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CoreAudio Framework Reference Core Audio Data Types Reference

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Core Audio Data Types Reference

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Import Statement


Swift

import CoreAudio

Objective-C

@import CoreAudio;

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

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

Functions

  • A macro for checking if an AudioFormatBasicDescription structure indicates native endian linear PCM data.

    Declaration

    Objective-C

    #define TestAudioFormatNativeEndian (f) ( (f.mFormatID == kAudioFormatLinearPCM) && ((f.mFormatFlags & kAudioFormatFlagIsBigEndian) == kAudioFormatFlagsNativeEndian) )

    Parameters

    f

    The AudioFormatBasicDescription structure you want to examine.

    Return Value

    True if the data is linear PCM and is native endian.

    Import Statement

    Objective-C

    @import CoreAudio;

    Availability

    Available in iOS 2.0 and later

  • IsAudioFormatNativeEndian IsAudioFormatNativeEndian Available in iOS 2.0 through iOS 7.1

    A C++ inline function for checking if an AudioFormatBasicDescription structure indicates native-endian linear PCM data.

    Declaration

    Objective-C

    bool IsAudioFormatNativeEndian ( const AudioStreamBasicDescription &f );

    Parameters

    f

    The AudioFormatBasicDescription structure you want to examine.

    Return Value

    A Boolean value indicating whether the AudioFormatBasicDescription structure specifies native endian linear PCM data, true if the data is linear PCM and is native endian.

    Import Statement

    Objective-C

    @import CoreAudio;

    Availability

    Available in iOS 2.0 through iOS 7.1

  • A macro to get the number of channels from an audio channel layout tag (AudioChannelLayoutTag data type).

    Declaration

    Objective-C

    #define AudioChannelLayoutTag_GetNumberOfChannels(layoutTag) ((UInt32)((layoutTag) & 0x0000FFFF))

    Parameters

    layoutTag

    The audio channel layout tag to examine.

    Return Value

    The number of channels the tag indicates.

    Discussion

    The low 16 bits of an audio channel layout tag gives the number of channels, unless the layout tag is kAudioChannelLayoutTag_UseChannelDescriptions or kAudioChannelLayoutTag_UseChannelBitmap, which specify other ways of defining the layout.

    Import Statement

    Objective-C

    @import CoreAudio;

    Availability

    Available in iOS 2.0 and later

  • CalculateLPCMFlags CalculateLPCMFlags Available in iOS 2.0 through iOS 7.1

    A C++ inline function for calculating the value for the audio stream basic description mFormatFlags field for linear PCM data.

    Declaration

    Objective-C

    UInt32 CalculateLPCMFlags ( UInt32 inValidBitsPerChannel, UInt32 inTotalBitsPerChannel, bool inIsFloat, bool inIsBigEndian, bool inIsNonInterleaved );

    Parameters

    inValidBitsPerChannel

    The number of valid bits in each sample.

    inTotalBitsPerChannel

    The total number of bits in each sample.

    inIsFloat

    Use true if the samples are represented with floating point numbers.

    inIsBigEndian

    Use true if the samples are big endian.

    inIsNonInterleaved

    Use true if the samples are noninterleaved.

    Return Value

    A UInt32 value containing the calculated format flags.

    Discussion

    This function does not support specifying sample formats that are either unsigned integer or low-aligned.

    Import Statement

    Objective-C

    @import CoreAudio;

    Availability

    Available in iOS 2.0 through iOS 7.1

  • FillOutASBDForLPCM FillOutASBDForLPCM Available in iOS 2.0 through iOS 7.1

    A C++ inline function for filling out an AudioStreamBasicDescription to describe linear PCM data.

    Declaration

    Objective-C

    void FillOutASBDForLPCM ( AudioStreamBasicDescription &outASBD, Float64 inSampleRate, UInt32 inChannelsPerFrame, UInt32 inValidBitsPerChannel, UInt32 inTotalBitsPerChannel, bool inIsFloat, bool inIsBigEndian, bool inIsNonInterleaved );

    Parameters

    outASBD

    On output, a filled-out AudioStreamBasicDescription structure.

    inSampleRate

    The number of sample frames per second of the data in the stream.

    inChannelsPerFrame

    The number of channels in each frame of data.

    inValidBitsPerChannel

    The number of valid bits in each sample.

    inTotalBitsPerChannel

    The total number of bits in each sample.

    inIsFloat

    Use true if the samples are represented as floating-point numbers.

    inIsBigEndian

    Use true if the samples are big endian.

    inIsNonInterleaved

    Use true if the samples are noninterleaved.

    Discussion

    This function does not support specifying sample formats that are either unsigned integer or low-aligned.

    Import Statement

    Objective-C

    @import CoreAudio;

    Availability

    Available in iOS 2.0 through iOS 7.1

  • A C++ inline function for filling out an AudioTimeStamp structure with a host time.

    Declaration

    Objective-C

    void FillOutAudioTimeStampWithHostTime ( AudioTimeStamp &outATS, UInt64 inHostTime );

    Parameters

    outATS

    On output, a filled-out AudioTimeStamp structure.

    inHostTime

    The host time to assign to the audio timestamp.

    Import Statement

    Objective-C

    @import CoreAudio;

    Availability

    Available in iOS 2.0 through iOS 7.1

  • A C++ inline function for filling out an AudioTimeStamp structure with a sample time.

    Declaration

    Objective-C

    void FillOutAudioTimeStampWithSampleTime ( AudioTimeStamp &outATS, Float64 inSampleTime );

    Parameters

    outATS

    On output, a filled-out AudioTimeStamp structure.

    inSampleTime

    The sample time to assign to the audio timestamp.

    Import Statement

    Objective-C

    @import CoreAudio;

    Availability

    Available in iOS 2.0 through iOS 7.1

  • A C++ inline function for filling out an AudioTimeStamp structure with a sample time and a host time.

    Declaration

    Objective-C

    void FillOutAudioTimeStampWithSampleAndHostTime ( AudioTimeStamp &outATS, Float64 inSampleTime, UInt64 inHostTime );

    Parameters

    outATS

    On output, a filled-out AudioTimeStamp structure.

    inSampleTime

    The sample time to assign to the audio timestamp.

    inHostTime

    The host time to assign to the audio timestamp.

    Import Statement

    Objective-C

    @import CoreAudio;

    Availability

    Available in iOS 2.0 through iOS 7.1

Data Types

  • Holds and describes a buffer of audio data.

    Declaration

    Swift

    struct AudioBuffer { var mNumberChannels: UInt32 var mDataByteSize: UInt32 var mData: UnsafeMutablePointer<Void> init() init(mNumberChannels mNumberChannels: UInt32, mDataByteSize mDataByteSize: UInt32, mData mData: UnsafeMutablePointer<Void>) } extension AudioBuffer { init<T>(_ typedBuffer: UnsafeMutableBufferPointer<T>, numberOfChannels numberOfChannels: Int) } extension AudioBuffer { init<T>(_ typedBuffer: UnsafeMutableBufferPointer<T>, numberOfChannels numberOfChannels: Int) }

    Objective-C

    struct AudioBuffer { UInt32 mNumberChannels; UInt32 mDataByteSize; void *mData; }; typedef struct AudioBuffer AudioBuffer;

    Fields

    mNumberChannels

    The number of interleaved channels in the buffer. If the number is 1, the buffer is noninterleaved.

    mDataByteSize

    The number of bytes in the buffer pointed at by the mData field.

    mData

    A pointer to a buffer of audio data.

    Discussion

    An AudioBuffer structure holds a single buffer of audio data in its mData field. The buffer can represent two different sorts of audio:

    • A single, monophonic, noninterleaved channel of audio

    • Interleaved audio with any number of channels—as designated by the mNumberChannels field

    Noninterleaved formats are used primarily by audio units and audio converters.

    Availability

    Available in iOS 2.0 and later

  • Holds a variable-length array of AudioBuffer structures.

    Declaration

    Swift

    struct AudioBufferList { var mNumberBuffers: UInt32 var mBuffers: (AudioBuffer) init() init(mNumberBuffers mNumberBuffers: UInt32, mBuffers mBuffers: (AudioBuffer)) } extension AudioBufferList { static func sizeInBytes(maximumBuffers maximumBuffers: Int) -> Int static func allocate(maximumBuffers maximumBuffers: Int) -> UnsafeMutableAudioBufferListPointer } extension AudioBufferList { static func sizeInBytes(maximumBuffers maximumBuffers: Int) -> Int static func allocate(maximumBuffers maximumBuffers: Int) -> UnsafeMutableAudioBufferListPointer }

    Objective-C

    struct AudioBufferList { UInt32 mNumberBuffers; AudioBuffer mBuffers[1]; }; typedef struct AudioBufferList AudioBufferList;

    Fields

    mNumberBuffers

    The number of AudioBuffer structures in the mBuffers array.

    mBuffers

    A variable length array of AudioBuffer structures.

    Discussion

    The AudioBufferList structure provides a mechanism for encapsulating one or more buffers of audio data. It is used by functions in various Core Audio APIs, as described in Audio Converter Services Reference, Audio Unit Component Services Reference, and Extended Audio File Services Reference.

    Availability

    Available in iOS 2.0 and later

  • Describes an audio data channel.

    Declaration

    Swift

    struct AudioChannelDescription { var mChannelLabel: AudioChannelLabel var mChannelFlags: UInt32 var mCoordinates: (Float32, Float32, Float32) init() init(mChannelLabel mChannelLabel: AudioChannelLabel, mChannelFlags mChannelFlags: UInt32, mCoordinates mCoordinates: (Float32, Float32, Float32)) }

    Objective-C

    struct AudioChannelDescription { AudioChannelLabel mChannelLabel; UInt32 mChannelFlags; Float32 mCoordinates[3]; }; typedef struct AudioChannelDescription AudioChannelDescription;

    Fields

    mChannelLabel

    The AudioChannelLabel structure that describes the channel.

    mChannelFlags

    Flags that control the interpretation of mCoordinates. See “Channel Coordinate Flags” for possible values.

    mCoordinates

    An ordered triple that specifies a precise speaker location. See “Channel Coordinate Index Constants” for the interpretation of the items in the array.

    Availability

    Available in iOS 2.0 and later

  • Identifies how an audio data channel is to be used.

    Declaration

    Swift

    typealias AudioChannelLabel = UInt32

    Objective-C

    typedef UInt32 AudioChannelLabel;

    Discussion

    This data type is used for the mChannelLabel field of the AudioChannelDescription structure. See “Audio Channel Label Constants” for possible values.

    Import Statement

    Objective-C

    @import CoreAudio;

    Swift

    import CoreAudio

    Availability

    Available in iOS 2.0 and later

  • Specifies a channel layout in a file or in hardware.

    Declaration

    Swift

    struct AudioChannelLayout { var mChannelLayoutTag: AudioChannelLayoutTag var mChannelBitmap: UInt32 var mNumberChannelDescriptions: UInt32 var mChannelDescriptions: (AudioChannelDescription) init() init(mChannelLayoutTag mChannelLayoutTag: AudioChannelLayoutTag, mChannelBitmap mChannelBitmap: UInt32, mNumberChannelDescriptions mNumberChannelDescriptions: UInt32, mChannelDescriptions mChannelDescriptions: (AudioChannelDescription)) }

    Objective-C

    struct AudioChannelLayout { AudioChannelLayoutTag mChannelLayoutTag; UInt32 mChannelBitmap; UInt32 mNumberChannelDescriptions; AudioChannelDescription mChannelDescriptions[1]; }; typedef struct AudioChannelLayout AudioChannelLayout;

    Fields

    mChannelLayoutTag

    The AudioChannelLayoutTag value that indicates the layout. See “Audio Channel Layout Tags” for possible values.

    mChannelBitmap

    If mChannelLayoutTag is set to kAudioChannelLayoutTag_UseChannelBitmap, this field is the channel-use bitmap.

    mNumberChannelDescriptions

    The number of items in the mChannelDescriptions array.

    mChannelDescriptions

    A variable length array of mNumberChannelDescription elements that describes a layout. If the mChannelLayoutTag field is set to kAudioChannelLayoutTag_UseChannelDescriptions, use this field to describe the layout.

    Availability

    Available in iOS 2.0 and later

  • Identifies a previously-defined channel layout.

    Declaration

    Swift

    typealias AudioChannelLayoutTag = UInt32

    Objective-C

    typedef UInt32 AudioChannelLayoutTag;

    Discussion

    This data type is used for the mChannelLayoutTag field of the AudioChannelLayout structure. See “Audio Channel Layout Tags” for possible values.

    Import Statement

    Objective-C

    @import CoreAudio;

    Swift

    import CoreAudio

    Availability

    Available in iOS 2.0 and later

  • Describes an installed codec.

    Declaration

    Swift

    struct AudioClassDescription { var mType: OSType var mSubType: OSType var mManufacturer: OSType init() init(mType mType: OSType, mSubType mSubType: OSType, mManufacturer mManufacturer: OSType) }

    Objective-C

    struct AudioClassDescription { OSType mType; OSType mSubType; OSType mManufacturer; }; typedef struct AudioClassDescription AudioClassDescription;

    Fields

    mType

    The four character code for the codec type. Defined by the codec manufacturer.

    mSubType

    The four character code for the codec subtype. Defined by the codec manufacturer.

    mManufacturer

    The four character code for the codec manufacturer. This must be a unique code registered with Apple.

    Availability

    Available in iOS 2.0 and later

  • The canonical audio data sample type for input and output.

    Declaration

    Objective-C

    typedef SInt16 AudioSampleType;

    Discussion

    The canonical audio sample type for input and output in iPhone OS is linear PCM with 16-bit integer samples.

    Import Statement

    Objective-C

    @import CoreAudio;

    Availability

    Available in iOS 2.0 and later

    Deprecated in iOS 8.0

  • The canonical audio data sample type for audio processing.

    Declaration

    Objective-C

    typedef SInt32 AudioUnitSampleType; #define kAudioUnitSampleFractionBits 24

    Discussion

    The canonical audio sample type for audio units and other audio processing in iPhone OS is noninterleaved linear PCM with 8.24-bit fixed-point samples.

    Import Statement

    Objective-C

    @import CoreAudio;

    Availability

    Available in iOS 2.0 and later

    Deprecated in iOS 8.0

  • An audio data format specification for a stream of audio.

    Declaration

    Swift

    struct AudioStreamBasicDescription { var mSampleRate: Float64 var mFormatID: AudioFormatID var mFormatFlags: AudioFormatFlags var mBytesPerPacket: UInt32 var mFramesPerPacket: UInt32 var mBytesPerFrame: UInt32 var mChannelsPerFrame: UInt32 var mBitsPerChannel: UInt32 var mReserved: UInt32 init() init(mSampleRate mSampleRate: Float64, mFormatID mFormatID: AudioFormatID, mFormatFlags mFormatFlags: AudioFormatFlags, mBytesPerPacket mBytesPerPacket: UInt32, mFramesPerPacket mFramesPerPacket: UInt32, mBytesPerFrame mBytesPerFrame: UInt32, mChannelsPerFrame mChannelsPerFrame: UInt32, mBitsPerChannel mBitsPerChannel: UInt32, mReserved mReserved: UInt32) }

    Objective-C

    struct AudioStreamBasicDescription { Float64 mSampleRate; UInt32 mFormatID; UInt32 mFormatFlags; UInt32 mBytesPerPacket; UInt32 mFramesPerPacket; UInt32 mBytesPerFrame; UInt32 mChannelsPerFrame; UInt32 mBitsPerChannel; UInt32 mReserved; }; typedef struct AudioStreamBasicDescription AudioStreamBasicDescription;

    Fields

    mSampleRate

    The number of frames per second of the data in the stream, when the stream is played at normal speed. For compressed formats, this field indicates the number of frames per second of equivalent decompressed data.

    The mSampleRate field must be nonzero, except when this structure is used in a listing of supported formats (see “kAudioStreamAnyRate”).

    mFormatID

    An identifier specifying the general audio data format in the stream. See “Audio Data Format Identifiers”. This value must be nonzero.

    mFormatFlags

    Format-specific flags to specify details of the format. Set to 0 to indicate no format flags. See “Audio Data Format Identifiers” for the flags that apply to each format.

    mBytesPerPacket

    The number of bytes in a packet of audio data. To indicate variable packet size, set this field to 0. For a format that uses variable packet size, specify the size of each packet using an AudioStreamPacketDescription structure.

    mFramesPerPacket

    The number of frames in a packet of audio data. For uncompressed audio, the value is 1. For variable bit-rate formats, the value is a larger fixed number, such as 1024 for AAC. For formats with a variable number of frames per packet, such as Ogg Vorbis, set this field to 0.

    mBytesPerFrame

    The number of bytes from the start of one frame to the start of the next frame in an audio buffer. Set this field to 0 for compressed formats.

