Graphics 7800gt PCI-Express Svideo input issue

I have 2 7800gt's run in sli, both cards are capable of video capture via the nvidia driver. here is the problem i have run into. the first card will show video captured via svideo or composite but only in black and white. occasionally i get colored bars that pass through the video. the second card just shows black for everything and doesn't seem to be working. i have tried these cards in 2 different machines, in different configurations (swapping them around, only one in at a time,...) and have had no success. any ideas from anyone?

Thanks