DigitalVideoAndHDTVAlgorithmsAndInterfaces.pdf

Interstitial 1. Chroma subsampling wherein each subsampled chroma sample
is effectively horizontally positioned halfway between adjacent
luma samples. Interstitial 4:2:0 chroma subsampling is implicit in
the JPEG/JFIF, H.261, and MPEG-1 standards.
2. In television programming, a short element such as a commercial
inserted into or between programs.
IRD Integrated receiver-decoder: A device that receives an RF signal
carrying digital television, and produces an uncompressed video
signal, typically in analog form. An IRD performs demodulation,
demultiplexing, and MPEG-2 decoding. An IRD is typically a settop
device (set top box, STB).
IRE Institute of Radio Engineers, the predecessor of the IEEE.
IRE unit One-hundredth of the excursion from blanking level to reference
white level. Originally standardized by the IRE. In systems having
picture-to-sync ratio of 10:4 (such as ITU-R System M and the
archaic EIA RS-343-A), one IRE unit corresponds to 7 1 ⁄7 mV. In
systems having picture-to-sync ratio of 7:3, one IRE unit corresponds
to exactly 7 mV. In 50 Hz systems, levels are usually
expressed in millivolts and not IRE units.
ITU-R International Telecommunications Union, Radiocommunications
Sector; successor to the Comité Consultatif Internationale des Radiocommunications
(International Radio Consultative Committee,
CCIR): A treaty organization that obtains international agreement
on standards for radio and television broadcasting. The ITU-R BT
series of Recommendations and Reports deals with television.
Although studio standards do not involve radio transmission in
a strict sense, they are used in the international exchange of
programs, so they are under the jurisdiction of ITU-R.
ITU-R Rec. BT. 601, 709 Colloquially, Rec. 601 and Rec. 709; see Rec. 601 and Rec. 709, on
page 643.
JFIF JPEG file interchange format. A file format, adopted by an
industry group led by C-Cube, that encapsulates a JPEG image,
along with a small amount of supplementary data. If you are
presented with an image data file described as JPEG, in all likelihood
it is JFIF.
JPEG 1. Joint Photographic Experts Group: A standards committee,
constituted jointly by the ISO and IEC and formally denoted
ISO/IEC JTC1.
2. A standard, formally denoted ISO/IEC 10918, adopted by
JPEG (1), for the lossy compression of digital still images (either
color or grayscale).
K Unit of absolute temperature, kelvin. Properly written with no
degree sign. In color science, commonly used to quantify color
temperature.
GLOSSARY OF VIDEO SIGNAL TERMS 633