Kretov Nikolai Nikolaevich: Video conferencing systems

Videoconferencing is the ability to exchange sound, video and information between several points equipped with special hardware and software equipment. Participants in a video conference have the ability to hear and see each other at the current time, as well as to process the data exchanged together.

Many consider owning video conferencing systems to be fun. And such a system can greatly increase the productivity of the people who use it, who have the need to communicate without moving and the associated costs, exchange of information at the right time, common work on a joint project in the case when its participants are remote from each other at any distance within the globe .

The earliest appeared in the 80s. videoconferencing systems were very expensive due to the need for high-speed communication lines, special rooms and operators.

Today, working with video conferencing facilities is simple and financially acceptable for large companies due to the emergence of codecs, high-speed data transfer (for example, ISDN), and the introduction of standard software.

The current videoconferencing system is based on the use of a means of encoding or decoding signals - a codec. He appeared in 1981. These devices (programs) that perform compression-decompression of signals: video or audio, make it possible to transmit them over communication channels that have a low speed. Thanks to codecs, video communications are carried out over standard networks.

Along with the promotion of codecs, various network technologies were developed and implemented, the cost of their use was reduced. As Integrated Services Digital Networks (ISDN) became widespread around the world, video conferencing systems became more popular. As a result of combining six basic ISDN channels, giving a bandwidth of 384 kbps, it becomes possible to transmit high-speed frames (30 frames per second) in video images, which gives high-quality playback on a computer display.

Video conferencing systems are divided into three groups:

• Videoconferencing for classrooms or studio - usually unite one speaker with a large group of people, are systems of the highest quality.
• group videoconferencing - for simultaneous communication between participating groups.
• Personal video conferencing - for simultaneous communication of two people.