Core Audio Data Types

This document describes data types and constants used throughout Core Audio, as well as some convenience functions for working with these types and constants.

Overview

If you are unfamiliar with the specialized terminology used when manipulating audio data, refer to Core Audio Glossary.

Symbols

Data Types

Audio​Buffer

Holds and describes a buffer of audio data.

Audio​Buffer​List

Holds a variable-length array of Audio​Buffer structures.

Audio​Channel​Description

Describes an audio data channel.

Audio​Channel​Label

Identifies how an audio data channel is to be used.

Audio​Channel​Layout

Specifies a channel layout in a file or in hardware.

Audio​Channel​Layout​Tag

Identifies a previously-defined channel layout.

Audio​Class​Description

Describes an installed codec.

Audio​Class​IDAudio​Device​IDAudio​Device​IOBlockAudio​Device​IOProcAudio​Device​IOProc​IDAudio​Device​Property​IDAudio​Device​Property​Listener​ProcAudio​Format​FlagsAudio​Format​IDAudio​Hardware​Property​IDAudio​Hardware​Property​Listener​ProcAudio​Object​IDAudio​Object​Property​ElementAudio​Object​Property​Listener​BlockAudio​Object​Property​Listener​ProcAudio​Object​Property​ScopeAudio​Object​Property​Selector
Audio​Sample​Type

The canonical audio data sample type for input and output.

Deprecated
Audio​Stream​Basic​Description

An audio data format specification for a stream of audio.

Audio​Stream​ID
Audio​Stream​Packet​Description

Describes one packet in a buffer of audio data where the sizes of the packets differ or where there is non-audio data between audio packets.

Audio​Stream​Property​Listener​Proc
Audio​Time​Stamp

Holds multiple representations of a time stamp.

Audio​Unit​Sample​Type

The canonical audio data sample type for audio processing.

Deprecated
Audio​Value​Range

Holds a pair of numbers that represent a continuous range of values.

Audio​Value​Translation

Holds buffers used in translation operations.

SMPTETime

Specifies a time stamp as one of the SMPTE time types.

Constants

Sample Type Constants

Constants used for specifying audio format flags

k​Audio​Stream​Any​Rate

Indicates that an audio format can use any sample rate.

Audio Data Format Identifiers

Identifiers for audio data formats, used in the Audio​Stream​Basic​Description structure.

Audio​Stream​Basic​Description Flags

Standard flags for use in the m​Format​Flags field of the Audio​Stream​Basic​Description structure.

Audio​Stream​Basic​Description Flag Combinations Constants

Commonly used combinations of data format flags for the Audio​Stream​Basic​Description structure.

MPEG-4 Audio Object Type Constants

Used in the m​Format​Flags field of an Audio​Stream​Basic​Description structure that describes an MPEG-4 audio stream to specify the type of MPEG-4 audio data.

SMPTE Timecode Type Constants

SMPTE timecode types, used in the SMPTETime structure.

SMPTE State Flags

Flags that describe a SMPTE time state.

Audio Time Stamp Flags

These flags indicate the valid fields in an Audio​Time​Stamp structure.

Audio Time Stamp Flag Combination Constant

A commonly used combination of audio time stamp flags.

Audio Channel Label Constants

Channel labels for use in the m​Channel​Label field of an Audio​Channel​Description structure.

Channel Bitmap Constants

Channel bits for use in the m​Channel​Bitmap field of an Audio​Channel​Layout structure.

Channel Coordinate Flags

Used in the m​Channel​Flags field of an Audio​Channel​Description structure.

Audio​Channel​Coordinate​Index

Indexes the fields of the m​Coordinates array in an Audio​Channel​Description structure.

Audio Channel Layout Tags

Identifiers for audio channel layouts. These identifiers specify the channels included in a layout but do not specify a particular ordering of those channels. Used in the m​Channel​Layout​Tag field of an Audio​Channel​Layout structure.

Result Codes

This table lists result codes returned from the various C-based audio frameworks.

var k​Audio_Unimplemented​Error:​ OSStatus

An unimplemented system function was called.

var k​Audio_Param​Error:​ OSStatus

An error in the parameter list of the function.

var k​Audio_Mem​Full​Error:​ OSStatus

Not enough room in the heap zone.