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计算机工程 ›› 2013, Vol. 39 ›› Issue (2): 1-5. doi: 10.3969/j.issn.1000-3428.2013.02.001

• 专栏 • 上一篇    下一篇

一种实时自适应HTTP流化码流切换算法

张辉帅 1,2,王劲林 2,朱小勇 2,孙 鹏 2   

  1. (1. 中国科学院研究生院,北京 100039;2. 中国科学院声学研究所国家网络新媒体工程技术研究中心,北京 100190)
  • 收稿日期:2012-03-26 修回日期:2012-05-24 出版日期:2013-02-15 发布日期:2013-02-13
  • 作者简介:张辉帅(1988-),男,硕士研究生,主研方向:多媒体流化,宽带通信;王劲林,研究员、博士生导师;朱小勇、孙 鹏,副研究员、博士
  • 基金资助:

    国家“863”计划基金资助项目“融合网络业务体系的开发”(2011AA01A102);国家科技支撑计划基金资助项目“数字家庭服务媒体设备集成技术研究”(2011BAH16B03);中国科学院战略性先导科技专项基金资助项目子课题“未来网络架构研究与边缘设备研制”(XDA06010302)

A Real-time Adaptive Bitstream Switching Algorithm for HTTP Streaming

ZHANG Hui-shuai 1,2, WANG Jin-lin 2, ZHU Xiao-yong 2, SUN Peng 2   

  1. (1. Graduate University of Chinese Academy of Sciences, Beijing 100039, China; 2. National Network New Media Engineering Research Center, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China)
  • Received:2012-03-26 Revised:2012-05-24 Online:2013-02-15 Published:2013-02-13

摘要:

根据终端拉服务模式的码流自适应匹配技术,提出一种实时自适应HTTP流化码流切换算法。利用滑动窗口分析最近视频分片的下载时间,采用假设检验方法确定在滑动窗口内是否发生速率跳变,以此估计平均下载速率和方差。应用Ek/D/1/N排队模型计算缓存区下溢的概率,对下溢风险和码流质量分别赋以损益值和收益值,计算出综合收益最高的码流作为目标码流。仿真结果证明,该算法能根据网络可用带宽实时调整传输码流,具有良好的码率跟踪性能。

关键词: HTTP流化, 码流切换, 滑动窗口, 假设检验, Ek/D/1/N排队模型

Abstract:

According to the adaptive bitstream matching technology of terminal services pull mode, this paper proposes a real-time adaptive bitstream switching algorithm for HTTP streaming. It uses the sliding window to analyze the time for downloading each video segmen. Hypothesis testing is used to judge whether there is a rate jump, which degrades the estimation significantly, in present observing window. The Ek/D/1/N queue is employed to model the number of segments in the receiver buffer and to figure out the underflow probability. Customized values of loss and benefit are set to underflow risk and stream quality respectively. A stream with optimal integrated benefit is considered to be the target stream. Experimental results show that the proposed algorithm can determine the appropriate downloading stream based on the current available bandwidth, with good performance of rate adaption.

Key words: HTTP streaming, bitstream switching, sliding window, hypothesis test, Ek/D/1/N queue model

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