A reformative frame layer rate control algorithm for H.264

Rate control is an important part of video coding. There are two disadvantages in frame layer rate control of JVT-G012 proposal for H.264 video coding standard. One is that the bit allocation in frame layer is uniform and another is that it does not take the encoded frame information into account. This paper presents a reformative frame layer rate control algorithm by combining frame complexity and adjusting quantization parameter (QP). The target bits of each frame are allocated based on its complexity coefficient and then its quantization parameter is adjusted by encoded frame information. Experimental results show that the proposed algorithm, in comparison to the original algorithm, reduced the actual bitrate error of video sequences by almost one times, improved average peak signal noise ratio (PSNR) by 0.64 dB and got a smaller PSNR deviation by 29.32%. The algorithm can not only control bitrate more accurately, but also get video image quality better and smoother with lower coding buffer occupancy^.