Video Glossary H-L

Video Glossary H-L 2017-08-07T00:33:43+00:00

Hard drive — Spinning magnetic disk generally inside a computer. The hard drive stores and retrieves data and computer programs.

[12]

Hard light — Light that makes sharp shadows, like from a bare bulb. [9]

Hardline — Special low-loss wire used principally by cable TV companies for long cable runs. [15]

HDSL — High Speed Digital Subscriber Line, a DSL with 750kbps two-way service over two twisted pair. [20]

HDTV (High-Definition Television) — Proposed method of displaying sharper, wider TV pictures than the present NTSC system. Pictures would be shaped into a 16:9 aspect ratio, composed of 1,125 scanning lines, each line having 1,920 pixels. [21]

Head drum — Shiny cylinder inside a VCR to hold the spinning video heads. [16]

Head end — The place where the cable TV company sends its signals from. This is not necessarily where its offices are or where its studio is. It is the center where the signals start their journey down the web of wires to homes. [4]

Head switching noise — A small horizontal discontinuity at the bottom of the TV picture (usually off the screen) caused when each spinning video head leaves the tape and the twin head takes over. [5]

Head — Top part of a camera tripod that holds the camera. [6]

Head-cleaning cassette — A cassette loaded with a ribbon of material (it could be cloth) which cleans the video heads as the cassette is played. [16]

Headphone — Muff-type earphones to fit over your head. Also the socket into which such phones are plugged, either on a VCR, mixer, or other audio device. [10]

Helical scan — The method of recording a video signal diagonally across the tape by winding the tape in a spiral around a rotating drum with video heads on it. [5]

Heterodyne — Method of time base correction used with common and color-under VCRs, yielding medium resolution pictures. Also, the type of VCR using the color-under recording method. [15]

Hi band VTR — Video recorder capable of recording full-fidelity color signals (as opposed to color under signals). [5]

Hi Z — High impedance, not terminated: not 75. An input ready to loop a signal to somewhere else. [2]

Hi Z — In audio, an input or output having 1000 or more ohms of impedance (resistance to signal flow). [10]

Hi8 — Much improved version of 8mm, downwardly compatible with it. [5]

Hidden line wireframe — More complex, more realistic wireframe where wireframe lines disappear if part of the object they’re forming is in front of them. [12]

Hi-Fi — Ability of some VCRs to record high fidelity or true-to-life sound. VHS and 8mm hi-fi VCRs record stereo sound with almost “perfect” sound quality. [5]

Hi-fi audio track — High quality sound recorded physically beneath the video vibrations as they are magnetized into diagonal tracks on the tape. [10]

High Band — High-resolution (over 400 lines) VCR format. [5]

High level or hi level — Strong audio signal typically sent from an aux out or a line out of a device. [5]

High Speed duplicator — Device able to duplicate a tape in under a minute. [13]

High speed shutter — An electronic circuit in a video camera that allows the CCD chip to “see” for a very brief amount of time during each 1/60 second. Like in a film camera, the fast shutter speed reduces motion blur. [6]

High-gain screen — Rigid, curved, foil-covered projection screen with a gain of 5 or more which yields a bright projection image, even in a well-lit room. [19]

High-pass filter — An antenna filter which allows normal TV channel frequencies to go to the TV set but stops INTERFERENCE from lower frequencies. [3]

HMI light — Halogen metal iodide lighting instrument. Very efficient and uses minimal power, but requires a heavy ballast. Gives off light with 5500°K color temperature. [9]

Horizontal linearity — TV adjustment which controls how a TV reproduces shapes without stretching or distorting them in the horizontal direction.[2]

Horizontal phase or H phase — Control on a camera’s timing circuits which adjusts the picture sideways to line up with other cameras’ pictures. [6]

Horizontal size or width control — TV set control which makes the picture skinny or fat. [2]

Horizontal sync — The part of a sync signal which aims the TV’s electron gun left and right. This holds the picture from jittering or straying sideways. [1]

Host adapter — Computer circuit that controls the hard drive and processes data going onto or from the drive. [5]

Hot switching — Inserting a new battery and then removing a failing battery while a device continues to run. [16]

House lights — General overhead work lights used in the studio during rehearsals and between productions. [9]

Hue — Identity or name of a color. Blue is a hue. [12]

Hum bar — Hum is usually 60-Hz (60 cycles per second) electrical interference from power lines. When seen on a TV screen, this interference creates a soft dark bar across the screen. [2]

Hybrid Fiber/Coax or HFC — Cable TV or phone system infrastructure that uses optical fiber for the high traffic trunk lines and cheaper coax wire between nodes and the homes/businesses.

