[mythtv-users] Confused about mythtv settings, X settings, filters and CPU usage

Phill Edwards phill_edwards at hotmail.com
Thu Dec 9 13:50:32 UTC 2004

I'm trying to find a decent compromise between the quality of the 
recordings/playback and the amount of CPU used. I have investigated this but 
I don't really understand the different settings and options, so I have a 
few questions. My system is FC2, with 2.4GHz Celeron CPU, 256 MB DDRAM and a 
Pixelview bttv capture card.

1) I'm in Australia so I'm using PAL. I read that the recording dimensions 
for PAL should be 720 wide x 576 high, but when I do this I notice that it 
uses a lot more CPU (20% more) and the picture quality improvement is only 
marginal. Is 720 x 576 right? What do most people set this to on PAL 

2) Do the mode sizes in xorg.conf affect the TV quality? Mine are Modes 
"1024x768" "800x600" "640x480". Does it matter that this is different to the 
720 x 576 mentioned above?

3) What is the right PAL setting to put in xorg.conf for Australia? I have 
Option "TVStandard" "PAL-B" - is PAL-B the right one?

4) With filters, do you set them in the channel recording settings, or the 
global playback settings or both? And if in both, do the filters used in 
playback have to be the same as those for recording?

5) Are there any other things I should be looking at to improve the picture 
quality without sacrificing CPU. (The reason I'm concerned about CPU is that 
tonight I was watching a previous recording while another show was 
recording, and the show that was recording came up very badly - dropped 
frames, poor audio/video sync etc. So I assumed that playback stole CPU 
cycles from the recording which made it poor quality, and I want to avoid 


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