ACT-Rules Community

Audio element content has transcript

Description

This rule checks that audio elements have a transcript that includes all auditory information.

Applicability

This rule applies to every non-streaming audio element that is:

Expectation

The auditory information of each test target is available through a text transcript. That text transcript is visible and included in the accessibility tree, either on the page or through a link.

Note: A "text transcript" in the context of this rule is defined in WCAG 2 as an alternative for time based media.

Assumptions

This rule assumes that the language of each test target can be correctly determined (either programmatically or by analyzing the content), and sufficiently understood.

Accessibility Support

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

Background

Bibliography

Test Cases

Passed

Passed Example 1

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This audio element has native player controls and an internal transcript.

<html lang="en">
	<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
	<p>
		The above audio contains the following speech: We choose to go to the moon in this decade and do the other things,
		not because they are easy, but because they are hard, because that goal will serve to organize and measure the best
		of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to
		postpone, and one which we intend to win, and the others, too.
	</p>
</html>

Passed Example 2

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This audio element has native player controls and an external transcript.

<html lang="en">
	<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
	<a href="/test-assets/moon-audio/moon-speech-transcript.txt">Transcript</a>
</html>

Passed Example 3

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This audio element has an autoplay attribute and an external transcript.

<html lang="en">
	<audio src="/test-assets/moon-audio/moon-speech.mp3" autoplay></audio>
	<a href="/test-assets/moon-audio/moon-speech-transcript.txt">Transcript</a>
</html>

Failed

Failed Example 1

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This audio element has native player controls and no transcript.

<html lang="en">
	<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
</html>

Failed Example 2

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This audio element has native player controls and an incorrect internal transcript.

<html lang="en">
	<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
	<p>
		The above audio contains the following speech: We choose to go to the cheese in this decade and do the other things,
		not because they are easy, but because they are hard, because that goal will serve to organize and measure the best
		of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to
		postpone, and one which we intend to win, and the others, too.
	</p>
</html>

Failed Example 3

Open in a new tab

This audio element has native player controls and an incorrect external transcript.

<html lang="en">
	<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
	<a href="/test-assets/moon-audio/moon-speech-incorrect-transcript.txt">Transcript</a>
</html>

Failed Example 4

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This audio element has an autoplay attribute and an incorrect external transcript.

<html lang="en">
	<audio src="/test-assets/moon-audio/moon-speech.mp3" autoplay></audio>
	<a href="/test-assets/moon-audio/moon-speech-incorrect-transcript.txt">Transcript</a>
</html>

Failed Example 5

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This audio element has native player controls and a non-visible internal transcript.

<html lang="en">
	<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
	<p style="text-indent: -9999px;">
		The above audio contains the following speech: We choose to go to the moon in this decade and do the other things,
		not because they are easy, but because they are hard, because that goal will serve to organize and measure the best
		of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to
		postpone, and one which we intend to win, and the others, too.
	</p>
</html>

Failed Example 6

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This audio element has native player controls and an internal transcript that is not exposed to the accessibility tree.

<html lang="en">
	<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
	<p aria-hidden="true">
		The above audio contains the following speech: We choose to go to the moon in this decade and do the other things,
		not because they are easy, but because they are hard, because that goal will serve to organize and measure the best
		of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to
		postpone, and one which we intend to win, and the others, too.
	</p>
</html>

Inapplicable

Inapplicable Example 1

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This audio element has no native player controls.

<html lang="en">
	<audio src="/test-assets/moon-audio/moon-speech.mp3"></audio>
</html>

Inapplicable Example 2

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This audio element has hidden native player controls.

<html lang="en">
	<audio src="/test-assets/moon-audio/moon-speech.mp3" controls style="display: none;"></audio>
</html>

Glossary

Focusable

An element is focusable if one or both of the following are true:

Exception: Elements that lose focus during a period of up to 1 second after gaining focus, without the user interacting with the page the element is on, are not considered focusable.

