---
title: "init(base:)"
framework: coremedia
role: symbol
role_heading: Initializer
path: "coremedia/cmformatdescription/extensions-swift.struct/init(base:)"
---

# init(base:)

Creates an Extensions structure with existing values.

## Declaration

```swift
init(base: [CFString : CFPropertyList]?)
```

## See Also

### Creating Extensions

- [init()](coremedia/cmformatdescription/extensions-swift.struct/init().md)