Plumi Metadata

In the future Plumi will be shipping with the  Transmission Metadata Standard. This standard is still under development. The most recent draft can be  downloaded here

If you are a developer you can modify these fields to suit your needs by subclassing to make a new content type with specific new elements (the schema) in  http://dev.plone.org/collective/browser/ATVideo/branches/engage/content/engage.py

Before starting subclassing you should read -  http://plone.org/documentation/tutorial/archgenxml-getting-started

Also check -  http://plone.org/documentation/faq/custom-types