Hyperband — Cable TV channels 37-62. [4]

Hypercardioid microphone — Very unidirectional and slightly cardioid microphone. [10]

I encoder — Electronic circuit in a camera that mixes colors into a single color video signal. Responsible for certain colors. [15]

Illumination model or materials model — Way of describing the computational complexity of a graphic. Solid colors are simple, reflections and refractions are complex and slow your renders. [12]

Image capture board — Circuit in a computer that digitizes video signals, converting them into data the computer can store, manipulate, or display on its screen. [2]

Image enhancer — Electronic device that crispens a TV picture (making it look sharper although it isn’t really) by exaggerating the boundaries of parts of the image. [15]

Image intensifier — Electronic device that brightens the image fed to a TV camera—used in military and surveillance. [9]

Image — Part of a 3-D graphics package that renders the final image. [12]

Impedance matching transformer — A small adapter which allows a cable with one impedance to connect to an input, output. or cable of another impedance. For TV antenna signals these transform 75 to 300 and vice versa. Also called a balun.[3]

Impedance — Measured in ohms (), it is an electrical property of a circuit involving its resistance to electrical current. Devices and cables of the same impedance can work together. Those of differing impedances have difficulty. [3]

Import — Copy the data from another computer file into the file you’re working on, effectively adding a picture to your picture. [12]

In-camera editing — Recording scenes chronologically, one after another in the camcorder with the intention that all the shots will be used; a final tape emerges from the camcorder. [14]

Index counter — A mechanical indicator on older VCRs like the mileage meter on a car which changes numbers as the tape moves through the machine. It is handy for locating events on a tape or estimating the length of a production. [5]

Index search, index record — System for recording a trigger pulse invisibly on the tape so that when the tape is played in fast forward or rewind, it will stop when it reaches the marked spot. [5]

Index — Subdivision of a song or track on a CD allowing you to play a particular stanza or phrase. [10]

Infrared — Light so red that it’s invisible to human eyes. When used in autofocus cameras, it reflects off a subject to sense the distance to the subject in order to focus the lens. [6]

Infrared receiver — Device to convert an infrared light beam into electrical signals. [15]

Infrared transmitter — Electronic device to convert electronic signals, such as audio and video, to infrared (invisible to the eye) light beams. Beams travel through air and can be converted back to electrical signals by an infrared receiver. [15]

In-line amplifier — An amplifier inserted between two wires to boost the signal through them, getting its operating power through the same wires from a distant power supply. [15]

Input selector — Switch determining which input (which source) a VCR will “listen” to. [5]

Insert edit — Feature allowing A VTR to record a new segment in the middle of a program, erasing what it’s replacing. [5]

Insert edit — The recording of a new video segment amidst old, prerecorded video-unlike assemble edit, which places each new segment at the tail of the last segment. [14]

Insertion loss — A decrease in signal strength when a device is connected into a circuit. Accessories with low insertion losses are desirable to preserve signal strength. [3]

Instant video confidence — Feature on some VTRs which allows them to play back the picture hundredths of a second after it is recorded while the VTR is still recording it. Handy for assuring the video heads are not clogged. [5]

Intelsat — International satellite, one serving several countries. [20]

Interactive cable — Cable TV that not only sends shows and/or computer data to your home but receives signals from you such as a fire/burglar alarm, orders to purchase goods, and computer signals (i.e. Internet).[4]

Interactivity — The ability of a machine to react to the responses of its user. An interactive videodisc system may ask the viewer a question, wait for a response, and then display a certain sequence keyed to that response. [18]

