---
title: mFormatID
framework: audiotoolbox
role: symbol
role_heading: Instance Property
path: audiotoolbox/audiofiletypeandformatid/mformatid
---

# mFormatID

A four-character code for the format ID such as kAudioFormatLinearPCM, kAudioFormatMPEG4AAC, and so forth. (See the AudioFormat.h header file for declarations.)

## Declaration

```swift
var mFormatID: UInt32
```