Understanding WCAG 2.0

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Media Alternative:
Understanding SC 1.2.8

1.2.8 Media Alternative: [begin delete]A full text alternative for synchronized media including any interaction[end delete][begin add]An alternative for time-based media[end add] is provided for all prerecorded synchronized media and [begin delete]a text alternative that presents equivalent information is provided [end delete]for all prerecorded video-only media. (Level AAA)

Intent of this Success Criterion

The intent of this Success Criterion is to make audio visual material available to individuals whose vision is too poor to reliably read captions and whose hearing is too poor to reliably hear dialogue and audio description. This is done by providing an alternative for time-based media.

This approach involves providing all of the information in the synchronized media (both visual and auditory) in text form. An alternative for time-based media provides a running description of all that is going on in the synchronized media content. The alternative for time-based media reads something like a 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 descriptions and dialogue transcripts is the same as the sequence in the synchronized media itself. As a result, the alternative for time-based 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 alternative for time-based media would provide hyperlinks or whatever is needed to provide parallel functionality.

Individuals whose vision is too poor to reliably read captions and whose hearing is too poor to reliably hear dialogue can access the alternative for time-based media by using a refreshable braille display.

Note 1: For 1.2.3, 1.2.5, and 1.2.7, if all of the information in the video track is already provided in the audio track, no audio description is necessary.

Note 2: 1.2.3, 1.2.5, and 1.2.8 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 1.2.3, 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 1.2.5 authors must provide an audio description - a requirement already met if they chose that alternative for 1.2.3, otherwise an additional requirement. At Level AAA under Success Criterion 1.2.8 they must provide an extended text description. This is an additional requirement if both 1.2.3 and 1.2.5 were met by providing an audio description only. If 1.2.3 was met, however, by providing a text description, and the 1.2.5 requirement for an audio description was met, then 1.2.8 does not add new requirements.

Specific Benefits of Success Criterion 1.2.8:

  • People who cannot see well or at all and who also cannot hear well or at all can get access to information in audio-visual presentations.

Examples of Success Criterion 1.2.8

Related Resources

Resources are for information purposes only, no endorsement implied.

(none currently documented)

Techniques and Failures for Success Criterion 1.2.8 - Media 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

Instructions: Select the situation below that matches your content. Each situation includes techniques or combinations of techniques that are known and documented to be sufficient for that situation.

Situation A: If the content is prerecorded synchronized media:

  1. G69: Providing an alternative for time based media using one of the following techniques

Situation B: If the content is prerecorded video-only:

  1. G159: Providing an alternative for time-based media of the video content

Additional Techniques (Advisory) for 1.2.8

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.

Common Failures for SC 1.2.8

The following are common mistakes that are considered failures of Success Criterion 1.2.8 by the WCAG Working Group.

Key Terms

[begin add]alternative for time-based media[end add][begin delete]full text alternative for synchronized media including any interaction[end delete]

document including correctly sequenced text descriptions of [begin delete]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[end delete][begin add]time-based visual and auditory information and providing a means for achieving the outcomes of any time-based interaction [end add]

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.


information that is not live

synchronized media

audio or video synchronized with another format for presenting information and/or with time-based interactive components, unless the media is a media alternative for text that is clearly labeled as such


a time-based presentation that contains only video (no audio and no interaction)