David I love the plugin and it looks very promising, but I seem to have a problem.
I either am deficient in understanding how to use the feature, or there is some other reason it doesn't work as the documentation describes. I have carefully read and re-read all the documentation I could find that seems relevant. I have tried it with a new wordpress installation with only the MLA plugin enabled to eliminate any kind of plugin interaction possibility.
I have a collection of only PDF files, all "purely" authored in latest version of Adobe Acrobat Pro CS6, so the PDF files themselves are as canonical I think as possible. Each has had metadata input using Acrobat. I have confirmed that Acrobat shows this metadata both in the first Acrobat 'Document Info' screen, and echoed to its 'Additional Metadata' button/tabs that are supposed to somehow use XML to handle both EXIF and IPTC fields. I have also verified the presence of the metadata using the independent PDFtk command line tool (q.v.:)
( http://www.pdflabs.com/docs/pdftk-man-page )
My point is the metadata is filled in everywhere I can find that it should be and I can demonstrate it's in these PDF files somewhere!
I cannot FOR THE LIFE of me figure out any mode or method to get the MLA to see any of that metadata in any of those PDF attachments, either during upload or using the MLA IPTC/EXIF tab to any standard Wordpress field or Category or Tag fields.
I am intrigued by the ALL_EXIF and ALL_ITPC fields, but I can't figure out from the documentation how I would use them to see this metadata in the PDF files: an example expressed as an [MLA-GALLERY] shortcode would be most appreciated.
SUMMARY: Demonstrably populated EXIF (and/or) ITPC metadata fields in a latest version Adobe-created PDF file, but seemingly unable to see that metadata using MLA plugin with any method I've discovered (so far).
Any ideas? I'm looking forward to slapping myself in the forehead over something cravenly simple.
http://wordpress.org/extend/plugins/media-library-assistant/