1. A method, comprising: enabling authoring of a media set; enabling selection of a first independent media element, associated with a first entity, as a principal media element; enabling selection of at least a second independent media element, associated with a second entity, as a supplemental media element; extracting principal media metadata from the principal media element; determining properties of the principal media element; generating a principal media profile representing the principal media metadata and properties; and extracting and analyzing content of the principal media element, using as inputs, the principal media element, the principal media profile, and at least some results of media compositing; generating a principal media timeline, which is an outline representation of the extracted and analyzed content of the principal media element, including relationship information between the content; and enabling presenting of the first and second media elements together as the media set in a synchronous manner using a relative virtual time code, wherein said relative virtual time code includes an intermediary data structure containing a collection of patterns and time-based relationships used to generate an absolute time code for variations of the media elements in the synchronous media set and wherein said absolute time code includes a fixed time code for specific instances of the media elements in the synchronous media set, wherein said authoring of the media set includes: selecting the first media element as said principal media element; selecting or creating the second media element as said supplemental media element; performing media compositing to relate presentation of the principal and supplemental media elements to each other; generating a portable media project file that contains results of the media compositing; generating a portable media compositing file from the portable media project file; and publishing the portable media compositing file, the portable media compositing file being usable to allow presentation of the media set in the synchronous manner.