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Synonymous with ghosting; image retained when an object moves in an under-lit scene, lag is a low-light phenomena usually associated with tube-type cameras.  Appears as smearing or streaking of the video.


Local Area Network.  A network that connects computers in a small pre-determined area (like a room, a building, or a set of buildings). LAN's can also be connected to each other via telephone lines or radio waves.  Workstations and personal computers in an office are commonly connected to each other with a LAN. This allows them to have send/receive files and/or have access to the files and data. Each computer connected to a LAN is called a node.


See Videodisc.

Last Mile Services

Transmission services which link a customer’s premises with a common carrier’s point of presence. Usually used to describe land line or microwave links tying a customer’s premises to a broadband or high data rate transmission system such as a satellite uplink.


The factor of data access time due to disk rotation. The faster a disk spins the quicker it will be at the position where the required data can start to be read. As disk diameters have decreased so rotational speeds have tended to increase but there is still much variation. Modern 31/2-inch drives typically have spindle speeds of between 3,600 and 7,200 revolutions per minute, so one revolution is completed in 16 or 8 milliseconds (ms) respectively. This is represented in the disk specification as average latency of 8 or 4 ms.

Latent Image

The invisible image formed in a camera or printer by the action of light on a photographic emulsion. The image on exposed film prior to development.


1)The range of exposure a film stock can tolerate and still give substantially correct reproduction.  2) How far a person will go before blowing a fuse.


                         Transferring the finished audio track back to the master video tape.


A range of the levels in the data hierarchy of the video and system specification.


Making multiple recordings so as to place layers of graphics in a multi-element image.

LCD (Liquid Crystal Display)

A technology used in flat panel display systems.

LCD Panel

A panel which allows text and graphics information from a personal computer to be displayed onto a large screen or wall using a standard transmissive-type overhead projector as the light source. It allows large groups of people to view the computer display and images at one time.

LDP (Laserdisc player)

An electronic device which plays videodiscs.


The first part of a roll of film, or tape, that precedes the program material and contains alignment signals, test charts, ID boards, countdown etc.

 Legal Color Limiting

Method of clipping an electronic signal to conform to user defined maximum and minimum levels.


Image of a wide screen picture on a standard 4:3 aspect ratio television screen, typically with black bars above and below. Used to maintain the original aspect ratio of the source material.  When high definition television is shown on a standard 4:3 screen, it is considered to be displayed in letterbox.
See also: Side panels.


A range of allowed picture parameters and combinations of picture parameters.

Levels of Interactive Systems

Three degrees of videodisc system interactivity proposed by the Nebraska Videodisc Design/Production Group in 1980. They are: 1. Consumer model videodisc player- limited memory and processing power. 2. Industrial model with all the features of consumer model, plus on-board programmable memory and improved access time. 3. Qualities of 1. or 2. interfaced with an external computer and/or other peripheral processing devices.

Library Management System™(LMS)

A total integrated computerized system designed primarily for the storage, handling, and air-play of broadcast commercial segments. The LMS controls all devices, including the multi-cassette system and any external VTRs and peripherals, through a system application controller .

Limited Motion Codec

A picture processor or codec which takes full motion video information and reduces it to a series of video snapshots to be transmitted at a low data rate between sites. Does not include codecs which convey full motion video.


A type of compressor that restricts output from exceeding a preset level.


A means of preventing a signal from exceeding a specified peak value. This is most important: signals that exceed values that would cause over-modulation or over-deviation would be in violation of FCC rules and regs and would more than likely cause harmful interference and subject responsible parties to potentially large fines.

Line 21

The US standard for closed captioning uses Line 21 of the VBI-lines for transmission. The data rate is low and allows for recording and playback on a consumer VCR. A decoder/character generator combination in a set-top box or in the TV is used to display the captions.

Line Event

An event during which an external input signal is routed directly to the specified output channel. This is sometimes used to route the station "logo" to the output channel.  See Logo Event.

Line Pairs

A measure of resolution often used in film and print media. There is often confusion when comparing film and video lines of resolution. In film, line pairs are measured as the number of line transitions measured per millimeter or per inch. Vertical resolution is measured with horizontal lines. Horizontal resolution is measured with vertical lines (see Resolution). Diagonal resolution is measured with diagonal lines. In video, lines of resolution are a measure of the maximum number of line transitions perceived over the entire length or width of the picture screen.

Line Select

A feature of a waveform monitor permitting selection of any video line within a video field for display.


