FGS视频流的码率分配算法研究

Rate Allocation for MPEG-4 FGS Video Streaming

该文针对精细可分级编码(FGS)比特流在时变带宽网络上的传输,提出了一种基于视频序列率失真(R-D)特性的FGS增强层的码率分配算法,目标是减少接收端解码视频质量的波动,同时保持视频总体质量最优。首先建立一个在多帧图像增强层之间进行码率分配的最优化问题形式,并进行了合理的简化,然后利用线性内插原则建立描述各帧图像增强层率失真特性的R-D模型。由于各帧图像R-D曲线的单调特性,如此建立起来的最优化问题可以用简单的算法求出最优解。仿真结果表明,这个方案在保证解码视频质量恒定和保持视频总体质量最优两方面均收到了良好的效果,同时该方案的简易性使得它的实现和应用成为可能。

A new rate allocation method based on video R-D characteristics of MPEG-4FGS enhancement layer in its streaming application on time-varying-bandwidth network is proposed.This method aims to minimize the image quality fluctuation on the receiver side and maintain overall perfect quality at the same time.First,an optimization model for distributing bit rate among a number of frames is established and then is simplified in a reasonable way.Second,a R-D model is established using linear interpolation to describe the rate-distortion relation for each frame enhancement layer.Duo to the descending characteristics of R-D curve,the optimization problem mentioned can be solved in a simple way.It can be concluded from the final simulation results that this rate allocation method has achieved perfect outcome in smoothing video quality fluctuation and maintaining overall perfect video quality and that its simpleness enables its re-alization and application.