Tektronix Grass Valley 3000 - Manual (Page 270)

G-8
Glossary
Key Video: The video selected on a key
bus which may be the key fill, the key
source, or both.
L
Learn: The operation of storage in an
E-MEM system.
Lever Arm Transition: A transition
between primary video and/or title video
signals made by manually moving the
lever arm.
Linear Key: A key which is processed at
or near unity gain by the switcher. Clip
and gain control have very small
adjustment ranges, and keying is
performed using the luminance values of
the linear key source. A Linear Key is
normally used when the key has already
been properly shaped at the key source.
Load: To transfer data to or from a
storage device.
Looping Input, Loop-through: An
input that includes two connectors. One
connector accepts the input signal, and the
other connector is used as an output for
connecting the input signal to another
piece of equipment or to a monitor.
Luminance: The quantitative attribute
of light, measured as luminous intensity.
Corresponds to the sensation of
brightness.
Luminance Key: A key effect in which
the portions of the key source that are
greater in luminance than the clip level cut
the hole in the background scene. In
luminance keying, any video (brightness)
level above the clip level will insert the
key; any level below the clip level will turn
the key off. In the key invert mode, this
clip relationship is reversed.
M
MII Format: A color difference video
format that uses the Y, R-Y, B-Y
components.
Macro: A function that provides for one
keystroke to take the place of many
keystrokes.
Mask: A pattern used to obscure parts of
a video key.
Mask Key: A key effect in which the
keying signal is masked (gated) by an
adjustable mask window that may be
positioned anywhere on the screen. The
mask may be set to force either foreground
or background as desired.
Matrix: (1) An array of input and output
signal lines whose intersections form
crosspoints. (2) The switcher frame with
circuit boards installed is sometimes called
the matrix because the circuit boards
contain several crosspoint switching
matrices.
Matte: An internally-generated flat color
signal which is adjustable for luminance,
hue, and saturation. Mattes may be used
to fill areas of keys and borders.
Matte Key: A key effect which employs a
matte as the fill signal.