Audio/Video Glossary

MII: Portable, professional video component camera/recorder format, utilizing 1/2" metal particle videotape. JVC’s answer to Sony’s Betacam format.
MADI: (AES10) multichannel digital audio interface that supports 56 channels.
MASTERING: Technically, refers to the process of creating a glass master from which compact discs will be reproduced in quantity. In professional circles, the term is loosely used to refer to the process of preparing audio and video information for the pre-mastering phase.
MATRIX SWITCHER: A device which uses an array of electronic switches to route a number of audio/video signals to one or more outputs in almost any combination. Production quality matrix switchers perform vertical interval switching for interference free switching. Matrix switchers may be operated with RS-232 or RS-422 controls, enhancing flexibility.
MB (Megabyte): 1,048,576 bytes of data or 1024 Kilobytes. This should not be confused with a Megabyte of disk space which is computed by multiplying 1000 x 1000.
MEDIA CONVERSION: The process of converting data from one type of media to another for premastering and mastering. Premastering software typically requires input data on hard disk. 8mm tape and compact disc are preferred as input media for the mastering process.
METALIZING: A process in which a thin layer of aluminum is deposited on a clear plastic disc after it has been injection molded. The usual deposition method is by sputtering, although vacuum vapor deposition or wet silvering can also be used.
MICROPHONE PREAMPLIFIER: A microphone is a device which converts sound waves to electrical impulses (transducer). Microphones typically generate very low signal levels requiring low noise, high fidelity, pre-amplification to boost the output signal to a level compatible with audio amplifier circuitry. Good microphone preamplifiers provide precise matching of microphone impedance and low noise electronic components.
MICROPHONE IMPEDANCE: In order to obtain the highest quality output signal from a microphone, a preamplifier input should provide a load (impedance) which exactly matches a microphone’s output impedance. Microphone output impedances vary from 150 ohms to several megohms.
MIDI (Musical Instrument Digital Interface): A universal electronic computer-generated data language used to compose/record musical performances and sound effects using various keyboards, synthesizers and other electronic equipment.
MIXED-MODE: A compact disc including both computer data and CD-DA tracks. The data is all contained in Track #1 and the audio in one or more following tracks (#2-99).
MIXING: The blending of two or more audio or video signals to generate a combined signal.
MO (Magneto Optical): (See CD-MO)
MODE: There are two recording modes for compact discs; Mode 1 and Mode 2.
MODE 1: Most common CD-ROM data format. In Mode 1, 288 bytes of each sector are used for storing three layers of error correction code, leaving the remaining 2048 bytes per sector for user data.
MODE 2: Data format utilized in CD-I and CD-ROM XA. Mode 2 has two forms. Form 1 is similar to Mode 1, but storing only two layers of error correction code. Form 2 is used for recording information such as audio or compressed video which do not require such extreme precision. Since less error correction is needed, more bytes in the sector can be freed for information storage, resulting in a data area of 2336 bytes per sector.
MOIRÉ: A distracting wavy effect produced when converging lines in a video image are nearly parallel to a monitor’s scanning lines.
MONITOR: A display that gets its signal directly from a camera or VCR, as opposed to a television, which relies on RF signals, such as those from cable television or broadcast. A monitor uses composite (RCA-style), S-video (Y/C) and/or BNC video jacks. (See ANALOG MONITOR)
MOSAIC: Special effect in which the picture is divided up into tiles.
MOTHER: In disc replication, the name typically given to the metal master created from the nickel coating which is deposited and then separated from the “father” metal master. The mother is a positive image, identical to the glass master. Multiple stampers are then made from the mother.
MOUNT: To install a CD or DVD disc so that the computer recognizes its presence and can read data from it.
MP3 (Moving Picture Experts Group 1, Layer 3): Abbreviated term given to a method of compressing audio files. MP3 compression is accomplished by relying on a natural phenomenon called psychoacoustic masking to reduce the amount of data by as much as a factor of 10, inevitably degrading the sound quality somewhat. On a CD, each minute of stereo audio takes up about 10MB (MegaBytes) of space. Very few people would want to download a 40MB file just to hear four minutes of music. With MP3 compression, the same four minute song takes up about 4MB. This is a much more practical size for sending over the Internet.
MPEG (Motion Picture Experts Group): The name applied to the digital compression standard for moving video images allowing them to occupy less memory or disk space. Like the JPEG standard it includes options for tradeoffs between storage space and image quality.
MULTI-STANDARD: A monitor which synchronizes to different video signal standards such as NTSC and PAL. (See ANALOG MONITOR)
MULTIMEDIA: A somewhat ambiguous term that describes the ability to combine audio, video and other information with graphics, control, storage and other features of computer-based systems. Applications include presentation, editing, interactive learning, games and conferencing. Current multimedia systems also use mass storage computer devices such as CD-ROM.
MULTIREAD: An OSTA standard for CD-ROM and DVD-ROM drives. Drives which follow the MultiRead standard can read commercial CDs (audio and data), CD-R and CD-RW discs. They can also read discs written in fixed or variable-length packets.
MULTISCAN MONITOR: A monitor (also referred to as multi-sync or multi-frequency) which synchronizes to different video signal sync frequencies, allowing its use with various computer video outputs. (See ANALOG MONITOR)
MULTISESSION: Specification which allows additional data to be appended to previously recorded disc sessions. All of the data in the various sessions, look as if it had been recorded in one single large session. If the data between sessions is linked (also referred to as a linked session), all data on a multisession disc may be seen as part of a single logical structure when read on a compatible CD-ROM drive. The multisession specification is part of the Orange Book standard.

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