H.264 FMO码流率失真优化调度算法

Scheduling Algorithm for Rate-Distortion Optimization of H.264 FMO Stream

相对于TCP(Transmission Control Protocol),UDP(User Datagram Protocol)的及时性更好,但分组丢失使其不能直接应用于流媒体传输.文中通过实验分析了采用FMO(Flexible Macroblock Ordering)编码选项的H.264码流的抗误码性能,建立了UDP信道模型,并针对流媒体实时传输遇到的抗误码和及时性问题,提出了H.264 FMO码流率失真优化调度算法.该算法根据UDP信道变化调整传输参数,获得最小的传输率失真.仿真结果表明,相对于其它的调度算法,该算法在UDP信道环境下可以获得更优越的传输性能,并保证了UDP分组对TCP分组的友好性.

As compared with Transmission Control Protocol （TCP）, User Datagram Protocol （UDP） works more timely, but the packet lose limits its application to real-time streaming media transmission. In order to solve this problem, the error resilience of H. 264 bit-stream adopting Flexible Macroblock Order （FMO） is analyzed by ex- periments, and an UDP channel model is established. Moreover, in order to solve the error resilience and the realtime transmission problems, a scheduling algorithm for rate-distortion optimization of H. 264 FMO stream is proposed. By the proposed algorithm, a minimum rate distortion can be achieved because transmission parameters can vary with the UDP channel situation. Simulated results indicate that the proposed algorithm outperforms other scheduling algorithms due to its high transmission performance in UDP channel situation and the friendship of UDP packet to TCP packet.