Jargon Buster

  • Active matrix

    A controller which allows the brightness and colour of every pixel on an image to be adjusted.
  • Aliasing

    Otherwise known as ‘twittering’, this is a problem associated with interlaced video sources and affects the sharp lines and edges during camera movement, causing objects to shimmer.
  • ALIS

    Standing for Alternate Lighting of Surfaces is a method of achieving high definition and high brightness.
  • Ambient light

    Any other lighting present in a room apart from the light emitted by a projector.
  • Analogue

    Analogue signals are the traditional format in which audio and video are transmitted. Nowadays digital signals are more popular as they tend to give a better quality.
  • ANSI

    American National Standards Institute.
  • ANSI lumens

    The degree of lamp brightness, measured in candela.
  • Aperture

    The hole behind a lens through which light is allowed to pass.
  • ASF

    Advanced Systems Format is a file format which enables digital media data to be streamed over a network. Active Streaming Format is the standard file format of WindowsMediaTM Technologies files.
  • Aspect ratio

    An aspect ratio is a figure that represents the width-to-height ratio of an image. The easiest way to explain aspect ratios is to use an example. Take the aspect ratio 4:3. The first number, 4, signifies the width of the image while the second number, 3, indicates the height in any given unit of measure.
  • Attenuation

    The loss of signal in a transmission system.
  • Audio in and out

    Connections for external amplifiers and speakers to allow sound output.
  • Auto balance

    Automatic correction of errors in colour balance in black and white areas of an image.
  • AVI

    Audio Video Interleave is a digital file format which develops and stores sound and video.
  • Bandwidth

    The amount of information that can be transmitted over a network connection, digital connections measure bandwidths in bits per second, Kilobits (Kbps), Megabits (Mbps) and Gigabits (Gbps).
  • Bit

    Short for ‘binary digit’, a bit is a measure of bandwidth.
  • Bit rate

    The number of bits transferred, typically expressed in bits per second, i.e. a file compressed to 28.8Kbps contains 28.8 kilobits of data for each second.
  • Bitmap

    A picture contained on a web page in various formats, including JPG, GIF and TIF.
  • BNC Connector

    A Bayonet Neill Concellman is a connector often used on high end video equipment.

    The Basic Rate Interface converts normal telephone wires into three signalling channels carrying voice and data. They are commonly used in high quality ISDN video conferencing systems.
  • Buffer

    An area of computer memory reserved for holding and compiling sufficient data to begin streaming.
  • Built-in loop through

    A built-in loop through within a projector enables an additional screen or projector to be connected and display the same signal.
  • Chroma

    The chroma, or chrominance, is the characteristics of a picture’s colour saturation and its hue.
  • Codec

    An encoder or decoder is the device through which outgoing video and audio signals are coded and the incoming signals decoded in preparation for playback.
  • Colour depth

    The number of colours that can be displayed by a device i.e. 16-bit colour, 32-bit colour, etc.
  • Colour temperature

    The amount of ‘whiteness’ in a light source, measured in Kelvins.
  • Combing

    Combing affects vertical lines during camera movement producing a shimmering effect on interlaced video sources.
  • Composite video

    This is one of the most common AV connections and is the picture signal combined with synchronisation and colour information.
  • Compression

    Compressed data uses less bandwidth, saving computer memory space and enabling faster transmission. In display equipment, compression is used to convert resolutions, such as from XGA to SVGA, resulting in a clearer, sharper picture.
  • Configuration

    The technical specifications of a computer, typically including processor speed, memory, video card type etc.
  • Continuous presence

    A split-screen function that allows multiple views to be displayed simultaneously on the same screen.
  • Contrast ratio

    The ratio of darkness to brightness of a scene. A contrast ratio of 400:1 relates to the lumen output of a projected white image being 400 times larger than the projected black image.
  • Convergence

    The three primary colours (red, green and blue) are used to produce all colours. All three are converged to produce ‘white’.
  • CRT

