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WM_CAP_SET_PREVIEW message

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The WM_CAP_SET_PREVIEW message enables or disables preview mode. In preview mode, frames are transferred from the capture hardware to system memory and then displayed in the capture window using GDI functions. You can send this message explicitly or by using the capPreview macro.

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

Parameters

f

Preview flag. Specify TRUE for this parameter to enable preview mode or FALSE to disable it.

Return Value

Returns TRUE if successful or FALSE otherwise.

Remarks

The preview mode uses substantial CPU resources. Applications can disable preview or lower the preview rate when another application has the focus. The fLiveWindow member of the CAPSTATUS structure indicates if preview mode is currently enabled.

Enabling preview mode automatically disables overlay 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