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MCI_FREEZE

  • Artikel

The MCI_FREEZE command freezes motion on the display. Digital-video, video-overlay, and VCR devices recognize this command.

To send this command, call the mciSendCommand function with the following parameters.

MCIERROR mciSendCommand(
  MCIDEVICEID wDeviceID, 
  MCI_FREEZE, 
  DWORD dwFlags, 
  (DWORD) (LPMCI_GENERIC_PARMS) lpFreeze
);

Parameters

wDeviceID

Device identifier of the MCI device that is to receive the command message.

dwFlags

MCI_NOTIFY, MCI_WAIT, or, for digital-video and VCR devices, MCI_TEST. For information about these flags, see The Wait, Notify, and Test Flags.

lpFreeze

Pointer to an MCI_GENERIC_PARMS structure. (Devices with additional parameters might replace this structure with a device-specific structure.)

Return Values

Returns zero if successful or an error otherwise.

Remarks

The following additional flags are used by the digitalvideo device type:

MCI_DGV_FREEZE_AT

The rc member of the structure identified by lpFreeze contains a valid rectangle. The rectangle specifies a region within the frame buffer that will have the lock mask bit for each pixel turned on. The specified pixels will not be updated until their lock mask bit is turned off. If this flag is not specified, the rectangle defaults to the entire frame buffer. This flag is supported only if the MCI_GETDEVCAPS command returns TRUE for the MCI_DGV_GETDEVCAPS_CAN_LOCK flag.

MCI_DGV_FREEZE_OUTSIDE

The area outside the region specified for the MCI_DGV_FREEZE_AT flag is frozen.

For digital-video devices, the lpFreeze parameter points to an MCI_DGV_FREEZE_PARMS structure.

The following additional flags are used by the vcr device type:

MCI_VCR_FREEZE_FIELD

Freeze only one member of the current frame.

MCI_VCR_FREEZE_FRAME

Freeze both fields of the current frame.

MCI_VCR_FREEZE_INPUT

Freeze the current frame on the screen (used for recording).

MCI_VCR_FREEZE_OUTPUT

Freeze the current frame from the VCR (used with frame capture).

For VCR devices, the lpFreeze parameter points to an MCI_GENERIC_PARMS structure.

The following additional flag is used by the overlay device type:

MCI_OVLY_RECT

The rc member of the structure identified by lpFreeze contains a valid rectangle. If this flag is not specified, the device driver will freeze the entire frame.

For video-overlay devices, the lpFreeze parameter points to an MCI_OVLY_RECT_PARMS structure.

Requirements

**  Windows NT/2000/XP:** Included in Windows NT 3.1 and later.
**  Windows 95/98/Me:** Included in Windows 95 and later.
**  Header:** Declared in Mmsystem.h; include Windows.h.

See Also

MCI, MCI Commands, MCI_DGV_FREEZE_PARMS, MCI_GENERIC_PARMS, MCI_GETDEVCAPS