A

You’re Adorable

A (frame)

First video frame of a 3:2 sequence. This is used to convert film shot at 24fps to video running at 30fps.The A-frame is the only frame in the sequence where a film frame is completely reproduced on one complete video frame.

AAC

Abbr. Advanced Audio Coding - A lossy audio compression format that can either be MPEG-2 or MPEG-4 based. Designed as a successor to mp3 AAC it achieves higher sound fidelity than mp3 for a given bit rate and is referred to as 'transparent' or as good as the original at 128kbits for stereo and 320kbits for 5.1surround.

AAF

Abbr. Advanced Authoring Format was created by the AMW Association and is a specification for video post production and authoring. AAF uses structured storage and is designed to be a representation of works in progress. It can interchange two forms of data- 'essence' the actual audio, video or multimedia information and 'metadata' which describes how to modify the essence data.

AAL

Abbr. ATM adaptation layer. The AAL translates digital voice, images and data signals into the ATM cell format and vice versa. There are 5 layers specifying different uses, AAL1 is a constant bit rate, AAL2, a variable bit rate and AAL5 a data specific channel. All AAL’s allow for multiplexing to allow the use of virtual channels of data so increasing the traffic or payload

Aaton

Trade. French film camera maker pioneering timecode with film.

AatonCode

An in-camera film timecode system, exposed in the camera during filming, carries data which is both machine-readable (a matrix of dots for each film frame) and man-readable for its conversion into SMPTE time code. AatonCode specifically contains the production timecode synchronizing data, hour, minute, second, frame, year, month, day, production ID, camera ID and camera speed

A weighting

The most commonly used of a family of graphical curves to the measurement of sound pressure level. The others are B, C, D and Z. Originally intended for the measurement of low-level sounds (around 40 Phon), it is now commonly used for the measurement of industrial noise and environmental monitoring. A-weighting is also used when measuring noise in audio equipment, especially in America. In Britain, Europe etc Broadcasters and Audio Engineers more often use the ITU-R 468 which was developed in the 1960s based on research by the BBC

ABB

Abbr. Auto Black Balance. The camera will shut the lens completely and adjust itself to give no colour casts in the black areas and to reference the picture brightness levels. This should be done after a white balance

A-B Printing

FILM. Printing from original film stock which has been conformed into two rolls with alternating shots and black opaque leader. This methodology will eliminate any potential splice marks from showing up on prints and permits the incorporation of optical effects and titles. (Film Editing)

A-B roll

FILM. Originally a edit formed from 2 rolls of material, both interpositive copies that allowed scene transitions such as fades, wipes etc and are combined on an optical printer to a third master roll.

A-B roll editing

Video. Linear editing tape system using two source players running in sync allowing transitions to be recorded on a third master VTR. Frame accurate (with timecode) and repeatable edits are created by the controller and stored as an EDL file or edit decision list.

A-Wind

An indication of the emulsion position on a roll of film. An ‘A’ wind is a roll with the emulsion facing the centre of the roll

AB stereo

Normal stereo, two discrete (independent) channels of audio also known as left and right channels

A/B Switch

A switch that selects one of two inputs (A or B) for routing to a common output while providing adequate isolating between the two signals.

Above-the-line

Hierarchical budget division for non-technical, critical personal such as producers, directors and talent

Abrasion Resistance

Ability of a wire, cable or material to resist surface wear

Absolute Jitter

The variation in position of a digital signals transitions from one-zero relative to those of a synchronous stable reference

Absolute Zero

The coldest possible temperature. A point when all molecular movement ceases Zero degrees Kelvin as it is commonly expressed equates to minus 273.16 °C or minus 459 °F

absorption loss

attenuation of the optical signal within the fibre optic transmission medium. Usually specified in terms of dB/km.

AC-3

Abbr. Audio Coding 3. The technical name for Dolby Digital’s third generation surround system compressing 5 channels of high quality sound data into 384kbps. It uses six discrete audio channels, one each for front L/R rear L/R, centre and a low pass filtered (150hz) sub-woofer audio channel to form a 5.1 matrix.

AC

Abbr. Alternating Current. An electric current with continuously variable voltage that periodically changes polarity i.e. 60 times a second for 60Hz power. A method of power transmission

AC Coupled

A technique to remove the constant DC voltage component from an AC signal.

