
FS2 Frame Synchronizer/Converter v3.0 62 www.aja.com
resulting picture. For example, 14x9 is not precisely 14x9. However, picture scaling
is such that the visual effect closely resembles an HD-to-SD downconvert.
Crop
(default)
Anamorphic
14:9
Auto AFD
Letterbox
Image is cropped to fit new screen size.
HD image is converted to full-screen SD with a 16x9 aspect ratio
(anamorphic).
Image is reduced slightly with aspect ratio preserved. Black is added
top and bottom, and the left and right sides are cropped.
Automatically selects the best Downconvert mode based on the
input video’s Active Format Description (AFD) code. If the input
video is not carrying an AFD VANC code, the Downconverter
defaults to the mode specified in parameter menu
16.3
Downconvert AFD Default
.
Image is reduced with black top and bottom added to image area,
with the aspect ratio preserved.
Active Format Description (AFD) codes are carried in the vertical ancillary
(VANC) portion of HD SDI video signals, specified in SMPTE 2016 as follows: “AFD
information is intended to guide DTV receivers and/or intermediate professional
video equipment regarding the display of video of one aspect ratio on a display
of another aspect ratio.”
In the FS2 Downconverter, the AFD code on the video input can be used to guide
the Downconverter in choosing which mode to use to best display the important
content of the input 16:9 HD video on the 4:3 SD output. For example, if the input
AFD code is 10 (Full Frame), it means that the input video has important picture
information throughout the full 16:9 frame, so the Downconverter should use
Letterbox mode to be sure none of the content is cropped off. An AFD code of 9
(Pillarbox) says that the input video only has content within the center 4:3 area of
the picture (usually because it originally came from an Upconverted SD signal) so
the Downconverter Crop mode would be the best choice. There are 16 possible
HD AFD codes, of which 8 are in common use. The FS2 does not process or use SD
AFD codes.
FS2 AFD processing (passing, removing, and re-inserting) occurs based on the
setting of parameters 7, 5.4, 16.1, and 16.2.
Auto AFD mode fully defines the size, position, and aspect ratio of the output
raster. Thus, when in Auto AFD mode (Output Format set to an SD format, with
an HD video input, and Downconvert Mode set to Auto AFD), any Custom Size/
Pos settings are ignored, and those menus (13.0 - 13.8) are hidden. Likewise, when
in Auto AFD mode, any Region Of Interest settings are ignored, and those menus
(14.0 - 14.4) are hidden.