Captions, transcripts and audio description for product and marketing video

For a recorded video with sound, WCAG 2.2 at level AA asks for three things: captions for the audio (1.2.2), audio description of important visual information (1.2.5), and, at level A, either audio description or a full text alternative (1.2.3).¹⁴ In practice, for a product or marketing video, that means accurate captions, a script that says out loud what the video shows, and ideally a transcript on the page. Many short product videos can meet the description requirement simply by narrating what is on screen.³

The US Department of Justice names videos without captions among the barriers it sees on websites, and one of the enforcement actions it lists, against Teachers Test Prep, concerned captions for online video courses.⁹

What each type of media needs

This follows W3C's planning guide for audio and video.¹ There is one exception worth knowing: a video that only repeats text already on the page, and is clearly labelled as such, does not need captions.²

Captions

Captions are a text version of the speech and the non-speech sound needed to understand a video, synchronised with it.⁵ W3C's guidance on 1.2.2 says they should include who is speaking and meaningful sound effects, not only the dialogue.² For a product video, that might be "[upbeat music]" at the start, "[zip opening]" when the feature is shown, and the presenter's name the first time they speak.

Automatic captions are a draft

YouTube and other platforms generate captions with speech recognition.¹⁰ W3C is direct about them: automatically generated captions do not meet user needs or accessibility requirements unless they are confirmed to be fully accurate, and missing a single word such as "not" can reverse the meaning.⁵ Product names, sizes, materials and prices are exactly the words speech recognition gets wrong. Use automatic captions as a starting point and correct them.

Closed, not burned in

Closed captions can be turned on and off by the viewer; open captions are part of the picture and always show.⁵ Social clips often have open captions burned in, which is fine for a feed. On your site, closed captions in a separate file give viewers control. The usual web format is WebVTT (.vtt).⁵

Audio description

Audio description gives people who are blind, or who cannot see the video well, the visual information they need.⁶ A product video often shows the important part, such as the colour, how a fold-out mechanism works, or the size against a hand, without saying it. That is what needs describing.

The cheapest way to provide it is to write it into the script. W3C calls this integrated description: the presenter or voice-over describes the visual details as part of the main audio, so no separate track is needed.⁶ W3C also notes that a video of a person talking, with nothing important shown visually, does not need description.⁶ The note in 1.2.3 makes the same point: if all important visual information is already in the audio, no extra description is needed.³

Some practical script rules from W3C's guidance: plan description before filming, describe what matters rather than everything, stay neutral, and make sure on-screen text such as a discount code, a web address or a size chart is said out loud or provided elsewhere.⁶ If a video is already made and has no pauses for description, the options are a separately described version of the video or, for level A only, a full text alternative.³⁶

Transcripts

A transcript is the text of a video on the page. A basic transcript covers speech and important sounds. A descriptive transcript adds the visual information too, and W3C says it is required for people who are both deaf and blind; providing a descriptive one means you do not need a separate basic one.⁷ W3C suggests putting the transcript on the same page as the video, or linking to it directly below.⁷ The quickest way to make one is to export your corrected captions, remove the timings, and add the visual details.⁷

For a store, a transcript has a second use: it puts the product facts in the video into text on the product page, where every customer can read them.

Autoplay, sound and movement

• Sound: audio that plays automatically for more than three seconds needs a way to pause or stop it, or a volume control separate from the system volume (1.4.2, level A).⁸
• Movement: a muted background video that starts automatically, runs for more than five seconds and sits alongside other content needs a way to pause, stop or hide it (2.2.2, level A).⁴
• Controls: Shopify's theme guidance is not to autoplay media, to use native controls, to let Space pause playback, and to provide captions, descriptive audio and transcripts.¹³

Where to add captions on each platform

YouTube

In YouTube Studio, open Subtitles, select the video and add a language. You can upload a caption file, paste a transcript and let YouTube sync it, or type captions in.¹⁰ Check the captions there before you embed the video on your site.

Shopify

Shopify product media accepts uploaded videos (MP4, MOV or WebM, up to 10 minutes and 1 GB) or a YouTube or Vimeo link.¹² Shopify's product media help page does not mention caption files for uploaded videos, so if your product videos have speech, hosting them on YouTube or Vimeo with corrected captions and adding the link is the straightforward route. Put the transcript, or a text summary of what the video shows, in the product description.

WordPress and WooCommerce

The WordPress Video block has a Text tracks option for adding WebVTT files as subtitles, captions, descriptions or chapters, each with a label and language.¹¹ Choose the Captions kind for captions in the video's own language. The same block's settings include autoplay, loop and muted, and an option to show playback controls; leave the controls on.¹¹

A checklist for each video

1. Captions are present, corrected by a person, and include speakers and important sounds.
2. The script describes anything important that is only shown, or there is a described version.
3. A transcript, ideally descriptive, is on the page or linked directly below the video.
4. The video does not autoplay with sound; moving video can be paused.
5. The player can be operated with a keyboard and its buttons have names.

Automated tools can only check part of this. axe-core has a rule that flags a video element with no captions track,¹⁴ but no tool can tell whether captions are accurate or whether the narration describes what matters. Jralo's free check covers the automated part along with the rest of WCAG 2.2 A and AA, and notes which countries' accessibility laws are likely relevant to your site; the rest is a person watching with the sound off, and then listening with the screen off.