GRASS VALLEY EDIUS VERSION 5.1 User Reference Manual page 554

Section 6 — Effects and Titles
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If "Outside Rect. Enable" is selected, luminancekey settings are applied
within the rectangular area only and the area outside the rectangle show
the original video.
Figure 647. Luminancekey Rectangle Enabled
Invert
Selecting this option inverts the range to which luminancekey settings are
applied. The histogram will show that the settings are applied to the areas
outside the slope lines.
All Calculation
Select this option to calculate the area outside the range specified by "Out-
side Rect. Enable."
KeyFrame Setting Tab
When this tab is selected, the settings shown in Figure 648 appear.
EDIUS — User Reference Guide