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Does WCAG Require Live Captions?

Dec 21, 2022

If your organization publishes live video, you’ll need to provide live captions. 

The Web Content Accessibility Guidelines (WCAG) 2.1 Success Criterion (SC) 1.2.4, “Captions (Live)” requires captions for all live audio content in synchronized media. Synchronized media is defined as “audio or video synchronized with another format for presenting information and/or with time-based interactive components.” 

That definition certainly applies to most live videos that contain audio, unless a video is provided as a media alternative for text. Since WCAG SC 1.2.4 is a Level AA success criterion, you must meet this standard to provide your audience with a reasonably accessible experience (read more about the differences between WCAG Level A, AA, and AAA). 

Below, we’ll explain how organizations can fulfill WCAG’s live captions requirement and identify a few potential exceptions.

WCAG’s “Live Captions" requirement is essential for digital accessibility compliance

So, why are live captions important for digital accessibility? 

In short, if you’re publishing live content, it’s probably important — whether you’re demonstrating new products, answering customers' questions, or presenting sales data to shareholders, you’re “going live" for a reason. 

People with disabilities are part of your audience, and they’re entitled to important content. Live captions can improve experiences for a wide array of users including:

  • Deaf users and people with low hearing.

  • People with conditions that affect their memory.

  • People with attention disorders and other neurocognitive differences.

  • People who are learning a second language.

Some people may have access to assistive technologies (such as live caption software) that can generate captions from any audio source, but those captions aren’t always reliable. By providing accurate captions for your content, you can reach more people — including people who don’t live with disabilities who might prefer to keep their sound off. 

What types of media require live captions?

The “Live Captions" requirement is intended for broadcast media, not communications. In other words, if you broadcast a live product demonstration, you’ll need captions — but you don’t need to include captions for a two-way video call.

Other exceptions:

  • Audio-only broadcasts (such as live radio shows) do not require captions.

  • Video-only broadcasts do not require captions.

  • However, if video- or audio-only media remains on your website after the broadcast, you must provide an equivalent text alternative (such as a transcript).

Of course, you should always provide captions if possible, even if they’re not required for compliance. Remember, the goal of digital accessibility is to create a better internet for everyone — not to meet a certain level of WCAG conformance.

Related: Why Do I Need Both Transcripts And Captions for Accessibility?

Tips for Meeting WCAG’s Requirements for Live Captions

To fulfill WCAG’s requirements, most organizations work with Communication Access Realtime Translation (CART) services. 

CART services are also known as “real-time captioning.” Most CART providers employ human captioners, who use specialized stenograph machines and phonetic shorthand. The machine’s software converts the shorthand to text, which may be embedded in the video. 

Live captions can be written on-site or remotely. The cost of CART services varies greatly depending on the type of content and the technology used for streaming. Many services are quite affordable: Pricing starts at around $60 per hour for live captioning in English. 

While CART transcription can be extremely accurate, most live captions will contain a small number of errors. That’s an important consideration if you keep your videos online after the livestream: You’ll need to correct any errors in the captions to follow WCAG 2.1 SC 1.2.2, “Captions (Prerecorded).”

Related: What’s the Acceptable Format for Media Captions and Transcripts? 

Don’t rely on automatic captions alone

Artificial intelligence (AI) has come a long way, but currently, AI live caption tools aren’t reliable enough to meet WCAG’s requirements. While live human captioning isn’t 100% accurate, humans can understand context; auto-captioning software cannot. 

With that said, you can use automatic captions as a starting point for pre-recorded multimedia — just make sure you’re evaluating the output carefully. Great captions should contain all of the important audio from the video including music cues and sound effects.

For more guidance, download our free Video Accessibility Checklist eBook or send us a message to connect with a digital accessibility expert.

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