I am trying to output NTSC SD video with the ADV7391. I have been writing the BT656 data stream to it with a test pattern I generated myself, but so far, all I get is a black screen. On a scope I can see the syncs coming out with the color burst, but the video is flat lined black. Any ideas? I have not implemented the SDA/SCL interface, and I hope I can just start outputing video in the default mode.