Comcast adds live streaming to TV for Olympics digital coverage LOS ANGELES (Reuters) - Comcast Corp will launch its most ambitious digital video and on-demand effort yet for the Winter Olympics, using the games' vast audience to promote and test its newest viewing features for televisions, tablets and mobile phones. For the first time, customers with Comcast's Xfinity TV X1 set-top box can stream live all Olympic sporting events on their televisions, through an app called NBC Sports Live Extra, as well as on tablets and mobile phones. Other pay TV subscribers can access the app only through mobile devices. More than 1,000 hours of Olympics competition, from figure skating to curling, will be streamed live from the games in Sochi, Russia, starting February 6. The online content will supplement the more than 500 hours broadcast on Comcast-owned NBC and four of its cable channels. Another 200 hours will be available through video on-demand. For the Sochi games, Comcast will try out other new features. In some markets, NBC's prime time Olympics coverage will be available on-demand immediately after it starts, so that customers tuning in late can start at the beginning. A new feature called "SEEiT" will let people tune in to events being discussed online on Twitter. Xfinity X1 customers can click on a "SEEiT" button in a tweet to watch, or record, the event on their televisions. Others can switch to the competition on their phones or tablets. New Xfinity TV subscribers will receive immediate access to online and mobile content before any cable TV equipment is installed in their homes. Mobile and online viewing -- known in the industry as TV Everywhere -- surged during the 2012 Summer Olympics in London. NBC streamed events live for customers who logged in with proof of a pay TV subscription, and aired tape-delayed broadcasts on TV in prime time. The media company hopes new digital features will increase Olympics viewership and help familiarize customers with its most up-to-date digital and mobile technology, said Sree Kotay, chief software architect for Comcast Cable. With a large audience focused on the games for two weeks, "we think it's a fantastic test bed," Kotay said in an interview. NBC spent $775 million for rights to broadcast the Sochi games and executives say they expect to make a profit. The network had brought in more than $800 million in Olympic ad revenue as of early January, NBC said at a January 7 press event. Reporting by Lisa Richwine; Edited by Ronald Grover and Andrew Hay