Image preprocessing with selective lowpass filtering from motion compensation

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;
• (d) for said pixel, comparing said difference to a second level which is less than said first level;
• (e) when said comparing of step (d) indicates said difference is greater than said second level but less than or equal to said first level, comparing the magnitude of the motion vector for the block containing said pixel to a first threshold;
• (f) when said comparing of step (e) indicates the magnitude of said motion vector is greater than said first threshold, spatial lowpass filtering to said pixel;
• (g) repeating steps (b)-(f) for other pixels of said frame:
• (h) motion-compensated encoding of said frame after said filtering:
• (i) wherein said filtering of step (c) is both spatial in said frame and temporal over other frames of said video sequence.