[mythtv-users] Modeline adjustments?
Cory Papenfuss
papenfuss at me.vt.edu
Tue Aug 8 12:12:26 UTC 2006
On Mon, 7 Aug 2006, Tim Scholl wrote:
> The final frontier! Have Myth running great I am now trying to transition
> to the HDTV display!
>
> I found a standard modeline of 1080i and put it into my XF86Config-4 config.
> ----------------
> HorizSync 31.5 - 37.9
> VertRefresh 59 - 61
>
> ModeLine "ATSC-1080-60i" 74.25 1920 1960 2016 2200 1080 1082 1088 1125
> Interlace
> ---------------
>
> I startup mythtv and the dispay looks good on my monitor!! sooooooooo...
> I attached the vga output to an Audio Authority A960 transcoder, turned on
> my HDTV, and got WALLA!! A fantastic picture, great color, stable, no
> jitter and looks great.
>
> Only one problem!!
>
> The left hand side of what should be the normal display, is in the middle
> of the screen!! Then rest of the display drops off at the end of the
> screen and wraps around to the other side and joins again in the middle.
> The full display is visable and clear as a bell!
>
You could try adjusting it to something more like this:
ModeLine "ATSC-1080-60i" 74.25 1920 2060 2116 2200 1080 1082 1088 1125
I added 100 dots of black on the right hand side and removed 100
dots of black on the left-hand side (i.e. changed 1960->2060 and
2016->2116). That should move the screen, but it won't move it anywhere
close to half a screen width.
> Since it looks good on the monitor, why is it so far off when displayed on
> the HDTV?
> Not being a that familer with modelines, is this a modeline issue or do I
> need to look elsewhere?
>
> Does anyone know what needs to be adjusted to get it to shifted to the left
> hand side?
>
You might try different combinations of [+-]hsync and [+-]vsync at
the end of the modeline:
ModeLine "ATSC-1080-60i" 74.25 1920 1960 2016 2200 1080 1082 1088 1125 +hysnc -vsync interlace
It definately sounds like the HDTV has having trouble finding the
sync pulse. Strictly speaking, HD-component requires bi-directional sync
signals, and that's a much harder thing to generate (correctly) from RGBHV
like VGA. I don't know if the A960 does that, or makes the easier
uni-directional sync. Any jumpers to twiddle on the transcoder?
-Cory
--
*************************************************************************
* Cory Papenfuss, Ph.D., PPSEL-IA *
* Electrical Engineering *
* Virginia Polytechnic Institute and State University *
*************************************************************************
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