Read all OpenPose json files and create single tab separated file for pose_keypoints_2d for single person

The script uses some Windows commands: dir and mkdir. These can be replaced with e.g. linux commands ls and mkdir. The script requires the name of a root folder and the name of a subfolder of the root folder, for example:

FinalDataset 20220916 

The script searches for a folder that contains files with the extension '.json' under the subfolder. These files can be in the subfolder itself. The output is in a folder keypoints.tab and would be called keypoints.tab/20220916.tab

usage:

bracmat "get$\"jsn2tab.bra\"" <root> <subfolder> 

Without the last two arguments, their values are taken from the lines

(Root=FinalDataset) (meetings=20220916) 

in the script.

The Bracmat interpreter can be obtained from https://github.com/BartJongejan/Bracmat