考虑全帧间参考依赖性的监控视频高效视频编码码率控制算法

Rate Control for High Efficiency Video Coding Coded Surveillance Videos Considering All of the Inter-Frame Reference Dependency

针对高效视频编码(HEVC)标准中的码率控制算法在计算目标码率分配权重时未考虑帧间参考依赖性、编码效率低的问题,提出了一种面向监控视频考虑全帧间参考依赖性的HEVC图像级码率控制算法。调研了HEVC低时延结构中编码帧与其所有帧间参考帧之间的参考依赖关系,在此基础上构建了适用于监控视频的考虑全帧间参考依赖性的失真模型。利用构建的失真模型,基于拉格朗日率失真优化理论,建立了拉格朗日率失真代价函数。求解此代价函数,获得每幅图像对应的优化的目标码率分配权重,提出了适用于监控视频的图像级码率控制算法。实验结果表明,与HEVC测试模型HM中使用的平均比率目标码率分配权重的码率控制算法相比,所提算法可以获得更加准确的码率估计,并且所提算法的德尔塔码率(ΔR)可平均降低9.54%。

To solve the problems that rate control in high efficiency video coding(HEVC)standard does not consider the inter-frame reference dependency when calculating the target bitrate allocation weight,and the coding efficiency is low,a picture level rate control method considering all of the inter-frame reference dependency for HEVC coded surveillance videos is proposed.A new distortion model for surveillance video is constructed following the investigation of the reference dependency between the coding frame and all of its referenced inter-frames in the low-delay structure of HEVC.Adopting the Lagrangian rate-distortion(R-D)optimization theory,the Lagrangian R-D cost function is established according to the constructed distortion model.The optimized bit allocation weights for pictures are solved from the R-D cost function,and a picture level rate control algorithm for surveillance videos is obtained.Compared with the rate control algorithm in HEVC test model using equal target bitrate allocation weights,the proposed algorithm achieves a more accurate bitrate estimation.Moreover,the Bjntegaard delta-rate(ΔR)of the proposed algorithm can be reduced by 9.54%on average.