一种动态自适应HTTP流媒体码率切换算法

A Dynamic Adaptive Bitrate Switching Algorithm for HTTP Streaming

近年来,基于HTTP的动态自适应流媒体技术,已经被各种网络视频播放服务广泛采用.针对客户端缓冲区受限和网络环境不稳定的情况,提出一种基于客户端缓冲区长度的动态自适应码率选择算法.该算法通过对缓冲区进行分级实现了带宽的不同比例的缩放,并采用滑动窗口技术对带宽进行平滑处理.同时,通过设置每个缓冲区等级的带宽持续上升或下降时间的限制和采用高低带宽的中间码率等级,使码率等级不会剧烈变化.实验结果表明,该算法能在带宽利用和视频质量的平滑之间取得较好的平衡,提供良好的视频播放用户体验.

Recently,Dynamic Adaptive Streaming over HTFP has been widely used among many popular online video services. With limited client buffer and varying network, this paper proposes a client buffer length base dynamic bitrate switching algorithm. Client buffer is divided into several buffer levels with different bandwidth zoom proportions. Sliding window technique is used to analyze download bandwidth variation of recent video segments. Continuous bandwidth ascension or reduction is required to switch bitrate, and a modest bitrate level between low and high bandwidth is selected to avoid dramatic change of bitrate. Experiment results show that the proposed algorithm can achieve a good balance between bandwidth utilization and supplying smooth video content.