WCAG 1.2.2 captions: are burned-in open captions enough?

W3C lists success criterion 1.2.2, captions for prerecorded video with audio, at Level A. Burned-in captions are open captions that viewers cannot switch off, which suits platforms that drop sidecar tracks and costs you the viewer's ability to hide them.

What the W3C page says

The Understanding document separates closed captions, which the viewer can turn on or off, from open captions, which are part of the picture. For a file posted to a platform that strips caption tracks, open captions are the only form that survives the upload.

What Sume produces

POST /v1/video-captions burns captions into a new MP4 from a public HTTPS video URL for $0.20 per job on clips up to 60 seconds. It does not export or accept SRT; for a sidecar file your caption editor or another tool has to supply it.

If you publish both, keep the clean video and a burned-in copy. A restyle with source_caption_id reuses the first transcription, so a second look is a render rather than a second speech pass.

A practical rule

Burn in when the destination ignores sidecar tracks or when the captions are part of the creative. Keep a clean master so you can produce the closed-caption version where the platform supports it.