This specification defines the third version of the Synchronized Multimedia Integration Language (SMIL, pronounced "smile"). SMIL 3.0 has the following design goals: (1) Define an XML-based language that allows authors to write interactive multimedia presentations. Using SMIL 3.0, an author may describe the temporal behavior of a multimedia presentation, associate hyperlinks with media objects and describe the layout of the presentation on a screen. (2) Allow reusing of SMIL 3.0 syntax and semantics in other XML-based languages, in particular those who need to represent timing and synchronization. For example, SMIL 3.0 components are used for integrating timing into XHTML and into SVG. (3) Extend the functionalities contained in the SMIL 2.1 into new or revised SMIL 3.0 modules. (4) Define new SMIL 3.0 Mobile Profiles incorporating features useful within the industry. SMIL 3.0 is defined as a set of markup modules, which define the semantics and an XML syntax for certain areas of SMIL functionality.