# vImageBuffer_InitWithCVPixelBuffer(_:_:_:_:_:_:) Initializes a vImage buffer with a copy of the contents of a Core Video pixel buffer. ``` func vImageBuffer_InitWithCVPixelBuffer(_ buffer: UnsafeMutablePointer, _ desiredFormat: UnsafeMutablePointer, _ cvPixelBuffer: CVPixelBuffer, _ cvImageFormat: vImageCVImageFormat!, _ backgroundColor: UnsafePointer!, _ flags: vImage_Flags) -> vImage_Error ``` ## Parameters `buffer` The destination empty [`vImage_Buffer`](/documentation/Accelerate/vImage_Buffer) structure. On return, the function allocates new memory to the buffer and sets the buffer’s size to match the instance’s dimensions. `desiredFormat` A [`vImage_CGImageFormat`](/documentation/Accelerate/vImage_CGImageFormat) structure that specifies the image format of the [`vImage_Buffer`](/documentation/Accelerate/vImage_Buffer) structure. If [`colorSpace`](/documentation/Accelerate/vImage_CGImageFormat/colorSpace) is `nil`, the function uses . `cvPixelBuffer` The source instance. It’s not necessary to lock the pixel buffer before calling this function. `cvImageFormat` An optional [`vImageCVImageFormat`](/documentation/Accelerate/vImageCVImageFormat) instance that specifies the pixel format of the source pixel buffer. If this parameter is `nil`, the function attempts to derive this information from the Core Video pixel buffer. `backgroundColor` If the source image contains alpha information and the destination format doesn’t contain alpha information, this function flattens the source image against this parameter. `flags` The options to use when performing the operation. If your code implements its own tiling or its own multithreading, pass [`kvImageDoNotTile`](/documentation/Accelerate/kvImageDoNotTile); otherwise, pass [`kvImageNoFlags`](/documentation/Accelerate/kvImageNoFlags). Pass [`kvImageNoAllocate`](/documentation/Accelerate/kvImageNoAllocate) if the destination buffer references existing data. If the pixel buffer uses chrominance subsampling and you want vImage to use a higher quality, but a slower, resampling filter, set the [`kvImageHighQualityResampling`](/documentation/Accelerate/kvImageHighQualityResampling) flag. ## Return Value [`kvImageNoError`](/documentation/Accelerate/kvImageNoError); otherwise, one of the error codes in . ## Discussion Some Core Video pixel buffers and image formats have incompletely specified color information that prevents [`vImageBuffer_InitWithCVPixelBuffer(_:_:_:_:_:_:)`](/documentation/Accelerate/vImageBuffer_InitWithCVPixelBuffer(_:_:_:_:_:_:)) from performing the conversion. In this situation, the function returns one of the format errors below. To proceed, create a [`vImageCVImageFormat`](/documentation/Accelerate/vImageCVImageFormat) instance, add the missing information, and pass the image format instance as the `cvImageFormat` parameter to this function. It’s possible that more than one piece of information is missing. - [`kvImageCVImageFormat_ConversionMatrix`](/documentation/Accelerate/kvImageCVImageFormat_ConversionMatrix): The conversion matrix is missing from the `cvPixelBuffer` or the `vImageCVImageFormat`. Use the [`vImageCVImageFormat_CopyConversionMatrix(_:_:_:)`](/documentation/Accelerate/vImageCVImageFormat_CopyConversionMatrix(_:_:_:)) function to copy a conversion matrix to an image format. - [`kvImageCVImageFormat_ChromaSiting`](/documentation/Accelerate/kvImageCVImageFormat_ChromaSiting): The chrominance siting information is missing from the `cvPixelBuffer` or the `vImageCVImageFormat`. Use [`vImageCVImageFormat_SetChromaSiting(_:_:)`](/documentation/Accelerate/vImageCVImageFormat_SetChromaSiting(_:_:)) to set the chrominance siting on an image format. - [`kvImageCVImageFormat_ColorSpace`](/documentation/Accelerate/kvImageCVImageFormat_ColorSpace): The color space that contains primaries and transfer function is missing from the `cvPixelBuffer` or the `vImageCVImageFormat`. Use [`vImageCVImageFormat_SetColorSpace(_:_:)`](/documentation/Accelerate/vImageCVImageFormat_SetColorSpace(_:_:)) to set the color space on an image format. ## Discussion For compatibility with Core Video, vImage substitutes gamma `1/1.961` for and substitutes the ITU-R BT.709-5 transfer function for . You can manually set the transfer function using [`vImageCreateRGBColorSpaceWithPrimariesAndTransferFunction(_:_:_:_:_:)`](/documentation/Accelerate/vImageCreateRGBColorSpaceWithPrimariesAndTransferFunction(_:_:_:_:_:)) and [`vImageCVImageFormat_SetColorSpace(_:_:)`](/documentation/Accelerate/vImageCVImageFormat_SetColorSpace(_:_:)) to avoid this substitution. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)