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Technique 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 1.2.1: Audio-only and Video-only (Prerecorded) (Sufficient).


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.

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



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

  • Check #1 is true.

Test Rules

The following are Test Rules related to this Technique. It is not necessary to use these particular Test Rules to check for conformance with WCAG, but they are defined and approved test methods. For information on using Test Rules, see Understanding Test Rules for WCAG Success Criteria.

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