Efficient Coding of Motion Vector Predictor Using Phased-in Code

Abstract

The H.264/AVC video coding standard performs inter prediction using variable block sizes to improve coding efficiency. Since we predict the motion in the homogeneous region as well as in the non-homogeneous region accurately using variable block sizes, we can reduce residual data effectively. However, each motion vector should be transmitted to the decoder. In low bit rate environments, the motion vector information takes approximately 40% of the total bitstream. Thus, motion vector competition was proposed to reduce the amount of motion information. Since the size of the motion vector difference is reduced by motion vector competition, it requires only a small number of bits for motion vector information. However, we need to send the corresponding index of the best motion vector predictor to the decoder. In this paper, we propose a new codeword table based on the phased-in code to encode the index of the motion vector predictor efficiently. Experimental results show that the proposed algorithm reduces the average bit rate by 7.24% for similar PSNR values, and it improves the average image quality by 0.36dB at similar bit rates.