Contents

setOutputPresentationTimeStamp(_:)

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

Declaration

func setOutputPresentationTimeStamp(_ pts: CMTime) throws

Parameters

  • pts:

    The output presentation timestamp.

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