一种内容感知的H.264视频分组打包策略  

Content-aware Packetization Strategy for H. 264 Video

作　　者：李志鹏[1] 卢汉成[1] 洪佩琳[1] 

机构地区：[1]中国科学技术大学信息网络实验室,合肥230027

出　　处：《小型微型计算机系统》2014年第5期1188-1191,共4页Journal of Chinese Computer Systems

基　　金：国家自然科学基金项目(61170231)资助

摘　　要：提出一种基于内容感知的分组打包策略来增强已编码的H.264视频流在带宽受限、易错的无线信道下的传输性能.H.264分片的优先级依照其对接收端视频质量的影响来划分,不仅考虑了该分片丢失对包含该分片的视频帧解码重建带来的瞬时失真,还考虑了由于H.264编码采用运动预测而对其它视频帧的造成的错误扩散失真.不同优先级的分片将会组成合适大小的不同优先级的分组进行传输,调度时只需优先调度高优先级分组,低优先级分组若超过解码时限仍未被成功传输将会被丢弃.推导出了在不同码率和信道误比特率下,使得加权实际吞吐量最大的各优先级最优分组大小.仿真结果表明提出的基于内容感知的分组打包策略显著改善了H.264视频流在无线环境下的传输性能.This paper introduced a content-aware packetization strategy to enhance the quality of pre-encoded H. 264 video streams o- ver bit-rate limited error-prone links in wireless networks. The H. 264 slices are classified in different priorities at the encoder based on their contribution to the received video quality. Once a slice is lost, it will cause instantaneous transmission distortion in the recon- structed frame to which the lost slice belongs. Besides, the loss of a slice might also result in distortions in subsequent frames within the current GOP due to error propagation. We use the overall transmission distortion caused by the loss of the slice to assign slice pri- ority. The slices of a priority class are aggregated into packets of corresponding priority, the link layer scheduler transmits all high pri- ority packets before low priority ones every second, any packet after its decoding deadline has expired must be dropped since it has lost its value to the decoder. We derive the optimal packet size for each priority level which achieves the maximum weighted goodput at different encoded video bit rates and channel bit error rates. Simulation results show that the proposed content-aware strategy pro- vides considerably improved video quality.

关 键 词：H 264 内容感知 打包策略 视频质量 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]