1 p2p layer streaming for heterogeneous networks in ppsp k. wu, z. lei, d. chiu kent kangheng wu...

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P2P Layer Streaming for Heterogeneous Networks in PPSP

K. Wu, Z. Lei, D. Chiu

Kent Kangheng Wu9/11/2010

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Heterogeneous Networks

1) Scenario• PCs, set-top boxes and mobile

devices may all need to access and provide service for the same content.

2) Problems• Use multiple versions of video

content (each encoded at different resolution or visual quality).

• Peers in different versions will not help each other.

• The overall video quality received will not be optimal.

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An Example

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P2P Layer Streaming

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Layer Video1) Single layer Video

• All peers receive the same video quality

2) Layered video• A video is encoded into several layers• More layers introduce better video quality• Nested dependence between layers• A higher layer can be decoded only if all the lower layers are

available

3) Higher upload contribution results in better received video quality

L4

L3

L2

L1

L2

L1

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Multiple Description Coding

1) Video encoding/decoding technology• Video content is encoded into several descriptions• Each description can be decoded independently• Even receiver only receives one description, the video is

displayed with low quality• The more descriptions received, the better video quality• Compared with layered streaming, multiple description has

lower coding efficiency and worse performance.

encoding

MDCVideocontent

decoding

MDC

# of description

Vid

eo

qu

ality

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Message Flows

1) PUT-LAYER (Put Layer Information) into Tracker

2) GET-LAYER (Get Layer Information) from Tracker

3) PUT-CHUNK (Put Chunk Information) into Tracker

4) GET-PEERLIST (Peer Selection)

5) LAYER-CHANGE (Layer Change)

6) STATISTICS

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Open issues

1) Data Scheduling• Different strategy with single layer streaming

2) System Performance Metrics• Throughput and Delay• Layer Delivery Ratio• Useless Packets Ratio• Jitter Prevention

3) User Performance Metrics• Start-up Delay• Playback Continuity• Playback Delay

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End of PresentationThank you. Do you have any questions?

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