---
name: Captions
slug: captions
category: accessibility
status: published
created: 2026-08-21T00:00:00.000Z
modified: 2026-08-26T00:00:00.000Z
definition: Synchronised text for a video's audio, including speaker changes and
  meaningful sound, distinct from subtitles which only translate dialogue.
aliases:
  - name: closed captions
    source: community
  - name: open captions
    source: community
  - name: CC
    source: community
  - name: subtitles
    source: community
  - name: SDH
    source: community
  - name: burned-in captions
    source: community
  - name: live captions
    source: community
  - name: CART
    source: community
  - name: speaker identification
    source: community
tags:
  - media
  - sound
  - wcag
relations:
  contrastWith:
    - transcript
    - audio-description
    - sign-language-interpretation
  variantOf: []
  partOf: []
  seeAlso:
    - autoplay
implementations: []
sources:
  - title: "WCAG 2.2: Captions (Prerecorded)"
    url: https://www.w3.org/TR/WCAG22/#captions-prerecorded
  - title: web.dev accessibility glossary
    url: https://web.dev/learn/accessibility/glossary/
demo: inline
exhibit: false
useWhen: text that carries the sound of a video, not a translation
---

Captions carry the whole soundtrack, not just the words. Who is speaking, that a door
slammed off screen, that the music turned ominous, that the line was delivered in
Portuguese: everything a hearing viewer gets from the audio and would otherwise lose.
Subtitles assume you can hear and translate what is said, which is why a subtitle track
never says "[glass breaks]" and a caption track has to. The version marketed as SDH,
subtitles for the deaf and hard of hearing, is the format splitting the difference:
subtitle timing and styling, caption content.

Closed means the text ships as its own track the viewer can switch on, off, restyle, or
translate. Open, sometimes called burned-in, means the text is part of the picture and
nobody can turn it off, which is why social video defaults to it: most feeds autoplay
muted, and a large share of viewers keep captions on whether or not they need them. On
the web the closed form is a `<track kind="captions">` pointing at a WebVTT file, and
the player draws the cues; `kind="subtitles"` is the neighbouring value for the
translation case.

Live captioning is a different job with different tooling. CART is a trained
stenographer producing a verbatim transcript in real time, and automatic speech
recognition is the cheap approximation, good enough for a search index and routinely
not good enough for names, jargon, or crosstalk. Auto-captions left unreviewed are the
usual reason a caption track fails the people it was written for, and cleaning them up
afterwards is most of the work of captioning at all.

WCAG asks for captions on prerecorded video with audio at level A, and on live audio at
level AA. A transcript is a related but separate artefact: unsynchronised, readable on
its own, and the only route that serves someone who is both deaf and blind through a
braille display. Videos with no meaningful audio need neither, and marking those
correctly is part of the job too. When you write the cues, keep them short enough to
read at speed, break lines on phrases rather than mid-clause, name the speaker when it
changes, and put non-speech sound in brackets so it never reads as dialogue.