    Cathode Ray Tube.
  • D-ILA

    Direct Image Light Amplification is a technology patented by Hughes-JVC designed to improve the light output and contrast ratio of LCD screens.
  • Data

    Information that can be found in various forms, including text, numbers, sounds and pictures that can be processed by a computer.
  • Data compression

    Through data compression, unnecessary information can be removed from a data file to save space.
  • DCDi

    Directional Correlation Deinterlacing is a technology which can eliminate jagged edges from moving video.
  • Decoding

    Compressed audio and video content can be decoded to a specified digital format, for example MPEG.
  • Desktop video conferencing

    Personal video conferencing run on a smaller scale on a desktop model, suitable for individual use or within small workgroups.
  • Dichroic

    A mirror or lens that reflects /refracts wavelengths of light and separates the white light source into red, green, and blue light.
  • Digital Keystone Adjustment

    This adjusts and corrects the keystone on a projected image, i.e. to produce a perfect, square-shaped image.
  • Digital media

    Images, sound, text and videos in a digital format that can be downloaded or streamed across the internet and networks.
  • Digital signal

    Digital signals can be transmitted faster than analogue signals and represent a more accurate transmission of computer information.
  • Digital zoom

    This function enables the zooming in and out of images quickly without losing picture quality.
  • Distribution amplifier

    This allows a source signal to be amplified and distributed through multiple outputs over long distances.
  • DLP

    Digital Light Processing is a recent development by Texas Instruments which uses mirrors to display an image. DLP is superior to LCD and is used in most low to mid- range projectors.
  • DNS

    Domain Name System refers to the name resolution system that allows users to locate computers on a Unix network or the Internet (TCP/IP network) by domain name. The DNS server maintains a database of domain names and their IP addresses.
  • Download

    The transfer of files to a computer and the method of installation of software from a website.
  • DPI

    Dots per Inch refers to the number of pixels in a single inch line.
  • DRM

    Digital Rights Management is the technology which maintains the protection of digital content through encryption.
  • DSP

    Digital Signal Processing refers to manipulating analog information, such as sound or photographs that has been converted into a digital form.
  • DVD

    Digital Video Disc is the latest format for optical storage media with several times the capacity of Compact Discs (CD).
  • DVI

    Digital Visual Interface represents the interface between projectors and computers through a digital connection, resulting in a clearer image than that produced through an analogue connection.
  • Echo cancellation

    The built-in process which removes any acoustic echo in a video conferencing environment.
  • Eco-Mode Technology

    A money-saving, highly efficient feature that doubles lamp life and produces a quieter operation.
  • Encoding

    The conversion of audio and/or video content to a specified digital format, including MPEG, by an encoder.
  • F-stops

    The aperture of a lens.

    The formats for communicating between video conferencing systems.
  • Firewall

    Hardware and/or software which prevents unauthorised access to private networks.
  • Flash

    Graphics software that relies on less bandwidth than traditional video.
  • Focal length

    This is the distance from the surface of a lens to its focal point.
  • Focus

    A projector’s focus defines minimum and maximum projection distances. Most projectors have both auto and manual focus functionality.
  • Format

    The different ways that information is stored on a program or device, i.e. VHS, DVD, PDF and MPEG.
  • Frame

    The series of images that produce video and the frame rate is the number of video frames displayed per second.
  • FTP

    File Transfer Protocol is an internet protocol which enables users to transfer files over a network.
  • Full duplex

    A common feature of video conferencing, this two-way audio is simultaneously sent and received without interference or ‘clipping’.
  • Full motion video

    Real time video which is equivalent to broadcast television quality with a frame rate of 30 fps.
  • Gateway

    A network point that acts as an entrance to another network and a router or computer that converts protocols between different types of applications or networks.
  • Ghosting

    A trail left by a moving object on a slow LCD panel.
  • GIF

    Graphics Interchange Format is a graphics format where images are made up of pixels and can be downloaded quickly.
  • Graphics

