SIA-R31`<video>` element content is media alternative for text

Accessibility requirements

This rule is not required for conformance to any accessibility requirements.

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

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

All the information contained in each test target is available as text that is visible and included in the accessibility tree.
Each test target is labeled as a video alternative for text on the page. This label is visible and included in the accessibility tree.

The term label does not refer to the <label> element.

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.

This rule has no known accessibility support concerns.