    For an audio buffer containing interleaved data for n channels, with each sample of type AudioSampleType, calculate the value for this field as follows:

    • mBytesPerFrame = n * sizeof (AudioSampleType);

    For an audio buffer containing noninterleaved (monophonic) data, also using AudioSampleType samples, calculate the value for this field as follows:

    • mBytesPerFrame = sizeof (AudioSampleType);
    mChannelsPerFrame

    The number of channels in each frame of audio data. This value must be nonzero.

    mBitsPerChannel

    The number of bits for one audio sample. For example, for linear PCM audio using the kAudioFormatFlagsCanonical format flags, calculate the value for this field as follows:

    • mBitsPerChannel = 8 * sizeof (AudioSampleType);

    Set this field to 0 for compressed formats.

    mReserved

    Pads the structure out to force an even 8-byte alignment. Must be set to 0.

    Discussion

    You can configure an audio stream basic description (ASBD) to specify a linear PCM format or a constant bit rate (CBR) format that has channels of equal size. For variable bit rate (VBR) audio, and for CBR audio where the channels have unequal sizes, each packet must additionally be described by an AudioStreamPacketDescription structure.

    A field value of 0 indicates that the value is either unknown or not applicable to the format.

    Always initialize the fields of a new audio stream basic description structure to zero, as shown here:

    • AudioStreamBasicDescription myAudioDataFormat = {0};

    To determine the duration represented by one packet, use the mSampleRate field with the mFramesPerPacket field, as follows:

    • duration = (1 / mSampleRate) * mFramesPerPacket

    In Core Audio, the following definitions apply:

    • An audio stream is a continuous series of data that represents a sound, such as a song.

    • A channel is a discrete track of monophonic audio. A monophonic stream has one channel; a stereo stream has two channels.

    • A sample is single numerical value for a single audio channel in an audio stream.

    • A frame is a collection of time-coincident samples. For instance, a linear PCM stereo sound file has two samples per frame, one for the left channel and one for the right channel.

    • A packet is a collection of one or more contiguous frames. A packet defines the smallest meaningful set of frames for a given audio data format, and is the smallest data unit for which time can be measured. In linear PCM audio, a packet holds a single frame. In compressed formats, it typically holds more; in some formats, the number of frames per packet varies.

    • The sample rate for a stream is the number of frames per second of uncompressed (or, for compressed formats, the equivalent in decompressed) audio.

    Availability

    Available in iOS 2.0 and later

  • 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.

    Declaration

    Swift

    struct AudioStreamPacketDescription { var mStartOffset: Int64 var mVariableFramesInPacket: UInt32 var mDataByteSize: UInt32 init() init(mStartOffset mStartOffset: Int64, mVariableFramesInPacket mVariableFramesInPacket: UInt32, mDataByteSize mDataByteSize: UInt32) }

    Objective-C

    struct AudioStreamPacketDescription { SInt64 mStartOffset; UInt32 mVariableFramesInPacket; UInt32 mDataByteSize; }; typedef struct AudioStreamPacketDescription AudioStreamPacketDescription;

    Fields

    mStartOffset

    The number of bytes from the start of the buffer to the beginning of the packet. For example, if the data buffer contains 5 bytes of data, with one byte per packet, then mStartOffset for the last packet is 4 (that is, there are 4 bytes in the buffer before the start of the last packet.

    mVariableFramesInPacket

    The number of sample frames of data in the packet. For formats with a constant number of frames per packet, this field is set to 0.

    mDataByteSize

    The number of bytes in the packet.

    Discussion

    For data formats where the packet size is not constant, such as variable bit rate data and data where the channels have unequal sizes, this structure is used to supplement the information in the AudioStreamBasicDescription structure.

    Availability

    Available in iOS 2.0 and later

  • Holds multiple representations of a time stamp.

    Declaration

    Swift

    struct AudioTimeStamp { var mSampleTime: Float64 var mHostTime: UInt64 var mRateScalar: Float64 var mWordClockTime: UInt64 var mSMPTETime: SMPTETime var mFlags: UInt32 var mReserved: UInt32 init() init(mSampleTime mSampleTime: Float64, mHostTime mHostTime: UInt64, mRateScalar mRateScalar: Float64, mWordClockTime mWordClockTime: UInt64, mSMPTETime mSMPTETime: SMPTETime, mFlags mFlags: UInt32, mReserved mReserved: UInt32) }

    Objective-C

    struct AudioTimeStamp { Float64 mSampleTime; UInt64 mHostTime; Float64 mRateScalar; UInt64 mWordClockTime; SMPTETime mSMPTETime; UInt32 mFlags; UInt32 mReserved; }; typedef struct AudioTimeStamp AudioTimeStamp;

    Fields

    mSampleTime

    The absolute sample frame time.

    mHostTime

    The host machine's time base (see CoreAudio/HostTime.h).

    mRateScalar

    The ratio of actual host ticks per sample frame to the nominal host ticks per sample frame.

    mWordClockTime

    The word clock time.

    mSMPTETime

    The SMPTE time (see SMPTETime).

    mFlags

    A set of flags indicating which representations of the time are valid; see “Audio Time Stamp Flags” and “Audio Time Stamp Flag Combination Constant”.

    mReserved

    Pads the structure out to force an even 8-byte alignment.

    Availability

    Available in iOS 2.0 and later

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

    Declaration

    Swift

    struct AudioValueRange { var mMinimum: Float64 var mMaximum: Float64 init() init(mMinimum mMinimum: Float64, mMaximum mMaximum: Float64) }

    Objective-C

    struct AudioValueRange { Float64 mMinimum; Float64 mMaximum; }; typedef struct AudioValueRange AudioValueRange;

    Fields

    mMinimum

    The minimum value.

    mMaximum

    The maximum value.

    Availability

    Available in iOS 2.0 and later

  • Holds buffers used in translation operations.

    Declaration

    Swift

    struct AudioValueTranslation { var mInputData: UnsafeMutablePointer<Void> var mInputDataSize: UInt32 var mOutputData: UnsafeMutablePointer<Void> var mOutputDataSize: UInt32 init() init(mInputData mInputData: UnsafeMutablePointer<Void>, mInputDataSize mInputDataSize: UInt32, mOutputData mOutputData: UnsafeMutablePointer<Void>, mOutputDataSize mOutputDataSize: UInt32) }

    Objective-C

    struct AudioValueTranslation { void* mInputData; UInt32 mInputDataSize; void* mOutputData; UInt32 mOutputDataSize; }; typedef struct AudioValueTranslation AudioValueTranslation;

    Fields

    mInputData

    The buffer containing the data to be translated.

    mInputDataSize

    The number of bytes in the buffer pointed at by mInputData.

    mOutputData

    The buffer to hold the result of the translation.

    mOutputDataSize

    The number of bytes in the buffer pointed at by mOutputData.

    Availability

    Available in iOS 2.0 and later

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

    Declaration

    Swift

    struct SMPTETime { var mSubframes: Int16 var mSubframeDivisor: Int16 var mCounter: UInt32 var mType: UInt32 var mFlags: UInt32 var mHours: Int16 var mMinutes: Int16 var mSeconds: Int16 var mFrames: Int16 init() init(mSubframes mSubframes: Int16, mSubframeDivisor mSubframeDivisor: Int16, mCounter mCounter: UInt32, mType mType: UInt32, mFlags mFlags: UInt32, mHours mHours: Int16, mMinutes mMinutes: Int16, mSeconds mSeconds: Int16, mFrames mFrames: Int16) }

    Objective-C

    struct SMPTETime { SInt16 mSubframes; SInt16 mSubframeDivisor; UInt32 mCounter; UInt32 mType; UInt32 mFlags; SInt16 mHours; SInt16 mMinutes; SInt16 mSeconds; SInt16 mFrames; }; typedef struct SMPTETime SMPTETime;

    Fields

    mSubframes

    A subframe offset to the HH:MM:SS:FF time. You can use this field to position a time marker somewhere within the time span represented by a video frame, if necessary.

    mSubframeDivisor

    The number of subframes per video frame (typically 80).

    mCounter

    The total number of messages received. It takes 8 messages to carry a full SMPTE time code.

    mType

    A SMPTE time type constant indicating the kind of SMPTE time used (see “SMPTE Timecode Type Constants”).

    mFlags

    A set of flags that indicate the SMPTE state (see “SMPTE State Flags”).

    mHours

    The value of the hours portion of the SMPTE time.

    mMinutes

    The value of the minutes portion of the SMPTE time.

    mSeconds

    The value of the seconds portion of the SMPTE time.

    mFrames

    The value of the frames portion of the SMPTE time.

    Discussion

    SMPTE (Society of Motion Picture and Television Engineers, pronounced “SIMPtee”) times are used to correlate a point in an audio stream with an external event. For example, a SMPTE time can be used to correlate a sound in an audio file with a video frame in a movie file.

    Note that the frames referred to by this structure are video frames, where a video frame is a single complete image. (Compare with the definition of audio frames in the discussion for AudioStreamBasicDescription.)

    A complete SMPTE time description takes 80 bits, including 32 user bits that contain vendor-specific information. The actual time-code portion of the SMPTE time description is normally sent in several messages, each message containing a portion of the time code. (The user bits are sent in a separate message.) Typically, the SMPTE time description is divided up into 8 1-byte messages, with the first nibble of each message specifying which portion of the time code is contained in the message and the second nibble containing the time information. Four such messages are normally sent with each video frame.

    Video data contains somewhere from 24 to 60 frames per second (as specified by the SMPTE time type—see “SMPTE Timecode Type Constants”) and each video frame has an associated SMPTE time. SMPTE time is based on a 24-hour clock. Each frame’s SMPTE time consists of an hour, minute, and second value, plus the number of the frame within the second. Because audio data is sampled at a much higher rate (MP3 data is sampled at over 100,000 bits per second, for example), it is frequently desirable to correlate the audio data with a time within the persistence period of a single video frame. For this reason, the time period during which a single video frame is displayed is subdivided into subframes (typically 80 or 100 subframes per frame, as specified by the mSubFrameDivisor field). The mSubFrames field specifies the number of subframes into the video frame represented by this time structure.

    Availability

    Available in iOS 2.0 and later

Constants

  • Constants used for specifying audio format flags

    Declaration

    Swift

    var kAudioUnitSampleFractionBits: Int32 { get }

    Objective-C

    #define kAudioUnitSampleFractionBits 24

    Constants

    • kAudioUnitSampleFractionBits

      kAudioUnitSampleFractionBits

      The number of fractional bits in fixed-point samples.

      Available in iOS 2.0 and later

  • Indicates that an audio format can use any sample rate.

    Declaration

    Swift

    var kAudioStreamAnyRate: Int { get }

    Objective-C

    enum { kAudioStreamAnyRate = 0 };

    Constants

    • kAudioStreamAnyRate

      kAudioStreamAnyRate

      This constant can appear only in listings of supported formats. It can never be used as part of the description of an AudioStreamBasicDescription structure that is used for transporting or processing audio.

      Available in iOS 2.0 and later

  • Identifiers for audio data formats, used in the AudioStreamBasicDescription structure.

    Declaration

    Swift

    var kAudioFormatLinearPCM: Int { get } var kAudioFormatAC3: Int { get } var kAudioFormat60958AC3: Int { get } var kAudioFormatAppleIMA4: Int { get } var kAudioFormatMPEG4AAC: Int { get } var kAudioFormatMPEG4CELP: Int { get } var kAudioFormatMPEG4HVXC: Int { get } var kAudioFormatMPEG4TwinVQ: Int { get } var kAudioFormatMACE3: Int { get } var kAudioFormatMACE6: Int { get } var kAudioFormatULaw: Int { get } var kAudioFormatALaw: Int { get } var kAudioFormatQDesign: Int { get } var kAudioFormatQDesign2: Int { get } var kAudioFormatQUALCOMM: Int { get } var kAudioFormatMPEGLayer1: Int { get } var kAudioFormatMPEGLayer2: Int { get } var kAudioFormatMPEGLayer3: Int { get } var kAudioFormatTimeCode: Int { get } var kAudioFormatMIDIStream: Int { get } var kAudioFormatParameterValueStream: Int { get } var kAudioFormatAppleLossless: Int { get } var kAudioFormatMPEG4AAC_HE: Int { get } var kAudioFormatMPEG4AAC_LD: Int { get } var kAudioFormatMPEG4AAC_ELD: Int { get } var kAudioFormatMPEG4AAC_ELD_SBR: Int { get } var kAudioFormatMPEG4AAC_HE_V2: Int { get } var kAudioFormatMPEG4AAC_Spatial: Int { get } var kAudioFormatAMR: Int { get } var kAudioFormatAudible: Int { get } var kAudioFormatiLBC: Int { get } var kAudioFormatDVIIntelIMA: Int { get } var kAudioFormatMicrosoftGSM: Int { get } var kAudioFormatAES3: Int { get }

    Objective-C

    enum { kAudioFormatLinearPCM = 'lpcm', kAudioFormatAC3 = 'ac-3', kAudioFormat60958AC3 = 'cac3', kAudioFormatAppleIMA4 = 'ima4', kAudioFormatMPEG4AAC = 'aac ', kAudioFormatMPEG4CELP = 'celp', kAudioFormatMPEG4HVXC = 'hvxc', kAudioFormatMPEG4TwinVQ = 'twvq', kAudioFormatMACE3 = 'MAC3', kAudioFormatMACE6 = 'MAC6', kAudioFormatULaw = 'ulaw', kAudioFormatALaw = 'alaw', kAudioFormatQDesign = 'QDMC', kAudioFormatQDesign2 = 'QDM2', kAudioFormatQUALCOMM = 'Qclp', kAudioFormatMPEGLayer1 = '.mp1', kAudioFormatMPEGLayer2 = '.mp2', kAudioFormatMPEGLayer3 = '.mp3', kAudioFormatTimeCode = 'time', kAudioFormatMIDIStream = 'midi', kAudioFormatParameterValueStream = 'apvs', kAudioFormatAppleLossless = 'alac' kAudioFormatMPEG4AAC_HE = 'aach', kAudioFormatMPEG4AAC_LD = 'aacl', kAudioFormatMPEG4AAC_ELD = 'aace', kAudioFormatMPEG4AAC_ELD_SBR = 'aacf', kAudioFormatMPEG4AAC_HE_V2 = 'aacp', kAudioFormatMPEG4AAC_Spatial = 'aacs', kAudioFormatAMR = 'samr', kAudioFormatAudible = 'AUDB', kAudioFormatiLBC = 'ilbc', kAudioFormatDVIIntelIMA = 0x6D730011, kAudioFormatMicrosoftGSM = 0x6D730031, kAudioFormatAES3 = 'aes3' };

    Constants

    • kAudioFormatLinearPCM

      kAudioFormatLinearPCM

      A key that specifies linear PCM, a noncompressed audio data format with one frame per packet. Uses the linear PCM format flags in “AudioStreamBasicDescription Flags”.

      Available in iOS 2.0 and later

    • kAudioFormatAC3

      kAudioFormatAC3

      A key that specifies an AC-3 codec. Uses no flags.

      Available in iOS 2.0 and later

    • kAudioFormat60958AC3

      kAudioFormat60958AC3

      A key that specifies an AC-3 codec that provides data packaged for transport over an IEC 60958 compliant digital audio interface. Uses the standard format flags in “AudioStreamBasicDescription Flags”.

      Available in iOS 2.0 and later

    • kAudioFormatAppleIMA4

      kAudioFormatAppleIMA4

      A key that specifies Apple’s implementation of the IMA 4:1 ADPCM codec. Uses no flags.

      Available in iOS 2.0 and later

    • kAudioFormatMPEG4AAC

      kAudioFormatMPEG4AAC

      A key that specifies an MPEG-4 AAC codec. The flags field contains the MPEG-4 audio object type constant listed in “MPEG-4 Audio Object Type Constants” indicating the specific kind of data.

      Available in iOS 2.0 and later

    • kAudioFormatMPEG4CELP

      kAudioFormatMPEG4CELP

      A key that specifies an MPEG-4 CELP codec. The flags field contains the MPEG-4 audio object type constant listed in “MPEG-4 Audio Object Type Constants” indicating the specific kind of data.

