.h.264/avc Interframe Coding Algorithm Study

H.264/AVC is the newest standard approved by the ITU-T and ISO organizations, which represents a number of advances in video coding technology and becomes the newest international video coding standard because of both high coding efficiency and network friendliness. The main goals of this standardization are to develop a simple and straightforward video coding design with enhanced compression performance. Compared to MPEG-4 advanced simple profile, up to 50% of bit-rate reduction can be achieved.Some new techniques, such as spatial prediction in intra coding, adaptive block size motion compensation with small block sizes, Quarter-pel accurate motion compensation, 4×4 integer transformation, multiples reference pictures prediction and context adaptive binary arithmetic coding (CABAC), are used in this standard. With the use of these techniques, both compression efficiency and encoding quality are greatly improved.This new features of H.264/AVC increase not only the complexity of coding basic modules, but also the one of algorithms by times. That makes it very difficult for practical applications such as in real time video communication application or in some embedded system. So major works are as follows:Firstly, because motion estimation needs the most complexity of computations, a novel fast motion estimation algorithm called Motion Vector Prediction and Mode Adaptive Search is proposed in the paper. According to center-bias property and spatial-temporal correlation of the motion vector field, the type of local motion activity is first determined. Based on the decision, different search strategies are adaptively utilized; The initial Search center is predicted by the motion vector of its neighboring macroblocks. Stop criteria is introduced to detect the most possibly candidate macoblock, thus terminating current search immediately. Three novel search strategies are adopted, including the Similar-Small Diamond Search for the macroblock with low motion activity, the Hexagon Search for the macroblock with middle motion, and the Square-Hexagon Search for the macroblock with large motion. Experimental results show that the proposed algorithm provides faster speed and higher precision than most existing fast block-matching algorithm.Secondly, adaptive block size motion compensation with small block size based on RDO is the other side which needs a lot of computation, an improved residual texture based fast block size selection algorithm is proposed. First, SKIP mode is determined, and determined the intra modes through spatial-temporal relations. Experimental results show that the proposed algorithm has decrease the computations and make sure the coding efficiency and quality.