动态自适应的HTTP流码率渐进切换算法
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摘要
针对在动态网络环境和有限缓存容量限制下用户观看视频体验质量低的问题,提出一种综合考虑带宽和缓存因素的动态自适应的HTTP流码率渐进切换(DASBS)算法。首先,利用滑动窗口分析最近下载分片得到带宽初步估值;然后,依据实时带宽波动程度和缓存状态设置双矫正因子进一步平滑带宽估值;最后,设置缓存阈值使其与当前码率建立相关关系,并利用带宽估值和缓存动态阈值共同控制码率切换。使用libdash平台验证算法性能,DASBS在切换平滑性上优于VQCQ(Video Quality Control for QoE)算法,视频播放平均码率更高,有效提高了带宽利用率;平均码率稍低于EABS(Evolution of Adaptive Bitrate Switching)算法时,切换次数得到大幅下降,整体切换稳定性表现更优。实验结果表明,所提算法在动态网络环境中具有带宽高利用、切换平滑和切换稳定的良好表现,能够有效改善用户体验。
Aiming at the problem of low quality of video viewing experience in dynamic network environment with limited cache capacity, a Dynamic Adaptive Step-wise Bitrate Switching(DASBS) algorithm for HTTP streaming considering network bandwidth and cache capacity was proposed. Firstly, a sliding window was used to analyze the recent downloaded fragments, obtaining the initial bandwidth estimation. Then, according to the real-time bandwidth fluctuation degree and cache state, two correction factors were set to further smooth the bandwidth estimation. Finally, a cache threshold was set to establish a correlation with the current bitrate, and the bandwidth estimation and the cache dynamic threshold were used to jointly control the bitrate switching. Experimental results on platform libdash show that DASBS is better than Video Quality Control for QoE(VQCQ) algorithm in switching smoothness and its average bitrate of video playback is higher, which effectively improves the bandwidth utilization. Although the average bitrate is slightly lower than that of Evolution of Adaptive Bitrate Switching(EABS) algorithm, the number of switching times is greatly reduced, improving the switching stability. The experimental results show that the proposed algorithm has high bandwidth utilization, switching smoothness and switching stability in dynamic network environment, which can effectively improve user experience.
Aiming at the problem of low quality of video viewing experience in dynamic network environment with limited cache capacity, a Dynamic Adaptive Step-wise Bitrate Switching(DASBS) algorithm for HTTP streaming considering network bandwidth and cache capacity was proposed. Firstly, a sliding window was used to analyze the recent downloaded fragments, obtaining the initial bandwidth estimation. Then, according to the real-time bandwidth fluctuation degree and cache state, two correction factors were set to further smooth the bandwidth estimation. Finally, a cache threshold was set to establish a correlation with the current bitrate, and the bandwidth estimation and the cache dynamic threshold were used to jointly control the bitrate switching. Experimental results on platform libdash show that DASBS is better than Video Quality Control for QoE(VQCQ) algorithm in switching smoothness and its average bitrate of video playback is higher, which effectively improves the bandwidth utilization. Although the average bitrate is slightly lower than that of Evolution of Adaptive Bitrate Switching(EABS) algorithm, the number of switching times is greatly reduced, improving the switching stability. The experimental results show that the proposed algorithm has high bandwidth utilization, switching smoothness and switching stability in dynamic network environment, which can effectively improve user experience.
引文
[1]Cisco.White paper:Cisco VNI forecast and methodology,2015-2020[EB/OL].[2017-08-14].https://www.cisco.com/c/en/us/solutions/collateral/service-provider/.
[2]夏勃,林浒,李鸿彬,等.一种动态自适应HTTP流媒体码率切换算法[J].小型微型计算机系统,2015,36(2):275-279.(XIA B,LIN H,LI H B,et al.A dynamic adaptive HTTP streaming rate switching algorithm[J].Journal of Chinese Computer Systems,2015,36(2):275-279.)
[3]ZHAO S,LI Z,MEDHI D,et al.Study of user Qo E improvement for dynamic adaptive streaming over HTTP(MPEG-DASH)[C]//Proceedings of the 2017 International Conference on Computing,Networking and Communications.Piscataway,NJ:IEEE,2017:566-570.
[4]MOK R K P,LUO X,CHAN E W W,et al.QDASH:a Qo E-aware DASH system[C]//MMSys 2012:Proceedings of the 3rd Multimedia Systems Conference.New York:ACM,2012:11-22.
[5]TIMMERER C.A test-bed for the dynamic adaptive streaming over HTTP featuring session mobility[C]//MMSys 2011:Proceedings of the 2nd Annual ACM Conference on Multimedia Systems.New York:ACM,2011:271-276.
[6]LI Z,ZHU X,GAHM J,et al.Probe and Adapt:Rate adaptation for HTTP video streaming at scale[J].IEEE Journal on Selected Areas in Communications,2014,32(4):719-733.
[7]LE H T,NGUYEN D V,NGOC N P,et al.Buffer-based bitrate adaptation for adaptive HTTP streaming[C]//ATC 2013:Proceedings of the 2013 International Conference on Advanced Technologies for Communications.Piscataway,NJ:IEEE,2013:33-38.
[8]SPITERI K,URGAONKAR R,SITARAMAN R K.BOLA:nearoptimal bitrate adaptation for online videos[C]//IEEE INFOCOM2016:Proceedings of the 35th Annual IEEE International Conference on Computer Communications.Piscataway,NJ:IEEE,2016:1-9.
