---
title: kVTCompressionPropertyKey_MaximumRealTimeFrameRate
framework: videotoolbox
role: symbol
role_heading: Global Variable
path: videotoolbox/kvtcompressionpropertykey_maximumrealtimeframerate
---

# kVTCompressionPropertyKey_MaximumRealTimeFrameRate

A value that specifies the maximum real time rate at which frames can be submitted to a compression session.

## Declaration

```swift
let kVTCompressionPropertyKey_MaximumRealTimeFrameRate: CFString
```

## Discussion

Discussion The frame rate is measured in frames per second. This property can be used to inform the encoder of the maximum rate that frames could be submitted to the encoder during realtime encoding.  This allows the encoder to configure itself to ensure this capability. This property can only be used when kVTCompressionPropertyKey_RealTime has been set to true. Unlike kVTCompressionPropertyKey_ExpectedFrameRate, this property informs the maximum possible rate that the compression session could see, not the average frame rate that is expected in normal operation. By default, the property has a value of zero indicating “unknown”.

## See Also

### Encoding Hints

- [kVTCompressionPropertyKey_ExpectedDuration](videotoolbox/kvtcompressionpropertykey_expectedduration.md)
- [kVTCompressionPropertyKey_ExpectedFrameRate](videotoolbox/kvtcompressionpropertykey_expectedframerate.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)