---
title: VTFrameProcessorError.Code.sessionAlreadyActive
framework: Video Toolbox
role: symbol
role_heading: Case
platforms: [iOS 6.0+, iPadOS 6.0+, Mac Catalyst 13.0+, macOS 10.8+, tvOS 10.2+, visionOS 1.0+]
path: videotoolbox/vtframeprocessorerror-swift.struct/code/sessionalreadyactive
---

# VTFrameProcessorError.Code.sessionAlreadyActive

An attempt is made to start a session that is already started.

## Declaration

```swift
case sessionAlreadyActive
```

## See Also

### Enumeration Cases

- [VTFrameProcessorError.Code.fatalError](videotoolbox/vtframeprocessorerror-swift.struct/code/fatalerror.md)
- [VTFrameProcessorError.Code.initializationFailed](videotoolbox/vtframeprocessorerror-swift.struct/code/initializationfailed.md)
- [VTFrameProcessorError.Code.invalidFrameTiming](videotoolbox/vtframeprocessorerror-swift.struct/code/invalidframetiming.md)
- [VTFrameProcessorError.Code.invalidParameterError](videotoolbox/vtframeprocessorerror-swift.struct/code/invalidparametererror.md)
- [VTFrameProcessorError.Code.memoryAllocationFailure](videotoolbox/vtframeprocessorerror-swift.struct/code/memoryallocationfailure.md)
- [VTFrameProcessorError.Code.processingError](videotoolbox/vtframeprocessorerror-swift.struct/code/processingerror.md)
- [VTFrameProcessorError.Code.revisionNotSupported](videotoolbox/vtframeprocessorerror-swift.struct/code/revisionnotsupported.md)
- [VTFrameProcessorError.Code.sessionLevelError](videotoolbox/vtframeprocessorerror-swift.struct/code/sessionlevelerror.md)
- [VTFrameProcessorError.Code.sessionNotStarted](videotoolbox/vtframeprocessorerror-swift.struct/code/sessionnotstarted.md)
- [VTFrameProcessorError.Code.unknownError](videotoolbox/vtframeprocessorerror-swift.struct/code/unknownerror.md)
- [VTFrameProcessorError.Code.unsupportedInput](videotoolbox/vtframeprocessorerror-swift.struct/code/unsupportedinput.md)
- [VTFrameProcessorError.Code.unsupportedResolution](videotoolbox/vtframeprocessorerror-swift.struct/code/unsupportedresolution.md)