Specifies the coded representation of the spatio-temporal positioning of audio-visual objects as well as their behavior in response to interaction (scene description); the Extensible MPEG-4 Textual (XMT) format, a textual representation of the multimedia content described in ISO/IEC 14496 using the Extensible Markup Language (XML); and a system level description of an application engine (format, delivery, lifecycle, and behavior of downloadable Java byte code applications).