# CMAudioFormatDescriptionGetFormatList(_:sizeOut:) Returns a read-only pointer to, and size of, the array of audio format list item structures in an audio format description. ``` func CMAudioFormatDescriptionGetFormatList(_ desc: CMAudioFormatDescription, sizeOut: UnsafeMutablePointer?) -> UnsafePointer? ``` ## Parameters `desc` `CMFormatDescription` being interrogated. `sizeOut` Pointer to variable that will be written with the size of the `formatList`. ## Return Value A read-only pointer to the array of `AudioFormatListItem` structs inside the audio format description. ## Discussion This property is analogous to `kAudioFormatProperty_FormatList` and follows its conventions. Namely, the API returns formats in order from the most to least useful, with channel count taking the highest precedence followed by sample rate. This API is specific to audio format descriptions, and returns `NULL` if called with a non-audio format description. --- Copyright © 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)