DigitalVideoAndHDTVAlgorithmsAndInterfaces.pdf

Square sampling
Component 4:2:2
Rec. 601 (“D-1”)
Composite 4fsc
(“D-2”)
ITU-R Rec. BT.601-5, Studio
encoding parameters of digital television
for standard 4:3 and widescreen
16:9 aspect ratios.
480i29.97 SCANNING 576i25 SCANNING
780
858
910
Figure 11.1 indicates S TL and S AL for each standard. The
S AL values are the result of some complicated issues to
be discussed in Choice of S AL and S PW parameters on
page 325. For details concerning my reference to 483
active lines (L A ) in 480i systems, see Picture lines, on
page 324.
Figure 11.2 above shows the standard 480i29.97 and
576i25 digital video sampling rates, and the color
coding usually associated with each of these standards.
The 4:2:2, Y’C BC R system for SDTV is standardized in
Recommendation BT. 601 of the ITU Radiocommunication
Sector (formerly CCIR). I call it Rec. 601.
With one exception, all of the sampling systems in
Figure 11.2 have a whole number of samples per total
line; these systems are line-locked. The exception is
composite 4f SC PAL sampling, which has a noninteger
number (1135 4 ⁄625) of samples per total line; this
creates a huge nuisance for the system designer.
CHAPTER 11 INTRODUCTION TO COMPONENT SDTV 97
944
R’G’B’
12 3 ⁄ 11 MHz
(≈12.272727) 14.75 MHz
14 7 ⁄ 22 MHz
(≈14.31818)
Y’C B C R
Y’IQ
NTSC
864
13.5 MHz 13.5 MHz
1135 4 ⁄ 625
R’G’B’
Y’C B C R
Y’UV
PAL
17.734475 MHz
Figure 11.2 SDTV sample rates are shown for six different 4:3 standards, along with the usual
color coding for each standard. There is no realtime studio interface standard for square-sampled
SDTV. The D-1 and D-2 designations properly apply to videotape formats.