1. Wavelet-Based VBR Video Traffic Smoothing Dejian Ye, J. Cam Barker, Zixiang Xiong, and Wenwu Zhu IEEE Trans. Multimedia, Aug. 2004

2. Outline VBR video transmission Smoothing algorithms MVBA (minimum variance) MCBA (minimum changes) PCRTT (piecewise constant-rate) WTS (wavelet-based traffic smoothing) Smoothing at multiple resolution Low computational complexity Performance evaluation

3. Typical video distribution scenario

4. VBR: single traffic flow

5. VBR: aggregated traffic flow From server to client: link 3 link 2 link 1

6. Buffer constraints

7. MVBA (minimum variance bandwidth allocation) U L

8. MCBA (minimum changes bandwidth allocation) U L

9. PCRTT (piecewise constant-rate transmission and transport) Divide the video stream into segments to create a transmission schedule. Each segment corresponds to one rate in the transmission schedule. (set the transmission rate to the average frame size for each segment) Raise the transmission schedule to avoid client buffer underflow. Force a rate change after every segment.

10. Seg 5Seg 4Seg 3Seg 2Seg 1 PCRTT L

11. WTS PCRTT works well for both single and aggregated flows. WTS is based on PCRTT. Motivations: Smooth aggregated flows. (?) Client buffers can be heterogeneous. (difficult to schedule transmission)

12. Possible schedules in WTS

13. Binary tree T max Has enough buffer? u j+1, 2k u j+2, 4k+2 u j+2, 4k+3

14. Multiple-flow clients and movies

15. #flow: #rate changes

16. #flow: rate variation

17. #flow: the min time between two adjacent rate changes

18. #flow: peak rate

19. Buffer size: #rate changes

20. Buffer size: rate variance

21. Buffer size: the min #frames between two adjacent rate changes

22. Buffer size: peak rate