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Proposed Audio element content is media alternative for text

Description

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

Applicability

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

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 by content that is visible and included in the accessibility tree.

Assumptions

There are no assumptions.

Accessibility Support

There are no accessibility support issues known.

Background

Bibliography

Accessibility Requirements Mapping

This rule is not required for conformance.

Input Aspects

The following aspects are required in using this rule.

Test Cases

Passed

Passed Example 1

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This audio element 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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This audio element 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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This audio element 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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This audio element 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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This audio element 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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This audio element 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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This audio element 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

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:

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.

Non-streaming media element

A non-streaming media element is an HTML Media Element for which the duration property is not 0.

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:

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.

Play button

A play button is an instrument that when activated plays a media resource.

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:

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.

Rule Versions

This is the first version of this ACT rule.

Implementations

There are currently no known implementations for this rule. If you would like to contribute an implementation, please read the ACT Implementations page for details.

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This is an unpublished draft preview that might include content that is not yet approved. The published website is at w3.org/WAI/.