YouTube Launches Live Captions at Google I/O

YouTube is launching captions for its live video feeds at Google (s GOOG) I/O Tuesday. The new feature will be unveiled with the Google I/O live video stream, but it’s also going to be available to any YouTube Live partner, according to Google’s Technical Program Manager for Accessibility Engineering Naomi Black. In fact, it could even be used by competing live streaming vendors to enhance their offerings.

YouTube has been providing automatic captioning of its vast library of content since early last year, using the same type of voice recognition technology that’s also at work on any Android phone. However, automatic captioning isn’t always accurate, and there’s no way for a publisher to correct automatically-generated captions in real time. That’s why the new YouTube Live captions feature relies on professional real-time captioning professionals instead of algorithms.

Google has hired a team of San Francisco-based Computer Assisted Realtime Transcription professionals to make sense of the spoken word during the Google I/O keynotes. “Working in teams on-site at I/O, they type at several hundred words a minute on specialized stenography equipment,” explained Black via email. She added: “We project the text on screens at I/O for the audience, and the text is also streamed live to an AppEngine gadget that delivers it to our website and YouTube channel.” Visitors to the site will then be able to translate the text in real time using machine translations.

YouTube officially unveiled its live streaming offering a month ago and has since given a limited number of partners a chance to broadcast their live video on its site. These partners will also be able to use the same AppEngine gadget, but they’ll have to work with and pay for their own live transcription service. Videos with captions will be searchable in full, which should give live streaming partners a considerable SEO bump.

Black and some of her coworkers are going to show attendees of Google I/O on Wednesday how they used Google’s AppEngine and YouTube’s API to implement live captions. The AppEngine gadget itself will be published as open-source code on Google Code, and Black told me it could theoretically also be used by YouTube’s competition. “We designed the gadget primarily to meet the needs of YouTube Live partners, but the code can easily be repurposed to work with other streamed text providers, and even other sites,” she said, adding: “You could use it on any website to provide live captions, regardless of where the video is hosted, or even without video at all.”