A fast motion estimation method for MPEG-4 arbitrarily shaped objects

This paper presents an efficient motion estimation method for an arbitrarily shaped video object which significantly reduces the number of searches in motion estimation for shape and texture coding in MPEG-4. The proposed method can be employed in an MPEG-4 encoder with other fast search schemes. By examining the content of the alpha plane, a mask for the effective search area can be generated. With the knowledge of the mask, the proposed method disregards part of the reference VOP that is completely outside an object and hence reduces the number of searches significantly for both motion estimation processes in shape and texture coding compared to the full search method while providing an identical search results.