      Available in iOS 2.0 and later

    • kAudioFormatMPEG4HVXC

      kAudioFormatMPEG4HVXC

      A key that specifies an MPEG-4 HVXC codec. The flags field contains the MPEG-4 audio object type constant listed in “MPEG-4 Audio Object Type Constants” indicating the specific kind of data.

      Available in iOS 2.0 and later

    • kAudioFormatMPEG4TwinVQ

      kAudioFormatMPEG4TwinVQ

      A key that specifies an MPEG-4 TwinVQ codec. The flags field contains the MPEG-4 audio object type constant listed in “MPEG-4 Audio Object Type Constants” indicating the specific kind of data.

      Available in iOS 2.0 and later

    • kAudioFormatMACE3

      kAudioFormatMACE3

      MACE 3:1. Uses no flags.

      Available in iOS 2.0 and later

    • kAudioFormatMACE6

      kAudioFormatMACE6

      MACE 6:1. Uses no flags.

      Available in iOS 2.0 and later

    • kAudioFormatULaw

      kAudioFormatULaw

      μLaw 2:1. Uses no flags.

      Available in iOS 2.0 and later

    • kAudioFormatALaw

      kAudioFormatALaw

      aLaw 2:1. Uses no flags.

      Available in iOS 2.0 and later

    • kAudioFormatQDesign

      kAudioFormatQDesign

      QDesign music. Uses no flags

      Available in iOS 2.0 and later

    • kAudioFormatQDesign2

      kAudioFormatQDesign2

      QDesign2 music. Uses no flags

      Available in iOS 2.0 and later

    • kAudioFormatQUALCOMM

      kAudioFormatQUALCOMM

      QUALCOMM PureVoice. Uses no flags

      Available in iOS 2.0 and later

    • kAudioFormatMPEGLayer1

      kAudioFormatMPEGLayer1

      MPEG-1/2, Layer 1 audio. Uses no flags

      Available in iOS 2.0 and later

    • kAudioFormatMPEGLayer2

      kAudioFormatMPEGLayer2

      MPEG-1/2, Layer 2 audio. Uses no flags

      Available in iOS 2.0 and later

    • kAudioFormatMPEGLayer3

      kAudioFormatMPEGLayer3

      MPEG-1/2, Layer 3 audio. Uses no flags

      Available in iOS 2.0 and later

    • kAudioFormatTimeCode

      kAudioFormatTimeCode

      A stream of IOAudioTimeStamp structures. Uses the IOAudioTimeStamp flags (see “Audio Time Stamp Flags” and “Audio Time Stamp Flag Combination Constant”).

      Available in iOS 2.0 and later

    • kAudioFormatMIDIStream

      kAudioFormatMIDIStream

      A stream of MIDIPacketList structures where the time stamps in the MIDIPacket structures are sample offsets in the stream. The mSampleRate field in the AudioStreamBasicDescription structure is used to describe how time is passed in this kind of stream and an audio unit that receives or generates this stream can use this sample rate together with the number of frames it is rendering and the sample offsets within the MIDIPacketList to define the time for any MIDI event within this list. Uses no flags.

      Available in iOS 2.0 and later

    • kAudioFormatParameterValueStream

      kAudioFormatParameterValueStream

      A "side-chain" of Float32 data that can be fed or generated by an audio unit and that is used to send a high density of parameter value control information. An audio unit typically runs a parameter value stream at either the sample rate of the audio unit’s audio data, or some integer quotient of this (say a half or a third of the sample rate of the audio). The mSampleRate field in the AudioStreamBasicDescription structure describes this relationship. Uses no flags.

      Available in iOS 2.0 and later

    • kAudioFormatAppleLossless

      kAudioFormatAppleLossless

      Apple Lossless. Uses no flags.

      Available in iOS 2.0 and later

    • kAudioFormatMPEG4AAC_HE

      kAudioFormatMPEG4AAC_HE

      MPEG-4 High Efficiency AAC audio object. Uses no flags.

      Available in iOS 2.0 and later

    • kAudioFormatMPEG4AAC_LD

      kAudioFormatMPEG4AAC_LD

      MPEG-4 AAC Low Delay audio object. Uses no flags.

      Available in iOS 2.0 and later

    • kAudioFormatMPEG4AAC_ELD

      kAudioFormatMPEG4AAC_ELD

      MPEG-4 AAC Enhanced Low Delay audio object. Uses no flags.

      Available in iOS 4.0 and later

    • kAudioFormatMPEG4AAC_ELD_SBR

      kAudioFormatMPEG4AAC_ELD_SBR

      MPEG-4 AAC Enhanced Low Delay audio object with SBR (spectral band replication) extension layer. Uses no flags.

      Available in iOS 5.0 and later

    • kAudioFormatMPEG4AAC_HE_V2

      kAudioFormatMPEG4AAC_HE_V2

      MPEG-4 High Efficiency AAC Version 2 audio object. Uses no flags.

      Available in iOS 2.0 and later

    • kAudioFormatMPEG4AAC_Spatial

      kAudioFormatMPEG4AAC_Spatial

      MPEG-4 Spatial Audio audio object. Uses no flags.

      Available in iOS 2.0 and later

    • kAudioFormatAMR

      kAudioFormatAMR

      The AMR (Adaptive Multi-Rate) narrow band speech codec.

      Available in iOS 2.0 and later

    • kAudioFormatAudible

      kAudioFormatAudible

      The codec used for Audible, Inc. audio books. Uses no flags.

      Available in iOS 2.0 and later

    • kAudioFormatiLBC

      kAudioFormatiLBC

      The iLBC (internet Low Bitrate Codec) narrow band speech codec. Uses no flags.

      Available in iOS 2.0 and later

    • kAudioFormatDVIIntelIMA

      kAudioFormatDVIIntelIMA

      DVI/Intel IMA ADPCM - ACM code 17.

      Available in iOS 3.0 and later

    • kAudioFormatMicrosoftGSM

      kAudioFormatMicrosoftGSM

      Microsoft GSM 6.10 - ACM code 49.

      Available in iOS 3.0 and later

    • kAudioFormatAES3

      kAudioFormatAES3

      The format defined by the AES3-2003 standard. Adopted into MXF and MPEG-2 containers and SDTI transport streams with SMPTE specs 302M-2002 and 331M-2000. Uses no flags.

      Available in iOS 3.0 and later

    Discussion

    Use these identifiers to test for the presence of audio codecs on a system. If a given codec is present, you can use its identifier to specify that codec for data encoding or decoding, according to the capabilities of the codec. For more information, see Core Audio Overview.

  • Standard flags for use in the mFormatFlags field of the AudioStreamBasicDescription structure.

    Declaration

    Swift

    var kAudioFormatFlagIsFloat: Int { get } var kAudioFormatFlagIsBigEndian: Int { get } var kAudioFormatFlagIsSignedInteger: Int { get } var kAudioFormatFlagIsPacked: Int { get } var kAudioFormatFlagIsAlignedHigh: Int { get } var kAudioFormatFlagIsNonInterleaved: Int { get } var kAudioFormatFlagIsNonMixable: Int { get } var kLinearPCMFormatFlagsSampleFractionShift: Int { get } var kLinearPCMFormatFlagsSampleFractionMask: Int { get } var kAudioFormatFlagsAreAllClear: Int { get } var kLinearPCMFormatFlagIsFloat: Int { get } var kLinearPCMFormatFlagIsBigEndian: Int { get } var kLinearPCMFormatFlagIsSignedInteger: Int { get } var kLinearPCMFormatFlagIsPacked: Int { get } var kLinearPCMFormatFlagIsAlignedHigh: Int { get } var kLinearPCMFormatFlagIsNonInterleaved: Int { get } var kLinearPCMFormatFlagIsNonMixable: Int { get } var kLinearPCMFormatFlagsAreAllClear: Int { get } var kAppleLosslessFormatFlag_16BitSourceData: Int { get } var kAppleLosslessFormatFlag_20BitSourceData: Int { get } var kAppleLosslessFormatFlag_24BitSourceData: Int { get } var kAppleLosslessFormatFlag_32BitSourceData: Int { get }

    Objective-C

    enum { kAudioFormatFlagIsFloat = (1 << 0), // 0x1 kAudioFormatFlagIsBigEndian = (1 << 1), // 0x2 kAudioFormatFlagIsSignedInteger = (1 << 2), // 0x4 kAudioFormatFlagIsPacked = (1 << 3), // 0x8 kAudioFormatFlagIsAlignedHigh = (1 << 4), // 0x10 kAudioFormatFlagIsNonInterleaved = (1 << 5), // 0x20 kAudioFormatFlagIsNonMixable = (1 << 6), // 0x40 kAudioFormatFlagsAreAllClear = (1 << 31), kLinearPCMFormatFlagIsFloat = kAudioFormatFlagIsFloat, kLinearPCMFormatFlagIsBigEndian = kAudioFormatFlagIsBigEndian, kLinearPCMFormatFlagIsSignedInteger = kAudioFormatFlagIsSignedInteger, kLinearPCMFormatFlagIsPacked = kAudioFormatFlagIsPacked, kLinearPCMFormatFlagIsAlignedHigh = kAudioFormatFlagIsAlignedHigh, kLinearPCMFormatFlagIsNonInterleaved = kAudioFormatFlagIsNonInterleaved, kLinearPCMFormatFlagIsNonMixable = kAudioFormatFlagIsNonMixable, kLinearPCMFormatFlagsSampleFractionShift = 7, kLinearPCMFormatFlagsSampleFractionMask = (0x3F << kLinearPCMFormatFlagsSampleFractionShift ), kLinearPCMFormatFlagsAreAllClear = kAudioFormatFlagsAreAllClear, kAppleLosslessFormatFlag_16BitSourceData = 1, kAppleLosslessFormatFlag_20BitSourceData = 2, kAppleLosslessFormatFlag_24BitSourceData = 3, kAppleLosslessFormatFlag_32BitSourceData = 4 };

    Constants

    • kAudioFormatFlagIsFloat

      kAudioFormatFlagIsFloat

      Set for floating point, clear for integer.

      Available in iOS 2.0 and later

    • kAudioFormatFlagIsBigEndian

      kAudioFormatFlagIsBigEndian

      Set for big endian, clear for little endian.

      Available in iOS 2.0 and later

    • kAudioFormatFlagIsSignedInteger

      kAudioFormatFlagIsSignedInteger

      Set for signed integer, clear for unsigned integer. This is only valid if kAudioFormatFlagIsFloat is clear.

      Available in iOS 2.0 and later

    • kAudioFormatFlagIsPacked

      kAudioFormatFlagIsPacked

      Set if the sample bits occupy the entire available bits for the channel, clear if they are high- or low-aligned within the channel.

      Available in iOS 2.0 and later

    • kAudioFormatFlagIsAlignedHigh

      kAudioFormatFlagIsAlignedHigh

      Set if the sample bits are placed into the high bits of the channel, clear for low bit placement. This is only valid if kAudioFormatFlagIsPacked is clear.

      Available in iOS 2.0 and later

    • kAudioFormatFlagIsNonInterleaved

      kAudioFormatFlagIsNonInterleaved

      Set if the samples for each channel are located contiguously and the channels are laid out end to end, clear if the samples for each frame are laid out contiguously and the frames laid out end to end. This flag affects the use of the AudioStreamBasicDescription and AudioBufferList structures; see the discussion of the AudioStreamBasicDescription structure for details.

      Available in iOS 2.0 and later

    • kAudioFormatFlagIsNonMixable

      kAudioFormatFlagIsNonMixable

      Set to indicate when a format is nonmixable. Note that this flag is only used when interacting with the HAL's stream format information. It is not a valid flag for any other use.

      Available in iOS 2.0 and later

    • kLinearPCMFormatFlagsSampleFractionShift

      kLinearPCMFormatFlagsSampleFractionShift

      The linear PCM flags contain a 6-bit bitfield indicating that an integer format is to be interpreted as fixed point. The value indicates the number of bits are used to represent the fractional portion of each sample value. This constant indicates the bit position (counting from the right) of the bitfield in mFormatFlags field.

      Available in iOS 2.0 and later

    • kLinearPCMFormatFlagsSampleFractionMask

      kLinearPCMFormatFlagsSampleFractionMask

      <number_of_fractional_bits> = (mFormatFlags & kLinearPCMFormatFlagsSampleFractionMask) >> kLinearPCMFormatFlagsSampleFractionShift

      Available in iOS 2.0 and later

    • kAudioFormatFlagsAreAllClear

      kAudioFormatFlagsAreAllClear

      Set to indicate all the flags are clear. You must use this constant instead of 0, because a 0 in the mFormatFlags field of the AudioStreamBasicDescription structure indicates that there are no format flags.

      Available in iOS 2.0 and later

    • kLinearPCMFormatFlagIsFloat

      kLinearPCMFormatFlagIsFloat

      Synonym for kAudioFormatFlagIsFloat.

      Available in iOS 2.0 and later

    • kLinearPCMFormatFlagIsBigEndian

      kLinearPCMFormatFlagIsBigEndian

      Synonym for kAudioFormatFlagIsBigEndian.

      Available in iOS 2.0 and later

    • kLinearPCMFormatFlagIsSignedInteger

      kLinearPCMFormatFlagIsSignedInteger

      Synonym for kAudioFormatFlagIsSignedInteger.

      Available in iOS 2.0 and later

    • kLinearPCMFormatFlagIsPacked

      kLinearPCMFormatFlagIsPacked

      Synonym for kAudioFormatFlagIsPacked.

      Available in iOS 2.0 and later

    • kLinearPCMFormatFlagIsAlignedHigh

      kLinearPCMFormatFlagIsAlignedHigh

      Synonym for kAudioFormatFlagIsAlignedHigh.

      Available in iOS 2.0 and later

    • kLinearPCMFormatFlagIsNonInterleaved

      kLinearPCMFormatFlagIsNonInterleaved

      Synonym for kAudioFormatFlagIsNonInterleaved.

      Available in iOS 2.0 and later

    • kLinearPCMFormatFlagIsNonMixable

      kLinearPCMFormatFlagIsNonMixable

      Synonym for kAudioFormatFlagIsNonMixable.

      Available in iOS 2.0 and later

    • kLinearPCMFormatFlagsAreAllClear

      kLinearPCMFormatFlagsAreAllClear

      Synonym for kAudioFormatFlagsAreAllClear.

      Available in iOS 2.0 and later

    • kAppleLosslessFormatFlag_16BitSourceData

      kAppleLosslessFormatFlag_16BitSourceData

      This flag is set for Apple Lossless data that was sourced from 16 bit native endian signed integer data.

      Available in iOS 2.0 and later

    • kAppleLosslessFormatFlag_20BitSourceData

      kAppleLosslessFormatFlag_20BitSourceData

      Set for Apple Lossless data that was sourced from 20 bit native endian signed integer data aligned high in 24 bits.

      Available in iOS 2.0 and later

    • kAppleLosslessFormatFlag_24BitSourceData

      kAppleLosslessFormatFlag_24BitSourceData

      Set for Apple Lossless data that was sourced from 24 bit native endian signed integer data.

      Available in iOS 2.0 and later

    • kAppleLosslessFormatFlag_32BitSourceData

      kAppleLosslessFormatFlag_32BitSourceData

      Set for Apple Lossless data that was sourced from 32 bit native endian signed integer data.

      Available in iOS 2.0 and later

  • Commonly used combinations of data format flags for the AudioStreamBasicDescription structure.

    Declaration

    Swift

    var kAudioFormatFlagsNativeEndian: Int { get } var kAudioFormatFlagsNativeFloatPacked: Int { get }

    Objective-C

    enum { #if TARGET_RT_BIG_ENDIAN kAudioFormatFlagsNativeEndian = kAudioFormatFlagIsBigEndian, #else kAudioFormatFlagsNativeEndian = 0, #endif #if !CA_PREFER_FIXED_POINT kAudioFormatFlagsCanonical = kAudioFormatFlagIsFloat | kAudioFormatFlagsNativeEndian | kAudioFormatFlagIsPacked, kAudioFormatFlagsAudioUnitCanonical = kAudioFormatFlagIsFloat | kAudioFormatFlagsNativeEndian | kAudioFormatFlagIsPacked | kAudioFormatFlagIsNonInterleaved, #else kAudioFormatFlagsCanonical = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagsNativeEndian | kAudioFormatFlagIsPacked, kAudioFormatFlagsAudioUnitCanonical = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagsNativeEndian | kAudioFormatFlagIsPacked | kAudioFormatFlagIsNonInterleaved | (kAudioUnitSampleFractionBits << kLinearPCMFormatFlagsSampleFractionShift ), #endif kAudioFormatFlagsNativeFloatPacked = kAudioFormatFlagIsFloat | kAudioFormatFlagsNativeEndian | kAudioFormatFlagIsPacked };

    Constants

    • kAudioFormatFlagsNativeEndian

      kAudioFormatFlagsNativeEndian

      Defined to set or clear kAudioFormatFlagIsBigEndian depending on the endianness of the processor at build time.

