1 / 21

Video Staging: A Proxy-Server-Based Approach to End-to-End Video Delivery over Wide-Area Networks

Video Staging: A Proxy-Server-Based Approach to End-to-End Video Delivery over Wide-Area Networks. Zhi-Li Zhang, Yuewei Wang, David H. C. Du, Dongli Su IEEE/ACM TRANSACTIONS ON NETWORKING, AUGUEST 2000. Outline. Introduction Video Staging: A Single Video Case without Smoothing

kordell
Télécharger la présentation

Video Staging: A Proxy-Server-Based Approach to End-to-End Video Delivery over Wide-Area Networks

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Video Staging: A Proxy-Server-Based Approach to End-to-End Video Delivery over Wide-Area Networks Zhi-Li Zhang, Yuewei Wang, David H. C. Du, Dongli Su IEEE/ACM TRANSACTIONS ON NETWORKING, AUGUEST 2000

  2. Outline • Introduction • Video Staging: A Single Video Case • without Smoothing • with Smoothing • Empirical Evaluation • Video Staging: Multiple Video Case • Staging Hot Video Only(SHVO) • Largest Bandwidth Reduction Ratio First(LBRRF) • Empirical Evaluation • Conclusion

  3. Introduction • Video Staging • Reduce the bandwidth requirement in the Backbone WAN • Prefetch a predetermined amount of video data and store them a priori at proxy servers • Only part of a video stream is retrieved directly from the central video server across the backbone WAN

  4. Video Staging(cont.) • Trading the disk bandwidth of a proxy server for the backbone WAN bandwidth • The video data are staged at the proxy server on a fairly long period of time instead of caching in and purged out dynamically

  5. Video Staging:A Single Video Case • Video Staging Without Smoothing i : the index of a video Ni: total number of frames F : frame period sij : the size of jth frame j = 1,…, Ni Pi : the peak rate of video i Pi = (max1<=j<=Nisij) /F Ci : cut-off rate 0 <= Ci <=Pi*F = max1<=j<=Nisij

  6. Video Staging Without Smoothing • The upper part consists of a sequence of partial frames with size sij ,u = (sij - Ci )+ j = 1,…, Ni where x+ = max{x,0} • The lower part consists of a sequence of partial frames with size sij ,l = sij - (sij - Ci )+j = 1,…, Ni

  7. Video Staging Without Smoothing • The smaller Ci is,the more video data is staged at a proxy server. • As Ci decreases, the lower part of the video becomes less bursty, and eventually approaches to an essentially CBR stream. • The backbone WAN bandwidth requirement from Pi to Ti = Ci / F • The upper part of the video consume Di = (max1<=j<=Nisij,u) / F disk bandwidth • Bandwidth reduction ratio Ri = (Pi -Ti) / Di

  8. Video Staging With Smoothing • Cut-Off After Smoothing (CAS) si~j : referred to as smoothed framessize Pi : the peak rate of smoothed stream Ci : cut-off rate 0 <= Ci <=Pi*F = max1<=j<=Nisi~j Ti = Ci / F amount of backbone WAN bandwidth is reserved Di= (max1<=j<=Nisi~j,u) / F amount of disk bandwidth is required in the worst case

  9. Video Staging With Smoothing • Cut-Off Before Smoothing • Smoothing on the Lower Part(SOLP) Ti = Pi =(max1<=j<=Nisi~j,l) / F • Smoothing on the Upper Part(SOUP) • Reduce the disk bandwidth required • Smoothing on the Upper and Lower Parts(SOLP) Bl = B * (Ci / Pi * F) Bu = B * (1- (Ci / Pi * F))

  10. Proxy server disk resource requirements for a single stream

  11. Resource requirements for a single stream

  12. Ratio of backbone WAN bandwidth reduction to proxy server disk bandwidth

  13. Video Staging: Multiple Video Case • Disk bandwidth • Total amount of storage space • The number of expected concurrent accesses • Total reduction in the backbone WAN bandwidth is maximized • Disk bandwidth constraint • Disk storage constraint

  14. Staging Hot Video Only (SHVO) • Regard the user access pattern as the most important factor in determining which video to stage at the proxy server. • The videos are ordered with respect to their relative “popularity” • The number of k hottest videos that can be staged at the proxy server is determined • Either a video is entirely staged at the proxy server or not at all

  15. Largest Bandwidth Reduction Ratio First (LBRRF) • Use the backbone WAN bandwidth reduction ratio Ri in determining which video and what percentage of it to be staged • The burstier video and the video with larger number of concurrent accesses is more likely to have a higher Ri • CPi percentage of video i is staged at the proxy server • The algorithm starts with CPi = 0 for all videos and iterates by incrementing CPi by P amount at each step.

  16. Impact of proxy server disk resources:clients have no smoothing buffer

  17. Impact of proxy server disk resources:clients have 64KB smoothing buffer

  18. Conclusion • A major objective of our approach is to reduce the backbone WAN bandwidth requirement. • We have designed various video staging methods and evaluated their effectiveness in trading the disk bandwidth of a proxy server for the backbone WAN bandwidth. • The proposed proxy-server-based video staging technique provides a cost-effective and scalable solution to the problem of the end-to-end video delivery over WANs.

More Related