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Our broadcasting glossary can be found below, if you'd like to quickly jump to a section please use the box below;



A high definition video format which is progressively scanned with 1920 pixels and 1080 lines of data and a nominal frame rate of 24 frames per second (see also sF)


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.


A term 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.


A term 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 (analogue-to-digital)

A circuit that converts an analogue signal into a digital representation of that signal, using digital sampling.

AatonCode (AatonCode II)

An in-camera film timecode system which 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. The code is exposed during filming within the camera and specifically contains the production timecode synchronizing data, hour, minute, second, frame, year, month, day, production ID, camera ID and camera speed.


Audio Engineering Society. AES 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.


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.


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

There is increasing application of 4:4:4:4 encoding in both electronic production and post production---- which provides full-bandwidth R', G', and B' plus the additional alpha channel to carry processing information. The alpha channel is an adaptation from computer graphics, and 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.

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.


The ARRI code is an in-camera film timecode system. The code is exposed in the camera during filming and carries machine-readable data in the form of a modulated series of bars similar to SMPTE LTC for each film frame. ARRI Code specifically contains the production timecode data, hour, minute, second, frame, year, month, day, and camera ID.


A 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. Theatre screens generally have an aspect ratio of 1.85 to 1, widescreen TV (16x9) is 1.77 to 1, and normal TV (4x3) is 1.33 to 1.


Ancillary Time Code. See SMPTE RP188.

Audio Group

A group of four audio signals embedded into a serial digital video bitstream. The 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

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.

Bar Data

Bar data information is used to identify the precise unused areas of a raster image when the active image does not completely fill the raster. A particular example would be widescreen cinema material carried letterboxed in a frame with bars top and bottom. AFD and Bar Data are described in a forthcoming SMPTE standard as well as ATSC A/53E (2006), CEA CEB-16 (2006). See also AFD.


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

Bit error rate (BER)

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 Parallel

Byte-wise transmission of digital video down a multi-conductor cable where each pair of wires carries a single bit. This standard is covered under SMPTE 125M, EBU 3267-E and CCIR 656.

Bit Serial

Bit-wise transmission of digital video down a single conductor such as coaxial cable. May also be sent through fiber optics. This standard is covered under SMPTE 259M and CCIR 656.

Bit Stream

The transmission of a continuous series of bits down a line.


The speed at which bits are transmitted. This is usually 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

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


British Naval Connector, or Bayonet Nut Connector, or Bayonet Neill Concelman - a coaxial cable connector used extensively in professional television systems. A secure connection that locks in to limit the chances of disconnecting. These connectors have a characteristic impedance of 75O and are standardized by the IEC 169-8 standard.


A complete set of quantized levels containing all the bits. Bytes consisting of 8 to 10 bits per sample are typical in digital video systems.


Cable equalization

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


International Radio Consultative Committee. An international standards committee which is now known as ITU.

Cliff Effect

(Also referred to as the 'Digital Cliff') Often caused by excessive cable lengths, this is a phenomenon found in digital video systems that describes the sudden deterioration of picture quality due to excessive bit errors. The digital signal will be perfect even though one of its signal parameters is approaching or passing the specified limits. There will however be a point where the parameter will reach a point where the data can no longer be interpreted and the picture will be totally unrecognisable.

Closed Caption

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


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.

Colour Black

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 color

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

An encoded video signal such as NTSC or PAL video that includes synchronising information both horizontal and vertical.

Composite color

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

Composite digital

A digitally encoded video signal such as NTSC or PAL video that includes synchronising information both horizontally and vertically.


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.



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.

Daylight saving time (DST)

Daylight Saving Time (DST) is also known as simply as 'Summer' in many countries. It is a method of getting more daylight out of the summer days by advancing the clocks by one hour during the summer.

dB- (prefix)

An identification that a logarithmic scale has been used on a measurement similar to that of the decibel in that a difference of 10 dB- corresponds to a factor of 10. In each case, the actual measurement is compared to a fixed reference level r and the "decibel" value is defined to be 10 log10(a/r).


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.


Generating two separate signals by extracting an embedded signal from an input stream. This term is often used to describe the process of extracting AES audio that has been embedded onto a serial digital video signal.


An abbreviation for 'de-multiplexing' which 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.

Digital Video / Digital Audio

The encoding of a video or audio stream using binary digits (1 and 0) instead of wavelengths and amplitudes.

Distribution Amplifier

An electronic device that amplifies a broadcast signal and outputs the same signal many times. The essential function is a copying device.


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


A broadcasting term meaning closer to the point of final transmission. Indicates that you can confidently use the system for "on air" signals.

Drop frame

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.


Dense Wave Division Multiplexing 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.



Emergency Alert System. A warning system that is used in the United States that either interrupts normal broadcasting, or displays an alert which crawls across the video picture. These alerts also contain an audible alert message.


End of Active Video 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 start of the horizontal blanking interval of the digital line. See also SAV.


European Broadcasting Union. EBU is an organisation of European broadcasters that among other activities provides technical recommendations for the 625/50 line television systems.


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


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


Combining two signals to allow them to be sent as one. This term is often used to describe the process of inserting AES audio into a serial digital video signal.


See Cable equalization.


Fiber Optics

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

Film Time Code

See AatonCode, ARRI Code.

Frame Synchronizer

A device which retimes an incoming video signal to a set reference such as genlock, bi-level or tri-level sync signals.



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


A Sony HDTV digital recording format that records on magnetic tape.


High Definition Serial Digital Interface. 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.



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.


Key channel

See Alpha channel.


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.


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.


Matrix Time Code

See AatonCode


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



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.



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.


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


The smallest distinguishable and resolvable area in a video image. A single point on the screen. In digital video, a single sample of the picture. Derived from the words picture element.



The number of bits (four, eight, ten, etc.) determines the resolution of the signal. Eight bits is the minimum resolution for broadcast television signals.
4 bits = a resolution of 1 in 16
8 bits = a resolution of 1 in 256
10 bits = a resolution of 1 in 1024


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


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


Rack Unit. A standard unit of measurement used for audio-visual equipment racks. The Unit is 1.75 inches or 45mm.



Start of Active Video. 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.

Serial Digital (SDI)

Serial Digital Interface. 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.


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


Super-video or Component video. This is a format in which a video signal is split into a luminance (brightness) component and a chrominance (color) 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.


Time Code or Timecode

See Linear Time Code.


Unbalanced Audio

A method of transmitting audio over normal video impedance.


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.


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.