[mythtv-users] Resolution

[Niels Dybdahl]

> 
> It seems as though the three profiles created by the Myth installation are
> all set to 480 x 480. When I tried setting the High Quality one to PAL 
> (768
> x 576) Myth just fails at recording (when I use that particular profile).
> 
> The rig is an Intel board with a P4 and PVR-350 with FC3 setup to Jarod's
> guide. I'm doing X over the TV-out but at present am using the hardware
> decoder rather than the new drivers (as I haven't worked out how to get
> these running properly with the newer x-driver)
> 
> Are there recommended settings for the different profiles? The 480 x 480
> setting gets me about 2Gig an hour which is manageable. Am willing to
> experiment with bigger file sizes if the quality is better.


For PAL you should definitely use 576 lines instead of 480 lines. 480 lines 
will give you a "jumping" playback.
720 pixels across is good, if you want to store the shows on DVD, but an 
analog signal from an antenna does not have much more than 480 pixels per 
line:
5 MHz bandwith=10 Mpixel/sec=400 kpixel/frame=640 pixels per line=480 
visible pixels per line.
So I usually record with 480 pixels x 576 lines, except for shows that I 
want on DVD.
Have you noted the setting for data rate ? That controls the amount of data, 
the number of pixels does not.
The more noisy signal you have, the higher should the data rate be.
I record at 4.5 Mbits/second=2 GB/hour. Then I transcode to MPEG4 at
1.4Mbits/second=
0.6 GB/hour. To fit a movie on a DVD, you might want to go to 4 
Mbits/second.
If you do not want to transcode, then it is easy to test different data 
rates via live tv.

Niels Dybdahl
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