The term rich media was coined to describe a broad range of digital interactive media. Rich media can be downloadable or may be embedded in a web page. If downloadable, it can be viewed or used offline with media players such as Real Networks' RealPlayer, Microsoft Media Player, or Apple's QuickTime, among others.
The defining characteristic of rich media is that it exhibits dynamic motion. This motion may occur over time or in direct response to user interaction.
Two examples of dynamic motion that occur over time are a streaming video newscast and a stock "ticker" that continually updates itself. An example of dynamic motion in response to user interaction is a prerecorded webcast coupled with a synchronized slide show that allows user control. Another is an animated, interactive presentation file embedded in a web page.
Elements of rich media are increasingly used in education, in areas ranging from distance learning to web-based teaching and instructional tools.
Not surprisingly, rich media presents numerous accessibility challenges. However, rich media can be made accessible if all the elements are developed with accessibility in mind and the end product is used or viewed on accessible media players. Accessible rich media typically includes captioning, audio description, and navigation using a keyboard.
Accessible media players are those that can be operated by all users, including those using screen readers. They must also provide authors with the means to add captions, audio descriptions, extended audio descriptions, and subtitles. The current level of accessibility for media players creates interesting situations. Some media players allow video descriptions to be created and played but have an inaccessible interface that users of screen readers cannot operate. This results in the primary audience for audio descriptions not being able to select the PLAY button.
Another issue is that captions may look different when created on one player and then played back on another. For instance, captions developed using QuickTime may look fine when viewed in QuickTime but then appear larger or smaller when later viewed in RealPlayer.
While much still needs to be resolved, considerable improvements in accessibility have been made. A free captioning and description tool, MAGpie , is now available for adding captions and audio description to video and audio files.
Several media players have also made considerable progress in improving accessibility of their products. To learn more about accessible rich media, visit the National Center for Accessible Media's Tools & Guidelines  web page. This web page includes a showcase of accessible rich media; tutorials on captioning audio, descriptive video, making maps and other forms of rich media accessible; strategies for dealing with player and cross-platform issues; links to tools for rich media authoring and viewing; links to latest news; and much more.
-  MAGpie
-  Tools & Guidelines