MPEG-4 Book, The

3.1. Object Descriptors: Entry Points to MPEG-4 Content

Part 2 [MPEG-4-2] and Part 3 [MPEG-4-3] of the MPEG-4 standard (corresponding to Chapters 8 to 12 in this book) specify the coding tools to generate compressed audio and visual streams. Each semantic visual or audio object may be coded into one or more such streams. An MPEG-4 presentation that consists of multiple such objects (and, hence, many streams) needs mechanisms to describe all the objects in the presentation. One part of this mechanism is embodied in the object descriptor framework [MPEG-4-1, Clause 8]. All components of an MPEG-4 presentation are discovered recursively through object descriptors (ODs). The details of this approach are explained in this chapter.

Object description ...