Academy Award®

Trade. An award (colloquially known as an ‘Oscar’) given annually by the American Academy of Motion Picture Arts and Sciences for what it considers to be the most outstanding film, performance or other creative or technical contribution of the year. The awards ceremony is held now in the Kodak theatre in Hollywood around Feb/march

Academy Format

A film aspect ratio of 1.37:1 The actual picture area is 21 x 15mm on the 35mm film. Commonly thought of as 1.33-1 this was the initial ratio defined by SMPE in 1929 but was adapted by the AMPAS in 1932

Academy Leader

A precise length of film (typically 12 or 8 feet) with timing, identification and synch information. Provides a numbered countdown (in feet or seconds) to first frame of picture.  

Access light

A light unit that emphasizes one subject. This might be a key light, a kicker, or a backlight. (Lighting)

Access

The retrieval of information from a storage medium such as a disk or tape

Access time

The amount of time taken to find, retrieve and use data after the initial command to do so. It is usually measured at its worst, i.e. the longest time it takes to get data from one section to another

Accumulated Charge

Light falling on a CCD or CMOS is converted into electrons. The resulting ‘charge’ accumulates and is read as an electrical value by a transistor. The charge is directly proportional to the light hitting the device.

ACI

Abbr. Adjacent Channel interference. Analog TV channel signal degradation i.e ghosting caused by high levels or over modulation of near-by signals.

ACID

Trade. Audio editing and mixing software from Sony

Acetate

FILM. Also known as a cell it is a clear sheet of plastic, formally cellulose acetate, and used for graphics or by animators to paint on

Acetate Base

The transparent cellulose acetate plastic film which was used as the backing for magnetic recording tape.

Acoustics

The science of the transmission of sound waves through divergent mediums and the interaction they have on objects.

Actualities

Events from the historical world used in news and sports programs.

Actualized Audience

The actual number of viewers of a program that offers interactive TV and are connected.

Actuator

Motor and arm used to move and align an antenna

AD

Abbr. FILM. Assistant Director. Despite the ‘director’ tag, this is more of a logistical than an artistic role: the assistant director is primarily responsible for ensuring that everything runs smoothly during the shooting, that schedules are kept to and that everyone is where they’re supposed to be. On larger productions, there may be grades of assistant director – usually, the second AD is responsible for supervising principal cast while the third AD handles extras and other background artistes.

ADAC

1990’s. Trade name for a ground-breaking television standards converter. Used a proprietary form a spatial and temporal interpolation to convert the different frame sizes and frame rates.

Adaptive channel Allocation

The channel’s information-handling capability is not fixed but assigned on demand

additive key

Method of keying in which two complementary video signals that have already been shaped with a key signal are added to create a composite image without attenuation.

additive mix

Addition of two video images together without attenuation of either signal. The brighter parts transition first and remain longest.

ADC

Abbr. Analogue to digital converter. Device that encodes the proportional electrical signal into a binary (One, zero) representation. The digital signal is expressed in terms of bit depth – the various levels of the signal- and the sampling- the number of times a second the signal is inspected.

Additive colour

Primary colours of Red, Green & Blue when added together in varying proportions can form all the colours we see. White light is a blend on 38% red, 51% green and 11% blue for instance

Additive White Gaussian Noise

Random radio noise characterized by a wide frequency spectrum that is continuous and uniform over a frequency band.

Address code

FILM. A small electronic signal that is added to each frame marking it and this identifying it with a specific address.

Ad-lib

Un-scripted or unrehearsed speech or action

ADPCM

Adaptive Differential PCM is a pulse code modulation technique that samples and represents an analog waveform at precise sample times or ‘pulses’ Adaptive modulation varies the sample time periods so allows for data reduction.

ADM

Adaptive Delta Modulation. Digital coding method employed by Dolby Labs’

Admittance

The measure of the ease with which an alternating current flows in a circuit. The reciprocal of impedance.

ADR

Abbr. Automated dialogue replacement. Used to replace or improve low quality voiced sound in post-production and synchronizes the speech with the lip movement. Not always automatic. Also known as ‘looping’.

ADSL

Abbr. Asymmetrical Digital Subscriber Line is a data communications technology that enables relatively fast data transmission over conventional copper telephone lines. With ADSL a single phone line can be used simultaneously for voice calls and data transmission. ADSL differs from DSL in that data download speeds are normally greater than upload speeds and is therefore said to be asymmetrical.

ADTV

Abbr. Advanced definition TV. Forerunner to the HDTV standard

Aerial Shot

An extremely high angle view usually taken from a crane or helicopter.

