Matrox DigiSuite LE, Installation Manual, Page: 125 / 140

113
Glossary of terms
key source
The image that contains the colors
or luminance values on which you key to create a
chroma or luminance key effect.
L
lossless compression
See mathematically
lossless compression.
lossless video
See uncompressed-quality
video.
lossy compression
A method of compressing
video that results in loss of image information, and
thus degrades the image quality. The loss of image
quality, however, may not be visible. On
DigiSuite, lossy compression performed using a
high data rate creates video that’s virtually
lossless. Contrast with mathematically lossless
compression.
LTC
Longitudinal Time Code. Time code that is
generally encoded as an audio signal onto a linear
audio track of a tape. This type of time code can be
read only while the tape is moving. See also
VITC.
luminance
The brightness portion of a video
signal. The luminance of a pixel determines its
brightness on a scale from black to white. See also
chrominance.
luminance key
An effect that makes portions
of a foreground image fully or partially transparent
based on the luminance of that image (or another
source), so that an underlying image can show
through. See also key source, self-key, and filled
key.
M
mark in
To select the first frame of a clip.
mark out
To select the last frame of a clip.
mathematically lossless compression
A
method of compressing video without losing
image quality. The video is identical to
uncompressed video, but requires less disk space.
Contrast with lossy compression. See also
uncompressed-quality video.
M-JPEG
See Motion-JPEG.
module board
Printed circuit board and
mounted components that is attached to the base
board using screws and spacers.
mosaic
An effect that “blurs” an image by
copying pixels into adjacent pixels both
horizontally and vertically. This gives the image a
blocky appearance, often used to hide people’s
identities on television.
Motion-JPEG
A compression and storage
standard used for motion video. The JPEG
compression process is applied to each video field,
in succession. Also called M-JPEG.
Movie-2 bus
or
Movie-2 bus
connector
Over-the-top connector used for
high-speed data transfer. These two terms refer to
the assembled component, which consists of a
printed circuit board (backplane) with attached
connectors.
MP@ML
Main Profile@Main Level. An
MPEG-2 video compression profile that supports
4:2:0 luminance/chrominance sampling at up to
720×576 pixel resolution, and data transfer rates
up to 15 Mb/sec (2 MB/sec). This profile is used
for broadcast transmission and distribution on
DVD. See also 4:2:2P@ML.
MPEG
A video compression standard that
specifies a series of compression profiles and
image resolution levels, introduced in 1990 by the
Motion Picture Experts Group. MPEG takes
advantage of the redundancy inherent in video data
through a combination of inter-frame and intra-
frame redundancy reduction. The MPEG standard
supports data transfer rates of up to 1.5 Mb/sec
(0.2 MB/sec). Also called MPEG-1. See also
MPEG-2, inter-frame (IBP) compression, and
intra-frame (I-frame) compression.