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Proposed Audio element content has text alternative

Description

This rule checks that audio elements have a text alternative available.

Applicability

This rule applies to any non-streaming audio element for which at least one of the following is true:

Expectation

For each test target, the outcome of at least one of the following rules is passed:

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

Accessibility Requirements Mapping

Input Rules

Outcomes of the following rules are required as input for this rule.

Test Cases

Passed

Passed Example 1

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This audio element has a play button, and there is a transcript of the audio.

<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 a play button, and 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>

Passed Example 3

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This audio element autoplays, and there is a transcript of the audio.

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

Failed

Failed Example 1

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This audio element has a play button but has an incorrect transcript.

<html lang="en">
	<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>
	<p>
		The above audio contains the following speech: We are going to the North Pole in this decade with puppies,
		not because they are easy, but because they are cute, 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 2

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This audio element autoplays but the text transcript 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" autoplay controls></audio>
</html>

Inapplicable

Inapplicable Example 1

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This audio element does not autoplay or have a play button.

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

Inapplicable Example 2

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This audio element is labeled as an alternative by text on the same page, 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 3

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This a element links to an audio file, but there is no audio element on this 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>
		<a href="/test-assets/moon-audio/moon-speech.mp3">Download the speech as MP3</a>
	</p>
</html>

Glossary

Attribute value

The attribute value of a content attribute set on an HTML element is the value that the attribute gets after being parsed and computed according to specifications. It may differ from the value that is actually written in the HTML code due to trimming whitespace or non-digits characters, default values, or case-insensitivity.

Some notable case of attribute value, among others:

This list is not exhaustive, and only serves as an illustration for some of the most common cases.

The attribute value of an IDL attribute is the value returned on getting it. Note that when an IDL attribute reflects a content attribute, they have the same attribute value.

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.

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.

Implementation Consistency Complete Report
Axe-core Consistent Yes View Report
QualWeb Consistent Yes View Report

Changelog

This is the first version of this ACT rule.

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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/.