Captions (Prerecorded)

Why it matters

Captions carry the whole soundtrack for deaf and hard-of-hearing viewers. That soundtrack exists for them in no other form. There is a second group named in the standard itself, which is people who take written information in better than spoken. Plenty of hearing viewers turn captions on too, watching muted in an open office or beside a sleeping child. One thing captions are not is a translation. A subtitle track in another language still leaves out the sounds, so it is a service to your international audience rather than an accommodation for a deaf one.

Who this rule protects

Deaf and hard-of-hearing viewers rely on captions to follow the speech and everything else in the mix. People who take written information in better than spoken rely on the same text. So does anyone watching with the sound off, which on a phone in public is most people, most of the time.

How to check it yourself

1. 1Play every video that has sound and confirm captions exist and run in step with the speech. Turn them on where the player has a switch. Where they are burned into the picture and cannot be turned off, that passes just as well.
2. 2Check the captions carry all the dialogue, either word for word or in essence, plus every sound that matters. Condensing a long sentence is fine. Losing one is not.
3. 3Check speakers are named whenever more than one person talks. Meaningful sound effects should appear in brackets, written as [door slams] or [phone ringing].
4. 4Spot-check auto-generated captions against the audio in two or three minute stretches. Listen hardest for brand names, prices, numbers and the word not.
5. 5For music with no words, check the captions identify it well enough to be worth reading. Title, movement and composer, with the melody described, is the pattern the standard illustrates.
6. 6Where a video carries nothing the page does not already say, check it is labeled as an alternative to that text. Without the label, the exception does not apply and captions are due.

Failures we see most often

• A marketing video is uploaded with no caption track at all.
• Auto-captions are published unreviewed, so brand names, prices and negations come out wrong on screen.
• Captions carry the dialogue and drop the sound effects, so a viewer who cannot hear the alarm never learns there was one.
• No speaker label ever appears, so a panel discussion reads as one person contradicting themselves.
• A video is presented as the alternative to the page's own text and never labeled as one, so the exception it relies on does not apply.
• A video claims that exception while showing more than the page says, which means captions were due all along.
• Burned-in captions sit over the part of the picture the viewer needs to see, which is the one presentation rule the captions definition sets.

Who this one is for

Read from this rule's own note above, so the grouping and the note cannot disagree.

• Deaf and hard of hearingpeople who cannot hear the audio

How this one is tested

We list 1 ACT rule against 1.2.2. Each one defines exactly what a checker looks at, which is how automated tools decide what to flag. Each one also checks a slice, so passing every rule here is not the same as meeting the criterion, and a rule can be proposed rather than approved or need a person to finish it. The note beside each says which.

• Video element auditory content has accessible alternativeA tool finds candidates, you decide

How to fix it

• Add a caption track to every video with speech. In HTML that is a track element pointing at a WebVTT file, which is the format browsers actually read, so convert an SRT export before you ship it. Correcting the machine output before you publish costs far less than correcting it afterwards.
• Burn the captions into the picture where a track cannot travel with the file, which is the usual case for social video. Always-on captions pass this rule as cleanly as switchable ones.
• Caption the sounds, not only the words. Bracket the effects, name the speakers, and mark music with its title and its mood.
• Keep captions clear of anything on screen the viewer needs to read. Whether the captions themselves are legible against the footage is a contrast question rather than a captioning one, and it is measured the way body text is.
• Two lines at a time, timed within a beat of the speech, is captioning industry convention rather than a WCAG requirement. Follow it anyway. It is what makes captions readable at speaking pace.

Passes vs. fails