[mythtv-users] Any hope for 1080i content at 1080i with nVidia?

[Tom Dexter]

>From: "Steve Smith" Date: Mon, 30 Jul 2007 12:32:00 +0100
>
>
>Never mind 1080i what about 576i (ignoring TVOUT chips which seem basically
>broken in this respect) ?!?!
>
>It seems the simple problem is that FRAME sync (rather than FIELD sync) 
>just
>isn't working
>somewhere along the line...
>
>We shouldn't need to deinterlace if we have an interlaced display (capable
>of the relevant resolution) available, full stop, period, end of story.
>
>The fact that we do means that the syncing system is not working
>somewhere along the line, maybe it's the card, maybe the nvidia driver,
>maybe Myth ... does anyone know?
>
>Regarding bob deinterlace and "too small a refresh rate". There was a patch
>posted on the list a few weeks ago by a guy called Viktor. Works well.
>
>Cheers
>
>Steve

The whole issue with getting bob deinterlacing working by adjusting the 
refresh rate got me wondering...I couldn't remember why I wasn't using it 
with my original 1080i mode.  Then I remembered that, for one thing, it 
always gave me that error, and for another, I read in a number of places 
that you simply shouldn't use bob with an interlaced display.

Out of curiosity, I tried that patch of Viktor's you mentioned (which is 
here for anyone interested):

http://svn.mythtv.org/trac/ticket/2903

I'm in the U.S. by the way...from your posts and his I see you're dealing 
with PAL frame rates.  I'm running Gentoo and didn't feel like making a 
custom ebuild just yet, so I simply installed manually using the Gentoo 
ebuild command editing in that code change between the unpack and compile 
steps.  The patch seemed to work just fine.  Instead of disallowing bob 
because the refresh rate was being reported at 33333, the refresh rate was 
reported as 16666, and bob worked just fine, and does look noticeable better 
than kerneldint.

While I'm sure there are good reasons the devs didn't want to incorporate 
the patch, one comment they made on Viktor's bug report confuses me:

"You also don't want to use bob-deint with an interlaced display, use kernel 
or linear blend when there is a resolution missmatch and no deinterlacing 
when the source and destination line count matches.

See mythtv-vid branch for configuring such a setup."

What do they mean by that last statement?  Isn't deinterlacing always 
disabled automatically when you view non-interlaced content?  I'm running 
0.20.1 (svn 13344).  Whenever I watch livetv or recording from stations such 
as Fox or ABC, who broadcast in 720p, my logs (assuming I'm using -v 
playback) show something like:

2007-07-30 14:25:58.936 Disabled deinterlacing

What are they talking about there?  I don't understand that reference to the 
mythtv-vid branch.

Tom

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