Subtitling technology specialist Screen Systems will be offering a realtime demonstration of their live web video subtitling solution at IBC. The company claims to have developed consistent subtitling for realtime/live WEB simulcasts – the ‘Holy Grail’ as far as subtitling on the web and OTT is concerned.
Last year Screen announced the development of a method for served web video playback to ensure that subtitles are always displayed in the position and style intended on web and OTT content, while allowing viewers to select from several language streams without the need to re-encode the video or host multiple copies of media.
A solution to subtitling live web video will now be demonstrated at IBC. One example is of a linear broadcast simulcast on the web. In a live web video the player cannot correctly report the current play position within the video, since this differs for each viewer depending on when they ‘switched on’. Additionally, each viewer may choose to pause or rewind the live video stream. Screen has therefore developed a different synchronisation mechanism, while still using image-based subtitles from a separate server.
In Screen’s solution, some low bandwidth timing information is added to the video stream and used to synchronise subtitles to the frames of video the viewer is watching. The ‘script’ at the viewer’s device can obtain the current frame's time value from the video stream and use it to determine when subtitles, should be displayed from the subtitle server.
The same general mechanism of image-based subtitles held on a separate server can be used for consistent broadcast quality subtitling of both video on demand and live web video.