Non-Conformance Demo for WCAG 2.1 Success Criterion 1.2.1 Audio-only and Video-only (Prerecorded) (Level A)

1.2.1 Non-Conformance Shown with Non-Technical Explanation

1.2.1 Non-Conformance Example 1

1.2.1 Non-Conformance Example 2

1.2.1 Non-Conformance Explained

The video's purpose is to show parking lot flooding. Because there is no audio identifying what is going on, a blind or sufficiently low vision user would find either example inaccessible.

1.2.1 Non-Conformance HTML Markup and Technical Details

The following HTML markup in example 1 occurs beginning on line 31 of this page:

<p><video width="640" height="360"controls>
<source src="puddle.mp4" type="video/mp4">
if you don't see the video, your browser probably does not support the HTML5 video tag.
</video></p>

The video element was first introduced with HTML5. When reviewing videos marked up with HTML5, looking at the HTML markup can be a useful thing. In the markup above, there is a missing track tag. Strangely enough, none of the automated accessibility checkers I have tested flagged the missing tag, even though HTML5 was introduced back in 2014. I would have expected an automated accessibility checker to suggest that a caption track was necessary.

Even so, two things here would require manual review. First, though valid caption and audio description tracks are by definition machine-readable, no automated accessibility checkers can determine whether the track matches the video. Second, though HTML5 supports audio description tracks, very few media players do.

The problem in example 2 cannot be detetected by looking at the markup, only by reviewing the video itself.