The Research Of Rate Control Algorithm Based On H.264

With the development of the computer network and multimedia technology, digital video technology has been applied widely in today's society. As a new generation of video coding standard, H.264 has made obvious progress in coding efficiency by using a series of advanced coding tools in the encoding process. Because of the excellent performance, H.264 would be used in more application areas in the future.For the process of video communication, in order to meet the bandwidth requirement, it is necessary to control the bit rate effectively to get the best compromise between output rate and the coding quality. Rate control is one of key techniques in H.264, which will affect the performance of the video coding network transmission directly.Based on the JM8.6 model, by analyzing several disadvantages of the allocation scheme of frame-layer target bits, a new algorithm for frame-layer rate control is proposed in this paper. By modifying the calculation of the frame-layer complexity, considering the picture complexity, the neighborhood frame difference and the encoded frame feedback information, the proposed algorithm can adaptively adjust the number of the frame-layer target bits and QP, which makes bit allocation of the video sequence more rationally. At the same time, this paper also improves the process of RDO in the macroblock layer. Based on the prediction bits of the macroblock, the lagrange coefficient has been modified adaptively.Simulations demonstrate that the proposed algorithm can increase the PSNR, allocate the target bits logically and improve the quality of video coding significantly. Simultaneously, it can reduce the MSE of PSNR, which makes the coding quality more stable.