Comcast Corp.'s IP-capable, cloud TV platform, called X1, will debut in Atlanta this week, as the operator prepares to launch it in five major markets by the end of 2012, company Chairman and CEO Brian Roberts said on Wednesday's earnings call.

Boston was the first market to get the X1. On the call, Roberts reiterated that Comcast will have X1 deployed to "hundreds of thousands of homes by the end of this year."

Comcast will use X1 to help bring some mojo back to a video platform that has been losing customers by the tens and hundreds of thousands each quarter. Comcast committed to the expanded rollout plan as it reported losing 176,000 video subs in the typically rough second quarter. To emphasize how bad the situation's been, the video losses in the second quarter were the best in four years for that period, and marked the seventh consecutive quarter in which Comcast showed improved video subscriber results. (See Comcast Q2 Profits Climb, Video Subs Fall .)

Comcast's not predicting when it might actually add video subscribers, but Comcast Cable President and CEO Neil Smit said the X1's "been very well-received in Boston" since its summer debut, and that the operator intends to bring the X1 experience (i.e. its cloud-based navigation system and apps environment) to all its high-end set-top boxes.

Pace plc is the first supplier of the X1 video gateway, but Comcast has already noted that it's porting the UI to the IP-capable RNG 150, an HD client box that's made by multiple suppliers. Comcast's heavily deployed RNG-class boxes can be "flipped" to support IP. Comcast is also believed to be working on an IP-only HD client box called the X3. (See Where Will Comcast's X1 Land Next? and Comcast Sizes Up All-IP Set-Top .)

Comcast was mum on where X1 would appear next after Atlanta, but Light Reading Cable reported in May that a handful of markets, in addition to Atlanta, are in line to get the service either later this year or in early 2013, including Chattanooga, Tenn.; Denver; and the Freedom Region, which includes systems serving Philadelphia, New Jersey and northern Delaware. (See Where Will Comcast's X1 Land Next? )

— Jeff Baumgartner, Site Editor, Light Reading Cable