Viacom said today it's planning to launch its own ad-supported streaming service by September 2018, the end of its fiscal year. The service will include "tens of thousands of hours of content" from across Viacom's library. From a report: Viacom had hinted about its plans in streaming before, but it shared a few more details on the call about what the service will include. The company, which owns cable TV channels like MTV and Comedy Central, already licenses some of its content to other streaming services like Sling TV and DirecTV Now, as well as newcomer Philo. "It's going to be rolled out in the U.S., in terms of the amount of content that it's going to have, it's going to have tens of thousands of hours of content that cut across the library we have on a global basis," the company said.