poor quality using geforce4 s video tv out

[lichen86]

I recently hooked up my box to my TV via the s-video out on the video card. I using a fairly long (50 ft) s-video cable, and I get a perfect picture on my TV. However, whenever I try to play a DVD or any full screen video through Windows Media Player, I get strange scan lines and overall very poor quality. As long as I'm not using "full screen" in WMP, the picture is crystal clear. Anyone have any ideas about what might be causing this?? I doubt its the cable because of the clear connection except during full screen. Here are my system specs:
-Athlon XP 2000
-512 PC2700 Crucial
-ASUS a7n8x Nforce2
-Gainward Geforce4 TI 4200 128MB w/tv out
-Sound Blaster Live Platinum

 

[dakota81]

Some friends of mine have a similar situation and their problem is interference in the wires. When the desktop is up, the picture is brighter, hence more voltage traving along the S-Video cable, thus less of an impact due to interference.

And maybe it's the case where what you're calling "scan lines" isn't what I'm calling "scan lines"...