Journal of Computer Applications ›› 2019, Vol. 39 ›› Issue (4): 1122-1126.DOI: 10.11772/j.issn.1001-9081.2018091933

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Rate smooth switching algorithm based on DASH standard

HUANG Sheng1,2, FU Yuanpeng1,2, ZHANG Qianyun1,2   

  1. 1. School of Communication and Information Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China;
    2. Chongqing Key Laboratory of Optical Communications and Networking(Chongqing University of Posts and Telecommunications), Chongqing 400065, China
  • Received:2018-09-17 Revised:2018-10-30 Online:2019-04-10 Published:2019-04-10
  • Supported by:
    This work is partially supported by the National Natural Science Foundation of China (61371096, 61571072).


黄胜1,2, 付园鹏1,2, 张倩云1,2   

  1. 1. 重庆邮电大学 通信与信息工程学院, 重庆 400065;
    2. 重庆市光通信与网络重点实验室(重庆邮电大学), 重庆 400065
  • 通讯作者: 付园鹏
  • 作者简介:黄胜(1974-),男,重庆人,教授,博士,CCF会员,主要研究方向:视频传输、视频编码、机器学习;付园鹏(1992-),男,湖北宜昌人,硕士研究生,主要研究方向:视频传输;张倩云(1995-),女,四川雅安人,硕士研究生,主要研究方向:视频传输、视频编码。
  • 基金资助:

Abstract: Concerning the fact that the existing rate adaptation algorithms based on Dynamic Adaptive Streaming over HTTP (DASH) have frequent bitrate switching and low average bitrate in wireless network, a Rate Smooth Switching (RSS) algorithm based on DASH standard was proposed. Firstly, a sliding window was used by the bandwidth detection mechanism of the algorithm to sample the download speed of historical segments to calculate the bandwidth offset coefficient, the fluctuation of the bandwidth was initially determined according to the value of offset coefficient, and the situation of the fluctuation was further determined whether there was a consistent variation trend, thereby distinguishing continuous variation and short-term jitter of the bandwidth, and the bandwidth prediction value corresponding to each circumstance was calculated. Secondly, with bandwidth fluctuation, buffer occupancy and variation, bandwidth prediction value considered, the rate decision model of the algorithm adopted Fast Buffering (FB), Slow Switching (SS), Fast Rising (FR), Limited Declining (LD), Stable Holding (SH) strategies and sleeping mechanism to dynamically control the video bitrate selection process. The experimental results show that compared with fuzzy-based DASH rate adaptation algorithm and modulated throughput driven rate adaptation algorithm, the proposed algorithm can not only increase the bitrate to optimum level in the shortest time at the beginning of video playback to improve the average bitrate, but also minimize the number of bitrates' switching in the case of sudden change and frequent fluctuation of bandwidth, thus obtaining a good quality of experience for wireless video users.

Key words: wireless network, Dynamic Adaptive Streaming over HTTP (DASH), bandwidth detection, consistent variation trend of bandwidth, Quality of Experience (QoE)

摘要: 针对现有的基于超文本传输协议的动态自适应流(DASH)码率自适应算法在无线网络环境中码率切换频繁以及平均码率偏低的问题,提出一种基于DASH标准的码率平滑切换(RSS)算法。首先,算法的带宽检测机制利用滑动窗口对历史下载速率进行取样以计算带宽偏移系数,根据带宽偏移系数的大小初步判断带宽的波动情况,并对波动较大的情况进一步确定是否存在一致性变化趋势,从而区分出带宽的持续变化和短暂抖动,同时计算出相应情况下的带宽预测值;其次,算法的码率决策模型综合考虑带宽波动情况、缓存占用和变化情况及带宽预测值等,并且分别采取快速缓冲(FB)、缓慢切换(SS)、快速上升(FR)、约束下降(LD)、稳定保持(SH)策略和休眠机制对码率选择过程进行动态控制。实验结果表明,与基于模糊逻辑的码率自适应算法以及吞吐量调节驱动的码率自适应算法相比,该算法在播放开始时能够在最短时间内将视频码率提升到最佳水平,提高视频播放过程中的平均码率,在播放过程中带宽骤变和交替性频繁波动情况下都能够很好地维持视频码率的稳定,将切换次数降到最低,从而获得良好的无线端视频体验质量。

关键词: 无线网络, 基于超文本传输协议的动态自适应流, 带宽检测, 带宽一致性变化趋势, 体验质量

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