The unmodified advanced demo from 1.4 is fine using either camera. From my project:
[2016.02.02-22.18.40:485][595]ARToolkit: BisonCam, NB Pro
[2016.02.02-22.18.40:485][595]ARToolkit: Device path: \\?\usb#vid_5986&pid_014c&mi_00#7&a9de3d&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global
[2016.02.02-22.18.40:485][595]ARToolkit: Logitech HD Webcam C615
[2016.02.02-22.18.40:485][595]ARToolkit: Device path: \\?\usb#vid_046d&pid_082c&mi_02#6&88cf4eb&0&0002#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\{bbefb6c7-2fc4-4139-bb8b-a58bba724083}
[2016.02.02-22.18.40:485][595]ARToolkit: Number of webcams: 2
[2016.02.02-22.18.40:485][595]ARToolkit: Init started
[2016.02.02-22.18.47:202][595]ARToolkit: Camera resolution (960,720)
[2016.02.02-22.18.47:202][595]ARToolkit: Camera pixel format: 1
[2016.02.02-22.18.47:205][595]ARToolkit: Video texture created (960,720)
[2016.02.02-22.18.47:205][595]ARToolkit: Param load start
[2016.02.02-22.18.47:205][595]ARToolkit: Param load success
[2016.02.02-22.18.47:205][595]ARToolkit: Camera init succesfull!
[2016.02.02-22.18.47:308][595]ARToolkit: AR Patt Handle created
[2016.02.02-22.18.47:308][595]ARToolkit: 3D Handle created
[2016.02.02-22.18.47:308][595]ARToolkit: ARToolkit init succesfull!
[2016.02.02-22.18.47:308][595]ARToolkit: NFT init started...
[2016.02.02-22.18.47:308][595]ARToolkit: Using NFT tracking settings for more than one CPU.
[2016.02.02-22.18.47:308][595]ARToolkit: NFT init successfull...
[2016.02.02-22.18.47:474][595]ARToolkit: Init complete !!
[2016.02.02-22.18.47:475][595]LogBlueprintUserMessages: [ARToolkitBaseAdvanced_C_1] 960x720
[2016.02.02-22.18.47:475][595]ARToolkit: Reading C:/Users//Documents/Perforce/ChoreoAR/Content/ARToolkit/Data/patt.Hiro
[2016.02.02-22.18.47:475][595]ARToolkit: Hiro loaded
[2016.02.02-22.18.47:475][595]ARToolkit: Reading C:/Users//Documents/Perforce/ChoreoAR/Content/ARToolkit/Data/patt.Kanji
[2016.02.02-22.18.47:475][595]ARToolkit: Kanji loaded
[2016.02.02-22.18.47:475][595]ARToolkit: Reading C:/Users//Documents/Perforce/ChoreoAR/Content/ARToolkit/Data/patt.sample1
[2016.02.02-22.18.47:476][595]ARToolkit: sample1 loaded
[2016.02.02-22.18.47:476][595]ARToolkit: Reading C:/Users//Documents/Perforce/ChoreoAR/Content/ARToolkit/Data/patt.sample2
[2016.02.02-22.18.47:476][595]ARToolkit: sample2 loaded
[2016.02.02-22.18.47:476][595]PIE: Info Play in editor start time for /Game/Maps/UEDPIE_0_ARToolkitAdvanced 6.394
[2016.02.02-22.18.47:477][595]LogBlueprintUserMessages: Late PlayInEditor Detection: Level '/Game/Maps/ARToolkitAdvanced.ARToolkitAdvanced:PersistentLevel' has LevelScriptBlueprint '/Game/Maps/ARToolkitAdvanced.ARToolkitAdvanced:PersistentLevel.ARToolkitAdvanced' with GeneratedClass '/Game/Maps/ARToolkitAdvanced.ARToolkitAdvanced_C' with ClassGeneratedBy '/Game/Maps/ARToolkitAdvanced.ARToolkitAdvanced:PersistentLevel.ARToolkitAdvanced'
[2016.02.02-22.18.47:802][595]LogCrashTracker:
[2016.02.02-22.18.55:931][595]LogCrashTracker:
[2016.02.02-22.18.55:931][595]LogWindows:Error: === Critical error: ===
Fatal error!
Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x8a8d1004
UE4Editor-ARToolkitPlugin.dll!arLabelingSubDBR3C()
UE4Editor-ARToolkitPlugin.dll!arDetectMarker()
UE4Editor-ARToolkitPlugin.dll!FARToolkitDevice::DetectMarkers() [d:\unreal projects\arpluginv14\plugins\artoolkitplugin\source\artoolkitplugin\private\artoolkitdevice.cpp:1013]
UE4Editor-ARToolkitPlugin.dll!FARToolkitDevice::UpdateDevice() [d:\unreal projects\arpluginv14\plugins\artoolkitplugin\source\artoolkitplugin\private\artoolkitdevice.cpp:174]
UE4Editor-Engine.dll!UActorComponent::ConditionalTickComponent() [c:\users\\documents\github\unrealengine\engine\source\runtime\engine\private\components\actorcomponent.cpp:1139]
UE4Editor-Engine.dll!FActorComponentTickFunction::ExecuteTick() [c:\users\\documents\github\unrealengine\engine\source\runtime\engine\private\components\actorcomponent.cpp:679]
UE4Editor-Engine.dll!FTickFunctionTask::DoTask() [c:\users\\documents\github\unrealengine\engine\source\runtime\engine\private icktaskmanager.cpp:141]
I have removed the NFT marker load loop and don’t Get Marker for NFT.
I’ve been unable to recreate the crash in the demo by making my changes but will keep investigating.