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Description

This rule checks non-streaming silent video is a media alternative for text on the page.

Test Procedure

Applicability

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

Expectation 1

All the information contained in each target element is available as text (directly or via text alternatives) that is visible and included in the accessibility tree.

Expectation 2

Each target element is labelled as an video alternative for text on the page.

Expectation 3

The label (from expectation 2) is visible and included in the accessibility tree

Note: The term label does not refer to the label element.

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

There are no major accessibility support issues known for this rule.

Background

Test cases

Passed

Passed 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 src="../test-assets/perspective-video/perspective-video-with-captions-silent.mp4" controls>
</video>
 
Example Output: Open in a new tab/ window

Failed

Failed example 1

A video element that describes some of the text on the same page. The video contains more information than the text does.

Code Snippet:
 
<p>Not being able to use your computer because your mouse 
  doesn't work, is frustrating. 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 src="../test-assets/perspective-video/perspective-video-with-captions-silent.mp4" controls>
</video>
 
Example Output: Open in a new tab/ window

Failed example 2

A video element that describes some of the text on the same page. The text is not visible on the page.

Code Snippet:
 <p style="display: none;">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 src="../test-assets/perspective-video/perspective-video-with-captions-silent.mp4" controls>
</video>
 
Example Output: Open in a new tab/ window

Failed example 3

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 src="../test-assets/perspective-video/perspective-video-with-captions-silent.mp4" controls>
</video>
 
Example Output: Open in a new tab/ window

Failed example 4

A video element that describes some of the text on the same page. The text on the page labels the video as an alternative but the label is not visible on the page.

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>
  <p style="display: none;">See the video below to watch the same information again in video form.</p>
<video src="../test-assets/perspective-video/perspective-video-with-captions-silent.mp4" controls>
</video>
 
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 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 element that describes some of the text on the same page. The text on the page labels the video as an alternative but the video is not visible on the page.

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 src="../test-assets/perspective-video/perspective-video-with-captions-silent.mp4" controls style="display: none;">
</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.

Included in the accessibility tree

Elements included in the accessibility tree of platform specific accessibility APIs. Elements in the accessibility tree are exposed to assistive technologies, allowing users to interact with the elements in a way that meet the requirements of the individual user.

The general rules for when elements are included in the accessibility tree are defined in the core accessibility API mappings. For native markup languages, such as HTML and SVG, additional rules for when elements are [included in the accessibility tree][] can be found in the HTML accessibility API mappings and the SVG accessibility API mappings.

Note: Users of assistive technologies might still be able to interact with elements that are not included in the accessibility tree. An example of this is a focusable element with an aria-hidden attribute with a value of true. Such an element could still be interacted with using sequential keyboard navigation regardless of the assistive technologies used, even though the element would not be included in the accessibility tree.

Test Aspects

Test aspects are defined as part of the ACT Rules format 1.0.
  • DOM Tree

  • CSS Styling

  • Audio output

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