# Audio Converter Services Convert between linear PCM audio formats, and between linear PCM and compressed formats. ## Discussion Audio converter objects convert between various linear PCM audio formats. They can also convert between linear PCM and compressed formats. Supported transformations include the following: - PCM bit depth - PCM sample rate - PCM floating point to and from PCM integer - PCM interleaved to and from PCM deinterleaved - PCM to and from compressed formats A single audio converter may perform more than one of the listed transformations. ## Topics ### Managing Audio Converter Objects [`AudioConverterNew(_:_:_:)`](/documentation/AudioToolbox/AudioConverterNew(_:_:_:)) Creates a new audio converter object based on specified audio formats. [`AudioConverterNewSpecific(_:_:_:_:_:)`](/documentation/AudioToolbox/AudioConverterNewSpecific(_:_:_:_:_:)) Creates a new audio converter object using a specified codec. [`AudioConverterReset(_:)`](/documentation/AudioToolbox/AudioConverterReset(_:)) Resets an audio converter object, clearing and flushing its buffers. [`AudioConverterDispose(_:)`](/documentation/AudioToolbox/AudioConverterDispose(_:)) Disposes of an audio converter object. ### Configuring Audio Converter Properties [`AudioConverterGetProperty(_:_:_:_:)`](/documentation/AudioToolbox/AudioConverterGetProperty(_:_:_:_:)) Gets an audio converter property value. [`AudioConverterGetPropertyInfo(_:_:_:_:)`](/documentation/AudioToolbox/AudioConverterGetPropertyInfo(_:_:_:_:)) Gets information about an audio converter property. [`AudioConverterSetProperty(_:_:_:_:)`](/documentation/AudioToolbox/AudioConverterSetProperty(_:_:_:_:)) Sets the value of an audio converter object property. ### Performing Conversions [Encoding and decoding audio](/documentation/AudioToolbox/encoding-and-decoding-audio) Convert audio formats to efficiently manage data and quality. [`AudioConverterConvertBuffer(_:_:_:_:_:)`](/documentation/AudioToolbox/AudioConverterConvertBuffer(_:_:_:_:_:)) Converts audio data from one linear PCM format to another. [`AudioConverterFillComplexBuffer(_:_:_:_:_:_:)`](/documentation/AudioToolbox/AudioConverterFillComplexBuffer(_:_:_:_:_:_:)) Converts audio data supplied by a callback function, supporting non-interleaved and packetized formats. [`AudioConverterConvertComplexBuffer(_:_:_:_:)`](/documentation/AudioToolbox/AudioConverterConvertComplexBuffer(_:_:_:_:)) Converts audio data from one linear PCM format to another, where both use the same sample rate. ### Deprecated Functions [`AudioConverterFillBuffer`](/documentation/AudioToolbox/AudioConverterFillBuffer) ### Callbacks [`AudioConverterComplexInputDataProc`](/documentation/AudioToolbox/AudioConverterComplexInputDataProc) Supplies input data to the [`AudioConverterFillComplexBuffer(_:_:_:_:_:_:)`](/documentation/AudioToolbox/AudioConverterFillComplexBuffer(_:_:_:_:_:_:)) function. [`AudioConverterInputDataProc`](/documentation/AudioToolbox/AudioConverterInputDataProc) Deprecated. Use [`AudioConverterFillComplexBuffer(_:_:_:_:_:_:)`](/documentation/AudioToolbox/AudioConverterFillComplexBuffer(_:_:_:_:_:_:)) instead. ### Data Types [`AudioConverterPrimeInfo`](/documentation/AudioToolbox/AudioConverterPrimeInfo) Specifies priming information for an audio converter. [`AudioConverterRef`](/documentation/AudioToolbox/AudioConverterRef) A reference to an audio converter object. [`AudioConverterPropertyID`](/documentation/AudioToolbox/AudioConverterPropertyID) An audio converter property identifier. ### Constants [Audio Converter Properties](/documentation/AudioToolbox/1559928-audio-converter-properties) Audio converter properties, used with the [`AudioConverterGetPropertyInfo(_:_:_:_:)`](/documentation/AudioToolbox/AudioConverterGetPropertyInfo(_:_:_:_:)), [`AudioConverterGetProperty(_:_:_:_:)`](/documentation/AudioToolbox/AudioConverterGetProperty(_:_:_:_:)), and [`AudioConverterSetProperty(_:_:_:_:)`](/documentation/AudioToolbox/AudioConverterSetProperty(_:_:_:_:)) functions. [Converter Priming Constants](/documentation/AudioToolbox/1559927-converter-priming-constants) Constants used with the [`kAudioConverterPrimeMethod`](/documentation/AudioToolbox/kAudioConverterPrimeMethod) property. [Sample Rate Conversion Quality Identifiers](/documentation/AudioToolbox/1559924-sample-rate-conversion-quality-i) Specifiers for sample rate conversion quality, used for the [`kAudioConverterSampleRateConverterQuality`](/documentation/AudioToolbox/kAudioConverterSampleRateConverterQuality) property. [Sample Rate Conversion Complexity Identifiers](/documentation/AudioToolbox/1559923-sample-rate-conversion-complexit) Specifiers for the sample rate conversion algorithm, used for the [`kAudioConverterSampleRateConverterComplexity`](/documentation/AudioToolbox/kAudioConverterSampleRateConverterComplexity) property. ### Enumerations [Converter Audio Unit Properties](/documentation/AudioToolbox/1533972-converter_audio_unit_properties) Properties for the Apple AUConverter audio unit. [Converter Audio Unit Subtypes](/documentation/AudioToolbox/1584145-converter_audio_unit_subtypes) Audio data format converter audio unit subtypes for audio units provided by Apple. [Audio Converter Dithering Algorithms](/documentation/AudioToolbox/1559931-audio-converter-dithering-algori) [Audio Converter Properties (macOS)](/documentation/AudioToolbox/1559925-audio-converter-properties-macos) [Audio Converter Errors](/documentation/AudioToolbox/1559930-audio-converter-errors) ### Result Codes This table lists result codes defined for Audio Converter Services. [`kAudioConverterErr_FormatNotSupported`](/documentation/AudioToolbox/kAudioConverterErr_FormatNotSupported) [`kAudioConverterErr_OperationNotSupported`](/documentation/AudioToolbox/kAudioConverterErr_OperationNotSupported) [`kAudioConverterErr_PropertyNotSupported`](/documentation/AudioToolbox/kAudioConverterErr_PropertyNotSupported) [`kAudioConverterErr_InvalidInputSize`](/documentation/AudioToolbox/kAudioConverterErr_InvalidInputSize) [`kAudioConverterErr_InvalidOutputSize`](/documentation/AudioToolbox/kAudioConverterErr_InvalidOutputSize) The byte size is not an integer multiple of the frame size. [`kAudioConverterErr_UnspecifiedError`](/documentation/AudioToolbox/kAudioConverterErr_UnspecifiedError) [`kAudioConverterErr_BadPropertySizeError`](/documentation/AudioToolbox/kAudioConverterErr_BadPropertySizeError) [`kAudioConverterErr_RequiresPacketDescriptionsError`](/documentation/AudioToolbox/kAudioConverterErr_RequiresPacketDescriptionsError) [`kAudioConverterErr_InputSampleRateOutOfRange`](/documentation/AudioToolbox/kAudioConverterErr_InputSampleRateOutOfRange) [`kAudioConverterErr_OutputSampleRateOutOfRange`](/documentation/AudioToolbox/kAudioConverterErr_OutputSampleRateOutOfRange) [`kAudioConverterErr_HardwareInUse`](/documentation/AudioToolbox/kAudioConverterErr_HardwareInUse) Returned from the [`AudioConverterFillComplexBuffer(_:_:_:_:_:_:)`](/documentation/AudioToolbox/AudioConverterFillComplexBuffer(_:_:_:_:_:_:)) function if the underlying hardware codec has become unavailable, probably due to an audio interruption. [`kAudioConverterErr_NoHardwarePermission`](/documentation/AudioToolbox/kAudioConverterErr_NoHardwarePermission) Returned from the [`AudioConverterNew(_:_:_:)`](/documentation/AudioToolbox/AudioConverterNew(_:_:_:)) function if the new converter would use a hardware codec which the application does not have permission to use. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)