This specification defines the Document Object Model (DOM) specification for synchronized multimedia functionality [SMIL-DOM]. It is part of work in the Synchronized Multimedia Working Group (SYMM) towards a next version of the SMIL language and SMIL modules. Related documents describe the specific application of this SMIL DOM for SMIL documents and for HTML and XML documents that integrate SMIL functionality. The SMIL DOM builds upon the DOM Core functionality, adding support for timing and synchronization, media integration and other extensions to support synchronized multimedia documents.