Glossary of terms

Glossary of terms.

Bandwidth – Capacity of a network or network segment to receive and transmit video, audio, and data.

CIF – (Common Intermediate Format) An intermediate video format with a resolution of 352×288 pixels. Compare to "QCIF" (quarter CIF) at 176×144 pixels.

Codec – A device for encoding an incoming analog signal into a digital signal for transmission to another codec. In videoconferencing, a codec typically codes and decodes video and audio and is an essential component of a video endpoint.

Conference Bridge, or MCU – Hardware and software device on a videoconferencing network that allows multiple video endpoints to participate in a multipoint conference. Typically deployed in environments requiring conference management, scheduling, and scale.

Continuous Presence – State within a multipoint conference in which all parties remain continuously visible or "present." Compare to "Voice Activated Switching."

Content – Any data such as presentations, spreadsheets, schematics, etc. that can be displayed and presented to far side endpoints, or received and view on the near side.

Desktop Video Client – A software application used to communicate over video with telepresence and video conference systems. One example is the Polycom CMA Desktop, which enables a person on a PC to communicate clearly and with great clarity to other video clients such as desktops, conference rooms, and Immersive Telepresence suites.

Encryption – Alteration of transmitting information to protect it from unauthorized tapping.

Far End / Far Side – The remote party or parties connected to a call. Contrast to "Near End / Near Side."

Frames Per Second (fps) – Frequency with which video frames appear. Broadcast quality video generally consists of 30 frames per second. Full motion videoconferencing typically offers video in the range of 10 to 15 frames per second. At very low bandwidths, such as 56 or 112 Kbps, the frame rate may be lower.

Firewall – A network node set up as a boundary to prevent traffic from one segment to cross over into another.

Gateway – An entity that provides real-time, two-way communication between dissimilar (H.323 and H.320) video endpoints operating across dissimilar networks by reformatting data and protocols.

H.323 – The umbrella for a set of standards defining real time multimedia communications for packet based networks otherwise known as IP telephony. H.323 is comprised of the following standards: H.225, H.245, G.711, G.722, G.723.1, G.728, G.729.

High Definition (HD) – Refers to a video system of higher resolution than standard-definition (SD) video, most commonly at display resolutions of 1280×720 (720p) or 1920×1080 (1080i or 1080p).

High Resolution -Refers to video systems with display resolutions approximating 704×480 (480p) (16:9 aspect ratio) or 704×480 (4:3 aspect ratio).

Internal Multipoint -Capability within a video or telepresence endpoint to bridge multiple parties in a single simultaneous video conference.

Interoperability – The ability to communicate between different codecs.

Jitter – The variation in packet delay as packets cross the network, characterized by stilted video motion quality.

Latency – Delay in the response of far end participants, often a result of network congestion and geographic distance.

Lost Packet Recovery – Unique to video endpoints and conference platforms from Polycom, a technology sustaining video and audio interaction quality across "dirty" or irregularly performing networks.

Management – The ability to view, control, provision, update, and allocate resources and rights to video and telepresence endpoints and conference bridges within a video ecosystem. Characterized by a centralized application, management also commonly provides gatekeeper functions, conference scheduling activities, integration with existing IT directory structures, and alarm notifications.

MCU – See "Conference Bridge"

Multipoint Conference – Communication between more than two sites. Multipoint conferences may be established internally within a video endpoint, or through an external dedicated device such as a Conference Bridge.

Near End / Near Side – The local side with a videoconference.

Presence Awareness – From a user interface, the ability to graphically discern the state of a (video) endpoint and/or user. Common states include "Available", "Unavailable", "In a meeting", and "Do Not Disturb."

QCIF (Quarter Common Intermediate Format) – A video resolution one quarter the size of CIF. Typically used in very low bandwidth videoconferences. Compare to CIF.

Resolution – A measure of sharpness or clarity on a display.

Telepresence – A technology that enables highly life-like, face-to-face interactions to occur between individuals and groups over distance. Characterized by high definition video, audio, and content. Subcategories Include "Immersive", "Room", and "Personal".

Video endpoint – A video conferencing system such as a camera and codec, or in the case of immersive telepresence suite, an entire room composed multiple cameras and codecs that provide a unified life-like experience.

Voice Activated Switching – A mode in a multipoint videoconference that switches the window view to the participant site currently speaking. Compare to "Continuous Presence."

Video conferencing is being deployed more widely and has incorporated the use of computers as well as traditional set top systems. To find out more about video conferencing or any of the items listed on this page contact cs@videoconferencinglondon.co.uk or visit our main web site www.videoconferencinglondon.co.uk

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