1. Layered Coding & Congestion Adaptation in a Multicast Scalable Video Delivery System Yuming Jiang Q2S, NTNU Q2S Friday Colloquium, February 6, 2004

2. Outline Introdution The System Layered Multicast Embedded Zerotree Wavelet (EZW) Coding Color-Resolution Layered Coding Tri-zerotrees (TRI-ZTR) Coding Color-Resolution Layering Layer Prioritization & Automatic Congestion Adaptation Layered Multicast & Layer Prioritization Congestion Adaptation at Client Congestion Handling at Router Summary Some Issues for Discussion

3. Real-Time Video Delivery System

4. Layered Multicast

5. Embedded Zerotree Wavelet Coding

6. Tri-Zerotree Coding (1)

7. Tri-Zerotree Coding (2)

8. Color-Resolution Layering (1) Gray component Y U V Color components BLEL1 EL2 EL3EL4 EL5

9. Color-Resolution Layering (2)

10. Layered Multicast & Layer Prioritization ResolutionGrayColor 1/16BL+EL3 1/4BL+EL1+EL3+EL4 FullBL+EL1+EL2+EL3+EL4+EL5 LayerMulticast BLGroup 1 EL1Group 2 EL2Group 3 EL3Group 4 EL4Group 5 EL5Group 6 Priority High Low

11. Congestion Adaptation at Client Manual Congestion Adaptation When congestion happens, the client notices the degradation of video quality and manually changes/decreases its subscriptions to layers. Automatic Congestion Adaptation The client automatically increase or decrease its subscriptions to layers based on the following layer-add and layer-drop policies: Increase subscription if the probed loss rate is less than T_add; Decrease subcription if the probed loss rate is larger than T_drop. T_add=max_add-δ_add x l T_drop=max_drop-δ_drop x l l (=0,..., 5): the number of ELs subscribed max_add: maximum loss rate beyond which no new layer is added max_drop: maximum loss rate beyond which all layers should be dropped δ_add/ δ_drop: separation between T_add/T_drop of adjacent layers T_add and T_drop values are affected by the setting of the congestion handling scheme implemented at network router.

12. Congestion Adaptation at Router Adopt DiffServ to provide isolation from best effort traffic. Implement Assured Forwarding to support multiple drop precedences. Use multi-level RED (random early detection) for buffer management when congestion happens. Two-level RED For Enhancement Layers For Base Layer Packet drop prob. Buffer occupancy 1.0 Max_p_el Max_p_bl

13. Sample Client Displays Full size QCIF color1/4 size QCIF monochrome

14. Summary Introduced a Multicast Scalable Video Delivery System Presented a Color-Resolution Layered Coding Scheme Briefed an Automatic Congestion Adaptation Approach

15. Issues for Further Research How to packetize video stream and what is its effect on received video quality in the case of packet loss? How to prioritize layers? How many priority levels are needed and how many levels are sufficient? What is the effect of each layer loss and what is the tolerable loss rate? How to design a network scheme to satisfy the loss requirement and what is the effect of its parameter setting? How to design a congestion adaptation policy at client and what is its effect on the network and final perceived video quality? What is the tolerable delay for each priority layer? How to design network schemes to satisfy the delay requirement? What are the corresponding requirements for other applications such as telephony and conferencing? What are the corresponding requirements for other coding schemes, particularly those with inter-frame coding? etc.

16. Coordinated Quality of Service for End-to-End Content Delivery Raw content Compressed content Network content Received content Perceived content Content Provider Content Consumer Network Coding Storing Packetizing Layering Mapping Delay guarant. Layer diff. Cons. diff. Buffering. Reordering Adapting Rendering Decoing End-To-End Content Delivery Loss guarant. 2004 IEEE Workshop on Coordinated QoS in Distributed Systems (http://www.sp.edu.sg/icon2004/)