<!--
{
  "availability" : [

  ],
  "documentType" : "symbol",
  "framework" : "QuickTime File Format",
  "identifier" : "/documentation/quicktime-file-format/Audio_channel_layout_atom",
  "metadataVersion" : "0.1.0",
  "role" : "Atom",
  "symbol" : {
    "kind" : "Atom",
    "modules" : [
      "QuickTime File Format"
    ],
    "preciseIdentifier" : "__docc_universal_symbol_reference_$Audio_channel_layout_atom"
  },
  "title" : "Audio channel layout atom ('chan')"
}
-->

# Audio channel layout atom ('chan')

An optional extension to the sound sample description specifying audio channel layouts for sound media contained in QuickTime movies.

## Overview

This atom is an optional extension to the sound sample description specifying audio channel layouts for sound media contained in QuickTime movies. It is a full atom followed by a big-endian audio channel layout structure as defined by Apple’s Core Audio framework. Audio channel layouts can be applied to both compressed and uncompressed sound formats.

> Note: Audio channel layouts with more than two channels per track require implementation with a version 2 sound sample description.

## Topics

### Data fields

[`Size`](/documentation/quicktime-file-format/Audio_channel_layout_atom/Size)

An unsigned 32-bit integer holding the size of the audio channel layout atom.

[`Type`](/documentation/quicktime-file-format/Audio_channel_layout_atom/Type)

An unsigned 32-bit field.

[`Version`](/documentation/quicktime-file-format/Audio_channel_layout_atom/Version)

A 1-byte specification of the version of the audio channel layout atom.

[`Flags`](/documentation/quicktime-file-format/Audio_channel_layout_atom/Flags)

A 3-byte space for audio channel layout flags.

[`Audio channel layout`](/documentation/quicktime-file-format/Audio_channel_layout_atom/Audio_channel_layout)

An audio channel layout structure.


---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)