GRASS VALLEY 8995DNC -, Instruction Manual

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8995UPC/DNC/UDX — Instruction Manual 117
Active Format Description
This appendix is provided for a detailed overview of using the Aspect Ratio
controls when Active Format Description (AFD) is present on the input
signal. When AFD is not present on the input signal or has been disabled
on the Aspect Ratio web page, use the Aspect Ratio controls as described in
the main body of the manual (
Aspect Ratio Web Page on page 73 ).
Active Format Description (AFD) is a 4-bit binary code (a0, a1, a3, a4),
which is part of a 10-bit AFD word describing the video picture in terms of
the aspect ratio and other characteristics of the active image within a coded
frame. AFD also includes an aspect ratio (AR) bit stored as b2 which indi-
cates whether the picture is 16:9 (1) or 4:3 (0).
Note The additional information comprising the 10-bit AFD word, called Bar data,
describing the unused areas of active video is currently not supported.
The active image is the portion of the video picture area that is being uti-
lized for program content. The coded frame is the video frame as coded in
a compressed bitstream for emission as shown in
Figure 63 . This manual
uses the term coded frame to describe the area including the active video
defined by the format standard being described by the AFD.
Figure 63. Active Image and Coded Frame
When the module reports the presence of an AFD coded input in the AFD
Status reporting section on the Aspect Ratio web page, the AFD Input Line,
the Input Aspect Ratio, and the binary AFD Input Code are reported (see
Figure 66 on page 120 ).
The presence of the resulting output signal is also reported as well as the
AFD Output line, Output Aspect Ratio, and binary AFD Output Code. The
output translation of the Input to Output code is based on the up or down
conversion and the aspect ratio settings. When a 4:3 or 16:9 input signal is
passed through the module with no up, down, or cross conversion, the
AFD Input Code will be the same as the AFD Output Code.
Active Image 4:3 Pilla r Box
(i ns ide dotted li n e s )
Coded F r ame
16:9