联合编码模式选择的码率控制算法

Joint Coding Mode Selection and Rate Control Algorithm

本文提出了一种丢包网络中联合信源信道码率控制算法 .该算法克服了以往码率控制方法和误码复原技术互不关联的弊病 ,在统计率失真模型的基础上 ,联合最优地计算图像级量化参数和寻找最佳宏块编码模式 ,在给定的受限码率下能充分利用可用信道带宽 ,使得视频信源编码和信道传输总失真最小 .实验结果表明该算法能够获得比传统算法更高的性能增益 .

We present a statistics analysis of the picture distortion caused by quantization, channel errors and subsequent error propagation, and propose rate-distortion estimation models which are functions of two parameters, quantization step and intra refreshing ratio. Based on these R-D models, a joint optimal quantization step and intra refreshing ratio selection algorithm is developed by using Lagrange multiplier theory. Simulation results show that our algorithm can make the encoder adapting itself in time to the variation of the channel bandwidth, and significantly improve the video quality over packet loss networks.