Desktop Videoconferencing

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Desktop Videoconferencing

• by
• Gerald Knezek
• Rhonda Christensen

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Terminology

• Teleconferencing
• audio
• combined audio/video
• videoconferencing implies audio
  also (continued)
  

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• (continued)
• Desktop Videoconferencing
• One form of Teleconferencing
• Phone-line based
• Lumaphone (black white, 350)
• Sony, ATT (color, 1K)
  (continued)

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• (continued)
• Internet based
• Audio system (Internet Phone, Mave, 0-100)
• Video/keyboard typing system (Original CU SeeMe,
  free)
• Combined Audio-Video (Commercial Systems, lt150)

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Videoconferencing Distinctions

• Frame Refresh Rate
• gt 24 frames per second required to perceive full
  motion
• full motion (TV) systems provide 30 FPS
• partial motion systems provide about 15 FPS
• (continued)

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• (continued)
• internet based systems provide 5-15 FPS (CU
  SeeMe)
• Slow-Scan TV provides 1 frame every 4 seconds
• Cost
• Higher fidelity requires more bandwidth
• Color costs more
• Usually trade off audio for video quality

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IP Addresses

• Unique Identifier (like phone number)
• 129.120.20.91 for Mac Quadra in 322G
• 129.120.20.127 for Mac Mac IIsi in 322
• (continued)

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• (continued)
• 129.120.20.2 for CECS Reflector
• alias pizza.cecs.unt.edu
• Similar addresses exist for hundreds of public
  reflectors

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Internet Conferencing Tools

• CU SeeMe (v.68k0.80b2)
• videoconferencing from Internet (T-1, SLIP, PPP)
• point to point vs. reflector
• max 2 participants with former
• uninvited participants with latter
• (continued)

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• (continued)
• Maven/Internet Phone (v.2.0a37)
• audioconferencing
• takes priority over video
• Special considerations
• gt8 Mb RAM (w/system 7.5) to run both
• Audio input for AV machines
• Camera technology

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Reflector Site vs. Point-to-Point

• Reflector Sites
• Public
• Usually allow max. of 8
• (continu
  ed)

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• (continued)
• Point-to-Point
• Private
• Allows max of 2 for CU SeeMe (Mac)
• Allows max of 8 with Maven
• Private Reflectors
• restricted access through code
• combines privacy and multiple access rights

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• The End