Audio/Video Glossary

1,073,741,824 bytes of data or 1024 Megabytes. This should not be confused with a Gigabyte of disk space which is computed by multiplying 1000 x 1000 x 1000.

GENERATION

The number of duplication steps between an original recording and a given copy. A second generation duplicate is a copy of the original master and a third generation duplicate is a copy of a copy of the original master, etc.

GENERATION LOSS

When an analog program material is duplicated, the second-generation copy is usually inferior in some way to the master.

In audio, this degradation most often appears as added noise, higher distortion and altered frequency response.
In video, this degradation appears as loss of detail, improper colors, sync loss, etc.

Limited frequency response of audio/video magnetic tape and imperfections in electronic circuitry are the main causes of generation loss. Higher performance formats (such as 1-inch) exhibit much less generation loss than more basic formats. Digital formats make generation loss negligible because each copy is essentially an exact duplicate of the original.

GENLOCK

A method of synchronization involving the generation of a video signal sync-locked with another signal. Because they are synchronized, a genlocked signal can be mixed with the original signal, allowing dissolves, wipes and other transition effects.

Genlock and frame synchronization differ in that genlock is the generation of a new signal synchronized to an existing video signal while frame synchronization takes two existing video signals and synchronizes them. Genlocking two VCRs requires the use of a time base corrector (TBC).

GHOSTING

A weak, secondary, ghost-like duplicate video image within another video image caused by the undesired mixing of the primary signal and a delayed version of the same signal.

GLASS MASTER

The disc on which the source data (from either PCM-1630 tape, Exabyte tape or CD-R) is imprinted as the first step in CD replication (mastering). The glass master is a glass plate, about 10” in diameter, coated with a light-sensitive material (photoresist). During mastering, the source signals are converted to the EFM coding format for the CD and fed to the special laser beam recorder (LBR) which etches very tiny pits on the material. The glass master is very delicate, and cannot be played. Succeeding steps in the process, called the “father”, “mother” and stamper, result in the metal forms which are capable of hot molding thousands of compact discs on the presses.

GREEN BOOK

(See CD-I)

GROUP DELAY

A phenomenon involving timing differences between video signal components. For example, a long cable run may introduce a substantial delay between the transmission of the color and brightness video information resulting in shadows.

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