---
title: beginConfiguration()
framework: avfoundation
role: symbol
role_heading: Instance Method
path: avfoundation/avcapturesession/beginconfiguration()
---

# beginConfiguration()

Marks the beginning of changes to a running capture session’s configuration to perform in a single atomic update.

## Declaration

```swift
func beginConfiguration()
```

## Mentioned in

Setting up a capture session

## Discussion

Discussion Call this method and commitConfiguration() to batch multiple configuration operations on a running session into an atomic update. After you call this method, you can add or remove outputs, alter the sessionPreset, or configure individual capture input or output properties. The session configuration doesn’t change until you invoke commitConfiguration(), at which the system updates all settings. You can nest beginConfiguration() and commitConfiguration() pairs, and the system applies the changes when you call the outermost commit.

## See Also

### Configuring a session

- [commitConfiguration()](avfoundation/avcapturesession/commitconfiguration().md)