    Anything that appears on a web page that is not text.
  • Halogen

    A light source used in projectors.
  • HDCD

    High Definition Compatible Digital is a patented encoding/decoding process which improves the quality of digital audio recording and playback.
  • HDMI

    High-Definition Multimedia Interface is the new standard for video interfacing with a bandwidth of up to 5Gbs. It can easily support all current HDTV standards and is backwards compatible with DVI.
  • Horizontal/vertical lens shift

    The feature of a projector which facilitates precise image positioning for fast installation and usage.
  • Host

    The computer which provides documents to users and functions as the beginning and end points for transfer of data.
  • HTML

    Hypertext Markup Language is the standardised language of the web and is embedded in all web documents.
  • HTTP

    Hypertext Transfer Protocol is the internet protocol used to deliver information over the web.
  • Hue

    A single colour disregarding brightness or luminance.
  • Intensity Shading

    Audio – Reducing the output of the lower section of an array.
  • Interface

    The connection between different elements of a system. In software an interface refers to the software a computer runs to enable the user to interact with it.
  • Interlaced video

    The integrated image that the eye sees when the image from video’s two fields are delivered to a video device such as a television.
  • Internet Protocol (IP)

    These protocols are used to communicate across interconnected networks and are often used for common applications such as e-mail, terminal emulation and file transfer.
  • Intranet

    An internal computer communications network.
  • ISDN

    Integrated Services Digital Network is the recommendation published by CCITT for private or public digital telephone networks. In ISDN transmission, binary data passes over the same digital network that carries common telephone transmissions.
  • Java

    A network-oriented programming language designed for writing programs to be downloaded through the internet.
  • JavaScript

    The programming language created that helps make web pages more interactive.
  • Jitter

    Jitter is the distortion caused by signal variation in analogue communication lines and can cause data loss.
  • JPEG or JPG

    Joint Photographic Experts Group is a compression technique for still images that reduces them to a small percentage of their original file size.
  • Key frame

    A video frame that contains all the data required to produce an image without any reference to the previous frames.
  • Keystoning

    The angle created when an image is projected can slightly distort the shape of the image. Keystoning is a projector feature that corrects the shape by creating a uniform image, top to bottom.
  • Keyword

    A word or phrase typed into a browser to start an online search.
  • LAN

    Most Local Area Networks are confined to one or more buildings and are used to connect workstations, printers and other similar devices. LANs provide access to data and device anywhere on the LAN which can be shared by other users.
  • Latency

    The delay that occurs during the time that a device processes and delivers data.
  • LCD

    Liquid Crystal Displays. LCD technology uses three glass panels which sandwich crystals and separate the colour spectrum into red, green and blue. When light is passed through the panels an image is created on the screen.
  • Lip sync error

    This occurs when picture and sounds are not synchronised in time when playing video.
  • Local playback

    A file that exists on the same computer device as opposed to one stored on an external source such as the internet.
  • Lossless compression

    The process of compressing data where information is arranged more concisely and restored to its original state upon decompression.
  • Lumen

    A lumen is a measurement of light. The higher the lumen count is the brighter the projection will be.
  • Luminance

    The colour intensity of an image.
  • M1 Connection

    A display interface system developed for digital displays that can carry DVI, VGA, USB and Firewire.
  • MAC address

    A Media Access Control address is a hard-coded interface identification used by layer 2 devices (switch or bridge) for proper forwarding of frames between computers on a network.
  • Maximum resolution

    This number has nothing to do with the products physical display . Instead it has to do with signal formats. Computer and video signals come in a wide variety of resolution formats. And every projector is programmed to recognize many of those different signals. Maximum resolution is the highest resolution signal that the projector has been programmed to process and display.
  • Memory

    The amount of data that a computer can store on a disk or chip.
  • Metadata

    More detailed information about data.
  • Metal Halide

    These are used in most projectors and give a brighter image and last longer than halogen.
  • MIB

