---
title: kVTCompressionPropertyKey_CleanAperture
framework: videotoolbox
role: symbol
role_heading: Global Variable
path: videotoolbox/kvtcompressionpropertykey_cleanaperture
---

# kVTCompressionPropertyKey_CleanAperture

The clean aperture for encoded frames.

## Declaration

```swift
let kVTCompressionPropertyKey_CleanAperture: CFString
```

## Discussion

Discussion If a video encoder enforces specific clean apertures, this property is read-only (VTSessionSetProperty(_:key:value:) will return kVTPropertyReadOnlyErr). The clean aperture will be set on the format description for output samples, and may affect source frame scaling. NULL is a valid value for this property, meaning that the clean aperture is the full width and height.

## See Also

### Clean Aperture and Pixel Aspect Ratio

- [kVTCompressionPropertyKey_AspectRatio16x9](videotoolbox/kvtcompressionpropertykey_aspectratio16x9.md)
- [kVTCompressionPropertyKey_FieldCount](videotoolbox/kvtcompressionpropertykey_fieldcount.md)
- [kVTCompressionPropertyKey_FieldDetail](videotoolbox/kvtcompressionpropertykey_fielddetail.md)
- [kVTCompressionPropertyKey_PixelAspectRatio](videotoolbox/kvtcompressionpropertykey_pixelaspectratio.md)
- [kVTCompressionPropertyKey_ProgressiveScan](videotoolbox/kvtcompressionpropertykey_progressivescan.md)