Audio Data Format Identifiers

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

Overview

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.

Topics

Constants

var kAudioFormatAC3: AudioFormatID

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

var kAudioFormat60958AC3: AudioFormatID

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.

var kAudioFormatAppleIMA4: AudioFormatID

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

var kAudioFormatMPEG4AAC: AudioFormatID

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.

var kAudioFormatMPEG4CELP: AudioFormatID

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.

var kAudioFormatMPEG4HVXC: AudioFormatID

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.

var kAudioFormatMPEG4TwinVQ: AudioFormatID

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.

var kAudioFormatMACE3: AudioFormatID

MACE 3:1. Uses no flags.

var kAudioFormatMACE6: AudioFormatID

MACE 6:1. Uses no flags.

var kAudioFormatULaw: AudioFormatID

μLaw 2:1. Uses no flags.

var kAudioFormatALaw: AudioFormatID

aLaw 2:1. Uses no flags.

var kAudioFormatQDesign: AudioFormatID

QDesign music. Uses no flags

var kAudioFormatQDesign2: AudioFormatID

QDesign2 music. Uses no flags

var kAudioFormatQUALCOMM: AudioFormatID

QUALCOMM PureVoice. Uses no flags

var kAudioFormatMPEGLayer1: AudioFormatID

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

var kAudioFormatMPEGLayer2: AudioFormatID

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

var kAudioFormatMPEGLayer3: AudioFormatID

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

var kAudioFormatTimeCode: AudioFormatID

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

var kAudioFormatMIDIStream: AudioFormatID

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.

var kAudioFormatParameterValueStream: AudioFormatID

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.

var kAudioFormatAppleLossless: AudioFormatID

Apple Lossless. Uses no flags.

var kAudioFormatMPEG4AAC_HE: AudioFormatID

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

var kAudioFormatMPEG4AAC_LD: AudioFormatID

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

var kAudioFormatMPEG4AAC_ELD: AudioFormatID

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

var kAudioFormatMPEG4AAC_ELD_SBR: AudioFormatID

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

var kAudioFormatMPEG4AAC_HE_V2: AudioFormatID

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

var kAudioFormatMPEG4AAC_Spatial: AudioFormatID

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

var kAudioFormatAMR: AudioFormatID

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

var kAudioFormatAudible: AudioFormatID

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

var kAudioFormatiLBC: AudioFormatID

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

var kAudioFormatDVIIntelIMA: AudioFormatID

DVI/Intel IMA ADPCM - ACM code 17.

var kAudioFormatMicrosoftGSM: AudioFormatID

Microsoft GSM 6.10 - ACM code 49.

var kAudioFormatAES3: AudioFormatID

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.

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