Efficient Sub-stream Encoding and Transmission for P2P Video on Demand 1 Efficient Sub-Stream Encoding and Transmission for P2P Video on Demand Zhengye Liu Yanming Shen Shivendra S. Panwar Keith W. Ross Yao Wang Polytechnic University, Brooklyn, NY, USA

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand 2 Outline Motivation P2P VoD system Sub-stream encoding and transmission Simulations Conclusion

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand 3 Motivation Video-on-demand services –Youtube, MSN video, google video,… –Content distribution networks (CDNs) P2P live streaming systems –PPLive, PPStream, UUSee, Coolstreaming,… –Support thousands of users simultaneously

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand 4 P2P VoD System Multiple video architecture –Extension of CDNs: Peers act as video servers –Contribute storage in addition to bandwidth –Help each other with stored videos

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand 5 Proposed System with Multiple Sub-Streams In this illustration, two simultaneous streaming sessions are requested from nodes 4 and 5. The system initially selects nodes 2 and 3 to serve node 4’s request, and selects nodes 4 and 1 to serve node 5’s request. After Node 2 goes down, the system finds node 6 as a replacement

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand 6 Benefit of Using Layered Coding/MDC Adaptive to the long-term bandwidth fluctuation due to peer churn –Uplink bandwidth fluctuation –Received video quality adapts to the available uplink bandwidth Robust to peer failure/disconnection –One supplier failure only affects one/several sub- stream(s) –Video quality will not be impaired seriously

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand 7 Multi-Stream Coding Schemes (a) Layered coding(b) MDC (c) Ideal scheme –Compare schemes (a), (b) –Design (c)

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand 8 Push-Pull Delivery with Layered Coding Store all layers of a video Push-pull for layer delivery Storage consumed for one video: RM

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand 9 The Ideal Scheme should consume minimum storage The Ideal Scheme should consume minimum storage Can we reduce the consumed storage? The minimum storage: R+R/2+,…,+R/M≈ R ln(M)

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand 10 RS Coding RS (8,2) coding for Layer 2 Any two received chunks can recover the original two chunks

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand 11 RS Coding Instead of Replicating RS (8,k) coding, k=1,2,3,4

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand 12 Redundancy-Free Transmission Based on Push-Pull Architecture A receiver schedules the chunks that should be delivered (Pull) A supplier pushes the chunks based on the schedule (Push) R

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand 13 Features of Proposed Scheme Ideal Scheme –Equal importance (like MDC) –Redundancy free transmission (like Layered coding) Minimum storage consumed –R ln(M) vs. RM M=4, 2.08R vs. 4R, save about 50% M=32, 3.47R vs. 32R, save about 89% Since a peer needs to store fewer substreams: save server bandwidth

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand Simulations Setting –3000 peers, different uplink bandwidth –30 videos, different popularity (Zipf distribution with parameter 0.27) Simulate two video sequences –Foreman: low rate –Mobile: high rate Compare SLRS, Layered Coding, MD-FEC, RFMD Performance metrics –Discontinuity: number of undecodable GOPs/Total number of GOPs –PSNR 14

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand Simulation Results 15 Discontinuity of different schemes vs. number of active users under the “Foreman” sequence PSNR of different schemes vs. number of active users under the “Foreman” sequence

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand Simulation Results 16 Discontinuity of different schemes vs. number of active users under the “Mobile” sequence PSNR of different schemes vs. number of active users under the “Mobile” sequence

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand 17 Conclusion Propose a redundancy-free transmission scheme based on a push-pull architecture RFMD –Advantages All substreams have equal importance: graceful quality degradation Only the source bits are transmitted: no transmission redundancy Coding instead replication: any combination of M or fewer substreams can be used in reconstructing video –Additional cost: Feedback from the client to each supplying peer: feasible in typical P2P VoD applications

Efficient Sub-stream Encoding and Transmission for P2P Video on Demand 18 Thanks!