Transmission of variable bit rate (VBR) video, because of the burstiness of VBR video traffic, has high fluctuation in bandwidth requirement. Traffic smoothing algorithm is very efficient in reducing burstiness of the...Transmission of variable bit rate (VBR) video, because of the burstiness of VBR video traffic, has high fluctuation in bandwidth requirement. Traffic smoothing algorithm is very efficient in reducing burstiness of the VBR video stream by trans- mitting data in a series of fixed rates. We propose in this paper a novel segment-based bandwidth allocation algorithm which dynamically adjusts the segmentation boundary and changes the transmission rate at the latest possible point so that the video segment will be extended as long as possible and the number of rate changes can be as small as possible while keeping the peak rate low. Simulation results showed that our approach has small bandwidth requirement, high bandwidth utilization and low computation cost.展开更多
The alpha stable self-similar stochastic process has been proved an effective model for high variable data traffic. A deep insight into some special issues and considerations on use of the process to model aggregated ...The alpha stable self-similar stochastic process has been proved an effective model for high variable data traffic. A deep insight into some special issues and considerations on use of the process to model aggregated VBR video traffic is made. Different methods to estimate stability parameter a and self-similar parameter H are compared. Processes to generate the linear fractional stable noise （LFSN） and the alpha stable random variables are provided. Model construction and the quantitative comparisons with fractional Brown motion （FBM） and real traffic are also examined. Open problems and future directions are also given with thoughtful discussions.展开更多
对DVB Over IP应用来说,如何传送用可变比特率(VBR)压缩的MPEG-2传输流格式的视频是一个重要的问题。其中以传统的恒定速率(CBR)方式传送VBR视频时,接收端需要较大的缓存和开始延时时间;而另一种新的采用PCR协助的恒定速率(PCBR)传送方...对DVB Over IP应用来说,如何传送用可变比特率(VBR)压缩的MPEG-2传输流格式的视频是一个重要的问题。其中以传统的恒定速率(CBR)方式传送VBR视频时,接收端需要较大的缓存和开始延时时间;而另一种新的采用PCR协助的恒定速率(PCBR)传送方式,则是以较高的传输速率和以牺牲码率的稳定性来减少缓存需求。为了平衡传输速率和接收端缓存需求,在PCBR基础上,提出了一种称为IPCBR的改进的视频流传送方法。通过实验证明,该新方法与传统的CBR传送方式相比,不仅可降低缓存需求,而且与PCBR方式相比,又具有较高的稳定性和带宽利用率,并克服了PCBR丢包率较高的问题。同时由于该算法特别针对DVB Over IP,具有较强的实用性,且有利于Internet TV业务拓展。展开更多
基金Project supported by the Hi-Tech Research and Development Pro-gram (863) of China (No. 2003AA103810) and the National NaturalScience Foundation of China (No. 60332030)
文摘Transmission of variable bit rate (VBR) video, because of the burstiness of VBR video traffic, has high fluctuation in bandwidth requirement. Traffic smoothing algorithm is very efficient in reducing burstiness of the VBR video stream by trans- mitting data in a series of fixed rates. We propose in this paper a novel segment-based bandwidth allocation algorithm which dynamically adjusts the segmentation boundary and changes the transmission rate at the latest possible point so that the video segment will be extended as long as possible and the number of rate changes can be as small as possible while keeping the peak rate low. Simulation results showed that our approach has small bandwidth requirement, high bandwidth utilization and low computation cost.
文摘The alpha stable self-similar stochastic process has been proved an effective model for high variable data traffic. A deep insight into some special issues and considerations on use of the process to model aggregated VBR video traffic is made. Different methods to estimate stability parameter a and self-similar parameter H are compared. Processes to generate the linear fractional stable noise （LFSN） and the alpha stable random variables are provided. Model construction and the quantitative comparisons with fractional Brown motion （FBM） and real traffic are also examined. Open problems and future directions are also given with thoughtful discussions.
基金Supported by National Natural Science Foundation of China（60434030,60673178,and 60472076） and National Basic Research Program of China（973 Program）（2007CB307106）
文摘对DVB Over IP应用来说,如何传送用可变比特率(VBR)压缩的MPEG-2传输流格式的视频是一个重要的问题。其中以传统的恒定速率(CBR)方式传送VBR视频时,接收端需要较大的缓存和开始延时时间;而另一种新的采用PCR协助的恒定速率(PCBR)传送方式,则是以较高的传输速率和以牺牲码率的稳定性来减少缓存需求。为了平衡传输速率和接收端缓存需求,在PCBR基础上,提出了一种称为IPCBR的改进的视频流传送方法。通过实验证明,该新方法与传统的CBR传送方式相比,不仅可降低缓存需求,而且与PCBR方式相比,又具有较高的稳定性和带宽利用率,并克服了PCBR丢包率较高的问题。同时由于该算法特别针对DVB Over IP,具有较强的实用性,且有利于Internet TV业务拓展。