Intercom — An earphone/microphone headset that allows the director in the control room to speak with the camera operators in the TV studio. [6]

Intercutting — Editing together several separate events or interviews to tell one story, make one statement, or answer one question using pieces from each. [17]

Interference — Unwanted signals which “leak into” your wires or devices and compete with your desired picture and sound, often causing grain, snow, or diagonal or wavy lines on a TV picture. [3]

Interframe compression — Digital reduction which compresses data within a series of frames as well as in each frame. MPEG is an example. [12]

Interlace scan — Method of making a TV picture by drawing the odd numbered lines on the screen with one sweep, then filling in between with the next sweep of even numbered lines. The process is repeated approximately every 1/30 second. [2]

Internally locked — A VCR that plays a tape independently, with its sync timed to its own internal clock. [14]

Internet service provider or ISP — Company that connects to the Internet through their fast phone lines, and provides you access to the Internet, perhaps via phone link, between your computer and theirs. They may also provide other services such as e-mail and worldwideweb (WWW) pages. [20]

Interpolator or universal format converter — A device to change one kind of DTV format into another. [21]

Interrupted feedback — Intercom system that feeds the program’s sound (music and voices) to the talent’s ear, but can be interrupted with a private announcement directly from the control room perhaps a command from the director. [10]

Intraframe compression — Data-reducing compression within a single picture or within each picture individually in a series. Example: JPEG and MJPEG. [12]

Inverse kinemation — 3-D animation feature that calculates how connected objects, such as parts of a body, will bend at the joints and follow as the farthest part is moved. [12]

Inverter — A device which changes DC electricity (from a battery) into AC electricity (from your wall outlet). [6]

IRD — Integrated Receiver Descrambler, a satellite receiver with a descrambler built in. [20]

IRE — Institute of Radio Engineers, is a measure of video level or “whiteness” and is marked off in units of 10 on waveform monitors. A 20 IRE level represents a dark part of a TV picture and 80 IRE, a light part. [15]

IRT — Integrated Receiver Transcoder, another name for an IRD, often a digital model. [20]

ISDN — Integrated Services Digital Network, a souped-up telephone line that handles digital signals. [20]

ITFS — Instructional Television Fixed Service-a method of broadcasting TV programs throughout school systems via low-power high-frequency transmitters. [15]

ITU — International Telecommunications Union, a standards-setting body for videoconferencing. [20]

Jog — To move a video tape forward or back a very short distance (one or two frames) in search for the “perfect” place to edit. [14]

Joystick — A multiposition lever on a studio switcher that positions special effects anywhere on the TV screen. [11]

Jump cut — An edit from one scene to a very similar scene, causing the picture to “jump” from one position to another. Such edits should be hidden by video inserts of related scenes (cutaways). [14]

Juxtaposition — Editing together opposites, like opposing views or conflicting responses to a question. [17]

Key (or luminance key) — Special effect where the dark parts of one camera’s picture are replaced with parts from another camera’s picture. [11]

Key light — Brightest and main source of lighting for a subject, creating the primary shadows. [9]

Key sensitivity — Control on a switcher/SEG that determines how dark something has to be before it disappears and is replaced by another camera’s picture. In chroma keys, it determines how much color something needs before it is replaced by another camera’s picture. [11]

Keystone — A distorted view of an object (usually a graphic) caused by aiming a camera at it from an angle; the nearer part of the graphic appears larger than the farther part. A square could take on a trapezoidal “keystone” shape. [12]

Keystoning — Projection phenomenon where a projector is aimed at an angle to a screen forming a trapezoidal image. [19]

Kilohertz — One thousand cycles (vibrations) per second, represented by 1 KHz, which is near the sound frequencies of speech. [4]

Kinemation — 3-D animation feature allowing you to move one part of a flexible, jointed object, and have the other parts follow naturally. [12]

Kiss black — Fade to black followed immediately by a fade up on a new picture. [11]

Ku-band — A range of microwave frequencies between 12.5 and 18GHz. [20]

Kukaloris or cookie — A metal pattern which, when inserted in a pattern spotlight, projects a design. [9]

