[mythtv-users] Slow/choppy playback problem (not the usual ones, either!)

[Joshua M. Thompson]

On Fri, 2004-10-15 at 23:31 -0400, Michael T. Dean wrote:
> On 10/15/2004 08:32 PM, Joshua M. Thompson wrote:
> 
> >Ok as expected switching to AGP did not help. Now the X CPU usage
> >between mplayer and mythtv is now even greater; "mplayer /dev/video0"
> >eats up 6.6% CPU (down from 30%) and "mythtv" eats 60% (down from 70%).
> >
> >Here is another datapoint: I take an XviD file stored on my NFS server
> >and play it with mplayer. It plays great. I then play it with mythtv and
> >get the same stuttering audio and video. The output from mythtv is about
> >the same as watching live TV except it doesn't connect to the backend
> >(obviously):
> >
> >2004-10-15 20:24:41 Opening OSS audio device '/dev/dsp'.
> >2004-10-15 20:24:41 Audio fragment size: 4096
> >2004-10-15 20:24:41 Using XV port 105
> >2004-10-15 20:24:41 Changing from None to WatchingPreRecorded
> >2004-10-15 20:24:42 prebuffering pause
> >2004-10-15 20:24:42 prebuffering pause
> >2004-10-15 20:24:43 prebuffering pause
> >2004-10-15 20:24:43 prebuffering pause
> >
> >I'd say this at least rules out the backend. The problem is in the
> >frontend player somewhere. Not sure where to go from here; is there some
> >option I can flip or something I can change and recompile?
> >
> >Oh and since my mplayer config file by default uses ALSA directly I
> >tried the same experiments with "mplayer -ao oss" and got the same
> >results, so I don't think it's the sound drivers.
> >  
> >
> I still think it's the audio configuration.  (I can be a bit stubborn 
> that way--ask anyone on the list. :)  If you don't mind humoring me, 
> please provide your sound card type, ALSA version, .asoundrc file, and 
> sound-related lines from /etc/modprobe.conf.

Not using an .asoundrc at the moment as I haven't needed one. Module
configuration looks like this:

alias snd-card-0 snd-usb-audio
install snd-usb-audio /sbin/modprobe --ignore-install snd-usb-audio && /usr/sbin/alsactl restore >/dev/null 2>&1 || :
remove snd-usb-audio { /usr/sbin/alsactl store >/dev/null 2>&1 || : ; }; /sbin/modprobe -r --ignore-remove snd-usb-audio
alias snd-card-1 disabled
install snd-intel8x0 /sbin/modprobe --ignore-install snd-intel8x0 && /usr/sbin/alsactl restore >/dev/null 2>&1 || :
remove snd-intel8x0 { /usr/sbin/alsactl store >/dev/null 2>&1 || : ; }; /sbin/modprobe -r --ignore-remove snd-intel8x0

The main card is a SB MP3+ USB (*not* the Audigy version). The extra
card is the onboard audio, which I am not using as it does not have
optical output.

Thinking it might be the USB sound I tried re-enabling the secondary
sound card and reconfiguring MythTV to use /dev/dsp1. Aside from not
hearing sound (since it's not hooked up on that card), the results were
the same.

I'm stubborn too and I really think it's something related to the way
MythTV sets up X. :) I can't imagine anything else that would cause the
X server process to burn 8-10x as much CPU watching video in MythTV as
opposed to mplayer. With that in mind I am currently trying another
lead, which is recompiling without the XvMC support. If that doesn't
help I'll try turning off the OpenGL Vsync support.

-- 
Joshua M. Thompson <funaho at jurai.org>