Recipe 23.3. Making Animated, Interactive, and Visually Complex Movies Accessible

Problem

You want to make an animated, interactive, or visually complex movie accessible.

Solution

Hide animated and visually complex content from screen readers, and replace it with meaningful text alternatives. Or, create an alternative movie with an accessibility friendly architecture. Design the movie so that users relying on assistive technologies can navigate to and control the duration of content display.

Discussion

Most assistive technologies were developed to make documents accessible. HTML, word processor, and even XML documents are static; they have a beginning, a middle, and an end, and they exist as discrete documents, distinguishable from other documents. The user loads them on the screen, accesses their content, and when finished, moves on to the next document.

This document-based user experience, and the architecture it implies, while possible in Flash, is certainly not the norm. Designed for providing rich user experiences, Flash movies are often dynamic, with the contents changing constantly, as part of a pre-designed animation or even in live response to user activity. Indeed, these constant changes are often a part of the content. Unfortunately, this content is different enough from the static page-based documents that it is not practically accessible using many assistive technologies.

One example of the kinds of problems Flash content can cause occurs in screen readers in animated movies. Screen readers start at the top of each document and read from top to bottom. Unfortunately, every time a Flash movie changesin every frame during an animationthe screen reader starts over. At 12 frames per second, the screen reader gets trapped, indicating that the page is loading over and over again.

A similar issue occurs when users cannot control the speed at which information is presented. For example, in one popular advertising technique, two or three words of text appear at a time, fade away, and are replaced by a couple more words, and so on until the full text has been displayed. For users who can see and read the text, the animated text is usually paced well for comprehension and impact. But for users relying on assistive devices, the content may go by faster than the device can render it. The effect for users relying on these technologies is something like people with sight experience when television or movie credits scroll by so quickly that they can't read them.

Still another issue occurs with visually complex animations of relationships. For example, consider the case of a chart depicting the water cycle in which water rains, flows to rivers, empty into the ocean, and eventually evaporates into the atmosphere again. Providing alternate text descriptions for each of the graphic objects will hardly convey the meaning to a user relying on a screen reader.

The greatest challenge when making objects truly accessible is not technicalthe Accessibility panel makes the process quite simple. Rather, the challenge is providing content that is actually equivalent to the content shown on the stage.

The following list summarizes some of the techniques you can use to make complex and dynamic Flash content accessible:

• Group and/or hide objects selectively to maximize meaning. For example:

  Enclose animations in movie clip symbol instances, and provide text descriptions for the animation as a whole. Then, rather than exposing each element in the animation movie clip, hide all child elements from accessibility. With the animation movie clip instance selected, in the Description field of the Accessibility panel, enter a description of the animation as a whole unit. Describe not simply its visual details, but the relationship(s) between its components, or the progression of the animation over time.

  Ensure that text descriptions capture the meaning or substance of the animation or interaction, not simply the names of its visible assets.

• Use descriptions to reveal the structure of the document as a whole. Users with sight see the stage and perceive the relationship between the elementsnavigation, decoration, branding, main content, and so on. Use descriptions to communicate the screen's hierarchies and structural divisions, and provide cues as to how each of these divisions can be used or understood.

• Try to make your movies behave as much like documents as possible:

  Try to divide the movie into static screens that display, unchanging, for a sufficient amount of time to enable assistive devices to render the content.

  Give control to users. Provide a means of stopping, rewinding, and advancing through content in a self-paced way.

  If necessary, create an optimized-for- accessibility version of the movie. Use assistive technology detection to direct the user to this optimized version, as discussed in Recipe 23.1.

• Ensure that all navigational elements are accessible via the keyboard and the mouse, as discussed in Recipe 23.5.

In many cases, the more dynamic and user-aware your Flash movie is, the harder it is to make it accessible. Whether some creativity with the Accessibility panel is sufficient, you have to create a whole new Flash movie, or you are forced to offload accessible content to an HTML page, the key is to provide meaningful, organized content, and to ensure that users can navigate to it and spend as much time with it as they need.

See Also

Recipe 23.1, Recipe 23.5