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# trackDataReadiness(_:)

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

```
func trackDataReadiness(_ sampleBufferToTrack: CMSampleBuffer) throws
```

## Parameters

`sampleBufferToTrack`

The sample buffer for which to track readiness.

## Discussion

After calling this method, retrieving the value of the [`dataReadiness`](/documentation/CoreMedia/CMSampleBuffer/dataReadiness-swift.property) property retrieves the value from the tracked sample buffer. Likewise, calling the [`makeDataReady()`](/documentation/CoreMedia/CMSampleBuffer/makeDataReady()) method calls the tracked sample buffers method.

Use this method to convert a multi-sample buffer into single-sample buffer before the data is ready. The single-sample buffer tracks the data readiness of the multi-sample buffers.

---

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