THOMSON GRASS VALLEY KayakDD-1, User Manual

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KayakDD - Digital Production Switcher
2.10.4 Clip and Gain
The Clip and Gain operation selects a threshold of the selected key cut video that will
be used to cut the hole in the background video. Clip controls the threshold, and Gain
controls the softness of the key edges and any translucent areas. High portions of the
key cut signal specifies what video is retained, and low portions determine what video
is removed. Intermediate levels specify a soft blend of the background and fill video.
Figure 9 Key Clip, Gain, and Key Control Signal
Clip and Gain control is appropriate for high gain keys (see below), to easily adjust
here the relatively hard transition from background to fill occurs. In this mode,
changing the Clip control moves the threshold up and down without affecting Gain,
which is adjusted separately with its own Gain control.
2.10.5 High Gain, Low Gain, and Unity Gain
A high gain key has a narrow range, creating harder key edges. A low gain key has a
wider range, creating softer key edges. Linear keys typically use minimal gain (also
called unity gain) to completely preserve the soft edges of the keys (
Figure 10 ). Note
that the KayakDD system also supports keys that go below unity gain.
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Figure 10 Keying Gain Values
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