---
title: CVFillExtendedPixelsCallBack
framework: corevideo
role: symbol
role_heading: Type Alias
path: corevideo/cvfillextendedpixelscallback
---

# CVFillExtendedPixelsCallBack

Defines a pointer to a custom extended pixel-fill function, which is called whenever the system needs to pad a buffer holding your custom pixel format.

## Declaration

```swift
typealias CVFillExtendedPixelsCallBack = (CVPixelBuffer, UnsafeMutableRawPointer?) -> DarwinBoolean
```

## Parameters

- `pixelBuffer`: The pixel buffer to be padded.
- `refCon`: A pointer to application-defined data. This is the same value you stored in the doc://com.apple.corevideo/documentation/CoreVideo/CVFillExtendedPixelsCallBackData structure.

## Return Value

Return Value If true, the padding was successful; otherwise, false.