1. A method of preprocessing for motion-compensated video encoding, comprising: (a) providing a frame in a video sequence for motion-compensated encoding; (b) for a pixel in said frame, comparing a difference between (i) the value of said pixel and (ii) the predicted value of said pixel from motion compensation prediction of said frame to a first level; (c) when said comparing of step (b) indicates said difference is greater than said first level, apply lowpass filtering to said pixel; and (d) repeating steps (b)-(c) for other pixels of said frame; (e) motion-compensated encoding of said frame after said filtering.