AES

Abbr. Audio Engineering Society. AES is a professional organisation that recommends standards for the audio industries including the universal digital audio transport scheme with the European EBU.

AES/EBU

Abbr. Informal name for a digital audio standard established jointly by the Audio Engineering Society and the European Broadcasting Union organisations. This audio standard is formally known as AES3 but may also be informally called AES/EBU audio or simply AES audio

AFC

Abbr. Automatic frequency control. A circuit which locks an electronic component onto a chosen frequency, usually by measuring a feedback loop and detecting the resultant gain output.

AFD

Abbr. Active Format Description. AFD is intended to guide DTV receivers and/or intermediate professional video equipment regarding the display of video of one aspect ratio on a display of another aspect ratio. It is specified by SMPTE standards 2016-1 and 2016-3. Also known as WSS.

Afterburner

A device which takes embedded data from the video bit stream and translates it into readable text which is “burnt” into the picture in a character windows. This is usually time code data, scene, take and other post production data

After effects

Trade. Editing and compositing software used to create visual effects from Adobe.

AGC

Abbr. Automatic Gain control. An electronic amplifier used to regulate levels within a certain limit usually by referencing the amplitude with a reference signal or synchronising signal.

Affiliate

A TV station, not owned by a network, that grants a network use of specific time periods for network programs and advertising, for compensation. Remainder of broadcast day is programmed locally

AFM

Audio frequency modulation. A high quality audio recording system in which digitised audio data is modulated on an FM carrier.

AFTRA

Abbr. American Federation of Television and Radio Arts – talent union

AIFF

Abbr. Audio Interchange File Format, a common format for storing and transmitting sampled sound. The format was developed by Apple Computer and is the standard audio format for Macs. AIFF files generally end with a .AIF or .IEF extension. The AIFF format does not support data compression so AIFF files tend to be large. However, there is another format called AIFF-Compressed (AIFF-C or AIFC) that supports compression ratios as high as 6:1

Aircheck

The recorded copy of an aired broadcast to confirm transmission.

Air Spaced Coaxial Cable

One in which air is the essential dielectric material. A spirally wound synthetic filament or spacer may be used to center the conductor

ALE

Abbr. Avid Log Exchange. A file format used to exchange edit data between Avids. Can also be used by third party equipment like logging systems and other NLEs to input EDL data into an Avid.

Algorithm

A formula or set of steps used to simplify, modify, or predict data.

Aliasing

An artefact produced by insufficient sampling, incorrect representation, or beyond the limit of resolution. Often affecting the higher frequency information resulting in a bias of low frequency information or aliases. We see such artefacts for instance on curves, which may appear ‘staircased’ instead of smooth.

Alignment

Method of maximising a signal by moving and correctly pointing an antenna

All inputs hostile

Measurement technique, particularly for crosstalk, using worst case conditions (typically, full chroma signal on all inputs other than the one under test).

All ones

A digital signal consisting of data that contains all logical ones. In telecommunications, a test signal consisting of 11111.

Alpha Channel

Also known as a key channel An adaptation from computer graphics, the alpha channel isn’t a part of the active picture but may contain information for transparency of the image to allow high quality layering

Alphanumeric

A display symbol set consisting of the twenty-six letters of the alphabet and the digits 0 through 9.

Ambience

Background sound

Ambient Light

General, non-directional, room light

Ambient noise

Total background sound

AM

Abbr. Ante meridiem.  Morning

AM

Abbr

AMII

Abbr

AMOL

Abbr. Automated measurement of Line-ups. The technology which allows Nielsen Media Research (NMR) to track an identification code within locally transmitted TV signals for network and nationally syndicated programs. NMR is also linked by computers to networks and syndicators in order to receive their latest schedule changes. Using this technology, NMR can pin down exactly what program was shown on what channel at a particular time.

Ampp

Abbr.

Ampex

The inventors of the VTR and once a major manufacturer. The name stands for ‘Alexander M Poniotoff for Excellence

Amphenol

Trade. Connector manufacturer

Amplified gain

Gain is the ratio of the amount of power you can reach in one direction from the antenna to the amount of power that would be generated if the power radiated equally in all directions from the antenna. It is expressed in decibels, or dB.