    Management Information Database.
  • Microperforated screen

    A screen which can have a speaker mounted to the rear of it.
  • MLA

    Micro Lens Array increases the fill factor on LCD panels and reduces the visibility of the pixel grid to almost zero so that the rows and columns of pixels cannot be seen when viewing from a comfortable distance.
  • Mouse emulator

    The remote control on a projector usually features a mouse emulator. This means the user can move around during a presentation whilst retaining control of the computer source.
  • MP3

    MPEG Audio Layer-3 is the audio compression standard.
  • MPEG

    Moving Picture Experts Group is a type of audio or video file.
  • Multicast

    A method of delivering content via a single stream which is then transmitted from a media server to multiple clients who have no connection with the server.
  • Multichannel audio

    An audio reproduction system that processes various sound channels.
  • Multimedia

    A range of media, including graphics, animation, sound, video and text.
  • Multiplex

    In computing, this is where a signal is divided into several parts. In video conferencing, this is the combination of two or more signals from two or more channels into a single output. Those multiple channels must be multiplexed or de-multiplexed with a
  • Multipoint Control Unit (MCU)

    Also referred to as a bridge, this is a device that manages video conferences involving three or more participants.
  • Multipoint video conference

    A video conference involving more than two locations.
  • Native resolution

    Native resolution is the actual, true, physical resolution of the display device. We would recommend that you match the Native resolution to the primary output resolution of the intended source devices.
  • Network

    Two or more computers link together to form a network.
  • NTSC

    The National Television Standards Committee is the video transmission system used in the US, Canada and Japan.
  • On-demand

    Instant access to archived or stored content when required.
  • OSD

    The On Screen Display is the menu that enables the user to access and adjust a monitor’s settings, including brightness, image position and colour saturation.
  • Overlay

    This occurs when computers overlay text and graphics onto images.
  • Overscan

    Overscanning occurs where the area of a video picture falls outside the viewable area of the display device.
  • PAL

    Phase Alternating Line is the standard for scanning television signals and is used in the majority of European countries.
  • Participant map

    A visual map which shows where the participants of a video conference are sitting.
  • PDF

    Portable Document Format was developed by Adobe Systems to capture and deliver most document types without changing the format or recreating it within another application. Acrobat Reader is required to view a PDF document.
  • Phosphor

    An organic material that produces light when stimulated by the electron gun in the CRT.
  • Pincushion

    The curve seen in an otherwise straight line at the sides of some displays (particularly CRT).
  • PIP (Picture-in-Picture)

    The ability to project a secondary image (from another source such as a DVD, VCR or PC) within the main projection image.
  • Pixel

    A tiny dot which represents a single element of a display. The more pixels an image has, the more defined the image will appear to the viewer.
  • Pixel frequency

    The amount of pixels that can be displayed on a monitor per second e.g. 110MHz.
  • Pixelation

    If compression by DVD and digital channels is not performed correctly, the image looks rougher and coarser than it should, with a grainy effect over parts of the picture.
  • Plasma display

    A plasma display is a video display in which each pixel on the screen is illuminated by a tiny bit of charged gas. Plasma displays are thinner than cathode ray tube (CRT) displays and brighter than liquid crystal displays (LCD).
  • Platform

    Platform refers to both a computer operating system, i.e. Windows, Macintosh, Linux and to the actual computer hardware, i.e. Macintosh or PC.
  • Playlist

    A list of digital media content.
  • Plug-in

    Software that extends the capabilities on a computer, for example to watch movies or access animation.
  • Point-to-point video conference

    A video conference between two sites/locations.
  • Polysilicon

    A material used in the manufacturing of LCD displays which results in a superior contrast ratio and quicker response time than TFT LCD screens.
  • Portable device

    A mobile electronic device, such as a pocket PC, digital music player or Smartphone, which can exchange files or data with a computer or other device.
  • Portal

    A website that acts as a starting point to other areas of the web.
  • Preamplifier

    An electronic device that increases a signal’s output level to match the signal input level of another device.
  • Presentation mode

    Also referred to as broadcast or lecture mode, presentation mode enables a single location to be viewed and heard during a conference by all participants.
  • Progressive scan

