---
title: assemblyTrackID
framework: avfoundation
role: symbol
role_heading: Instance Property
path: avfoundation/avplannedsegmentwritingrequest/assemblytrackid
---

# assemblyTrackID

## Declaration

```swift
var assemblyTrackID: CMPersistentTrackID { get }
```

## Discussion

Discussion The trackID identifies which track should be written to this segment file. This is the same track ID in the AVAssetTrackPlan object. This is also the trackID the AVAssetWritingPlanner uses to build the assembled AVComposition before it calls the completion handler.

## See Also

### Inspecting the request

- [timeRange](avfoundation/avplannedsegmentwritingrequest/timerange.md)
- [segmentFileOutputURL](avfoundation/avplannedsegmentwritingrequest/segmentfileoutputurl.md)
- [progress](avfoundation/avplannedsegmentwritingrequest/progress.md)