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# featureExtractionTimeWindowSize

A time duration, in seconds, that determines how much audio data the feature-extraction session reads each
time it samples an audio file.

```
var featureExtractionTimeWindowSize: TimeInterval { get set }
```

## Discussion

The time-window size defaults to `0.975` seconds and must be in the range `[0.5, 15.0]`.

Feature-extraction sessions that use
[`MLSoundClassifier.ModelParameters.FeatureExtractorType.vggish(revision:)`](/documentation/CreateML/MLSoundClassifier/ModelParameters-swift.struct/FeatureExtractorType/vggish(revision:))
ignore this value and always use a time-window size of `0.975` seconds.

---

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