[mythtv-users] Struggling with Xwindows DVI to HDTV 1080i

Steve Adeff adeffs at gmail.com
Wed Dec 28 01:20:17 EST 2005

On Tuesday 27 December 2005 18:38, Len Reed wrote:
> I've got an nvidia 6200 with DVI out connected to my Mitsubishi HDTV
> (DVIS to HDMI cable).  The TV does 720p and 1080i on HDMI: it's worked
> from both the cable box and from a DVD player that does upscaling.
> I can get the TV to recognize that it's getting 1080i input from the
> computer.  (The info on the screen says so.)  I can't get it to deal
> with 720p for some reason.  I can get the TV to handle lower resolution
> SVGA and XGA modes up to 1024x768 fine.
> With 1080i I get what is close to the twm screen, but there are two
> problems:
> 1. The screen is greatly overscanned.  Perhaps 20% is not displayed.
> 2. The interlacing is off, or at least that's my guess.  Everything is
> displayed twice, with one flickering image directly below another.  They
> are close: the bar at the top of an xterm has its two images overlapping.
> I've tried every modeline I can find, and have tried two different
> modeline calculators, but I can't get the two images to converge.  The
> TV seems to be reporting things correctly to X (59-61 Vsync, reasonable
> Hsync, etc.)  Telling X to ignore the TV's info doesn't help in any case.
> It seems like it should be easy enough to play with the vertical
> blanking interval to fix this, and that I'm close.  But I'm guessing,
> and I'm not making progress.  Is there a reasonble way to tweak the
> modeline to iterate toward a solution here?
> Details:
> Fedora core 4, x86_64
> Athlon-64x2 (3800+)
> ndvidia 6200 card
> latest nvidia X driver, compiled on the machine
> Thanks,
> Len

newer nvidia drivers don't support interlace modes over DVI.

Overscan won't change what you see for TV (ie. the overscan is the same 
whether from your computer or your cablebox), so change the gui overscan 
settings for your TV to fix the gui. if you want to fix tv video, SVN lets 
you adjust overscan, or find the service menu info for your tv to lessen its 


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