wParam = (DWORD) lFrom;
lParam = (DWORD) lTo;
Provides the start and end times of a play operation to a rendering driver.
This message precedes any frame data sent to the rendering driver.
Units for wParam and lParam are specified with ICM_DRAW_BEGIN. For video data this is normally a frame number. For more information about the playback rate, see the dwRate and dwScale members of ICDRAWBEGIN.
If the end time is less than the start time, the playback direction is reversed.
ICM_DRAW, ICM_DRAW_BEGIN, ICM_DRAW_START, ICM_DRAW_STOP, ICM_DRAW_STOP_PLAY, ICDRAWBEGIN