Broadcast glossary

Broadcast Glossary

A progressively scanned high definition video format with 1920 pixels and 1080 lines of data and a normal frame rate of 24 frames per second.

2K, 4K and 8K
These are formats of a resolution greater than HD. HD has a horizontal resolution of 1920 pixels whilst 4K has a horizontal resolution of 4096 pixels, for example.

This is a term commonly used to define a component digital video format. The details of the format are specified in the ITU-R601 standard. The numbers 4:4:2 denote the ratio of the sampling frequencies of the luminance channel to the two colour difference channels. Therefore, there are two samples of each colour difference channel for each four luminance samples.

4:4:4 is commonly used to define a high resolution component digital video format. The numbers 4:4:4 denote the ratio of the sampling frequencies of the luminance channel to the two colour difference channels. For every four luminance samples, there are four samples of each colour difference channel. 4:4:4 sampled signals are also available in a RGB format with equal sampling rates for each of the colour channels. A pair of coax cables are commonly used to carry the signal in according to the SMPTE 372M standard.

4Fsc is commonly used to define a composite digital video format. The details of the format are specified in the ITU-R601 standard. 4Fsc denotes that the sampling frequency is 4 times the colour subcarrier frequency (approximately 14.3 MHz for NTSC and 17.7 MHz for PAL).

A to D converter
An A to D Converter means Analogue to digital.

ADR stands for Additional Dialogue Recording which is the process of replacing actors' lines by re-recording in a studio.

AES, which is the Audio Engineering Society, is a professional organisation that recommends standards for the audio industries.

Informal name for an establishment created jointly by the Audio Engineering Society and the European Broadcasting Union organisations to set a digital audio standard. Other terms that apply to this standard are AES3, AES/EBU audio or simply AES audio.

AFD stands for Active Format Description.

An Afterburner is a device which translates embedded data from the video bit stream into human readable text. This text is then "burnt" into the on screen picture in character windows. This is usually time code data, scene, take and other post production data

Alpha channel
In Electronic production and post-production, there is increasing application of 4:4:4:4 encoding, which provides full-bandwidth R', G', and B' plus the additional alpha channel to carry processing information. An adaptation from computer graphics, the alpha channel may contain information for linear key, for luminance and/or chroma transparency, for variable edge enhancement, and similar image-processing information

Any signal that varies continuously as opposed to a digital signal that contains discrete levels representing digits 0 and 1.

Analogue Video / Analogue Audio
A video or audio stream encoded into the voltage amplitudes of an electromagnetic wave.

Level or intensity of Signal.

Aperature, camera
The maximum dimensions of the optical image available on the active surface of the photo-sensor, within which good quality image information is being recorded. The maximum usable scene information captured and introduced into the system is determined by the camera aperture, and also what is available for subsequent processing and display.

Aperature, clean
The clean apearture in a video digital system defines an inner picture area (within the production aperture) within which the picture information is subjectively uncontaminated by all edge transient distortions.

Aperature, production
A production aperture for a studio digital video signal defines an active picture area produced by signal sources such as telecines, digital video tape recorders, cameras and computer-generated pictures. It is recommended that all of this video information is carefully produced, stored, and properly processed by subsequent digital equipment.

Aperature, safe action
A safe action aperture indicates the safe action image area within which all significant action must take place, to ensure visibility of the information on the majority of home television sets.

Aperature, safe title
A safe title aperture indicates the safe title image area, within which the most important information must be confined, to ensure visibility of the information on the majority of home television sets.

An Artifact defect or distortion of the image, introduced along the sequence from origination and image capture to final display.

Aspect Ratio
The ratio of width to height in a picture.

ATC stands for Ancillary Time Code.

Audio Group
This is a group of four audio signals embedded into a serial digital video bitstream. This group usually consists of either two stereo pairs, or four monaural audio channels.

Average Picture Level (APL)
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.

Balanced Audio
Balance Audio is a method of sending a stable audio signal that resists interference by transmitting the signal and its electrically inverse signal. This cancels out any noise pickup as the two signals are differentially combined at the receiving end. This is particularly useful for long and/or exposed cable runs.

Bandwidth is the measure of the capacity of a circuit or channel, the amount of information transferred between points within a specified time period.

