Improving the quality of live captioning

Wednesday, 28 May 2014 16:42pm

The recent initiative by the UK’s communications regulator, Ofcom, to measure the quality of live captioning has been welcomed by David Padmore, Director of Access Services at the major British caption provider, Red Bee Media.

Ofcom is requiring broadcasters to prepare four six-monthly reports on the quality of live captions on a sample of their programs from three genres: news, entertainment and chat shows. In the article ‘Ofcom and the continuous process of improving live subtitling services’ (captioning is called subtitling in the UK), Padmore discusses the results from the first sampling exercise. Most programs had higher than 98% accuracy, although quality was lower on chat shows, and the speed of captions was generally within Ofcom’s guideline of 160-180 words per minute.

The only area in which the captions fell markedly short of Ofcom’s guidelines was latency, or the time lag between the audio and the captions appearing on screen. Ofcom recommends a target of 3 seconds, but in the programs sampled the average was 5.6 seconds. “So what conclusion should we draw from this?” asks Padmore. “That subtitlers are working too slowly and we need to crack the whip? That broadcasters are wilfully ignoring Ofcom’s guidance? Or that the 3-second recommendation is an analogue-era bit of wishful thinking that does not reflect the current reality of live subtitling and the long and complex process of turning audio into text and displaying it on a digital TV screen?” Padmore believes that latency will remain the most intractable live captioning problem, “but I know that a lot of thought is going into how incremental improvements can be made and I would expect to see progress in this area as well”.

Padmore stresses that the report is based on a very small sample of 11 hours of live captioned programming when Red Bee Media alone produces about 165 hours every day. Nevertheless, he believes this first report provides a bassline, and the next three reports will show progress. “Along with Ofcom, we should all gather more evidence, seek to understand the issues as best we can and redouble our existing efforts to implement improvements.”

“Ofcom’s quality initiative has important implications for Australia,” said Chris Mikul, Media Access Australia’s project manager for television. “Captioning is now an international business. Red Bee Media’s Australian subsidiary provides captioning for SBS and the Seven and Ten networks, and any technological advances in the UK that lead to better quality will eventually find their way here.”

For more information, see Media Access Australia’s white paper, Caption Quality: International approaches to standards and measurement.

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