MovieLabs has developed specifications to help studios and retailers to create interactive experiences that allows user to navigate and view main features and additional media. Collectively, these specifications are collectively called Cross Platform Extras (CPE).
Highlights from the NBCU hosted "NextGen" event at the Electric Cinema, London, 10 March 2016
The essential pieces are
CPE-Manifest: defines data models with unambiguous encoding definitions that define the interrelationships between media elements. "Manifest" also defines structures for file delivery. CPE-Manifest includes companion specs for defining application data (CPE-AppData) and stle elements (CPE-Style).
CPE-HTML: defines an API between studios and retailers that supports portable interactivie experiences.
Interactivity Profiles: Specific instructions for use of the specifications in certain environments. Interactivity Profile 1 (IP1) defines most CPE-Manifest implementations.
Common Extras Menu Metadata represents another approach to 'extras' metadata. Common Extras Menu allows the specification of a simple menu-based interactive experience similar to DVD. This specifciation was never completed, but the ideas led to Media Manifest and CPE-Manifest.