VizAudio

From Humanitarian FOSS Summer Institute 2009

The VizAudio project is an attempt to make the GNOME desktop more accessible to deaf users.

1 About
2 Technology Overview
- 2.1 Example Workflow
3 Team
4 Files
5 Links

About

Visual audio will be the next major step for a11y in open source...
—Unknown

VizAudio is a new library, proposed to be included in the GNOME core. The idea behind VizAudio is to create a plug-in framework to allow developers to create direct links between audio events and visual events. VizAudio is extremely important to users who are hearing impaired. For example, if an instant messaging client plays a sound when a message is received, the screen might flash to indicate to a deaf user that an event of interest has occurred.. We must also keep in mind that a large portion of the hearing impaired also suffer visual impairments, so ideally these effects will be user-customizable through a graphical user interface. The project has no existing code and could function as a library to be used by developers or a framework for plug-in development on existing applications. We will rely heavily upon the tools provided by libcanberra, a library for audio handling, and GTK, a library to build user interfaces in GNOME. We hope to create an extensible, maintainable solution that can become a standard feature for GNOME and/or accessibility developers in general.

Technology Overview

The VizAudio project has two components currently:

libvizaudio: a library of visual effects, written in C and dependent upon GTK.
libcanberra: an existing audio library modified (by HFOSS interns) to use visual effects rather than audio effects. See libcanberra.

Example Workflow

Application calls a function in libcanberra to play a sound, passing it some information about the sound it would like to play. This information may include properties for visual effects, or it may not.
libcanberra will play a sound using this information and one of the available audio backends. If a Gconf flag for libvizaudio is enabled and libvizaudio is installed, the system will display a visual effect. The type of visual effect depends upon whether or not the developer specifies any visual effect data.