---
title: "CMSampleBufferTrackDataReadiness(_:sampleBufferToTrack:)"
framework: coremedia
role: symbol
role_heading: Function
path: "coremedia/cmsamplebuffertrackdatareadiness(_:samplebuffertotrack:)"
---

# CMSampleBufferTrackDataReadiness(_:sampleBufferToTrack:)

Associates a sample buffer’s data readiness with that of another sample buffer.

## Declaration

```swift
func CMSampleBufferTrackDataReadiness(_ sbuf: CMSampleBuffer, sampleBufferToTrack: CMSampleBuffer) -> OSStatus
```

## Parameters

- `sbuf`: The sample buffer being modified.
- `sampleBufferToTrack`: The sample buffer being tracked.

## Return Value

Return Value A result code. See Sample Buffer Error Codes.

## Discussion

Discussion After calling this API, if CMSampleBufferDataIsReady is called, it will return sampleBufferToTrack’s data readiness. If CMSampleBufferMakeDataReady is called, it will make sampleBufferToTrack data ready. Example of use: This allows bursting a multi-sample CMSampleBuffer into single-sample CMSampleBuffers before the data is ready. The single-sample CMSampleBuffers will all track the multi-sample CMSampleBuffer’s data readiness.

## See Also

### Determining Readiness

- [CMSampleBufferDataIsReady(_:)](coremedia/cmsamplebufferdataisready(_:).md)
- [CMSampleBufferSetDataReady(_:)](coremedia/cmsamplebuffersetdataready(_:).md)
- [CMSampleBufferSetDataFailed(_:status:)](coremedia/cmsamplebuffersetdatafailed(_:status:).md)
- [CMSampleBufferHasDataFailed(_:statusOut:)](coremedia/cmsamplebufferhasdatafailed(_:statusout:).md)
- [CMSampleBufferMakeDataReady(_:)](coremedia/cmsamplebuffermakedataready(_:).md)