Datavideo VGB-4000, Instruction Manual

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6. How to Use the Built-in DVK-400 Holdout Mask Function of the VGB-4000
The holdout mask allows you to define the area of the image that would remain unkeyed, for example a
green area on the TV screen. In this section, we will show you how you can cover the green area of the
image that should be kept.
To understand how the holdout mask works, you need to first understand the layer order on the DVK-400
shown in the diagram below. The holdout mask sits between the AUX Lumakey layer and the foreground
image, therefore, by enabling the holdout mask, you are preventing the masked area of the foreground
image from being chromakeyed thus preserving the image layers overall.