---
title: kVTCompressionPropertyKey_TargetQualityForAlpha
framework: videotoolbox
role: symbol
role_heading: Global Variable
path: videotoolbox/kvtcompressionpropertykey_targetqualityforalpha
---

# kVTCompressionPropertyKey_TargetQualityForAlpha

The target quality to use for encoding the alpha channel.

## Declaration

```swift
let kVTCompressionPropertyKey_TargetQualityForAlpha: CFString
```

## Discussion

Discussion Specify this value as a number in the range of 0.0 for the lowest quality to 1.0 for nearly lossless quality. Alpha plane bit rates tend to increase with increasing values. When encoding the alpha channel, the system gives priority to quality over bitrate. important: Only HEVC with Alpha encoders support this parameter.

## See Also

### Rate Control

- [kVTCompressionPropertyKey_AverageBitRate](videotoolbox/kvtcompressionpropertykey_averagebitrate.md)
- [kVTCompressionPropertyKey_ConstantBitRate](videotoolbox/kvtcompressionpropertykey_constantbitrate.md)
- [kVTCompressionPropertyKey_DataRateLimits](videotoolbox/kvtcompressionpropertykey_dataratelimits.md)
- [kVTCompressionPropertyKey_EstimatedAverageBytesPerFrame](videotoolbox/kvtcompressionpropertykey_estimatedaveragebytesperframe.md)
- [kVTCompressionPropertyKey_MoreFramesAfterEnd](videotoolbox/kvtcompressionpropertykey_moreframesafterend.md)
- [kVTCompressionPropertyKey_MoreFramesBeforeStart](videotoolbox/kvtcompressionpropertykey_moreframesbeforestart.md)
- [kVTCompressionPropertyKey_Quality](videotoolbox/kvtcompressionpropertykey_quality.md)
- [kVTCompressionPropertyKey_VariableBitRate](videotoolbox/kvtcompressionpropertykey_variablebitrate.md)
- [kVTCompressionPropertyKey_VBVBufferDuration](videotoolbox/kvtcompressionpropertykey_vbvbufferduration.md)
- [kVTCompressionPropertyKey_VBVInitialDelayPercentage](videotoolbox/kvtcompressionpropertykey_vbvinitialdelaypercentage.md)
- [kVTCompressionPropertyKey_VBVMaxBitRate](videotoolbox/kvtcompressionpropertykey_vbvmaxbitrate.md)