It’s important that our audio-visual content is accessible to everyone. As a simple rule, all content should be presented to users in ways they can perceive.
We have a few tools at our disposal to help us do this.
1. Captions
Captions are text versions of speech and other audio content, that help make our video accessible to users who can’t hear all of the audio. They may be deaf, have limited hearing, or are simply situated in a noisy environment.
The caption content should:
- be sequenced to appear at broadly the same time as the audio content
- identify who is speaking
- accurately reflect the audio content by including both spoken words and meaningful non-verbal content that’s integral to the user’s understanding (for example, “laughter” or “lift dings”)
You can use the following conventions to distinguish the different types of audio content:
- apply square brackets to identify the speaker [Professor John Doe, Professor of Studies]
- apply square brackets and uppercasing for non-verbal content i.e. [AUDIENCE LAUGHS]
Example
2. Transcripts
A transcript helps deaf-blind users by providing a text-based description of a video’s content. This includes:
- spoken word
- non-verbal content, such as laughter
- visual information
A link to the transcript should be displayed alongside the video. A simple HTML page is the preferred format.
Incidentally, a transcript also helps search engines index your video content.
Example
Video content
Web Accessibility Perspectives: Video Captions (YouTube)
Associated transcript
| Audio | Visual |
| Video isn't just about pictures, it's also about sound. Without the audio, you would have to guess what this film is about | A man sitting at a desk starts watching a video on his computer. |
| [no sound] | The video on his computer shows a person speaking to the camera. It is playing with no audio. |
| Frustrating isn't it? Not knowing what's going on. That's the situation for everyone who can't hear. | The man watching the video has a hearing aid. |
Source: Example Descriptive Transcript from Caption Files (W3C)
3. Audio description
Audio description describes visually presented content that blind and visually impaired users may otherwise miss.
It can be added to the original video if there is adequate space in the soundtrack. However, where this isn’t the case, it may be necessary to produce an alternative version in which the video is paused to allow the audio description to be delivered.
Examples
The following example uses the original soundtrack with the audio description element added in real time:
Frozen – Trailer with audio description (YouTube)
The video is paused in this example:
Shop smart and use your rights - Extended audio description (YouTube)
Specific guidance for audio describing how-to videos
Audio describing a how-to video may seem challenging – for example, describing how to register for an account. However, the same simple rule of ensuring that all relevant visual content is also communicated audibly applies.
For example, if as the narrator you’re demonstrating submitting a web form, don’t say “click here”. Instead say, “click the button labelled Submit”.
Equally, when drawing the user’s attention to a specific section of the page, instead of saying “complete this section of the form”, say “scroll down to the section under heading ‘About You’”.
Example
Submitting edit suggestions on WAI webpages, using GitHub (YouTube)
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