Glossary -I-
I encoder — Electronic circuit in a camera that mixes colors into a single color video signal. Responsible for certain colors.
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.
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.
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.
Image intensifier — Electronic device that brightens the image fed to a TV camera—used in military and surveillance.
Image — Part of a 3-D graphics package that renders the final image.
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.
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.
Import — Copy the data from another computer file into the file you’re working on, effectively adding a picture to your picture.
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.
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.
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.
Index — Subdivision of a song or track on a CD allowing you to play a particular stanza or phrase.
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.
Infrared receiver — Device to convert an infrared light beam into electrical signals.
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.
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.
Input selector — Switch determining which input (which source) a VCR will “listen” to.
Insert edit — Feature allowing A VTR to record a new segment in the middle of a program, erasing what it’s replacing.
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.
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.
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.
Intelsat — International satellite, one serving several countries.
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).
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.
Intercom — An earphone/microphone headset that allows the director in the control room to speak with the camera operators in the TV studio.
Intercutting — Editing together several separate events or interviews to tell one story, make one statement, or answer one question using pieces from each.
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.
Interframe compression — Digital reduction which compresses data within a series of frames as well as in each frame. MPEG is an example.
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.
Internally locked — A VCR that plays a tape independently, with its sync timed to its own internal clock.
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.
Interpolator or universal format converter — A device to change one kind of DTV format into another.
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.
Intraframe compression — Data-reducing compression within a single picture or within each picture individually in a series. Example: JPEG and MJPEG.
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.
Inverter — A device which changes DC electricity (from a battery) into AC electricity (from your wall outlet).
IRD — Integrated Receiver Descrambler, a satellite receiver with a descrambler built in.
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.
IRT — Integrated Receiver Transcoder, another name for an IRD, often a digital model.
ISDN — Integrated Services Digital Network, a souped-up telephone line that handles digital signals.
ITFS — Instructional Television Fixed Service-a method of broadcasting TV programs throughout school systems via low-power high-frequency transmitters.
ITU — International Telecommunications Union, a standards-setting body for videoconferencing.
