保证H.264视频通信质量的实时传输协议载荷

Real-Time Transport Protocol Payload for Guaranteeing the QoS of H.264 Video Delivery

在详细研究H.264标准的网络适配层（NAL）和实时传输协议（RTP）的基础上,提出一种可以保证H.264视频通信质量的实时传输协议（ERRTP）载荷结构,载荷结构中使用了NAL头字段和前向纠删（FEC）保护字段,在增加开销很小的情况下,支持对H.264视频码流进行FEC不等保护,同时可以保证时延在实时视频通信允许的范围内.性能分析和实验结果表明,与RTP协议相比,使用ERRTP载荷的传输效率基本没有变化,且ERRTP支持FEC不等保护,与单一FEC保护相比,在高丢包率下恢复视频质量的峰值信噪比可以提高2-9 dB,满足分组丢失环境下实时视频通信的服务质量要求.

On the basis of detailedly researching on real-time transport protocol （RTP） and network adaptation layer （NAL） of video coding standard H. 264, a payload format of real-time transport protocol for guaranteeing QoS of H. 264 video delivery over IP network is proposed, in which the NAL header and the forward erasure correction （FEC） field is employed. With less extra overhead, the proposed payload can support FEC unequal-protection for H. 264 video stream and ensures the delay to be in allowable range for real-time video delivery. Performances analysis and experimental results show that compared with RTP, the transmission efficiency using ER- RTP is basically not changing and ERRTP supports FEC unequal-protection,and compared with single FEC protection, the PSNR of recovery video quality can be increased by 2-9 dB, which satisfies QoS demands of real-time video communication under packet drop environment.