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# AVMutableCaptionRegion

A mutable caption region subclass that you use to create new caption regions.

```
class AVMutableCaptionRegion
```

## Topics

### Creating a caption region

[`init()`](/documentation/AVFoundation/AVMutableCaptionRegion/init())

Creates a caption region.

[`init(identifier:)`](/documentation/AVFoundation/AVMutableCaptionRegion/init(identifier:))

Creates a caption region that has an identifier.

### Configuring the region

[`origin`](/documentation/AVFoundation/AVMutableCaptionRegion/origin)

The region’s top-left position.

[`size`](/documentation/AVFoundation/AVMutableCaptionRegion/size)

The height and width of the region.

[`displayAlignment`](/documentation/AVFoundation/AVMutableCaptionRegion/displayAlignment)

The alignment of lines for the region.

[`scroll`](/documentation/AVFoundation/AVMutableCaptionRegion/scroll)

The scroll mode of the region.

[`writingMode`](/documentation/AVFoundation/AVMutableCaptionRegion/writingMode)

The block and inline progression direction of the region.


---

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