Transcripts of multimedia are essential for deafblind users

Deafblind multimedia users need everything in a machine-readable text format to be displayed via a screen reader in a refreshable braille device. Closed captions in videos are not usable text for them, because, though some modern braille readers can display the captions, the captions change too quickly to read them in real time as the video plays. Also, there is no easy way to access the captions separately from the video, even if the captions are in a text format.

A separate transcript to audio or video is the only way that multimedia content can be made accessible to deafblind users.
There are ways to create transcripts already, like placing transcript content into a separate markup containers after the multimedia content.

Problems

• Transcripts are not connected directly nor semantically to the <video> or <audio>.
• A connection via aria-describedby to the multimedia content is not usable for deafblind users, because it does not allow pausing or navigating the text in a screen reader. It makes the screen reader read the whole thing at once.
• A large transcript would need a skip link placed before it to make it possible for other users to skip the content.
• There should be an accessible way to show or hide the transcript for all users like there is for close captions (like through buttons in the UI of the multimedia element).

Why not allow a <transcript> element inside the <video> or <audio>?

To make this usable for all users we would need a button in the multimedia player to show/hide the transcript, something like there already is for close captions. This would ensure that there is always a semantic connection between the transcript and the multimedia content. A native HTML element would highlight the importance of a transcript for deafblind users who can't access multimedia in another way than text. Also search engines and their users could benefit from a semantically correct transcript.

References

• https://www.w3.org/WAI/WCAG21/Techniques/html/H96.html
• http://www.uiaccess.com/transcripts/transcripts_on_the_web.html