[mythtv-users] Gravely audio -- now with buffer underrun!

[George Rom]

I didn't have this problem, but I got the ALSA:front tip from the myth
how-to (http://www.mythtv.org/wiki/Installing_MythTV_on_Fedora) - see the
last line in the guide. It also mentioned changing the mixer setting to
master from PCM. Worth a try - I'm not too experienced with this stuff so
I'm grasping. Hopefully someone will have more insight.

On Fri, Jan 22, 2010 at 7:47 PM, steve <networks1 at cox.net> wrote:

>  >Now that I have playback audio working on my system, I notice there is
> terrible audio quality.  This is hard to describe, but it’s “gravely,” like
> there are very frequent short drop-outs.  This happens not >only when I
> play back via Mythtv, but also when I play the mpeg via the Totem movie
> player in Gnome.
>
> >
>
> >To rule out the possibility that the capture device (HDPVR) is defective,
> I copied the mpeg file onto a windoze machine and played it, and the audio
> sounds fine.  To rule out some problem with the >audio hardware on the
> linux box I played a CD, which also sounds fine.
>
> >
>
> >So somehow the problem only occurs when playing the audio from mpeg
> files.  Mythtv is configured to use ALSA:front for output (ALSA:default
> wouldn’t work).  I don’t know if Totem uses that too.
>
> >
>
> >I realize this appears not to be a mythtv-specific problem (I also posted
> on the fedora list) but I was wondering if any other mythtv users have had
> this problem, and if so how they fixed it.
>
>
>
> Well I checked the frontend log and found additional information (below).
> This explains the intermittent dropouts of audio.  BTW the subject should
> have been “graveley” (though the situation is grave).  Other posts describe
> this sound as “crackely” or “stuttering.”
>
>
>
> Checking some other posts/wiki entries suggested that pulse audio might be
> the problem but when I uninstalled alsa-plugins-pulseaudio the audio quit
> altogether, so I reinstalled it.
>
>
>
> Tried “aggressive buffering” option.  No help so I turned it off.
>
>
>
> Not sure where to go from here.
>
>
>
> Steve
>
>
>
> 2010-01-22 17:22:02.861 TV: Attempting to change from None to Watching
> WatchingPreRecorded
>
> 2010-01-22 17:22:02.921 TV: StartPlayer(0, Watching WatchingPreRecorded,
> main) -- begin
>
> 2010-01-22 17:22:03.241 AFD: Opened codec 0x3223cc0, id(H264) type(Video)
>
> 2010-01-22 17:22:03.242 AFD: codec AAC has 2 channels
>
> 2010-01-22 17:22:03.242 AFD: Opened codec 0x32244b0, id(AAC) type(Audio)
>
> 2010-01-22 17:22:03.243 Opening audio device 'front'. ch 2(2) sr 48000
>
> 2010-01-22 17:22:03.244 Opening ALSA audio device 'front'.
>
> 2010-01-22 17:22:03.324 Mixer unable to find control PCM
>
> 2010-01-22 17:22:03.324 Mixer unable to find control PCM
>
> 2010-01-22 17:22:03.324 Mixer unable to find control PCM
>
> 2010-01-22 17:22:03.324 Mixer unable to find control PCM
>
> 2010-01-22 17:22:03.325 Mixer unable to find control PCM
>
> 2010-01-22 17:22:03.325 Mixer unable to find control PCM
>
> 2010-01-22 17:22:03.325 Mixer unable to find control PCM
>
> 2010-01-22 17:22:03.325 Mixer unable to find control PCM
>
> 2010-01-22 17:22:03.325 Mixer unable to find control PCM
>
> 2010-01-22 17:22:03.940 OSD Theme Dimensions W: 1280 H: 720
>
> 2010-01-22 17:22:04.694 TV: StartPlayer(0, Watching WatchingPreRecorded,
> main) -- end ok
>
> 2010-01-22 17:22:04.695 TV: Changing from None to Watching
> WatchingPreRecorded
>
> 2010-01-22 17:22:04.695 New DB connection, total: 3
>
> 2010-01-22 17:22:04.698 Connected to database 'mythconverg' at host: mythtv
>
> 2010-01-22 17:22:04.700 Realtime priority would require SUID as root.
>
> 2010-01-22 17:22:04.701 Video timing method: USleep with busy wait
>
> 2010-01-22 17:22:04.719 ScreenSaverX11Private: DPMS Deactivated 1
>
> 2010-01-22 17:22:05.014 WriteAudio: buffer underrun
>
> 2010-01-22 17:22:06.391 NVP(0): prebuffering pause
>
> 2010-01-22 17:22:06.419 NVP(0): prebuffering pause
>
> 2010-01-22 17:22:06.456 NVP(0): prebuffering pause
>
> 2010-01-22 17:22:06.476 NVP(0): prebuffering pause
>
> 2010-01-22 17:22:06.528 NVP(0): prebuffering pause
>
> 2010-01-22 17:22:06.568 NVP(0): prebuffering pause
>
> 2010-01-22 17:22:06.605 NVP(0): prebuffering pause
>
> 2010-01-22 17:22:06.647 NVP(0): prebuffering pause
>
> 2010-01-22 17:22:06.698 NVP(0): prebuffering pause
>
> 2010-01-22 17:22:06.733 NVP(0): prebuffering pause
>
> 2010-01-22 17:22:06.772 NVP(0): prebuffering pause
>
> [continues like this till I escape playback]
>
>
>
>
>
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