This is a rough effect that mimics the look of a grab from a BetacamSP. It reduces the horisontal resolution of the two chroma channels and adds dot-crawl in the luma channel.

Useful when you are trying to composite CG elements on such a grab.
Icon is for alternate icon set in Shake 2.30 and higher.

note: There is no color correction in this macro, except for the RGB to YUV conversion (lossy).