Provide accessible alternatives to significant audio and video.
Rationale
Audio content is not accessible to users who are deaf or hard-of-hearing. Video content is not accessible to users who are blind. If the audio and video information are important, they need to be provided in an alternative format which is accessible. Alternatives for audio and video content are also needed by those who have hardware or environmental limitations. For example, the captions on a video can be selected when the audio would be distracting to others in the area.
Section 508 requires that equivalent alternatives for any multimedia presentation be synchronized with the presentation. If the product is to be used by or sold to the U.S. government, for example technical software, the equivalent alternative (such as captions and audio descriptions of the video) must be synchronized with the presentation.
Development techniques
This section describes techniques and examples that support Checkpoint 3.2 from the IBM Java Accessibility Checklist.
One or more of the following techniques are the minimum required for audio:
- Provide a text transcript for the audio. A transcript is a word-for-word textual version of the audio. The user should be given the choice of reading the transcript or listening to the audio, or both. If the product is to be used by or sold to the U.S. government, the transcript must be synchronized with the presentation.
- Provide a text description for the audio. A description is longer and more significant than a transcript. The description can be both subjective and artistic, depending on the intentions of the author. If the product is to be used by or sold to the U.S. government, the description must be synchronized with the presentation.
- Provide a caption or pop-up text window for short audio information. If the product is to be used by or sold to the U.S. government, it must be synchronized with the presentation. Captioning is the rendering of speech and other audible information in to written language of the audio. Captions are usually closed which means the captions are encoded or invisible and must be decoded or made visible. Some captions are open and can't be turned off.
One or more of the following techniques are the minimum required for video:
- Provide a transcript for the video. A transcript is a word-for-word textual or audio version of the video. If the product is to be used by or sold to the U.S. government, the transcript of the audio must be synchronized with the presentation.
- Provide a description for the video. A description of a video track is different from a transcript. The description summarizes any visual information, including action, settings, and characters that are necessary to understand the video. The description of the video should be made available in text and audio form. It can be both subjective and artistic, depending on the intentions of the author. If the product is to be used by or sold to the U.S. government, the description must be synchronized with the presentation.
Using Media Access Generator (MAGpie) (link resides outside of ibm.com) from WGBH, authors can add captions to three multimedia formats: Apple's QuickTime, the World Wide Web Consortium's Synchronized Multimedia Integration Language (SMIL) and Microsoft's Synchronized Accessible Media Interchange (SAMI) format. MAGpie can also integrate audio descriptions into SMIL presentations. For additional information about media formats, tools and players that enable captions and video descriptions, see the WGBH National Center for Accessible Media. (link resides outside of ibm.com)
RealPlayer 7 Basic allows the user to turn on captioning. For more information about RealPlayer 7 Basic, visit: http://www.real.com/ (link resides outside of ibm.com).
The standard Java2 runtime environment does not provide:
- Accessible players for text captioning of the voice track in video content.
- Accessible players for descriptive graphics for audio.
- Accessible players for descriptive text for video.
Examples:
The following example illustrates a transcript of speech and other sounds that enable the deaf and hard of hearing user to understand the content more clearly:
[phone rings]
Man: Are you going to answer the phone?
[phone rings]
[phone rings]
[phone rings]
Woman: No, I'm screening my calls.
[answering machine picks up in the background]
The following is an example of a description file for a sample movie:
[A computer showing text highlighted in a
browser window as the text is read aloud
by a synthesizer]
Reporter: A screen reader tool brings the
voice of the Internet to blind and
visually impaired users.
[A man sitting at the computer listens to
the synthesized voice. Text is highlighted
as it is spoken.]
Computer: [synthesized voice of Screen Reader] ...
A screen reader tool brings the voice of the Internet
to blind and visually impaired users.
[video clip ends.]
Testing techniques
Test the software to ensure that it complies with accessibility requirements.
Tools
You will need to install the following tools to test this checkpoint:
- A screen reader that supports Java to test accessible alternatives for video. A screen reader is not needed if you are only testing accessible alternatives for audio presentations.
Windows techniques
| Action | Result | |
|---|---|---|
| 1 | Verify information in the video is also available with a text
or audio description of the video.
|
Pass:
Fail:
|
| 2 | Verify audio information is also available with a text transcript or captions.
|
Pass:
Fail:
|
©2001, 2008 IBM Corporation
Last updated February 15, 2008.