      Available in iOS 2.0 and later

    • kAudioFormatFlagsCanonical

      kAudioFormatFlagsCanonical

      The set of flags for the canonical input-output audio sample type, which match the AudioSampleType type.

      Available in iOS 2.0 and later

      Deprecated in iOS 8.0

    • kAudioFormatFlagsAudioUnitCanonical

      kAudioFormatFlagsAudioUnitCanonical

      The flags for the canonical audio unit and processing sample type, which match the AudioUnitSampleType type.

      Available in iOS 2.0 and later

      Deprecated in iOS 8.0

    • kAudioFormatFlagsNativeFloatPacked

      kAudioFormatFlagsNativeFloatPacked

      The flags for the canonical format of fully packed, native endian floating point data.

      Available in iOS 2.0 and later

    Discussion

    Fixed-point formats are preferred in iPhone OS, while floating-point formats are preferred in OS X.

  • Used in the mFormatFlags field of an AudioStreamBasicDescription structure that describes an MPEG-4 audio stream to specify the type of MPEG-4 audio data.

    Deprecated in OS X v10.5.

    Declaration

    Swift

    var kMPEG4Object_AAC_Main: Int { get } var kMPEG4Object_AAC_LC: Int { get } var kMPEG4Object_AAC_SSR: Int { get } var kMPEG4Object_AAC_LTP: Int { get } var kMPEG4Object_AAC_SBR: Int { get } var kMPEG4Object_AAC_Scalable: Int { get } var kMPEG4Object_TwinVQ: Int { get } var kMPEG4Object_CELP: Int { get } var kMPEG4Object_HVXC: Int { get }

    Objective-C

    enum { kMPEG4Object_AAC_Main = 1, kMPEG4Object_AAC_LC = 2, kMPEG4Object_AAC_SSR = 3, kMPEG4Object_AAC_LTP = 4, kMPEG4Object_AAC_SBR = 5, kMPEG4Object_AAC_Scalable = 6, kMPEG4Object_TwinVQ = 7, kMPEG4Object_CELP = 8, kMPEG4Object_HVXC = 9 };

    Constants

    • kMPEG4Object_AAC_Main

      kMPEG4Object_AAC_Main

      Advanced audio coding; the basic MPEG-4 technology.

      Available in iOS 2.0 and later

    • kMPEG4Object_AAC_LC

      kMPEG4Object_AAC_LC

      Lossless coding; provides compression with no loss of quality.

      Available in iOS 2.0 and later

    • kMPEG4Object_AAC_SSR

      kMPEG4Object_AAC_SSR

      Scalable sampling rate; provides different sampling frequencies for different targets.

      Available in iOS 2.0 and later

    • kMPEG4Object_AAC_LTP

      kMPEG4Object_AAC_LTP

      Long term prediction; reduces redundancy in a coded signal.

      Available in iOS 2.0 and later

    • kMPEG4Object_AAC_SBR

      kMPEG4Object_AAC_SBR

      Spectral band replication; reconstructs high-frequency content from lower frequencies and side information.

      Available in iOS 2.0 and later

    • kMPEG4Object_AAC_Scalable

      kMPEG4Object_AAC_Scalable

      Scalable lossless coding.

      Available in iOS 2.0 and later

    • kMPEG4Object_TwinVQ

      kMPEG4Object_TwinVQ

      Transform-domain weighted interleaved vector quantization, an audio codec optimized for audio coding at ultra low bit rates around 8 kbit/s.

      Available in iOS 2.0 and later

    • kMPEG4Object_CELP

      kMPEG4Object_CELP

      Code Excited Linear Prediction, a narrow-band/wide-band speech codec.

      Available in iOS 2.0 and later

    • kMPEG4Object_HVXC

      kMPEG4Object_HVXC

      Harmonic Vector Excitation Coding, a very-low bit-rate parametric speech codec.

      Available in iOS 2.0 and later

    Discussion

    See the Moving Picture Experts Group web page (http://www.chiariglione.org/mpeg/) for details about MPEG technologies.

  • SMPTE timecode types, used in the SMPTETime structure.

    Declaration

    Swift

    var kSMPTETimeType24: Int { get } var kSMPTETimeType25: Int { get } var kSMPTETimeType30Drop: Int { get } var kSMPTETimeType30: Int { get } var kSMPTETimeType2997: Int { get } var kSMPTETimeType2997Drop: Int { get } var kSMPTETimeType60: Int { get } var kSMPTETimeType5994: Int { get } var kSMPTETimeType60Drop: Int { get } var kSMPTETimeType5994Drop: Int { get } var kSMPTETimeType50: Int { get } var kSMPTETimeType2398: Int { get }

    Objective-C

    enum { kSMPTETimeType24 = 0, kSMPTETimeType25 = 1, kSMPTETimeType30Drop = 2, kSMPTETimeType30 = 3, kSMPTETimeType2997 = 4, kSMPTETimeType2997Drop = 5, kSMPTETimeType60 = 6, kSMPTETimeType5994 = 7, kSMPTETimeType60Drop = 8, kSMPTETimeType5994Drop = 9, kSMPTETimeType50 = 10, kSMPTETimeType2398 = 11 };

    Constants

    • kSMPTETimeType24

      kSMPTETimeType24

      24 video frames per second—standard for 16mm and 35mm film.

      Available in iOS 2.0 and later

    • kSMPTETimeType25

      kSMPTETimeType25

      25 video frames per second—standard for PAL and SECAM video.

      Available in iOS 2.0 and later

    • kSMPTETimeType30Drop

      kSMPTETimeType30Drop

      30 video frames per second, with video-frame numbers adjusted to ensure that the timecode matches elapsed clock time.

      Available in iOS 2.0 and later

    • kSMPTETimeType30

      kSMPTETimeType30

      30 video frames per second.

      Available in iOS 2.0 and later

    • kSMPTETimeType2997

      kSMPTETimeType2997

      29.97 video frames per second—standard for NTSC video.

      Available in iOS 2.0 and later

    • kSMPTETimeType2997Drop

      kSMPTETimeType2997Drop

      29.97 video frames per second, with video-frame numbers adjusted to ensure that the timecode matches elapsed clock time.

      Available in iOS 2.0 and later

    • kSMPTETimeType60

      kSMPTETimeType60

      60 video frames per second.

      Available in iOS 2.0 and later

    • kSMPTETimeType5994

      kSMPTETimeType5994

      59.94 video frames per second.

      Available in iOS 2.0 and later

    • kSMPTETimeType60Drop

      kSMPTETimeType60Drop

      60 video frames per second, with video-frame numbers adjusted to ensure that the timecode matches elapsed clock time.

      Available in iOS 2.0 and later

    • kSMPTETimeType5994Drop

      kSMPTETimeType5994Drop

      59.94 video frames per second, with video-frame numbers adjusted to ensure that the timecode matches elapsed clock time.

      Available in iOS 2.0 and later

    • kSMPTETimeType50

      kSMPTETimeType50

      50 video frames per second.

      Available in iOS 2.0 and later

    • kSMPTETimeType2398

      kSMPTETimeType2398

      23.98 video frames per second.

      Available in iOS 2.0 and later

  • Flags that describe a SMPTE time state.

    Declaration

    Swift

    var kSMPTETimeValid: Int { get } var kSMPTETimeRunning: Int { get }

    Objective-C

    enum { kSMPTETimeValid = (1 << 0), kSMPTETimeRunning = (1 << 1) };

    Constants

    • kSMPTETimeValid

      kSMPTETimeValid

      The full time is valid.

      Available in iOS 2.0 and later

    • kSMPTETimeRunning

      kSMPTETimeRunning

      Time is running.

      Available in iOS 2.0 and later

  • These flags indicate the valid fields in an AudioTimeStamp structure.

    Declaration

    Swift

    var kAudioTimeStampSampleTimeValid: Int { get } var kAudioTimeStampHostTimeValid: Int { get } var kAudioTimeStampRateScalarValid: Int { get } var kAudioTimeStampWordClockTimeValid: Int { get } var kAudioTimeStampSMPTETimeValid: Int { get }

    Objective-C

    enum { kAudioTimeStampSampleTimeValid = (1 << 0), kAudioTimeStampHostTimeValid = (1 << 1), kAudioTimeStampRateScalarValid = (1 << 2), kAudioTimeStampWordClockTimeValid = (1 << 3), kAudioTimeStampSMPTETimeValid = (1 << 4) };

    Constants

    • kAudioTimeStampSampleTimeValid

      kAudioTimeStampSampleTimeValid

      The sample frame time is valid.

      Available in iOS 2.0 and later

    • kAudioTimeStampHostTimeValid

      kAudioTimeStampHostTimeValid

      The host time is valid.

      Available in iOS 2.0 and later

    • kAudioTimeStampRateScalarValid

      kAudioTimeStampRateScalarValid

      The rate scalar is valid.

      Available in iOS 2.0 and later

    • kAudioTimeStampWordClockTimeValid

      kAudioTimeStampWordClockTimeValid

      The word clock time is valid.

      Available in iOS 2.0 and later

    • kAudioTimeStampSMPTETimeValid

      kAudioTimeStampSMPTETimeValid

      The SMPTE time is valid.

      Available in iOS 2.0 and later

  • A commonly used combination of audio time stamp flags.

    Declaration

    Swift

    var kAudioTimeStampSampleHostTimeValid: Int { get }

    Objective-C

    enum { kAudioTimeStampSampleHostTimeValid = (kAudioTimeStampSampleTimeValid | kAudioTimeStampHostTimeValid ) };

    Constants

    • kAudioTimeStampSampleHostTimeValid

      kAudioTimeStampSampleHostTimeValid

      The sample frame time and the host time are valid.

      Available in iOS 2.0 and later

  • Channel labels for use in the mChannelLabel field of an AudioChannelDescription structure.

    Declaration

    Swift

    var kAudioChannelLabel_Unknown: UInt32 { get } var kAudioChannelLabel_Unused: UInt32 { get } var kAudioChannelLabel_UseCoordinates: UInt32 { get } var kAudioChannelLabel_Left: UInt32 { get } var kAudioChannelLabel_Right: UInt32 { get } var kAudioChannelLabel_Center: UInt32 { get } var kAudioChannelLabel_LFEScreen: UInt32 { get } var kAudioChannelLabel_LeftSurround: UInt32 { get } var kAudioChannelLabel_RightSurround: UInt32 { get } var kAudioChannelLabel_LeftCenter: UInt32 { get } var kAudioChannelLabel_RightCenter: UInt32 { get } var kAudioChannelLabel_CenterSurround: UInt32 { get } var kAudioChannelLabel_LeftSurroundDirect: UInt32 { get } var kAudioChannelLabel_RightSurroundDirect: UInt32 { get } var kAudioChannelLabel_TopCenterSurround: UInt32 { get } var kAudioChannelLabel_VerticalHeightLeft: UInt32 { get } var kAudioChannelLabel_VerticalHeightCenter: UInt32 { get } var kAudioChannelLabel_VerticalHeightRight: UInt32 { get } var kAudioChannelLabel_TopBackLeft: UInt32 { get } var kAudioChannelLabel_TopBackCenter: UInt32 { get } var kAudioChannelLabel_TopBackRight: UInt32 { get } var kAudioChannelLabel_RearSurroundLeft: UInt32 { get } var kAudioChannelLabel_RearSurroundRight: UInt32 { get } var kAudioChannelLabel_LeftWide: UInt32 { get } var kAudioChannelLabel_RightWide: UInt32 { get } var kAudioChannelLabel_LFE2: UInt32 { get } var kAudioChannelLabel_LeftTotal: UInt32 { get } var kAudioChannelLabel_RightTotal: UInt32 { get } var kAudioChannelLabel_HearingImpaired: UInt32 { get } var kAudioChannelLabel_Narration: UInt32 { get } var kAudioChannelLabel_Mono: UInt32 { get } var kAudioChannelLabel_DialogCentricMix: UInt32 { get } var kAudioChannelLabel_CenterSurroundDirect: UInt32 { get } var kAudioChannelLabel_Haptic: UInt32 { get } var kAudioChannelLabel_Ambisonic_W: UInt32 { get } var kAudioChannelLabel_Ambisonic_X: UInt32 { get } var kAudioChannelLabel_Ambisonic_Y: UInt32 { get } var kAudioChannelLabel_Ambisonic_Z: UInt32 { get } var kAudioChannelLabel_MS_Mid: UInt32 { get } var kAudioChannelLabel_MS_Side: UInt32 { get } var kAudioChannelLabel_XY_X: UInt32 { get } var kAudioChannelLabel_XY_Y: UInt32 { get } var kAudioChannelLabel_HeadphonesLeft: UInt32 { get } var kAudioChannelLabel_HeadphonesRight: UInt32 { get } var kAudioChannelLabel_ClickTrack: UInt32 { get } var kAudioChannelLabel_ForeignLanguage: UInt32 { get } var kAudioChannelLabel_Discrete: UInt32 { get } var kAudioChannelLabel_Discrete_0: UInt32 { get } var kAudioChannelLabel_Discrete_1: UInt32 { get } var kAudioChannelLabel_Discrete_2: UInt32 { get } var kAudioChannelLabel_Discrete_3: UInt32 { get } var kAudioChannelLabel_Discrete_4: UInt32 { get } var kAudioChannelLabel_Discrete_5: UInt32 { get } var kAudioChannelLabel_Discrete_6: UInt32 { get } var kAudioChannelLabel_Discrete_7: UInt32 { get } var kAudioChannelLabel_Discrete_8: UInt32 { get } var kAudioChannelLabel_Discrete_9: UInt32 { get } var kAudioChannelLabel_Discrete_10: UInt32 { get } var kAudioChannelLabel_Discrete_11: UInt32 { get } var kAudioChannelLabel_Discrete_12: UInt32 { get } var kAudioChannelLabel_Discrete_13: UInt32 { get } var kAudioChannelLabel_Discrete_14: UInt32 { get } var kAudioChannelLabel_Discrete_15: UInt32 { get } var kAudioChannelLabel_Discrete_65535: UInt32 { get }

    Objective-C

    enum { kAudioChannelLabel_Unknown = 0xFFFFFFFF, kAudioChannelLabel_Unused = 0, kAudioChannelLabel_UseCoordinates = 100, kAudioChannelLabel_Left = 1, kAudioChannelLabel_Right = 2, kAudioChannelLabel_Center = 3, kAudioChannelLabel_LFEScreen = 4, kAudioChannelLabel_LeftSurround = 5, kAudioChannelLabel_RightSurround = 6, kAudioChannelLabel_LeftCenter = 7, kAudioChannelLabel_RightCenter = 8, kAudioChannelLabel_CenterSurround = 9, kAudioChannelLabel_LeftSurroundDirect = 10, kAudioChannelLabel_RightSurroundDirect = 11, kAudioChannelLabel_TopCenterSurround = 12, kAudioChannelLabel_VerticalHeightLeft = 13, kAudioChannelLabel_VerticalHeightCenter = 14, kAudioChannelLabel_VerticalHeightRight = 15, kAudioChannelLabel_TopBackLeft = 16, kAudioChannelLabel_TopBackCenter = 17, kAudioChannelLabel_TopBackRight = 18, kAudioChannelLabel_RearSurroundLeft = 33, kAudioChannelLabel_RearSurroundRight = 34, kAudioChannelLabel_LeftWide = 35, kAudioChannelLabel_RightWide = 36, kAudioChannelLabel_LFE2 = 37, kAudioChannelLabel_LeftTotal = 38, kAudioChannelLabel_RightTotal = 39, kAudioChannelLabel_HearingImpaired = 40, kAudioChannelLabel_Narration = 41, kAudioChannelLabel_Mono = 42, kAudioChannelLabel_DialogCentricMix = 43, kAudioChannelLabel_CenterSurroundDirect = 44, kAudioChannelLabel_Haptic = 45, // first order ambisonic channels kAudioChannelLabel_Ambisonic_W = 200, kAudioChannelLabel_Ambisonic_X = 201, kAudioChannelLabel_Ambisonic_Y = 202, kAudioChannelLabel_Ambisonic_Z = 203, // Mid/Side Recording kAudioChannelLabel_MS_Mid = 204, kAudioChannelLabel_MS_Side = 205, // X-Y Recording kAudioChannelLabel_XY_X = 206, kAudioChannelLabel_XY_Y = 207, // other kAudioChannelLabel_HeadphonesLeft = 301, kAudioChannelLabel_HeadphonesRight = 302, kAudioChannelLabel_ClickTrack = 304, kAudioChannelLabel_ForeignLanguage = 305, // generic discrete channel kAudioChannelLabel_Discrete = 400, // numbered discrete channel kAudioChannelLabel_Discrete_0 = (1<<16) | 0, kAudioChannelLabel_Discrete_1 = (1<<16) | 1, kAudioChannelLabel_Discrete_2 = (1<<16) | 2, kAudioChannelLabel_Discrete_3 = (1<<16) | 3, kAudioChannelLabel_Discrete_4 = (1<<16) | 4, kAudioChannelLabel_Discrete_5 = (1<<16) | 5, kAudioChannelLabel_Discrete_6 = (1<<16) | 6, kAudioChannelLabel_Discrete_7 = (1<<16) | 7, kAudioChannelLabel_Discrete_8 = (1<<16) | 8, kAudioChannelLabel_Discrete_9 = (1<<16) | 9, kAudioChannelLabel_Discrete_10 = (1<<16) | 10, kAudioChannelLabel_Discrete_11 = (1<<16) | 11, kAudioChannelLabel_Discrete_12 = (1<<16) | 12, kAudioChannelLabel_Discrete_13 = (1<<16) | 13, kAudioChannelLabel_Discrete_14 = (1<<16) | 14, kAudioChannelLabel_Discrete_15 = (1<<16) | 15, kAudioChannelLabel_Discrete_65535 = (1<<16) | 65535 };

