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# AudioChannelLayout

A structure that specifies a channel layout in a file or in hardware.

```
struct AudioChannelLayout
```

## Topics

### Accessing the Data

[`mChannelBitmap`](/documentation/CoreAudioTypes/AudioChannelLayout/mChannelBitmap)

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

[`AudioChannelBitmap`](/documentation/CoreAudioTypes/AudioChannelBitmap)

The supported channel bitmaps to use when defining channel layouts.

[`mChannelDescriptions`](/documentation/CoreAudioTypes/AudioChannelLayout/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.

[`mChannelLayoutTag`](/documentation/CoreAudioTypes/AudioChannelLayout/mChannelLayoutTag)

The `AudioChannelLayoutTag` value that indicates the layout. See [Audio Channel Layout Tags](/documentation/CoreAudioTypes/audio-channel-layout-tags) for possible values.

[`AudioChannelLayoutTag`](/documentation/CoreAudioTypes/AudioChannelLayoutTag)

Identifies a previously-defined channel layout.

[Audio Channel Layout Tags](/documentation/CoreAudioTypes/audio-channel-layout-tags)

The identifiers that represent audio channel layouts.

[`mNumberChannelDescriptions`](/documentation/CoreAudioTypes/AudioChannelLayout/mNumberChannelDescriptions)

The number of items in the `mChannelDescriptions` array.

[`AudioChannelLayoutTag_GetNumberOfChannels`](/documentation/CoreAudioTypes/AudioChannelLayoutTag_GetNumberOfChannels(_:))

Retrieves the number of channels from an audio channel layout tag.

### Accessing the Data

[`mChannelBitmap`](/documentation/CoreAudioTypes/AudioChannelLayout/mChannelBitmap)

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

[`AudioChannelBitmap`](/documentation/CoreAudioTypes/AudioChannelBitmap)

The supported channel bitmaps to use when defining channel layouts.

[`mChannelDescriptions`](/documentation/CoreAudioTypes/AudioChannelLayout/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.

[`mChannelLayoutTag`](/documentation/CoreAudioTypes/AudioChannelLayout/mChannelLayoutTag)

The `AudioChannelLayoutTag` value that indicates the layout. See [Audio Channel Layout Tags](/documentation/CoreAudioTypes/audio-channel-layout-tags) for possible values.

[`AudioChannelLayoutTag`](/documentation/CoreAudioTypes/AudioChannelLayoutTag)

Identifies a previously-defined channel layout.

[`mNumberChannelDescriptions`](/documentation/CoreAudioTypes/AudioChannelLayout/mNumberChannelDescriptions)

The number of items in the `mChannelDescriptions` array.

[`AudioChannelLayoutTag_GetNumberOfChannels`](/documentation/CoreAudioTypes/AudioChannelLayoutTag_GetNumberOfChannels(_:))

Retrieves the number of channels from an audio channel layout tag.

### Initializers

[`init()`](/documentation/CoreAudioTypes/AudioChannelLayout/init())

[`init(mChannelLayoutTag:mChannelBitmap:mNumberChannelDescriptions:mChannelDescriptions:)`](/documentation/CoreAudioTypes/AudioChannelLayout/init(mChannelLayoutTag:mChannelBitmap:mNumberChannelDescriptions:mChannelDescriptions:))

## Relationships

### Conforms To

[`Sendable`](/documentation/Swift/Sendable)

[`BitwiseCopyable`](/documentation/Swift/BitwiseCopyable)

---

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