Amplifier

A circuit that increases the voltage or power of a signal. The amplification or GAIN is usually expressed in db’s. A 3db gain is proportional to the doubling of the power

Amplitude

The height or magnitude of a signal in voltage or current. Frequently expressed in terms of peak, peak-to-peak, or RMS The height of a signal when expressed on a waveform monitoring device

Amplitude Distortion

Unwanted harmonic errors in the modulation of the carrier which affect the quality of the signal. Voltage fluctuations or circuit power changes are the usual cause.

Amplitude modulation

A transmission system in which the original signal waveform is made to vary the carrier amplitude. The changing ‘height’ or amplitude is directly proportional to the original signal voltage. By decoding the height of this signal when comparing to a pure sine wave (pure carrier of the same frequency) the signal can be reconstituted back to the original analogue signal.

Amplitude shift keying

A modulation technique that represents digital data as specific amplitude. Using a pure analogue wave carrier or more commonly a light wave of fixed frequency. In its simplest form if the wave is ON, then this represents a binary 1, if the wave is absent, this represents a binary 0.

Anaglyph 3D

Early and popular form of 3D utilizing two images, one red, the other cyan (These colours are ‘opposite’ each other and thus cancel each other out) superimposed on one another. The images are not registered, and as such mimic the eyes recreating an illusion of depth. The eye then sees red as white, and cyan as black through the red lens- the brain does a lot a processing to extrapolate ‘colour’ Some systems use green filters (cheaper to make) but the effect is not as pleasing as the colours appear less natural. Generally the red eye is the left .Another ‘advance’ was made by adding a corrective ½ dioptre lens to the red glass to compensate for the innate difference the eye has in focussing divergent colours. A simple trick to wear low power corrective lens and the filter glasses sees an improvement of relative sharpness. New style 3D glasses use polarizing filters to block one image but this leads to a darker overall picture.

Analog TX (Analogue)

Analogous – Meaning similar relationship.  A mode of transmission that uses a continuous, proportional system- either amplitude or frequency to describe the original signal voltage information. An analogue waveform has a physical similarity with the source it represents.

Analog Audio

A sound that has been converted into a continuous electrical signal whose amplitude and frequency is directly proportional to the original sounds loudness and frequency. Audio signals are measured in decibels and used in relation to the voltage in the signal or dbV. As an electrical system it has impedance which must be matched by the receiving decoder. A signal created by a microphone has an impedance of 600ohm; one from a CD has a line level or 20,000 ohms. Mis-matching can result in distorted sounds or very low, noisy sound

Analog recording

A method of storing audio signals as a continuous wave, using the original sound signal to modulate an electric current, which then creates a magnetic field if applied to a coil of wire- or ‘head’. This when passed close to a recording medium, such as iron oxide can store this magnetic footprint and be reconstituted by using the reverse process

Analog TV

Picture and sound information are transmitted through the air ( terrestrial) on a fixed carrier wave of precise frequency ( ie Channel 9) on which the TV pictures and sound change or ‘modulate’ the carrier proportionally to the brightness and loudness of the original signal. The carrier waves transmitted are in the VHF and UHF frequency bands. Adjacent channels are polarity separated either Vertically or horizon-tally to reduce adjacent channel interference and maximize bandwidth. Atmospheric conditions can affect these signals causing noise and also changes in brightness or the colour information. NTSC uses a tint control on the TV set to compensate for these errors, whereas PAL signals use a delay signal which automatically aligns the signal

Analog Channel

A communications path that carries voice or video in analog form — as a varying range of electrical frequencies

Analog component
Y Pr Br

High quality colour TV picture comprised of 3 signals, Y, a luminance, and R-Y and B-Y colour difference signals. To differentiate a digital component signal, CCIR refer to analog as YPrPb, and digital 601 as YCrCb. Both use the same colour space, however the analog signal uses 3 cables. A colour picture requires RGB information, However to transmit RGB would require a very large bandwidth. Component signals reduce this by mathematically cancelling out the brightness detail from 2 of the signals, the red and blue, leaving just the green or Y, which can then be reconstituted by the TV. Hence the shorthand form for component Y, R-Y, B-Y The difference between component and RGB is that it represents colour (G) as brightness (Y) and two colour difference signals, while RGB represents colour as level and saturation of red, green and blue. A synchronising signal is sent with the luminance information.

