Document Revision History

This table describes the changes to Audio Unit Properties Reference.

2012-12-13Clarified discussion of voice processing I/O audio unit properties.

Added descriptions of new APIs for iOS 4.3: AudioUnitParameterHistoryInfo, kAudioUnitParameterFlag_PlotHistory, and kAudioUnitProperty_ParameterHistoryInfo.


Added descriptions of additional Voice-Processing I/O unit APIs: VoiceIOFarEndVersionInfo, kAUVoiceIOProperty_FarEndVersionInfo, kVoiceIOFarEndAUVersion_RequiresBackwardCompatibility, and kVoiceIOFarEndAUVersion_ThirdParty.


Improved descriptions for the kAudioUnitProperty_MaximumFramesPerSlice and kAudioUnitProperty_StreamFormat properties.


Additional minor improvements.


Added descriptions for the kAUVoiceIOProperty_VoiceProcessingQuality and kAUVoiceIOProperty_MuteOutput properties.


Clarified the description of the kAudioOutputUnitProperty_EnableIO property.


Added descriptions for the constants in “Mixer Audio Unit Properties.”


Added descriptions for the constants in “Offline Audio Unit Properties.”


Added information on memory management to several properties: kAudioUnitProperty_ClassInfo, kAudioUnitProperty_ElementName, kAudioUnitProperty_PresentPreset, kAudioUnitProperty_ParameterValueStrings, kAudioUnitProperty_FactoryPresets, kAudioUnitProperty_PreflightName.


Updated for iOS 3.0.


Improved description of AudioUnitParameterNameInfo. Added descriptions for constants in “Voice-Processing I/O Audio Unit Properties” enumeration.


Updated for iOS 2.1. Improved formatting for declarations.


New document that describes the audio unit properties in iOS and OS X.