Proposed Test Rule: audio element content has text alternative
Applicability
This rule applies to any non-streaming audio
element that is:
- playing; or,
- has a “play button” that is visible and included in the accessibility tree.
Note: A play button is an interactive element that when activated, plays the audio.
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
- Understanding SC 1.2.1:Audio-only and Video-only (Prerecorded)
- G158: Providing an alternative for time-based media for audio-only content
Accessibility Requirements Mapping
1.2.1 Audio-only and Video-only (Prerecorded) (Level A)
- Learn more about 1.2.1 Audio-only and Video-only (Prerecorded)
- Required for conformance to WCAG 2.0 and later on level A and higher.
- Outcome mapping:
- Any
failed
outcomes: success criterion is not satisfied - All
passed
outcomes: success criterion needs further testing - An
inapplicable
outcome: success criterion needs further testing
- Any
G158: Providing an alternative for time-based media for audio-only content
- Learn more about technique G158
- Not required for conformance to any W3C accessibility recommendation.
- Outcome mapping:
- Any
failed
outcomes: technique is not satisfied - All
passed
outcomes: technique needs further testing - An
inapplicable
outcome: technique needs further testing
- Any
Input Rules
Outcomes of the following rules are required as input for this rule.
Test Cases
Passed
Passed Example 1
Audio with controls and 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
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
Audio with controls and 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 2
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>
Inapplicable
Inapplicable Example 1
Audio without controls.
<html lang="en">
<audio src="/test-assets/moon-audio/moon-speech.mp3"></audio>
</html>
Inapplicable Example 2
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 3
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 speach as MP3</a>
</p>
</html>
Glossary
Focusable
An element is focusable if one or both of the following are true:
- the element is part of sequential focus navigation; or
- the element has a tabindex value that is not null.
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.
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:
- 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
ofnone
; or - has an
aria-hidden
attribute set totrue
Note: Contrarily to the other conditions, the visibility
CSS property may be reverted by descendants.
Note: The HTML standard suggests rendering elements with the hidden
attribute with a CSS rule that applies the value none
to the CSS property display
of the element. Although the suggestion is not normative, known user agents render it according to the suggestion (unless the content specifies another CSS rule that sets the value of the display
property). If a user agent does not follow the suggestion, this definition may produce incorrect results for this user agent.
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.
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.