Analog component recording

Based on the technique of analog recording (see below) but retaining the separate colour difference signals actually in the recording. A component recording would thus require 3 stripes on the video tape for each field of picture information. However, the colour difference signals R-Y, B-Y are low bandwidth requiring less space than the Y information Sony invented a technique call Compressed time division multiplex CTDM for its BetaCam system which essentially speeds up the chroma signals and allows them to be recorded R-Y then B-Y on the same video stripe. The signals require a large memory or time base corrector to replay the image correctly. Component images are higher quality than composite and don’t suffer from patterning caused by the superimposition of a colour carrier but can suffer from chroma delay.

Analog Signal

A signal that encodes voice, video, or data into constantly variable voltage amplitudes. It can be transmitted over wire or when modulated on a carrier wave over-the-air. Such signals have a background level noise, that when copied can degrade.

Analog Spectrum

Range of frequencies used for radio and television transmission and defined by the world standard specification from ITU.

AM 120hz–2ghz. FM 88-110mhz, VHF100-250mhz UHF 480-900mhz

Analog video Composite

Brightness or luminance (Y) information that is encoded into a series of electrical voltages 0.3v – 1v The image is divided in to a block of scanning horizontal lines which can be reconstituted on a TV screen by including synchronising pulses where voltage drops to zero for a defined period both at the end of each line and at the end of each block or field- know as blanking. The display rate is 25-30 frames per second, with each frame divided into two equal fields. These are interleaved together on the display to reform the original picture. Colour was added by superimposing an AM carrier had two colour difference signals (derived by subtracting the green or Y signal from the red and blue) positioned- or phased- at different points on an AM carrier wave. A video signal, also referred to as baseband is at a frequency of 5-10mhz

Analog video recording

The video/audio baseband signal has a high DC component and a low ratio between black and white frequencies and cannot easily be recorded onto magnetic tape for storage. So, the baseband signal is used to modulate an FM carrier to improve the signal ratios and quality. The FM signal which also includes the colour AM carrier in turn modulates an electrical current that can be magnetically laid onto an iron oxide tape. To replay correctly the speed on the tape must be accurately reproduced. This requires the use of tape speed sync pulses or a ‘control track’ which are recorded with the video information. Audio is generally recorded as a separate linear track underneath a video track that is slanted. This slant improves the writing speed and uses a technique called azimuth recording (see below) to improve packing density and quality. A video stripe on the tape is one field

Anamorphic

FILM. Special lens used on film cameras that compresses the optical image horizontally, resulting in a ‘squeezed’ look. When decoded by a reverse lens the film would give an impressively wide field of view. Used on ‘epic’ motion pictures to immerse cinema-goers. It has the aspect ratio of 1,85-1 as the film format but due to the higher horizontal magnification this results in a 2,35-1 projection ratio.

Ancillary Data

Underlying, subordinate, secondary or subservient data relating to metadata, subscriber systems or interactivity.

Ancillary Time Code

Digitised Timecode packetised in the in video data stream on TV line 6

Angle of View

Also known as Field of view. The relative area visible by the camera lens

Answer Print

The first print combining picture and sound which is submitted by the laboratory for the customer’s approval

Animation

The process of making inanimate objects move. Done by drawing multiple pictures that when shown in a sequence at a speed greater than the eyes persistence of vision, give the illusion of movement. Models can also be used.

ANSI Lumens

Abbr. American National Standards Institute has established the standard for measurement of perceived brightness, or LUMEN

Antenna (aerial)

A rigid shaped metal device capable of amplifying the original signal input and used to transmit or receive radio waves.

Antenna Dish

Basically a passive amplifier. It’s parabolic or conical shape focus radio waves to increase the relative strength or ‘gain’ of the signal much as a magnifying glass increases the relative strength of light. The gain is expressed in db’s. The larger the dish the more ‘gain’ but also the more directional the antenna becomes, meaning it has to be more accurately pointed at the source or destination.

Antenna gain

A measure of the change in an antenna's signal power amplification based on orientation or signal direction.

Antenna gain

The amount of inherent signal gain of the antenna due to its focusing ability. Expressed as dbw increase where 3dbw is twice the equivalent input power

Anti-aliasing

Refers to the adding of additional images information so as to convince the eye that it sees something that cannot be represented digitally. Particularly apparent on curved or diagonal lines that cannot be represented smoothly or in the proper position because the display device resolution is not sufficient to represent them accurately. In practice, the eye is fooled, ‘jaggies’ are blurred and averaged out and the effect is psychological

Aperture

Diaphragm metal blades within a lens used to reduce the amount of light falling on the focal plane or sensor. Reducing the aperture also has the affect of increasing the depth of focus. Usually referred to in focal or F-stops. Each ‘stop’ number representing a cut of ½ the light level. F-Stops are logarithmic, and the smaller number corresponds to a larger aperture. F-stop is a product of the lens front element width and the focal length and isn’t always an actual definitive value of the light passing through the lens. A T-stop or transmission stop is used to describe the actual amount of light reaching the focal plane

Aperture

A cross sectional area of the antenna which is exposed to the satellite signal.

