MCI, playing an AVI, using my own window

I am using the Media Control Interface to play an AVI file.  I can easily open, play and close the AVI file.  By default the video plays in it's own window that is created on play.

This is all fine--but unfortunately I want to play the AVI file within my own window.  To do this, I have done the following after issuing the open command:

  MCI_DGV_WINDOW_PARMS params;
  params.hWnd = wnd.m_hWnd;
  if (mciSendCommand(m_OpenParams.wDeviceID,
                       MCI_WINDOW,
                       MCI_DGV_WINDOW_HWND,
                       (unsigned long)&params) != 0)
  {
    return FALSE; // some error
  }

This works... well sort of.  When the video initially displays, it appears fine.  But as soon as it begins to play, the video appears garbled.

My guess is I might need to handle screen updates or something.  Unfortunately I can't find any documentation or samples for this.

Thanks in advance.