DigitalVideoAndHDTVAlgorithmsAndInterfaces.pdf

Vertical interval video lines do not convey picture information.
They may convey ancillary or other signals
either related or unrelated to the picture.
Figure 47.2 overleaf shows details of the vertical sync
structure; this waveform diagram is the analog of
Table 47.2, on page 559.
Picture center, aspect ratio, and blanking
The center of the picture is located midway between
the central two of the 1920 active samples (between
samples 959 and 960), and midway between the
central two 1080 picture lines (between lines 581 and
582 in a progressive system, and between lines 290 and
853 in an interlaced system).
Aspect ratio is defined to be 16:9 with respect to the
production aperture of 1920×1080.
In Transition samples, on page 323, I mentioned that it
is necessary to avoid, at the start of a line, an instantaneous
transition from blanking to picture information.
A clean aperture pixel array 1888 samples wide and
1062 lines high, centered on the production aperture,
should remain subjectively uncontaminated by edge
transients.
Relationship to SMPTE 240M (1035i) scanning
SMPTE 240M defines the now-obsolete 1035i30 and
1035i29.97 systems, having 1035 picture lines. The
first field has 517 picture lines starting at line 41. The
second field has 518 picture lines starting with the top
line of the picture at line 603 and including the bottom
line of the frame at line 1120.
Aspect ratio is defined to be 16:9 with respect to the
production aperture of 1920×1035. The clean aperture
pixel array is 1888 samples wide and 1017 lines high,
centered on the production aperture.
At a digital interface, 1035i signals are distinguished by
the onset of picture as indicated by the V-bit; see
Table 47.2, on page 559.
CHAPTER 47 1920 × 1080 HDTV 563