---
title: isVideoFrameDurationLocked
framework: avfoundation
role: symbol
role_heading: Instance Property
path: avfoundation/avcapturedevice/isvideoframedurationlocked
---

# isVideoFrameDurationLocked

Whether the device’s video frame rate (expressed as a duration) is currently locked.

## Declaration

```swift
var isVideoFrameDurationLocked: Bool { get }
```

## Discussion

Discussion Returns true when an AVCaptureDeviceInput associated with the device has its activeLockedVideoFrameDuration property set to something other than kCMTimeInvalid. See activeLockedVideoFrameDuration for more information on video frame duration locking.

## See Also

### Synchronizing with external devices

- [isFollowingExternalSyncDevice](avfoundation/avcapturedevice/isfollowingexternalsyncdevice.md)
- [minSupportedExternalSyncFrameDuration](avfoundation/avcapturedevice/minsupportedexternalsyncframeduration.md)
- [minSupportedLockedVideoFrameDuration](avfoundation/avcapturedevice/minsupportedlockedvideoframeduration.md)