31. Complete Narration or Audio Description

When multimedia (e.g. video, narrated animation) includes important visual and auditory information, provide spoken description of any significant visual elements that would be missed when listening to the audio alone.
Notes:

• If you have an interactive with both important sound and motion, but they are presented separately, with transitions triggered by the user, you can use the simpler accommodations described in Pearson Guideline 29 (alternative text) and Pearson Guideline 36 (captions).
• In cases where the spoken description needed is not helpful for all audiences, the additional description should go into a separate audio track or second version of the video.

Rationale

People with vision impairment can often follow most of the content of multimedia by listening to the audio. However, when key events and visuals are not apparent through the default sound track, additional information is needed. By adding spoken descriptions that play during the multimedia, we can provide that information at the right moments during the video, making it possible for those with visual impairments to follow the default audio.

Note: These spoken descriptions of the visual content of multimedia are called audio descriptions, where “audio” refers to the mode of delivery.

General Techniques

• If the visuals are insignificant, for example, a speaker who does not provide any type of demonstration, there is no need to provide audio description of the visuals.
• If the sounds are insignificant, for example, background music, the media can be treated as a silent animation. See Pearson Guideline 29.

• Audio description can be:

  • included in a separate audio description track that can be activated or deactivated
  • provided in a separate copy of the multimedia
    OR
  • worked into the default sound track for all users
• When possible, provide spoken description of visuals during pauses in the soundtrack. If pauses in the soundtrack are too short or too infrequent, pause the media to insert sufficient description of the visual information.
• It is only necessary to describe those visual elements needed to understand the multimedia through audio alone.
• When providing audio description it can be helpful to have the description label background sounds. For example, although understanding a zoologist’s philosophy may not require knowing what animal is behind her, if the animal is growling, people are going to wonder. Try to include the information in a natural way, with other important information, as in, “Professor Smith of the Smith Zoo speaks to a small crowd at the zoo’s lion exhibit.”
• For more information on audio description, visit the Audio Description Project in a new window.

Testing

Testing technique	Description
Review	Check for any options to turn on “Audio Description.” This is often provided using links that say simply “AD”. If audio description exists, activate it. Listen to the video with your screen off. Note whether anything is confusing. Watch the video. Note whether any important information is available only through the visuals.
Analysis	Report as errors any cases where listening to the audio alone is confusing. For example, you may not know who was speaking. Also, report as errors any cases where important information was available only in the visuals. For example, the liquid in a chemistry experiment may have turned blue without this detail being mentioned by the narrator.

Related Guidelines

508 § 1194.22 Web (b)

Equivalent alternatives for any multimedia presentation shall be synchronized with the presentation.

WCAG 2.0 Level A - 1.2.3 Audio Description or Media Alternative:

An alternative for time-based media or audio description of the prerecorded video content is provided for synchronized media, except when the media is a media alternative for text and is clearly labeled as such. (Level A)

WCAG 2.0 Level AA - 1.2.5 Audio Description:

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

WCAG 2.0 Level AAA - 1.2.7 Audio Description (Extended):

Where pauses in foreground audio are insufficient to allow audio descriptions to convey the sense of the video, extended audio description is provided for all prerecorded video content in synchronized media. (Level AAA)