geforce 9300
> CPU: Core2Quad Q6600
> Sound: SB Audigy4 Value
> 1GB DDR2
> 40GB sata HD.
>
> Running Gentoo Linux,
> mythtv ~ # uname -a
> Linux mythtv 2.6.27-gentoo-r7 #6 SMP PREEMPT Tue Feb 10 11:10:31 CST 2009
> i686 Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz GenuineIntel GNU/Linux
> Mythtv version 0.21-fixes
> media-tv/mythtv-0.21_p19046  USE="aac alsa dvb dvd ieee1394 lirc mmx
opengl
> perl python xvmc (-altivec) -autostart -debug -directv -fftw -jack -lcd"
> VIDEO_CARDS="nvidia" 0 kB
>
> Audio is handled by Audigy4 value, through coaxial/spdif
> It's a standalone frontend, backend is on another machine.
>
> Apparently only one channel is affected, with the audio buffer underruns
> and dropping video frames to resync with audio.
> I have disabled audio by setting the audio device in mythfrontend to
> 'NULL', video playback is silky smooth, no dropped frames at all.
> Mabye it was a hardware issue, so I removed the Audigy4 and tried using
> onboard audio analog to my TV speakers. That resulted in worse
performance,
> with nearly all channels stuttering occaisionally.
>
> I've checked for conflicting IRQ's, my Audigy sound card is using IRQ 18
> and is not shared. Unsure about onboard, have not tested, it is disabled
> when the Audigy is installed.
> My 'mythfrontend -v playback' is located here:
> http://rafb.net/p/mkLEhL42.html
>

Dead link

> <http://rafb.net/p/mkLEhL42.html>
> I was playing back a recording from the affected channel while dumping the
> logfile, so all the errors at the end are related.
>
> A clip from the HD stream is hosted here:
> http://www.megaupload.com/?d=WX0KIIFC - Keep in mind that after about 1-2
> seconds, playback would stutter
>
>

Plays fine here.  No errors in the log.  Spdif output AMD 5400+ but  your
should be just as capable if not more so.

Not sure this will help but if you want to check your sound setup you can
check out a wiki I wrote.  That would be my next step.
http://www.mythtv.org/wiki?title=AllensDigitalAudioHowto

Allen

Thanks for the help, Allen. When I get home I'll playback the 'bad' channel
again and post the log.once more.

I have managed to get SPDIF working, but it was very flakey, I had to
disable onboard sound to be able to get output on my Audigy4 spdif.

The only way I could get analog sound working with my onboard chipset was to
run alsaconf, and then it would not persist after a reboot, had to run
alsaconf after every reboot. The actual audio itself was flakier on the
onboard chipset too, causing the stutter to become worse.

I'm gonna look at your guide, but does it sound logical that this issue is
particularly audio related? I think we're on the right track.
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