[mythtv-users] 800 MHz P3 for HDTV

Rod Smith mythtv at rodsbooks.com
Sun Mar 4 02:10:59 UTC 2007

On Saturday 03 March 2007 16:39, stan wrote:
> It seems if the display card is doing all the decoding work,

This is a false premise. When using a regular video card and XvMC, the video 
card does *NOT* do "all the decoding work," or even close to it. XvMC enables 
the video card to do **SOME** of the decoding work, but by no means all of 
it. My understanding is that this isn't a limitation of the speed of the 
video card, but of what types of operations XvMC supports vs. what types of 
operations must be performed to decode MPEG-2 video. That is, some types of 
computations must be performed by your CPU, given the designs of MPEG-2 and 
XvMC. My guesstimate is that XvMC offloads 30-50% of the decoding work, based 
on the system loads I've seen with and without XvMC.

> Is there a chance if I
> 	- Don't record while playing back
> 	- Don't run any servers on it
> 	- Don't do any remote file access

None of these measures will help. They might help if you have a ~3GHz system 
that's on the edge, but for an 800MHz system they're about as much use as 
fairy wings on a cement truck, to quote Michael Garibaldi from "Babylon 5."

Rod Smith

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