Multi-Hypothesis Prediction Based on Implicit Motion Vector Derivation for Video Coding

Traditional video coding standards H.264/AVC and HEVC adopt inter-frame prediction with single prediction (P frame) and bi-directional prediction (B frame), in which one and two hypotheses are utilized to generate the final prediction. Though more hypotheses have been proved to significantly improve the prediction accuracy, the additional bits used for signaling the motion information may decrease the overall rate-distortion performance conversely. In this paper, we propose a multi-hypothesis prediction scheme based on implicit derivation of motion vector. In the proposed scheme, the first prediction block is generated identically with the method in HEVC. Subsequently, motion estimation is applied on each reference frame by taking the first prediction block as template, and the search results serve as the additional hypothesis candidates. In this manner, the overheads of motion vector can be reduced. Simulation results show that the proposed algorithm can achieve average 1.1% coding gain compared to HEVC.