MPEG-4 FGS视频流量模型的仿真应用研究

MPEG-4 FGS Video Traffic Model and Its Application in Simulation

针对MPEG-4 FGS可伸缩的视频流量,采用马尔可夫链调制的一阶自回归方法对其统计特性进行建模,通过与Trace流量的仿真结果对比,证明了该模型的有效性。在此基础上,提出了基于FGS流量模型的层次化速率控制方法,在NS-2中将该方法与三种典型的CBR层次流量模型方法对分层视频组播RLM协议性能的影响进行了仿真实验对比。仿真结果表明:采用CBR模型来模拟MPEG-4 FGS层次流量对RLM协议进行性能仿真评价存在较大的误差,采用所提出的基于FGS流量模型的层次化速率控制方法对自适应视频组播协议的性能进行仿真具有更好的精确性。

To simulate actual video traffic in performance evaluation of adaptive video multicast protocols, we first introduce Markov chain modulated first order autoregressive process to model the statistical properties of MPEG - 4 FGS layered video traffic, and verify the availability of the proposed model compared with the video trace in NS - 2. We then present a layered rate control method based on the proposed FGS traffic model, and design three simulation experiments on RLM, each adopting the proposed rate control method based on FGS model and one of three typical CBR layered traffic models respectively. The experiments reveal that the result of our scheme differs greatly from those of CBR schemes. Since our FGS model is more accurate than the CBR models, we suggest that layered rate control method based on FGS traffic model is more desirable in the simulations of adaptive video multicast protocols to get more accurate evaluation results.