---
title: kVTCompressionPropertyKey_AverageBitRate
framework: videotoolbox
role: symbol
role_heading: Global Variable
path: videotoolbox/kvtcompressionpropertykey_averagebitrate
---

# kVTCompressionPropertyKey_AverageBitRate

The long-term desired average bit rate in bits per second.

## Declaration

```swift
let kVTCompressionPropertyKey_AverageBitRate: CFString
```

## Discussion

Discussion This value is not a hard limit; the bit rate may peak above this. The default bit rate is zero, which indicates that the video encoder should determine the size of compressed data. Note that bit rate settings only have an effect when timing information is provided for source frames, and that some codecs do not support limiting to specified bit rates.

## See Also

### Rate Control

- [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_TargetQualityForAlpha](videotoolbox/kvtcompressionpropertykey_targetqualityforalpha.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)