Term used to differentiate between A/V material recorded on tape (linear) which does not allow instantaneous random access to the recorded data and A/V material recorded on a RAID or other similar device which allows for instantaneous random (non-linear) access to the recorded data.

Linear Distortion

A video system suffers from linear distortions when it cannot transfer all the amplitude and phase properties of a video signal faithfully at all frequencies.  Typical linear distortions include peak overshoot, color smearing and brightness variances at edges of the display.

Linear Video

Any video program which plays from start to finish with no variation in sequence or pace of information presented.


A communications channel which ties together only two sites. A network is made up of many links.


A freeware version of Unix, Linux is becoming popular as a powerful, low-cost operating system for running servers.

 Liquid Gate

A system by which film is temporarily coated with a layer of liquid at the moment of transfer to reduce the effect of surface faults such as scratches. Originally a laboratory printing process, it is now also be available on telecines. Also known as “Wet Gate”

 List Management

Versatile control of a system by means of a list or lists of events each of which triggers changes.


Television that is transmitted as the event occurs.

Listing Service

Provider of programming content for turnaround channel(s)or Satellite Feed(s)


A software program for setting up and maintaining e-mail discussion groups.

LMS (Library Management System)  

A general term for an entire system which has been constructed using equipment to be controlled by an application controller.  A multi-cassette video-tape storage, material management and playback system.

Load Balancing

Content may be mirrored (duplicated) on multiple servers to enable faster access/response times for end users.  Load balancing systems manage user requests to the servers, selecting the server that will provide the best accessibility.

Load Window

Amount of time beyond which a change to a playlist can not occur because the event would be missed.

Location Manager

The TCS Location Manager provides location tracking of the barcodes attached to media.  It can display information related to the media, such as its barcode, media type, media format, home location, and current location.  It can also display a history of what the operator has done to that information during the current session. 

Logo Event

An event during which an external input signal is routed directly to the specified output channel. This is sometimes used to route the station "logo" to the output channel.  See Line Event.

Long Form

Products scheduled for playout that are listed in the Electronic Program Guide (EPG).  For example, movies, sports events, or specials.  See Short Form.

Long-Form Material

Main events/feature programs as opposed to interstitial/promo/spots (Short-Form Material).

Longitudinal Timecode (LTC)

Time code which is recorded on one of the audio tracks (typically audio track 2) or on a special address track of a videotape.  The time code is used to identify each frame of video for frame-accurate video editing.

Longitudinal Recording

This process of running the tape past a stationary head in a longitudinal and linear fashion.

Longitudinal Time Code

Code recorded on one of the audio channels or on the address track.

Loop Through

Passive loop through is typically on the rear of studio monitors, where the video signal is routed from the input connector by a wire directly to another output connector. Another video device can then be connected via a cable to this output connector. Active loop-through refers to these output connectors where video is terminated, buffered, amplified and regenerated as an output.


A video device (switcher, monitor, etc.) that allows video inputs to pass through outputs to other devices without terminating. By looping the signal through a device, one signal can drive several devices.

Lossless Compression

Image and data compression applications and algorithms which reduce the stored size of a data or graphic file without loosing critical data.

Lossy Compression

Methods of image compression, such as JPEG, that reduce the size of an image by eliminating some pictorial information. Lossy methods result in some image degradation, which is usually a factor of the degree of compression. The greater the compression ratio (more information removed), the more image degradation.

Lossy line

Transmission line that is designed to attenuate the signal put into it.  

Low Key

A scene is low key if the tonal range of the reproduction is mostly in the high density (shadow) range of the process and contains few mid tones or highlights.

Low-Pass Filter

A special circuit used in a variety of situations, from microphones and mixers to RF circuits, that block frequencies beyond a specified point.


Least significant bit. The bit that has the least value in a binary number or data byte. In written form, this would be the bit on the right.
For example: Binary 1101 = Decimal 13
In this example the right-most binary digit, 1, is the least significant bit-here representing 1. If the LSB in this example were corrupt, the decimal would not be 13 but 12.
See also: MSB.


Linear Time Code. Time code recorded on a linear analog track on a video tape. It is audible and can be read at high speeds, but not when the tape is still.


A measurement of light emitted by a light source at the point of emission.


The amplitude (brightness) signal component in video.  It is the monochrome portion of the video signal. It is often referred to as "Y".


The metric measurement of light intensity taken at the surface which the light source is illuminating. The measure of the total lumens falling upon a unit of area. 1 lumen per square meter. One footcandle equals 10.76 lux.

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