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WM_CAP_SET_OVERLAY message

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The WM_CAP_SET_OVERLAY message enables or disables overlay mode. In overlay mode, video is displayed using hardware overlay. You can send this message explicitly or by using the capOverlay macro.

WM_CAP_SET_OVERLAY 
wParam = (WPARAM) (BOOL) (f); 
lParam = 0L;

Parameters

f

Overlay flag. Specify TRUE for this parameter to enable overlay mode or FALSE to disable it.

Return Value

Returns TRUE if successful or FALSE otherwise.

Remarks

Using an overlay does not require CPU resources.

The fHasOverlay member of the CAPDRIVERCAPS structure indicates whether the device is capable of overlay. The fOverlayWindow member of the CAPSTATUS structure indicates whether overlay mode is currently enabled.

Enabling overlay mode automatically disables preview mode.

Requirements

Requirement Value
Minimum supported client
 Windows 2000 Professional [desktop apps only]
Minimum supported server
 Windows 2000 Server [desktop apps only]
Header
Vfw.h

See also

Video Capture

Video Capture Messages