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On Windows 10 N, the windows media foundation and player are missing and QCameraInfo::availableCameras(); returns empty list. The mediaservice plugins are copied correctly both dsengine.dll and wmfengine.dll. The app works on other windows machines. You can try it blinkingmatters.com Qcamera object is defined, the empty list is not returned because of that issue.

Which dlls I need to add to my deployment to get qt multimedia to return correct list of cameras? I tried to coppied all dlls from windows/system32 which starts with "mf" mf*.dll without success. At least once I catch even a crash caused by Access violation (Code: c0000005). I am using precompiled qt library 5.12.0 64bit msvc2017 so I do not know more, with the stack trace:

Qt5Core!QString::QString

dsengine

Qt5Multimedia!QMediaServiceProviderHint::device

Qt5Multimedia!QCameraInfo::availableCameras

Andrej Fogelton
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1 Answers1

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Windows 10 N comes with no Media Foundation. You cannot (not allowed to) copy system32 DLLs to resolve the problem, instead the system needs a Media Feature Pack installed to make the Media Foundation APIs available.

Roman R.
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  • the user has no admin rights usually in a corporate environment, it is not allowed to redistribute media feature pack dlls? can you link a license? – Andrej Fogelton May 18 '19 at 16:21
  • It is not a question of missing DLLs. N versions have certain media APIs excluded from baseline version. You cannot compensate this by redistribution and even though I did check the LA I'd be surprised that it would assume one can redist a core OS subsystem as a redistributable. Media Feature Pack needs OS integration and will reboot the system to complete it. Lack of admin rights means that user cannot install the pack, cannot use the media features. – Roman R. May 18 '19 at 16:26