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计算机工程 ›› 2018, Vol. 44 ›› Issue (11): 306-312. doi: 10.19678/j.issn.1000-3428.0048773

• 开发研究与工程应用 • 上一篇    下一篇

一种基于多服务器的DASH客户端优化算法

吴如亮,王子磊,奚宏生   

  1. 中国科学技术大学 自动化系,合肥 230027
  • 收稿日期:2017-09-25 出版日期:2018-11-15 发布日期:2018-11-15
  • 作者简介:吴如亮(1991—),男,硕士研究生,主研方向为网络多媒体技术;王子磊,副教授;奚宏生,教授。
  • 基金资助:

    国家自然科学基金重点项目“三网融合业务接入系统的分析、建模与调控”(61233003)

A DASH Client Optimization Algorithm Based on Multiple Servers

WU Ruliang,WANG Zilei,XI Hongsheng   

  1. Department of Automation,University of Science and Technology of China,Hefei 230027,China
  • Received:2017-09-25 Online:2018-11-15 Published:2018-11-15

摘要:

在多服务器场景下,基于HTTP的动态自适应流媒体在传输过程中,由于用户请求的高度动态性及多服务器传输带宽的差异性,客户端获取的视频质量波动较频繁,影响到用户体验质量。针对上述问题,提出一种基于软件定义网络的视频分片请求调度算法。将多个分片组成一个视频块,利用分配策略把这多个分片分配至多个服务器,实现同一视频块内视频分片的码率同步,并使分片有序下载。同时,客户端算法采用Q学习方法,根据不同的环境状态决策出相应的码率。仿真实验结果表明,该算法可减少视频质量的波动,提高客户端平均视频质量。

关键词: 基于HTTP的动态自适应流媒体, 多服务器, 体验质量, 质量波动, 软件定义网络, Q学习

Abstract: In the transmission of Dynamic Adaptive Streaming over HTTP(DASH) for scenario,the client’s video quality would fluctuate much frequently due to the user’s high dynamic request and different transmission bandwidths of multiple servers.Such fluctuation would affect the Quality of Experience(QoE) seriously.To solve this problem,this paper proposes a video fragment request scheduling algorithm based on Software-Defined Network(SDN).By considering several video segments as one video block,these segments are assigned to a series of servers through an allocation strategy.This two-step method can not only realize the bit rate synchronization of the video segments in the same video block,but also enable the segments to be downloaded in an orderly manner.Furthermore,the client algorithm uses Q-learning method to deduce bit rate depending on different environmental state.Experimental results show that the proposed algorithm can reduce the fluctuation of video quality and improve the average video quality of the client.

Key words: Dynamic Adaptive Streaming over HTTP(DASH), multiple servers, Quality of Experience(QoE), quality oscillation, Software-Defined Network(SDN), Q-earning

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