    Constants

    • kAudioChannelLabel_Unknown

      kAudioChannelLabel_Unknown

      Unknown role or unspecified other use for channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Unused

      kAudioChannelLabel_Unused

      The channel is present, but has no intended role or destination.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_UseCoordinates

      kAudioChannelLabel_UseCoordinates

      The channel is described solely by the mCoordinates field of the AudioChannelDescription structure.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Left

      kAudioChannelLabel_Left

      Left channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Right

      kAudioChannelLabel_Right

      Right channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Center

      kAudioChannelLabel_Center

      Center channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_LFEScreen

      kAudioChannelLabel_LFEScreen

      Low Frequency Effects Screen; a subwoofer located in front of the theater.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_LeftSurround

      kAudioChannelLabel_LeftSurround

      Left surround channel; or for WAVE (.wav) files, back left.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_RightSurround

      kAudioChannelLabel_RightSurround

      Right surround channel; or for WAVE (.wav) files, back right.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_LeftCenter

      kAudioChannelLabel_LeftCenter

      Left center channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_RightCenter

      kAudioChannelLabel_RightCenter

      Right center channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_CenterSurround

      kAudioChannelLabel_CenterSurround

      Center surround channel; or for WAVE (.wav) files, back center or rear surround.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_LeftSurroundDirect

      kAudioChannelLabel_LeftSurroundDirect

      Left surround direct channel; or for WAVE (.wav) files, side left.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_RightSurroundDirect

      kAudioChannelLabel_RightSurroundDirect

      Right surround direct channel; or for WAVE (.wav) files, side right.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_TopCenterSurround

      kAudioChannelLabel_TopCenterSurround

      Top center surround-sound channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_VerticalHeightLeft

      kAudioChannelLabel_VerticalHeightLeft

      Vertical height left channel; or for WAVE (.wav) files, top front left.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_VerticalHeightCenter

      kAudioChannelLabel_VerticalHeightCenter

      Vertical height center channel; or for WAVE (.wav) files, top front center.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_VerticalHeightRight

      kAudioChannelLabel_VerticalHeightRight

      Vertical height right channel; or for WAVE (.wav) files, top front right.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_TopBackLeft

      kAudioChannelLabel_TopBackLeft

      Top back left channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_TopBackCenter

      kAudioChannelLabel_TopBackCenter

      Top back center channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_TopBackRight

      kAudioChannelLabel_TopBackRight

      Top back right channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_RearSurroundLeft

      kAudioChannelLabel_RearSurroundLeft

      Rear surround left channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_RearSurroundRight

      kAudioChannelLabel_RearSurroundRight

      Rear surround right channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_LeftWide

      kAudioChannelLabel_LeftWide

      Left wide channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_RightWide

      kAudioChannelLabel_RightWide

      Right wide channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_LFE2

      kAudioChannelLabel_LFE2

      Low Frequency Effects 2.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_LeftTotal

      kAudioChannelLabel_LeftTotal

      The left channel of matrix encoded 4 channel audio.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_RightTotal

      kAudioChannelLabel_RightTotal

      The right channel of matrix encoded 4 channel audio.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_HearingImpaired

      kAudioChannelLabel_HearingImpaired

      Channel carrying audio for the hearing impaired.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Narration

      kAudioChannelLabel_Narration

      Narration channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Mono

      kAudioChannelLabel_Mono

      Monaural channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_DialogCentricMix

      kAudioChannelLabel_DialogCentricMix

      Available in iOS 2.0 and later

    • kAudioChannelLabel_CenterSurroundDirect

      kAudioChannelLabel_CenterSurroundDirect

      Back center, non diffuse channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Haptic

      kAudioChannelLabel_Haptic

      A channel for haptic (touch) data.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Ambisonic_W

      kAudioChannelLabel_Ambisonic_W

      First order Ambisonic channel W.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Ambisonic_X

      kAudioChannelLabel_Ambisonic_X

      First order Ambisonic channel X.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Ambisonic_Y

      kAudioChannelLabel_Ambisonic_Y

      First order Ambisonic channel Y.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Ambisonic_Z

      kAudioChannelLabel_Ambisonic_Z

      First order Ambisonic channel Z.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_MS_Mid

      kAudioChannelLabel_MS_Mid

      Mid channel of a Mid/Side recording.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_MS_Side

      kAudioChannelLabel_MS_Side

      Side channel of a Mid/Side recording.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_XY_X

      kAudioChannelLabel_XY_X

      X channel of an X-Y recording.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_XY_Y

      kAudioChannelLabel_XY_Y

      Y channel of an X-Y recording.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_HeadphonesLeft

      kAudioChannelLabel_HeadphonesLeft

      Left channel of stereo headphones.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_HeadphonesRight

      kAudioChannelLabel_HeadphonesRight

      Right channel of stereo headphones.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_ClickTrack

      kAudioChannelLabel_ClickTrack

      Click track channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_ForeignLanguage

      kAudioChannelLabel_ForeignLanguage

      Foreign language channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete

      kAudioChannelLabel_Discrete

      Generic discrete channel.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_0

      kAudioChannelLabel_Discrete_0

      Discrete channel 0.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_1

      kAudioChannelLabel_Discrete_1

      Discrete channel 1.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_2

      kAudioChannelLabel_Discrete_2

      Discrete channel 2.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_3

      kAudioChannelLabel_Discrete_3

      Discrete channel 3.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_4

      kAudioChannelLabel_Discrete_4

      Discrete channel 4.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_5

      kAudioChannelLabel_Discrete_5

      Discrete channel 5.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_6

      kAudioChannelLabel_Discrete_6

      Discrete channel 6.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_7

      kAudioChannelLabel_Discrete_7

      Discrete channel 7.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_8

      kAudioChannelLabel_Discrete_8

      Discrete channel 8.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_9

      kAudioChannelLabel_Discrete_9

      Discrete channel 9.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_10

      kAudioChannelLabel_Discrete_10

      Discrete channel 10.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_11

      kAudioChannelLabel_Discrete_11

      Discrete channel 11.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_12

      kAudioChannelLabel_Discrete_12

      Discrete channel 12.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_13

      kAudioChannelLabel_Discrete_13

      Discrete channel 13.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_14

      kAudioChannelLabel_Discrete_14

      Discrete channel 14.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_15

      kAudioChannelLabel_Discrete_15

      Discrete channel 15.

      Available in iOS 2.0 and later

    • kAudioChannelLabel_Discrete_65535

      kAudioChannelLabel_Discrete_65535

      Discrete channel 65536.

      Available in iOS 2.0 and later

  • Channel bits for use in the mChannelBitmap field of an AudioChannelLayout structure.

    Declaration

    Swift

    var kAudioChannelBit_Left: Int { get } var kAudioChannelBit_Right: Int { get } var kAudioChannelBit_Center: Int { get } var kAudioChannelBit_LFEScreen: Int { get } var kAudioChannelBit_LeftSurround: Int { get } var kAudioChannelBit_RightSurround: Int { get } var kAudioChannelBit_LeftCenter: Int { get } var kAudioChannelBit_RightCenter: Int { get } var kAudioChannelBit_CenterSurround: Int { get } var kAudioChannelBit_LeftSurroundDirect: Int { get } var kAudioChannelBit_RightSurroundDirect: Int { get } var kAudioChannelBit_TopCenterSurround: Int { get } var kAudioChannelBit_VerticalHeightLeft: Int { get } var kAudioChannelBit_VerticalHeightCenter: Int { get } var kAudioChannelBit_VerticalHeightRight: Int { get } var kAudioChannelBit_TopBackLeft: Int { get } var kAudioChannelBit_TopBackCenter: Int { get } var kAudioChannelBit_TopBackRight: Int { get }

    Objective-C

    enum { kAudioChannelBit_Left = (1<<0), kAudioChannelBit_Right = (1<<1), kAudioChannelBit_Center = (1<<2), kAudioChannelBit_LFEScreen = (1<<3), kAudioChannelBit_LeftSurround = (1<<4), kAudioChannelBit_RightSurround = (1<<5), kAudioChannelBit_LeftCenter = (1<<6), kAudioChannelBit_RightCenter = (1<<7), kAudioChannelBit_CenterSurround = (1<<8), kAudioChannelBit_LeftSurroundDirect = (1<<9), kAudioChannelBit_RightSurroundDirect = (1<<10), kAudioChannelBit_TopCenterSurround = (1<<11), kAudioChannelBit_VerticalHeightLeft = (1<<12), kAudioChannelBit_VerticalHeightCenter = (1<<13), kAudioChannelBit_VerticalHeightRight = (1<<14), kAudioChannelBit_TopBackLeft = (1<<15), kAudioChannelBit_TopBackCenter = (1<<16), kAudioChannelBit_TopBackRight = (1<<17) };

    Constants

    • kAudioChannelBit_Left

      kAudioChannelBit_Left

      Left channel.

      Available in iOS 2.0 and later

    • kAudioChannelBit_Right

      kAudioChannelBit_Right

      Right channel.

      Available in iOS 2.0 and later

    • kAudioChannelBit_Center

      kAudioChannelBit_Center

      Center channel.

      Available in iOS 2.0 and later

    • kAudioChannelBit_LFEScreen

      kAudioChannelBit_LFEScreen

      Low Frequency Effects screen channel.

      Available in iOS 2.0 and later

    • kAudioChannelBit_LeftSurround

      kAudioChannelBit_LeftSurround

      Left surround channel; or for WAVE (.wav) files, back left.

      Available in iOS 2.0 and later

    • kAudioChannelBit_RightSurround

      kAudioChannelBit_RightSurround

      RIght surround channel; or for WAVE (.wav) files, back right.

      Available in iOS 2.0 and later

    • kAudioChannelBit_LeftCenter

      kAudioChannelBit_LeftCenter

      Left center channel.

      Available in iOS 2.0 and later

    • kAudioChannelBit_RightCenter

      kAudioChannelBit_RightCenter

      Right center channel.

      Available in iOS 2.0 and later

    • kAudioChannelBit_CenterSurround

      kAudioChannelBit_CenterSurround

      Center surround channel; or for WAVE (.wav) files, back center.

      Available in iOS 2.0 and later

    • kAudioChannelBit_LeftSurroundDirect

      kAudioChannelBit_LeftSurroundDirect

      Left surround direct channel; or for WAVE (.wav) files, side left.

      Available in iOS 2.0 and later

    • kAudioChannelBit_RightSurroundDirect

      kAudioChannelBit_RightSurroundDirect

      Right surround direct channel; or for WAVE (.wav) files, side right.

      Available in iOS 2.0 and later

    • kAudioChannelBit_TopCenterSurround

      kAudioChannelBit_TopCenterSurround

      To center surround channel.

      Available in iOS 2.0 and later

    • kAudioChannelBit_VerticalHeightLeft

      kAudioChannelBit_VerticalHeightLeft

      Vertical height left channel; or for WAVE (.wav) files, top front left.

      Available in iOS 2.0 and later

    • kAudioChannelBit_VerticalHeightCenter

      kAudioChannelBit_VerticalHeightCenter

      Vertical height center channel; or for WAVE (.wav) files, top front center.

      Available in iOS 2.0 and later

    • kAudioChannelBit_VerticalHeightRight

      kAudioChannelBit_VerticalHeightRight

      Vertical height right channel; or for WAVE (.wav) files, top front right.

      Available in iOS 2.0 and later

    • kAudioChannelBit_TopBackLeft

      kAudioChannelBit_TopBackLeft

      Top back left channel.

      Available in iOS 2.0 and later

    • kAudioChannelBit_TopBackCenter

      kAudioChannelBit_TopBackCenter

      Top back center channel.

      Available in iOS 2.0 and later

    • kAudioChannelBit_TopBackRight

      kAudioChannelBit_TopBackRight

      Top back right channel.

      Available in iOS 2.0 and later

  • Used in the mChannelFlags field of an AudioChannelDescription structure.

    Declaration

    Swift

    var kAudioChannelFlags_AllOff: Int { get } var kAudioChannelFlags_RectangularCoordinates: Int { get } var kAudioChannelFlags_SphericalCoordinates: Int { get } var kAudioChannelFlags_Meters: Int { get }

    Objective-C

    enum { kAudioChannelFlags_AllOff = 0, kAudioChannelFlags_RectangularCoordinates = (1<<0), kAudioChannelFlags_SphericalCoordinates = (1<<1), kAudioChannelFlags_Meters = (1<<2) };

    Constants

    • kAudioChannelFlags_AllOff

      kAudioChannelFlags_AllOff

      All flags are clear.

      Available in iOS 2.0 and later

    • kAudioChannelFlags_RectangularCoordinates

      kAudioChannelFlags_RectangularCoordinates

      Set to indicate the channel is specified by the Cartesian coordinates of the speaker position. This flag is mutually exclusive with kAudioChannelFlags_SphericalCoordinates.

      Available in iOS 2.0 and later

    • kAudioChannelFlags_SphericalCoordinates

      kAudioChannelFlags_SphericalCoordinates

      Set to indicate the channel is specified by the spherical coordinates of the speaker position. This flag is mutually exclusive with kAudioChannelFlags_RectangularCoordinates.

      Available in iOS 2.0 and later

    • kAudioChannelFlags_Meters

      kAudioChannelFlags_Meters

      Set to indicate the units are in meters, clear to indicate the units are relative to the unit cube or unit sphere. For relative units, the listener is assumed to be at the center of the cube or sphere and the radius of the sphere or the distance from the center to the midpoint of the side of the cube is 1.

      Available in iOS 2.0 and later

  • Indexes the fields of the mCoordinates array in an AudioChannelDescription structure.

    Declaration

    Swift

    var kAudioChannelCoordinates_LeftRight: Int { get } var kAudioChannelCoordinates_BackFront: Int { get } var kAudioChannelCoordinates_DownUp: Int { get } var kAudioChannelCoordinates_Azimuth: Int { get } var kAudioChannelCoordinates_Elevation: Int { get } var kAudioChannelCoordinates_Distance: Int { get }

    Objective-C

    enum { kAudioChannelCoordinates_LeftRight = 0, kAudioChannelCoordinates_BackFront = 1, kAudioChannelCoordinates_DownUp = 2, kAudioChannelCoordinates_Azimuth = 0, kAudioChannelCoordinates_Elevation = 1, kAudioChannelCoordinates_Distance = 2 };

    Constants

    • kAudioChannelCoordinates_LeftRight

      kAudioChannelCoordinates_LeftRight

      For rectangular coordinates, negative is left and positive is right. The units are specified by the mChannelFlags field of the AudioChannelDescription structure.

      Available in iOS 2.0 and later

    • kAudioChannelCoordinates_BackFront

      kAudioChannelCoordinates_BackFront

      For rectangular coordinates, negative is back and positive is front. The units are specified by the mChannelFlags field.

