F113Documented failure WCAG 1.2.5 Level AA Human testing required

Do not leave dialogue pauses empty of description

The video shows something the soundtrack never mentions, and the gaps in the dialogue where a narrator could have said it are left silent. F113 is the failure technique for that, and a match is a defect rather than a technique. What needs describing is a short list. Important actions, who is on screen, scene changes, and any text shown but never spoken. Not every gap is usable, though, and that is where the argument usually goes. A pause under about two seconds is too short to carry anything, and a pause landing nowhere near the moment it would describe is no use either. Some pauses ought to stay empty, because the sound in them matters more than the description would. Music is a smaller obstacle than people assume as well. Dropping the score under the narration, which the field calls audio ducking, turns a gap full of music into a gap you can use.

How we find it in an audit

A reviewer watches with the picture off first and writes down every moment where the audio alone leaves a question hanging. Then they watch again with the picture on, mark each gap in the dialogue, time it, and note whether it sits near the thing it would describe. Partial description gets flagged too, since a track that covers half the visual information and leaves usable pauses empty is still this failure. Where the gaps hold music rather than silence, the finding says so, because ducking is available and costs far less than a re-edit.

How affected users experience it

A blind viewer hears a long silence and knows something is happening. That is the maddening part. The soundtrack rolls on, everyone else reacts, and the moment passes with no way to find out what it was. On a training video the cost is concrete, because the step being demonstrated on screen is the step they came to learn. They reach the end with the narration and without the lesson.

Passes vs. fails

Passes: narration speaks the visuals. Fails: the offer is never spoken.

Passes

<video src="demo.mp4" controls>
  <track kind="descriptions" src="demo.desc.vtt" srclang="en">
</video>
<!-- or ship a version with the narration mixed into the soundtrack -->

Fails

<video src="demo.mp4" controls></video>
<!-- key steps are shown silently, and the pauses stay empty -->

How this gets tested

The W3C publishes test rules that define what a checker looks for here.

Video element visual content has strict accessible alternativeA tool finds candidates, you decide

The other techniques filed under this rule

11 guides on this site are filed under 1.2.5 Audio Description (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.

This guide is our interpretation of W3C technique F113: Failure of Success Criterion 1.2.5 due to not using available pauses in dialogue to provide audio descriptions of important visual content. 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.