Technical Glossary
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Displaying 65 glossary terms found.


Abbreviation for one thousandths. Example: 1 ms = 1/1000 second.

M - Mega
An abbreviation for one million. A megabyte is actually 1024K, or roughly a million bytes (1,048,076 to be exact [1024 x 1024]).

Process used in prerecorded videotapes and DVDs to prevent unauthorized duplication. Named for company that originated process. Places flashing boxes in vertical interval that confuse VCR circuity that regulate brightness. Can result in unwatchable picture or no picture in illegally duplicated tapes. May also interfere with normal playback even when no unauthorized duplication is attempted.

Abbreviated term for magnetic, or the full-coat magnetic film stock. See Full-Coat Magnetic.

Magnesium Carbonate
MgC03. A screen material used in matte white screens that looks like white chalk and technically may be called a "perfect white diffuser." That phrase implies that no light striking such a surface will be absorbed and that all light so impinging will be reflected in a pattern that is isotopic. Thus, the energy from any light ray arriving normal to the screen will be scattered identically in all directions.

A generic term used to denote the processes of recording, mixing, printing, and playback of film sound on magnetic media. Also used to differentiate prints with magnetically recorded sound as opposed to those with optical tracks. Magnetic soundtracks on film existed mainly in the 1950s and were discontinued soon after; although they were superior to optical, the cost of magnetic sound recording/playback was considered too expensive by the studios. They are still prominent on 70mm features shown today.

Magnetic Deflection
A method of altering the path of an object (such as an electronic beam) with a magnetic field. CRTs have magnetic coils that carry currents which create magnetic fields that control the path of electron beam. Also called magnetic focus.

Magnetic Field
The area surrounding a magnet, which is affected by it. The field created by magnets in telephones, electric motors, TVs and other consumer electronic products is usually felt for a foot or two around them.

Magnetic Focus
See Magnetic Deflection.

Magnetic Soundtrack
Narrow stripes of oxide material (similar to the coating on magnetic recording tape) that are added to a developed theatrical release print, then recorded in real time with the film's sound. For playback in the theatre, projectors are equipped with magnetic playback heads like those on a tape recorder. Introduced in the l150s to provide stereo sound in the cinema, magnetic offers very high sound quality. The prints themselves and theatre maintenance are costly, however, so today there is only one magnetic format that remains-six-track 70mm. Magnetic coating also is applied to full coat 35mm film for use as the (audio only) soundtrack printmaster (typically Dolby(r) SR encoded). This magnetic printmaster is the source master for all theatrical prints, both matrix encoded and discrete digital release prints in Dolby Digital, DTS(r) Digital Sound, and SDDS(r).

The process by which one sound is used to obscure the presence of another, The theoretical basis of perceptual coding.

Mass Law
The law of physics which states that a material's ability to reduce the transmission of sound is proportional to its weight. According to the mass law, to decrease a wall's transmission by 6 dB it is necessary to double the thickness of the wall. See Inverse Square Law.

1) The electronic process of encoding and decoding multichannel sound in the analog or digital domain. In a matrix encoder, four channels are combined into two. Decoding is accomplished through extraction of the four channels from the encoded tracks. The most widely used theatrical matrix encode/decode systems are that from Dolby Laboratories and Ultra Stereo. Also used to describe a similar type of circuit that can synthesize a rear channel(s) for ambiance even if the original recording consists of only left and right stereo channels. 2) In video combining signals in specific proportions. Source matrix forms Y, I, and Q video signals in the output for R, G, and B input. At the receiver, the three-gun picture tube is often the matrix for input of R-Y, B-Y, G-Y and Y signals to produce red, green, and blue light from the screen. 3) In A/V, an electronic device used to collect and distribute video (and sometimes audio) signals. See Matrix Switcher.

Matrix Switcher
In audio/video, a means of selecting an input source and connecting it to one or more outputs. Like a switcher, but with multiple inputs and multiple outputs.

Matte White
A screen with a flat, dull surface for even reflection over wide viewing angles.

Matte White Screen
A screen material typically made of magnesium carbonate that by definition is a unity gain surface. It does not have a gain greater than 1.

In letterbox presentations the blanking of picture area at the top and bottom of a full frame of film. Though the upper and lower parts of the film frame are not intended to be seen on films produced in spherical flat 1.85:1 and Super 35, this numerous films are released to home video in which the full frame is not matted to avoid black bars at the top and bottom of the screen. A "hard matte" may be applied to the camera during filming to create a widescreen image. A "soft matte" is a post-production process that is done digitally when a film is transferred to video disc or by means of projection gates in a movie theatre. See Pan-And-Scan.

