Vertical bands in capturing & viewing Satellite TV

[Serville]

I'm a complete novice in capturing, so bear with me.

I tried to record a satellite TV program from my TV's Monitor Out to my Winfast TV TUner 2000/XP. But there is one annoying picture problem which always occurs regardless the program I use (Winfast PVR, WinDVR). There are always vertical bands of the same type all over the picture. These bands are visible in the computer screen and in the capture. What are these bands ? I know this must be caused by some compatibilites between TV & computer system. How can I remove them ?

A sample image is included.

[mikiem]

Have you tried s-vid cable from sat box rather then TV?
Might try capture with V/Dub using filtering?

[jagabo]

You have a ground loop problem.

http://www.elect-spec.com/faqgrdl.htm

[Serville]

You have a ground loop problem.

http://www.elect-spec.com/faqgrdl.htm

Sorry for late reply. Yes, after reading the above page, I really think it is a ground loop problem, or even perhaps some signal interference caused by inductive pickup in the cable. My brother's friend who understands electrical stuffs also suspected the same. Now, I have at least a basis for troubleshooting. I will try to change some cable and do some experiments with the tv box & computer to see if it helps.

Thank you for your advice.

[Serville]

Update on this old thread.....

These vertical bars are visible with Winfast PVR and WinDVR, but are not visible with DScaler. If this is a ground-loop, shouldn't Dscaler have the problem too ?
Does DScaler have filters or anything ?

But I found another strange thing today. The vertical bar in Winfast PVR/WinDVR WILL disappear IF I run Dscaler first and quit. But as soon as I reboot, the vertical bars come back unless I run Dscaler first before PVR.
Why is this ? Does Dscaler leave something or activate something in the memory that makes Winfast PVR/WinDVR filter the ground-loop problem ?

Now I wonder whether this is actually a ground-loop or a software problem. I've changed drivers/anything I can think of, but the problem persists. Someone has any idea why this is happening ?

[jagabo]

Maybe there is a problem with the way the driver for your graphics card is scaling the video for the screen. Try opening one of your captures with VirutualDubMod. It doesn't use DirectShow overlays to display the video. Do you see the vertical lines there?

[Serville]

yes it shows even in Virtualdub