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# Pixel Aspect Ratio Extension Constants

Constants that identify pixel aspect ratio extensions.

## Topics

### Constants

[`let kCMFormatDescriptionKey_PixelAspectRatioHorizontalSpacing: CFString`](/documentation/CoreMedia/kCMFormatDescriptionKey_PixelAspectRatioHorizontalSpacing-swift.var)

A key that identifies the horizontal spacing of the pixel aspect ratio.

[`let kCMFormatDescriptionKey_PixelAspectRatioVerticalSpacing: CFString`](/documentation/CoreMedia/kCMFormatDescriptionKey_PixelAspectRatioVerticalSpacing-swift.var)

A key that identifies the vertical spacing of the pixel aspect ratio.


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