      Available in iOS 2.0 and later

    • kAudioChannelCoordinates_DownUp

      kAudioChannelCoordinates_DownUp

      For rectangular coordinates, negative is below ground level, 0 is ground level, and positive is above ground level. The units are specified by the mChannelFlags field.

      Available in iOS 2.0 and later

    • kAudioChannelCoordinates_Azimuth

      kAudioChannelCoordinates_Azimuth

      For spherical coordinates, 0 is front center, positive is right, negative is left, and measurements are in degrees.

      Available in iOS 2.0 and later

    • kAudioChannelCoordinates_Elevation

      kAudioChannelCoordinates_Elevation

      For spherical coordinates, +90 is zenith, 0 is horizontal, -90 is nadir, and measurements are in degrees.

      Available in iOS 2.0 and later

    • kAudioChannelCoordinates_Distance

      kAudioChannelCoordinates_Distance

      For spherical coordinates, distance is radially from the center. The units are specified by the mChannelFlags field of the AudioChannelDescription structure.

      Available in iOS 2.0 and later

  • 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 mChannelLayoutTag field of an AudioChannelLayout structure.

    Declaration

    Swift

    var kAudioChannelLayoutTag_UseChannelDescriptions: UInt32 { get } var kAudioChannelLayoutTag_UseChannelBitmap: UInt32 { get } var kAudioChannelLayoutTag_Mono: UInt32 { get } var kAudioChannelLayoutTag_Stereo: UInt32 { get } var kAudioChannelLayoutTag_StereoHeadphones: UInt32 { get } var kAudioChannelLayoutTag_MatrixStereo: UInt32 { get } var kAudioChannelLayoutTag_MidSide: UInt32 { get } var kAudioChannelLayoutTag_XY: UInt32 { get } var kAudioChannelLayoutTag_Binaural: UInt32 { get } var kAudioChannelLayoutTag_Ambisonic_B_Format: UInt32 { get } var kAudioChannelLayoutTag_Quadraphonic: UInt32 { get } var kAudioChannelLayoutTag_Pentagonal: UInt32 { get } var kAudioChannelLayoutTag_Hexagonal: UInt32 { get } var kAudioChannelLayoutTag_Octagonal: UInt32 { get } var kAudioChannelLayoutTag_Cube: UInt32 { get } var kAudioChannelLayoutTag_MPEG_1_0: UInt32 { get } var kAudioChannelLayoutTag_MPEG_2_0: UInt32 { get } var kAudioChannelLayoutTag_MPEG_3_0_A: UInt32 { get } var kAudioChannelLayoutTag_MPEG_3_0_B: UInt32 { get } var kAudioChannelLayoutTag_MPEG_4_0_A: UInt32 { get } var kAudioChannelLayoutTag_MPEG_4_0_B: UInt32 { get } var kAudioChannelLayoutTag_MPEG_5_0_A: UInt32 { get } var kAudioChannelLayoutTag_MPEG_5_0_B: UInt32 { get } var kAudioChannelLayoutTag_MPEG_5_0_C: UInt32 { get } var kAudioChannelLayoutTag_MPEG_5_0_D: UInt32 { get } var kAudioChannelLayoutTag_MPEG_5_1_A: UInt32 { get } var kAudioChannelLayoutTag_MPEG_5_1_B: UInt32 { get } var kAudioChannelLayoutTag_MPEG_5_1_C: UInt32 { get } var kAudioChannelLayoutTag_MPEG_5_1_D: UInt32 { get } var kAudioChannelLayoutTag_MPEG_6_1_A: UInt32 { get } var kAudioChannelLayoutTag_MPEG_7_1_A: UInt32 { get } var kAudioChannelLayoutTag_MPEG_7_1_B: UInt32 { get } var kAudioChannelLayoutTag_MPEG_7_1_C: UInt32 { get } var kAudioChannelLayoutTag_Emagic_Default_7_1: UInt32 { get } var kAudioChannelLayoutTag_SMPTE_DTV: UInt32 { get } var kAudioChannelLayoutTag_ITU_1_0: UInt32 { get } var kAudioChannelLayoutTag_ITU_2_0: UInt32 { get } var kAudioChannelLayoutTag_ITU_2_1: UInt32 { get } var kAudioChannelLayoutTag_ITU_2_2: UInt32 { get } var kAudioChannelLayoutTag_ITU_3_0: UInt32 { get } var kAudioChannelLayoutTag_ITU_3_1: UInt32 { get } var kAudioChannelLayoutTag_ITU_3_2: UInt32 { get } var kAudioChannelLayoutTag_ITU_3_2_1: UInt32 { get } var kAudioChannelLayoutTag_ITU_3_4_1: UInt32 { get } var kAudioChannelLayoutTag_DVD_0: UInt32 { get } var kAudioChannelLayoutTag_DVD_1: UInt32 { get } var kAudioChannelLayoutTag_DVD_2: UInt32 { get } var kAudioChannelLayoutTag_DVD_3: UInt32 { get } var kAudioChannelLayoutTag_DVD_4: UInt32 { get } var kAudioChannelLayoutTag_DVD_5: UInt32 { get } var kAudioChannelLayoutTag_DVD_6: UInt32 { get } var kAudioChannelLayoutTag_DVD_7: UInt32 { get } var kAudioChannelLayoutTag_DVD_8: UInt32 { get } var kAudioChannelLayoutTag_DVD_9: UInt32 { get } var kAudioChannelLayoutTag_DVD_10: UInt32 { get } var kAudioChannelLayoutTag_DVD_11: UInt32 { get } var kAudioChannelLayoutTag_DVD_12: UInt32 { get } var kAudioChannelLayoutTag_DVD_13: UInt32 { get } var kAudioChannelLayoutTag_DVD_14: UInt32 { get } var kAudioChannelLayoutTag_DVD_15: UInt32 { get } var kAudioChannelLayoutTag_DVD_16: UInt32 { get } var kAudioChannelLayoutTag_DVD_17: UInt32 { get } var kAudioChannelLayoutTag_DVD_18: UInt32 { get } var kAudioChannelLayoutTag_DVD_19: UInt32 { get } var kAudioChannelLayoutTag_DVD_20: UInt32 { get } var kAudioChannelLayoutTag_AudioUnit_4: UInt32 { get } var kAudioChannelLayoutTag_AudioUnit_5: UInt32 { get } var kAudioChannelLayoutTag_AudioUnit_6: UInt32 { get } var kAudioChannelLayoutTag_AudioUnit_8: UInt32 { get } var kAudioChannelLayoutTag_AudioUnit_5_0: UInt32 { get } var kAudioChannelLayoutTag_AudioUnit_6_0: UInt32 { get } var kAudioChannelLayoutTag_AudioUnit_7_0: UInt32 { get } var kAudioChannelLayoutTag_AudioUnit_7_0_Front: UInt32 { get } var kAudioChannelLayoutTag_AudioUnit_5_1: UInt32 { get } var kAudioChannelLayoutTag_AudioUnit_6_1: UInt32 { get } var kAudioChannelLayoutTag_AudioUnit_7_1: UInt32 { get } var kAudioChannelLayoutTag_AudioUnit_7_1_Front: UInt32 { get } var kAudioChannelLayoutTag_AAC_3_0: UInt32 { get } var kAudioChannelLayoutTag_AAC_Quadraphonic: UInt32 { get } var kAudioChannelLayoutTag_AAC_4_0: UInt32 { get } var kAudioChannelLayoutTag_AAC_5_0: UInt32 { get } var kAudioChannelLayoutTag_AAC_5_1: UInt32 { get } var kAudioChannelLayoutTag_AAC_6_0: UInt32 { get } var kAudioChannelLayoutTag_AAC_6_1: UInt32 { get } var kAudioChannelLayoutTag_AAC_7_0: UInt32 { get } var kAudioChannelLayoutTag_AAC_7_1: UInt32 { get } var kAudioChannelLayoutTag_AAC_Octagonal: UInt32 { get } var kAudioChannelLayoutTag_TMH_10_2_std: UInt32 { get } var kAudioChannelLayoutTag_TMH_10_2_full: UInt32 { get } var kAudioChannelLayoutTag_AC3_1_0_1: UInt32 { get } var kAudioChannelLayoutTag_AC3_3_0: UInt32 { get } var kAudioChannelLayoutTag_AC3_3_1: UInt32 { get } var kAudioChannelLayoutTag_AC3_3_0_1: UInt32 { get } var kAudioChannelLayoutTag_AC3_2_1_1: UInt32 { get } var kAudioChannelLayoutTag_AC3_3_1_1: UInt32 { get } var kAudioChannelLayoutTag_EAC_6_0_A: UInt32 { get } var kAudioChannelLayoutTag_EAC_7_0_A: UInt32 { get } var kAudioChannelLayoutTag_EAC3_6_1_A: UInt32 { get } var kAudioChannelLayoutTag_EAC3_6_1_B: UInt32 { get } var kAudioChannelLayoutTag_EAC3_6_1_C: UInt32 { get } var kAudioChannelLayoutTag_EAC3_7_1_A: UInt32 { get } var kAudioChannelLayoutTag_EAC3_7_1_B: UInt32 { get } var kAudioChannelLayoutTag_EAC3_7_1_C: UInt32 { get } var kAudioChannelLayoutTag_EAC3_7_1_D: UInt32 { get } var kAudioChannelLayoutTag_EAC3_7_1_E: UInt32 { get } var kAudioChannelLayoutTag_EAC3_7_1_F: UInt32 { get } var kAudioChannelLayoutTag_EAC3_7_1_G: UInt32 { get } var kAudioChannelLayoutTag_EAC3_7_1_H: UInt32 { get } var kAudioChannelLayoutTag_DTS_3_1: UInt32 { get } var kAudioChannelLayoutTag_DTS_4_1: UInt32 { get } var kAudioChannelLayoutTag_DTS_6_0_A: UInt32 { get } var kAudioChannelLayoutTag_DTS_6_0_B: UInt32 { get } var kAudioChannelLayoutTag_DTS_6_0_C: UInt32 { get } var kAudioChannelLayoutTag_DTS_6_1_A: UInt32 { get } var kAudioChannelLayoutTag_DTS_6_1_B: UInt32 { get } var kAudioChannelLayoutTag_DTS_6_1_C: UInt32 { get } var kAudioChannelLayoutTag_DTS_6_1_D: UInt32 { get } var kAudioChannelLayoutTag_DTS_7_0: UInt32 { get } var kAudioChannelLayoutTag_DTS_7_1: UInt32 { get } var kAudioChannelLayoutTag_DTS_8_0_A: UInt32 { get } var kAudioChannelLayoutTag_DTS_8_0_B: UInt32 { get } var kAudioChannelLayoutTag_DTS_8_1_A: UInt32 { get } var kAudioChannelLayoutTag_DTS_8_1_B: UInt32 { get } var kAudioChannelLayoutTag_DiscreteInOrder: UInt32 { get } var kAudioChannelLayoutTag_Unknown: UInt32 { get }

