Abstract: Some modifications are made on the present algorithm for motion vector coding. In the new algorithm, motion vector coding is divided into three modes according to the difference between horizontal movement and vertical movement. For different coding modes, different variable length code (VLC) tables are used. The simulation results show that the new algorithm reduces 10%~40% bits for motion vector coding and improves the quality of reconstructed image by 0. 05~0. 1dB. In addition, the new method improves the robustness of video bit stream against channel errors and makes the rate controlling operation of video encoders more accurate.

Key words: MPEG-4, PFGS, streaming video, networking video, motion estimation and compensation