[mythtv-users] NTSC ModeLine

Shaun Jackman sjackman at gmail.com
Thu Sep 2 19:11:57 EDT 2004

I've having a lot of trouble getting TV out to work with my G550. From
what I understand, the G400 had hardware to scale down whatever
resolution you were using to NTSC. The G550 doesn't include this
hardware, so the precise TV resolution must be used. I think 640x480
should be good, but I wasn't sure if it should be normal 640x480 at 60p
or interlaced, or NTSC, or what. So, I'm trying all of them. You're
right though. It's time to get on with life.  ; )


On Thu, 2 Sep 2004 18:21:15 -0400 (EDT), Cory Papenfuss
<papenfuss at juneau.me.vt.edu> wrote:
>         I wrote awhile back about modelines... check the archives and the wiki.
> In short, here's what I use, and it produces precisely NTSC spec (or at least
> the SDTV that I use thinks so)
> Modeline     "coryntsci"  14.318 720 760 824 910 480 484 492 525 interlace
>         I always hated that error message in X, because there's a big
> difference between a bad mode due to "clock" or "interlace" or "doublescan".
> You're using a Matrox card (MGA), and my experience has always been excellent
> with linux, custom modelines, interlaced, sync-on-green, and all sorts of
> nasties I could throw at it.
>         Check elsewhere in the logs for a "Dotclock range 12.0-250Mhz" to rule
> out that.  Try a standard VESA interlace modeline (e.g. 1024x768 at 43) to see if
> the card doesn't do interlace... some don't.
>         Of course, the obligatory question... why are you doing this?  Do you
> have a component tv that only does 480i or something?  VGA monitors don't do
> NTSC, but they will do double.  If you're using a standard tvout card, double
> the frequency, remove the interlace, and get on with life.  :)
> -Cory

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