Aperture corrector

An electronic circuit that increases the apparent sharpness of a picture by adding electronic ‘peaking’ to contrast transitions. This helps to compensate for the finite size of a scanning beam or a pixel. VAC adds vertical peaking which looks subjectively more natural than horizontal ringing or HAC

APII

Abbr. Application Platform Interface is core middleware, a series of functions that programs can use to make the operating system perform specific tasks. APIs can allow for faster development, since programming to a device’s API is designed to be easier than programming directly to a device. APIs can also allow you to program without having intimate knowledge of the device or software.

API

Abbr.

APID

Abbr. Audio Packet I.D. A 13 bit metadata packet that identifies the a specific audio channel in the multiplexed transport stream

APLL

Abbr. Average Picture Level. In video systems, the average level of the picture signal during active scanning time integrated over a frame period; defined as a percentage of the range between blanking and reference white level

Apple

Edible fruit. One a day keeps the doctor away

Apple

Trade. Computer design and software company based in California.

Applet

a small application. For example, a Java interactive animation applet could be included within a web page or television enhancement if the user platform includes a Java run-time engine

Appletalk

Trade. relatively low-speed network defined by Apple Computer and integral to its machines

Apogee

The point in an elliptical satellite orbit which is farthest from the surface of the earth. Geosynchronous satellites maintain circular orbits around the earth at about 22,000 miles. Satellites move in a flat ‘figure-of-8’ shape, the apogee represents the top position of the ‘8’, the perigee is the closest point or the bottom of the ‘8’ shape path.

Apstar

Trade. Asia-Pacific Star. Name of the Chinese satellite system which carries commercial video services in the region.

Arabsat

Trade.. Arab Satellite Organization headquartered in Riyadh, Saudi Arabia. It provides telecommunications services for the Middle East region and operates C, Ku and Ka band satellites.

Arc

Movement of the camera in a curved direction

ARC

Abbr. Aspect ration converter. A device that converts 4:3 ratio material to 16:9 ratio material

Architecture

Logical design of a system, be it a switch, core system or whole station

Archive

Off-line storage of video/audio onto back-up tapes, RAID drives, optical disks etc usually as a file ready for scheduling

Arri

Trade. German camera and lighting manufacturer Arnold and Richter

ArriCode

An in-camera film timecode system, exposed in the camera during filming, carries machine-readable data –a modulated series bars similar to SMPTE LTC for each film frame.

Art Director

The Production Designer’s right hand. They speak with the construction coordinator about building the sets, stay on top of budgeting, and make the Production Designer’s vision a reality

Artefacts

A defect or distortion of the image such as blocking or pixilation made during the digitization process. Commonly associated with lower bit-rate or ‘compressed’ material where a change in video or audio level cannot be described in the applied data rate.

Artificial Light

A source of light created by lighting equipment, rather than from natural or reflected sources. Various forms exist, such as Tungsten light which has a white colour temperature of 3600K, or HMI which has a ‘daylight’ white colour of  5400K

ASA

Abbrr. American Standards Association. Specification which denotes the film or sensors sensitivity to light. Now referred to as ISO or International Standards Organisation.

ASCII

Abbr. American Standard Code for Information Interchange

A standard code used extensively in data transmissions, in which 128 letters, numerals, symbols, and special codes are each represented by a binary number.

ASF

Abbr. Active Streaming Format. Windows Media file format ending with the extension .asf. Used for delivering streaming video and is optimized for limited-bandwidth situations.

ASI

Abbr. Asynchronous serial interface. Transmission standard defined by the digital video broadcast (DVB) used to connect video delivery equipment within a cable, satellite, or terrestrial plant. High quality with high bandwidth capabilities ASI streams are usually compressed multiplex video data. Data rates are up to 188mbits

ASI over IP

Abbr. ASI video data standard, albeit at lower maximum data rates that has been meshed into the Internet Protocol standards to allow its transmission over much greater distances, or as a packetised file

Asiasat

A satellite system covering the Asia mainland.

assignment editor

one of the principal people on a news desk (hierarchies vary). An assignment editor keeps track of what’s going on in the newsroom’s coverage area, maintains an outlook for the day, the look ahead for tomorrow, and the futures file.

