An Overlay Multicast Infrastructure for Live/Stored Video Streaming

Visual Communication Laboratory

Department of Computer Science

National Tsing Hua University

Outline Live video broadcasting

Typical service model Limitations

Our goals Overlay multicast infrastructure

Our previous works Multicast video streaming Peer-to-peer search & delivery Scalable video coding

Live Video Broadcasting Techniques

Live video encoding Multicast delivery

Commercial products Windows Media Services (Microsoft) Real System Server (Real) QuickTime Streaming Server (Apple)

Service Architecture

Encoder

Stream Server(VOD)

Storage

Internet

(VOD)

(Live Broadcast)

Stream Server(Live)

Multicast Routing Tree

Client A(10:00)

Client B(10:00)

Client C(10:00)Client D

(10:00)

Video Server

Common Solution: Prefix Caching

41 2 3

Prefix cacheVideo Server

1, 2, 3, 4

5, 6, 7, …

Permanently cache the front part of the video. Clients request before (the start time + the length of

the prefix) can see the entire video program.

C1

Multicast + Prefix Caching

Client A(10:00)

Client B(10:00)

Client C(10:00)

Video Server

Client D(10:05)

5 min

5 min

store the first 5 min (10:05)

queue the stream

(10:10) read data from the buffer

Limitations Must know the video source in advance.

Need router support. (IP multicast)

Cannot pass through firewall/NAT.

Users arrive after the system startup time cannot view the front part of the video. Prefix caching is not perfect.

Scenario: Request & Playback User input

Service mode (live/on-demand) Video attributes

Peer-to-peer search Streaming

Overlay multicast Payment (?)

By service mode (VOD > live) (from server > from p2p)

By video (popular > unpopular) (bit rate) By search method (advanced > basic)

Request flow

EPG

meta datapeer 1

peer 0

peer 2

Search

P2P

Player

input : service modequery rules

peer 3

peer 4

distributed queryinit multicastvideo stream

Topics in this project Overlay multicast

Peer-to-peer infrastructure Performance optimization

Two-mode multicasting Live broadcasting (real-time) On-demand streaming (see the entire

video)

Advanced Topics (?) Advanced electronic program guide

Intelligent search Personal profile Ambiguous keyword search Melody / scene search Distributed / continuous query Matchmaker (?)

Meta datas Creation/collection/distribution Format (?) (object-based?)

Our Previous Works On-Demand Multicast Streaming

Delivery Platform

Technology and Systems Peer-to-Peer Streaming Video (Directory

Search) Proxy-based Streaming Video

Multicast streaming platform for layered videos

10:00

10:00

10:00

10:00

10:00

10:00

10:04

10:01

10:02

10:03

10:02

On-Demand Multicast Communications

10:00

10:00

10:00

10:02

10:03

10:04

Source

Node with timing control

Interval Caching

Caching buffer

4, 3, 2, 1

Video Server

14 3 2 25 4 3

Cache a sliding interval of the video.

C1 10:00

C2 10:04

1

15, 4, 3, 2, 1

2, 1

Timing Control Mechanism

Player B

10:00

Player C

10:0310:00

34567 To player D, 10:05

To player B, 10:00

2, 1

7, 6, 5, 4, 3, 2, 1

Player D10:05

4, 3, 2, 1To player C, 10:03

On-Demand Multicast Routing

source

10:00

Network

Constructing an on-demand multicast tree1. find a routing path2. allocate buffers to generate path delay

10:0610:08

10:02

10:03

10:06

Playback (with Directory Server)

directory server

module.exe

IE

Client

WWW

Proxy

Source

module.exe

1

2

3

4

5

6

7

8

Playback (Peer-to-Peer)

source

… … …client

Pi

Pj

Ps

10:00

10:02

1. find a source2. find a routing

path3. allocate buffers

P2P v.s. Proxy Platform

IP Networks

Virtual File System(Media Query)

(Information Delivery)

Video Streaming(HTTP)

Media Player

QoSIP Networks

CacheReplacementNetwork Mgmt.

Proxy-Based

Peer-to-Peer

Selection &Chaining

Proxy

Video Streaming(HTTP)

Media Player

Mgmt. GUINetwork Mgmt.QoS Reservation

ProxyProtocolReplacementChaining

Fault Handling

Source

11:30

11:40

11:43

11:44

11:33

11:34

11:35

11:30

11:40

11:32

One of the clients faultsAuto reconfiguration

Scalable Video Coding

Heterogeneous Network Bandwidth

Server

1.5 Mbps

0.8 Mbps

1.5 Mbps

0.8 Mbps

0.7 Mbps

aggregated stream

0.8 Mbps

low quality

1.5 Mbps

High quality

Bottleneck = 0.7 Mbps

End-to-end Layer Subscription with Bandwidth Constraint

…

Layer 1

Layer 2

Layer L

Scheduler Lossy Channel

Sender

Decoder with Error Concealment

Receiver

Demo System

GUI (Media Player)

filenamenumber of layers

GUI (Management)