|
|
|
The topology port driver exposes the topology of the audio adapter's mixing hardware. For example, the hardware that mixes the playback streams from the wave renderer and MIDI synthesizer in a typical adapter can be modeled as a set of control nodes (volume, mute, and sum) plus the data paths that connect the nodes. This topology is exposed as a set of controls and mixer lines by the Windows Multimedia mixer API (see Kernel Streaming Topology to Audio Mixer API Translation). The adapter driver provides a corresponding topology miniport driver object that it binds to the topology port driver object to form a topology filter. The port and miniport driver objects communicate with each other through their respective IPortTopology and IMiniportTopology interfaces.