<!--
{
  "availability" : [
    "iOS: 9.0.0 -",
    "iPadOS: 9.0.0 -",
    "macCatalyst: 14.0.0 -",
    "tvOS: 17.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "AVFoundation",
  "identifier" : "/documentation/AVFoundation/AVCaptureMetadataInput/init(formatDescription:clock:)",
  "metadataVersion" : "0.1.0",
  "role" : "Initializer",
  "symbol" : {
    "kind" : "Initializer",
    "modules" : [
      "AVFoundation"
    ],
    "preciseIdentifier" : "c:objc(cs)AVCaptureMetadataInput(im)initWithFormatDescription:clock:"
  },
  "title" : "init(formatDescription:clock:)"
}
-->

# init(formatDescription:clock:)

Creates capture metadata input to provide timed groups to a capture session.

```
init(formatDescription desc: CMMetadataFormatDescription, clock: CMClock)
```

## Parameters

`desc`

A <doc://com.apple.documentation/documentation/CoreMedia/CMFormatDescription> that defines the metadata to be supplied by the client. Throws <doc://com.apple.documentation/documentation/Foundation/NSExceptionName/invalidArgumentException> if `NULL` is passed.

`clock`

A <doc://com.apple.documentation/documentation/CoreMedia/CMClock> that provides the timebase for the supplied samples. Throws <doc://com.apple.documentation/documentation/Foundation/NSExceptionName/invalidArgumentException> if `NULL` is passed.

---

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)