Audio Queue Services

Overview

This document describes Audio Queue Services, a C programming interface in the Audio Toolbox framework, which is part of Core Audio.

An audio queue is a software object you use for recording or playing audio. An audio queue does the work of:

• Connecting to audio hardware

• Managing memory

• Employing codecs, as needed, for compressed audio formats

• Mediating playback or recording

Audio Queue Services enables you to record and play audio in linear PCM, in compressed formats (such as Apple Lossless and AAC), and in other formats for which users have installed codecs. Audio Queue Services also supports scheduled playback and synchronization of multiple audio queues and synchronization of audio with video.

Topics

Creating and Disposing of Audio Queues

• AudioQueueNewOutputWithDispatchQueue(_:_:_:_:_:)
• AudioQueueNewInputWithDispatchQueue(_:_:_:_:_:)
• AudioQueueNewOutput(_:_:_:_:_:_:_:)
• AudioQueueNewInput(_:_:_:_:_:_:_:)
• AudioQueueDispose(_:_:)
• AudioQueueRef
• AudioQueueInputCallbackBlock
• AudioQueueOutputCallbackBlock

Controlling Audio Queues

• AudioQueueStart(_:_:)
• AudioQueuePrime(_:_:_:)
• AudioQueueFlush(_:)
• AudioQueueStop(_:_:)
• AudioQueuePause(_:)
• AudioQueueReset(_:)

Handling Audio Queue Buffers

• AudioQueueAllocateBuffer(_:_:_:)
• AudioQueueAllocateBufferWithPacketDescriptions(_:_:_:_:)
• AudioQueueFreeBuffer(_:_:)
• AudioQueueEnqueueBuffer(_:_:_:_:)
• AudioQueueEnqueueBufferWithParameters(_:_:_:_:_:_:_:_:_:_:)

Tapping the Queue’s Audio

• AudioQueueProcessingTapNew(_:_:_:_:_:_:_:)
• AudioQueueProcessingTapGetQueueTime(_:_:_:)
• AudioQueueProcessingTapGetSourceAudio(_:_:_:_:_:_:)
• AudioQueueProcessingTapDispose(_:)

Manipulating Audio Queue Parameters

• AudioQueueGetParameter(_:_:_:)
• AudioQueueSetParameter(_:_:_:)

Manipulating Audio Queue Properties

• AudioQueueGetProperty(_:_:_:_:)
• AudioQueueSetProperty(_:_:_:_:)
• AudioQueueGetPropertySize(_:_:_:)
• AudioQueueAddPropertyListener(_:_:_:_:)
• AudioQueueRemovePropertyListener(_:_:_:_:)

Managing the Timeline

• AudioQueueCreateTimeline(_:_:)
• AudioQueueDisposeTimeline(_:_:)
• AudioQueueDeviceGetCurrentTime(_:_:)
• AudioQueueDeviceGetNearestStartTime(_:_:_:)
• AudioQueueDeviceTranslateTime(_:_:_:)
• AudioQueueGetCurrentTime(_:_:_:_:)
• AudioQueueTimelineRef

Performing Offline Rendering

• AudioQueueSetOfflineRenderFormat(_:_:_:)
• AudioQueueOfflineRender(_:_:_:_:)

Callbacks

• AudioQueueInputCallback
• AudioQueueOutputCallback
• AudioQueuePropertyListenerProc

Data Types

• AudioQueueChannelAssignment
• AudioQueueProcessingTapFlags
• AudioQueueBuffer
• AudioQueueBufferRef
• AudioQueueLevelMeterState
• AudioQueueParameterEvent
• AudioQueueParameterID
• AudioQueueParameterValue
• AudioQueueProcessingTapCallback
• AudioQueueProcessingTapRef

Structures

• AudioUnitConnection
• AudioUnitEvent
• AudioUnitExternalBuffer
• AudioUnitFrequencyResponseBin
• AudioUnitMeterClipping
• AudioUnitMIDIControlMapping
• AudioUnitOtherPluginDesc
• AudioUnitParameter
• AudioUnitParameterEvent
• AudioUnitParameterHistoryInfo
• AudioUnitParameterNameInfo
• AudioUnitParameterIDName
• AudioUnitParameterInfo
• AudioUnitParameterOptions
• AudioUnitParameterStringFromValue
• AudioUnitParameterValueFromString
• AudioUnitParameterValueName
• AudioUnitParameterValueTranslation
• AudioUnitPresetMAS_SettingData
• AudioUnitPresetMAS_Settings
• AudioUnitProperty
• AudioUnitRenderActionFlags
• AU3DMixerRenderingFlags
• AUChannelInfo
• AUDependentParameter
• AUDistanceAttenuationData
• AUHostIdentifier
• AUHostTransportStateFlags
• AUHostVersionIdentifier
• AUInputSamplesInOutputCallbackStruct
• AUMIDIEvent
• AUMIDIOutputCallbackStruct
• AUNumVersion
• AUParameterAutomationEvent
• AUParameterEvent
• AUParameterMIDIMapping
• AUParameterMIDIMappingFlags
• AUPreset
• AUPresetEvent
• AURecordedParameterEvent
• AURenderCallbackStruct
• AURenderEvent
• AURenderEventHeader
• AUSamplerBankPresetData
• AUSamplerInstrumentData
• AUScheduledAudioSliceFlags
• AUSpatialMixerRenderingFlags

Enumerations

• AudioQueueProcessingTapFlags
• Anonymous
• Audio Queue Time Pitch Algorithms
• Audio Queue Property IDs
• Audio Queue Property IDs
• Audio Queue Hardware Codec Policy

Constants

• AudioQueuePropertyID
• Audio Queue Parameters
• Hardware Codec Policy Keys

Result Codes

• kAudioQueueErr_InvalidBuffer
• kAudioQueueErr_BufferEmpty
• kAudioQueueErr_DisposalPending
• kAudioQueueErr_InvalidProperty
• kAudioQueueErr_InvalidPropertySize
• kAudioQueueErr_InvalidParameter
• kAudioQueueErr_CannotStart
• kAudioQueueErr_InvalidDevice
• kAudioQueueErr_BufferInQueue
• kAudioQueueErr_InvalidRunState
• kAudioQueueErr_InvalidQueueType
• kAudioQueueErr_Permissions
• kAudioQueueErr_InvalidPropertyValue
• kAudioQueueErr_PrimeTimedOut
• kAudioQueueErr_CodecNotFound
• kAudioQueueErr_InvalidCodecAccess
• kAudioQueueErr_QueueInvalidated
• kAudioQueueErr_RecordUnderrun
• kAudioQueueErr_EnqueueDuringReset
• kAudioQueueErr_InvalidOfflineMode
• kAudioFormatUnsupportedDataFormatError

See Also

Playback and Recording

• Audio Services
• Music Player
• Anchoring sound to a window or volume