Processing NTSC video feed for SPI display
Well you would need to digitize the video, extract luminance, chrominance &amp; sync information, downscale from 525 lines to 128 lines and output the data over SPI in real time. This sounds like a non-starter to me.

It would be easier to use the JPEG digital output from the camera and decompress this, since the resolution is compatible with the screen (160 X 120 vs. 160 X 128) although you still wouldn't get real-time video.