---
title: "setOutputPresentationTimeStamp(_:)"
framework: coremedia
role: symbol
role_heading: Instance Method
path: "coremedia/cmsamplebuffer/setoutputpresentationtimestamp(_:)"
---

# setOutputPresentationTimeStamp(_:)

Sets an output presentation timestamp to use in place of a calculated value.

## Declaration

```swift
func setOutputPresentationTimeStamp(_ pts: CMTime) throws
```

## Parameters

- `pts`: The output presentation timestamp.

## Discussion

Discussion This value is the time at which the system should present the decoded, trimmed, stretched and possibly reversed samples. By default, retrieving the value of the outputPresentationTimeStamp property calculates the time dynamically. You can use this method to set a specific value for outputPresentationTimeStamp. For general forward playback in a scaled edit, calculate the timestamp as follows: ((PresentationTimeStamp + TrimDurationAtStart - EditStartMediaTime) / EditSpeedMultiplier) + EditStartTrackTime For general reversed playback, calculate the timestamp as shown below: ((PresentationTimeStamp + Duration - TrimDurationAtEnd - EditStartMediaTime) / EditSpeedMultiplier) + EditStartTrackTime

## See Also

### Inspecting Duration and Timing

- [duration](coremedia/cmsamplebuffer/duration.md)
- [decodeTimeStamp](coremedia/cmsamplebuffer/decodetimestamp.md)
- [presentationTimeStamp](coremedia/cmsamplebuffer/presentationtimestamp.md)
- [outputDuration](coremedia/cmsamplebuffer/outputduration.md)
- [outputDecodeTimeStamp](coremedia/cmsamplebuffer/outputdecodetimestamp.md)
- [outputPresentationTimeStamp](coremedia/cmsamplebuffer/outputpresentationtimestamp.md)
- [sampleTimingInfos()](coremedia/cmsamplebuffer/sampletiminginfos().md)
- [sampleTimingInfo(at:)](coremedia/cmsamplebuffer/sampletiminginfo(at:).md)
- [outputSampleTimingInfos()](coremedia/cmsamplebuffer/outputsampletiminginfos().md)