What is Video Conferencing?

[Saku]

Videoconferencing uses telecommunications of audio and video to bring people at different sites together for a meeting. This can be as simple as a conversation between two people in private offices (point-to-point) or involve several sites (multi-point) with more than one person in large rooms at different sites. Besides the audio and visual transmission of meeting activities, videoconferencing can be used to share documents, computer-displayed information, and whiteboards.

Simple analog videoconferences could be established as early as the invention of the television. Such videoconferencing systems consisted of two closed-circuit television systems connected via cable. Examples are the German network set up between 1938 and 1940, and the British GPO lines at the same period.

Video conferencing is a live, interactive, full-motion, audio-visual communication between distant parties connected to each other by a communication network equipped with video endpoints. Generally, Video Conferences are set up in two different modes:
Point-to-point Video Conference: A Video Conference between two video sites.

Multiparty Video Conference : A Video Conference between three or more video sites. A video bridge is required to connect more than two video sites in a single conference.

Standards

• ITU H.320 is known as the standard for public switched telephone networks (PSTN) or VTC over integrated services digital networks (ISDN) basic rate interface (BRI) or primary rate interface (PRI). H.320 is also used on dedicated networks such as T1 and satellite-based networks;
  
• ITU H.323 is known as a standard for transporting multimedia applications over LANs. This same standard also applies to older implementations of voice over IP VoIP. In recent years, the IETF's Session Initiation Protocol (SIP) has gained considerable momentum in practice for these two services.
  
• ITU H.324 is the standard for transmission over POTS, or audio telephony networks. 3G-324M is a 3GPP implementation for video call on 3G mobile phones.

[sagi]

Multipoint videoconferencing allows three or more participants to sit in a virtual conference room and communicate as if they were sitting right next to each other. Until the mid 90s, the hardware costs made videoconferencing prohibitively expensive for most organizations, but that situation is changing rapidly. Many analysts believe that videoconferencing will be one of the fastest-growing segments of the computer industry in the latter half of the decade.