Supporting Overlay Capabilities, Using VCKernel.lib

Kernel-mode video capture drivers support a device’s overlay capabilities by providing a set of functions that VCKernel.lib can call in response to requests from a user-mode driver. If the hardware supports overlay capabilities, the driver must provide the following set of functions:

OverlayFunc 

Enables overlay.

GetOverlayModeFunc 

Returns overlay capabilities.

SetOverlayRectsFunc 

Sets overlay display rectangles.

SetOverlayOffsetFunc 

Sets the overlay offset rectangle that is used for panning.

GetKeyColourFunc 

Returns the overlay area’s current key color.

SetKeyPalIdxFunc 

Sets the overlay area’s key color to a palette index number.

SetKeyRGBFunc 

Sets the overlay area’s key color to an RGB value.