Isn't it possible to store Metadata directly in GeoPDF files using GDAL command line tools (gdal_translate, gdal_edit) or GDAL Python?
Something like: gdal_edit -mo "CUTLINE=POLYGON(...)" orig.pdf
Unfortunately, all I can achieve is the creation of an additional *.aux.xml file that includes the Metadata entry (GDAL 2.2.2 Windows 64bit).
Using PyPDF2 to store the Metadata didn't help either, because gdalinfo couldn't read the data.
Do I miss something here?