The MCIWNDM_PUT_SOURCE message redefines the coordinates of the source rectangle used for cropping the images of an AVI file during playback. You can send this message explicitly or by using the MCIWndPutSource macro.
MCIWNDM_PUT_SOURCE
wParam = 0;
lParam = (LPARAM) (LPRECT) prc;
Returns zero if successful or an error otherwise.
Windows NT: Requires version 3.1 or later.
Windows: Requires Windows 95 or later.
Windows CE: Unsupported.
Header: Declared in vfw.h.
MCIWnd Window Class Overview, MCIWnd Messages, MCIWndPutSource, RECT