DigitalVideoAndHDTVAlgorithmsAndInterfaces.pdf

2. In traditional video usage, the process of taking component
video input (e.g., Y’C B C R or R’G’B’), performing chroma modulation
and luma/chroma summation, and producing composite
video (e.g., NTSC or PAL).
3. In modern video usage, the processing of uncompressed image
data to produce a compressed bitstream (such as in JPEG,
M-JPEG, or MPEG compression).
Equalization 1. The correction of undesired frequency or phase response.
Coaxial cable introduces a high-frequency rolloff that is dependent
upon cable length and proportional to 1
f
(pronounced one
over root f ); this is corrected by a subsystem called an equalizer.
A naively designed analog lowpass filter, or a simple digital IIR
filter, has poor phase response; this can be corrected by an equalizer
filter section.
2. Equalization pulse; see below.
Equalization pulse A sync pulse, part of vertical sync, that is approximately half the
duration of a normal sync and occurs at 0 H or halfway between
two 0 H data. The original purpose of equalization pulses was to
eliminate the line pairing that would otherwise occur with cheap,
passive sync separator circuits. Equalization pulses are unnecessary
today, except for reverse compatibility.
Error concealment Masking, by playback or receiver circuits, of errors introduced in
recording or transmission. Concealment is enabled by the playback
or receiver circuits’ detection of errors by using ECC codes.
Concealment is accomplished by replacing errored samples by
interpolated (estimated) signal information.
Error correction Perfect correction, by playback or receiver circuits, of errors introduced
in recording or transmission. Correction is effected by the
decoder’s using the redundant ECC information inserted by the
recorder or transmitter to perfectly reconstruct the errored bits.
Even field Historically, in 480i (interlaced) scanning, the field whose first
broad pulse starts halfway between two line syncs. Compare Odd
field, on page 639. The terms odd and even should be avoided,
and first and second used instead.
Excursion The amplitude difference between two levels. Unless otherwise
noted, reference excursion.
Exponential function A function of the form y = a x , where a is constant. Exponential
functions are rarely used in video. Gamma correction is a modified
power function, and not an exponential function as is sometimes
claimed.
FEC Forward error-correction: A synonym for ECC (see page 627),
particularly when used in transmission or video recording systems.
Field In interlaced scanning, the smallest time interval that contains
a set of scanning lines covering the height of the entire picture,
628 DIGITAL VIDEO AND HDTV ALGORITHMS AND INTERFACES