Darren Wilkinson wrote:
Recent Nvidia cards haven't been a good choice for softdevice. IIRC it's because nvidia dropped some overlay features in the last few years. When I was trying to get softdevice to work with directfb on my geforce 6600 I had to alter the alphablend (like you've been told), the stretchblit and the pixelformat settings. I can't remember what they changed to though.
http://www.spinics.net/lists/vdr/msg13392.html
Select YUY2 as the pixel format and select Use StrectBlit. You'll now get video.