AudioUnit Framework

The AudioUnit.framework publishes the API for applications that want to use Audio Units. These headers define the expected behaviour of Audio Units.

AudioUnit.h
AudioUnit.r
Are umbrella headers that includes all of the headers that are found in this framework.
AUComponent.h
Defines the complete API for the Audio Unit component, including component types, functions declarations, etc.
AUNTComponent.h
Defines those API that are unique to the first version (V1) of the Audio Unit API, whereas AUComponent.h describes version 2 (V2). The differences between these two are discussed throughout this document and are also outlined specifically below.
AUComponent.r
AUNTComponent.r
Contain resource definitions that are needed when building custom Audio Units.
AudioUnitProperties.h
Defines the properties, and supporting structures, that are used by Audio Units.
AudioUnitParameters.h
Defines constants for the parameters that are defined by the Audio Units that Apple ships.
MusicDevice.h
Defines the additional API that adds to the base-level Audio Unit extensions that are appropriate for Software Synthesizers.
AudioOutputUnit.h
Defines additional selectors for Audio Units that provide the semantic for starting and stopping a processing graph.
AudioUnitCarbonView.h
AudioUnitCarbonView.r
These provide the API (and resource definitions for implementations of the API) to present a view that is associated with an Audio Unit. This includes a generic view component that is provided by Apple for effect units.
AudioCodec.h
AudioCodecs are another type of component. Essentially where Audio Units will deal primarily with PCM audio data, AudioCodecs' primary role is to do audio data transformations (for example an decoding an AAC stream into PCM audio data). These components are dealt with in a separate document.