1. A system for playing media files on a media device comprising: means for delivering to a user an authorization to enable the user to play at least two different media files on the media device in accordance with the parameters of the authorization, wherein at least a portion of at least one of the media files resides on the media device at the time of play, the media files are encoded in a proprietary format, and to the extent the playing of the media files on the media device exceeds the parameters of the authorization, the playing is limited.