网络视频传输的两级不均等差错保护策略

传统的基于端到端的一级视频差错保护方案大多没有考虑有线与无线混合网络的包丢失原因的差别，所以整体效率不高。为此，针对有线无线混合网络的特征，提出一种基于H．264数据分割的混合动态不均等差错保护策略。接收端可对有线和无线网络上不同原因导致的丢包进行区分，视频服务器通过接收的RTCP（Real—Time Control Protocol）反馈，利用RS（Reed—Solomon）码和LDPC（Low Density Parity Code）码分别对抗网络中的丢包和误比特，针对H．264数据分类的重要性不同以及信道质量的变化，给予不同程度的动态保护。实验结果表明，这种两级保护混合抗误码算法与传统的基于包的端到端一级不均等差错保护相比，冗余度降低了约15％，而接收的视频质量提升了约4dB，且很大程度地提高客户端接收的有效数据率，为解码器进行差错隐藏奠定了良好的基础。

Two-Level Unequal Error Protection in Video Transmission over Networks

Conventional end-to-end error protection schemes for video transmission over wired-cum-wireless networks are only on packet-level without considering the loss difference between the wired networks and wireless networks, so the bandwidth utilization is not efficient. An adaptive hybrid unequal error protection scheme based on H. 264 data partition is proposed. The receiver can discriminate the causes of lost packets due to congestion or wireless link error. According to received RTCP feedback, the video server adopts RS （Reed-Solomon） code and LDPC （Low Density Parity Code） to resist packet erasure and bit error respectively, and unequal redundant levels are dynamically applied to data partitions of H. 264 video with different importance. The experiment results manifest that compared with classic packet-based end-to-end UEP protection this scheme can improve video quality for about 4 dB and save about 15% bandwidth at the same time. The received more effective video data is a good base for error concealments of video decoders.