Astrovision

Trade. Variant of the 70mm film usually projected on a dome using 10 perforations per frame to guide it at 24fps

ASX

Abbr. Active Streaming eXtension. Windows Media file format ending with the extension .asx. This is a metafile which works in conjunction with ASF files for delivering streaming video.

Aspect ratio

 A term used to define the shape of the screen, presented in the form width:height  All standard (non-widescreen) televisions have an aspect ratio of 4:3 (also described as 1.33:1 and misleadingly Academy ratio), meaning 4 units to 3 units. British and many European widescreen films have an aspect ratio of 1.66:1, US and some European widescreen films have an aspect ratio of 1.85:1 and anamorphic widescreen films are usually 2.35:1. Widescreen televisions have an aspect ratio of 16:9 or 1.77:1, roughly halfway between the two standard widescreen ratios

Asperity Noise

Errors induced into the recording or playback by the minute imperfections of the recording surface and forma a part of the overall background noise

Assemble editing

Video. Editing of shots onto tape whilst also adding the control track and tape synchronizing pulses.

Associational Editing

The juxtaposition of images in order to present contrast, comparisons or ideas

Aston

Trade. Character generator. An on-screen overlaid graphic, usually giving the name of the speaker, reporter or place in vision. Name derived from Aston Broadcast Systems Ltd

Astra

Trade name for satellites operated by SES

Asymmetrical compression

Compression system that requires more processing power to compress the image, than to retrieve it. An example is an audio CD.

ATM

Abbr. Asynchronous Transfer Mode A data transmission scheme designed for live video conferencing and high rate data transfer over large distances using low jitter, small, self-routing packets of 53 bytes cells- 48 of which are available for user data It can operate in the Gigabits/second range, but mostly used for services under 622m/bits services like ADSL data links. See AAL above.

Atmos

Abbr. Atmosphere. Background audio recording

ATR

Abbr. Audio tape recorder

ATSC

Abbr. The Advanced Television Systems Committee

Formed in the early 1990s its name to set the digital television transmission standard that will replace the ageing NTSC standard. ATSC standards specify the technical transmission requirements for picture resolutions up to 1920 x 1080 pixels on existing 6mhz bandwidth VHF and UHF channels using MPEG-2 video and Dolby Digital audio compression on a digitally modulated carrier

ATSC-M/C

Abbr. Advanced Television Systems Committee-Mobile/Handheld promotes a technical standard that uses MPEG-4 or H.264 compression for transmitting video, audio and data to mobile devices in the USA.

Audible Spectrum

Frequency that lies between 20 and 20,000 Hz it produces a sound which is apparent to the average human.

Audio crosspoint

Physical path of a circuit that connects to inputs or outputs

Audio DA

Audio distribution amplifier A device used to replicate an audio signal each of which is identical to the input signal. Performed digitally, even though the outputs maybe analogue

Audio Description

A narrative soundtrack that describes what’s happening on screen

Audio descriptor

Service for the visually impaired superimposing text to describe or translate the audio content of the programme

Audio control booth

Room housing the technical equipment needed to monitor and control an audio signal. Usually acoustically isolated and altered.

Audio Follow

A vision control switcher that automatically changes the accompanying audio signal

Audio Insert

A feature that allows the changing of audio material without picture information.

Audio mixer

A sophisticated device that allows audio signals to be monitored, adjusted, controlled, modified and combined or ‘mixed’ with other audio signals. Generally modular in design the device can adjust the volume (either ‘trim’ an input of ‘fade’ a level), the ‘EQ’ or character of a sound, be copied and sent to other destinations or devices to modify further.

Audio sweetening

A term used to describe the changing of the character of the original sound by adjusting its equalization or dominance of certain frequencies within the original sound. Manipulation of the sound to create effect.

Audio Subcarrier

The carrier between 5 MHz and 8 MHz containing audio (or voice) information inside of allocated video bandwidth. These can be used for talkback, IFB and are not subject to the delay when digitized or compressed. Usually 256khz in bandwidth

Audio Synchronizer

Device that follows film timecode and translates that to physical movement of an audio tape or latterly to audio code laid onto tape with the audio signals

Audio Track

Video. Specific part of the tape footprint that is allocated to the audio component. Initially it was an analogue audio track located at the edge of the format and allowed jogging and shuttling of the sound during edit. Now it is usually specific data segments within the data field.

