[mythtv-users] Resolution for PAL analgue TV
mythtv at mctubster.com
Mon Dec 13 09:07:00 UTC 2004
Phill Edwards wrote:
>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
>systems. Also, I thought I should also set the X "modes" and "metamodes"
>settings to 720x576 but it doesn't allow this. Am I trying to do something
Phil. Is your capture card hardware based encoding or software?
In my case I have a PVR350 (h/w based) + DVB card. Both are set to
record at 720x576 in Myth Setup.
The capture resolution should reflect your source resolution ..... ie
there is no point capturing at 720x576 if you have a 4:3 analogue
stream. 640x480 (4:3) is more than enough.
If you are capturing an analogue output (but digital broadcast) stream
such as Sky, (Foxtel?) then you want a higher resolution. Generally
these broadcasts are widescreen, so you want as much vertical resolution
as you can get, since most of them are letterboxed anyway. 720x576 only
gives 5:4 aspect, whereas most shows are 16:9 or movies even worse
My settings are
1 / The DVB card ignores this setting (it doesn't have a choice about
the resolution, as Myth just saves the mpg2 stream
2004-12-12 20:01:53 DVB#0 Recorder: Card opened successfully.
Videostream: ASPECT: 16:9 Size = 704x576 FRate: 25 fps BRate: 15.00
Audiostream: Layer: 1 BRate: 128 kb/s Freq: 0.0 kHz
2 / More interestingly (for me at least) is that I tried to get an
display compatible modeline out of my TNT2 card, to drive a 1280x720
projector. In the end I gave up and feed it 800x600, which gives me the
correct aspect ratio. I assume that Myth on playback is scaling the
720x576 to 800x600, and then the projector is scaling it to 1280x720 to
display. It looks fine, but not for a purist to consider
Hope something helps!
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