    Progressive displays can show progressive scanned images as opposed to interlaced and have the ability to draw every line of the projected image resulting in a clearer and more defined image.
  • Protocol

    A set of procedures and formats that enables computers to exchange data.
  • Proxy server

    A server on a network between client software and another service that intercepts requests to the server, forwarding to other servers if necessary.
  • Rainbow effect

    On DLP projectors, the inability of the DLP colour wheels to refresh pixels fast enough results in colour separation on the edges of fast-moving objects and is known as the rainbow effect. Some viewers are more prone than others to seeing the rainbow effect.
  • RAM

    Random Access Memory is the computer hardware used for the short-term storage of data.
  • RCA

    A connector used commonly on audio visual equipment.
  • Real time

    The actual time that an event takes place.
  • Rear Screen Projection

    The projector is positioned within a large cabinet, supporting an opaque screen and projects its image onto the screen from behind. Most projectors have the ability to mirror the image they produce in order to work within a rear projection cabinet.
  • Recommended resolution

    The recommended resolution a monitor can run at.
  • Refresh rate

    The rate at which a CRT monitor redraws an image, for example, a refresh rate of 85Hz or higher is considered flicker-free.
  • Resolution

    The clarity or sharpness of a picture described in dots per inch (dpi).
  • Response time

    A term associated with LCD technology, this is the time an individual pixel takes to turn fully on then off. There is a rising (r) and falling (f) time which gives the overall figure.
  • RGB

    Red, green and blue are the colours that, when combined, comprise all the colours on a computer screen.
  • RMS watts

    The average maximum power output of an amplifier or the maximum average power of a speaker which is measured at 0.1% THD (Total Harmonic Distortion).
  • Room-based video conferencing

    Video conferencing that uses a large, sophisticated system as opposed to desktop video conferencing.
  • S-video

    Super video is the signal transmitted as two sub-signals requiring two wires ? luminance (Y) and colour (C) and can only represent standard definition interlaced video signals
  • Saturation

    The strength or purity of a colour present within a television image.
  • Scaler

    A device that deinterlaces an image, then scales it to the native resolution of the output device. It can significantly enhance picture quality, particularly on plasma screens and projectors.
  • Scan converter

    In a projector, this converts a digital signal from a computer to a video signal for broadcast on a video projector or TV monitor.
  • Screen gain

    The extent to which a projection screen can make an image appear brighter.
  • SDI

    Serial Digital Interface is the standard used in broadcast and high end video systems for transmitting digital component video over a coaxial cable.
  • SDP

    Session Description Protocol is the multicast configuration file for MPEG-4 audio, video and network settings.
  • Server

    A computer that provides a service to client software that runs on other computers.
  • Set-top box

    A cheaper unit that replaces a destination decoder and streams to a television set.
  • Short throw lens

    These lenses are designed to project a large image from a short distance and most projectors are equipped with them.
  • SHP

    Super High Pressure Lamps.
  • Sound card

    A circuit or expansion board that adds audio functionality to a computer.
  • SPL

    Sound Pressure Level is the measure of effective sound and is measure in decibels (dB).
  • sRGB

    Standardized Red, Green, Blue is the colour space defined by Microsoft and Hewlett-Packard to match colour between applications and hardware devices such as monitors, scanners, printers, and digital cameras.
  • Standard compression algorithm

    A convention for the compression of a video signal.
  • Streaming

    Live, real-time transfer of digital information, including all multimedia over networks and the internet on demand and in a continuous flow, i.e. it is played by client software as it is received. Streaming files match the encoded bit rate to.
  • Sub pixel

    A pixel is made up of three same-sized, red, green and blue cells which produce the colour emitted by a display.
  • Subnet mask

    This is used to group IP addresses together, commonly used by routers to define the group to which an IP address belongs in order to identify the correct interface from which it should forward the IP packet.
  • SVGA

