---
title: overallDurationHint
framework: avfoundation
role: symbol
role_heading: Instance Property
path: avfoundation/avassetwriter/overalldurationhint
---

# overallDurationHint

A hint of the final duration of the output file.

## Declaration

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

## Discussion

Discussion The default value of invalid indicates that the asset writer doesn’t write an overall duration hint to the file. The asset writer ignores this value if it doesn’t write movie fragments. You can’t set this property after writing starts.

## See Also

### Configuring fragment output

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