I'm trying to simulate a Sky box by providing the Myth box with some kind of svideo input to it.

I have tried two things so far. I set up another computer with a TV-out to output a desktop at what I presume is 640x480. My monitor can display this without issue, but I just can't seem to get the Myth box to show it.

The second thing I tried is a camera with a composite out which shows a slideshow of the stored photos. This works on input 0, though I have not worked out how to get colour always yet.

Does anybody have any tips for how I might get the other computer (with a Nvidia card) to output a signal that is accepted as valid by the TV card input?

The TV card is a Hauppauge PVR 350.