---
title: "vImageBuffer_InitForCopyToCVPixelBuffer(_:_:_:_:)"
framework: accelerate
role: symbol
role_heading: Function
path: "accelerate/vimagebuffer_initforcopytocvpixelbuffer(_:_:_:_:)"
---

# vImageBuffer_InitForCopyToCVPixelBuffer(_:_:_:_:)

Initializes an array of vImage buffers in the order necessary to copy to a Core Video pixel buffer.

## Declaration

```swift
func vImageBuffer_InitForCopyToCVPixelBuffer(_ buffers: UnsafeMutablePointer<vImage_Buffer>, _ converter: vImageConverter, _ pixelBuffer: CVPixelBuffer, _ flags: vImage_Flags) -> vImage_Error
```

## Parameters

- `buffers`: An array of doc://com.apple.accelerate/documentation/Accelerate/vImage_Buffer structures. The number of destination buffers is the return value of doc://com.apple.accelerate/documentation/Accelerate/vImageConverter_GetNumberOfDestinationBuffers(_:).
- `converter`: A Core-Graphics-to-Core-Video doc://com.apple.accelerate/documentation/Accelerate/vImageConverter instance.
- `pixelBuffer`: A locked doc://com.apple.documentation/documentation/CoreVideo/CVPixelBuffer instance.
- `flags`: The options to use when performing this operation. important: Always pass the doc://com.apple.accelerate/documentation/Accelerate/kvImageNoAllocate flag to this function. The doc://com.apple.accelerate/documentation/Accelerate/kvImageNoAllocate flag instructs the function to initialize the buffers to read directly from a locked doc://com.apple.documentation/documentation/CoreVideo/CVPixelBuffer instance. All operations that use the buffers must be between calls to the doc://com.apple.documentation/documentation/CoreVideo/CVPixelBufferLockBaseAddress(_:_:) and doc://com.apple.documentation/documentation/CoreVideo/CVPixelBufferUnlockBaseAddress(_:_:) functions.

## Return Value

Return Value kvImageNoError; otherwise, one of the error codes in Data Types and Constants.

## Discussion

Discussion The vImage library represents multiple plane Core Video pixel buffers as individual vImage buffers. Call vImageConverter_GetNumberOfDestinationBuffers(_:) to instantiate the correct number of destination buffers. Use this function to initialize the vImage buffers that you pass as the destinations to a Core-Video-to-Core-Graphics vImageConverter instance. The following shows the code for creating the three destination buffers required to represent a kCVPixelFormatType_420YpCbCr8Planar pixel buffer. On return of vImageConvert_AnyToAny(_:_:_:_:_:), the three vImage buffers contain the luminance, Cb, and Cr image data. let colorSpace = CGColorSpaceCreateDeviceRGB()

guard     let cgImageFormat = vImage_CGImageFormat(         bitsPerComponent: 8,         bitsPerPixel: 32,         colorSpace: colorSpace,         bitmapInfo: CGBitmapInfo(rawValue: CGImageAlphaInfo.noneSkipFirst.rawValue),         renderingIntent: .defaultIntent),          let cvImageFormat = vImageCVImageFormat.make(         format: .format420YpCbCr8Planar,         matrix: kvImage_ARGBToYpCbCrMatrix_ITU_R_709_2.pointee,         chromaSiting: .center,         colorSpace: colorSpace,         alphaIsOpaqueHint: false),          let converterCGtoCV = try? vImageConverter.make(         sourceFormat: cgImageFormat,         destinationFormat: cvImageFormat) else {     return }

let destinationBufferCount = vImageConverter_GetNumberOfDestinationBuffers(converterCGtoCV) var destinationBuffers = (0 ..< destinationBufferCount).map { _ in     return vImage_Buffer() }

// `cvPixelBuffer` is the destination Core Video pixel buffer. CVPixelBufferLockBaseAddress(cvPixelBuffer,                              CVPixelBufferLockFlags(rawValue: 0))

// Initialize the destination buffers. vImageBuffer_InitForCopyToCVPixelBuffer(     &destinationBuffers,     converterCGtoCV,     cvPixelBuffer,     vImage_Flags(kvImageNoAllocate))

// The source has an interleaved format with one or more channels, and  // is encodable with a `vImage_CGImageFormat`. assert(vImageConverter_GetNumberOfSourceBuffers(converterCGtoCV) == 1)

// On return, `destinationBuffers` contains the YpCbCr conversion of the RGB // image data in the vImage source buffer. // `sourceBuffer` is the source vImage buffer. vImageConvert_AnyToAny(converterCGtoCV,                        &sourceBuffer,                        &destinationBuffers,                        nil,                        vImage_Flags(kvImageNoFlags))

CVPixelBufferUnlockBaseAddress(cvPixelBuffer,                                CVPixelBufferLockFlags(rawValue: 0))

## See Also

### Initializing vImage buffers that reference Core Video pixel buffer data

- [vImageBuffer_InitForCopyFromCVPixelBuffer(_:_:_:_:)](accelerate/vimagebuffer_initforcopyfromcvpixelbuffer(_:_:_:_:).md)