Providing an Equivalent Experience Around Captions

Last updated: 5/23/2025

The following recommendations will help you provide a more equivalent experience with captions:

Avoid fully relying on AI captioning if its quality is too low, especially in regards to caption segmenting (i.e., edit AI captions when necessary)
- Jump to avoid AI captioning rationale
Ensure caption text is of a large enough size to be easily read
- For example, 12-14pt minimum (or the Storyline equivalent, 125-150%)
- Jump to caption text size rationale
Do not allow captions to obstruct visibility of any non-decorative course content
- Jump to captions not obstructing visibility rationale

Avoid AI captioning rationale

Keep in mind that we provide captions not only to meet the WCAG 1.2.2 Captions (Prerecorded) (A) requirement but also to ensure that learners who have hearing disabilities can have an equivalent experience around consuming audio-based information.

Caption quality has a major influence in this regard, especially caption segmenting.

For example, if individual caption segments contain part of one sentence and part of another, then a learner's ability to understand either sentence relies on the learner remembering some content from segment to segment; that requires more mental effort and its a notably different experience compared with how learners receive audio information, since the audio likely pauses between the end of one sentence and the beginning of the next, rather than pausing at some arbitrary point mid-sentence. Whereas, if each sentence is offered through its own caption segment, learners can more easily understand each sentence and experience them in a way more equivalent to how listeners experience them.

You won't always be able to fit individual sentences within single caption segments — longer sentences may need to be spread across multiple segments due to other considerations — but by keeping clauses and ideas together within caption segments (to the extent you can), you'll similarly make it easier for learners to understand what the captions are conveying.

So, when a sentence ends, so should its caption segment; start the next sentence in the next segment (except when the previous sentence is less than ~1.33 seconds, as explained further in the Captioning best practices page). And, if you need to divide sentences across multiple segments, aim to separate them at punctuation, natural pauses in speech or in other ways that keep clauses and ideas together as much as possible.

This rule is especially important to note because many AI captioning services/features, including autocaptioning of Storyline's text-to-speech audio, frequently commit this error: including a word or two from one sentence at the end of the previous sentence's segment. You may need to manually edit such segments or altogether avoid using AI captioning for this reason.

Caption text size rationale

In order to have an equivalent experience, learners should be able to read caption text with the same relative ease with which they can listen to the corresponding audio. After all, learners typically do not have to strain or exert extra effort to hear eCourse audio, so why should they have to squint, lean forward or otherwise exert extra effort to read eCourse captions?

Captions not obstructing visibility rationale

Learners who do not rely on captions can view and engage with all slide content while simultaneously consuming the slide's audio-based information; thus, in order to have an equivalent experience, learners who rely on captions must also be able to view and engage with all slide content while they're simultaneously consuming the slide's audio-based information — that is, while captions are displayed — which means that caption segments cannot obstruct view of any non-decorative slide content. However, it is acceptable for caption segments to partially obstruct the view of in-slide buttons so long as the button text remains fully readable and a large enough portion of the button's clickable area remains unobstructed enough that the button can reasonably be used.

Also, note that while WCAG 1.2.2 does not explicitly mention this consideration, WCAG's caption definition in its 4th note, does share this same guidance.

Make sure to test for captions obstructing non-decorative slide content across as many different display resolutions or monitors as possible, as each learner's display settings will influence the size at which captions appear relative to other eCourse content.

Electronic Accessibility