Creating Accessible Video
Captions are written versions of the audio content, displayed in time with the video.
Captions ensure that 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
- Allow users to experience content when they can't turn on the sound
- Easier to understand by people who learn best through multiple modes (e.g., visual and auditory learning)
- Improve search engine results
Follow these best practices for WCAG 2.0 AA compliance:
- Provide captions that are always visible
- Provide captions from beginning to end of video
- Identify all speakers
- Describe all non-speech sounds
- Set off non-speech sounds in brackets
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 so that they do not cover important visual content, including lower thirds
- 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 Caption Videos
Free services for captioning videos
For short videos, around 10 minutes in length, there are several free captioning services.
These tools automatically create captions using AI-powered subtitle generators. You will have to go through the text once it is generated because the way a certain word is pronounced or the speaker’s accent can often cause mistakes and correct any errors.
- Media.io Auto-Subtitle Generator
- VEED.IO Automatic Caption Feature
YouTube Automatic Caption: By default, you can upload videos that are up to 15 minutes long. Verified accounts can upload videos longer than 15 minutes.
Important: YouTube auto-captioning is not instantaneous upon upload. The videos are auto-captioned over time. If you need the video captioned immediately use the other tools mentioned.
These tools all are similar: videos can be auto-captioned, you can make edits to the captions, and then download the video with the captions intact. From there, host the video - e.g. YouTube or Vimeo - and embed the video onto your site. Captions appear on the video now.
Each service has limitations as a free service: some have caps on the individual video file size, some have caps on the combined length of videos captioned.
Manual captioning tools
Services allow uploads of videos where you can manually create the captions:
The interface is designed to make creating captions as simple as possible. Once captioned, the videos can be downloaded with the captions intact. From there, host the video - e.g. YouTube or Vimeo - and embed the video onto your site. Captions appear on the video now.
A transcript is a text version of the video content.
It 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 video content of interest.
Going through the process of captioning videos will also avail a transcript file as an output format. You can copy and paste the file text onto the page underneath the video.
Video hosted on YouTube and Vimeo
For all captioned videos, YouTube and Vimeo automatically create transcripts for users to access. There are no additional steps needed.
Video hosted by other providers
if your video is not hosted on either YouTube or Vimeo, you must check with your video hosting providers to understand how to display video transcripts.