1. Periodic Broadcasting with VBR- Encoded Video Despina Saparilla, Keith W. Ross and Martin Reisslein (1999) Prepared by Nera Liu Wing Chun

2. Presentation Outline Introduction Related Works & Motivation Near VoD with VBR Encoded Video Conclusion

3. Traditional Video-on-Demand (VoD) System (True VoD) – It is unicast-based system. – As every user requires a dedicated channel (resources including server and network bandwidth etc.), it is not scalable enough. Introduction

4. Related Works Close-loop architectures – It schedules video streams dynamically according to user arrival pattern. – For example: Patching Open-loop architectures – It has a fixed schedules for all video streaming irrespective of the user arrival. – For example: NVoD K. A. Hua, Y. Cai, and S. Sheu, “Patching: A Multicast Technique for True Video-on-Demand Services,” Proceedings of the 6 th International Conference on Multimedia, Sep 1998, pp. 191-200.

5. Motivation However, most of the architectures are based on the assumption of constant bit-rate video. With the fact that the average bit rate for CBR video is typically 2 times or more the average bit rate of VBR video of the same perceptional visual quality. VBR video streaming has a potential to increase the system efficiency.

6. Near VoD with VBR Encoded Video Pyramid Broadcasting Scheme – Video is partitioned into video segment with L i+1 =  L i – Max Startup Latency = L 0 – Client Access Bandwidth = 2b, b is the video bit-rate S. Viswanathan and T. Imielinski, “Metropolitan Area Video-on-Demand Service Using Pyramid Broadcasting,” IEEE Multimedia Systems, vol. 4, 1996, pp. 197-208. L0L0 L1L1 L2L2 time Channels Client arrival L0L0 L0L0 L0L0 L0L0 L0L0 L0L0 L0L0 L1L1 L1L1 L1L1 L2L2 L0L0 L1L1 L2L2 …. The challenge here is to guarantee the continuous playback.

7. Near VoD with VBR Encoded Video Pyramid Broadcasting Scheme – Video is partitioned into video segment with L i+1 =  L i – Max Startup Latency = L 0 – Client Access Bandwidth = 2b, b is the video bit-rate Proposed Scheme – Video is partitioned into video segment with L i+1 = 2 L i – Max Startup Latency = L 0 – Client Access Bandwidth = qb, b is the video bit-rate

8. System Model The system has M videos and each video is divided according to scheme of Pyramid Broadcasting. x i (m) represents the i th video sequence of m th video. y t (m,k) represents the video sequence of m th video multicasting over the k th channel at time t.

9. System Model Therefore, the aggregated bandwidth at time t defined is The Server bandwidth is C Mbps The probability of loss

10. Simulation Settings The total number of video, M = 10. The average bit-rate of the video is 2 Mbps.

11. Bufferless Statistical Multiplexing

12. Bufferless Statistical Multiplexing with GoP Smoothing

13. K=7 K=6

14. Buffered Statistical Multiplexing K=6 K=7 K=6

15. VBR and CBR Comparison The bit rate of CBR video is 1.8 times of the VBR video. (For example is the bit rate of VBR is 2Mbps, the CBR is 3.6Mbps)

16. Conclusion This scheme proposed a modified version of Pyramid Broadcasting scheme to support VBR video streaming.

17. Q & A