Closed captions vs. subtitles
People use the words interchangeably, but they're different tracks for different audiences. Knowing which one you need decides how you caption a video library.
The one-line difference
Closed captions assume the viewer can't hear the audio: they include speech, speaker labels, and sound cues like [applause] or [door closes]. Subtitles assume the viewer can hear but doesn't understand the language: they're speech only, often translated.
Where SDH fits
SDH — subtitles for the deaf and hard of hearing — is the hybrid: subtitle styling with caption completeness. If a service offers 'SDH subtitles', it means subtitles that include sound context.
What Vimeo's auto captions give you
Vimeo's Auto-CC produces closed captions: a same-language track generated during upload and labeled 'Autogenerated'. It doesn't translate. To serve other languages, you upload a separate subtitle file per language on top.
Which one a video library needs
For accessibility — and for any compliance target like WCAG 2.1 AA — you need closed captions on prerecorded video. For an international audience, you want subtitle tracks on top. The common case for an old Vimeo library is that it has neither; getting the closed-caption track in place is the first job.
Questions.
- Are open captions the same thing?
- Open captions are burned into the picture — always visible, impossible to switch off. Closed captions are a separate track the viewer can toggle. Vimeo's auto captions are closed captions.
- Do captions help with search?
- The caption track itself isn't page content, but a transcript is indexable text — and a captioned video keeps muted viewers watching, which is the engagement you actually control.