---
title: magicCookie
framework: avfaudio
role: symbol
role_heading: Instance Property
path: avfaudio/avaudioformat/magiccookie
---

# magicCookie

An object that contains metadata that encoders and decoders require.

## Declaration

```swift
var magicCookie: Data? { get set }
```

## Discussion

Discussion Encoders produce a magicCookie object, and some decoders require it to decode properly.

## See Also

### Determining the Audio Format

- [isInterleaved](avfaudio/avaudioformat/isinterleaved.md)
- [isStandard](avfaudio/avaudioformat/isstandard.md)
- [commonFormat](avfaudio/avaudioformat/commonformat.md)
- [settings](avfaudio/avaudioformat/settings.md)