Βι¶ΉΤΌΕΔ

Research & Development

Abstract

Live subtitles for television, which are produced using speech to text software, are inherently late compared to the audio that they represent. This delay can result in a less than ideal experience for the viewer. There is an opportunity to reduce this delay by exploiting the time taken by the broadcast encoder to encode the video for transmission. For the current Βι¶ΉΤΌΕΔ High Definition services this time is around five seconds, encoding the subtitles for broadcast takes much less than this and so the subtitles have a compensating delay to ensure pre-prepared, accurately authored, subtitles are synchronised with the audio. During programmes with live subtitles the compensating delay can be decreased which will reduce the delay of the live subtitles. This white paper describes a proof of concept that was carried out in September 2015 to assess the effectiveness and practicality of implementing this technique in a live broadcast environment.

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