WM_CAP_SET_CALLBACK_FRAME

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

WM_CAP_SET_CALLBACK_FRAME 
wParam = (WPARAM) 0; 
lParam = (LPARAM) (LPVOID) (fpProc); 
 

Parameters

fpProc

Address of the preview callback function. 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.

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in vfw.h.

See Also

Video Capture Overview, Video Capture Messages, capSetCallbackOnFrame