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.

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.