Research And Improvement Of Intra Prediction Algorithm In H.264

With the rapid development of computer networks and streaming media technology, The video compression technology has been a great deal of attention, and a variety of video standards play an increasingly important role in our life. H.264video coding standard is the most popular international standard, adding a lot of new technology on the basis of the original H Series, and it is these new technology makes it very good coding, but also greatly increase coding complexity, so that the standards can not be applied in the real-time requirements of occasions. Therefore, how to reduce the coding complexity has become one of our important research content.As one of the key technologies of the H.264standard-intra prediction, intra prediction is account for a large proportion of H.264encoding process and therefore reduce the intra prediction coding complexity, can reduce the overall H.264encoding complexity, at the same time has also become the focus of our research content.Of course, we must first know the original intra prediction algorithm in H.264video coding standard, before they can be improved. In the H.264video coding standard, the original intra prediction algorithm, we have to consider selecting the brightness4×4block prediction or16×16brightness of the blocks to predict the9prediction mode of the former and the latter’s four kinds of prediction modes need to calculate, the number of calculations148times, and finally to the chroma macroblock outer loop, To calculate the total number up to592, plus the calculated once the process is relatively cumbersome, leading to greatly increased the complexity of intra prediction algorithm.To reduce computational complexity, the paper presents a new intra prediction algorithm selection. Improved algorithm idea is:First of all, I predict a macroblock, do not have to calculate the4×4luminance block prediction9modes and the16X16luminance block prediction modes. Because less detail macroblock is suitable for16×16luminance block prediction, more details macroblock is suitable for4×4luminance block prediction.When the macro-block type is clear, we can use only calculated4×4luminance block9predictive modes (144times)or16×16luminance blocks of four kinds of prediction mode(4times), not all the patterns of the two types are calculated, and only when the macro-block type is not clear,need the original algorithm are calculated. Thus improved algorithm saves the calculated frequency and to reduce the H.264coding complexity of purposes.Determined that the macro-block type, according to the adjacent pixels of the image relationship to be judged. Finally, the improved algorithm and the original intra prediction algorithm comparison,Experimental results show that a new intra prediction algorithm selection greatly enhance the coding speed1.6-4.1times. when ensuring the capability of the image quality and the Bits rate.