[mythtv-users] interlace issue on TV?

[Paul Gardiner]

Udo van den Heuvel wrote:
> Hello,
> 
> As you know I record SD TV signals from the Digitenne network here in 
> the Netherlands.
> I play them back on my VIA EN12000 via composite video to my Philips CRT 
> TV using "720x576Over" since the NoScale mode is not available for the 
> VT1625 encoder on this board.
> 
> The recordings look OK except that there's something 'jumpy' about the 
> movements on the TV screen. They do not appear so smooth. As if 
> deinterlacing goes wrong.
> On the PC monitor, though, all is fine.
> 
> I set mythfrontend to use VIA XvMC as decoder and xvmc-blit as renderer, 
> chromakey osd. I chose 'none' for both deinterlacer settings on the next 
> page. No filtering is used.
> 
> Does this mean that nothing is done to the video stream before it is 
> displayed?
> 
> If so, what is causing the jumpy movements?

Two possibilities. If moving objects have a ripply edge, and
the problem is always present, then you may be scaling the
video. It is ok to scale the menus, but then you must uncheck
the box that says something like "use the same scaling for
the video as the menu".

If the problem is more like the video jumping 3 steps
forward and 1 back repeatedly, and the problem isn't
always present then it's probably the interlaced display
being out of sync with the video (when it happens, you
should be able to pause and unpause a few times to cure it).
There's a better cure: see http://svn.mythtv.org/trac/ticket/6391.
With openchrome drivers, you may find you don't need the
patch from Ticket #2903 to make the fieldorder deinterlacer work.

With my VT1625 based board, I found mode 720x576 better than 
720x576Over. Also I've had better results from a VT1622A based
board.

Also, make sure you have TvDeflicker set to 0 in xorg.conf.

Cheers,
	Paul.