A Bit is a binary representation of 0 or 1. One of the quantized levels of a pixel.

BER stands for Bit Error Rate, This is the average probability of a digital recording system reproducing a bit in error. It is the ratio of the number of characters of a message incorrectly received to the number of characters of the message received.

Bit Stream
Bit Stream is the transmission of a continuous series of bits down a line.

Bit-rate is the speed at which bits are transmitted and is normally expressed in bits per second. With video information, in a digitized image for example, is transferred, recorded, and reproduced through the production process at some rate (bits/s) appropriate to the nature and capabilities of the origination, the channel, and the receptor.

Blanking level
This is the level of a composite video signal that separates the range containing picture information from the range containing synchronizing information.

BNC is a coaxial cable connector used extensively in professional television systems.


Boom is a microphone or lighting support set nominally parallel to the floor usually held by a vertical stand.

Bytes consisting of 8 to 10 bits per sample are typical in digital video systems.

Cable equalisation
Cable equalisation is the process of altering the frequency response of a video amplifier to compensate for high frequency losses in coaxial cable.

Caption is a term used for artwork, lettering or diagrams used in video programmes.

CCIR stands for International Radio Consultative Committee.

The CCU is the Camera Control Unit.

Chroma Key
Chroma keying is a technique which allows a vision mixer to substitute a saturated colour, normally green or blue.

The chrominance is part of video signal that conveys colour information.

Closed Caption
A Closed Caption is a system of encoding word characters into a video stream that can be decoded to allow subtitles to accompany the picture.

CODEC is an acronym of Compression, Decompression. A device or piece of software that translates one file or signal format into another, ideally with an undetectable loss of quality.

The cloud refers to remote services accessible via the internet.

Colour Bars

Colour Bars are specific strips of colour used to test image quality.

Colour Black
This is an analogue video signal that displays a black screen. This signal is often used as a reference signal for timing purposes.

Component Analogue
The non-encoded analogue output of a camera, video tape recorder, etc., that consists of the three primary colour signals: red, green, and blue (RGB). Together they convey all necessary picture information.

Component Colour
A structure of video signal that separates the R, G and B signals which can be achieved by separate channels or time division multiplexing, or by a combination of both.

Component Digital
A digital representation of a component analogue signal set, most often Y, B-Y, R-Y.

Composite Analogue
Composite Analogue is an encoded video signal such as NTSC or PAL video that includes synchronising information both horizontal and vertical.

Composite Colour
Is the structure of a video signal in which the luminance and two band-limited colour-difference signals are simultaneously present in the channel. This can be achieved by frequency-division multiplexing, quadrature modulation, etc.

Composite Digital
This is a digitally encoded video signal such as NTSC or PAL video that includes synchronising information both horizontally and vertically.

In post-production, conforming is when you re-link the edit sequence to the high resolution master media after a low resolution edit.

Coarse Wave Division Multiplexing allows a single optical cable to carry up to 16 separate channels of data using different wavelengths for each channel. The wavelengths are typically separated evenly at 20 nanometer wavelength intervals.

DARS stands for Digital Audio Reference Signal. This signal is used for synchronization in digital audio studio applications The DARS signal conforms to the format and electrical specification of the AES3 standard, but often has only the preamble active.

DAT stands for Digital Audio Tape.

dB FS is an abbreviation for "decibels full scale," a unit of power as measured by a digital device.

decibel (dB)
A customary logarithmic measure most commonly used for measuring sound. If one sound is 1 bel (10 decibels) "louder" than another, this means that to the human ear, the louder sound is 10 times louder than the fainter one.

De-embedding is generating two separate signals by extracting an embedded signal from an input stream.

A Degausser is a device used for reducing residual magnetism.

An abbreviation for 'de-multiplexing', Demus is the separation of multiplexed data streams for dispersal to different devices. This term is often used synonymously with De-embedding when used to describe the process of extracting AES audio that has been embedded onto a serial digital video signal.

This is the information sent as a series of high (1) and low (0) signals separated by a fixed period of time. Signals formed of series of coded pulses (numbers) as distinct from continuous analogue signals.

Digital Video / Digital Audio
This is the encoding of a video or audio stream using binary digits (1 and 0) instead of wavelengths and amplitudes.

