[mythtv-users] Jumpy playback with PVR-250?

Andrew Dodd atd7 at cornell.edu
Fri Jan 16 12:50:22 EST 2004


Quoting Scott Pouliot <spouliot at scpsoftware.net>:

> Not sure what the problem could be here, but I setup my Myth box probably 2
> weeks ago....and everything has been fine thus far.  Now today, while I'm
> watching either recordings or Live TV.....it starts skipping really badly
> every 2 or 3 minutes.  The video and audio both start going REAAAAALLLLY
> slow almost like every other frame is being played with a pause in between.
> Very odd...
>  
> I know the PVR-250 doesn't have a decoder for playback, but no recording is
> going on in the background at this point in time (other than the standard
> live TV buffering).  I've got my Live TV Recording profile set to MPEG2-PS
> with a bit rate of 2200 (max 4400)...audio set to 48.  Pretty low compared
> to the defaults (I think?)
>  
> My hardware:
>  
> Dell Dimension 4100 - PIII 933 w/ 384MB RAM
> 20GB Boot Drive
> 160GB Video Drive
> nVidia 32MB Video card (No TV-OUT)
> Hauppauge PVR-250 OEM ($88 one from eBay)
>  
> If I copy the output files from recorded shows and view them on my Windows
> XP box....everything is fine.  So it almost sounds like a CPU issue?  Since
> I'm a Windows guy at heart (but trying to convert) I'm not up on too much
> task troubleshooting in Linux yet....
Exactly which nVidia video card?  32M with no TV-out sounds like it might be a
GF3 or even a 2.  (Or maybe a 4MX???)

Are you using the stock X drivers that came with your distribution or the binary
drivers from nVidia?

A P3-933 should have no problem playing back DVD-resolution MPEG, unless
something is configured wrong.  Lack of Xv (Xvideo) support in the graphics
driver would be my primary suspect for this - I don't think mythtv's software
scaling/color conversion code is very optimized, as these days nearly everyone
has an Xv capable video card.

I don't believe the stock X drivers have Xv support.

Find your XF86Config file (Most likely is /etc/X11/XF86Config-4) and look to see
which video driver is being loaded.

If it's 'nv' you're using the stock driver
If it's 'nvidia' you must have downloaded the binary drivers at some point.

If you're using the binary drivers and have your colordepth set at 24 or 32 bpp
you should not be having problems.  Xv (especially XvMC) can be wonky at 16bpp.

The best NVIDIA cards for 2D video are the 4MX and FX series.  For some odd
reason 4 Ti-series cards only have motion compensation but no IDCT.  (Or was it
IDCT but no MoComp?)



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