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# AVMetadataExtraAttributeKey

A structure that defines keys for extra metadata attributes.

```
struct AVMetadataExtraAttributeKey
```

## Topics

### Extra attribute keys

[`valueURI`](/documentation/AVFoundation/AVMetadataExtraAttributeKey/valueURI)

A key that identifies a resource to use as the item’s value.

[`baseURI`](/documentation/AVFoundation/AVMetadataExtraAttributeKey/baseURI)

A key that identifies the base URI the item uses to resolve its related URIs.

[`info`](/documentation/AVFoundation/AVMetadataExtraAttributeKey/info)

A key that identifies more information about the item.

### Initializers

[`init(_:)`](/documentation/AVFoundation/AVMetadataExtraAttributeKey/init(_:))

Creates an extra attribute key with a string.

[`init(rawValue:)`](/documentation/AVFoundation/AVMetadataExtraAttributeKey/init(rawValue:))

Creates an extra attribute key with a raw string value.


---

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