---
title: CMBufferGetTimeCallback
framework: coremedia
role: symbol
role_heading: Type Alias
path: coremedia/cmbuffergettimecallback
---

# CMBufferGetTimeCallback

Callback that returns a CMTime from a CMBuffer.

## Declaration

```swift
typealias CMBufferGetTimeCallback = (CMBuffer, UnsafeMutableRawPointer?) -> CMTime
```

## Discussion

Discussion There are three callbacks of this type that can be provided to Creating Buffer Queues: getDuration (required), getDecodeTimeStamp (optional), and getPresentationTimeStamp (optional). Callback Parameters

## See Also

### Properties

- [compare](coremedia/cmbuffercallbacks/compare.md)
- [CMBufferCompareCallback](coremedia/cmbuffercomparecallback.md)
- [CMBufferGetBooleanCallback](coremedia/cmbuffergetbooleancallback.md)
- [dataBecameReadyNotification](coremedia/cmbuffercallbacks/databecamereadynotification.md)
- [getDecodeTimeStamp](coremedia/cmbuffercallbacks/getdecodetimestamp.md)
- [getDuration](coremedia/cmbuffercallbacks/getduration.md)
- [getPresentationTimeStamp](coremedia/cmbuffercallbacks/getpresentationtimestamp.md)
- [getSize](coremedia/cmbuffercallbacks/getsize.md)
- [isDataReady](coremedia/cmbuffercallbacks/isdataready.md)
- [refcon](coremedia/cmbuffercallbacks/refcon.md)
- [version](coremedia/cmbuffercallbacks/version.md)