ACT Rule 4c31df · proposed
Audio or video element that plays automatically has a control mechanism
This checks that media playing automatically comes with a way to stop it or mute it.
A tool can decide this one on its own, which is why it turns up in scanner output. The rule is proposed, so it has not yet been implemented in full by a tool and reviewed by a W3C working group, and the wording can still change.
Why passing this rule settles nothing about WCAG
W3C's requirements mapping for this rule names no WCAG success criterion as a conformance requirement. That is the position of 24 of the 87 live rules and this is one of them, which is why a scanner can flag it while an auditor leaves it out of the findings. Both of them are reading the same page correctly.
W3C combines this rule with the three second rule in the composite Audio or video element avoids automatically playing audio, and the composite is what answers to 1.4.2. The control also has to work for everyone, and W3C warns that browsers' own media controls are not always reachable by keyboard.
Where W3C files this rule
W3C's index lists this rule under the criteria below, which is how most readers arrive here. The rule's own page names none of them as a conformance requirement, so treat the grouping as a signpost rather than as a verdict.
- 1.4.2 Audio Control Level A
The composite rule this one feeds
This is an atomic input rule, which is why it names no criterion of its own. W3C combines its outcome with the other inputs below, and it is the composite that maps to WCAG. A report that cites this rule id alone has told you about one ingredient, not about the dish.
- Audio or video element avoids automatically playing audio A tool can check this
The normative rule text lives at W3C
What the rule applies to, and exactly what it expects, is published by W3C and can change. We link to it rather than restate it, so nothing here can quietly fall out of date against the source. Read rule 4c31df at W3C.
Audio or video that starts on its own must be stoppable
Audio that begins without being asked for competes with a screen reader, which is also speech. The person cannot hear their own software over your video. They often cannot find what to press to stop it.
The rules give you two acceptable ways out. Keep it under three seconds, or give a control that stops it and put that control where it can be reached first.
Background video with an audio track is the usual source, especially when the only stop control is far down the page. Users cannot stop it, and it blocks their screen reader.
Fixes that satisfy it
If this rule fails on your site, these are the techniques that put it right.
Other rules W3C files under the same criteria
Each of these asks a different question about the same part of the standard. Passing all of them is still not the same as satisfying the criterion.
All 87 ACT rules are grouped by the criteria they test, and 24 of them decide nothing about WCAG on their own. Run a free scan to see which of these your own pages trip.