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# CVDisplayLinkGetNominalOutputVideoRefreshPeriod(_:)

Retrieves the nominal refresh period of a display link.

```
func CVDisplayLinkGetNominalOutputVideoRefreshPeriod(_ displayLink: CVDisplayLink) -> CVTime
```

## Parameters

`displayLink`

The display link whose refresh period you want to obtain.

## Return Value

A `CVTime` structure that holds the nominal refresh period. This value is indefinite if an invalid display link was specified.

## Discussion

This call allows one to retrieve the device’s ideal refresh period.   For example, an NTSC output device might report 1001/60000 to represent the exact NTSC vertical refresh rate.

---

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