LANC — Local Application Network Control, a Sony-developed system for controlling VCRs (mostly 8mm Hi8 camcorders) over a two-way communications link. [14]

Lasso — Adobe paint tool for selecting parts of a picture. [12]

Layer — Part of a computer image, separate from the other parts, which can be changed independently from them, like changing the background behind a cartoon figure. [12]

LCD panel or computer display panel — LCD device which when placed on an overhead projector can project computer data. [19]

LCD projector — Projector (with built in light source as opposed to the LCD panel that used an overhead projector for light) using a liquid crystal mosaic to create the image. [19]

LCD viewfinder — Liquid Crystal Display, a color TV monitor made of a flat panel rather than a CRT. Usually folds out from a camcorder or is imbedded in it. [6]

Lead-acid or Gel-cell — Battery designed like a miniature car battery, only with gelatin inside rather than liquid. Less expensive than NiCd; used in camcorders. [5]

Leader — Unrecorded space (from 10 seconds to 3 minutes) at the beginning of a tape, often used to protect the actual program from threading damage. Also unrecordable plastic tape attached to the beginnings of cassette rolls. [5]

Leaf shutter — A flap inside a photographic camera that moves aside for a moment to let light enter and then snaps closed. [13]

LED — Light emitting diode, a tiny lamp that can blink very quickly, uses little power, and lasts a long time. Often used as an indicator on equipment. [10]

Legal colors — Colors that reproduce correctly in NTSC video. Some computer generated colors are called “illegal” in that they are out of the range of what common TVs can display. [12]

Legal video — Video production, editing, and display as it relates to the law and the courtroom. [17]

Lens format — Describes the size of the lens’s focused image. It should match the size of the camera’s pickup chip. [7]

Lens shade — A funnel-shaped visor that attaches to the outside of a lens shading it from lights and the sun. [7]

Lenticular — Gray, metallic-looking projection screen with tiny vertical grooves (looks like smooth corduroy) to distribute most reflected light straight back and to the sides (where the audience sits) and reflects very little on the ceiling and floor. [19]

Level 1 videodisc player — Often a consumer model player with features such as freeze frame, picture stop, chapter stop, scan, and two-channel audio but without the computer memory or the ability to select on its own which sequences to show. [18]

Level 1/2/3 videodisc player — A combination level 1, level 2, level 3 videodisc player. [18]

Level 2 videodisc player — An educational/industrial videodisc player, usually with all the level 1 capabilities plus a small computer built in. Computer programs (instructions) coded in the audio track of the disc are loaded into this computer when you start the disc playing, telling the player which sequences to play as a result of viewer responses. [18]

Level 3 videodisc player — Videodisc player linked to an external computer. The computer program, perhaps from a floppy diskette, controls the sequences the videodisc player will play. The computer may also display graphics and questions of its own. The disc serves mostly as a storehouse of still and moving pictures and sound. [18]

Level 4 videodisc player — Videodisc player with computer, able to read a large computer program from the disc, and thereafter runs like a level 3 player. [18]

Light meter — Electronic device that measures the brightness of a light (incident light) or the brightness of a scene (reflected light) and gives a readout in footcandles or lux. [9]

Light pen — Pen-shaped device connected to a computer that the viewer points or touches to a TV screen in response to computer questions rather than typing the answers on the computer’s keyboard. [18]

Light valve projector — Expensive, professional projector that creates bright images by bouncing light off a reflective surface inside. The reflective surface changes its reflectivity based on video or computer images presented to it. [19]

Lighting grid — Framework of pipes connected to the studio ceiling from which lights are hung. [9]

Lighting plot — A drawing to show where the lights are to be aimed. May also include fixture numbers and circuit numbers and show prop and performer positions. [9]

Lighting ratio — A comparison between the brightest part of a subject and the darkest. If the brightest white in a performer’s shirt measured 60 fc (footcandles) and his black hair measured 2 fc, then the lighting ratio would be 60 2 = 30. [9]

Lightning arrester — Device which clips onto an antenna or cable TV cables, and connects to a grounded wire. It is designed to divert the shock of a lightning bolt so that the current doesn’t damage your equipment.[3]

