Videoconferencing

Videoconferencing can enable individuals and groups in various offices to have meetings on short notice. Time and money that used to be spent in traveling can be used to have both short and long meetings.

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 (point-to-point) or include several sites (multi-point) with many participants in large conference rooms at various locations. Besides the audio and visual transmission of meeting activities, videoconferencing can be used to share documents, computer-displayed information, and whiteboards. The most recent and exciting developments in videoconferencing includes incorporating high definition technology (HD) increasing the quality and realism of the visual and audio experience.

The core technology used in a video teleconference (VTC) system is digital compression of audio and video streams in real time. The hardware or software that performs compression is called a codec (coder/decoder). Compression rates of up to 1:500 can be achieved. The resulting digital stream of 1s and 0s is subdivided into labelled packets, which are then transmitted through a digital network of some kind (usually ISDN or IP).

The other components required for a VTC system include:

• Video input: video camera
• Video output: LCD, plasma, or projector
• Audio input: microphones
• Audio output: speakers associated with the display device or stand alone speakers
• Data transfer: digital data network: LAN, Internet, ISDN, PRI

There are basically two kinds of VTC systems:

1. Dedicated systems (manufactured by companies such as Polycom, Sony, and Tandberg) have all required components packaged into a single piece of equipment, usually a console with a high quality remote controlled video camera. These cameras can be controlled at a distance to pan left and right, tilt up and down, and zoom. They became known as PTZ cameras. The console contains all electrical interfaces, the control computer, and the software or hardware-based codec. Omni-directional microphones are connected to the console, as well as a monitor with speakers and/or a video projector. There are several types of dedicated VTC devices:
   • Large group VTC are non-portable, large, more expensive devices used for large rooms and auditoriums.
   • Small group VTC are non-portable or portable, smaller, less expensive devices used for small meeting rooms.
   • Individual VTC are usually portable devices, meant for single users, have fixed cameras, microphones and speakers integrated into the console.
2. Desktop systems are add-ons (hardware boards, usually) to normal PCs, transforming them into VTC devices. A range of different cameras and microphones can be used with the board, which contains the necessary codec and transmission interfaces. Most of the desktops systems work with the H.323 standard. Videoconferences carried out via dispersed PCs are also known as e-meetings.

Multipoint videoconferencing

Simultaneous videoconferencing among three or more remote points is possible by means of a Multipoint Control Unit (MCU). This is a bridge that interconnects calls from several sources (in a similar way to the audio conference call). All parties call the MCU unit, or the MCU unit can also call the parties which are going to participate, in sequence. There are MCU bridges for IP and ISDN-based videoconferencing. There are MCUs which are pure software, and others which are a combination of hardware and software. An MCU is characterized according to the number of simultaneous calls it can handle, its ability to conduct transposing of data rates and protocols, and features such as Continuous Presence, in which multiple parties can be seen onscreen at once.

MCUs can be stand-alone hardware devices, or they can be embedded into dedicated VTC units.

Some systems are capable of multipoint conferencing with no MCU, stand-alone, embedded or otherwise. These use a standards-based H.323 technique known as "decentralized multipoint", where each station in a multipoint call exchanges video and audio directly with the other stations with no central "manager" or other bottleneck. Users can make ad-hoc multipoint calls without any concern for the availability or control of an MCU. This added convenience and quality comes at the expense of some increased network bandwidth, because every station must transmit to every other station directly.

In-House Communication is your one-stop shop for all your videoconferencing needs. If you are a novice, or have many years of video experience, IHC will work with you to find the best solution. IHC provides a variety of the needed hardware, custom room integration services, installation and maintenance, internal bridge management, public rooms, and bridging service. Let IHC know how we can help you get started with video or maximize your existing video strategy.