Research On The Intra And Inter Prediction In H.264

ITU-T H.264/MPEG-4 Part 10 Advanced Video Coding (commonly referred as H.264/AVC) is the newest international video coding standard. It was developed by the Joint Video Team (JVT) consisting of experts from ITU-T's Video Coding Experts Group (VCEG) and Moving Picture Experts Group (MPEG). The standard improves compression efficiency by a factor about two (on average) over H.263. Several coding elements contribute to the great improvement in compression efficiency of the new standard. However, the computational complexity of the H.264/AVC encoder is dramatically increased because of its optimization technique, and is about three times of H.263's. Then it is necessary to optimize its algorithms for the implement in real-time applications.The basic theories for video encoding and the development of video encoding standard are introduced in Chapter 1, and the main content of H.264 is introduced in Chapter 2.The paper achieves the optimization of intra-prediction and mode selection in H.264, which is introduced in Chapter 3 and 4. The study result is showed as follow:1. Based on the rule that whether the 4x4 block's residual coefficients after transforming and quantification equal to zero or not, get a threshold which can quit the process of the prediction mode selection ahead and a fast prediction mode selection which is based on threshold is proposed. The threshold can be adjusted with the QP value.2. The intra-prediction method is analyzed deeply. Based on the comparability of the coding block and the relativity between the optimal prediction mode and the suboptimal prediction mode, a fast prediction-mode- selection arithmetic is proposed. The algorithm checks the SAD of the most possible prediction mode and its two side prediction modes to find a search direction firstly. Then repeat the operation until finding the optimal prediction mode. The method reduces the complexity of intra prediction.3. The Diamond-Search algorithm can search the optimal matching point by shifting the search window. But because of its fixed templates and its search directions, it searches a lot of redundant points. Aiming at solving the problem, a fast motion-estimation algorithm is proposed by analyzing the inter-motion-estimation method. Based on the characteristic of DS and the motion-direction prediction, the algorithm introduces a project of search direction extendable and a threshold is provided to improve the search speed.