H.264 Motion Estimation Technology Research And Improvement

H.264 is a video coding standard jointly developed by ITU-T SG16 Q.6 Video Coding Experts Group and ISO/IEC Moving Picture Experts Group. This coding standard has high coding efficiency by intrucding some new features including motion estimation, which dedicates to reduce the bit rate and the occupation of bindwith by searching the most similar block in the reference frames.The high accuracy fractional-pel motion estimation and the multi-reference frames make the H.264 having extreme coding complexity. In order to reduce the searching complexity, the standard uses some search algorithms based on MV predication subsets, the two algorithms have rapidity improve search efficiency compared to some fast search algorithms which only focus on search mode .This paper first discusses the basic principles and key technologies of H.264 video coding standard, then in depth analyses the H.264 recommended core algorithm of motion estimation EPZS. The EPZS can achieve a good performance if the video sequence only has low motion and no sudden motion, however when the sequence having charp change and accelerated motion there will be some influence on the performance. This paper does some improve on EPZS to reduce the motion estimation time of various video sequence and maintain the image quality .EPZS will calculate all the remain three predicted subsets, if the subset S1 does't satisfy the termination condition, the improved EPZS algorithm of this paper just check the subsets of S2 and S3, only when they all don't meet the temiantion condition then examines the subset S4. This improvement can reduce the unnecessary calculation for the smooth picture. At last the improved EPZS algorithm also selects the subset S4 member for incressing the chance of searching the optimal MV.