DigitalVideoAndHDTVAlgorithmsAndInterfaces.pdf

Y’/C629,
Y’/C688
Y’C 1 C 2
Y’C BC R
Analog luma, Y’ (not luminance), accompanied by a modulated
chroma signal, C, quadrature modulated at approximately the
subcarrier frequency indicated in kilohertz. Used as an interface
standard for dubbing, editing, or timebase correction of certain
color-under VCRs. Typically has unstable timebase and incoherent
color subcarrier.
Luma, Y’ (not luminance), accompanied by two color difference
signals, where the components C 1 and C 2 are specified (or evident
from context) and are not necessarily any of the common pairs
[B’-Y’, R’-Y’], [P B, P R], [C B, C R], [U, V], or [I, Q].
1. In video, MPEG, and M-JPEG, luma, Y’ (not luminance), accompanied
by two color difference components scaled independently
to have a peak-to-peak excursion 224 ⁄219 that of the luma excursion.
In an 8-bit Rec. 601 interface, C B and C R are scaled to
a reference excursion of ±112; an offset of +128 is added. See
Luma, on page 636; and C B , C R (1) on page 616.
2. In JPEG/JFIF as used in computing, luma, Y’ (not luminance)
having excursion 0 through 255, accompanied by two color difference
components scaled independently to have a ”full-range”
(128±128) peak-to-peak excursion 256 ⁄255 that of the luma excursion;
pure blue and pure red are clipped. See Luma, on page 636;
and C B , C R (2) on page 616.
Y’IQ Luma, Y’ (not luminance), accompanied by color difference
components I (In-phase) and Q (Quadrature) derived from U and
V by a +33° rotation and an exchange of axes. Historically, NTSC
was formed from color difference components of unequal bandwidth,
where Q was filtered more severely than I. Nowadays
quadrature modulation based on equiband [U, V] color differences
is almost universal and Y’IQ is obsolete, except for 4f SC
NTSC composite digital interface and D-2 composite digital VTRs.
Y’P B P R
Luma, Y’ (not luminance), accompanied by analog [P B , P R ] color
difference components. P historically stood for parallel. The
EBU N10 standard specifies luma excursion of 700 mV and P B P R
excursion of ±350 mV. This standard is used in 576i and in HDTV;
however, different industry standards are usually used for 480i.
See Luma, on page 636; and P B , P R , on page 641.
Y’UV 1. Properly, luma, Y’ (not luminance), and two color difference
components [U, V] scaled for subsequent encoding into a
composite video signal, such as NTSC or PAL. For component
analog video, [U, V] components are inappropriate, and [P B , P R ]
should be used. For component digital video, [U, V] components
are inappropriate, and [C B , C R ] should be used. See Luma, on
page 636; and U, V, on page 649.
2. The notation Y’UV – or, carelessly written, YUV – is often used
to denote any component system employing luma, Y’ (not luminance)
accompanied by two scaled color difference components
based upon B’-Y’ and R’-Y’, where scaling of B’-Y’ and R’-Y’ is
unknown or implicit.
652 DIGITAL VIDEO AND HDTV ALGORITHMS AND INTERFACES