Rate optimization by true motion estimation

We propose a rate-optimized motion estimation based on a "true" motion tracker. We observe that the piecewise continuous motion field reduces the bit rate for differentially encoded motion vectors. Hence, a neighborhood relaxation method is proposed. In addition, in current MPEG-4 video VM, each video-object-plane (VOP) is individually coded by a block-based approach. The bit rate can be further improved by the removal of redundancy among the block motion vectors within the same VOP. Therefore, we also propose an object-and-block hybrid coding.