audio element content is media alternative for text


Description

This rule checks audio is a media alternative for text on the page.

Applicability

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

Note: A play button is an interactive element that when activated, plays the audio.

Expectation 1

The auditory information of each test target is available as text (directly or via text alternatives) that is visible and included in the accessibility tree.

Expectation 2

Each target element is labeled as an audio 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 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

Test Cases

Passed

Passed Example 1

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An audio element that describes some of the text on the same page. The text on the page labels the audio as an alternative.

<html lang="en">
	<p>
		A part of a speech by John F. Kennedy: 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>
	<p>
		You can also listen to the audio file below to hear the above part of the speech.
	</p>
	<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
</html>

Failed

Failed Example 1

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

<html lang="en">
	<p>
		A part of a speech by John F. Kennedy: 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.
	</p>
	<p>
		You can also listen to the audio file below to hear the above part of the speech.
	</p>
	<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
</html>

Failed Example 2

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An audio element that describes some of the text on the same page. The text is not visible on the page.

<html lang="en">
	<p style="display: none;">
		A part of a speech by John F. Kennedy: 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>
	<p>
		You can also listen to the audio file below to hear the above part of the speech.
	</p>
	<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
</html>

Failed Example 3

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

<html lang="en">
	<p>
		A part of a speech by John F. Kennedy: 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>
	<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
</html>

Failed Example 4

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

<html lang="en">
	<p>
		A part of a speech by John F. Kennedy: 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>
	<p style="display: none;">
		You can also listen to the audio file below to hear the above part of the speech.
	</p>
	<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
</html>

Inapplicable

Inapplicable Example 1

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An audio element that describes some of the text on the same page. The text on the page labels the audio as an alternative but the controls are not visible on the page.

<html lang="en">
	<p>
		A part of a speech by John F. Kennedy: 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>
	<p>
		You can also listen to the audio file below to hear the above part of the speech.
	</p>
	<audio src="/test-assets/moon-audio/moon-speech.mp3" controls style="display: none;"></audio>
</html>

Inapplicable Example 2

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An audio element that describes some of the text on the same page. The text on the page labels the audio as an alternative but there are no controls.

<html lang="en">
	<p>
		A part of a speech by John F. Kennedy: 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>
	<p>
		You can also listen to the audio file below to hear the above part of the speech.
	</p>

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

Glossary

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 (working draft) and the SVG accessibility API mappings (working draft).

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

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 using sequential keyboard navigation regardless of the assistive technologies used, even though the element would not be included in the accessibility tree.

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.

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.

ToolConsistencyCompleteReport
QualWebconsistentYesView Report

Acknowledgments

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