    Objective-C

    enum { kAudioChannelLayoutTag_UseChannelDescriptions = (0<<16) | 0, kAudioChannelLayoutTag_UseChannelBitmap = (1<<16) | 0, // General layouts kAudioChannelLayoutTag_Mono = (100<<16) | 1, kAudioChannelLayoutTag_Stereo = (101<<16) | 2, kAudioChannelLayoutTag_StereoHeadphones = (102<<16) | 2, kAudioChannelLayoutTag_MatrixStereo = (103<<16) | 2, kAudioChannelLayoutTag_MidSide = (104<<16) | 2, kAudioChannelLayoutTag_XY = (105<<16) | 2, kAudioChannelLayoutTag_Binaural = (106<<16) | 2, kAudioChannelLayoutTag_Ambisonic_B_Format = (107<<16) | 4, kAudioChannelLayoutTag_Quadraphonic = (108<<16) | 4, kAudioChannelLayoutTag_Pentagonal = (109<<16) | 5, kAudioChannelLayoutTag_Hexagonal = (110<<16) | 6, kAudioChannelLayoutTag_Octagonal = (111<<16) | 8, kAudioChannelLayoutTag_Cube = (112<<16) | 8, // MPEG defined layouts kAudioChannelLayoutTag_MPEG_1_0 = kAudioChannelLayoutTag_Mono, kAudioChannelLayoutTag_MPEG_2_0 = kAudioChannelLayoutTag_Stereo, kAudioChannelLayoutTag_MPEG_3_0_A = (113<<16) | 3, kAudioChannelLayoutTag_MPEG_3_0_B = (114<<16) | 3, kAudioChannelLayoutTag_MPEG_4_0_A = (115<<16) | 4, kAudioChannelLayoutTag_MPEG_4_0_B = (116<<16) | 4, kAudioChannelLayoutTag_MPEG_5_0_A = (117<<16) | 5, kAudioChannelLayoutTag_MPEG_5_0_B = (118<<16) | 5, kAudioChannelLayoutTag_MPEG_5_0_C = (119<<16) | 5, kAudioChannelLayoutTag_MPEG_5_0_D = (120<<16) | 5, kAudioChannelLayoutTag_MPEG_5_1_A = (121<<16) | 6, kAudioChannelLayoutTag_MPEG_5_1_B = (122<<16) | 6, kAudioChannelLayoutTag_MPEG_5_1_C = (123<<16) | 6, kAudioChannelLayoutTag_MPEG_5_1_D = (124<<16) | 6, kAudioChannelLayoutTag_MPEG_6_1_A = (125<<16) | 7, kAudioChannelLayoutTag_MPEG_7_1_A = (126<<16) | 8, kAudioChannelLayoutTag_MPEG_7_1_B = (127<<16) | 8, kAudioChannelLayoutTag_MPEG_7_1_C = (128<<16) | 8, kAudioChannelLayoutTag_Emagic_Default_7_1 = (129<<16) | 8, kAudioChannelLayoutTag_SMPTE_DTV = (130<<16) | 8, // ITU defined layouts kAudioChannelLayoutTag_ITU_1_0 = kAudioChannelLayoutTag_Mono, kAudioChannelLayoutTag_ITU_2_0 = kAudioChannelLayoutTag_Stereo, kAudioChannelLayoutTag_ITU_2_1 = (131<<16) | 3, kAudioChannelLayoutTag_ITU_2_2 = (132<<16) | 4, kAudioChannelLayoutTag_ITU_3_0 = kAudioChannelLayoutTag_MPEG_3_0_A, kAudioChannelLayoutTag_ITU_3_1 = kAudioChannelLayoutTag_MPEG_4_0_A, kAudioChannelLayoutTag_ITU_3_2 = kAudioChannelLayoutTag_MPEG_5_0_A, kAudioChannelLayoutTag_ITU_3_2_1 = kAudioChannelLayoutTag_MPEG_5_1_A, kAudioChannelLayoutTag_ITU_3_4_1 = kAudioChannelLayoutTag_MPEG_7_1_C, // DVD defined layouts kAudioChannelLayoutTag_DVD_0 = kAudioChannelLayoutTag_Mono, kAudioChannelLayoutTag_DVD_1 = kAudioChannelLayoutTag_Stereo, kAudioChannelLayoutTag_DVD_2 = kAudioChannelLayoutTag_ITU_2_1, kAudioChannelLayoutTag_DVD_3 = kAudioChannelLayoutTag_ITU_2_2, kAudioChannelLayoutTag_DVD_4 = (133<<16) | 3, kAudioChannelLayoutTag_DVD_5 = (134<<16) | 4, kAudioChannelLayoutTag_DVD_6 = (135<<16) | 5, kAudioChannelLayoutTag_DVD_7 = kAudioChannelLayoutTag_MPEG_3_0_A, kAudioChannelLayoutTag_DVD_8 = kAudioChannelLayoutTag_MPEG_4_0_A, kAudioChannelLayoutTag_DVD_9 = kAudioChannelLayoutTag_MPEG_5_0_A, kAudioChannelLayoutTag_DVD_10 = (136<<16) | 4, kAudioChannelLayoutTag_DVD_11 = (137<<16) | 5, kAudioChannelLayoutTag_DVD_12 = kAudioChannelLayoutTag_MPEG_5_1_A, kAudioChannelLayoutTag_DVD_13 = kAudioChannelLayoutTag_DVD_8, kAudioChannelLayoutTag_DVD_14 = kAudioChannelLayoutTag_DVD_9, kAudioChannelLayoutTag_DVD_15 = kAudioChannelLayoutTag_DVD_10, kAudioChannelLayoutTag_DVD_16 = kAudioChannelLayoutTag_DVD_11, kAudioChannelLayoutTag_DVD_17 = kAudioChannelLayoutTag_DVD_12, kAudioChannelLayoutTag_DVD_18 = (138<<16) | 5, kAudioChannelLayoutTag_DVD_19 = kAudioChannelLayoutTag_MPEG_5_0_B, kAudioChannelLayoutTag_DVD_20 = kAudioChannelLayoutTag_MPEG_5_1_B, // These layouts are recommended for AudioUnit use; // these are the symmetrical layouts kAudioChannelLayoutTag_AudioUnit_4 = kAudioChannelLayoutTag_Quadraphonic, kAudioChannelLayoutTag_AudioUnit_5 = kAudioChannelLayoutTag_Pentagonal, kAudioChannelLayoutTag_AudioUnit_6 = kAudioChannelLayoutTag_Hexagonal, kAudioChannelLayoutTag_AudioUnit_8 = kAudioChannelLayoutTag_Octagonal, // These are the surround-based layouts kAudioChannelLayoutTag_AudioUnit_5_0 = kAudioChannelLayoutTag_MPEG_5_0_B, kAudioChannelLayoutTag_AudioUnit_6_0 = (139<<16) | 6, kAudioChannelLayoutTag_AudioUnit_7_0 = (140<<16) | 7, kAudioChannelLayoutTag_AudioUnit_7_0_Front = (148<<16) | 7, kAudioChannelLayoutTag_AudioUnit_5_1 = kAudioChannelLayoutTag_MPEG_5_1_A, kAudioChannelLayoutTag_AudioUnit_6_1 = kAudioChannelLayoutTag_MPEG_6_1_A, kAudioChannelLayoutTag_AudioUnit_7_1 = kAudioChannelLayoutTag_MPEG_7_1_C, kAudioChannelLayoutTag_AudioUnit_7_1_Front = kAudioChannelLayoutTag_MPEG_7_1_A, kAudioChannelLayoutTag_AAC_3_0 = kAudioChannelLayoutTag_MPEG_3_0_B, kAudioChannelLayoutTag_AAC_Quadraphonic = kAudioChannelLayoutTag_Quadraphonic, kAudioChannelLayoutTag_AAC_4_0 = kAudioChannelLayoutTag_MPEG_4_0_B, kAudioChannelLayoutTag_AAC_5_0 = kAudioChannelLayoutTag_MPEG_5_0_D, kAudioChannelLayoutTag_AAC_5_1 = kAudioChannelLayoutTag_MPEG_5_1_D, kAudioChannelLayoutTag_AAC_6_0 = (141<<16) | 6, kAudioChannelLayoutTag_AAC_6_1 = (142<<16) | 7, kAudioChannelLayoutTag_AAC_7_0 = (143<<16) | 7, kAudioChannelLayoutTag_AAC_7_1 = kAudioChannelLayoutTag_MPEG_7_1_B, kAudioChannelLayoutTag_AAC_Octagonal = (144<<16) | 8, kAudioChannelLayoutTag_TMH_10_2_std = (145<<16) | 16, kAudioChannelLayoutTag_TMH_10_2_full = (146<<16) | 21, kAudioChannelLayoutTag_AC3_1_0_1 = (149<<16) | 2, kAudioChannelLayoutTag_AC3_3_0 = (150<<16) | 3, kAudioChannelLayoutTag_AC3_3_1 = (151<<16) | 4, kAudioChannelLayoutTag_AC3_3_0_1 = (152<<16) | 4, kAudioChannelLayoutTag_AC3_2_1_1 = (153<<16) | 4, kAudioChannelLayoutTag_AC3_3_1_1 = (154<<16) | 5, kAudioChannelLayoutTag_EAC_6_0_A = (155<<16) | 6, kAudioChannelLayoutTag_EAC_7_0_A = (156<<16) | 7, kAudioChannelLayoutTag_EAC3_6_1_A = (157<<16) | 7, kAudioChannelLayoutTag_EAC3_6_1_B = (158<<16) | 7, kAudioChannelLayoutTag_EAC3_6_1_C = (159<<16) | 7, kAudioChannelLayoutTag_EAC3_7_1_A = (160<<16) | 8, kAudioChannelLayoutTag_EAC3_7_1_B = (161<<16) | 8, kAudioChannelLayoutTag_EAC3_7_1_C = (162<<16) | 8, kAudioChannelLayoutTag_EAC3_7_1_D = (163<<16) | 8, kAudioChannelLayoutTag_EAC3_7_1_E = (164<<16) | 8, kAudioChannelLayoutTag_EAC3_7_1_F = (165<<16) | 8, kAudioChannelLayoutTag_EAC3_7_1_G = (166<<16) | 8, kAudioChannelLayoutTag_EAC3_7_1_H = (167<<16) | 8, kAudioChannelLayoutTag_DTS_3_1 = (168<<16) | 4, kAudioChannelLayoutTag_DTS_4_1 = (169<<16) | 5, kAudioChannelLayoutTag_DTS_6_0_A = (170<<16) | 6, kAudioChannelLayoutTag_DTS_6_0_B = (171<<16) | 6, kAudioChannelLayoutTag_DTS_6_0_C = (172<<16) | 6, kAudioChannelLayoutTag_DTS_6_1_A = (173<<16) | 7, kAudioChannelLayoutTag_DTS_6_1_B = (174<<16) | 7, kAudioChannelLayoutTag_DTS_6_1_C = (175<<16) | 7, kAudioChannelLayoutTag_DTS_6_1_D = (182<<16) | 7, kAudioChannelLayoutTag_DTS_7_0 = (176<<16) | 7, kAudioChannelLayoutTag_DTS_7_1 = (177<<16) | 8, kAudioChannelLayoutTag_DTS_8_0_A = (178<<16) | 8, kAudioChannelLayoutTag_DTS_8_0_B = (179<<16) | 8, kAudioChannelLayoutTag_DTS_8_1_A = (180<<16) | 9, kAudioChannelLayoutTag_DTS_8_1_B = (181<<16) | 9, kAudioChannelLayoutTag_DiscreteInOrder = (147<<16) | 0 kAudioChannelLayoutTag_Unknown = 0xFFFF0000 };

    Constants

    • kAudioChannelLayoutTag_UseChannelDescriptions

      kAudioChannelLayoutTag_UseChannelDescriptions

      Use the array of AudioChannelDescription structures to define the layout.

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_UseChannelBitmap

      kAudioChannelLayoutTag_UseChannelBitmap

      Use the bitmap to define the layout.

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_Mono

      kAudioChannelLayoutTag_Mono

      A standard monophonic stream.

      Monophonic signal

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_Stereo

      kAudioChannelLayoutTag_Stereo

      A standard stereophonic stream; playback implied.

      Left

      Right

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_StereoHeadphones

      kAudioChannelLayoutTag_StereoHeadphones

      A standard stereo stream; headphone playback implied.

      Left

      Right

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MatrixStereo

      kAudioChannelLayoutTag_MatrixStereo

      A matrix-encoded stereo stream.

      Left matrix total

      Right matrix total

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MidSide

      kAudioChannelLayoutTag_MidSide

      Mid/side recording.

      Center

      Sides

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_XY

      kAudioChannelLayoutTag_XY

      Coincident, angled microphone pair.

      X (left)

      Y (right)

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_Binaural

      kAudioChannelLayoutTag_Binaural

      Binaural stereo.

      Left

      Right

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_Ambisonic_B_Format

      kAudioChannelLayoutTag_Ambisonic_B_Format

      Ambisonic B-format.

      W

      X

      Y

      Z

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_Quadraphonic

      kAudioChannelLayoutTag_Quadraphonic

      Quadraphonic, with 90° loudspeaker separation.

      Left front

      Right front

      Left back

      Right back

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_Pentagonal

      kAudioChannelLayoutTag_Pentagonal

      Pentagonal, with 72° loudspeaker separation.

      Left

      Right

      Left rear

      Right rear

      Center

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_Hexagonal

      kAudioChannelLayoutTag_Hexagonal

      Hexagonal, with 60° loudspeaker separation.

      Left

      Right

      Left rear

      Right rear

      Front center

      Rear center

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_Octagonal

      kAudioChannelLayoutTag_Octagonal

      Octagonal, with 45° loudspeaker separation.

      Left front

      Right front

      Left rear

      Right rear

      Center front

      Center rear

      Left side

      Right side

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_Cube

      kAudioChannelLayoutTag_Cube

      Cubic.

      Left front

      Right front

      Left rear

      Right rear

      Left front top

      Right front top

      Left rear top

      Right rear top

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_1_0

      kAudioChannelLayoutTag_MPEG_1_0

      MPEG 1-channel.

      Monophonic signal

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_2_0

      kAudioChannelLayoutTag_MPEG_2_0

      MPEG 2-channel.

      Left

      Right

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_3_0_A

      kAudioChannelLayoutTag_MPEG_3_0_A

      MPEG 3-channel layout A.

      Left

      Right

      Center

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_3_0_B

      kAudioChannelLayoutTag_MPEG_3_0_B

      MPEG 3-channel layout B.

      Center

      Left

      Right

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_4_0_A

      kAudioChannelLayoutTag_MPEG_4_0_A

      MPEG 4- channel layout A.

      Left

      Right

      Center

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_4_0_B

      kAudioChannelLayoutTag_MPEG_4_0_B

      MPEG 4-channel layout B.

      Center

      Left

      Right

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_5_0_A

      kAudioChannelLayoutTag_MPEG_5_0_A

      MPEG 5-channel layout A.

      Left

      Right

      Center

      Left surround

      Right surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_5_0_B

      kAudioChannelLayoutTag_MPEG_5_0_B

      MPEG 5-channel layout B.

      Left

      Right

      Left surround

      Right surround

      Center

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_5_0_C

      kAudioChannelLayoutTag_MPEG_5_0_C

      MPEG 5-channel layout C.

      Left

      Center

      Right

      Left surround

      Right surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_5_0_D

      kAudioChannelLayoutTag_MPEG_5_0_D

      MPEG 5-channel layout D.

      Center

      Left

      Right

      Left surround

      Right surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_5_1_A

      kAudioChannelLayoutTag_MPEG_5_1_A

      MPEG 5.1-channel layout A.

      Left

      Right

      Center

      Low-frequency effects

      Left surround

      Right surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_5_1_B

      kAudioChannelLayoutTag_MPEG_5_1_B

      MPEG 5.1-channel layout B.

      Left

      Right

      Left surround

      Right surround

      Center

      Low-frequency effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_5_1_C

      kAudioChannelLayoutTag_MPEG_5_1_C

      MPEG 5.1-channel layout C.

      Left

      Center

      Right

      Left surround

      Right surround

      Low-frequency effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_5_1_D

      kAudioChannelLayoutTag_MPEG_5_1_D

      MPEG 5.1-channel layout D.

      Center

      Left

      Right

      Left surround

      Right surround

      Low-frequency effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_6_1_A

      kAudioChannelLayoutTag_MPEG_6_1_A

      MPEG 6.1-channel layout A.

      Left

      Right

      Center

      Low-frequency effects

      Left surround

      Right surround

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_7_1_A

      kAudioChannelLayoutTag_MPEG_7_1_A

      MPEG 7.1-channel layout A.

      Left

      Right

      Center

      Low-frequency effects

      Left surround

      Right surround

      Left center

      Right center

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_7_1_B

      kAudioChannelLayoutTag_MPEG_7_1_B

      MPEG 7.1-channel layout A (see ISO/IEC 13818-7 MPEG2-AAC, Table 3.1).

      Center

      Left center

      Right center

      Left

      Right

      Left surround

      Right surround

      Low-frequency effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_MPEG_7_1_C

      kAudioChannelLayoutTag_MPEG_7_1_C

      MPEG 7.1-channel layout C.

      Left

      Right

      Center

      Low-frequency effects

      Left surround

      Right surround

      Left rear surround

      Right rear surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_Emagic_Default_7_1

      kAudioChannelLayoutTag_Emagic_Default_7_1

      Emagic 7.1-channel default layout.

      Left

      Right

      Left surround

      Right surround

      Center

      Low-frequency effects

      Left center

      Right center

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_SMPTE_DTV

      kAudioChannelLayoutTag_SMPTE_DTV

      SMPTE DTV layout; equivalent to the kAudioChannelLayoutTag_ITU_5_1 layout plus a matrix encoded stereo mix.

      Left

      Right

      Center

      Low-frequency effects

      Left surround

      Right surround

      Left matrix total

      Right matrix total

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_ITU_1_0

      kAudioChannelLayoutTag_ITU_1_0

      ITU 1-channel layout.

      Monophonic signal

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_ITU_2_0

      kAudioChannelLayoutTag_ITU_2_0

      ITU 2-channel layout.

      Left

      Right

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_ITU_2_1

      kAudioChannelLayoutTag_ITU_2_1

      ITU 2.1-channel layout.

      Left

      Right

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_ITU_2_2

      kAudioChannelLayoutTag_ITU_2_2

      ITU 2.2-channel layout.

      Left

      Right

      Left surround

      Right surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_ITU_3_0

      kAudioChannelLayoutTag_ITU_3_0

      ITU 3-channel layout.

      Left

      Right

      Center

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_ITU_3_1

      kAudioChannelLayoutTag_ITU_3_1

      ITU 3.1-channel layout.

      Left

      Right

      Center

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_ITU_3_2

      kAudioChannelLayoutTag_ITU_3_2

      ITU 3.2-channel layout.

      Left

      Right

      Center

      Left surround

      Right surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_ITU_3_2_1

      kAudioChannelLayoutTag_ITU_3_2_1

      ITU 3.2.1-channel layout.

      Left

      Right

      Center

      Low-frequency effects

      Left surround

      Right surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_ITU_3_4_1

      kAudioChannelLayoutTag_ITU_3_4_1

      ITU 3.4.1-channel layout.

      Left

      Right

      Center

      Low-frequency effects

      Left surround

      Right surround

      Left rear surround

      Right rear surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_0

      kAudioChannelLayoutTag_DVD_0

      DVD monaural layout.

      Monophonic signal

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_1

      kAudioChannelLayoutTag_DVD_1

      DVD stereo layout.

      Left

      Right

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_2

      kAudioChannelLayoutTag_DVD_2

      DVD 3-channel layout.

      Left

      Right

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_3

      kAudioChannelLayoutTag_DVD_3

      DVD 4-channel layout.

      Left

      Right

      Left surround

      Right surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_4

      kAudioChannelLayoutTag_DVD_4

      DVD 2.1-channel layout.

      Left

      Right

      Low-frequency effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_5

      kAudioChannelLayoutTag_DVD_5

      DVD 3.1-channel layout.

      Left

      Right

      Low-frequency effects

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_6

      kAudioChannelLayoutTag_DVD_6

      DVD 4.1-channel layout.

      Left

      Right

      Low-frequency effects

      Left surround

      Right surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_7

      kAudioChannelLayoutTag_DVD_7

      DVD 3-channel layout.

      Left

      Right

      Center

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_8

      kAudioChannelLayoutTag_DVD_8

      DVD 4-channel layout.

      Left

      Right

      Center

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_9

      kAudioChannelLayoutTag_DVD_9

      DVD 5-channel layout.

      Left

      Right

      Center

      Left surround

      Right surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_10

      kAudioChannelLayoutTag_DVD_10

      DVD 3.1-channel layout.

      Left

      Right

      Center

      Low-frequency effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_11

      kAudioChannelLayoutTag_DVD_11

      DVD 4.1-channel layout.

      Left

      Right

      Center

      Low-frequency effects

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_12

      kAudioChannelLayoutTag_DVD_12

      DVD 5.1-channel layout.

      Left

      Right

      Center

      Low-frequency effects

      Left surround

      Right surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_13

      kAudioChannelLayoutTag_DVD_13

      DVD 4-channel layout; equivalent to kAudioChannelLayoutTag_DVD_8.

      Left

      Right

      Center

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_14

      kAudioChannelLayoutTag_DVD_14

      DVD 5-channel layout; equivalent to kAudioChannelLayoutTag_DVD_9.

      Left

      Right

      Center

      Left surround

      Right surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_15

      kAudioChannelLayoutTag_DVD_15

      DVD 3.1-channel layout; equivalent to kAudioChannelLayoutTag_DVD_10.

      Left

      Right

      Center

      Low-frequency effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_16

      kAudioChannelLayoutTag_DVD_16

      DVD 4.1-channel layout; equivalent to kAudioChannelLayoutTag_DVD_11.

