---
title: rdd18UserItems
framework: AVFoundation
role: symbol
role_heading: Type Property
platforms: [iOS 27.0+, iPadOS 27.0+, Mac Catalyst 27.0+, macOS 27.0+, tvOS 27.0+]
path: avfoundation/avcaptureancillarydatauserkey/rdd18useritems
---

# rdd18UserItems

An AVCaptureAncillaryDataEncoder key corresponding with RDD18 user defined metadata

## Declaration

```swift
static let rdd18UserItems: AVCaptureAncillaryDataUserKey
```

## Discussion

Discussion Clients may inspect the user metadata with AVCaptureAncillaryDataEncoder\currentUserDefinedAncillaryData and set it with AVCaptureAncillaryDataEncoder\setRDD18AncillaryData:forTag:error: AVCaptureAncillaryDataEncoder\setRDD18AncillaryDataString:forTag:error: or remove it with AVCaptureAncillaryDataEncoder\removeRDD18AncillaryDataForTag: