Audio and Video
Audio and video are inaccessible to people who can’t hear or see them, so it’s important that we always provide alternatives for multimedia content.
Accessible Audio
To make audio accessible, always provide a transctript. If there are multiple speakers involved, you can identify each speaker in the transcript.
Accessible Video
Captions
The terms "captions" and "subtitles" are used interchangably in different regions of the world. Captions provide a textual transcript of the video's dialogue and other sounds (sound effects or music) while subtitles are spoken audio of a video translated to a different language. Captions are necessary for accessibility. Subtitles on the otherhand are not directly an accessibility accommodation but helpful for inclusion of users of other languages.
A guide to the visual language of closed captions and subtitlesDescription of visual information
Audio description is additional commentary explaining what is happening in a video that help blind and visually impaired users to better understand a video. If you are not sure what audio description is, watch this Frozen film trailer with audio description to help you get an idea.
Avoid causing seizures
Avoid anything that flashes more than three times in any one second period. This includes strobe lighting, flashing images, some animations, etc. Photosensitive epilepsy can be triggered by flashing images in videos. If flashing images cannot be avoided in a video due to the content or type of video created, provide an advance warning to the user.
Consider accessibility of videos with only visuals
Some videos are created for visual users with or without music in the background. If this is the type of video you want to create, think about how this can be made accessible to user who is visually impaired. Could you record audio of the messages on screen? Could you provide a transcript or a description of the video content?
Use of colour
When you are creating a video, especially where text messages are displayed, consider the colour contrast. Read more about accessible colour contrast. Make sure your videos are accessible to people with colour vision deficiency by not differentiating information only by colour.