Past, Present and Future of Videoconferencing at the University of Ghent

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Past, Present and Future of Videoconferencingat
the University of Ghent

• Geert De Soete and Michel Raes
• Academic Computing Center, University of Ghent,
  Belgium

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Overview

• Centrally provided videoconferencing facilities
  at Ghent University
• The Multimedia Room
• Technology
• Costs
• Types
• Quality
• Outlook

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Centrally provided videoconference facilities

• The Multimedia room
• History
• 1995 Decision to build
• October 1996 First course
• ...
• 1999-2000 4 or 5 videoconferences per week
• Concept
• Examples of usage

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Examples of usage

• Local lecture with remote audience

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Examples of usage

• Remote lecture with local audience

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Examples of usage

• Group discussion for project management

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Examples of usage

• PhD defense presentation from a remote site

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Examples of usage

• PhD defense with local and remote jury members

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Technology currently adopted

• Modular setup with heterogeneous equipment
• more flexibility
• higher integration efforts
• H.320 compatible Codec using ISDN
• flexible call set-up
• acceptable price-to-quality ratio

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Technology currently adopted

• The ITU H.320 standard
• Compatibility interoperability
• Problems in the past now resolved
• small differences in implementation
• pre-standard implementations
• proprietary and non-standard protocols

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Technology currently adopted

• ISDN Digital, circuit switched, connection
  oriented, constant bitrate technology
• Widely available in developed countries
• But different implementations eg. Euro-ISDN
• International connectivity was a problem
• Now interconnection is seamless and reliable
• Not available to some partners Russia, Vietnam
• Some possiblities with partners in China, Ecuador

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Some notes on costs

• Different bandwidths possible
• Basic quality 128 kbps ( 2B )
• Medium quality 256 kbps ( 4B )
• High quality 384 kbps ( 6B )
• Proportional price-to-quality
• The party initiating the call has to pay
• Differences between countries and operators !

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Some notes on costs

• Cost overview
• 256 kbps is a good price-to-quality compromise

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Types of videoconferences

• Point-to-point videoconferences
• Simply connect two sites to each other
• Multipoint videoconferences
• Connect three or more sites

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Point-to-point videoconferences

• Require little preparation
• exchange of essential information
• short test connection
• Easy technical set-up
• By dialling the correct number
• Easy organisation like a normal meeting

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Point-to-point videoconferences

• Examples
• Cryptography course with KUL
• Computer graphics course with Xerox
• Ghent University PhD defense with the candidate
  in the USA
• Ghent University PhD defense with a jury member
  in Australia
• ...

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Multipoint videoconferences

• Connect three or more sites to each other
• Technically complex
• Star topology with an MCU in the center
• MCU image selection, audio multiplexing
• Complex to organize
• Practical arrangements
• Extensive testing

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Multipoint videoconferences

• Examples
• Aquarius project management meetings with Ghent,
  Wageningen (NL) , Trondheim and Bergen (N)
• PhD defense in Ghent with jury members in
  Stirling (UK) and in Bordeaux (F)
• Continuing education courses on Information
  Technology with 12 participating sites
• ...

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Quality

• Overall perceived quality is determined by
  technology related factors
• Audio quality
• Video quality
• Eliminating distance

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Audio quality

• Audio quality is a critical factor for room
  videoconferencing
• H.320 audio quality is in principle good
• Telephone grade quality for low bandwidth
• Short delay, echo cancellation, voice-to-image
  synchronization
• No risk for audio drop-outs

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Audio quality

• Overall audio quality also depends on
• room acoustics
• amplifying circuitry
• type of microphones
• the way the person talking uses the microphone
• Precise tuning by the operator is a necessity

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Video quality

• H.320 video quality is rather poor
• at least compared to broadcast TV quality
• CIF resolution 352 x 288 pixels
• Changing or moving images need time to stabilize
• More bandwidth only gives faster response in
  moving images, but no better resolution !

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Video quality

• Is no problem for viewing a person talking
• Is a problem for visual materials
• transparencies or printouts (via document camera)
• computer presentations (via scan converter)
• Solution adapt to the restrictions
• prepare visual materials according to specific
  guidelines for videoconference lecturing
• have a test session to show how the materials
  will be percieved on a remote site

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Quality Eliminating distance

• The goal virtually eliminate physical distance
  between remote sites
• solving mobility problems
• reducing transport costs
• Limitations
• the technological environment
• practical factors like time difference in
  interconentinental connections
• difficulty to maintain good interactivity for
  teaching

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Outlook to future trends

• T.120 data sharing
• ATM-based videoconferencing
• IP-based videoconferencing
• Gateways

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Outlook T.120 data sharing

• T.120 transmitting visual materials as data
• resolution 800 x 600 ( instead of CIF ! )
• application sharing, whiteboard
• Most systems rely on Microsoft NetMeeting
• System integration ?
• 2 viewing circuits are necessary in a room setup

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Outlook ATM-based VC

• ATM-based VC in the past
• High cost
• Poor interoperability
• ATM-based VC in the future
• more products for H.310 (native ATM)and H.321
  (IP over ATM)
• But ATM deployment remains uncertain...

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Outlook IP-based VC

• IP-based VC in the past
• Unpredictable performance over WAN
• Low quality eg. audio drop-outs by packet loss
• No industry standard for interoperability
• Mbone tools for specialized academic users
• IP-based VC now
• ITU H.323 standard
• good performance over high speed LANs

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Outlook IP-based VC

• IP-based VC in the future
• Increase in bandwidth in IP networksGigabit /
  Terabit IP backbones using fiber optic
• Implementation of QoS mechanisms in IP
  networksRSVP, DiffServ
• more H.323 compatible products

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Outlook Gateways

• Connecting heterogeneous technologies for
  videoconferencing in a transparant way
• H.320 ( ISDN )
• H.321 ( ATM )
• H.323 ( IP )

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Outlook Multimedia Room

• Extension plans for the videoconference room of
  Ghent University
• H.323 codec for IP videoconferencing
• H.320 - H.323 gateway

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Past, Present and Future of Videoconferencingat
the University of Ghent

• Geert De Soete and Michel Raes
• Academic Computing Center, University of Ghent,
  Belgium