[9]LEE S,YOUN K,CHUNG K.Adaptive video quality control scheme to improve Qo E of MPEG DASH[C]//Proceedings of the2015 IEEE International Conference on Consumer Electronics.Piscataway,NJ:IEEE,2015:126-127.
[10]MLLER C,LEDERER S,TIMMERER C.An evaluation of dynamic adaptive streaming over HTTP in vehicular environments[C]//Mo Vid 2012:Proceedings of the 4th Workshop on Mobile Video.New York:ACM,2012:37-42.
[11]陈立伟,李国平,滕国伟,等.基于HTTP流化的自适应码率混合控制算法[J].上海大学学报(自然科学版),2014,20(3):313-320.(CHEN L W,LI G P,TENG G W,et al.Adaptive code rate hybrid control algorithm based on HTTP streaming[J].Journal of Shanghai University(Natural Science),2014,20(3):313-320.)
[12]KESAVAN S,JAYAKUMAR J.Improvement of adaptive HTTPstreaming using advanced real-time rate adaptation[J].Computers&Electrical Engineering,2017,58:49-66.
[13]KUA J,ARMITAGE G,BRANCH P.A survey of rate adaptation techniques for dynamic adaptive streaming over HTTP[J].IEEECommunications Surveys&Tutorials,2017,19(3):1842-1866.
[14]祝谷乔,宋皓.MPEG-DASH与HLS流传输技术的比较分析[J].电信科学,2015,31(4):23-27.(ZHU G Q,SONG H.Comparative Analysis of MPEG-DASH and HLS streaming technology[J].Telecommunications Science,2015,31(4):23-27.)
[15]Libdash[EB/OL].[2016-12-11].https://github.com/bitmovin/libdash.
[2]夏勃,林浒,李鸿彬,等.一种动态自适应HTTP流媒体码率切换算法[J].小型微型计算机系统,2015,36(2):275-279.(XIA B,LIN H,LI H B,et al.A dynamic adaptive HTTP streaming rate switching algorithm[J].Journal of Chinese Computer Systems,2015,36(2):275-279.)
[3]ZHAO S,LI Z,MEDHI D,et al.Study of user Qo E improvement for dynamic adaptive streaming over HTTP(MPEG-DASH)[C]//Proceedings of the 2017 International Conference on Computing,Networking and Communications.Piscataway,NJ:IEEE,2017:566-570.
[4]MOK R K P,LUO X,CHAN E W W,et al.QDASH:a Qo E-aware DASH system[C]//MMSys 2012:Proceedings of the 3rd Multimedia Systems Conference.New York:ACM,2012:11-22.
[5]TIMMERER C.A test-bed for the dynamic adaptive streaming over HTTP featuring session mobility[C]//MMSys 2011:Proceedings of the 2nd Annual ACM Conference on Multimedia Systems.New York:ACM,2011:271-276.
[6]LI Z,ZHU X,GAHM J,et al.Probe and Adapt:Rate adaptation for HTTP video streaming at scale[J].IEEE Journal on Selected Areas in Communications,2014,32(4):719-733.
[7]LE H T,NGUYEN D V,NGOC N P,et al.Buffer-based bitrate adaptation for adaptive HTTP streaming[C]//ATC 2013:Proceedings of the 2013 International Conference on Advanced Technologies for Communications.Piscataway,NJ:IEEE,2013:33-38.
[8]SPITERI K,URGAONKAR R,SITARAMAN R K.BOLA:nearoptimal bitrate adaptation for online videos[C]//IEEE INFOCOM2016:Proceedings of the 35th Annual IEEE International Conference on Computer Communications.Piscataway,NJ:IEEE,2016:1-9.
[9]LEE S,YOUN K,CHUNG K.Adaptive video quality control scheme to improve Qo E of MPEG DASH[C]//Proceedings of the2015 IEEE International Conference on Consumer Electronics.Piscataway,NJ:IEEE,2015:126-127.
[10]MLLER C,LEDERER S,TIMMERER C.An evaluation of dynamic adaptive streaming over HTTP in vehicular environments[C]//Mo Vid 2012:Proceedings of the 4th Workshop on Mobile Video.New York:ACM,2012:37-42.
[11]陈立伟,李国平,滕国伟,等.基于HTTP流化的自适应码率混合控制算法[J].上海大学学报(自然科学版),2014,20(3):313-320.(CHEN L W,LI G P,TENG G W,et al.Adaptive code rate hybrid control algorithm based on HTTP streaming[J].Journal of Shanghai University(Natural Science),2014,20(3):313-320.)
[12]KESAVAN S,JAYAKUMAR J.Improvement of adaptive HTTPstreaming using advanced real-time rate adaptation[J].Computers&Electrical Engineering,2017,58:49-66.
[13]KUA J,ARMITAGE G,BRANCH P.A survey of rate adaptation techniques for dynamic adaptive streaming over HTTP[J].IEEECommunications Surveys&Tutorials,2017,19(3):1842-1866.
[14]祝谷乔,宋皓.MPEG-DASH与HLS流传输技术的比较分析[J].电信科学,2015,31(4):23-27.(ZHU G Q,SONG H.Comparative Analysis of MPEG-DASH and HLS streaming technology[J].Telecommunications Science,2015,31(4):23-27.)
[15]Libdash[EB/OL].[2016-12-11].https://github.com/bitmovin/libdash.