---
title: VTRAWProcessingParameterChangeHandler
framework: Video Toolbox
role: symbol
role_heading: Type Alias
platforms: [macOS 15.0+]
path: videotoolbox/vtrawprocessingparameterchangehandler
---

# VTRAWProcessingParameterChangeHandler

A function the system calls when processing parameters change.

## Declaration

```occ
typedef void (^)(const struct __CFArray *) VTRAWProcessingParameterChangeHandler;
```

## Parameters

- `newParameters`: An array containing the new parameter details. This follows the same form as the array returned from doc://com.apple.videotoolbox/documentation/VideoToolbox/VTRAWProcessingSessionCopyProcessingParameters.

## Discussion

Discussion The system invokes this callback when available parameters or parameter values change without an explicit call to VTRAWProcessingSessionSetProcessingParameters. This is intended to allow the client to update any UI driven by these parameters.

## See Also

### Data types

- [VTRAWProcessingSession](videotoolbox/vtrawprocessingsession.md)
- [VTRAWProcessingSessionSetParameterChangedHander](videotoolbox/vtrawprocessingsessionsetparameterchangedhander.md)
- [VTRAWProcessingOutputHandler](videotoolbox/vtrawprocessingoutputhandler.md)