Mullender, K.S. (Sjoerd)

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GRiNS (formerly CMIFed)—A GRaphical iNterface for SMILSjoerd MullenderCWI (Centrum voor Wiskunde en Informatica)P.O. Box 94079NL-1090 GB Amsterdam, The NetherlandsSjoerd.Mullender@cwi.nlSMILThe Synchronized Multimedia Integration Language(SMIL, pronounced “smile”) was adopted as a W3Crecommendation in June of 1998. SMIL is a simple-to-author language to describe multimedia presentationsfor Web delivery. SMIL is an application of XML.SMIL provides Web users with:• Easily defined basic timing relationships• Fine-tuned synchronization• Spatial layout• Hyperlink support for time-based media• Ability to adapt to varying user and system charac-teristicsA SMIL document is a hierarchy of sequential, parallel,and switch nodes. Children of a sequential node areplayed sequentially; children of a parallel node areplayed in parallel; only one child of a switch node isplayed, depending on user and system characteristics.The hierarchy gives a rough timing relationship betweennodes which can be fine-tuned by the use of explicitbegin and end relationships.GRiNSGRiNS (GRaphical iNterface for SMIL) is a tool forauthoring and playing SMIL documents. While SMIL isa very simple-to-author language, creating and main-taining larger scale documents requires a more powerfultool than a text editor. The GRiNS authoring systemprovides an integrated editing and previewing tool (theonly one available) for SMIL. The tool allows the user,among other things, to create and view the hierarchicalstructure of a document, to create and view the explicittiming relationships, to create and view the spatial lay-out of the document, and to create and view hyperlinks.There are four main views on the document inGRiNS, as follows.The Presentation View is used to play the documentand to edit the spatial layout of the document. It is possi-ble to play the whole document from the beginning orplay only selected parts. The presentation view allowsthe user to start, pause, and stop the document usingVCR-like controls. The presentation view is also used toedit the spatial layout of image anchors.The Hierarchy View is the main editing view inGRiNS. In the hierarchy view it is possible to create newnodes, copy and paste subhierarchies, assign dataobjects to nodes etc. The document hierarchy estab-lishes the broader timing relationships between nodes.The Resource View displays the activities for eachscreen area and media resource along a timeline. Theview displays which media items get played when andin which region. Using the resource view the user canfine tune the hierarchy-defined timing.Using the Link View the user can view and define thehyperlinks within the document and to other documents.The view allows the user to select an anchor and viewall related anchors. The view also allows the user to seedangling anchors (anchors which are not the end pointof a hyperlink).History and ImplementationThe CMIFed project started in 1991 with the aim toinvestigate a new paradigm for the creation of multime-dia documents. From the start, the software for theproject was written in Python (Guido was the maindeveloper when the project started), and thus this projectis probably the oldest Python project in the world. In1994 the Chameleon project started with the aim todefine and implement multimedia authoring and presen-tation tools. CMIFed was used as a basis for this project.In early 1997 the W3C working group for SynchronizedMultimedia started with the aim to define a language forweb-based multimedia presentations. The work resultedin SMIL. As part of the development, CMIFed wasadapted to also be able to read and write SMIL docu-ments, and the system was renamed GRiNS.Currently, GRiNS consists of about 50,000 lines ofPython code plus a few extension modules. GRiNS runson Unix (SGI, Sun), Mac, and PC (Windows 95/98/NT).For More InformationFor more information on the GRiNS authoring and play-back system and to download the GRiNS playback sys-tem, see the GRiNS home page at http://www.cwi.nl/GRiNS/.For more information about the Chameleon project,and for published papers about CMIFed and the theoret-ical background of the project, see http://www.cwi.nl/Chameleon/.

GRiNS (formerly CMIFed) - A GRaphical iNterface for SMIL

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