Research On Fast Motion Estimation Algorithm For Video Coding

Motion estimation(ME) is an important part of any video encoding system, Unfortunately,this feature usually requires a significant part of the encoding time. High-quality motion estimation algotithm is the premise and basis of highly efficient video code.So analyzing and studying quick motion estimation algorithm to improve the speed of coder code is very necessary.Motion estimation algotithm search the best matching point to obtain the motion vectoin in the search region using some one matching criterion.Different search methods use different search strategies to search the best matching point.Searching methods in common use has full search method, three-step search method,the new three-step search method,and diamond search method and so on.At present various search algorithms try to get best compromise between search rate and accuracy.The function of these algorithms all have room to improve in the specific video sequences.In this thesis,the main research and work include the following aspects:(1) First,introduction of the standards of H.264/AVC and encoder framework,the grade and level of H.264/AVC.Second,described the key technology of H.264/AVC, such as intra-prediction,interframe-prediction,integer transform,quantization,entropy coding,the hierarchical structure of algotithm,rate control,and filter.Finally,simple summary of the H.264/AVC standards.(2)Analyzing the full search method,three-step search method,the new three-step search method,cross-search method,the four-step search,diamond search method and the hexagonal search method,and conducting a simulation analysis of all algorithms.The simulation results confirm that the hexagon search algorithm has a relatively good search performance during the existing basic search algorithms.(3)On the base of hexagonal algorithm to push forward improved hexagonal algorithm.The improved hexagonal search algorithm use horizontal and vertical template instead of the fixed horizontal template.This paper presents an improved hexagonal search algorithm uses different search templates to carry on motion estimation through predicting the motion types of the macro-block.When the block is quick,we use adaptive hexagonal template,if not,we use SDSP template.Comparing with the hexagonal algorithm,the experiment shows that,the search algorithm in the search of the majority of sports video sequences,especially the direction of movement in the vertical macroblock dramatic,reduce search point,has improved encod speed to search for accuracy at the same time.