Audio timecode

Timecode identification signal used on tape that can be located in jog and shuttle modes. It can be heard as high pitched bleeps

Audience duplication

The extent to which the audience of one station is exposed to that of another.

Audience Flow

A measure of the change in audience during and between programs. Audience flow shows the percentages of people or households who turn on or off a program, switch to or from another channel, or remain on the same channel as the previous program.

Auslan

Australian sign language

auteur theory

Suggests that it is the director is the author of a film, much as a write is the author of a book.

Auto-conforming

Older style system. Off-line edit EDL (edit decision list) and the original rushes tapes are taken to a broadcast quality editing system for re-compilation automatically.

automatic changeover switch

Equipment that monitors the outputs of two sync generators (one in-use and one backup) and automatically switches to the backup sync generator should there be a failure of the sync generator in use.

AutoCue

Trade. Prompting system using a half silvered mirror and computer screen to superimpose scripts on the eye-line of the studio talent

Auto-Focus

Electronic circuit controlling small motors within the lens that looks at contrast edges within the picture to determine in the lens is focused.

Automatic Slating

Attachment which records the film shot and take numbers with a visible sync mark corresponding  to a pilot tone fed from an audio recorder.

Autotiming

Capability of some digital video equipment to automatically adjust input video timing to match a reference video input, thus making the signal synchronous for mixing etc..

Aux bus

A single crosspoint bus, typically used in conjunction with a production switcher. Often used to feed a digital picture manipulator with the same inputs as the primary inputs applied to the switcher

Aux Bus Audio

Abbr. Auxiliary Bus. A separate path which has an independent and controllable feed from each input channel. It can perform independently of the main mixer allowing signals to be combined in different ways..

Auxiliary loop

Sends a signal from the auxiliary output bus to a signal processing device such as a reverb generator, then brings the output of that device into an "auxiliary return" bus (thus creating a loop from the desk to the device, back to the desk). Also known as send/return

Attenuation

A decrease in the magnitude of a signal. The opposite of amplification

Attenuator

A passive device that decreases signal power.

Avalanche photodiode

Electronic device used as a detector in some fibre optic transmission systems.

Average audience

Estimated number of people who watch a program or station for a minimum of five minutes within a specific quarter hour.

AVO

Abbr. Announcer voice-over. Announcer reads a script (often but not always live) over pictures. When there’s a clip,

AVI

Abbr. TRADE. Audio Video Interleave. A file type that contains audio and video information. The AVI file is a ‘wrapper’ which encapsulated the actual video file into data blocks or ‘chunks’. Developed by Microsoft, and based on a Resource Interchange Format (RIFF) the chunks are used to describe the data- metadata, what codec is used to compress the video file. In this way it is not a specific video file, as the video information it encapsulates can be JPEG, MPEG, REALV, QTime, MPEG4 etc. As such to play an AVI file may require access to different codecs.

Avid

TRADE. Manufacturer of Non-linear Edit systems for broadcast and news production.

Axis

Imaginary line through a scene. As a general rule, the camera should stay on one side of the axis to prevent (e.g.) two people in separate shots from appearing to look in the same direction while speaking, instead of one facing right, and the other left.

AWB

Abbr. Auto White Balance. The ability to correct the white colour temperature balance in different lighting conditions. Natural light has a different white colour to artificial light. A sensor circuit measures the proportions of R,G and B when the camera points at a white object to determine the correct colour.

AWG

Abbr. American Wire Gauge. Standardization for wire sizes

AZ/EL Mount

Abbr. Azimuth/Elevation. Antenna mount that requires two separate adjustments to move from one satellite to another. One left to right or horizontal plane, the other up/down or in a vertical plane

Azimuth

The angle of rotation – in a horizontal plane. It is defined with respect to due north and can be thought of simply as a light-right movement of the antenna

Azimuth

Any magnetic head has a gap where the two magnetic poles meet. This is known as the 'gap'. The angle the gap makes with the direction of tape travel is known as the azimuth. It is normally 90º in analogue audio decks, or slanted for video recording devices

Azimuth recording

A technique pioneered in domestic video machines but also used in broadcast. The two video heads on the drum have their azimuths offset with respect to one another and thus reduces interference so the recorded ‘stripes’ can be closer together and reduce size