---
title: "CMTimebaseCopySource(_:)"
framework: coremedia
role: symbol
role_heading: Function
path: "coremedia/cmtimebasecopysource(_:)"
---

# CMTimebaseCopySource(_:)

Returns the immediate source — either a clock or timebase — of a timebase.

## Declaration

```swift
func CMTimebaseCopySource(_ timebase: CMTimebase) -> CMClockOrTimebase
```

## See Also

### Copying Timebases

- [CMTimebaseCopySourceClock(_:)](coremedia/cmtimebasecopysourceclock(_:).md)
- [CMTimebaseCopySourceTimebase(_:)](coremedia/cmtimebasecopysourcetimebase(_:).md)
- [CMTimebaseCopyUltimateSourceClock(_:)](coremedia/cmtimebasecopyultimatesourceclock(_:).md)