(As in 20 MB) An abbreviation for megabyte. A megabyte is 1024K, or roughly a million bytes (1,048,076 to be exact [1024 x 1024])

Megabits per second. A data transmission rate.

Monochrome Display Adapter. Resolution 720 x 350. A graphics card found in the IBM PC and PC XT - AT series.

Mechanical Coupling
To rigidly connect two isolated objects. Also referred to as a mechanical short. Example: Two isolated wall partitions are mechanically coupled if rigid electrical conduit is fastened to both walls. Air ducts and plumbing are prime candidates for causing mechanical shorts. When an acoustically isolated room "leaks," it is often a mechanical short created during construction.

Mechanically Decoupled
The elimination of mechanical shorts. See Mechanical Coupling. Typically accomplished by inserting a flexible loop between rigid components. Flexible metallic conduit (greenfield) is used for decoupling electrical conduit, accordion shaped canvas collars decouple rigid air-ducts and flexible tubing does the same for plumbing. For structural decoupling non-compressible foams like Ethafoam 222 or AP Armaflex separate rigid components. Megahertz - Mhz. One million hertz (cycles).

Circuitry and devices that hold information, in electrical or magnetic form, such as a preset or programmed set of destinations on a LaserDisc, CD player or a pre-set TV station frequency in a frequency-synthesized receiver.

Meridian Lossless Packging
See MLP.

Multi-Frequency Termination Adapter. A single termination device with selectable frequencies for different applications.

Megahertz. One million hertz (cycles). An abbreviation for megahertz. This is a unit of measurement and refers to a million cycles per second. Video bandwidth is measured in megahertz.

Abbreviation: Bar. The basic measuring unit for atmospheric pressure and therefore sound pressure. Microbar is a measure of force per unit area (i.e. 1 microbar = 1 dyne/cm2). Since sound consists of a rapid fluctuation in air pressure, the measurement of a "sound pressure" actually refers to its RMS value. At 1 kHz the approximate threshold of hearing is 2 X 10-4 microbar (i.e. .0002 bar). This value is used as a reference level by which all other sounds are measured. See Decibel.

A small, self-contained computer. Also called desktop, personal or portable computer.

A sheet of microfilm, usually 4x6-inch, containing multiple images in a grid pattern. Microfiche is designed for use in a special reader, but normally contains a title strip which can be read without magnification.

A film in which each frame is a miniaturized image of a printed page or photograph. May be sized at 16mm, 35mm, 70mm or 105mm.

One millionth of a volt (uV).

The frequencies spanning the upper range of bass to the lower region of midrange (approximately 80-250 Hz).

The region of audio frequencies between bass and treble. Much of film dialogue is centered in this region. The range is approximately 150 Hz to several kHz.

Million Instructions Per Second - The rate at which a computer executes instructions.

Device for reflecting light. May be a flat plane or curved. Used in projectors behind lamps to concentrate and distribute light, to reverse images for correct viewing, and to fold light beams for more compact systems. Mirrors for A/V applications have a reflective coating on the front, or first surface, to prevent double images (ghosting).

1) The blend of dialogue, music, and effects which comprises a film's soundtrack. 2) When used as a verb, the process of assembling and balancing these elements electronically, thereby creating a final soundtrack master.

Meridian Lossless Packing. This is a data compression technique designed specifically for high quailty (96kHz/24-bit) sonic data. MLP differs from other data compression techniques in that no significant data is thrown away, thereby claiming the “lossless” moniker. MLP is also a standard for the 96kHz/24-bit portion of the DVD-Audio disc (1999). Dolby Laboratories has exclusive rights to license MLP to electronics manufacturers.

A room resonance. Axial modes are associated with pairs of parallel walls. Tangential modes involve four room surfaces and oblique modes all six surfaces. Their effect is greatest at low frequencies and in small rooms.

Acronym for MOdulator-DEModulator. A device that puts information on a carrier signal and transmits it over a (phone) network. The same device receives such signals and demodulates, or separates the information from the carrier. It converts (modulates) computer data to sound and changes (demodulates) sound into computer data. A modem connects computers with other communications devices through ordinary phone lines.