Limiter — Electronic audio device that automatically reduces the volume of loud audio signals but doesn’t change the normal or weak signals. [10]

Line — An external auxiliary input often used for a video signal. Can also be the final video or audio output signal from a device. [2]

Line doubler — Device that doubles the scan lines that makes a picture, essentially placing lines between lines, improving the look of video when shown on computer-like devices such as computer projectors. [19]

Line or program monitor — TV monitor that shows the final signal being broadcast or sent to the VTRs. [11]

Line quadrupler — Device that quadruples the scan lines in a picture, making video look better when shown on high resolution computer projectors. [19]

Linear (or normal) audio track — Audio recording made in a line along the edge of a video tape (as opposed to hi fi sound imbedded in the video tracks on the tape). [5]

Linear audio track — A stripe of magnetic vibrations along the edge of a video tape that contains the audio signal, laid down by a stationary record/play head. [10]

Linear key — Key effect where the amount of a color (or brightness) determines how much of another camera’s image will be visible, creating a natural-looking key effect. [11]

Linear screw rod — Inexpensive satellite aiming actuator moved by a long threaded bar. [20]

Lip Sync — Synchronization between the performers’ audible words and the movement of their lips. [14]

Liquid crystal light valve (LCLV) projector — Expensive, professional projector that uses amorphous (not dots of) LCD material to sense a dim CRT image and make a surface reflective. Light from a bright projection lamp reflects off the surface to make the projected image. [19]

Lithium ion — Ultra small battery for camcorders. [5]

LNA — Low Noise Amplifier used to boost the dish antenna’s signal. Satellite signals are so weak they have to be amplified (multiplied) 100,000 times. Special circuits with premium grade transistors are needed to allow the signal to be amplified so much without adding appreciable visual “noise” to the signal. [20]

LNB or LNC — Low Noise Blockconverter or Low Noise Converter, an LNA with a circuit built-in that lowers the microwave frequencies, making them pass easily through common coax wire to your satellite receiver. [20]

Lo Z — In audio, any input of 500 ohms impedance or less. [10]

Logo — Symbol or trademark representing a specific company, or organization, or TV station. [12]

Loop antenna — Circular portable UHF antenna.[2]

Loop or bridge — An electrical connection which allows most of the signal to enter one socket and continue out an adjacent socket to be used elsewhere. [2]

Loop through — The act of sending a signal to and through a device (using a bridged input) and then on to another device. [2]

Lossy — Compression method that discards data and degrades the image quality. High degrees of compression are possible. [12]

Lossy — Compression method that discards some data, to some degree damaging the signal it represents. [5]

Low contrast filter — Lens filter that reduces contrast by making shadows lighter. [7]

Low cut filter — An audio circuit, often built into mixers and mikes, that reduces low tones from a sound signal. [10]

Low level or microphone level — Weak audio signal, as from a microphone. [5]

Low light level camera — TV camera designed to “see” with very little light—used in military and surveillance. [9]

Low-pass filter — Filter placed between a radio transmitter and its antenna to reduce the harmonics from being broadcast. The harmonics interfere with people’s TV reception.[3]

LP — Long play—The 4-hour speed of a VHS VCR. [5]

LPTV — Low-Power Television-the technique of broadcasting local programming through a very low-power, inexpensive VHF TV transmitter. Limited signal range keeps LPTV stations from interfering with distant TV stations using the same channel frequency. [15]

LTC or Linear Time Code — Time code recorded in a linear stripe along the tape, perhaps on a longitudinal audio track. [14]

Lumen — A measurement of a source’s light brightness. Lumens per square foot equals foot-candles. [19]

Luminance — The black-and-white (brightness only) part of a video signal. [1]

Lux — A measure of illumination, the amount of light needed to make a 1-volt video signal. [6]

Lux — A measure of the brightness of an object in a scene. Cameras need a certain degree of scene brightness in order to register a picture. 10 lux equals about 1 footcandle, another measure of brightness. [9]

LV — Laservision. A videodisc read by a laser, the light of which reflects off microscopic pits in the disc. Not the same as CED videodiscs. which use a groove. [18]