I'm trying to find some application that allows me to easily add/modify metadata for various files such as PDF, MKV, DOCX, MP3, PNG, JPG etc.
All these types of files (and a lot more) support metadata natively, so metadata can be added and then searched using various programs across various platforms. Of course I've found a myriad of programs that will modify graphics and music files but nothing that also allows me to edit say PDF or DOC files – I have to us a specific PDF or DOC program to update those types of files.
I don't want to use something like Google Desktop (reliant on a central database it makes) or some Windows/Mac only filesystem tagging.
I had thought Benubird might be the answer but that doesn't seem to do it (they said they were working on it but that was 3 years ago I think).