Extensions to the SMIL multimedia language

Abstract

The goal of this work has been to extend the Synchronized Multimedia Integration Language (SMIL) to study the capabilities and possibilities of declarative multimedia languages for the World Wide Web (Web). The work has involved design and implementation of several extensions to SMIL.

A novel approach to include 3D audio in SMIL was designed and implemented. This involved extending the SMIL 2D spatial model with an extra dimension to support a 3D space. New audio elements and a listening point were positioned in the 3D space. The extension was designed to be modular so that it was possible to use it in conjunction with other XML languages, such as XHTML and Scalable Vector Graphics (SVG) language.

Web forms are one of the key features in the Web, as they offer a way to send user data to a server. A similar feature is therefore desirable in SMIL, which currently lacks forms. The XForms language, due to its modular approach, was used to add this feature to SMIL. An evaluation of this integration was carried out as part of this work.

Furthermore, the SMIL player was designed to play out dynamic SMIL documents, which can be modified at run-time and the result is immediately reflected in the presentation. Dynamic SMIL enables execution of scripts to modify the presentation. XML Events and ECMAScript were chosen to provide the scripting functionality.

In addition, generic methods to extend SMIL were studied based on the previous extensions. These methods include ways to attach new input and output capabilities to SMIL.

To experiment with the extensions, a Synchronized Multimedia Integration Language (SMIL) player was developed. The current final version can play out SMIL 2.0 Basic profile documents with a few additional SMIL modules, such as event timing, basic animations, and brush media modules. The player includes all above-mentioned extensions.

The SMIL player has been designed to work within an XML browser called X-Smiles. X-Smiles is intended for various embedded devices, such as mobile phones, Personal Digital Assistants (PDA), and digital television set-top boxes. Currently, the browser supports XHTML, SMIL, and XForms, which are developed by the current research group. The browser also supports other XML languages developed by 3rd party open-source projects.

The SMIL player can also be run as a standalone player without the browser. The standalone player is portable and has been run on a desktop PC, PDA, and digital television set-top box. The core of the SMIL player is platform-independent, only media renderers require platform-dependent implementation.