Notes:

  • The 1 second time span is an arbitrary limit which is not included in WCAG. Given that scripts can manage the focus state of elements, testing the focusability of an element consistently would be impractical without a time limit.
  • The tabindex value of an element is the value of the tabindex attribute parsed using the rules for parsing integers. For the tabindex value to be different from null, it needs to be parsed without errors.

Included in the accessibility tree

Elements included in the accessibility tree of platform specific accessibility APIs are exposed to assistive technologies. This allows users of assistive technology to access the elements in a way that meets 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 (working draft) and the SVG accessibility API mappings (working draft).

For more details, see examples of included in the accessibility tree.

Programmatically hidden elements are removed from the accessibility tree. However, some browsers will leave focusable elements with an aria-hidden attribute set to true in the accessibility tree. Because they are hidden, these elements are considered not included in the accessibility tree. This may cause confusion for users of assistive technologies because they may still be able to interact with these focusable elements using sequential keyboard navigation, even though the element should not be included in the accessibility tree.

Instrument to achieve an objective

An HTML element that when activated allows an end-user to achieve an objective.

Note: Any rule that uses this definition must provide an unambiguous description of the objective the instrument is used to achieve.

Background About Instrument for Instrument to achieve an objective

This definition is a more restrictive version of WCAG's definition of mechanism, notably restricting it to the current document. WCAG has a note that "The mechanism needs to meet all success criteria for the conformance level claimed." This includes all the level A criteria such as Success Criterion 2.1.1 Keyboard (the mechanism must be keyboard accessible) or Success Criterion 4.1.2 Name, Role, Value (the mechanism must be exposed to assistive technologies and have an accessible name). This definition, and the rules using it, leaves these extra requirements out. This avoids reporting the same component twice for the same reason (e.g., missing an accessible name) under two different rules and Success Criteria, and helps pinpoint the error related to each Success Criterion. Instruments should nonetheless be fully accessible at the correct conformance level (depending on the rule using them).

Outcome

An outcome is a conclusion that comes from evaluating an ACT Rule on a test subject or one of its constituent test target. An outcome can be one of the three following types:

  • Inapplicable: No part of the test subject matches the applicability
  • Passed: A test target meets all expectations
  • Failed: A test target does not meet all expectations

Note: A rule has one passed or failed outcome for every test target. When there are no test targets the rule has one inapplicable outcome. This means that each test subject will have one or more outcomes.

Note: Implementations using the EARL10-Schema can express the outcome with the outcome property. In addition to passed, failed and inapplicable, EARL 1.0 also defined an incomplete outcome. While this cannot be the outcome of an ACT Rule when applied in its entirety, it often happens that rules are only partially evaluated. For example, when applicability was automated, but the expectations have to be evaluated manually. Such "interim" results can be expressed with the incomplete outcome.

Programmatically Hidden

An HTML element is programmatically hidden if either it has a computed CSS property visibility whose value is not visible; or at least one of the following is true for any of its inclusive ancestors in the flat tree:

  • has a computed CSS property display of none; or
  • has an aria-hidden attribute set to true

Note: Contrary to the other conditions, the visibility CSS property may be reverted by descendants.

Note: The HTML standard suggests setting the CSS display property to none for elements with the hidden attribute. While not required by HTML, all modern browsers follow this suggestion. Because of this the hidden attribute is not used in this definition. In browsers that use this suggestion, overriding the CSS display property can reveal elements with the hidden attribute.

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.

For more details, see examples of visible.

Useful Links

Implementations

This section is not part of the official rule. It is populated dynamically and not accounted for in the change history or the last modified date. This section will not be included in the rule when it is published on the W3C website.

No Implementations

Implementation reports are not provided for this rule.

Acknowledgments

Authors

Funding

  • WAI-Tools

Assets

  • JFK's "We Choose the Moon" speech excerpt is courtesy of NASA.
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