NEW YORK, August 11(Reuters) - A grandson of media mogul Sumner Redstone is launching an app that he hopes will help television companies, like the ones his family controls, attract young television viewers who spend as much time texting and posting about shows as they do watching them.

Tyler Korff, the son of Shari Redstone, who along with her father controls Viacom Inc and CBS Corp, is hoping his app will appeal not only to millennial users but also to TV networks scrambling to reach them as the target audience for most advertisers.

His app, called tvParty, lets users make comments, share photos and images on what is happening on-screen as a show progresses. If a user is watching later on-demand or through a streaming service, the app uses sound recognition to identify what show it is, and shares comments only when a viewer reaches the same point in the show at which they were made by other users.

That way, the service delivers something like a real-time conversation, which is becoming harder to do as more viewers switch to watching shows after they air, on their own schedule.

For example, an app user watching “The Real Housewives of New York City” two days after it aired will see their friends’ comments on the app at the point in time they made them during the show.

Korff, 31, and his business partner Joanna Kaufman, think reality TV lends itself more to social media as viewers tend to post while the shows are airing, as opposed to dramas when they mostly post after.

“We expect reality TV viewers to be the bulk of our audience,” Kaufman said.

By bringing people together around a TV experience, Korff is hoping his app will appeal to networks, who may wish to buy the data on users the app generates, or advertise shows on the app.

While TV networks such as Showtime have launched and subsequently shut down similar apps for their own shows, tvParty allows viewers to watch any show on any network, Korff said.

“People aren’t loyal to networks, they are loyal to content,” said Korff. “We are bringing them a one-stop shop.”

While there is no launch date set, Korff is aiming to have the app running in time for the highly publicized Aug. 14 return of “Bachelor in Paradise.”

Thirty-two percent of viewers browse a social network while watching TV, according to Deloitte’s 2016 Digital Democracy Survey, up from 26 percent in 2014.