[mythtv-users] Stupid question - deinterlacing

Goga goga777 at front.ru
Sun Feb 22 19:10:37 UTC 2009


> >> Perhaps this is a stupid question. I have a 1080p plasma panel and
> >> watching the OTA 1080i signal, the picture looks real good. So to me,
> >> that would infer that the TV has a good quality de-interlacer built
> >> in. I don't know if it is possible, but could mythtv switch the video
> >> signal of the graphics card to match the OTA stream and leave it to
> >> the TV to perform the work in making the picture look as good as it
> >> can on the display?
> >
> > I tried that.
> >
> > I set my Sony Bravia TV to 1080i and fed it 1080i signal via MythTV
> > after turning off all deinterlacer ; result:  it looked crap
> >
> > Like no deinterlacing happened at all.
> >
> > Some people commented that there was an issue with nvidia cards not
> > outputting an interlaced signal properly ...
> >
> > Jean-Yves
> 
> Yup...anyone with a 1080i native display (like my Hitachi RPCRT) can
> tell you that it's impossible with the Linux nVidia drivers (newer
> than some ancient version...8183 I think) to get correct 1080i output
> of 1080i content without enabling deinterlacing in MythTV.  A common
> symptom on a 1080i display is that it might look great for 10 or 15
> seconds and then drift out of sync causing unspeakable motion blur.
> 
> Since proper 1080i would surely work on a 1080i native display, that
> tells me they're doing something very wrong...something that would
> surely screw up a 1080p TVs deinterlacer.

yes. you are right -  nvidia cards (and ati too) can't work properly with interlaced video 
there's project about that issue, but only for ATI Radeon cards
http://lowbyte.de/vga-sync-fields/vga-sync-fields-0.0.10/README
========================================================================
This is a patch collection with some additional tools allowing you to 
synchronize VGA video timing to an external signal source. This way 
you may overcome common problems on today's PC VGA compatible hardware
when being used as frontend for live TV.

You can interface softdecoders like xine or softdevice to 
Klaus Schmidinger's VDR (http://www.cadsoft.de/vdr/). With SCART
output quality equaling a fullfeatured (firmware-based decoder) card.

Now cheap standard PC hardware with low processor power and a budget card
(without decoder) is sufficient to build a low-cost high-quality SCART-output
video disk recorder under linux.

Some more information about the project is available at

http://www.spinics.net/lists/vdr/msg17317.html
and
http://www.vdr-portal.de/board/thread.php?threadid=78480

The area down from here to the end of the document is merely some kind
of scratch pad. As time permits things will be reorganized for better
reading
========================================================================

also you can have a look on that discussion 

 vdpau output to pal tv
http://www.linuxtv.org/pipermail/vdr/2009-February/019605.html



Goga


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