Ofcom has previously slammed broadcasters for slow and inaccurate subtitles.  Image: Ofcom
Ofcom has previously slammed broadcasters for slow and inaccurate subtitles.
Image: Ofcom
BBC viewers have been promised that a new subtitling system developed in partnership with Ericsson will finally end the lag between characters and presenters speaking and subtitles appearing.

In 2014 research undertaken by broadcasting regulator Ofcom revealed that subtitles took an average of 5.8 seconds to appear on screen, almost double the recommended 3 seconds.

Delayed subtitles are a source of high complaints for all broadcasters, with many viewers and stakeholders saying the problem spoils their enjoyment of programmes.

The new Ericsson system, devised in partnership with BBC R&D, is promised to minimise the delay by better synchronising the subtitles’ play-out with the programme’s audio.

According to Ericsson the new approach achieves this “by utilizing the time taken to compress the audio and video streams for transmission and distribution.”

The tech firm says because captions take less time to encode, a compensating delay is used to ensure they’re synchronised with the audio. During programs with live captions this compensation can be decreased, significantly reducing the apparent delay.

BBC channels will start using the new system from summer 2016 and Ericsson will also be offering the service to other broadcasters.

Thorsten Sauer, Head of Broadcast and Media Services, Ericsson, says: “The inherent latency of live caption delivery is a challenge for broadcasters the world over.

“Our aim has been to improve this experience by leveraging our significant expertise in both language services as well as compression and our overall research in the media space.

“Together with the BBC we believe we have made some very significant advancements in the delivery and quality of live captioning and set a new bar for the future of the industry.”