---
title: "CVDisplayLinkGetActualOutputVideoRefreshPeriod(_:)"
framework: corevideo
role: symbol
role_heading: Function
path: "corevideo/cvdisplaylinkgetactualoutputvideorefreshperiod(_:)"
---

# CVDisplayLinkGetActualOutputVideoRefreshPeriod(_:)

Retrieves the actual output refresh period of a display as measured by the system time.

## Declaration

```swift
func CVDisplayLinkGetActualOutputVideoRefreshPeriod(_ displayLink: CVDisplayLink) -> Double
```

## Parameters

- `displayLink`: The display link to get the refresh period from.

## Return Value

Return Value A double-precision floating-point value representing the actual refresh period in seconds. This value may be zero if the device is not running or is otherwise unavailable.

## Discussion

Discussion This call returns the actual output refresh period computed relative to the system time (as measured using the CVGetCurrentHostTime() function).

## See Also

### Inspecting Display Links

- [CVDisplayLinkGetCurrentCGDisplay(_:)](corevideo/cvdisplaylinkgetcurrentcgdisplay(_:).md)
- [CVDisplayLinkGetCurrentTime(_:_:)](corevideo/cvdisplaylinkgetcurrenttime(_:_:).md)
- [CVDisplayLinkTranslateTime(_:_:_:)](corevideo/cvdisplaylinktranslatetime(_:_:_:).md)
- [CVDisplayLinkGetNominalOutputVideoRefreshPeriod(_:)](corevideo/cvdisplaylinkgetnominaloutputvideorefreshperiod(_:).md)
- [CVDisplayLinkGetOutputVideoLatency(_:)](corevideo/cvdisplaylinkgetoutputvideolatency(_:).md)
- [CVDisplayLinkIsRunning(_:)](corevideo/cvdisplaylinkisrunning(_:).md)
- [CVDisplayLinkGetTypeID()](corevideo/cvdisplaylinkgettypeid().md)