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# CMIOExtensionStreamSource

A protocol for objects that act as stream sources.

```
protocol CMIOExtensionStreamSource : NSObjectProtocol
```

## Overview

Create a class that adopts this protocol to configure stream properties and manage the stream life cycle.

## Topics

### Accessing the Source Format

[`formats`](/documentation/CoreMediaIO/CMIOExtensionStreamSource/formats)

An array of formats that a stream supports.

[`CMIOExtensionStreamFormat`](/documentation/CoreMediaIO/CMIOExtensionStreamFormat)

An object that describes the format of a media stream.

### Managing Stream Properties

[`availableProperties`](/documentation/CoreMediaIO/CMIOExtensionStreamSource/availableProperties)

A set of properties available for the stream.

[`streamProperties(forProperties:)`](/documentation/CoreMediaIO/CMIOExtensionStreamSource/streamProperties(forProperties:))

Gets the states of specified properties.

[`setStreamProperties(_:)`](/documentation/CoreMediaIO/CMIOExtensionStreamSource/setStreamProperties(_:))

Sets the property state of a stream.

### Managing a Stream

[`authorizedToStartStream(for:)`](/documentation/CoreMediaIO/CMIOExtensionStreamSource/authorizedToStartStream(for:))

Determines whether to authorize an app to use this stream.

[`startStream()`](/documentation/CoreMediaIO/CMIOExtensionStreamSource/startStream())

Starts the stream of media data.

[`stopStream()`](/documentation/CoreMediaIO/CMIOExtensionStreamSource/stopStream())

Stops the stream of media data.


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