      Left

      Right

      Center

      Low-frequency effects

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_17

      kAudioChannelLayoutTag_DVD_17

      DVD 5.1-channel layout; equivalent to kAudioChannelLayoutTag_DVD_12.

      Left

      Right

      Center

      Low-frequency effects

      Left surround

      Right surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_18

      kAudioChannelLayoutTag_DVD_18

      DVD 4.1-channel layout.

      Left

      Right

      Left surround

      Right surround

      Low-frequency effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_19

      kAudioChannelLayoutTag_DVD_19

      DVD 5-channel layout.

      Left

      Right

      Left surround

      Right surround

      Center

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_DVD_20

      kAudioChannelLayoutTag_DVD_20

      DVD 5.1-channel layout.

      Left

      Right

      Left surround

      Right surround

      Center

      Low-frequency effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AudioUnit_4

      kAudioChannelLayoutTag_AudioUnit_4

      Quadraphonic symmetrical layout, recommended for use by audio units.

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AudioUnit_5

      kAudioChannelLayoutTag_AudioUnit_5

      Pentagonal symmetrical layout, recommended for use by audio units.

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AudioUnit_6

      kAudioChannelLayoutTag_AudioUnit_6

      Hexagonal symmetrical layout, recommended for use by audio units.

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AudioUnit_8

      kAudioChannelLayoutTag_AudioUnit_8

      Octagonal symmetrical layout, recommended for use by audio units.

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AudioUnit_5_0

      kAudioChannelLayoutTag_AudioUnit_5_0

      5-channel surround-based layout, recommended for use by audio units.

      Left

      Right

      Left surround

      Right surround

      Center

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AudioUnit_6_0

      kAudioChannelLayoutTag_AudioUnit_6_0

      6-channel surround-based layout, recommended for use by audio units.

      Left

      Right

      Left surround

      Right surround

      Center

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AudioUnit_7_0

      kAudioChannelLayoutTag_AudioUnit_7_0

      7-channel surround-based layout, recommended for use by audio units.

      Left

      Right

      Left surround

      Right surround

      Center

      Left rear surround

      Right rear surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AudioUnit_7_0_Front

      kAudioChannelLayoutTag_AudioUnit_7_0_Front

      Alternate 7-channel surround-based layout, for use by audio units.

      Left

      Right

      Left surround

      Right surround

      Center

      Left center

      Right center

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AudioUnit_5_1

      kAudioChannelLayoutTag_AudioUnit_5_1

      5.1-channel surround-based layout, recommended for use by audio units.

      Left

      Right

      Center

      Low-frequency effects

      Left surround

      Right surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AudioUnit_6_1

      kAudioChannelLayoutTag_AudioUnit_6_1

      6.1-channel surround-based layout, recommended for use by audio units.

      Left

      Right

      Center

      Low-frequency effects

      Left surround

      Right surround

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AudioUnit_7_1

      kAudioChannelLayoutTag_AudioUnit_7_1

      7.1-channel surround-based layout, recommended for use by audio units.

      Left

      Right

      Center

      Low-frequency effects

      Left surround

      Right surround

      Left rear surround

      Right rear surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AudioUnit_7_1_Front

      kAudioChannelLayoutTag_AudioUnit_7_1_Front

      7.1-channel surround-based layout, recommended for use by audio units.

      Left

      Right

      Center

      Low-frequency effects

      Left surround

      Right surround

      Left center

      Right center

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AAC_3_0

      kAudioChannelLayoutTag_AAC_3_0

      AAC 3-channel surround-based layout.

      Center

      Left

      Right

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AAC_Quadraphonic

      kAudioChannelLayoutTag_AAC_Quadraphonic

      AAC quadraphonic surround-based layout.

      Left

      Right

      Left surround

      Right surround

      Left surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AAC_4_0

      kAudioChannelLayoutTag_AAC_4_0

      AAC 4-channel surround-based layout.

      Center

      Left

      Right

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AAC_5_0

      kAudioChannelLayoutTag_AAC_5_0

      AAC 5-channel surround-based layout.

      Center

      Left

      Right

      Left surround

      Right surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AAC_5_1

      kAudioChannelLayoutTag_AAC_5_1

      AAC 5.1-channel surround-based layout.

      Center

      Left

      Right

      Left surround

      Right surround

      Low-frequency effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AAC_6_0

      kAudioChannelLayoutTag_AAC_6_0

      AAC 6-channel surround-based layout.

      Center

      Left

      Right

      Left surround

      Right surround

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AAC_6_1

      kAudioChannelLayoutTag_AAC_6_1

      AAC 6.1-channel surround-based layout.

      Center

      Left

      Right

      Left surround

      Right surround

      Center surround

      Low-frequency effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AAC_7_0

      kAudioChannelLayoutTag_AAC_7_0

      AAC 7-channel surround-based layout.

      Center

      Left

      Right

      Left surround

      Right surround

      Left rear surround

      Right rear surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AAC_7_1

      kAudioChannelLayoutTag_AAC_7_1

      AAC 7.1-channel surround-based layout.

      Center

      Left center

      Right center

      Left

      Right

      Left surround

      Right surround

      Low-frequency effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AAC_Octagonal

      kAudioChannelLayoutTag_AAC_Octagonal

      AAC 8-channel surround-based layout.

      Center

      Left

      Right

      Left surround

      Right surround

      Left rear surround

      Right rear surround

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_TMH_10_2_std

      kAudioChannelLayoutTag_TMH_10_2_std

      TMH 10.2, a multiple-channel surround-based layout .

      This table contains more than one row to accommodate the page width. There is no relationship between items in the same column.

      Left

      Right

      Center

      Vertical height center

      Left surround direct

      Right surround direct

      Left surround

      Right surround

      Vertical height left

      Vertical height right

      Left wide

      Right wide

      Center surround direct

      Center surround

      Low-frequency effects 1

      Low-frequency effects 2

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_TMH_10_2_full

      kAudioChannelLayoutTag_TMH_10_2_full

      TMH 10.2 (kAudioChannelLayoutTag_TMH_10_2_std) plus additional channels; recommended for use by audio units.

      This table contains more than one row to accommodate the page width. There is no relationship between items in the same column.

      Left

      Right

      Center

      Vertical height center

      Left surround direct

      Right surround direct

      Left surround

      Right surround

      Vertical height left

      Vertical height right

      Left wide

      Right wide

      Center surround direct

      Center surround

      Low-frequency effects 1

      Low-frequency effects 2

      Left center

      Right center

      HI

      VI

      Haptic

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AC3_1_0_1

      kAudioChannelLayoutTag_AC3_1_0_1

      An AC-3 layout.

      Center

      Low-frequency effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AC3_3_0

      kAudioChannelLayoutTag_AC3_3_0

      An AC-3 layout.

      Left

      Center

      Right

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AC3_3_1

      kAudioChannelLayoutTag_AC3_3_1

      An AC-3 layout.

      Left

      Center

      Right

      Center surround

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AC3_3_0_1

      kAudioChannelLayoutTag_AC3_3_0_1

      An AC-3 layout.

      Left

      Center

      Right

      Low-frequency effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AC3_2_1_1

      kAudioChannelLayoutTag_AC3_2_1_1

      An AC-3 layout.

      Left

      Right

      Center surround

      Low-frequency effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_AC3_3_1_1

      kAudioChannelLayoutTag_AC3_3_1_1

      An AC-3 layout.

      Left

      Center

      Right

      Center Surround

      Low-frequency Effects

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_EAC_6_0_A

      kAudioChannelLayoutTag_EAC_6_0_A

      A Blu-ray Disc audio layout for Enhanced AC-3, also known as Dolby Digital Plus.

      Left

      Center

      Right

      Left Surround

      Right Surround

      Center Surround

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_EAC_7_0_A

      kAudioChannelLayoutTag_EAC_7_0_A

      A Blu-ray Disc audio layout for Enhanced AC-3, also known as Dolby Digital Plus.

      Left

      Center

      Right

      Left Surround

      Right Surround

      Left rear surround

      Right rear surround

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_EAC3_6_1_A

      kAudioChannelLayoutTag_EAC3_6_1_A

      A Blu-ray Disc audio layout for Enhanced AC-3, also known as Dolby Digital Plus.

      Left

      Center

      Right

      Left Surround

      Right Surround

      Low-frequency effects

      Center surround

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_EAC3_6_1_B

      kAudioChannelLayoutTag_EAC3_6_1_B

      A Blu-ray Disc audio layout for Enhanced AC-3, also known as Dolby Digital Plus.

      Left

      Center

      Right

      Left Surround

      Right Surround

      Low-frequency effects

      Top surround

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_EAC3_6_1_C

      kAudioChannelLayoutTag_EAC3_6_1_C

      A Blu-ray Disc audio layout for Enhanced AC-3, also known as Dolby Digital Plus.

      Left

      Center

      Right

      Left Surround

      Right Surround

      Low-frequency effects

      Vertical height center

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_EAC3_7_1_A

      kAudioChannelLayoutTag_EAC3_7_1_A

      A Blu-ray Disc audio layout for Enhanced AC-3, also known as Dolby Digital Plus.

      Left

      Center

      Right

      Left Surround

      Right Surround

      Low-frequency effects

      Left rear surround

      Right rear surround

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_EAC3_7_1_B

      kAudioChannelLayoutTag_EAC3_7_1_B

      A Blu-ray Disc audio layout for Enhanced AC-3, also known as Dolby Digital Plus.

      Left

      Center

      Right

      Left Surround

      Right Surround

      Low-frequency effects

      Left center

      Right center

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_EAC3_7_1_C

      kAudioChannelLayoutTag_EAC3_7_1_C

      A Blu-ray Disc audio layout for Enhanced AC-3, also known as Dolby Digital Plus.

      Left

      Center

      Right

      Left Surround

      Right Surround

      Low-frequency effects

      Left surround direct

      Right surround direct

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_EAC3_7_1_D

      kAudioChannelLayoutTag_EAC3_7_1_D

      A Blu-ray Disc audio layout for Enhanced AC-3, also known as Dolby Digital Plus.

      Left

      Center

      Right

      Left Surround

      Right Surround

      Low-frequency effects

      Left wide

      Right wide

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_EAC3_7_1_E

      kAudioChannelLayoutTag_EAC3_7_1_E

      A Blu-ray Disc audio layout for Enhanced AC-3, also known as Dolby Digital Plus.

      Left

      Center

      Right

      Left Surround

      Right Surround

      Low-frequency effects

      Vertical height left

      Vertical height right

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_EAC3_7_1_F

      kAudioChannelLayoutTag_EAC3_7_1_F

      A Blu-ray Disc audio layout for Enhanced AC-3, also known as Dolby Digital Plus.

      Left

      Center

      Right

      Left Surround

      Right Surround

      Low-frequency effects

      Center surround

      Top surround

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_EAC3_7_1_G

      kAudioChannelLayoutTag_EAC3_7_1_G

      A Blu-ray Disc audio layout for Enhanced AC-3, also known as Dolby Digital Plus.

      Left

      Center

      Right

      Left Surround

      Right Surround

      Low-frequency effects

      Center surround

      Vertical height center

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_EAC3_7_1_H

      kAudioChannelLayoutTag_EAC3_7_1_H

      A Blu-ray Disc audio layout for Enhanced AC-3, also known as Dolby Digital Plus.

      Left

      Center

      Right

      Left Surround

      Right Surround

      Low-frequency effects

      Top surround

      Vertical height center

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DTS_3_1

      kAudioChannelLayoutTag_DTS_3_1

      A Blu-ray Disc audio layout, defined by DTS (Digital Theater Systems Ltd.).

      Center

      Left

      Right

      Low-frequency effects

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DTS_4_1

      kAudioChannelLayoutTag_DTS_4_1

      A Blu-ray Disc audio layout, defined by DTS (Digital Theater Systems Ltd.).

      Center

      Left

      Right

      Center surround

      Low-frequency effects

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DTS_6_0_A

      kAudioChannelLayoutTag_DTS_6_0_A

      A Blu-ray Disc audio layout, defined by DTS (Digital Theater Systems Ltd.).

      Left center

      Right center

      Left

      Right

      Left surround

      Right surround

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DTS_6_0_B

      kAudioChannelLayoutTag_DTS_6_0_B

      A Blu-ray Disc audio layout, defined by DTS (Digital Theater Systems Ltd.).

      Center

      Left

      Right

      Left rear surround

      Right rear surround

      Top surround

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DTS_6_0_C

      kAudioChannelLayoutTag_DTS_6_0_C

      A Blu-ray Disc audio layout, defined by DTS (Digital Theater Systems Ltd.).

      Center

      Center surround

      Left

      Right

      Left rear surround

      Right rear surround

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DTS_6_1_A

      kAudioChannelLayoutTag_DTS_6_1_A

      A Blu-ray Disc audio layout, defined by DTS (Digital Theater Systems Ltd.).

      Left center

      Right center

      Left

      Right

      Left surround

      Right surround

      Low-frequency effects

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DTS_6_1_B

      kAudioChannelLayoutTag_DTS_6_1_B

      A Blu-ray Disc audio layout, defined by DTS (Digital Theater Systems Ltd.).

      Center

      Left

      Right

      Left rear surround

      Right rear surround

      Top surround

      Low-frequency effects

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DTS_6_1_C

      kAudioChannelLayoutTag_DTS_6_1_C

      A Blu-ray Disc audio layout, defined by DTS (Digital Theater Systems Ltd.).

      Center

      Center surround

      Left

      Right

      Left rear surround

      Right rear surround

      Low-frequency effects

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DTS_6_1_D

      kAudioChannelLayoutTag_DTS_6_1_D

      A Blu-ray Disc audio layout, defined by DTS (Digital Theater Systems Ltd.).

      Center

      Left

      Right

      Left surround

      Right surround

      Low-frequency effects

      Center surround

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DTS_7_0

      kAudioChannelLayoutTag_DTS_7_0

      A Blu-ray Disc audio layout, defined by DTS (Digital Theater Systems Ltd.).

      Left center

      Center

      Right center

      Left

      Right

      Left surround

      Right surround

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DTS_7_1

      kAudioChannelLayoutTag_DTS_7_1

      A Blu-ray Disc audio layout, defined by DTS (Digital Theater Systems Ltd.).

      Left center

      Center

      Right center

      Left

      Right

      Left surround

      Right surround

      Low-frequency effects

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DTS_8_0_A

      kAudioChannelLayoutTag_DTS_8_0_A

      A Blu-ray Disc audio layout, defined by DTS (Digital Theater Systems Ltd.).

      Left center

      Right center

      Left

      Right

      Left surround

      Right surround

      Left rear surround

      Right rear surround

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DTS_8_0_B

      kAudioChannelLayoutTag_DTS_8_0_B

      A Blu-ray Disc audio layout, defined by DTS (Digital Theater Systems Ltd.).

      Left center

      Center

      Right

      Left

      Right

      Left surround

      Center surround

      Right surround

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DTS_8_1_A

      kAudioChannelLayoutTag_DTS_8_1_A

      A Blu-ray Disc audio layout, defined by DTS (Digital Theater Systems Ltd.).

      Left center

      Right center

      Left

      Right

      Left surround

      Right surround

      Left rear surround

      Right rear surround

      Low-frequency effects

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DTS_8_1_B

      kAudioChannelLayoutTag_DTS_8_1_B

      A Blu-ray Disc audio layout, defined by DTS (Digital Theater Systems Ltd.).

      Left center

      Center

      Right center

      Left

      Right

      Left surround

      Center surround

      Right surround

      Low-frequency effects

      Available in iOS 4.0 and later

    • kAudioChannelLayoutTag_DiscreteInOrder

      kAudioChannelLayoutTag_DiscreteInOrder

      Needs to be ORed with the actual number of channels.

      Available in iOS 2.0 and later

    • kAudioChannelLayoutTag_Unknown

      kAudioChannelLayoutTag_Unknown

      Needs to be ORed with the actual number of channels.

      Available in iOS 2.0 and later

Result Codes

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

  • An unimplemented system function was called.

    Value

    -4

    Description

    An unimplemented system function was called.

    Available in iOS 4.0 and later.

  • The file was not found.

    Value

    -43

    Description

    The file was not found.

    Available in iOS 4.3 and later.

  • An error in the parameter list of the function.

    Value

    -50

    Description

    An error in the parameter list of the function.

    Available in iOS 4.0 and later.

  • Not enough room in the heap zone.

    Value

    -108

    Description

    Not enough room in the heap zone.

    Available in iOS 4.0 and later.