Do not skip captions when a video adds content
A video that was meant to stand in for text stops being an alternative the moment it starts telling you more than the text does. It becomes content in its own right. F75 is the failure technique for leaving that video uncaptioned, so a match here means the exemption the page relied on has lapsed. Captions are not the whole bill either. Once the video counts as content, the audio-description-or-media-alternative rule comes back with it, and so does audio description for prerecorded video, and both of those sit inside Level A and AA. Rewording is fine, for the record. A video will always phrase things differently from a page, and different phrasing is not new information. New information on the topic is.
How we find it in an audit
We play the video with the page text open beside it and note anything the video says that the page does not. Different wording gets waved through, because different wording is expected. What counts is a fresh fact, an extra example, a step the text never mentions. Where we find one, the finding covers captions and the description obligations together, since all of them land in the same moment for the same reason.
How affected users experience it
A deaf reader takes the page at its word, sees a video, and assumes it is the same material in another form. It is not, and the extra part is exactly the part they cannot reach. Blind readers lose the other half, where the video's on-screen detail was never written down and no description track exists to carry it. Both groups finish the page believing they got everything.
Passes vs. fails
Passes
<video src="interview.mp4" controls>
<track kind="captions" src="interview.en.vtt" srclang="en" label="English">
<track kind="descriptions" src="interview.desc.vtt" srclang="en">
</video>Fails
<p>Summary of the interview.</p>
<video src="interview.mp4" controls></video>
<!-- speakers cover topics the summary omits, and there are no captions -->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
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 F75: Failure of Success Criterion 1.2.2 by providing synchronized media without captions when the synchronized media presents more information than is presented on the page. 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.