Offer a described version of every video
Audio description is narration filling in what the picture shows and the soundtrack does not. G173 delivers it as a second version of the video rather than a second track, because user agents cannot be relied on to let people switch tracks. The description covers actions, characters, scene changes and on-screen text that matters. It goes into the pauses in dialogue and sound effects, and that is the practical limit. A dense scene with wall-to-wall speech leaves almost no room to describe anything. W3C lists this as sufficient for 1.2.3 Audio Description or Media Alternative at Level A and for 1.2.5 Audio Description at Level AA, in both cases reached through a more specific technique. So it is the umbrella instruction, and something concrete has to sit under it.
How we find it in an audit
Our reviewers watch each video with the screen turned off and note every moment the audio alone leaves a hole. On-screen instructions. Unnamed speakers, charts referred to only as 'this'. Then we look for a described version, check that it is offered next to the player rather than hidden, and listen to see whether the narration actually fills those holes.
How affected users experience it
A software demo whose presenter says 'just click here' is a demo with the instructions taken out. The listener hears confident narration and learns nothing they can act on. Audio description turns 'click here' into 'she opens Settings, then Privacy, and switches off tracking', which is the same information everyone else was getting from the screen.
Passes vs. fails
Passes
Next to the player sits 'Watch with audio description', a version whose narrator adds 'She opens Settings, then Privacy, and switches off tracking.'
Fails
A product demo where the presenter says 'just do this' while clicking through menus, with no described version and no transcript.
How this gets tested
The W3C publishes test rules that define what a checker looks for here.
- Video element visual content has accessible alternativeA tool finds candidates, you decide
- Video element visual content has strict accessible alternativeA tool finds candidates, you decide
Other ways to satisfy this rule
13 guides on this site are filed under 1.2.3 Audio Description or Media Alternative (Prerecorded). W3C lists this one as sufficient for that rule when it is implemented through a more specific technique, so the condition is part of the test rather than a footnote to it.
- G8sufficientProvide a version with extended audio descriptions
- G58sufficientPut the media alternative link beside the media
- G69sufficientProvide a full transcript of the media
- G78sufficientOffer a selectable audio description track
- G203sufficientDescribe talking-head video with static text
- G226sufficientNarrate visual content within the soundtrack itself
This guide is our interpretation of W3C technique G173: Providing a version of a movie with audio descriptions. 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.