Checkpoint 1.2.5 Audio Description (Prerecorded)

Audio description is provided for all prerecorded video content in synchronized media. (Level AA)

Rationale

Blind users cannot see the visual information in a media presentation. This checkpoint requires an audio description (also sometimes called video descriptions or descriptive narration) of the visual content to augment the audio portion of a presentation. This audio description is synchronized with the content; 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. Secondary or alternate audio tracks are commonly used for this purpose.

Note: This checkpoint overlaps with Checkpoint 1.2.3: Audio Description or Media Alternative (Prerecorded). Compliance requirements for Checkpoint 1.2.3 allow either an audio description or a text alternative that describes the visual content. However, the current checkpoint, 1.2.5, requires an audio description to comply at the WCAG AA level. 

Exception: If all important visual information is already announced in the audio track, or there is no important information in the video track (such as a “talking head”, where a person is talking in front of an unchanging background), no audio description is necessary, and only the Media Alternative requirement of checkpoint 1.2.3 needs to be met.

Refer to Understanding SC 1.2.5 for more information (external link to WCAG).

Development Techniques

Review the General techniques as well as other tabs applicable to your technology.  Prioritize the use of technology-specific techniques, and implement the General techniques as needed. You are always required to find, understand and implement accessible code techniques to meet the checkpoint. The documented techniques and supplements are not exhaustive; they illustrate acceptable ways to achieve the spirit of the checkpoint. If numbered, techniques are in order of preference, with recommended techniques listed first. Where used, IBM information that complements the WCAG techniques is indicated as supplemental.

General techniques

Any item in this section represents a technique or combination or techniques that is deemed sufficient.

General Supplements

G173 Supplement

When media players are unable to offer controls for audio descriptions, another means of supporting this requirement is to provide a second version of the video which has incorporated the audio descriptions directly into the soundtrack. This second version should be offered at the same level of prominence, typically through a clearly labelled link

Web (HTML, ARIA, CSS) techniques

Instructions: Any item in this section represents a technique or combination of techniques deemed sufficient to address particular situations.

Mobile (iOS) techniques

There are no specific Mobile Native iOS technniques for this checkpoint. However, in addition to the General and Web techniques, the techniques in this section provide additional information and context for hybrid applications.

Hybrid techniques

Meeting G173: Providing a version of a movie with audio descriptions using the following:

Hybrid supplements

H96: Using the track element to provide audio descriptions

Apple recommends using the HTML5 <audio>, <video>, and <track> elements for audio and video content on mobile Safari. These elements support audio and video playback natively in the browser  using the browser's  built-in controls.  Developers can also create their own customized media controllers for rich interactivity using web-standard CSS and JavaScript.  Developers should references Apple's "About HTML5 Audio and Video", "iOS-Specific Considerations", and "Use audio descriptions to hear narration describing a video clip, show, or movie" for proper implementation.

Eclipse techniques

There are no specific Eclipse techniques for this checkpoint. Refer to the General techniques section.

Windows-based (MSAA+IA2) techniques

There are no specific Windows-based (MSAA+IA2) techniques for this checkpoint. Refer to the General techniques section.


Most links in this checklist reside outside ibm.com at the Web Content Accessibility Guidelines (WCAG) 2.0. W3C Recommendation 11 December 2008: http://www.w3.org/TR/WCAG20/

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