Acquisition of Scalability at Large Scale Video Conference

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Acquisition of Scalability at Large Scale Video
Conference

• Matsuoka Lab.
• Hiroyuki Komatsu
• 2002-02-08

http//taiyaki.org/
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What is Acquisition of Scalability on Video
Conference?
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I Want to Layout These Numerous Windows
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Like This!
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Large Scale Video Conference is required ?
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SCGlobal

• Large scale video conference in fall 2001
• 12 Countries, 77 nodes
• AccessGrid for the large scale video conferencing
  system

• AccessGrid
• Employs
• Multicast
• Vic(video), Rat(audio)

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Yet Another Scalability ?

• Network Scalability

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Problems for Large Scale Video Conference
(Network)

• Large scale video conference requires Multicast
  protocol for connecting P2P
• Order of server-side traffic is O(n2), when using
  an usual server-client style with MCU
• Order of multicast traffic is O(n)
• Multicast Protocol is not well in use
• Not supported by routers
• Small demands
• Requires enough knowledge

Setting up multicast or alternatives is required
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Related Work

• mTunnel 97 Pernes et al.
• Web page based interface
• Tunnels each multicast connections
• Multicast on Dial-up 98 Kuhmunch
• Server translates multicast packets into unicast
• The client side requires no multicast environment

• Can not assume network multicast environment
• at the client side
• Multiple client machines consume extra bandwidth

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Problems for Large Scale Video Conference
(User-Interface)

• Too many video windows
• Difficult to know who is speaking and whom speak
  to
• Force users to re-layout video windows
• Simple layouting unsolve the difficulty

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Too Many Windows
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Simple Layouting Unsolve the Difficulty
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Problems for Large Scale Video Conference
(User-Interface)

• Too many video windows
• Difficult to know who is speaking and whom speak
  to
• Force users to re-layout video windows
• Simple layouting unsolve the difficulty

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Related Work (1/2)

• TELEP 00 Gavin
• Tele-lecture system
• Tiled layout for audience windows
• Forwards important windows
• Clear division between a speaker and audiences

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Related Work (2/2)

• ChatScape 00 Ayatsuka et al.
• Snaps a photo synchronizing with speech
• Displays photos in order like cartoons
• Easy to understand the context
• Supposesa text chat

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Objective

• To acquire network scalability
• Setup multicast dynamically for connecting P2P
  without specific servers like MCU
• To acquire User-interface Scalability
• Layout windows based on the context of video
  conference

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Acquire Network Scalability
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Multicast Tunneling
Local Network

• Sets up multicast environment
• Tunnels against unicast environment
• Makes a whole local network multicast environment
  with a multicast router

Multicast Router
Tunneling
Multicast
Multicast Router
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Dmconnect
Local Network

• Sets up multicast dynamically
• Able to set up at where go out and mobile network
• Server-Client style
• Employs GRE tunneling protocol, PIM-SM routers
• Allow users to set up without login the server

Dmconnect Client
GRE Tunneling
Multicast
Dmconnect Server
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Connection by Dmconnect

• Run dmconnect command with an argument of server
  in a client
• dmconnect dmserver.is.titech.ac.jp
• Server returns to a client sub-network address
  space for tunneling
• After tunneling
• Runs a multicast router in the client machine
• Changes configure for multicast router in the
  server machine

Dmconnect just sets up multicast environment
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Acquire User-Interface Scalability
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Vansyn??

• Layouts windows based on the context
• Creates a dialog model
• Guesses a status of the conversation
• Changes windows layout based on the guessed
  status
• Included in existing video conferencing systems
• Takes over existing systems
• Included in a new system
• Customized by system developers for layout
  algorithm
• Uses object oriented script language Ruby
• Hides an inner structure of a system

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Dialog Model

• Makes a model of dialog
• Creates a status of conversation by grouping
• Conversation group
• Speaker group
• Audience group
• Environment group
• (E.g.. materials)
• Apathy group
• Changes the status by degrees
• Gives each nodes in groups a priority

Node
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Status of Conversation Example

• Example for layout
• A,F the largest display
• B normal display
• C,D,E display considering free space

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Changing a Status of Conversation Example

• Where after As speech C asks B
• C moves speaker group
• B takes more priority

Conversation Group
Speaker Group
Audience Group
E
A
C
C
B
D
Environment Group
F

• Example for layout
• B,C Large and closed display

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Changing a Status of Conversation

• Gets events of video conference
• Event manager translates events of video
  conference into events of Vansyn
• Changes a status of conversation based on the
  events
• Chairperson changes a status

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Window Layout Based on Statuses of Conversation

• Decides window layout based on the status of
  conversation
• Layout manager decides the layout
• Layouts windows actually
• Window manager calls inner functions of the
  system from Vansyns APIs

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Main Loop with Statuses of Conversation and
Layout Windows

• Gets evens of video conference
• Creates a status of conversation
• Decides windows layout based on the status of
  conversation
• Layouts windows

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Functions Provided by Vansyn

• Event Manager
• Window Manager
• APIs of Dialog-Model
• Templates of Chairperson and Layout Manager

System developers make Chairperson and Layout
Manager
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Window Manager

• Gets current windows layout
• Gets free spaces for display
• Changes windows layout

newWin
?
spaceList newWin.spaces
Table Methods for Window Manager (a part)
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Event Manager

• Gets events of nodes (E.g.. Changing statuses
  like speech and/or motion)
• Stores event data
• Answers about queries to the events

eventA new VansynEvent(voice,
motion) time eventManager.lastEventTime(e
ventA) if (time gt threshold) then else
end
Table Methods of Event Manager (a part)
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Vansyn into AccessGrid
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Embedding Vansyn
Vansyn

• Event Manager gets events of Vic and Rat
• Window Manager relates Vic
• Prototype of Chairperson and Layout Manager

Conversation Status
Chair-person
Layout Manager
Event Manager
Window Manager
AccessGrid
vic
rat
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Prototype of Chairperson and Layout Manager

• Algorithm of Chairperson
• Has one conversation group
• Removes a node which continues audio traffic to
  Speaker Group
• Uses AccessGrid window information (MAIN,
  AUDIENCE)

• Algorithm of Layout Manager
• Has three window sizes (large, middle, small)
• Displays all windows at speaker group
• Avoids overlapping each windows at speaker group
• Display high priority windows at environment group

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Demo Video
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Summary

• Acquisition of Network Scalability
• Dynamic multicast connection tool Dmconnect
• Acquisition of User-interface
• Vansyn to provide window layout functions for
  grasp the context from too many windows
• AccessGrid with Vansyn
• Test at our Lab.

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Feature Work

• Dmconnect (Network Scalability)
• Private address space
• Authentication
• Connection on demand
• Comparison between GRE tunneling and native
  multicast

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Feature Work

• Vansyn(User-interface Scalability)
• Extension of dialog model by system developer
• Progress of default Chairperson and Layout
  Manager
• Extension of AG-Vansyn
• Practical tests