---
title: "init(propertiesOf:)"
framework: avfoundation
role: symbol
role_heading: Initializer
path: "avfoundation/avmutablevideocomposition/init(propertiesof:)"
---

# init(propertiesOf:)

Creates a mutable video composition with the specified asset properties.

## Declaration

```swift
init(propertiesOf asset: AVAsset)
```

## Parameters

- `asset`: An instance of doc://com.apple.avfoundation/documentation/AVFoundation/AVAsset. Ensure that the duration and tracks properties of the asset are already loaded before invoking this method.

## Discussion

Discussion The returned AVMutableVideoComposition has instructions that respect the spatial properties and time ranges of the specified asset’s video tracks. It also has the following values for its properties: A value for frameDuration short enough to accommodate the greatest nominalFrameRate among the asset’s video tracks. If the nominalFrameRate of all of the asset’s video tracks is 0, a default frame rate of 30fps is used. If the specified asset is an instance of AVComposition, the renderSize is set to the naturalSize of the AVComposition; otherwise the renderSize will be set to a value that encompasses all of the asset’s video tracks. A renderScale of 1.0. The animationTool property set to nil.

## See Also

### Creating a video composition

- [videoComposition(withPropertiesOf:completionHandler:)](avfoundation/avmutablevideocomposition/videocomposition(withpropertiesof:completionhandler:).md)
- [videoComposition(withPropertiesOf:prototypeInstruction:completionHandler:)](avfoundation/avmutablevideocomposition/videocomposition(withpropertiesof:prototypeinstruction:completionhandler:).md)
- [videoComposition(with:applyingCIFiltersWithHandler:completionHandler:)](avfoundation/avmutablevideocomposition/videocomposition(with:applyingcifilterswithhandler:completionhandler:).md)
- [init(propertiesOf:prototypeInstruction:)](avfoundation/avmutablevideocomposition/init(propertiesof:prototypeinstruction:).md)
- [init(asset:applyingCIFiltersWithHandler:)](avfoundation/avmutablevideocomposition/init(asset:applyingcifilterswithhandler:).md)