<!--
{
  "availability" : [
    "iOS: -",
    "iPadOS: -",
    "macCatalyst: -",
    "macOS: -",
    "tvOS: -",
    "visionOS: -"
  ],
  "documentType" : "symbol",
  "framework" : "AudioToolbox",
  "identifier" : "/documentation/AudioToolbox/MusicEventType",
  "metadataVersion" : "0.1.0",
  "role" : "Type Alias",
  "symbol" : {
    "kind" : "Type Alias",
    "modules" : [
      "Audio Toolbox"
    ],
    "preciseIdentifier" : "c:@T@MusicEventType"
  },
  "title" : "MusicEventType"
}
-->

# MusicEventType

MIDI and other music event types, used by music event iterator functions.

```
typealias MusicEventType = UInt32
```

## Topics

### Constants

[`kMusicEventType_NULL`](/documentation/AudioToolbox/kMusicEventType_NULL)

A null music event.

[`kMusicEventType_ExtendedNote`](/documentation/AudioToolbox/kMusicEventType_ExtendedNote)

A non-MIDI music event with variable number of parameters.

[`kMusicEventType_ExtendedTempo`](/documentation/AudioToolbox/kMusicEventType_ExtendedTempo)

An event that signals a change in tempo, in beats-per-minute.

[`kMusicEventType_User`](/documentation/AudioToolbox/kMusicEventType_User)

User-defined data.

[`kMusicEventType_Meta`](/documentation/AudioToolbox/kMusicEventType_Meta)

A standard MIDI file metaevent.

[`kMusicEventType_MIDINoteMessage`](/documentation/AudioToolbox/kMusicEventType_MIDINoteMessage)

A MIDI note-on message, including duration.

[`kMusicEventType_MIDIChannelMessage`](/documentation/AudioToolbox/kMusicEventType_MIDIChannelMessage)

A MIDI channel message, other than note control.

[`kMusicEventType_MIDIRawData`](/documentation/AudioToolbox/kMusicEventType_MIDIRawData)

MIDI system-exclusive data.

[`kMusicEventType_Parameter`](/documentation/AudioToolbox/kMusicEventType_Parameter)

An audio unit parameter event.

[`kMusicEventType_AUPreset`](/documentation/AudioToolbox/kMusicEventType_AUPreset)

An event containing an audio unit user preset dictionary.


---

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)