MOTU V4HD User Manual page 44

Video Source menu
The Video Source menu (Figure 6-3) is important
because this is where you choose the video input
from which the V4HD will convert and capture.
Choose any SD or HD source (Figure 6-5), and the
V4HD converts it to all output formats and sends it
over Firewire to the computer.
Figure 6-5: The Video Source menu.
When you choose a source, the V4HD can auto-
detect the frame rate and format of the incoming
video (see "Auto Detect Input Format" on page 48).
Format Conversion menu
The Format Conversion menu (Figure 6-3) lets you
choose the formatting for SD to HD up conversion
or HD to SD down conversion. The format
conversion color bar diagram (Figure 6-3)
provides a thumbnail illustrating the resulting
formatting. The color bars represent the original
source signal and the boxed boundary represents
the destination frame.
HD to SD down conversion formats
When an HD source is chosen in the Video Source
menu (Figure 6-5), the format conversion menu
appears along the SD signal path, as demonstrated
in Figure 6-3. The menu provides the following
HD to SD down conversion formatting options:
Figure 6-6: HD to SD down conversion formatting options.
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Letterbox (HD to SD)
Letterboxing is the standard practice of
conforming widescreen film images such as film or
HD to an SD video frame while preserving the
original aspect ratio. Since the SD video frame is
more square than the widescreen frame, the
resulting image has "black bars" or mattes above
and below the image (Figure 6-7).
Figure 6-7: Letterbox formatting.
The Letterbox option (Figure 6-6) preserves the
aspect ratio of the HD source signal while filling
the SD frame edge to edge (left to right). Black bars
are added to fill the unused portion of the frame
above and below (Figure 6-7). No cropping occurs
and the full image is preserved.
14:9 Letterbox (HD to SD)
With the 14:9 Letterbox option (Figure 6-6), aspect
ratio is preserved (Figure 6-8) and some cropping
occurs on the left and right edge, but not as much
as in Full Screen mode (explained below). In
addition, the letterbox bars are smaller. In essence,
this mode scales the image larger than letterbox
mode, but not as much as Full Screen mode, with
less left- and right-edge cropping than Full Screen
mode and smaller letterbox bars.
Figure 6-8: 14:9 letterbox formatting.
Source HD image (color bars)
SD frame
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