fixml to flat convert

Imported from previous forum

Hi, Just moved to fixml world, and still having bunch of processing in
mvs, what would be the best scenario to flatten fixml files to be used
in mainframe processing (fixed length, predefined field length).

So far looking at cobol parse command, but surely should be other
options or third party utilities. Will appreciate you info.
What min set of info I can start?

Tx to all. Mario