SIA-R38<video> element visual content has accessible alternative

Accessibility requirements

This rule tests conformance of the following accessibility requirements:

• 1.2.3 Audio Description or Media Alternative (Prerecorded)
• 1.2.5 Audio Description (Prerecorded)
• 1.2.8 Media Alternative (Prerecorded)

Description

This rule checks that <video> elements with audio have an alternative for the video content as audio or as text.

Applicability

This rule applies to every prerecorded <video> element that is visible, where the video contains audio.

Expectations

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

• <video> element visual content has audio description
• <video> element visual content has transcript
• <video> element content is media alternative for text

Assumptions

• This rule assumes that a mechanism is available to start the video and that the video element is not simply used to display the poster.
• 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 only a few implementations of video players (without third party technologies) that support audio description tracks at the time of writing.

Currently, the description track is not supported by most assistive technology. Accessibility support for the description track attribute is relatively low to non-existent. Video players may be able to work around the lack of support for the description track by using aria-live but few do this today.

Therefore, this rule does not consider description tracks as a valid way to provide an accessible alternative.

Examples

Acknowledgments

This document includes material copied from or derived from https://www.w3.org/WAI/standards-guidelines/act/rules/c5a4ea/. Copyright © 2024 W3C® (MIT, ERCIM, Keio, Beihang).