Patent ID: 8280051

Claim:
A method, comprising: importing a media stream having an encrypted portion; decrypting said encrypted portion; encoding said media stream into digital content, wherein said encoding comprises: encrypting a first portion of that digital content, less than the entire digital content, said first portion being necessary for presentation of the media stream; and not encrypting a second portion of that digital content, less than the entire digital content, said second portion being necessary for conducting navigation operations on, without decrypting, the media stream represented by the digital content, wherein said digital content comprises a set of layers, each relatively higher-level layer representing an abstraction for which each relatively lower-level layer represents an implementation thereof; a first set of relatively higher-level layers represent audio or video information for the media stream, and a second set of relatively lower-level layers represent techniques by which that information is formatted or supplemented; and said encrypting is applied only to the first portion of the digital content representing audio and or video information.