基于Cauchy分布的二次RDO编码码率控制算法  

Cauchy-distribution-based rate control algorithm via twice rate distortion optimization coding

作　　者：费伟[1] 朱善安[1] 

机构地区：[1]浙江大学电气工程学院,浙江杭州310027

出　　处：《浙江大学学报（工学版）》2008年第4期636-640,共5页Journal of Zhejiang University：Engineering Science

摘　　要：为提高码率控制精度和图像质量,通过基于Cauchy分布源模型的率失真分析,得出了精确的码率(RQ)模型和失真(DQ)模型,在此基础上提出了一种低码率下的宏块层码率控制算法.该算法在宏块层上利用新的RQ模型计算量化参数,并采用率失真优化技术(RDO)对部分宏块进行二次编码,从而进一步优化选择编码模式,提高了编码效率.实验结果表明,与H.264参考软件JM 8.6中采用的码率控制算法相比,该算法得到的平均峰值信噪比最大提高了0.81 dB,而且能显著降低比特数估计偏差,更准确地进行码率控制.An accurate rate-quantization （RQ） model and a distortion-quantization （DQ） model were developed through Cauchy-distribution-based rate-distortion analysis to improve the accuracy of rate control and image quality. Based on the new models, a novel macroblock level rate control scheme was proposed for low bit rate application. This scheme computes the quantization parameters of macroblocks by the new RQ model, and optimally selects the macroblock coding mode by partial twice coding through rate distortion optimization （RDO）. Experimental results show that the proposed algorithm can improve the average peak signal to noise ratio by up to 0.81 dB, decrease significantly bit estimation error, and control the rate more accurately, compared with the rate control algorithm of H. 264 reference software JM 8.6.

关 键 词：码率控制 率失真模型 Cauchy分布 率失真优化 部分二次编码 

分 类 号：TN919.8[电子电信—通信与信息系统]