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

[steve]

>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]

 

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mythtv.org/pipermail/mythtv-users/attachments/20100122/731ce13d/attachment.htm>