<!--
{
  "availability" : [
    "iOS: 15.0.0 -",
    "iPadOS: 15.0.0 -",
    "macCatalyst: 15.0.0 -",
    "macOS: 12.0.0 -",
    "tvOS: 17.0.0 -",
    "visionOS: 1.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "PHASE",
  "identifier" : "/documentation/PHASE/PHASENumberMetaParameter",
  "metadataVersion" : "0.1.0",
  "role" : "Class",
  "symbol" : {
    "kind" : "Class",
    "modules" : [
      "PHASE"
    ],
    "preciseIdentifier" : "c:objc(cs)PHASENumberMetaParameter"
  },
  "title" : "PHASENumberMetaParameter"
}
-->

# PHASENumberMetaParameter

A metaparameter defined by a number that can change over time.

```
class PHASENumberMetaParameter
```

## Overview

This class contains a number that updates, like a “player speed” metaparameter that the app changes gradually from `0.0` to `1.0`.

To create an instance of this class, first create a [`PHASENumberMetaParameterDefinition`](/documentation/PHASE/PHASENumberMetaParameterDefinition), and either:

- Register it with the engine by calling [`registerGlobalMetaParameter(metaParameterDefinition:)`](/documentation/PHASE/PHASEAssetRegistry/registerGlobalMetaParameter(metaParameterDefinition:)), then access the instance of this class in the engine’s [`globalMetaParameters`](/documentation/PHASE/PHASEAssetRegistry/globalMetaParameters) dictionary.
- Pass it to the [`PHASEBlendNodeDefinition`](/documentation/PHASE/PHASEBlendNodeDefinition) initializer, [`init(blendMetaParameterDefinition:identifier:)`](/documentation/PHASE/PHASEBlendNodeDefinition/init(blendMetaParameterDefinition:identifier:)), and then access the instance of this class in a sound event’s [`metaParameters`](/documentation/PHASE/PHASESoundEvent/metaParameters) dictionary.
- Use it as the input value for a [`PHASEMappedMetaParameterDefinition`](/documentation/PHASE/PHASEMappedMetaParameterDefinition) by passing it into the [`init(inputMetaParameterDefinition:envelope:)`](/documentation/PHASE/PHASEMappedMetaParameterDefinition/init(inputMetaParameterDefinition:envelope:)) initializer. Then, access the instance of this class using the mapped parameter’s [`inputMetaParameterDefinition`](/documentation/PHASE/PHASEMappedMetaParameterDefinition/inputMetaParameterDefinition) property.

## Topics

### Inspecting Extremes

[`minimum`](/documentation/PHASE/PHASENumberMetaParameter/minimum)

The lowest possible number for the value.

[`maximum`](/documentation/PHASE/PHASENumberMetaParameter/maximum)

The highest possible number for the value.

### Interpolating the Value

[`-  fadeToValue:duration:`](/documentation/PHASE/PHASENumberMetaParameter/fade(value:duration:))

Sets the value gradually over the given amount of time.

## Relationships

### Conforms To

[`NSObjectProtocol`](/documentation/ObjectiveC/NSObjectProtocol)

[`CustomDebugStringConvertible`](/documentation/Swift/CustomDebugStringConvertible)

[`Hashable`](/documentation/Swift/Hashable)

[`CustomStringConvertible`](/documentation/Swift/CustomStringConvertible)

[`Equatable`](/documentation/Swift/Equatable)

[`CVarArg`](/documentation/Swift/CVarArg)

### Inherits From

[`PHASEMetaParameter`](/documentation/PHASE/PHASEMetaParameter)

---

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)