Sound Objects for SVG

International audienceA sound object can be defined as a time structure of audio chunks whose duration is on the time scale of 100 ms to several seconds. Sound objects have heterogeneous and time-varying properties. They are the basic elements of any format for Interactive Audio (IA). We have designed an XML language, A2ML, for Interactive Audio which offers, concerning the sequencing of sounds, a level of capabilities similar to that of iXMF, the interactive audio file format defined by the Interactive Audio Special Interest Group (IASIG). A2ML uses SMIL timing attributes to control the synchronization of sound objects and supports 3D sound rendering, DSP and positional parameters's animation, by embedding the SMIL animation module. Like in a traditional mixing console, mix groups can be used to regroup multiple sound objects and apply mix parameters to all of them at the same time. An API allows external control and dynamic instantiation of sound objects. As with graphics, a declarative language for interactive audio is much more powerful than a node-graph based approach implemented using an imperative language. The structured declarative model offers easier reuse, transformability, accessibility, interoperability and authoring. An XML declarative language for audio like A2ML could help to reach the goal of the IXMF workgroup, i.e. build a system by which composers and sound designers create an interactive soundtrack and audition it by simulating target application control input while working in the authoring environment. In this paper, we will show how an XML language for interactive audio can be used with SVG. After an introduction to the history of sound objects, we will use the example of a computational character with a simple orient behaviour to demonstrate the complementarity of SVG and A2ML. The best way to use these two languages is to synchronize them with a third one, a tag-value dispatching language. We will then present a complex application for which the use of both SVG and A2ML is natural, i.e. a navigation system for visually impaired people based on OpenStreetMap