Creating Accessible Video

Captioning Videos

Captions are written versions of audio content, displayed in time with the video, that ensure a video is accessible to users who are deaf or hard of hearing. They also help non-native English users understand the video and help users with cognitive disabilities better understand visual content.

Video captioning helps all users through these additional benefits:

• Helpful in loud environments where the audio can't be heard
• Allows users to experience content when they can't turn on sound
• Easier to understand by people who learn best through multiple modes (e.g., visual and auditory learning)
• Improves search engine results

Follow these best practices for WCAG 2.1 AA compliance:

Basics

• Do not use burned-in captions—they are not accessible—use closed captioning.
• Provide captions from the beginning to the end of the video.
• Identify all speakers.
• Describe all non-speech sounds, e.g., music cues, laughter, sound effects.
• Set off non-speech sounds in brackets.
• Provide captions for all spoken dialogue and important non-speech sounds.
• Ensure captions are synchronized with the audio.
• Don’t rely on auto-generated captions alone—edit for accuracy.
• Use high-contrast colors (minimum contrast ratio 4.5:1 against background) for on-screen text, titles, and graphics.
• Employ white text on a solid or semi-transparent black background and a clean, sans serif font such as Arial, Helvetica, or Verdana at minimum 16 pt
   

Timing and Positioning

• Synchronize captions to spoken words and other sounds.
• Make captions no more than 3 lines of text, viewable for 3 to 7 seconds per frame.
• Do not exceed 32 characters per line.
• Position captions at the bottom center of screen so that they do not cover important visual content, including lower thirds
• Users must be able to resize text up to 200% without loss of content or functionality.
   

Accuracy

• Spelling and grammar must be 99 percent accurate in relaying each speaker's exact words.
• Punctuation should favor clarity and accuracy over textbook style.
• Identify and preserve slang and accents.
• Use an easy-to-read sans serif font.
• Do not paraphrase.
   

How to Write Video Transcripts

A transcript is a text version of the video content that makes video content available to people who are deaf as well as users who have technical limitations and cannot watch the video. Users can also quickly scan the transcript for content of interest.

YouTube and Vimeo automatically create transcripts. For other video hosting platforms, check with your provider to understand how to create and display transcripts.

Basics

• Offer a full transcript of the video content.
• Include dialogue, speaker names, and descriptions of relevant sounds and visuals.
• Place the transcript directly below or near the video player for easy access.
• For interactive or multimedia-heavy videos, provide a descriptive transcript that conveys all meaningful information.

Clear Audio Descriptions

• Provide audio descriptions for essential visual information that isn’t clear from the audio alone, e.g., actions, scene changes, text on screen.
• If producing a new video, plan ahead to make the script inclusive by having narrators describe visuals naturally.
• If a separate audio description isn’t feasible, ensure the main audio conveys context.
• Record high-quality audio; voices should be clear and free of heavy background noise.
• Provide consistent volume levels across dialogue, music, and effects.
• Avoid overlapping voices or speech drowned out by music.

Multilingual Support

• Provide translated subtitles and captions where appropriate.
• Offer transcripts in multiple languages to reach larger audiences.

Testing and Validation

• Test videos with screen readers, keyboard navigation, and popular browsers.
• Validate captions and transcripts with actual users, including people with disabilities.

Checklist for Accessible Video

• Captions: accurate, synched, toggle-able
• Transcript available, descriptive if needed
• Audio description provided or integrated
• High-contrast, legible visuals
• Clear, consistent audio
• No harmful flashing effects
• Tested with assistive technology