Comcast (News - Alert) Corporation, the largest cable company in the United States, is debuting a new service that streams television shows and movies to current customers and will compete directly against Internet and video rivals such as YouTube (News - Alert), Hulu, and Netflix.

According to Comcast, the new service called, Xfinity Streampix, available this Thursday, will add to the 75,000 shows and films Comcast already offers consumers that subscribe to both TV and Internet service through Xfinity On Demand. For some users, including those that don’t purchase broadband from Comcast, the additional streaming service will be available as an add-on to their current package for an additional $4.99 per month.

“Xfinity TV is a one-stop source for the most video entertainment on any screen and it keeps getting better,” said Marcien Jenckes, Senior Vice President and General Manager for Video Services at Comcast in a press release. “Our goal is to consistently deliver greater value to our customers and to bring the best anytime, anywhere entertainment on multiple platforms. Streampix is another step moving TV everywhere forward by giving customers access to an even greater library of popular choices to watch,” she added.

Comcast currently has licensing agreements with companies including Walt Disney Co., Sony Corp.’s Sony Pictures, and Time Warner (News - Alert) Inc.’s Warner Brothers that will all be offering their content titles to the service. This will give viewers access to popular TV shows such as “30 Rock,” “Grey’s Anatomy,” “Heroes,” and “Married…with Children.” Viewers will also be able to stream movies such as “Brokeback Mountain,” “Ocean’s Eleven” and “When Harry Met Sally.”

In coming months, Streampix will provide streaming video service to multiple mobile devices, including tablets and smartphones. However, Streampix faces a steep challenge to make headway among competing streaming services since it is only available to Comcast consumers. Many Netflix subscribers probably would rather keep their subscription than have to change their television and Internet service providers to be able to stream Streampix content on demand.