Live Captions for Public Meetings and Streams

Captions when there is no time to prepare them

A city council streams its Tuesday meeting. A resident who is deaf wants to follow the vote on the housing ordinance as it happens. A caption file made next week is no help to them tonight.

WCAG 1.2.4 (Level AA) requires captions for all live audio content in synchronized media. Live captions are typically produced by a trained captioner, often called CART (communication access real-time translation), by speech recognition, or by a combination, with a person correcting.

The Understanding document is specific about the target: broadcast-style live media such as webcasts and streamed presentations. It does not intend to require captions inside two-way calls in a web application; responsibility there rests with the content provider or the host of the call, not the application.

What acceptable live captions look like

• They are available for the whole event, from the first word.
• They convey speech, identify speakers where it is not obvious, and note sounds that matter.
• Delay is short enough that the text still matches what is on screen.
• Names of people, streets, dollar amounts and dates are right. Preload them to the captioner before the event.

Speech recognition alone is fast and cheap but weakest on exactly those names and numbers; a human captioner or a human monitor is the safer arrangement for public meetings.

Streamed council meetings, town halls and emergency briefings

Live video is where public bodies interact with residents in real time: council sessions, school board votes, emergency press conferences and public webinars. The pattern that creates a gap is "captions on request": the stream runs, nobody was booked, and the request arrives after the event ends. A standing arrangement (every public meeting is captioned) is easier to run than one made per request.

Stream page patterns

The embed on its own gives no hint of captions. Tell people where to find them and offer a text view if the player cannot show them.

<iframe src="https://stream.example.gov/live/council"
        title="Live council meeting"></iframe>

<iframe src="https://stream.example.gov/live/council"
        title="Live council meeting"></iframe>
<p>
  Live captions: turn on CC in the player, or follow the
  <a href="https://captions.example.gov/council">live text view</a>
  in another tab.
</p>

Announce captioning as a feature of the event, not a favor.

<p>Town hall, June 4, 6 p.m. Captioning available on request
with 72 hours notice.</p>

<p>Town hall, June 4, 6 p.m. Live captions are provided at
every session, in person and online. ASL interpretation:
request by June 1.</p>

When the recording goes up afterwards, it becomes prerecorded content and needs a reviewed caption file.

<video controls src="/rec/council-live.mp4">
  <!-- live captions never exported -->
</video>

<video controls src="/rec/council-live.mp4">
  <track kind="captions" src="/rec/council-live.en.vtt"
         srclang="en" label="English (reviewed)">
</video>

Apps and third-party platforms

A native app that embeds a public live stream passes the problem through: its player must be able to display the captions, and your controls must not hide them. Third-party streaming and meeting platforms carry captions in their own ways, so test the exact configuration you will use on the day. See vendors and third-party content for how third-party platforms fit in.

Testing: rehearse the real event

1. Run a private rehearsal with the same platform, the same captioner and the same names that will be on the agenda.
2. Watch it with the sound off. Can you follow speakers and votes?
3. Check that the captions control can be found and switched on with keyboard only, and on a phone.
4. During the live event, assign one person to watch the captions and fix a problem (a dropped feed, a captioner who fell off) at once.

Mistakes to avoid

• Relying on "we will caption it afterwards"; the criterion is about the live experience.
• Captions only in the room, not in the stream.
• No contact method for the captioner to receive names and terms beforehand.
• Treating a live audio-only radio feed as covered; the criterion concerns live synchronized media.
• Posting the recording with the live captions never reviewed.

Ship it when

• Every public live stream with sound has a captioning arrangement in place before it starts.
• Viewers can find the captions without asking.
• The recording is posted with reviewed captions.

Sources

• Understanding SC 1.2.4: Captions (Live) (W3C), opens in a new tab
• 28 CFR Part 35, Subpart H: Accessibility of Web Information and Services (eCFR), opens in a new tab

Standard version: WCAG 2.1 (W3C Recommendation, 5 June 2018), as named in the Title II web rule. This page is for informational purposes only and is not legal advice. For binding requirements, refer to the official ADA statute and regulations, and ask a lawyer how they apply to you.