MCI_WINDOW

This message specifies the window and characteristics that a graphic device (such as digital video or video overlay) should use for its display.

Syntax

param1
ULONG ulParam1; /* Message flags. */

param2
PMCI_VID_WINDOW_PARMS pParam2; /* Pointer to window structure. */

Parameters

ulParam1 (ULONG) - input

This parameter can contain any of the following flags:

* MCI_NOTIFY — Posts a notification message when the action completes.

* MCI_WAIT — Does not return control until the action completes.

Digital Video Extensions

* MCI_DGV_MONITOR — Applies the message functions to the monitor window.

* MCI_DGV_WINDOW_HWND — Uses the handle in `hwndDest` as the destination window.

* MCI_DGV_WINDOW_DEFAULT — Switches back to the default video window.

* MCI_DGV_WINDOW_STATE — Uses the `usCmdShow` field to set window state (e.g., `SWP_SHOW`, `SWP_HIDE`). Only applies to the default window.

* MCI_DGV_WINDOW_TEXT — Uses the `pszText` field to set the window caption. Only applies to the default window.

Video Overlay Extensions

* MCI_OVLY_WINDOW_DEFAULT — Uses the default video window.

* MCI_OVLY_WINDOW_HWND — Uses the handle in `hwndDest` as the destination window.

* MCI_OVLY_WINDOW_STATE — Sets the window state using `usCmdShow`. Only applies to the default window.

* MCI_OVLY_WINDOW_TEXT — Sets the window caption using `pszText`. Only applies to the default window.

pParam2 (PMCI_VID_WINDOW_PARMS) - input

A pointer to an MCI_VID_WINDOW_PARMS structure. Device-specific extensions include:

* PMCI_DGV_WINDOW_PARMS — For digital video devices.

* PMCI_OVLY_WINDOW_PARMS — For video overlay devices.

Return Value

rc (ULONG)

* MCIERR_SUCCESS — Success.

* MCIERR_INVALID_DEVICE_ID — Invalid device ID.

* MCIERR_INVALID_FLAG — Invalid flag specified.

* MCIERR_FLAGS_NOT_COMPATIBLE — (e.g., combining `WINDOW_DEFAULT` and `WINDOW_STATE`).

* MCIERR_INSTANCE_INACTIVE — Device instance is inactive.

Remarks

By default, video devices create a window upon opening but keep it hidden until a play command or a show state is received. If an application provides its own window handle via `MCI_DGV_WINDOW_HWND`, it is responsible for handling window painting (updating invalid rectangles).

State and text flags (like `MCI_DGV_WINDOW_STATE`) are provided primarily for the string interface; C/C++ programmers may find it more efficient to use standard Win APIs after retrieving the window handle via MCI_STATUS.

Related Messages

• MCI_WHERE
• MCI_PLAY
• MCI_STATUS

Example Code

The following code illustrates how to redirect video output to an application-supplied window.

    MCI_DGV_WINDOW_PARMS mciWindowParms;
    USHORT usUserParm = 0;
    ULONG  ulReturn;

    /* Initialize structure and set the alternate window handle */
    memset (&mciWindowParms, 0x00, sizeof (MCI_DGV_WINDOW_PARMS));
    mciWindowParms.hwndCallback = hwndNotify;
    mciWindowParms.hwndDest = hwndAlternate; /* The handle to your app window */

    /* Redirect video to the specified HWND */
    ulReturn = mciSendCommand(usDeviceID, MCI_WINDOW,
                      MCI_WAIT | MCI_DGV_WINDOW_HWND,
                      (PVOID)&mciWindowParms,
                      usUserParm);