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capSetCallbackOnFrame

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The capSetCallbackOnFrame macro sets a preview callback function in the application. AVICap calls this procedure when the capture window captures preview frames. You can use this macro or explicitly call the WM_CAP_SET_CALLBACK_FRAME message.

BOOL capSetCallbackOnFrame(
  hwnd,  
  fpProc 
);

Parameters

hwnd

Handle to a capture window.

fpProc

Pointer to the preview callback function, of type capVideoStreamCallback. Specify NULL for this parameter to disable a previously installed callback function.

Return Values

Returns TRUE if successful or FALSE if streaming capture or a single-frame capture session is in progress.

Remarks

The capture window calls the callback function before displaying preview frames. This allows an application to modify the frame if desired. This callback function is not used during streaming video capture.

Requirements

**  Windows NT/2000/XP:** Included in Windows NT 3.1 and later.
**  Windows 95/98/Me:** Included in Windows 95 and later.
**  Header:** Declared in Vfw.h.

See Also

Creating a Frame Callback Function, Video Capture, Video Capture Macros, WM_CAP_SET_CALLBACK_FRAME