---
title: kVTCompressionPropertyKey_PreserveAlphaChannel
framework: videotoolbox
role: symbol
role_heading: Global Variable
path: videotoolbox/kvtcompressionpropertykey_preservealphachannel
---

# kVTCompressionPropertyKey_PreserveAlphaChannel

A key that specifies whether to encode the alpha channel of input video frames.

## Declaration

```swift
let kVTCompressionPropertyKey_PreserveAlphaChannel: CFString
```

## Discussion

Discussion Set this property to false in cases where you’re not interested in preserving alpha, or if you know the alpha channel to be fully opaque. This property isn’t supported by all encoders.

## See Also

### Bitstream Configuration

- [kVTCompressionPropertyKey_Depth](videotoolbox/kvtcompressionpropertykey_depth.md)
- [kVTCompressionPropertyKey_H264EntropyMode](videotoolbox/kvtcompressionpropertykey_h264entropymode.md)
- [kVTCompressionPropertyKey_HDRMetadataInsertionMode](videotoolbox/kvtcompressionpropertykey_hdrmetadatainsertionmode.md)
- [kVTCompressionPropertyKey_OutputBitDepth](videotoolbox/kvtcompressionpropertykey_outputbitdepth.md)
- [kVTCompressionPropertyKey_PreserveDynamicHDRMetadata](videotoolbox/kvtcompressionpropertykey_preservedynamichdrmetadata.md)
- [kVTCompressionPropertyKey_ProfileLevel](videotoolbox/kvtcompressionpropertykey_profilelevel.md)