    Super Video Graphics Array refers to a display resolution of 800 pixels horizontally by 600 pixels vertically. This is currently the lowest projector resolution on the market.
  • Synchronisation

    The process of maintaining digital media files on a portable device such as an MP3 player.
  • Synchronous

    When circuits operate at the same speed.
  • TCP

    Transmission Control Protocol is the protocol of TCP/IP which governs the break-up of data messages into packets to be sent through IP and the reassembly and verification of the complete messages from packets received by IP.
  • TCP/IP

    Transmission Control Protocol/Internet Protocol is the common name for the suite of protocols developed by the American Department of Defense in the 1970s to support the development of international inter-networks.
  • TFT

    Thin Film Transfer offers more efficient use of the light source that creates the image from LCD panels.
  • Three panel LCD

    Projectors using one panel for each primary colour offer enhanced colour reproduction and a richer image.
  • Throw distance

    It refers to the minimum and maximum distance within which the projector will focus. Special attention should be payed to this distance when you are installing a projection system.
  • Thumbnail

    This is a small version of a page or image that provides a simple method of browsing multiple images.
  • TIF

    Tagged Information File format is a graphic file format for still images or bitmaps in web pages.
  • UHE

    Ultra High Efficiency is the term typically used with metal halide lamps.
  • Upload

    The opposite of a download. To transfer data from one computer to another.
  • URL

    The Uniform Resource Locator is a unique identifier which describes the location, or ‘address’ of a piece of information or document, including the protocol used to access that information.
  • UXGA

    Ultra Extended Graphics Array is a display resolution of 1600 pixels horizontally by 1200 pixels vertically, usually only required in specialist applications.
  • Vector graphics

    These are programs that store images using computer algorithms to define shape, lines, animation etc.
  • Ventilation

    The airflow through a projector’s internal components which acts as a cooler for the lamp or light source.
  • Vertical frequency

    The rate per second, measured in Hertz (Hz), that the monitor draws all the lines on an entire screen and the higher the frequency, the less a flicker is produced.
  • VGA

    Video Graphics Array refers to the video display resolution standard of 640 pixels horizontally by 480 pixels vertically with up to 16 colours at a time and also allows for 320×200 resolution with 256 colours. Video Graphics Array use RGB data to transfer.
  • Video capture

    Capturing an analogue video source and converting it into a digital format.
  • Video conferencing

    A personal communication mechanism with audio and video content that can include graphics and data exchange.
  • VPN

    Virtual Private Network is a service offered by public carriers whereby the user is given a network that appears to be private but which is actually carried over a public network.
  • WAN

    A Wide Area Network is a communications network that uses devices such as telephone lines, satellite dishes, or radio waves to span a larger geographic area than can be covered by a LAN. The Internet is a WAN.
  • WAV

    This is a format for a digital audio sound file.
  • Web server

    A server that stores and retrieves HTML document and other resources using HTTP.
  • Webcast

    The delivery of a live or recorded broadcast over the web.
  • Wizard

    A user-friendly help file that guides the user through computer processes, applications and programs.
  • WXGA

    Wide Extended Graphics Array refers to the widescreen display resolution of 1366 horizontal pixels by 768 vertical pixels with an aspect ratio of 16:9, popular for LCD and plasma flat panel displays. Computer displays refer to a WXGA resolution of 1280×800.
  • XGA

    Extended Graphics Array refers to a display resolution of 1024 pixels horizontally by 768 pixels vertically.
  • Y-Splitter

    A cable or adaptor that enables a single output into two inputs or a single input into two outputs.
  • Zip

    Compression technology that compresses large files, such as graphics to other users over the internet. After the Zip file is downloaded, a decompression software program is required to ‘unzip’ the document.
  • Zoom lens

    A projector lens that allows the adjustment of focal length (image distance compared with size) without physically moving the projector.
  • Zoom ratio

    This is the ratio between the smallest and largest image a lens can project from a fixed distance. A zoom lens is not as ‘bright’ as a fixed lens and the higher its ratio, the less light output is emitted.


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