the
analog luminanceand
color-
difference components of a
color image (in
digitized form, as
Y, Cr, Cb, in
JPEG) or
video (
NTSC and
PAL). (or
hologram perhaps, sometime in the future)
Y=Analog Luminance,
R-Y=the red signal component minus the luminance,
B-Y=the blue signal component minus the luminance,
the parentheses are there because people who devise methods of encoding images get a little loony after a while...