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3:2
pull-down: Method used to map the 24 fps of film onto the 30 fps
(60fields) of 525-line TV, so that one film frame occupies three TV
fields, the next two, etc. It means the two fields of every other TV
frame come from different film frames making operations such as
rotoscoping impossible, and requiring care in editing. Some
sophisticated equipment can unravel the 3:2 sequence to allow
frame-by-frame treatment and subsequently recompose 3:2. The 3:2
sequence repeats every five TV frames and four film frames, the latter
identified as A-D. Only film frame A is fully on a TV frame and so
exists at one time code only, making it the editable point of the video
sequence.
4fsc:
Four times the frequency of SC (subcarrier). The sampling rate of aD2
digital video signal with respect to the subcarrier frequency of an
NTSC or PAL analog video signal. The 4fsc frequency is 14.3 MHz in
NTSC and 17.7 MHz in PAL.
4:1:1:
This is a set of sampling frequencies in the ratio 4:1:1, used to
digitize the luminance and color difference components (Y, R-Y, B-Y)
of a video signal. The four represents 13.5 MHz, the sampling
frequency of Y, and the ones each 3.75 MHz for R-Y and B-Y.With the
color information sampled at half the rate of the 4:2:2 system, this
is generally used as a more economical form of sampling for 525-line
picture formats. Both luminance and color difference are still sampled
on
every line. But the latter has half the horizontal resolution of
4:2:2, while the vertical resolution of the color information is
maintained. For 525-line pictures, this means the color is fairly
equally resolved in horizontal and vertical directions.
4:2:0:
A sampling system used to digitize the luminance and color difference
components (Y, R-Y, B-Y) of a video signal. The four represents the
13.5 MHz sampling frequency of Y, while the R-Y and B-Y are sampled at
6.75 MHz--effectively between every other line only (one line is
sampled at 4:0:0, luminance only, and the next at 4:2:2). This is
generally used as a more economical system than 4:2:2 sampling for
625-line formats so that the color signals have a reasonably even
resolution in the vertical and horizontal
directions for that format.
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4:2:2:
A commonly used term for a component digital video format. A ratio of
sampling frequencies used to digitize the luminance and color
difference components (Y, R-Y, B-Y) of a video signal. It is generally
used as shorthand for ITU-R 601. The term 4:2:2 describes that for
every four samples of Y, there are two samples each of R-Y and B-Y,
giving more chrominance bandwidth in relation to luminance compared to
4:1:1 sampling. ITU-R 601, 4:2:2 is the standard for digital studio
equipment and the terms "4:2:2" and "601" are
commonly (but technically incorrectly) used synonymously. The sampling
frequency of Y is 13.5 MHz and that of R-Y and B-Y is each 6.75 MHz
providing a maximum color bandwidth of 3.37 MHz--enough for
high-quality chromakeying. The format specifies eight bits of
resolution. The details of the format are specified in the ITU-R
BT.601-2 standard document. See also: ITU-R BT.601-2.
4:2:2:4:
Same as 4:2:2, but with the addition of a key channel that is sampled
four times for every four samples of the luminance channel.
4:4:4:
Similar to 4:2:2, except that for every four luminance samples,
the color channels are also sampled four times.
4:4:4:4:
Similar to 4:2:2:4, except that for every four luminance samples, the
color and key channels are also sampled four times
48sF:
48 segmented frames. The process of taking 24-frame progressive images
and deconstructing them to produce 48 interlaced frames each with half
of the number of lines of resolution to allow some HDTV processors to
pass the signal and for viewing on an interlaced monitor without
flicker.
5.1:
A type of surround sound. Six discrete audio channels are used: Left,
Center, Right, Left Rear (or side) Surround, Right Rear (or side)
Surround, and a subwoofer (considered the ".1" as it is
limited in bandwidth). See also:
Dolby Digital.
601:
See: ITU-R BT.601-2.
8-VSB:
Eight discrete amplitude level vestigial side-band broadcast
transmission technology, used in the ATSC digital television
transmission standard. See also: ATSC, VSB and the Engineering &
Transmission chapter.
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