<!--
{
  "availability" : [
    "iOS: -",
    "iPadOS: -",
    "macCatalyst: -",
    "macOS: -",
    "tvOS: -",
    "visionOS: -",
    "watchOS: -"
  ],
  "documentType" : "symbol",
  "framework" : "AVFoundation",
  "identifier" : "/documentation/AVFoundation/AVMetadataItem/commonKey",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Property",
  "symbol" : {
    "kind" : "Instance Property",
    "modules" : [
      "AVFoundation"
    ],
    "preciseIdentifier" : "c:objc(cs)AVMetadataItem(py)commonKey"
  },
  "title" : "commonKey"
}
-->

# commonKey

The common key of the metadata item.

```
var commonKey: AVMetadataKey? { get }
```

## Discussion

This value contains the key that most closely corresponds to the [`key`](/documentation/AVFoundation/AVMetadataItem/key) property, but that belongs to the common key space. You can use this key to locate metadata items irrespective of the underlying media format.

If the value of the [`keySpace`](/documentation/AVFoundation/AVMetadataItem/keySpace) property is [`common`](/documentation/AVFoundation/AVMetadataKeySpace/common), this property value contains the same key as the [`key`](/documentation/AVFoundation/AVMetadataItem/key) property.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)