out.pdf has the same number of pages as in.pdf but all pages are blank. In addition, pdftopdf emits a message "ERROR: Weird page contents" for each page. This message is visible in the error_log wgen pdftopdf is run by CUPS.
The problem happens only with the pdftopdf CUPS filter and not with the pdftops CUPS filter which is also based on Poppler.
I have seen two error_logs now (from ilna and from a duplicate) and I have also tested by myself running the pdftopdf filter on the command line:
/usr/lib/ cups/filter/ pdftopdf 1 1 1 1 '' in.pdf > out.pdf
out.pdf has the same number of pages as in.pdf but all pages are blank. In addition, pdftopdf emits a message "ERROR: Weird page contents" for each page. This message is visible in the error_log wgen pdftopdf is run by CUPS.
The problem happens only with the pdftopdf CUPS filter and not with the pdftops CUPS filter which is also based on Poppler.