Updates to iTunes Extras.
iTunes Extras Package Specification 5.2 Revision 4
The new video copy feature allows you to reuse source files already sent with the core feature film, as part of your Extras package. As a result, you do not need to re-deliver the video source when sending additional components, such as audio for a Director's Commentary.
When delivering additional components for your Extras package, copy the
<data_file role="source"> metadata block from the film metadata, and add it to your video gallery. The new component you deliver will then be associated with the source file. Upon delivery, the video source will be copied from the iTunes database and merged with your new component.
For more details, see the iTunes Extras Package Specification.
iTunes Extras Best Practices Guide
This new guide details the process of creating Extras, and outlines best practices in delivering them to iTunes.
To learn more, check out the iTunes Extras Best Practices Guide.