Distribution Amplifier
A Distribution Amplifier is an electronic device that amplifies a broadcast signal and outputs the same signal many times. The essential function is a copying device.

A Downconverter is a converter which takes an HDTV signal and rescales it into a standard definition TV signal.

This is a broadcasting term which means closer to the point of final transmission.

Drop frame
This is a correction method of adjusting the nominal 30 frame per second counting rate of SMPTE 12M time code to the actual counting rate of approximately 29.97 frames per second, a difference of 1 part in 1001. This correction drops 108 frames per hour by skipping frame counts 0 and 1 at the beginning of each minute, except minutes 0, 10, 20, 30, 40 and 50. See also LTC and VITC.

DWDM stands for Dense Wave Division Multiplexing, it allows up to 80 separate channels of data to be carried over a single optical cable using different wavelengths for each channel. It is a method for combining multiple fibre-optic signals of different wavelengths onto one single strand of cable in a much smaller wavelength spectrum than CWDM.

EBU stands for European Broadcasting Union..

EDH stands for Error Detection and Handling and is a method of determining when bit errors have occurred along the digital video path.

Embedded Audio
Digital audio is multiplexed onto a serial digital video data stream according to the SMPTE 272M (standard definition) or SMPTE 299M (high definition) standards.

Embedding is combining two signals to allow them to be sent as one.

Electronic News Gathering

A protocol for connecting computers over a Local Area Network.

Fiber Optics
Fiber Optics is a method of allowing much higher transmission bandwidth than copper cable by encoding digital information into a pulsing laser.

A frame is a single stationary television or film image

Frame Synchronizer
This is a device which retimes an incoming video signal to a set reference such as genlock, bi-level or tri-level sync signals.
Gain is the ratio of amplification of attenuation usually expressed in decibels.

This is a Panasonic HDTV component digital video recording format that records on magnetic tape and uses data conforming to the ITU-R709 standard.

This is a Sony HDTV digital recording format that records on magnetic tape.

HDSDI stands for High Definition Serial Digital Interface. It is a bit-serial digital interface for HDTV component signals operating at data rates of 1.485 Gb/s and 1.485/1.001 Gb/s. The HDSDI interface is standardised in SMPTE 292M and can be carried over coaxial and fiber optic cables.

Hue is an attribute of a visual sensation according to which an area appears to be similar to one of the perceived colors, red, yellow, green, and blue, or to a combination of two of them.

Impedance is taking into account resistance and AC reactance, Impedance is a measurement of opposition to electrical current.

A digital signal can suffer from variation in timing and/or displacement, and Jitter is the measure of this variation. High Jitter can severely degrade the performance of an otherwise ideal system by introducing unwanted noise at the receiver.

When an image is sampled at one frame rate and converted to another the Judder is a temporal artifact that is associated with the moving images. As a result, motion vectors in the display may appear to represent discontinuously varying velocities.

A Keyer is a device which inserts data into the video bit stream based upon a supplied key signal. The data can be video/audio overlay, or broadcast data.

KeyKode is a system of latent edge numbers developed by Eastman Kodak. A similar system known as MR Code is used by Fuji Film. The numbers are machine and human readable and are located on the edge of motion picture film stock. They are used to number film frames during post production.

Letterbox describes a video signal that does not completely fill the screen vertically and therefore requires bars at the top and bottom of the image.

Logo Inserter
A specific type of keyer which inserts static or animated images or "bugs" into a video bit stream overlaying the image.

Linear Time Code or Longitudinal Time Code. A time and address control signal that is used in the professional video and audio industries. It provides an individual frame number for each video frame recorded and is typically written on a time code or address track of a video recorder.

Mux is an abbreviation of 'multiplexing' which is a way of joining two or more data streams for co-transmission over the same hardware.

NTSC stands for National Television Standards Committee. An analogue video format used as the broadcast standard for United States, Canada, Japan and several other countries. NTSC uses 525 lines per frame.

PAL stands for Phase Alteration Line. An analogue video format used as the standard for most European broadcasters and other parts of the world outside North America and Japan. PAL uses 625 lines per frame.

Panning is when you swivel a camera about a fixed axis.