Modulated Dolby(r) Digital
A form of Dolby AC-3(r) required for storing on LaserDisc. The AC-3 signal is modulated to an RF signal for storage on the LaserDisc, then demodulated on playback. On DVD, the AC-3 signal is unmodulated.

1) The process/result of changing data into information-carrying signals suitable for transmission and/or recording. 2) The process of adding an information signal to a carrier frequency to allow it to be transmitted. Thus, the carrier is "modulated" by the information signal. Example: modem.

A pattern resulting from a combination of other patterns. In video, this is usually an undesirable pattern caused by an unwanted signal interfering with the desired signal. This may appear as a pattern.

Single-channel audio delivery. See Mono.

1) A video monitor that receives a video signal directly from a VCR, camera or separate TV tuner for high quality picture reproduction. It does not include a tuner. 2) A video display designed for use with closed circuit TV equipment. 3) Device used to display computer text and graphics.

Monitor / Receiver
A video monitor equipped with RF receiving and tuning circuits, so that broadcast signals may be received and viewed.

Common Abbreviation for "monaural," meaning from a single source.

Black and white. Just luminance or brightness without color. The Y signal is a monochrome signal. In computer CRTs, any single color with a black background.

Monochrome Composite Output
Provides a monochrome video output with combined horizontal and vertical sync for Composite Video with all the shades of the computer's monochrome, 8, 16, or 64 color display adapter card output signal.

Monochrome Signal
A single color video signal - usually a black and white signal, or sometimes the luminance portion of a composite or component color signal.

A receiving or radiating device, such as a microphone or loudspeaker, whole polar pattern has uniform polarity in all directions.

In video, the term "motion" is used as opposed to "still" because there can be a difference in the way these two types of video are processed for the best viewing results, especially when the video is line-doubled or line-quadrupled. Motion video includes movies and TV programs, while still would include text and slide presentations. See Still.

Motion Mode Interpolation
MMI. Eliminates scan lines and "jaggies" in line doublers.

Moving Picture Experts Group. A standards committee under the auspices of the International Standards Organization working on algorithm standards that will allow digital compression, storage and transmission of moving image information such as motion video, (near) CD-quality audio and control data at CD-ROM bandwidth. The MPEG algorithm provides inter-frame compression of video images and can have an effective compression rate of 100:1 to 200:1.

Moving Picture Experts Group. Digital video encoding/decoding schemes in which data compression and reduction are used to increase efficiency of data space. MPEG is currently the standard for digital satellite systems (DSS); MPEG-2 is an improvement over MPEG and is used for DVD and next generation DSS. The video quality of MPEG-2 is capable of at least equaling LaserDisc.

A video compression encoding method that reduces to 1.4 Mbs the number of bits needed to represent the video signal. Provides poor picture quality.

A video compression encoding method that is a higher quality version of MPEG-1 used in DSS and DVD.

MTS Decoder
Multichannel Television Sound. TV sets in this category with a built-in TV tuner will normally include an MTS Decoder that features dbx(r) noise reduction. These are stereo sets with all of the necessary circuitry to allow television programs broadcast in stereo to be heard in stereo. An MTS Decoder receives and decodes all stereo signals broadcast by the networks, cable/satellite channels, and premium channels. Most of these stereo sets can also receive any separate or second audio program (SAP) that provides audio in a second language-normally Spanish-as long as the SAP signal is being broadcast. See TV Receiver.

A subjective term describing low frequency sound that isn't clear. See Boomy.

A term used to describe more than two channels used to record or reproduce stereo sound in a system, such as Dolby(r) Surround or the digital 5.1 channel systems. Stereo has been long associated with two channels, while home theatre is a multichannel experience.

Multipath Distortion
Distortion that occurs when broadcast signals and signal echoes (reflected off buildings or other obstructions) reach the TV receiver at slightly different times. This phenomenon creates multiple images. Also known as "ghosting."

A feature that displays up to 9 or 12 still pictures on the screen simultaneously from different channels.

Combining of two separate signals on one carrier.

Pertains to a video display that can automatically synchronize its scanning rate with a variety of input signal scan rates. A line multiplier can be used only with a multiscan display.

Multiple sub-Nyquist Sampling Encoding. A term originally used for a transmission scheme developed by NHK, the Japanese broadcast authority, specifically for DBS transmission of HDTV.

A control that reduces or eliminates audio level. or a circuit that automatically silences or reduces audio during function changes.