The MCI command set is designed to provide a generic core set of commands to control different types of media devices. For example, MCI uses the same command to begin playback of a waveform audio file, a videodisc track, and an animation sequence. Some types of devices have unique capabilities, such as the capability of an animation player to use a frame-based time format. For such devices, MCI provides extended commands that are unique to a particular type of device.
The commands in the command-string interface provide a good overview of the MCI command set. Each of these commands is represented by a similar command in the command-message interface. For example, the equivalent command message for the close command is the MCI_CLOSE message.
The following table is an overview of some of the commonly used commands:
| Command | Description |
| capability | Requests information about the capabilities of a device. |
| close | Closes a device after it has been used. |
| info | Requests information about a device such as a description of the hardware associated with the device. |
| open | Opens and initializes a device for use. |
| pause | Pauses playing or recording on a device. |
| play | Begins playing on a device. |
| record | Begins recording on a device. |
| resume | Resumes playing or recording on a paused device. |
| seek | Changes the current position in the media. |
| set | Changes control settings on the device such as the time format it is using. |
| status | Requests information about the status of a device such as whether it is playing or paused. |
| stop | Stops playing or recording on a device. |
For a complete list of commands, see the Multimedia Programmer's Reference. The MCI command messages are in the message overview and message reference chapters—the MCI command strings are in a separate chapter.