Comcast is adding a new wrinkle to its X1 network DVR service: Subscribers can now access their personal recordings out of the home on a mobile device, over any Internet connection.

Previously, X1 cloud DVR required subs to “sideload” content onto a laptop or mobile device. Now, “recorded programs can be accessed anytime, anywhere,” Matt Strauss, SVP and g.m. of video services for Comcast Cable.

Several years ago, TV networks and other content owners were overtly hostile to the concept of the network DVR. A consortium of programmers and studios sued Cablevision Systems in 2006 for copyright infringement before the operator had even launched its RS-DVR service, but the MSO prevailed after a federal appeals court deemed it legal.

At this point, that’s ancient history, and Comcast’s X1 cloud DVR has been rolled out to 50% of its footprint. But to stay on firm legal footing, Comcast is limiting out-of-home access to DVR recordings to one device at a time. The X1 cloud DVR provides up to 500 gigabytes of storage space and can record up to four shows at once.

On Wednesday, Comcast is launching X1 DVR with cloud technology — along with live in-home streaming of the TV lineup and DVR programs to tablets and other connected devices — in its San Francisco Bay Area and Houston markets. Previously, it rolled out network DVR and in-home streaming in Atlanta, Baltimore, Boston, Chicago, Philadelphia and Washington, D.C. Comcast expects to deploy the features to most X1 customers by the end of year.

Comcast will not disclose how many X1 subs it has, but according to Strauss the MSO is adding 20,000-30,000 X1 customers per day. All new triple-play packages include X1 service, along with some double-play offerings, he noted.

Comcast — whose $45 billion bid to acquire Time Warner Cable is pending regulatory approval — has called out its X1 project in making its case for the deal. The transaction will “bring Comcast’s best-in-class X1 platform and IP cable technology to the acquired systems — benefiting customers and programmers alike,” the cable giant said in response comments filed with the FCC last week.

Enabling live TV and DVR streaming required a massive data-center buildout, according to Elad Nafshi, VP video product management at Comcast. The MSO’s infrastructure supports recording and transcoding of more than 5,000 individual channels across the eight major markets where the X1 cloud service is deployed. To comply with the Cablevision RS-DVR ruling, Comcast stores each individual subscriber’s DVR recordings separately.

Also relying on the Cablevision RS-DVR ruling: Barry Diller-backed startup Aereo, which created a cloud-based streaming service for slinging live local TV and DVR recordings to users over the Internet. But Aereo was retransmitting over-the-air signals without permission — and the company, sued by major broadcasters, was effectively shut down after the U.S. Supreme Court ruled in June that it functioned like a cable system and was thus subject to copyright laws governing transmission rights.

With Comcast’s cloud DVR, recordings are stored both in the network and on customers’ X1G gateway devices. But the MSO also is rolling out cheaper Xi3 set-tops, which don’t have hard disks and have the ability to stream live TV and DVR recordings over IP, so eventually it could do away with traditional in-home DVRs.

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