<!--
{
  "availability" : [
    "iOS: -",
    "iPadOS: -",
    "macCatalyst: -",
    "macOS: -",
    "tvOS: -",
    "visionOS: -",
    "watchOS: -"
  ],
  "documentType" : "symbol",
  "framework" : "Accelerate",
  "identifier" : "/documentation/Accelerate/vImageChannelDescription",
  "metadataVersion" : "0.1.0",
  "role" : "Structure",
  "symbol" : {
    "kind" : "Structure",
    "modules" : [
      "Accelerate"
    ],
    "preciseIdentifier" : "c:@S@vImageChannelDescription"
  },
  "title" : "vImageChannelDescription"
}
-->

# vImageChannelDescription

A description of the range and clamp limits for a pixel format.

```
struct vImageChannelDescription
```

## Overview

A [`vImageChannelDescription`](/documentation/Accelerate/vImageChannelDescription) structure describes the range and clamp limits for each channel in a Core Video image format. The [`min`](/documentation/Accelerate/vImageChannelDescription/min) and [`max`](/documentation/Accelerate/vImageChannelDescription/max) properties define the clamping limits, and functions clamp values to [`min`](/documentation/Accelerate/vImageChannelDescription/min)…[`max`](/documentation/Accelerate/vImageChannelDescription/max). The [`zero`](/documentation/Accelerate/vImageChannelDescription/zero) and [`full`](/documentation/Accelerate/vImageChannelDescription/full) values specify the normal range and bias for a format, and encode `0.0` and `1.0`, respectively (`0.0` and `0.5` for chrominance).

## Topics

### Creating a channel description

[`init(min:zero:full:max:)`](/documentation/Accelerate/vImageChannelDescription/init(min:zero:full:max:))

Returns a structure that describes the range and clamp limits for a pixel format.

[`init()`](/documentation/Accelerate/vImageChannelDescription/init())

Returns an empty structure that describes the range and clamp limits for a pixel format.

### Instance properties

[`min`](/documentation/Accelerate/vImageChannelDescription/min)

The minimum encoded value.

[`zero`](/documentation/Accelerate/vImageChannelDescription/zero)

The encoding for the value zero.

[`full`](/documentation/Accelerate/vImageChannelDescription/full)

The encoding for the value one.

[`max`](/documentation/Accelerate/vImageChannelDescription/max)

The maximum encoded value.


---

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)