Videoconferencing System
The Cong Giang EAP IT Manager
Participants – What do you know
about Videoconferencing?
• What is Videoconferencing? • What are basic equipments?
• Frame rate (VC, TV broadcast and Film)? • GDLN frame rate?
What is Videoconferencing?
• A technology that allows
– Two or more people at different locations to see and hear each other at the same time
– Also to share computer applications such as Internet pages, library catalogs, documents, or software
• Normal videoconference frame rate varies from 5-30/sec while regular TV broadcast is about 30
Types of VC
Since 1995 VC has started taking off. Initially
– Two basic units: TV and BOX+camera – Difficult to operate and connect.
– High cost of ISDN
VC Capabilities
A complete VC System provides two-way (send and receive) communications using the following media:
– Video:
• inputs from: TV camera, document camera, Cable TV, VCR, Streaming Video;
• outputs to: TV monitor, color projector, PC monitor)
– Voice
• inputs from: microphone, VCR;
• outputs to: speakers, headphone and interpretation
– Data:
• inputs from: keyboard, PC hard drives, network;
• outputs to: PC monitor, printer, local/network hard drives
– Telematics
• inputs from: keyboard commands; • outputs to: remote camera control, etc.
VC - Interconnection
The Videoconferencing Systems can interconnect with each other in a number of modes such as:
– Point-to-point – Multipoint
Distance Learning Requirements
To fully satisfy all the Distance Learning requirements, the following components should be added to sites with the Videoconferencing Systems:
– Additional system for on-line data interactions (between the teacher and students)
– Facsimile
– Overlay Teleconferencing System (based on the multipoint telephone sessions)
– Networked computer classroom. – Interpretation System
Basic Videoconferencing Technology
• audio-visual equipment (monitor, camera, microphone, and speaker)
• a means of transmitting information between sites • Cost of these two methods of transmissions:
– a broadband satellite connection with studio-quality equipment produces an excellent full-motion video connection and
– Advances in ICT have sparked an interest in
compressed video systems which transmit information via the Internet using Internet Protocols (IP) and digital telephone networks such as ISDN.
The Distance Learning Requirements
The technology support must provide the concurrent interactions such as:
– Voice interactions (student or teacher originated, with the Help Desk, with the Technical Support)
– Data interactions (on-line: questions and answers, polling, test, print file, fax; off-line: E-mail, database search)
– Video interactions (two-way live video, two-way still (document) images, two-way PC graphics, one-way streaming video).
VC - Three Types
• Portable Units • Desktop
Portable Units
• All of the equipment is loaded onto a rolling cart and moved to whichever location needs it.
Convenient. (WB COs)
• To add more equipment becomes problematic • Require more setups and testing
Desktop VC
• Because of advances in technology, fast ethernet as a cheap delivery media
• IP-based desktop systems: a PC, an inexpensive
camera, a microphone, a speaker, software • Sharing: See and edit file on the screen
• Low cost and suitable for informal communications
Intergrated System
• Classroom style: equipment are integrated and physically fixed into the classroom design.
• Multiple monitors/large screens • Multiple microphones
• Lecturer presents to participants (attending both locally and remotely)
• Interpretation equipment
Connections
• Significant distinction among VCs: How data is transmitted
• Before: Systems were proprietary – each has its own standard
• Now: Most systems are standards-based: They can connect with any equipment using the same standard
Three Standards
• H.320 (ISDN): The ITU-T standard for integrating
voice, digitized video, data and control messages in the same session established through the
Public ISDN and/or set of dedicated links in any Private Network.
Three Standards (cont.)
• H.323 (IP): Similar to H.320 but intended for
connections based on the Internet Protocol (IP). • A new standard, H.350: A relatively new video
compression standard developed by the Internet2 Middleware Initiative Video Working Group
Additional connection considerations
• Gateways allow different conferencing protocols to
connect to each other by receiving and translating data • A gatekeeper is special sofware that runs on a computer
or dedicated server and manages the activities of multiple conferences.
• An MCU (multipoint control unit) enables multiple sites to participate in a videoconference
MCU
To interconnect three or more systems while
using such a mixture of media, we need a special computerized device called the Multipoint
Questions
• Q1: Types of VC systems EAP GLDN • Q2: Types of VC systems in WB COs
• Q3: Connection standards in EAP GDLN
– Co-Located – Stand-alone
