---
title: QCPortAttributeDefaultValueKey
framework: quartz
role: symbol
role_heading: Global Variable
path: quartz/qcportattributedefaultvaluekey
---

# QCPortAttributeDefaultValueKey

The key for the port default value. You can use this key only for value ports (Boolean, Index, Number, Color and String).

## Declaration

```swift
let QCPortAttributeDefaultValueKey: String
```

## See Also

### Constants

- [QCCompositionAttributeBuiltInKey](quartz/qccompositionattributebuiltinkey.md)
- [QCCompositionAttributeCategoryKey](quartz/qccompositionattributecategorykey.md)
- [QCCompositionAttributeCopyrightKey](quartz/qccompositionattributecopyrightkey.md)
- [QCCompositionAttributeDescriptionKey](quartz/qccompositionattributedescriptionkey.md)
- [QCCompositionAttributeHasConsumersKey](quartz/qccompositionattributehasconsumerskey.md)
- [QCCompositionAttributeIsTimeDependentKey](quartz/qccompositionattributeistimedependentkey.md)
- [QCCompositionAttributeNameKey](quartz/qccompositionattributenamekey.md)
- [QCCompositionCategoryDistortion](quartz/qccompositioncategorydistortion.md)
- [QCCompositionCategoryStylize](quartz/qccompositioncategorystylize.md)
- [QCCompositionCategoryUtility](quartz/qccompositioncategoryutility.md)
- [QCCompositionInputAudioPeakKey](quartz/qccompositioninputaudiopeakkey.md)
- [QCCompositionInputAudioSpectrumKey](quartz/qccompositioninputaudiospectrumkey.md)
- [QCCompositionInputDestinationImageKey](quartz/qccompositioninputdestinationimagekey.md)
- [QCCompositionInputImageKey](quartz/qccompositioninputimagekey.md)
- [QCCompositionInputPaceKey](quartz/qccompositioninputpacekey.md)