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What is video conferencing and how does it work?

At the simplest level, a video conference is an online meeting (or a meeting over distance) that takes place between two parties, where each participant can see an image of the other, and where both parties are able to speak and listen to the other participants in real time.


The components to make this happen include:

• A microphone, webcam and speakers

• A display

• A software program that captures the voice stream from the microphone, encodes it, transmits to the other participant, and simultaneously decodes the digital voice stream being received from the remote participant in the video conference (most commonly referred to as a “Codec”).

• A software program that bridges both parties together across a digital connection, managing the exchange of voice and video between participants. At either end of the connection, the video and voice traffic is combined and delivered to each participant in the form of a real-time video image and audio stream.

Terminology used by video conferencing users to describe the process of dialing into and participating in a virtual meeting is known as “joining a bridge.” Different virtual meeting rooms are assigned unique “bridge numbers,” and users join a video call by “dialing a bridge number.”

Video-enabled meetings happen in two distinct ways: either point-to-point or with multi-point. In point-to-point, the simplest scenario is where one person or group is connected to another. The physical components (i.e. microphone and camera) that enable the meeting to take place are often integrated in to desktop computing solutions like a laptop or tablet, or can be combined into dedicated, room-based hardware solutions. Where desktop solutions tend to be used by individuals, room-based solutions utilize dedicated video conferencing technology where groups of people can be seen, heard and can naturally participate in the meeting.

In multi-point video calls, three or more locations are connected together, where all participants can see and hear each other, as well as see any content being shared during the meeting. In this scenario, digital information streams of voice, video and content are processed by a central, independent software program. Combining the individual participant’s video and voice traffic, the program re-sends a collective data stream back to meeting participants in the form of real-time audio and video imagery. Individuals can participate in a meeting in an “audio only” mode, or combine audio with video images of the meeting on screen allowing meeting participants to view and interact in a ‘virtual meeting room.’ The software program which creates the “virtual meeting room” and the digital processing hardware on which it resides, is often called a video bridge, or “bridge”, for short. Another term for a bridge which is often used is a video conferencing “multipoint control unit” or “MCU.”