SMIL is an acronym referring to the Synchronised Multimedia Integration Language. This language is an XML markup which is utilised for the description of multimedia. It is metadata that defines variables such as the timing, the layout, visual transitions, animations as well as the embedding of media. Because it is focused on media in general and not any particular form of it, it can be used in XML to define audio, images, video and even text. Furthermore, it is also capable of defining links to other multimedia on another server such as the embedding system that YouTube uses.
It was in 2001 that the W3C recommended the SMIL version2.0 to the web developers of the world. In this version 2 was the introduction of the structure of the language that allowed for the SMIL integration into XML and because of this it may also be referred to as XHTML+SMIL.
Then in 2005, version 2.1 was released along with several needed extensions that was developed through the years as cell phones became a popular web surfing tool. As a result, these extensions were created so that it could be utilised by the mobile phone’s Multimedia Messaging System.
Version 3 was submitted to the W3C for recommendation at the end of 2006 and on December it was approved which makes the most currently available version being that of SMIL 3.0.
The actual SMIL files feature a structure that is very similar to that of HTML in that it includes a head and body section. Like HTML, the SMIL head includes the metadata about the file and the body includes the definitions referring to things like timing and more. Furthermore, the SMIL file can be stored on a separate server and still be called upon so as to allow for the use of load balancing which is very important when dealing with a website that contains large amounts of multimedia. The files themselves though will feature a file extension of .smi or .smil but it is important to point out that the SAMI language also makes use of the .smi extension and therefore .smil is the one that should be used.
Basically, when there is media involved, SMIL can be used to make things run more efficiently than without it. The language has also been used in combination with both VoiceXML as well as MusicXML. This allows for one to create a webpage that is basically a slide show that also includes a voice over. Once again, the concept is the simultaneous combination of multiple multimedia streams.
While there are some W3C specifications that really serve no purpose for the average web visitor or developer, this is not one of them. Many handheld devices today are now implementing SMIL as part of their Multimedia Messaging System which is in all simplicity the same thing as SMS, just with multimedia rather then text. It is also the technology used in the development of HD DVD in order to allow for more advanced user interactivity.
Original Authors: Nick
Edit Update Authors: M.A.Harris
Updated On: 04/03/2009