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# AVAssetReaderOutputCaptionAdaptor

An object that reads caption group objects from an asset track that contains timed text.

```
class AVAssetReaderOutputCaptionAdaptor
```

## Topics

### Creating a caption adaptor

[`-  initWithAssetReaderTrackOutput:`](/documentation/AVFoundation/AVAssetReaderOutputCaptionAdaptor/init(assetReaderTrackOutput:))

Creates a caption adaptor that reads from a track output.

[`+  assetReaderOutputCaptionAdaptorWithAssetReaderTrackOutput:`](/documentation/AVFoundation/AVAssetReaderOutputCaptionAdaptor/assetReaderOutputCaptionAdaptorWithAssetReaderTrackOutput:)

A class method that creates a caption adaptor that reads from a track output.

### Accessing the track output

[`assetReaderTrackOutput`](/documentation/AVFoundation/AVAssetReaderOutputCaptionAdaptor/assetReaderTrackOutput)

The associated asset reader track output.

### Managing the validation delegate

[`validationDelegate`](/documentation/AVFoundation/AVAssetReaderOutputCaptionAdaptor/validationDelegate)

A delegate object that handles callbacks to the caption adaptor.

[`AVAssetReaderCaptionValidationHandling`](/documentation/AVFoundation/AVAssetReaderCaptionValidationHandling)

A protocol that defines the methods for caption validation events.

### Reading caption groups

[`-  nextCaptionGroup`](/documentation/AVFoundation/AVAssetReaderOutputCaptionAdaptor/nextCaptionGroup())

Returns the next caption group.

[`-  captionsNotPresentInPreviousGroupsInCaptionGroup:`](/documentation/AVFoundation/AVAssetReaderOutputCaptionAdaptor/captionsNotPresentInPreviousGroups(in:))

Returns the set of captions in the caption group that weren’t vended by the adaptor.

## Relationships

### Inherits From

[`NSObject-swift.class`](/documentation/ObjectiveC/NSObject-swift.class)

### Conforms To

[`NSObjectProtocol`](/documentation/ObjectiveC/NSObjectProtocol)

[`CustomDebugStringConvertible`](/documentation/Swift/CustomDebugStringConvertible)

[`Equatable`](/documentation/Swift/Equatable)

[`Hashable`](/documentation/Swift/Hashable)

[`CVarArg`](/documentation/Swift/CVarArg)

[`CustomStringConvertible`](/documentation/Swift/CustomStringConvertible)

---

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