SMIL format: an easy way to create an awesome presentation

The SMIL format can help a person to create a presentation, by integrating independent multimedia objects and synchronizing them. SMIL allows it’s users to define the behavior of the presentation in time, describe how the presentation will look on the screen and associate hyperlinks to the media objects.

Basically, the SMIL documents are of XML 1.0 type, so if you want to learn how to use SMIL, it’s best to first learn XML.

A SMIL document is made of two parts: the head and the body of the document.

The head element contains information that doesn’t refer to the temporal behavior of the presentation.  It is formed of three parts: the layout information, meta information and switch information. The layout represents the position of the elements on a surface. Meta is used for defining the properties of a SMIL document. Switch is used for allowing the user to choose from many different choices, similar to the switch statement in C.

The body element contains the information about the behavior of the document in time and linking. It can contain a great variety of elements, starting from images, audio and video, and ending with programming functions like switch, text stream, etc. The timing for the content is being made by using another element, the par element. The elements of the body can overlap in time, so be careful when computing it. The most complicate element is the timing. One can present an element with three simultaneous time values: implicit, explicit and desirable time. So, the object itself has an implicit time of beginning and end, in its properties. The explicit values of beginning and end are the values used in the SMIL document itself, and the desirable values of the beginning and end are the values viewed by the user itself.