so far, I know the current implementation of Studio for the extraction of the metadata is working only in the context of the UI as integral part of the Studio dev UI.
It seems that there is not a Studio library which could be used as standalone call - means to be called outside the Studio Dev environment. I believe, also such usage of the tool as standalone utility is not intended /supported by PTC
The supported way currently for customers to extract the data form PVZ to json is:
To use the Studio dev UI to load the pvz file to the upload folder and to create the json file by selecting the metadata check box (also multi file select) later the files could be used in other projects
Or to purchase some tools developed by third party company /PTC dev partners /which implements this task. You can also contact the PTC presale team. Possibly some PTC presales departments has already develop such tools which are offered as extras service.
Unfortunately, I could not find information about such officially supported PTC tools for the general use.
I checked also the pvsoptimize tools argument sbut seem that the Documents\VuforiaStudio\Projects\node_modules\cad-import-filters\import_filters\bin\pvsoptimize.exe -? or -H