Grass Valley PROFILE FAMILY v.2.5 - Manual (Page 371)

Glossary
Profile Family 371
speed playback. In the range of 12 to 15 fps, the human eye can detect the
difference between one frame and the next; visually this appears as a jerky
motion, or flicker.
Frame
The standard unit of measure for film and video. One frame represents one
complete still image, divided into two fields.
Frequency response
The frequency range which an electronic component can accurately
reproduce. Humans (some) can hear from 20 Hz to 20,000 Hz (20 KHz). An
ideal audio component would have a frequency response, totally flat and
without any deviation, from 20 Hz to 20 KHz. Frequency response
specifications are measured in decibels (dB), based on how closely an
output’s response resembles that of the input.
Genlock
This term defines the relationship between video paths. Two video signals
that are exactly synchronized are said to be genlocked.
GUI
A Graphical User Interface (GUI) provides a visual way to interact with
computer software. GUIs allow people to control an application by using a
pointing device such as a mouse to perform operations. The usual alternative
to a GUI is a command-line interface, which requires people to type in
application-specific commands following precise rules of syntax. GUIs are
considered easier to use than command-line interfaces.
Group
In audio terms, this provides the ability to group tracks to perform functions
across several tracks at the same time, such as gain, mute, etc.
GOP
A Group of Pictures (GOP) is part of the video compression scheme used by
MPEG. MPEG uses motion prediction to increase efficiency, that is, it
reduces data by not duplicating pixels that do not change from frame to
frame. It does so by relying on a GOP. A GOP is composed of I-frames, B
pictures, and P pictures. See B Picture, I-frame, P Picture.