Matrox Axio Installation And User Manual page 257

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process that contains all the information
required to reproduce a complete image. It
allows random access points within a video
stream, and acts as a reference point for
B-frames and P-frames to be built. I-frames
are editable because they contain enough data
to construct an entire video frame, unlike
B-frames or P-frames.
IMX
A video recording format developed
by Sony, and standardized by SMPTE as D10,
that is used to record video and audio onto a
hard disk or tape. The IMX data format is
fully MPEG-2 compliant and supports video
data rates of 30, 40, and 50 Mb/sec. Video is
sampled at 4:2:2 for both NTSC and PAL
sources.
insert editing Recording new video
and/or audio material onto a prerecorded (or
striped) tape. Insert edits can be made in any
order, unlike assemble edits, which must be
made sequentially.
inter-frame compression A video
compression method that compares a series of
frames in a video sequence and removes the
redundant data. Inter-frame compression
treats all the frames in the sequence as an
interdependent group. As a result, most of the
frames can't be edited independently. Also
called temporal redundancy reduction.
Contrast with intra-frame compression. See
also GOP.
interlaced scanning A method of
creating a video image by drawing only the
odd numbered lines on the screen in one pass,
then the even numbered lines in the next pass.
Two passes are therefore required to create a
complete frame of video. NTSC and PAL
displays are interlaced. See also progressive
scanning.
Appendix D, Matrox Axio Glossary
interleave A technique used to incorporate
the video and audio portions of a video clip
into one file. See also AVI.
intra-frame compression A video
compression method that removes redundant
information from within a frame. Intra-frame
compression treats each frame of a video
segment independently. Several video
compression formats use the intra-frame
method. These include Motion-JPEG, DV,
and MPEG-2 I-frame. Also called spatial
redundancy reduction. Contrast with
inter-frame compression. See also I-frame
(Intra-frame).
IRE unit An arbitrary unit designated by
the Institute of Radio Engineers to define the
amplitude of a video signal. 1 IRE is equal to
approximately 7 mV.
J
JPEG (pronounced "jay-peg") Joint
Photographic Experts Group. A compression
and storage standard used for still, digital
images. See also Motion-JPEG.
K
key effect See alpha key, chroma key, and
luma key.
L
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.
luma key An effect that makes portions of
a foreground image fully or partially
transparent based on the luminance of that
image, so that an underlying image can show
through. See also alpha key and chroma key.
luminance The brightness portion of a
video signal. The luminance of a pixel