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Success Criterion:

Description

Captions are available for audio information in non-streaming video elements.

Accessibility Requirements

This conformance rule relates to:

Test Procedure

Applicability

The rule applies to every non-streaming video element thst is visible where the video contains audio.

Expectation

For each test target, audio information that is not conveyed visually in the video, is available through captions.

Note: Captions can be either embedded in the video file itself or can be made available trough a separate track.

Assumptions

This rule assumes that the video element is used to play a video (for example, not only used to display an image), and that there is a mechanism to start the video.

Accessibility support

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

Background

Test Cases

Passed

Passed example 1

A video element that has captions for all the audio backed into it.

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

Passed example 2

A video element with an associated track element that contain captions for all the audio.

Code Snippet:
 <video src="../test-assets/perspective-video/perspective-video.mp4" controls>
  <track src="/test-assets/perspective-video/perspective-caption.vtt" kind="captions">
</video>
 
Example Output: Open in a new tab/ window

Failed

Failed example 1

A video element with any form of captions.

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

Failed example 2

A video element with an associated track element that contain incorrect captions.

Code Snippet:
 <video src="../test-assets/perspective-video/perspective-keyboard-compatibility-video.mp4" controls>
  <track src="/test-assets/perspective-video/perspective-incorrect-caption.vtt" kind="captions">
</video>
 
Example Output: Open in a new tab/ window

Failed example 3

A video element with a text on the same page that described the audio in the video.

Code Snippet:
 <p>The video below shows a man working on a keyboard. A voiceover is heard 
  saying the following text: Web accessibility perspectives. Keyboard 
  compatibility. 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.</p>
<video src="../test-assets/perspective-video/perspective-keyboard-compatibility-video.mp4" controls>
</video>
 
Example Output: Open in a new tab/ window

Failed example 4

A video element with an explicitly associated text on the same page that described the audio in the video.

Code Snippet:
 <p id="text">The video below shows a man working on a keyboard. A voiceover is heard 
  saying the following text: Web accessibility perspectives. Keyboard 
  compatibility. 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.</p>
<video src="../test-assets/perspective-video/perspective-keyboard-compatibility-video.mp4" controls ariadescribedby="text">
</video>
 
Example Output: Open in a new tab/ window

Inapplicable

Inapplicable example 1

A video element without audio.

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

Inapplicable example 2

A video element without that is not visible on the page.

Code Snippet:
 <video src="../test-assets/perspective-video/perspective-video.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.

Test Aspects

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

  • CSS Styling

  • Audio output

  • Visual output

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