Extended Command Messages

Extended command messages apply to particular device types such as animation devices. Device types with extended commands have capabilities that are not present in most types of MCI devices. Many of the required and basic commands are extended to use the capabilities of a device. MCI has the following types of extended commands:

The extended commands are summarized in this section. The details of operation are included in the MCI reference section of this chapter. Use these commands only if they apply to your device. If you do use an extended command, it must support the flags that are common to all devices using the command. If your device driver does not support an extended command, return MCIERR_UNRECOGNIZED_COMMAND.

Extended Commands for Working with MCI Element Files

MCI devices that let you edit data can have extended commands for manipulating data. Applications send the following commands to devices that support editing:

MCI Message

Description

MCI_COPY

Copies data from the MCI element to the Clipboard.

MCI_CUT

Moves data from the MCI element to the Clipboard.

MCI_DELETE

Removes data from the MCI element.

MCI_PASTE

Pastes data from the Clipboard to the MCI element.


Extended Commands for Device Operation and Positioning

MCI devices can have operating capabilities that apply only to a device type or that apply to a device with unique features. Applications send the following commands to devices that have specialized operating capabilities:

MCI Message

Description

MCI_CUE

Cue a device for playback or recording.

MCI_ESCAPE

Sends a string command directly to a device handler.

MCI_RESUME

Continue playback or recording previously paused.

MCI_SPIN

Start or stop spinning a rotating media device such as a laserdisc.

MCI_STEP

Step a device one or more frames.


Extended Command for Windowed Video Devices

Video devices that display data in a window on the computer display can have MCI commands for controlling the video display and window. These devices include animation movie players and video overlay devices. Applications send the following commands video devices that display images in a window:

MCI Message

Description

MCI_FREEZE

Stops video capture.

MCI_PUT

Defines a source or destination clipping rectangle.

MCI_REALIZE

Has a graphic device to realize its palette.

MCI_UNFREEZE

Restores video capture.

MCI_UPDATE

Has a graphic device update or paint the current frame.

MCI_WHERE

Determines the extent of a clipping rectangle.

MCI_WINDOW

Specifies a window and the window characteristics used for display.