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The joys of nvidia TV out

Posted 11-18-2006 at 11:12 PM by Caysho

I've been playing with MythTV (specifically KnoppMythR5D1), and I'm slowing discovering that not all tv out's were made the same.

The plan - to have twinview running in clone mode. I wanted to have the display to go to the tv, but to have the option to plug a monitor in for troubleshooting purposes. Initially I was trying with the ASUS V7100PRO/64M (it's a Geforce 4 MX/MX400 , if I recall correctly). It has a Brooktree 869 TV chip on it (Conexant Bt869KRF).


The result - frustration.
My first attempt was actually nearly correct, but I got this on the tv:
In all the examples I had looked at, 800x600 was always emphasised.

My second attempt was to simply get the TV out on its own happening.
Again, with 800x600. At this point I also played around with the horizontal and vertical refreshes/sync's, but still no luck.

My third attempt, as above, except with 640x480:
At last, it works. I also tried 720x576 (PAL), and that was also ok. Here's a clearer image:

Now that I had that sorted, I modified the config with the twinview settings to use 640x480, and I got it happening on both screens. At this point I thought I was sorted, but then I noticed something odd - the TV display had the X desktop, but the mythTV frontend was too large. If I changed the resolution that the monitor ran at to 1024x786, the TV display was zoomed in. At 640x480, the front end was shifted to the top left of the TV; the front end's top left would have been about another foot up/left.
The entire screen was being used, so I assumed that it must be possible to make use of the screen with no underscan, plus have MythTV looking normal. Unfortunately, the overscan option made no difference, and I couldn't get the frontend to "shrink" enough to display optimally.

If this sounds confusing, it's because I was getting some odd effects and I can't recall which exact settings caused them.
It appears something strange happens with the virtual resolution (?).

After all that, I thought I'd give my other card a try - GeForce FX5700 256MB VIVO.
TwinView was about the same, but TV out on its own was better:
The black border (all four sides) is less than the v7100pro's, so I think I'll be sticking with this as just a tv out setup.

These were my references:

I tried nvtv to do things with the overscan, but it segfaults with this KnoppMyth release.

Using R5F1,
A section from
I have nvidia-settings set to Overscan 13, and within MythTV, the horizontal overscan is set to -10. Aspect ratio is 16:9 Zoom.

Section "Device"
Option "TwinView" "true"
Option "ConnectedMonitor" "crt,tv"
Option "TwinViewOrientation" "Clone"
Option "SecondMonitorHorizSync" "30-50"
Option "SecondMonitorVertRefresh" "60"
Option "MetaModes" "800x600,800x600; 640x480,640x480"
Option "TVStandard" "PAL-B"
Option "TVOutFormat" "SVIDEO"
Option "RenderAccel" "true"

I can hookup a normal LCD screen via VGA and use it in TwinView configuration.
The LCD display is distorted due to running full screen (5:4 or 4:3).
The MythTV screen borders are slightly outside the viewable area, but viewing TV is fine.
Unfortunately, this Xorg configuration causes xorg to run at ~85%.
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    Posted 12-31-1969 at 07:00 PM by Caysho Caysho is offline


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