Caption

What are Captions?

Captions are text overlays synchronised with video content, displaying dialogue and relevant sounds (like [doorbell rings] or [music playing]). They enable deaf and hard-of-hearing viewers to understand video content fully.

Captions differ from subtitles – subtitles translate dialogue for viewers who can hear but don't understand the language, while captions also describe non-speech audio.

Why Captions Matter

Accessibility

Approximately 11 million people in the UK have hearing loss. Captions make video content accessible to them.

WCAG Requirement

Captions for video are a Level A requirement under WCAG. All pre-recorded video content needs captions.

Legal Compliance

Accessibility laws increasingly require captioned video content, especially for public sector and large organisations.

Broader Benefits

Many people use captions in sound-off situations – commuting, in offices, at night. Captions expand your audience.

Types of Captions

Closed Captions (CC)

Can be turned on or off by viewers. The standard for web video. Usually provided as a separate file.

Open Captions

Permanently burned into the video. Cannot be disabled. Sometimes used for social media.

Automatic Captions

Machine-generated by platforms like YouTube. Often inaccurate, especially for accents, jargon, or multiple speakers.

Caption Best Practices

Accuracy

Captions should match the spoken word exactly. Summarising or paraphrasing loses information.

Timing

Captions should appear and disappear in sync with speech. Viewers need time to read them.

Speaker Identification

When multiple people speak, identify who's talking: [Sarah] "Hello everyone."

Sound Descriptions

Include relevant non-speech sounds: [phone ringing], [applause], [ominous music].

Readability

2-3 lines maximum. Break at natural pause points. Ensure sufficient contrast.

Creating Captions

Manual Transcription

Most accurate method. Watch the video and type what you hear. Tools like Descript or Rev help.

Automatic Generation + Editing

Use YouTube's auto-captions as a starting point, then correct errors. Faster than starting from scratch.

Professional Services

Caption providers like Rev, 3Play Media, or Verbit offer professional captioning.

File Formats

• SRT – Most common, widely supported
• VTT – Web standard, used in HTML5 video
• SCC – Broadcast standard

Platform-Specific

YouTube

Upload SRT/VTT files or use their captioning interface. Auto-captions need editing.

Social Media

Most platforms support caption files. Consider open captions for autoplay videos.

Your Website

HTML5 video supports VTT captions via the <track> element.