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A P2P On-Demand Video Streaming System with Multiple Description Coding

This paper presents a P2P video streaming system that uses multiple description coding to improve reliability and scalability. The system distributes video descriptions across multiple peers, ensuring resilience to peer failures. The benefits include low bandwidth costs, easy deployment, and prevention of illegal access to videos.

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A P2P On-Demand Video Streaming System with Multiple Description Coding

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  1. A P2P On-Demand Video Streaming System with Multiple Description Coding Yanming Shen, Xiaofeng Xu, Shivendra Panwar, Keith Ross, Yao Wang Polytechnic University

  2. Introduction • Media content forms a significant fraction of Internet traffic. -Problem: live streaming to a large audience in the wide- area Internet -Standard solution: Infrastructure-based 1. Bandwidth costs from a central source can be costly 2. Single source may not be able to provide full bandwidth • P2P streaming is attractive -Self scaling -Easy to deploy, low cost • Problem: Unreliable peers • Resilience to peer failures, departures - multiple description coding

  3. System Overview • Videos are encoded into multiple descriptions. • Place each description on a different server. • When a client wants to see a video, multiple peers act as servers, each sending a different description of the video to the client. • When a server peer disconnects in the middle of a streaming session, the system searches for a replacement peer that is storing the same video description and has sufficient uplink bandwidth.

  4. System Overview • Consider a star network architecture. • Initially, node 4 receives descriptions from nodes 2 and 3. • Node 5 receives from nodes 1 and 4. • Then node 2 disconnects, • And the system recovers by assigning node 6 as a replacement. While locating and establishing a replacement, visual quality at node 4 is degraded. We use a fat pipe to indicate the downlink of each node, and a thin pipe to illustrate the uplink of each node. • Generally, a node can function as a client only (e.g., node 5); • A server only (e.g., node 1); • Or simultaneously as a server and a client (e.g., node 4). Server & Client Server Client

  5. Benefits of Multiple Descriptions • When a server peer disconnects, client only loses a single description • Each description has a low bit-rate. • A natural fit to current Internet access architecture: Asymmetric upstream (low) and downstream (high) bandwidths, ample bandwidth in the core Internet • Spread the load over the serving peers • Multiplexing gains in the core Internet • Prevent illegal access to the video

  6. System Overview • Five interacting components of system design: • Video Coding; • Description Placement; • Admission Control; • Server Selection; • Description Delivery.

  7. Design Criterion • Performance measures • Acceptance probability: the likelihood the system will locate the necessary descriptions and establish a session. • Video quality: the visual quality of the session, from start to finish.

  8. MD-FEC Video Coding • Divide the stream into Group Of Frames (GOF). • Each GOF is partitioned into M layers. • kth layer is further divided into k equal-length groups. • Reed-Solomon (RS) code is applied to k groups to yield M groups. D0 D1 Distortion D2 Dm DM … … R1 R2 Rm RM R0 R1 R2 Rm RM … … m M 1 2 … … (RM-RM-1)/M R1 (R2-R1)/2 (Rm-Rm-1)/m … … FEC (R2-R1)/2 (Rm-Rm-1)/m (RM-RM-1)/M … … (RM-RM-1)/M FEC FEC FEC … …

  9. MD-FEC Video Coding • Pm denotes the probability of receiving m out of M descriptions. • Dm(R1,…,RM) denotes the distortion when m descriptions are received for layer partition (R1,…,RM). • Expected distortion • The MD-FEC optimization problem can be formulated for a given M, r, and P as follows: determine the optimal layer partition (R1,…,RM) for

  10. Simulation Setting • Video data -Video coded into scalable bit stream using the MPEG-4 FGS codec -Generate M descriptions using the MD-FEC method, M from 4 to 32. -total rate: 512 kbps or 576 kbps. • Network setting -Fixed uplink bandwidth (250 kbps) and storage (230 MBytes) -Each node alternates between “connect” and “disconnect” status. • Video placement -each node stores at most one description for a particular video. • Admission control -Parameter Qmax: If the total number of sessions in the network is greater than Qmax, then the new requests are blocked.

  11. Simulation Results • System performance generally improves as the number of descriptions (M) for the videos increases.

  12. Simulation Results • Video quality decreases as Qmax increases. • A lower total rate might give a better video quality.

  13. Conclusion • Peer-to-peer networking with multiple description video coding is a promising technique for an on-demand video streaming service. • Video quality can be maintained in the face of peer departures. • Increasing the number of descriptions can improve the system performance. • Future work: layered coding

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