---
title: AVParameterEvent
framework: avfaudio
role: symbol
role_heading: Class
path: avfaudio/avparameterevent
---

# AVParameterEvent

An object that represents a parameter event on a music track’s destination.

## Declaration

```swift
class AVParameterEvent
```

## Overview

Overview When you configure an audio unit as the destination for an AVMusicTrack that contains this event, you can schedule and automate parameter changes. When the track is playing as part of a sequence, the destination audio unit receives set-parameter messages whose values change smoothly along a linear ramp between each event’s beat location. If you add an event to an empty, non-automation track, the track becomes an automation track.

## Topics

### Creating a Parameter Event

- [init(parameterID:scope:element:value:)](avfaudio/avparameterevent/init(parameterid:scope:element:value:).md)

### Configuring a Parameter Event

- [parameterID](avfaudio/avparameterevent/parameterid.md)
- [scope](avfaudio/avparameterevent/scope.md)
- [element](avfaudio/avparameterevent/element.md)
- [value](avfaudio/avparameterevent/value.md)

## Relationships

### Inherits From

- [AVMusicEvent](avfaudio/avmusicevent.md)

### Conforms To

- [CVarArg](swift/cvararg.md)
- [CustomDebugStringConvertible](swift/customdebugstringconvertible.md)
- [CustomStringConvertible](swift/customstringconvertible.md)
- [Equatable](swift/equatable.md)
- [Hashable](swift/hashable.md)
- [NSObjectProtocol](objectivec/nsobjectprotocol.md)

## See Also

### Handling Music Events

- [AVMusicEvent](avfaudio/avmusicevent.md)
- [AVMusicUserEvent](avfaudio/avmusicuserevent.md)
- [AVAUPresetEvent](avfaudio/avaupresetevent.md)
- [AVExtendedTempoEvent](avfaudio/avextendedtempoevent.md)
- [AVExtendedNoteOnEvent](avfaudio/avextendednoteonevent.md)