1. Reliable and Smooth Fine Granular Scalable Video Streaming Zhibo Chen Yun He 2002 IEEE Region 10 Conference on Computer, Communications, Control and Power Engineering

2. Outline Introduction Server Architecture Quality Weighted Bit Allocation Quality Weighted Error Control Simulation Conclusion

3. Introduction Key of Video Streaming –Smooth Playback –Retransmission-based error control scheme Tradeoff Problem –Prefetch a new packet –Retransmit a lost packet

4. Introduction FGS Stream –Base Layer (CBR) –Enhance Layer BaseEnhance

5. Introduction Quality Weighted Bit Allocation (QWBA) –Achieve smooth quality of playback. Quality Weighted Error Control (QWEC) –Loss protection. –Tradeoff between prefetching and retransmission.

6. Server Architecture R b ≤ R min

7. QWBA Minimize the variance of the quality of the decoded video sequence, subject to a bit rate constraint on the enhance layer N : denote the number of frames in the preteching interval T R Ei : denote the bits allocated for the enhance layer in the i th frame R T = R B + R E

8. QWBA Priori Information –BPSNR i –R Ei is in proportion to ∆PSNR i

9. QWBA

10. P : Sum of those p i with the constraint p i ≥ 0 N’ : the number of frames with p i ≥ 0, so N ≥ N

11. QWEC Enhance layer needs to be divided into several packets Definition of enhance layer packet’s priority –Layer difference –Quality difference

12. QWEC E num : sequence number of an enhance layer packet of a given frame (ex. 1, 2, 3, …N ) The lower V prio is the higher the priority of that packet V prio of all base layer packets : 0

13. Comparison Forward error correction (FEC) –Increase bandwidth consumption –Lower performance on burst channel –Addition computation load

14. Simulation QWBA QWEC Packet loss rate : 10%

15. Simulation

16. Conclusion QWBA manipulates the enhance layer stream according the PSNR variation of base layer based a solid theoretical analysis to achieve a smooth playback quality. QWEC gives a packet’s priority definition considering both layer difference and quality difference.