Do not leave a media alternative unlabeled
Some pages carry a video that exists only to replay text already printed on the page, and the captions rule lets that video go uncaptioned on one condition. It has to be labeled as the alternative it is. F74 is the failure technique for skipping the label, which makes a match a defect rather than the exemption the page was counting on. The label has to name the text it stands in for, not merely announce itself as a video, and it works in both directions. Somebody reading the instructions can find the video, and somebody who lands on the video knows the text is the source and stops hunting for a transcript. W3C files this failure under a Level AAA media-alternative rule as well. And F74 only reaches pages that offer a media alternative to text in the first place, so an ordinary uncaptioned marketing video is a different finding altogether.
How we find it in an audit
The first question is whether the page offers a media alternative to text at all, because F74 cannot be raised anywhere else. Where one exists, we read the heading above the player, the link text pointing at it and any nearby copy, and check that the words name the specific text the video replaces. A reviewer then walks the page in source order twice, once as a reader who meets the text first and once as a reader who meets the video first, since the label has to work from both directions.
How affected users experience it
Deaf and hard-of-hearing users run on a rule of thumb, which is that a video without captions is out of reach. An unlabeled alternative makes that rule give the wrong answer twice. They skip a video that would have told them nothing new, and they never find out the page already said it in text they could read. The label is the whole difference between a dead end and a choice.
Passes vs. fails
Passes
<h2>How to assemble the desk</h2>
<p>Step 1, attach the legs...</p>
<h3>Video alternative to the assembly instructions above</h3>
<video src="assembly.mp4" controls></video>Fails
<h2>How to assemble the desk</h2>
<p>Step 1, attach the legs...</p>
<video src="assembly.mp4" controls></video>How this gets tested
The W3C publishes test rules that define what a checker looks for here.
- Video element auditory content has accessible alternativeA tool finds candidates, you decide
- Audio and visuals of video element have transcriptA tool finds candidates, you decide
The other techniques filed under this rule
8 guides on this site are filed under 1.2.2 Captions (Prerecorded). W3C documents this one as a failure of that rule, so it describes a way the rule gets broken rather than a way to pass it.
- G87sufficientAdd captions to every video with speech
- G93sufficientProvide open captions burned into the video
- H95sufficientAdd caption tracks to your videos
- SM11sufficientAdd caption text streams in SMIL 1.0
- SM12sufficientAdd caption text streams in SMIL 2.0
- F8failureDo not publish captions that skip dialogue
This guide is our interpretation of W3C technique F74: Failure of Success Criterion 1.2.2 and 1.2.8 due to not labeling a synchronized media alternative to text as an alternative. W3C publishes its techniques as guidance rather than as the standard, and says so on every one of them. The success criterion is what conformance is measured against, and a technique is one documented way to meet it.