Filed on behalf of John Paton RNIB (original email to RQTF list https://lists.w3.org/Archives/Public/public-rqtf/2020Nov/0016.html)

A couple of BBC Whitepapers may be of interest. The Impact of Subtitle Display Rate on Enjoyment Under Normal Television Viewing Conditionshttps://www.bbc.co.uk/rd/publications/whitepaper306 and Live subtitles re-timing proof of concepthttps://www.bbc.co.uk/rd/publications/whitepaper318. The second one is more for interest and the tl;dr version is that the video encoding for HD video takes about 5 seconds so by tweaking the workflow they can regain that time and reduce the lag between video and subtitles. I don't know if that is in scope for the requirements doc.