[mythtv-users] VGA -SCART and interlace (2x)

[Paul Gardiner]

John wrote:
> I've recently moved to trunk, to try the interlaced (2x) "de-interlacer".
> 
> I have a sony 100Hz CRT, and I'm playing back BBC 720x576 interlaced 
> over a VGA to SCART cable. my modeline is 720x576 interlaced. My video 
> card is an NVIDIA 6200. Quality on slow scenes is excellent, but I cant 
> see much if any improvement between using the interlaced (2x) and none. 
> Anybody else got this working ? Is there an arcane combination of "sync 
> on " settings that I need to use ?
> 
> 
> If it just doesn't work with NVIDIA cards, please reply, then I can stop 
> wasting my time !

What you should see is "none" works fine for a bit and then jumps into a
strange out-of-sync mode, where everything moving has combed ghosts. The
idea of Interlaced (2x) is to look identical to "none" but not go out of
sync.

The reason you're seeing no problem with "none" might be because the
program is actually progressive (although marked in the stream as
interlaced). I'm sure I've been seeing a lot of such content lately.
Best thing is to try "none" for an extended period to see if you ever
come across the out-of-sync mode. The News and sports programs still
seem to be interlaced. It's very noticable (well unbearable to watch).

Another possibility is that your TV can recognise the out-of-sync
interlace (when you are using none), and put it right (being a
100Hz set, it will have some sort of deinterlacing facility).

One other possibility is that you've run into the nVidia driver problem
with interlaced modes that has been mentioned here. I think that
would cause a halving of your vertical resolution. If that's the
case, the picture quality should be very much worse than watching
a program live on the TV without Myth.

Paul.