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# add(_:)

Adds an output to the reader.

```
func add(_ output: AVAssetReaderOutput)
```

## Parameters

`output`

The asset reader output to add.

## Discussion

Add outputs to read from one or more tracks of an asset. You can only add outputs that retrieve media data from the asset that you associate with the asset reader.

You can’t add an output after you start reading.

---

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