The MMSYSTEM module contains the Media Control Interface, which coordinates activities and communicates with MCI device drivers. Some MCI device drivers, such as those for videodisc players and movie playback services, control the target device directly. Other MCI device drivers, such as those for MIDI services and waveform services, use MMSYSTEM functions to indirectly control the target devices. Finally, some MCI device drivers, such as the MCI Movie Player, provide a high-level interface to other Windows DLLs. The following illustration shows this interaction: