A new and easy-to-use language that will merge television and the World Wide Web has been developed by an industrial-academic alliance. If adopted as a standard, it will enable high-quality multimedia content on the Internet, Tim Greenhalgh writes.
Last Thursday, the web standards body, the World Wide Web Consortium announced the first public working draft of Synchronised Multimedia Integration Language (SMIL; pronounced "smile").
SMIL enables authors to bring television-like content to the Web, avoiding the limitations of traditional television and significantly lowering the bandwidth requirements for transmitting this type of content over the Internet.
SMIL documents can be authored using a simple text editor, following the model of HTML.
"SMIL will have the same effect for synchronised multimedia as HTML had for hypertext," said Philipp Hoschka, chair of the W3C Synchronised Multimedia Working Group and editor of the SMIL specification.
SMIL was developed by the working group, a mix of experts from the four divergent industries - CD-Rom, interactive television, Web, and audio/video streaming - interested in bringing synchronised multimedia to the Web. The W3C SYMM Working Group includes leading research organisations such as Columbia University and INRIA and key industry players such as Digital Equipment Corporation, Lucent/Bell Labs, Microsoft, Netscape, Philips, RealNetworks and The Productivity Works.
Many standard television news broadcasts rewritten in SMIL would require far less bandwidth, by eliminating the need to convert low-bandwidth media types such as text and still images into high-bandwidth video. "SMIL avoids having to swamp the Internet with high-bandwidth video if you want to create television-like content," Dr Hoschka said.
The standard would, for example, allow producers to create cheap, effective and easily updated multimedia courseware, accessible worldwide. Users could view video, follow links, search topics and contact tutors.
SMIL FEATURES
* Temporal hyperlinking: offers all the capabilities of hyperlinks in HTML, and adds those required in time-based presentations.
* Reusability: multimedia presentation components are referenced via URLs rather than physically embedded into a SMIL file. For example, videos stored in a digital video library can be reused in many presentations.
* Load balancing: Different media objects in a presentation can be stored on different servers.
* Language selection: Authors can indicate audio track is available in several languages.
* Bandwidth selection: Authors can express that a media object such as an audio track is available in different versions, each having been encoded for a different transmission bandwidth. This guarantees presentations can be played even when only low bandwidth is available.
* Easy-to-learn "synchronisation primitives": 90 per cent of the power of SMIL can be tapped by mastering only two tags.