[mythtv-users] 720x480 interlaced modeline for nvidia/svideo
jonese at zener.com
Fri Mar 10 16:50:05 UTC 2006
On 3/10/06, Robert Johnston <anaerin at gmail.com> wrote:
> On 3/10/06, Brian J. Murrell <brian at interlinx.bc.ca> wrote:
> <snip />
> I've got my PVR-250 feeding into my GeForce 5200, and watching CNN at
> the moment, there's no distortion on their ticker (When compared to a
> actual view on TV).
> Here's my XFree86Config-4:
> Section "Monitor"
> Identifier "Monitor0"
> Option "DPMS" "true"
> # HorizSync 28.0 - 78.0 # Warning: This may fry very old Monitors
> HorizSync 28.0 - 96.0 # Warning: This may fry old Monitors
> VertRefresh 50.0 - 75.0 # Very conservative. May flicker.
> # VertRefresh 50.0 - 62.0 # Extreme conservative. Will flicker.
> TFT default.
> DisplaySize 182 136
> ModeLine "720x480" 26.718 720 736 808 896 480 480 483 497 -Hsync +Vsync
> According to /proc/driver/nvidia/version I'm using:
> NVRM version: NVIDIA Linux x86 NVIDIA Kernel Module 1.0-7174 Tue Mar
> 22 06:44:39 PST 2005
> GCC version: gcc version 3.3.5 (Debian 1:3.3.5-12)
> And Myth 0.19 (SVN HEAD Rev 9261) has OpenGL VSync enabled (And is not
> using XvMC accelleration)
> So... you were saying...?
There are three things I look for ticker-line test (I use CNN).
1) Smooth flow. No jerking. (not a problem at present)
2) Jagged alternating scan lines. (a problem for me)
3) Full 720 pixel rendering. The scaler will throw away or insert
pixels to scale the image. You can see this by noticing "ripple" at a
fixed point in the scroll. Looks like the ticker is folder over
itself. There may be more than one pont.
What about your overscan setting? If I set it to "0" in the xorg.conf
file, my driver (7676) on a 5200 continues to scale the image
(reversed scale, the picture is shrunk) despite nvidia instructions
indicating "0" will disable the scaling (is this a bug?). I have to
push overscan setting to the max to get a picture that is the proper
I believe I'm using a correct modeline (I verified the timing values
against the proper NTSC timing values). The interlaced flag is
present (your line doesn't have it?)
Basically, I think if I could totally remove the overscan scaling that
is going on (despite setting it to "0"), I'd have a near perfect
picture (and I think others are having the same problem).
Maybe we are having driver-version issues here?
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