---
title: movieFragmentInterval
framework: avfoundation
role: symbol
role_heading: Instance Property
path: avfoundation/avassetwriter/moviefragmentinterval
---

# movieFragmentInterval

The interval at which to write movie fragments.

## Declaration

```swift
var movieFragmentInterval: CMTime { get set }
```

## Discussion

Discussion Some container formats, such as QuickTime movies, support writing movies in fragments. Using this feature enables you to open and play a partially written movie in the event that an unexpected error or interruption occurs. An asset writer disables this feature by default and sets this value to invalid. To enable fragment writing, set a valid CMTime value. For best performance when writing to external storage devices, set the movie fragment interval to 10 seconds or greater. You can’t set this value after writing starts.

## See Also

### Configuring fragment output

- [initialMovieFragmentInterval](avfoundation/avassetwriter/initialmoviefragmentinterval.md)
- [initialMovieFragmentSequenceNumber](avfoundation/avassetwriter/initialmoviefragmentsequencenumber.md)
- [producesCombinableFragments](avfoundation/avassetwriter/producescombinablefragments.md)
- [overallDurationHint](avfoundation/avassetwriter/overalldurationhint.md)
- [movieTimeScale](avfoundation/avassetwriter/movietimescale.md)