Web checklist

Checkpoint AA1.2.5: *WCAG 2.0 AA* Audio Description

Audio description is provided for all prerecorded video content in synchronized media.


Rationale

Blind users cannot see the visual information in a media presentation. This checkpoint requires a synchronized audio description of the visual content to augment the audio portion of a presentation. During existing pauses in the main soundtrack, the user hears an audio description of actions, characters, scene changes, and on-screen text that are important to understand or enjoy the presentation.

A separate audio description is not necessary if the presentation describes all the important information.

This checkpoint overlaps with Checkpoint 1.2b: Audio and Video (Prerecorded). Compliance requirements for Checkpoint 1.2b allow either an audio description or a text alternative that describes the visual content. Checkpoint AA1.2.5 requires an audio description.

Required development and unit test techniques


Compliance with this checkpoint requires one of the following techniques to be met. These techniques are defined in WCAG 2.0 Level AA Success Criterion 1.2.5 (link resides outside of ibm.com).

  1. User selectable audio track: Provide a second, user-selectable audio track that includes audio descriptions.
  2. Movie with audio descriptions: Provide a version of a movie with audio descriptions.
  3. Extended audio descriptions: Provide a version of a movie with extended audio descriptions.

Note: The examples presented in the techniques are not exhaustive. The examples are meant to illustrate the spirit of this checkpoint.

General examples

  1. User selectable audio track: Provide a second, user-selectable audio track that includes audio descriptions.

    To comply with technique 1, you must implement the following example.

    General example 1

    A movie in which the audio description is turned on automatically (link resides outside of ibm.com) to enable people who are blind to listen to the content. People who are visually impaired have the option of turning off the audio descriptions.

    Alternatively, you can create a movie in which the user has the option to turn on the audio description. (link resides outside of ibm.com)

    For additional information, refer to the WCAG 2.0 examples for providing a user-selectable audio track that includes audio descriptions. (link resides outside of ibm.com)

    Required unit tests for general development technique 1

    Perform the following unit tests.

  2. Movie with audio descriptions: Provide a version of a movie with audio descriptions.

    To comply with technique 2, you must implement the following example.

    General example 2

    A movie has an audio description of the actions of the people in the movie as well as any scenery or props that add meaning to the video. This description is added during natural breaks in the dialog of the movie.

    For additional information, refer to the WCAG 2.0 examples for providing a version of a movie with audio descriptions (link resides outside of ibm.com).

    Required unit tests for general development technique 2

    Perform the following unit tests.

  3. Extended audio descriptions: Provide a version of the movie with extended audio descriptions.

    Note: Extended audio descriptions apply to cases in which the user would be lost without an additional audio description and a pause duration in the dialogue or narration is too short to insert the description. In this example, you must edit a video to add a brief pause and insert an audio description into the pause.

    To comply with technique 3, you must implement the following example.

    General example 3

    For additional information, refer to the WCAG 2.0 examples for providing a movie with extended audio descriptions (link resides outside of ibm.com).

    Required unit tests for general development technique 3

    Perform the following unit tests.

    If the alternate versions are on a separate page, ensure there are links available so the user can find the other versions.


Recommended development techniques

Although you are not required to implement the recommended techniques in order to comply with this checkpoint, you should review these techniques because they can improve the accessibility and usability of the application. Refer to WCAG 2.0 Additional Techniques (Advisory) for Success Criterion 1.2.5 (link resides outside of ibm.com) for a list of techniques and examples.


©2013 IBM Corporation

Last updated January 1, 2013.

W3C Recommendation 11 December 2008: http://www.w3.org/TR/WCAG20/ (link resides outside of ibm.com)
Copyright 1994-2009 W3C (Massachusetts Institute of Technology, European Research Consortium for Informatics and Mathematics, Keio University), All Rights Reserved.