Understanding WCAG 2.0

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Audio Description or Full Text Alternative :
Understanding SC 1.2.2

1.2.2 Audio Description or Full Text Alternative: Audio description of [begin change] the video information [end change] , or a full text alternative for synchronized media including any interaction, is provided for prerecorded synchronized media. (Level A)

Note: For 1.2.2, 1.2.4, and 1.2.6, if all of the information in the video track is already provided in the audio track, no audio description is necessary.

Intent of this Success Criterion

The intent of this Success Criterion is to provide people who are blind or visually impaired access to the visual information in a synchronized media presentation. This Success Criterion describes two approaches, either of which can be used.

One approach is to provide audio description of the video content. The audio description augments the audio portion of the presentation with the information needed when the video portion is not available. During existing pauses in dialogue, audio description provides information about actions, characters, scene changes, and on-screen text that are important and are not described or spoken in the main sound track.

The second approach involves providing all of the information in the synchronized media (both visual and auditory) in text form. A full text alternative for synchronized media including any interaction provides a running description of all that is going on in the synchronized media content. The full text alternative for synchronized media including any interaction reads something like a screenplay or book. Unlike audio description, the description of the video portion is not constrained to just the pauses in the existing dialogue. Full descriptions are provided of all visual information, including visual context, actions and expressions of actors, and any other visual material. In addition, non-speech sounds (laughter, off-screen voices, etc.) are described, and transcripts of all dialogue are included. The sequence of description and dialogue transcripts are the same as the sequence in the synchronized media itself. As a result, the full text alternative for synchronized media can provide a much more complete representation of the synchronized media content than audio description alone.

If there is any interaction as part of the synchronized media presentation (e.g. "press now to answer the question") then the full text alternative for synchronized media would provide hyperlinks or whatever is needed to provide the same functionality.

Note 1: For 1.2.2, 1.2.4, and 1.2.6, if all of the information in the video track is already provided in the audio track, no audio description is necessary.

Note 2: 1.2.2, 1.2.4, and 1.2.7 overlap somewhat with each other. This is to give the author some choice at the minimum conformance level, and to provide additional requirements at higher levels. At Level A in Success Criterion 1.2.2, authors do have the choice of providing either an audio description or a full text alternative. If they wish to conform at Level AA, under Success Criterion 1.2.4 authors must provide an audio description - a requirement already met if they chose that alternative for 1.2.2, otherwise an additional requirement. At Level AAA under Success Criterion 1.2.7 they must provide an extended text description. This is an additional requirement if both 1.2.2 and 1.2.4 were met by providing an audio description only. If 1.2.2 was met, however, by providing a text description, and the 1.2.4 requirement for an audio description was met, then 1.2.7 does not add new requirements.

Specific Benefits of Success Criterion 1.2.2:

  • This Success Criterion may help some people who have difficulty watching video or other synchronized media content, including people who have difficulty perceiving or understanding moving images.

Examples of Success Criterion 1.2.2

Related Resources

Resources are for information purposes only, no endorsement implied.

Techniques and Failures for Success Criterion 1.2.2 - Audio Description or Full Text Alternative

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this Success Criterion. The techniques listed only satisfy the Success Criterion if all of the WCAG 2.0 conformance requirements have been met.

Sufficient Techniques

  1. G69: Providing a full synchronized media text alternative including any interaction

  2. G78: Providing a sound track that includes audio description as the primary sound track

  3. G78: Providing a sound track that includes audio description AND associating it with the synchronized media content using one of the following techniques:

  4. Providing audio description in its own sound track (future link) AND merging the description track with the original soundtrack of the synchronized media content at runtime using one of the following techniques

    • Using SMIL 1.0 to merge a description track with sound track (future link)

    • Using SMIL 2.0 to merge a description track with sound track (future link)

Additional Techniques (Advisory) for 1.2.2

Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.

  • Providing audio description in multiple languages in SMIL 1.0 (future link)

  • Providing audio description in multiple languages in SMIL 2.0 (future link)

Common Failures for SC 1.2.2

The following are common mistakes that are considered failures of Success Criterion 1.2.2 by the WCAG Working Group.

(No failures currently documented)

Key Terms

audio description

narration added to the soundtrack to describe important visual details that cannot be understood from the main soundtrack alone

Note 1: Audio description of video provides information about actions, characters, scene changes, on-screen text, and other visual content.

Note 2: In standard audio description, narration is added during existing pauses in dialogue. (See also extended audio description.)

Note 3: Also called "video description" and "descriptive narration."

full text alternative for synchronized media including any interaction

document including correctly sequenced text descriptions of all visual settings, actions, speakers, and non-speech sounds, and transcript of all dialogue combined with a means of achieving any outcomes that are achieved using interaction (if any) during the synchronized media

Note: A screenplay used to create the synchronized media content would meet this definition only if it was corrected to accurately represent the final synchronized media after editing.

synchronized media

audio or video synchronized with another format for presenting information and/or with time-based interactive components