[mythtv-users] Choppy Playback & prebuffering message

Nate Crosno nate at crosno.net
Thu Apr 13 21:30:53 UTC 2006


Hi All,

I'm having lots of frustration getting content to play back smoothly. 
Sorry for the noob question. I'm sure you pros get this all the time.  
I've been building up this myth box for about a couple weeks and cannot 
get anywhere close to smooth playback.  I can usually sort these things 
out on my own, but am loosing my patience. I've been using Linux on and 
off since about 1998 and am a web developer by trade.  Most of my 
experience is with back-end server type setups.

Here is my hardware:
 - Dell Dimension 2400
 - Celeron 2.2Ghz
 - 756MB RAM
 - ATI HDTV Wonder capture card.
 - Radeon 7000 PCI 64MB  (right now set to 1024x768 @ 60hz, dri and drm 
seems to be loading fine according to the Xorg.0.log)
 - 160GB Seagate drive UATA 7200RPM (dma enabled)
 - On-board Intel audio
 - Right now hooked up to a Dell 15" LCD monitor via VGA, but shooting 
to hook it up to my Sony 50" LCD rear projection via the DVI port.

Software:
 - Gentoo linux kernel 2.6.15-gentoo-r1 (recompiled several times over 
the past couple days to get things working)
 - problem happens on both Gnome and blackbox
 - latest mythtv build via 'emerge'


When trying to view recorded content or watch live TV (either SD or HD) 
I get the following:
  - Pauses every 1-2 seconds (speeding up, slowing down, etc), this 
includes breaks in the sound.
  - in the mythfrontend terminal window I see lots of messages about 
'prebuffering pause'
  - big pink vertical bar along the right edge of the content (on SD 
content)
  - if I turn off the sound (set the sound device to something invalid 
in myth), then it seems to just play slowly
  - while only mythbackend is running and recording HD content 'top' 
shows only about 10% CPU usage.
  - while trying to watch live tv or recorded content, the CPU gets 
maxed out:
       0% idle, 60% mythfrontend, 27% X
       0% swap in use

I'm hoping something here will catch your collective eye.

I've tried many of the various settings like aggressive sound buffering 
to no avail.

Thanks a million!
-Nate


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