Originally Posted by kiwidude
@travger - I'm afraid the only way I can think of doing this as a plugin would mean you would have to use the plugin exclusively when you add books. So no more drag/dropping formats onto the book details pane, library view or edit metadata dialogs, no more using the built-in toolbar button, no using copy to library etc. I think that is too limiting to be something of general interest. If it was going to be implemented it really needs imho to be in the core Calibre add code, which means you would need to raise a feature request via the bug tracker.
Maybe some signal could be implemented which could be hooked into, but again that is a core calibre change.
There is an other way.
But has a drawback.
You could do two things:
1. Tell calibre to use filename for metadata-info and add filename as title.
2. Tell calibre to use filename for metadata-info and add filename in a field you define.
Drawback of both options is, that it is not possible (as far as I know) to use this option in combination with the get metadata from metadata-file
So in case 1 you would have an unknown author
in case 2 you would have an unknown author and unknown title
If you use case 2, you could mass edit your files with a regex and than afterwards get all info you would get from file names.
But, it would be nice to have a feature to do this OR to have the option to fill unknown info from file metadata OR to have the option of mass-edit fetch metadata from file (but this could take a lot of time when mass editing a lot of files)