基于H.264帧层码率控制算法的改进

JVT-G012 is a kind of rate control algorithm, which is adopted by H.264/AVC, and includes GOP layer rate control, frame layer rate control and basic unit layer rate control. Analyzing the frame layer rate control algorithm, it can be found that the original algorithm does not consider the complexity of the image when it allocates the target bit for P frames, so it can’t adapt the unsmooth scene or movement changes. Therefore this paper improves the deficiencies in the target bit allocation algorithm, determines the image complexity based on the histogram of brightness difference between the before and after frames, designs a rate adjustment factor in accordance with HOD, then considers the different importance in coding of the P frame in different positions in the GOP, so a new integrated target bit allocation algorithm is proposed. Experimental results show that compared with the JVT-G012 algorithm, considering the image complexity and the importance of different locations, the new algorithm can obtain higher PSNR value and control the output bits more accurately.