capPreview macro (vfw.h)

Article
10/05/2021

The capPreview macro 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 use this macro or explicitly call the WM_CAP_SET_PREVIEW message.

Syntax

void capPreview(
   hwnd,
   f
);

Parameters

hwnd

Handle to a capture window.

f

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

Return value

None

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]
Target Platform	Windows
Header	vfw.h