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  "title" : "Image Buffer Clean Aperture Keys"
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# Image Buffer Clean Aperture Keys

Keys that describe the clean aperture of an image buffer.

## Discussion

Define these key-value pairs in a <doc://com.apple.documentation/documentation/CoreFoundation/CFDictionary> instance and use the [`kCVImageBufferCleanApertureKey`](/documentation/CoreVideo/kCVImageBufferCleanApertureKey) or [`kCVImageBufferPreferredCleanApertureKey`](/documentation/CoreVideo/kCVImageBufferPreferredCleanApertureKey) key to attach it to the image buffer. An image’s clean aperture is a region of video that’s free from transition artifacts caused by the encoding of the signal. This is the region of video to display.

## Topics

### Constants

[`let kCVImageBufferCleanApertureWidthKey: CFString`](/documentation/CoreVideo/kCVImageBufferCleanApertureWidthKey)

A key to the clean aperture width of the image buffer.

[`let kCVImageBufferCleanApertureHeightKey: CFString`](/documentation/CoreVideo/kCVImageBufferCleanApertureHeightKey)

A key to the clean aperture height of the image buffer.

[`let kCVImageBufferCleanApertureHorizontalOffsetKey: CFString`](/documentation/CoreVideo/kCVImageBufferCleanApertureHorizontalOffsetKey)

A key to the clean aperture horizontal offset value from the center of the image buffer.

[`let kCVImageBufferCleanApertureVerticalOffsetKey: CFString`](/documentation/CoreVideo/kCVImageBufferCleanApertureVerticalOffsetKey)

A key to the clean aperture vertical offset value from the center of the image buffer.


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