Ever since the launch of YouTube in 2005, videos have become an essential part of the web browsing experience, and they're poised to grow even more in the future. This means, of course, that anyone concerned about website accessibility needs to have a solid plan for video. But making videos accessible isn't always as straightforward as simply including a transcript of the audio.
The Web Content Accessibility Guidelines (WCAG) 2.0 contain recommendations for making video content accessible. Guideline 1.2, which governs "time-based and synchronized media," provides the recommendations below.
Transcripts
All pre-recorded videos should have a transcript attached. Transcripts include not only the text of the words spoken in the video, but also the text of important words that appear on screen and important actions or changes of scene.
Transcripts are helpful not only to impaired users, but also to users who cannot view the video or who want to quickly look through the video’s content without watching it.
Captions
Although transcripts are an important first step in video accessibility, they aren’t always enough to offer an equivalent experience for users with hearing disabilities. Users relying only on a transcript must flip back and forth between the video and the transcript, which can cause them to miss important information, get distracted, or get lost.
For these reasons, WCAG 2.0 Level AA requires that all pre-recorded videos have closed captions available. Captions are similar to, but distinct from, subtitles. Whereas subtitles are merely a straightforward transcription of a video’s dialogue — often translated in another language — captions are usually explicitly intended for users with hearing disabilities. They contain a description of what is currently audible: dialogue, of course, as well as any sound effects or music playing.
Websites that broadcast live videos should provide real-time captions that allow users with hearing disabilities to follow and understand the video’s content.
Audio Descriptions
Audio descriptions are separate audio tracks containing speech that describes the action, characters, and scenes of a video. Users with visual disabilities listen to audio descriptions to understand the video’s visual content.
WCAG 2.0 Level AA guidelines state that all pre-recorded videos should have audio descriptions provided.
Media Players
Obviously, any media player used on an accessible website must include support for the three features above: transcripts, captions, and audio descriptions. Users must be able to toggle these features on and off as they desire while watching the video.
Many users with disabilities make use of navigational devices other than a mouse, such as keyboards or screen readers, to browse web pages. For this reason, users should be able to operate the media player without using a mouse. The player should also label its buttons and controls, so that users with screen readers can hear the name of each button and control and select the correct option.
Other Considerations
- Do not play videos automatically when the webpage loads. This can be confusing for many users, and the sound can interfere with other accessibility tools such as screen readers.
- Do not use videos that have more than three flashes within a period of 1 second, as this can provoke seizures in users with epilepsy.