When an image does not fill the screen horizontally, a bar is required on either side of the image to fill the screen.

A pixel is the smallest distinguishable and resolvable area in a video image, it is a single point on the screen. In digital video, a single sample of the picture.

ProRes is Apple Final Cut Pro's preferred codec. Typically, HD footage will be recorded at or transcoded to ProRes 422 (HQ) (at 176 Mbps VBR).

RCTC stands for Rewriteable consumer time code. It is a 8mm consumer time code written without reference to audio or video.

The number of bits determines the resolution of the signal.


RGB covers the three primary colour signals: red, green, and blue. When put together, convey all necessary picture information.

A router is a device with multiple inputs and multiple outputs which allows you to switch between video signals without the need for recabling.

RU stands for Rack Unit, it is a standard unit of measurement used for audio-visual equipment racks.

SAV stands for Start of Active Video. This is a digital synchronization sequence consisting of a sequence of four consecutive code words (a code word of all ones, a code word of all zeros, another code word of all zeros, and a code word including F (field/frame), V (vertical), H (horizontal), P3, P2, P1, and P0 (parity) bits.) which is used to designate the end of the horizontal blanking interval. The pixel immediately following the SAV is known as pixel 0 and designates the first pixel of the specific line of the digital image. See also EAV.

Scanning is the way the picture refreshes. The main two types are Progressive or Interlaced.

Serial Digital (SDI)
Serial Digital Interface is a standardised interface for transmitting digital television signals using a coaxial cable in serial form. A bit-serial digital interface for SDTV component signals operating at data rates ranging from 19.4Mb/s up to 540Mb/s. The SDI interface is standardised in SMPTE 259M, SMPTE 310M and can be carried over fiber optic and coaxial cables.

SMPTE stands for Society of Motion Picture and Television Engineers. SMPTE is a professional organisation that recommends standards for the film and television industries.

S-Video is a format in which a video signal is split into a luminance (brightness) component and a chrominance (colour) component.

Segmented frame is a method of transporting progressive HDTV images over an HDSDI interface. The picture is progressively scanned, however it is divided into two segments, containing the odd and even lines. These segments are then sent out the serial digital interface in the same way that the fields of an interlaced video signal are. This format is often used at nominal frame rates of 24, 25 or 30 frames per second.

TBC stands for Time Base Corrector which is a Short term signal store designed to reduce timing errors and litter in VTRs.

Time Lapse
Time Lapse is the recording of a single frame(s) with a time interval between each recording.

Unbalanced Audio
A method of transmitting audio over normal video impedance.

An Upconverter is a converter which records an SDI signal as an HDSDI signal.

User bits
There are 32 bits in time code that are user assignable. They are typically used to contain information such as date, reel numbers, scene and take numbers, or other user-oriented data.

Vertical Ancillary Data. Acronym for ancillary data packets carried in the active part of the lines which are during the vertical blanking interval of a digital television signal. May also refer to the data space located in the vertical blanking interval where these packets are carried. Ancillary data packets contain metadata associated with the video or audio of a television bitstream. See also HANC.

Program rating information encoded onto a broadcast video signal as an XDS packet in a Line 21 closed caption system. Television sets with V-Chip decoders will disallow viewing of programs if the rating is too high.

Vertical Interval Time Code. This time and address control signal standardised by SMPTE 12M is encoded on one or more lines in the vertical interval of standard definition television signals.

Video Graphics Array. This is a computer video adapter which can display 16 colours with a resolution of 640x480, or 256 colours at 320x200.

White Balance
White Balance is the process of removing unrealistic colour casts, so that objects which appear white in person are rendered white.

This is an effect in which one scene appears to push the other off screen.

Word Clock
This is an acknowledgement and transmission signal which enables a receiving system to adjust it's timing for incoming digital audio packets

eXtended Data Service. XDS involves a system of data packets sent with the broadcast which can deliver program rating information such as age-appropriateness, the current time or local weather reports.

A compressed bandwidth RGB signal. The video luminance (Y) is transmitted only once instead of once with each RGB channel, this requires more processing power at the receiving end, yet reducing the transfer rates by a third.


The zoom is the lens system with movable elements to provide adjustable magnification.