---
title: "CMTimebaseSetRateAndAnchorTime(_:rate:anchorTime:immediateSourceTime:)"
framework: coremedia
role: symbol
role_heading: Function
path: "coremedia/cmtimebasesetrateandanchortime(_:rate:anchortime:immediatesourcetime:)"
---

# CMTimebaseSetRateAndAnchorTime(_:rate:anchorTime:immediateSourceTime:)

Sets the time of a timebase at a particular host time, and changes the rate at exactly that time.

## Declaration

```swift
func CMTimebaseSetRateAndAnchorTime(_ timebase: CMTimebase, rate: Float64, anchorTime timebaseTime: CMTime, immediateSourceTime: CMTime) -> OSStatus
```

## Discussion

Discussion The system interpolates CMTimebaseGetTime’s results from the anchor time as though the timebase has been running at the requested rate since that time. CMTimebaseSetRate(timebase, rate) is approximately equivalent to calling CMTimebaseSetRateAndAnchorTime(timebase, rate, CMTimebaseGetTime(timebase), CMSyncGetTime(CMTimebaseGetMaster(timebase))), except that CMTimebaseSetRate doesn’t generate a TimeJumped notification.

## See Also

### Getting and Setting the Time Rate

- [CMTimebaseGetRate(_:)](coremedia/cmtimebasegetrate(_:).md)
- [CMTimebaseGetEffectiveRate(_:)](coremedia/cmtimebasegeteffectiverate(_:).md)
- [CMTimebaseSetRate(_:rate:)](coremedia/cmtimebasesetrate(_:rate:).md)