[mythtv-users] What do I have to do to get HD working?

Kevin Kuphal kuphal at dls.net
Sat Apr 15 21:31:00 UTC 2006


Kevin Kuphal wrote:
> I'm about at my wits end.  I just purchased a P4 3.2ghz HT to do HDTV 
> playback in software but no matter what I do, I get continual studdering 
> and "Video X frames ahead of audio" on my HD playback material.  This 
> happens on my MX4000 PCI video card system, my ATI 9100 IGP video card 
> system, and my Unichrome Pro video card system. 
>
> Everything I read said that a P4 3.2 is enough to do HD but nothing I do 
> can get it to work.  I'm running the 2.6.15 smp kernel but that almost 
> seems to make it worse.  With the non-smp on my Unichrome system it 
> plays back but only at about 17-20 fps.  With the smp kernel, it does 
> the 29-30 but jumps and skips complaining about the video ahead of audio.
>   
To follow up on my own findings:

1)  The P4 3.2 is enough of a processor to do HD playback.  Once I 
dropped my Nvidia 6200 AGP from my gaming PC into the system, playback 
was fine.  The definitive answer is that the PCI card cannot handle 
playback, nor can the Unichrome Pro IGP or the ATI 9100 IGP.   I found 
occasional glitches with Standard playback and kernel deint but libmpeg2 
worked great.

2)  The Extra audio buffering was distorting things.  With it disabled, 
the 17-20fps playback was really what the system could deliver while 
with it enabled, it became choppy. 

I plan to pick up another AGP card for my frontend which should fix this 
permanently.  Thanks all for your help.  I hope my trials helps people 
when making hardware decisions for HD


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