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  "title" : "Image Buffer Attachment Keys"
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# Image Buffer Attachment Keys

Keys that describe the attachment types associated with image buffers.

## Discussion

An image buffer associates its attachment keys in a <doc://com.apple.documentation/documentation/CoreFoundation/CFDictionary> instance. To read and write these image buffer attachments, use the [`CVBufferCopyAttachment(_:_:_:)`](/documentation/CoreVideo/CVBufferCopyAttachment(_:_:_:)) and [`CVBufferSetAttachment(_:_:_:_:)`](/documentation/CoreVideo/CVBufferSetAttachment(_:_:_:_:)) functions or other [`CVBuffer`](/documentation/CoreVideo/CVBuffer) functions. See the [CVBuffer](/documentation/CoreVideo/cvbuffer-nfm) topic group for additional information.

## Topics

### Constants

[`kCVImageBufferCGColorSpaceKey`](/documentation/CoreVideo/kCVImageBufferCGColorSpaceKey)

A key to the color space of the image buffer.

[`kCVImageBufferCleanApertureKey`](/documentation/CoreVideo/kCVImageBufferCleanApertureKey)

A key to the dictionary describing the clean aperture for the image buffer.

[`kCVImageBufferPreferredCleanApertureKey`](/documentation/CoreVideo/kCVImageBufferPreferredCleanApertureKey)

A key to the dictionary describing the preferred clean aperture for the image buffer.

[`kCVImageBufferFieldCountKey`](/documentation/CoreVideo/kCVImageBufferFieldCountKey)

A key to the field count for the image buffer.

[`kCVImageBufferFieldDetailKey`](/documentation/CoreVideo/kCVImageBufferFieldDetailKey)

A key to the field detail for an image buffer that indicates the order of interlaced video data in the image buffer.

[`kCVImageBufferPixelAspectRatioKey`](/documentation/CoreVideo/kCVImageBufferPixelAspectRatioKey)

A key to the dictionary describing the pixel aspect ratio for the image buffer.

[`kCVImageBufferDisplayDimensionsKey`](/documentation/CoreVideo/kCVImageBufferDisplayDimensionsKey)

A key to the dictionary describing the display dimensions for the image buffer.

[`kCVImageBufferGammaLevelKey`](/documentation/CoreVideo/kCVImageBufferGammaLevelKey)

A key to the gamma level for the image buffer.

[`kCVImageBufferICCProfileKey`](/documentation/CoreVideo/kCVImageBufferICCProfileKey)

A key to the ICC color profile for the image buffer.

[`kCVImageBufferYCbCrMatrixKey`](/documentation/CoreVideo/kCVImageBufferYCbCrMatrixKey)

A key to the YCbCr to RGB color conversion matrix for the image buffer.

[`kCVImageBufferColorPrimariesKey`](/documentation/CoreVideo/kCVImageBufferColorPrimariesKey)

A key to the color primaries gamut for the image buffer.

[`kCVImageBufferTransferFunctionKey`](/documentation/CoreVideo/kCVImageBufferTransferFunctionKey)

A key to the transfer function for the image buffer.

[`kCVImageBufferChromaLocationTopFieldKey`](/documentation/CoreVideo/kCVImageBufferChromaLocationTopFieldKey)

A key to the location of chroma top field information in the image buffer.

[`kCVImageBufferChromaLocationBottomFieldKey`](/documentation/CoreVideo/kCVImageBufferChromaLocationBottomFieldKey)

A key to the location of chroma bottom field information in the image buffer.

[`kCVImageBufferChromaSubsamplingKey`](/documentation/CoreVideo/kCVImageBufferChromaSubsamplingKey)

A key to the original format of subsampled data in the image buffer.

[`kCVImageBufferAlphaChannelIsOpaque`](/documentation/CoreVideo/kCVImageBufferAlphaChannelIsOpaque)

A key to indicate whether the alpha channel is fully opaque.

[`kCVImageBufferContentLightLevelInfoKey`](/documentation/CoreVideo/kCVImageBufferContentLightLevelInfoKey)

A key to the content light level information.

[`kCVImageBufferMasteringDisplayColorVolumeKey`](/documentation/CoreVideo/kCVImageBufferMasteringDisplayColorVolumeKey)

A key to the mastering display color volume.

[`kCVImageBufferPostDecodeProcessingFrameMetadataKey`](/documentation/CoreVideo/kCVImageBufferPostDecodeProcessingFrameMetadataKey)

[`kCVImageBufferPostDecodeProcessingSequenceMetadataKey`](/documentation/CoreVideo/kCVImageBufferPostDecodeProcessingSequenceMetadataKey)

[`kCVImageBufferSceneIlluminationKey`](/documentation/CoreVideo/kCVImageBufferSceneIlluminationKey)

[`kCVImageBufferHorizontalDisparityAdjustmentKey`](/documentation/CoreVideo/kCVImageBufferHorizontalDisparityAdjustmentKey)


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