---
title: AudioQueueTimelineRef
framework: audiotoolbox
role: symbol
role_heading: Type Alias
path: audiotoolbox/audioqueuetimelineref
---

# AudioQueueTimelineRef

Defines an opaque data type that represents an audio queue timeline object.

## Declaration

```swift
typealias AudioQueueTimelineRef = OpaquePointer
```

## Discussion

Discussion You can use a timeline object to observe time discontinuities in the audio hardware device associated with an audio queue. A discontinuity is, for example, a period of silence when sound was expected. Causes of discontinuities include changes in device state or data processing overloads. See Technical Q&A 1467, CoreAudio Overload Warnings. You query a timeline object by passing it as a parameter to the AudioQueueGetCurrentTime(_:_:_:_:) function.

## See Also

### Managing the Timeline

- [AudioQueueCreateTimeline(_:_:)](audiotoolbox/audioqueuecreatetimeline(_:_:).md)
- [AudioQueueDisposeTimeline(_:_:)](audiotoolbox/audioqueuedisposetimeline(_:_:).md)
- [AudioQueueDeviceGetCurrentTime(_:_:)](audiotoolbox/audioqueuedevicegetcurrenttime(_:_:).md)
- [AudioQueueDeviceGetNearestStartTime(_:_:_:)](audiotoolbox/audioqueuedevicegetneareststarttime(_:_:_:).md)
- [AudioQueueDeviceTranslateTime(_:_:_:)](audiotoolbox/audioqueuedevicetranslatetime(_:_:_:).md)
- [AudioQueueGetCurrentTime(_:_:_:_:)](audiotoolbox/audioqueuegetcurrenttime(_:_:_:_:).md)