I'm capturing the HDMI out from a Panasonic GH2 camera, and trying to fix a flaw in the signal. The (yuv) channels are slightly shifted so saturated objects have a nasty interlaced fringe around them.
The basic idea:
Start with full rez (not subsampled) chroma
Shift each YUV channel by a half-pixel in certain directions
Convert to subsampled chroma format
I'm trying to port it to MAX but I'm coming up short.
Jitter cpu objects like jit.rota won't do subpixel positioning. It seems (from the forums) that there's no way to unpack channels on the GPU without either shader programming or MAX6/gen.