Hierarchical mode search with classification of bisectional prediction modes based on the position of motion boundary [video coding]

Video coding schemes, equipped with various kinds of prediction modes, improve coding efficiency by offering efficient prediction modes that adapt to the motion in a macroblock (MB). Operation time for motion estimation and mode selection, on the other hand, increases with the number of prediction modes. We have proposed a motion compensated prediction method (arbitrary-shape partitioning motion compensation: APMC) equipped with various inter prediction modes which adapts to the motion boundary of objects on an MB basis. This paper confirms the coding efficiency of APMC in comparison to the final specification of H.264/AVC and introduces a method to improve the computational performance of APMC by using a hierarchical mode search method based on motion boundary position within MBs. Simulation results show that APMC improves coding efficiency by about 5% in comparison with the final specification of H.264/AVC, and the proposed hierarchical mode search method decreases the operation time to about 60%, while maintaining the coding efficiency.