---
title: logTransferFunction
framework: coremedia
role: symbol
role_heading: Type Property
path: coremedia/cmformatdescription/extensions-swift.struct/key/logtransferfunction
---

# logTransferFunction

Indicates that the transfer function or gamma of the content is a log format and identifies the specific log curve.

## Declaration

```swift
@backDeployed(before: macOS 26.0, iOS 26.0, tvOS 26.0, watchOS 26.0, visionOS 26.0)
static var logTransferFunction: CMFormatDescription.Extensions.Key { get }
```