---
title: kVTCompressionPropertyKey_ExpectedDuration
framework: videotoolbox
role: symbol
role_heading: Global Variable
path: videotoolbox/kvtcompressionpropertykey_expectedduration
---

# kVTCompressionPropertyKey_ExpectedDuration

The expected total duration of the compression session, if known.

## Declaration

```swift
let kVTCompressionPropertyKey_ExpectedDuration: CFString
```

## Discussion

Discussion By default, this value is 0, indicating the duration is unknown.

## See Also

### Encoding Hints

- [kVTCompressionPropertyKey_ExpectedFrameRate](videotoolbox/kvtcompressionpropertykey_expectedframerate.md)
- [kVTCompressionPropertyKey_MaximumRealTimeFrameRate](videotoolbox/kvtcompressionpropertykey_maximumrealtimeframerate.md)
- [kVTCompressionPropertyKey_PrioritizeEncodingSpeedOverQuality](videotoolbox/kvtcompressionpropertykey_prioritizeencodingspeedoverquality.md)
- [kVTCompressionPropertyKey_ReferenceBufferCount](videotoolbox/kvtcompressionpropertykey_referencebuffercount.md)
- [kVTCompressionPropertyKey_SourceFrameCount](videotoolbox/kvtcompressionpropertykey_sourceframecount.md)
- [kVTCompressionPropertyKey_SuggestedLookAheadFrameCount](videotoolbox/kvtcompressionpropertykey_suggestedlookaheadframecount.md)