---
title: kCMTimeRangeDurationKey
framework: Core Media
role: symbol
role_heading: Global Variable
platforms: [iOS 4.0+, iPadOS 4.0+, Mac Catalyst 13.1+, macOS 10.7+, tvOS 9.0+, visionOS 1.0+, watchOS 6.0+]
path: coremedia/kcmtimerangedurationkey
---

# kCMTimeRangeDurationKey

The key for the timescale of a time range.

## Declaration

```swift
let kCMTimeRangeDurationKey: CFString
```

## See Also

### Constants

- [kCMTimeRangeStartKey](coremedia/kcmtimerangestartkey.md)