Bidirectional Motion Estimation Algorithm for B Picture in H.264/AVC

Abstract-Bidirectional motion estimation is one of the important features of B picture coding in H.264/AVC. This paper discusses the procedure of bidirectional integer pixel motion search and fractional pixel motion search. Integer motion search is to get the integer bidirectional motion vectors based on four times iterations. Fractional motion search should be executed twice to refine the two pairs of bi-directional motion vectors to quarter precision. Computer simulation results demonstrate that with this technique the prediction error in some scenes is significantly reduced. Joint estimation of forward and backward motion vectors used in the bi-predictive pictures (B pictures) can efficiently improve the coding performance of  B pictures.