---
title: "CMTimeMappingCopyDescription(allocator:mapping:)"
framework: Core Media
role: symbol
role_heading: Function
platforms: [iOS 9.0+, iPadOS 9.0+, Mac Catalyst 13.1+, macOS 10.11+, tvOS 9.0+, visionOS 1.0+, watchOS 6.0+]
path: "coremedia/cmtimemappingcopydescription(allocator:mapping:)"
---

# CMTimeMappingCopyDescription(allocator:mapping:)

Copies a string description of a time mapping.

## Declaration

```swift
func CMTimeMappingCopyDescription(allocator: CFAllocator?, mapping: CMTimeMapping) -> CFString?
```

## Parameters

- `allocator`: An allocator to use to create a dictionary. Pass kCFAllocatorDefault to use the default allocator.
- `mapping`: The time mapping from which to copy a description.

## Return Value

Return Value A string description of a time mapping.

## See Also

### Representing Time Mappings

- [CMTimeMappingCopyAsDictionary(_:allocator:)](coremedia/cmtimemappingcopyasdictionary(_:allocator:).md)
- [CMTimeMappingShow(_:)](coremedia/cmtimemappingshow(_:).md)