基于缓冲区充盈度的自适应分段视频流量平滑

Buffer Filling Degree Based Adaptive Segmented Video Traffic Smoothing

可变比特率(VBR)视频在不同的时间尺度上存在流量突发的特性,采用流量平滑技术可以减弱或消除其突发性,提高网络带宽的利用率.基于对缓冲区充盈度函数的判断提出一种新的自适应分段流量平滑算法BFD_ASTS,在给定缓冲区容量和启动延时的情况下一次运行便可得出可行的传输规划.仿真实验表明,相对于固定分段算法PCRTT而言,BFD_ASTS在不同的缓冲区容量条件下能提供更优异的流量平滑性能;其50%左右的平均缓冲区利用率能更好的折中高效利用缓冲区和支持客户端VCR操作两方面的需求.另外,BFD_ASTS固定启动延时的特性,也更适用于实际的服务系统.

High burstiness and fluctuation are inevitable in variable rate videos （ VBR ） on different time scales, which could be reduced by applying the traffic smoothing techniques in order to achieve efficient use of network resources. An adaptive segmented traffic smoothing algorithm based on the judgment of the function of buffer filling degree （ BFDAS ） is presented in this paper. Given the video sequence, BFDAS could solve the feasible transmission scheme at first running. It is demonstrated that compared with the fixed segmented algorithm PCRTI＇, BFDAS could provide better smoothing performance under various buffer capacities, and because of the half average buffer utilization, it could also better balance the high efficiency utilization of the buffer against the need of supporting VCR operations for clients. Finally, the fixed start-up delay characteristic of BFDAS makes it more suitable in the practical service systems.