Techniques for WCAG 2.0

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G166: Providing audio that describes the important video content and describing it as such


All technologies that can contain video content

This technique relates to:


Video-only content is inaccessible to people who are blind and to some who have low vision. Therefore, it is important for them to have an audio alternative. One way of doing this is to provide an audio track describing the information in the video. The audio should be a common audio format used on the internet, such as MP3.


Example 1

A Web page has a link to a video-only presentation of a spaceship landing on Mars. The link to the video is a picture of a spaceship. Near the video is a link to an audio file of a person describing the video. This would look something like the following code example in HTML.

Example Code:

              <a href="../video/marslanding.mp4"><img src="../images/spaceship.jpg" 
                alt="Mars landing, video-only" width="193" height="255"/></a>
                <br />
                <a href="Mars_landing_audio.mp3">Audio description of "Mars Landing"</a>



For a Web page that contains video-only content:

  1. Check that there is link to an audio alternative which describes the contents of the video immediately before or after the video-only content.

Expected Results

If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.

Techniques are Informative

Techniques are informative—that means they are not required. The basis for determining conformance to WCAG 2.0 is the success criteria from the WCAG 2.0 standard—not the techniques. For important information about techniques, please see the Understanding Techniques for WCAG Success Criteria section of Understanding WCAG 2.0.