---
title: mClassDescription
framework: audiotoolbox
role: symbol
role_heading: Instance Property
path: audiotoolbox/extendedaudioformatinfo/mclassdescription
---

# mClassDescription

A structure that describes an audio codec.

## Declaration

```swift
var mClassDescription: AudioClassDescription
```

## Discussion

Discussion An AudioClassDescription struct that specifies the codec to be used.