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# canPerformMultiplePassesOverSourceMediaData

A Boolean value that indicates whether the export session can perform multiple passes over the source media to achieve better results.

```
var canPerformMultiplePassesOverSourceMediaData: Bool { get set }
```

## Discussion

When the value for this property is <doc://com.apple.documentation/documentation/Swift/true>, the export session can produce higher quality results at the expense of longer export times. Setting this property to <doc://com.apple.documentation/documentation/Swift/true> may also require the export session to write temporary data to disk during the export. To control the location of temporary data, use the property [`directoryForTemporaryFiles`](/documentation/AVFoundation/AVAssetExportSession/directoryForTemporaryFiles).

The default value is <doc://com.apple.documentation/documentation/Swift/false>. Not all export session configurations can benefit from performing multiple passes over the source media. In these cases, setting this property to <doc://com.apple.documentation/documentation/Swift/true> has no effect.

You can’t set this property after the export starts.

---

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