Accessibility and Collated Text Transcript

  1. Do You Need Multimedia?
  2. Accessibility Concerns
  3. Equivalent Information
  4. Captioning
  5. Collated Text Transcripts
  6. Auditory Description
  7. Referencing Equivalent Information
  8. Is Text Enough?

Do You Need Multimedia?

Earlier in the lessons I urged you consider whether or not you needed to include multimedia objects on your web pages; just because you can do something does not mean that you should. Sometimes a multimedia object is the best way to convey the message to your target audience but you should take the necessary steps to avoid alienating your visitors who could potentially have accessibility issues with multimedia objects. Care should be taken to plan for those visitors who may not be able to view the site as you intended them to view it.

Accessibility Concerns

Here is a quick list about the major accessibility issues concerning multimedia objects:

Currently, the number one problem is that few developers are providing equivalent information for multimedia they include in their pages. Because of this, good web developers should ensure that all multimedia objects include equivalent information.

Equivalent Information

Content is "equivalent" to other content when both fulfill essentially the same function or purpose upon presentation to the user. For example, consider a repeating animation that shows cloud cover and precipitation as part of a weather status report. Since the animation is supplementing the rest of the weather report, which is already presented in natural language i.e. plain text, a less verbose description of the animation is necessary. However, if the animation appears in a classroom setting where students are learning about cloud formations in relation to land mass, then the animation ought to be described for those who cannot view the animation but who also want to learn the lesson.

Note that equivalent information focuses on fulfilling the same function. Providing equivalent information for inaccessible content is one of the primary ways developers can make their pages more accessible to people with disabilities.

As part of fulfilling the same function of content an equivalent may involve a description of that content (i.e., what the content looks like or sounds like). For example, in order for users to understand the information conveyed by an interactive chart, developers should describe the visual information in the chart.

Since text content can be presented to the user as synthesized speech and Braille as well as visually-displayed text, equivalents must be written so that they convey all essential content. Non-text equivalents (e.g., an auditory description of a visual presentation, a video of a person telling a story using sign language as an equivalent for a written story, etc.) also improve accessibility for people who cannot access visual information or written text, including many individuals with blindness, cognitive disabilities, learning disabilities, and deafness.

Captioning

Captioning is a text transcript for the audio track of a video presentation that is synchronized with the video and audio tracks. Captions are generally rendered visually by being superimposed over the video which benefits people who are deaf and hard-of-hearing and anyone who cannot hear the audio.

Collated Text Transcripts

A collated text transcript combines (collates) captions with text descriptions of video information (descriptions of the actions, body language, graphics, and scene changes of the video track). These text equivalents make presentations accessible to people who are deaf or blind and to people who cannot play movies, animations, etc. It also makes the information available to search engines. The collated text transcript is the most useful and robust of the text equivalents. A text transcript can be made available as a simple XHTML file or even as a plain text file (TXT).

Auditory Description

One example of a non-text equivalent is an auditory description of the key visual elements of a presentation. The description is either a prerecorded human voice or a synthesized voice (recorded or generated on the fly). The auditory description is synchronized with the audio track of the presentation, usually during natural pauses in the audio track. Auditory descriptions include information about actions, body language, graphics, and scene changes.

Referencing Equivalent Information

Let's look at a couple of ways to reference equivalent information along with your embedded media file. In this case, let's use a text transcript. We can reference our text transcript file as follows:

Use of "[D]" for "description" as a discreet way of referring to a text alternative is supported by NCAM and the W3C.

Is Text Enough?

Web AIM, an organization devoted to supporting the accessibility of the web, argues that in most cases text alone is not enough. Read Design Considerations - Text-only Versions for their perspective on when text is sufficient and insufficient on the web.

Providing equivalents for multimedia objects can be a lot of work but you will end up with more valuable assets in the end. Having a collated text transcript for all of the multimedia objects on your page should not be hard because you should already have that information from the scripts and storyboards that you used in the creation of your multimedia pieces.

Now that you are aware of the major accessibility issues presented by the use of multimedia objects you will be better prepared to use them wisely in your projects.