SMIL

Smil, or SMIL, stands for Synchronized Multimedia Integration Language, a markup language defined by the World Wide Web Consortium (W3C) for authoring multimedia presentations. SMIL documents describe the timing, layout, and behavior of media elements such as audio, video, text, and images, enabling them to be synchronized and organized on a timeline. The language is XML-based and provides constructs to control how media is presented, including regions for layout and containers such as seq for sequential playback and par for parallel playback. Timing semantics use attributes like begin, dur, end, and repeat to coordinate playback across different media elements.

SMIL was developed as part of the W3C’s multimedia framework in the late 1990s and has undergone several revisions, including SMIL 2.x specifications. Although not tied to a single platform, SMIL documents can be rendered by compatible players on various operating systems and devices. In practice, SMIL has been used for digital signage, e-learning modules, and television broadcast graphics, where precise control over timing and layout is important. In web development, SMIL support has varied across browsers, and HTML5, CSS, and JavaScript have largely supplanted it for many web-based applications. Nevertheless, SMIL remains relevant in certain domains and is supported by some media players and authoring tools.

Related concepts include timed text and other multimedia markup languages.