These applications require a format for synchronizing different media types contained in a presentation, and standard formats for basic data types such as text and images. Work has already started on designing application-specific formats. If content providers start to produce synchronized multimedia content for the Web, the market for products to author, display, and serve this type of Web content will also grow. The key to a solution is to make individual elements of an HTML page addressable. For example, each paragraph in a document could have an individual identifier.
Declarative formats have well-known advantages over scripting languages.
For instance, script-based content is often hard to produce and maintain. Having to write a program in order to, say, express the synchronization of an audio track with a video track seems overly complicated. Moreover, it is easier to build automated tools for a declarative format than for a scripting language. Some of the most important contributions in this field have been made by several W3C member organizations. The ease of building converters can be very important in bringing synchronized multimedia presentations to the Web.