# Extended Audio File Services Read and write compressed files and linear PCM audio files using a simplified interface. ## Discussion Extended Audio File Services provides simplified audio file access, combining features of Audio File Services and Audio Converter Services. It provides a unified interface for reading and writing compressed as well as linear PCM audio files. ## Topics ### Managing Extended Audio File Objects [`ExtAudioFileCreateWithURL(_:_:_:_:_:_:)`](/documentation/AudioToolbox/ExtAudioFileCreateWithURL(_:_:_:_:_:_:)) Creates a new audio file and associates it with a new extended audio file object. [`ExtAudioFileDispose(_:)`](/documentation/AudioToolbox/ExtAudioFileDispose(_:)) Disposes of an extended audio file object and closes the associated file. [`ExtAudioFileOpenURL(_:_:)`](/documentation/AudioToolbox/ExtAudioFileOpenURL(_:_:)) Opens an existing audio file for reading, and associates it with a new extended audio file object. [`ExtAudioFileWrapAudioFileID(_:_:_:)`](/documentation/AudioToolbox/ExtAudioFileWrapAudioFileID(_:_:_:)) Wraps an audio file object in an extended audio file object. ### Configuring Properties for Extended Audio File Objects [`ExtAudioFileGetProperty(_:_:_:_:)`](/documentation/AudioToolbox/ExtAudioFileGetProperty(_:_:_:_:)) Gets a property value from an extended audio file object. [`ExtAudioFileGetPropertyInfo(_:_:_:_:)`](/documentation/AudioToolbox/ExtAudioFileGetPropertyInfo(_:_:_:_:)) Gets information about an extended audio file object property. [`ExtAudioFileSetProperty(_:_:_:_:)`](/documentation/AudioToolbox/ExtAudioFileSetProperty(_:_:_:_:)) Sets a property value for an extended audio file object. ### Reading and Writing Audio Data [`ExtAudioFileRead(_:_:_:)`](/documentation/AudioToolbox/ExtAudioFileRead(_:_:_:)) Performs a synchronous, sequential read operation on an audio file. [`ExtAudioFileSeek(_:_:)`](/documentation/AudioToolbox/ExtAudioFileSeek(_:_:)) Seeks to a specified frame in a file. [`ExtAudioFileTell(_:_:)`](/documentation/AudioToolbox/ExtAudioFileTell(_:_:)) Gets an audio file’s read/write position. [`ExtAudioFileWrite(_:_:_:)`](/documentation/AudioToolbox/ExtAudioFileWrite(_:_:_:)) Performs a synchronous, sequential write operation on an audio file. [`ExtAudioFileWriteAsync(_:_:_:)`](/documentation/AudioToolbox/ExtAudioFileWriteAsync(_:_:_:)) Perform an asynchronous, sequential write operation on an audio file. ### Deprecated Functions [`ExtAudioFileCreateNew`](/documentation/AudioToolbox/ExtAudioFileCreateNew) Deprecated. Use the [`ExtAudioFileCreateWithURL(_:_:_:_:_:_:)`](/documentation/AudioToolbox/ExtAudioFileCreateWithURL(_:_:_:_:_:_:)) function instead. [`ExtAudioFileOpen`](/documentation/AudioToolbox/ExtAudioFileOpen) Deprecated. Use the [`ExtAudioFileOpenURL(_:_:)`](/documentation/AudioToolbox/ExtAudioFileOpenURL(_:_:)) function instead. ### Data Types [`ExtAudioFilePacketTableInfoOverride`](/documentation/AudioToolbox/ExtAudioFilePacketTableInfoOverride) [`ExtAudioFileRef`](/documentation/AudioToolbox/ExtAudioFileRef) An opaque structure representing an extended audio file object. [`ExtAudioFilePropertyID`](/documentation/AudioToolbox/ExtAudioFilePropertyID) An audio file object property identifier. ### Constants [Extended Audio FIle Errors](/documentation/AudioToolbox/1486883-extended-audio-file-errors) [Codec Unavailable Errors](/documentation/AudioToolbox/1623673-codec-unavailable-errors) [Property Identifiers for Extended Audio File Objects](/documentation/AudioToolbox/1486859-property-identifiers-for-extende) [Extended Audio File Packet Overrides](/documentation/AudioToolbox/3547074-extended-audio-file-packet-overr) ### Result Codes This table lists result codes defined for Extended Audio File Services. [`kExtAudioFileError_CodecUnavailableInputConsumed`](/documentation/AudioToolbox/kExtAudioFileError_CodecUnavailableInputConsumed) The [`ExtAudioFileWrite(_:_:_:)`](/documentation/AudioToolbox/ExtAudioFileWrite(_:_:_:)) function was interrupted and the last buffer that you provided was successfully written to disk. [`kExtAudioFileError_CodecUnavailableInputNotConsumed`](/documentation/AudioToolbox/kExtAudioFileError_CodecUnavailableInputNotConsumed) The [`ExtAudioFileWrite(_:_:_:)`](/documentation/AudioToolbox/ExtAudioFileWrite(_:_:_:)) function was interrupted and the last buffer that you provided was *not* successfully written to disk. [`kExtAudioFileError_InvalidProperty`](/documentation/AudioToolbox/kExtAudioFileError_InvalidProperty) [`kExtAudioFileError_InvalidPropertySize`](/documentation/AudioToolbox/kExtAudioFileError_InvalidPropertySize) [`kExtAudioFileError_NonPCMClientFormat`](/documentation/AudioToolbox/kExtAudioFileError_NonPCMClientFormat) [`kExtAudioFileError_InvalidChannelMap`](/documentation/AudioToolbox/kExtAudioFileError_InvalidChannelMap) The number of channels does not match the specified format. [`kExtAudioFileError_InvalidOperationOrder`](/documentation/AudioToolbox/kExtAudioFileError_InvalidOperationOrder) [`kExtAudioFileError_InvalidDataFormat`](/documentation/AudioToolbox/kExtAudioFileError_InvalidDataFormat) [`kExtAudioFileError_MaxPacketSizeUnknown`](/documentation/AudioToolbox/kExtAudioFileError_MaxPacketSizeUnknown) [`kExtAudioFileError_InvalidSeek`](/documentation/AudioToolbox/kExtAudioFileError_InvalidSeek) An attempt to write, or an offset, is out of bounds. [`kExtAudioFileError_AsyncWriteTooLarge`](/documentation/AudioToolbox/kExtAudioFileError_AsyncWriteTooLarge) [`kExtAudioFileError_AsyncWriteBufferOverflow`](/documentation/AudioToolbox/kExtAudioFileError_AsyncWriteBufferOverflow) An asynchronous write operation could not be completed in time. --- 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)