---
title: sourceTrackID
framework: avfoundation
role: symbol
role_heading: Instance Property
path: avfoundation/avcompositiontracksegment/sourcetrackid
---

# sourceTrackID

An identifier of a track in the container file whose media this track segment presents.

## Declaration

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

## See Also

### Accessing segment properties

- [sourceURL](avfoundation/avcompositiontracksegment/sourceurl.md)
- [isEmpty](avfoundation/avcompositiontracksegment/isempty.md)