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Old 03-06-07, 07:07 PM   #1
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Join Date: Oct 2005
Posts: 10
Default Bad S-Video signal - luminance is really composite?!


I have a problem using the S-Video TV-out signal in PAL modes. When connecting the S-Video output to an S-Video input on the television it will not properly detect the S-Video signal, but only display a composite signal. The result is much worse picture quality. I use the following settings:
Option "TVStandard" "PAL-B"
Option "TVOutFormat" "SVIDEO"

Experiments with disconnecting the chrominance signal (C) show that the luminance signal (Y) still carries color information - and therefore really is a composite signal! The television detects this (a Sony set) and runs in composite mode. Only once in a while the television picks up the real S-Video signal and displays with a much better picture quality!

When running in NTSC mode the television properly detect the S-Video signal with a much better picture quality as a result. In NTSC the picture also turns black and white when the chrominance (C) signal is disconnected - as it should. But NTSC is not an acceptable option for displaying recorded PAL television shows...

My board is a Asus A8N-VM CSM (GeForce 6150) with the TV-Out bracket. I am running Ubuntu Feisty and NVidia drivers 9631. The problem is quite similar when running Win2000 and 9131 drivers. My Video BIOS is

Is there any way to remove the chrominance information from the luminance (Y) signal and get a proper S-Video signal??
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