MOTION ESTIMATION AND BLOCK MATCHING PATTERN

A motion estimation process improves coding efficiency by using a modified search criteria. The modified search criteria takes into account the error signal needed to encode a block of pixels as well as the the motion data when selecting a matching block in a target frame. This approach reduces the combined overhead of both the motion and error signal data for the encoded block of pixels. When used in conjunction with a spiral search path in the target frame, the modified search criteria improves the speed of the search because it eliminates the need for an exhaustive search. A predicted motion vector is used to optimize the search location. Preferably the search order is selected so that target pixels closer to predicted point are searched before pixels farther away in the target frame.