Research And Implementation Of Intra Fast Mode Selection Algorithm Based On H.264

The H.264/AVC standard has the advantages of good error resistance and high coding efficiency.However,the excellent characteristics of H.264/AVC are limited by the huge amount of computation,which limits the practical application.Intra prediction is one of the key technologies of H.264/AVC.The best prediction mode is selected by traversing the search by the full search algorithm.The algorithm can achieve the highest accuracy,but it requires 4X(16X9+4)= 592 generations of value calculation.Greatly increasing the coding complexity.Aiming at the high complexity of H.264/AVC full search algorithm,this paper proposes a fast mode selection algorithm,which reduces the coding complexity of intra prediction.Firstly,the coding framework of H.264/AVC is expounded,and the intra prediction technology is introduced.Then,the full-search algorithm used in the traditional intra prediction technology is simulated,and the complexity and optimization aspects of the algorithm are analyzed.Then based on the low complexity requirements,the fast mode selection algorithm of this paper is proposed.The Intra4X4 and Intra16X16 modes are pre-judgated by the MAD threshold method,and some prediction modes are eliminated,which reduces the number of searches.The algorithm splits the original MAD formula,and the optimized MAD formula can further obtain the smoothness of the 4X4 sub-block,which improves the macroblock threshold estimation accuracy.At the same time,the search frequency of the Intra4X4 mode is further reduced according to the frequency characteristics of the prediction mode.The algorithm complexity is greatly reduced.Finally,under the JM8.6 coding model platform,three video sequences are selected as test samples,and the full search algorithm and fast mode selection algorithm are simulated and compared.It can be seen from the experimental conclusion that the optimized algorithm has an average signal-to-noise ratio reduction of only 0.23%,a code rate increase of about 2.64%,and a coding time of about 35.04%.In the case that the picture quality and the code rate do not change much,the coding time is greatly reduced,so the improved algorithm is effective in reducing the complexity of the intra prediction coding.At the same time,based on the hardware resources of iTOP-4412 development board,this paper builds a Linux software development environment.Under the software and hardware platform,a video coding system is designed based on the optimization algorithm proposed in this paper,which reduces the complexity of video coding.