Last updated:

Created by:

Success Criterion:

Atomic Rules:

Description

This rule checks if video elements without audio have an alternative available

Accessibility Requirements

This conformance rule relates to:

Test Procedure

Applicability

The rule applies to any non-streaming video element visible, where the video doesn’t contain audio.

Expectation

For each test target, the outcome of at least one of the following rules is passed:

Assumptions

This rule assumes that a mechanism is available to start the video and that the video element is not simply used to display the poster.

Accessibility support

See Video only element description track: accessibility support.

Background

Test Cases

Passed

Pass example 1

A video element without audio. The text on the page labels the video as an alternative.

Code Snippet:
 <p>Not being able to use your computer because your mouse 
  doesn't work, is frustrating. Many people use only the keyboard to navigate 
  websites. Either through preference or circumstance. This is solved by keyboard compatibility. 
  Keyboard compatibility is described in WCAG.
  See the video below to watch the same information again in video form.</p>
<video data-rule-target src="../test-assets/perspective-video/perspective-video-with-captions-silent.mp4" controls>
</video>
 
Example Output: Open in a new tab/ window

Pass example 2

A video only element with a track element that contains descriptions.

Code Snippet:
 <video controls>
  <source src="../test-assets/rabbit-video/silent.mp4" type="video/mp4" />
  <source src="../test-assets/rabbit-video/silent.webm" type="video/webm" />
  <track kind="descriptions" src="rabbit-video-descriptions.vtt" />
</video>
 
Example Output: Open in a new tab/ window

Pass example 3

A silent video element with a text transcript on the same page.

Code Snippet:
 <video controls data-rule-target>
  <source src="../test-assets/rabbit-video/silent.mp4" type="video/mp4"></source>
  <source src="../test-assets/rabbit-video/silent.webm" type="video/webm"></source>
</video>
<p>The above video shows a giant fat rabbit climbing out of a hole in the ground. 
He stretches, yaws, and then starts walking. 
Then he stops to scratch his bottom.</p>
 
Example Output: Open in a new tab/ window

Pass example 4

A video element without audio has a separate audio track that describes the visual information.

Code Snippet:
 <video controls>
  <source src="../test-assets/rabbit-video/silent.mp4" type="video/mp4" />
  <source src="../test-assets/rabbit-video/silent.webm" type="video/webm" />
</video>

<audio controls>
  <source src="../test-assets/rabbit-video/audio-description.mp3" type="audio/mpeg">
</audio>
 
Example Output: Open in a new tab/ window

Failed

Fail example 1

A video element that describes some of the text on the same page. The text on the page does not label the video as an alternative.

Code Snippet:
 <p>Not being able to use your computer because your mouse 
  doesn't work, is frustrating. Many people use only the keyboard to navigate 
  websites. Either through preference or circumstance. This is solved by keyboard compatibility. 
  Keyboard compatibility is described in WCAG.</p>
<video data-rule-target src="../test-assets/perspective-video/perspective-video-with-captions-silent.mp4" controls>
</video>
 
Example Output: Open in a new tab/ window

Fail example 2

A video only element with a track element that contains incorrect descriptions.

Code Snippet:
 <video controls>
  <source src="../test-assets/rabbit-video/silent.mp4" type="video/mp4" />
  <source src="../test-assets/rabbit-video/silent.webm" type="video/webm" />
  <track kind="descriptions" src="rabbit-video-incorrect-descriptions.vtt" />
</video>
 
Example Output: Open in a new tab/ window

Fail example 3

A silent video element with a link to an incorrect text transcript on a different page.

Code Snippet:
 <video controls data-rule-target>
  <source src="../test-assets/rabbit-video/silent.mp4" type="video/mp4"></source>
  <source src="../test-assets/rabbit-video/silent.webm" type="video/webm"></source>
</video>
<a href="/test-assets/rabbit-video-incorrect-transcript.html">Transcript</p>
 
Example Output: Open in a new tab/ window

Fail example 4

A video element without audio has a separate audio track that incorrectly describes the visual information.

Code Snippet:
 <video controls>
  <source src="../test-assets/rabbit-video/silent.mp4" type="video/mp4" />
  <source src="../test-assets/rabbit-video/silent.webm" type="video/webm" />
</video>

<audio controls>
  <source src="../test-assets/rabbit-video/incorrect-audio-description.mp3" type="audio/mpeg">
</audio>
 
Example Output: Open in a new tab/ window

Inapplicable

Inapplicable example 1

A video element with audio.

Code Snippet:
 <p>Not being able to use your computer because your mouse 
  doesn't work, is frustrating. Many people use only the keyboard to navigate 
  websites. Either through preference or circumstance. This is solved by keyboard compatibility. 
  Keyboard compatibility is described in WCAG.
  See the video below to watch the same information again in video form.</p>
<video data-rule-target src="../test-assets/perspective-video/perspective-keyboard-compatibility-video.mp4" controls>
</video>
 
Example Output: Open in a new tab/ window

Inapplicable example 2

A video only element that is not visible on the page.

Code Snippet:
 <video controls style="display: none;">
  <source src="../test-assets/rabbit-video/silent.mp4" type="video/mp4" />
  <source src="../test-assets/rabbit-video/silent.webm" type="video/webm" />
  <track kind="descriptions" src="rabbit-video-descriptions.vtt" />
</video>
 
Example Output: Open in a new tab/ window

Glossary

Visible

Content perceivable through sight.

Content is considered visible if making it fully transparent would result in a difference in the pixels rendered for any part of the document that is currently within the viewport or can be brought into the viewport via scrolling.

Content is defined in WCAG.

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