MIDI Port Driver

The MIDI port driver manages a MIDI synthesizer or capture device. The adapter driver provides a corresponding MIDI miniport driver that binds to the MIDI port driver object to form a MIDI filter (see MIDI and DirectMusic Filters) that can capture or render a MIDI stream.

The MIDI port driver exposes an IPortMidi interface to the miniport driver. IPortMidi inherits the methods in base interface IPort. IPortMidi provides the following additional methods:

IPortMidi::Notify

Notifies the port driver that the MIDI synthesizer or capture device has advanced to a new position in the MIDI stream.

IPortMidi::RegisterServiceGroup

Registers a service group object with the port driver.

A service group contains a list of one or more service routines that are to be called when the miniport driver calls Notify; for more information, see Service Sink and Service Group Objects.

The MIDI port and miniport driver objects communicate with each other through their respective IPortMidi and IMiniportMidi interfaces. The miniport driver uses the port driver's IPortMidi interface to notify the port driver of hardware interrupts. In addition, the port driver communicates with the miniport driver's stream objects through their IMiniportMidiStream interfaces.

In Windows XP and later, the IPortMidi and IPortDMus interfaces are both implemented in a single internal driver module. This consolidation is facilitated by the similarity of these two interfaces. For example, the same methods are defined for both interfaces. Applications written for previous versions of Windows should see no change in the behavior of the IPortMidi and IPortDMus interfaces resulting from consolidation of the MIDI and DMus port drivers.

 

 

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