... everything is publicly available and can be googled here is some results of quick search https://www.dpreview.com/forums/thread/4566327 https://www.fastcinemadng.com/info/dng/pgm-to-dng-converter.html https://github.com/fastvideo/pgm2dng https://github.com/horshack-dpreview/OctaveRawTools https://www.dpreview.com/forums/post/65037078 also useful = https://github.com/Fimagena/raw2dng N/A reply
everything is publicly available and can be googled
here is some results of quick search
https://www.dpreview.com/forums/thread/4566327
https://www.fastcinemadng.com/info/dng/pgm-to-dng-converter.html
https://github.com/fastvideo/pgm2dng
https://github.com/horshack-dpreview/OctaveRawTools
https://www.dpreview.com/forums/post/65037078
also useful = https://github.com/Fimagena/raw2dng