Charter Communications launched its mobile broadband service on June 30, and it's throttling all video streams to DVD quality.

"DVD-quality video streaming is supported. Video typically streams at 480p," Charter notes in the "Pricing & Other Info" section of its mobile sign-up page. The quality limit is similar to one just imposed by Comcast, which previously did not impose any video quality limits on its mobile service.

Comcast is letting existing customers get 720p video streams "on an interim basis at no charge," and the company announced plans to charge extra for longer-term access to HD quality. But Charter hasn't announced any plans to let customers stream in HD over its mobile service, for free or otherwise.

HD video "is not currently an option for Spectrum Mobile," a Charter spokesperson told Ars.

Charter and Comcast avoid competition

Charter's wireless plans are similar to Comcast's in multiple ways, which is no surprise as the companies this year agreed not to compete against each other in wireless and are cooperating on operational aspects of their services. Comcast and Charter are by far the two biggest cable companies in the US, but their residential cable services don't compete against each other in any individual city or town. Each company is limiting its wireless service to its cable territory.

Since Comcast and Charter don't operate their own cellular networks, they are both reselling data from Verizon Wireless. Verizon offers resellers options to limit the speeds of video resolution and hotspot usage. Verizon hasn't said exactly how it identifies video streams, but you might be able to avoid the limits by using a VPN.

The Charter and Comcast video limits are likely not related to the recent repeal of net neutrality rules. The rules banned throttling, but they had an exception for "reasonable network management," and the major wireless carriers have enforced various video and hotspot limits for several years without being punished.

Charter and Comcast charge similar prices

Charter is selling "unlimited" data for $45 a line, the same monthly price as Comcast. While Comcast charges $12 for each gigabyte of usage on its limited plans, Charter is charging $14 for each gigabyte.

On the unlimited plans, both Comcast and Charter are reducing speeds for all types of Internet usage after customers use 20GB in any given month. Charter's unlimited plan includes 5GB of high-speed mobile hotspot usage each month, and it reduces tethering speeds to 600kbps afterward. (Comcast's unlimited plan limits tethering to 600kbps at all times.)

On the by-the-gigabyte plans, both Charter and Comcast allow tethering at high speeds.

Only Charter home Internet customers can sign up for the company's new mobile service.

"If a residential Spectrum Internet subscription isn't maintained, an additional $20 per-line monthly charge will be applied and Spectrum Wi-Fi speeds will be limited to 5Mbps," Charter says, referring to its network of public hotspots. "You can change your rate plan, but you won't be able to add additional lines."

Disclosure: The Advance/Newhouse Partnership, which owns 13 percent of Charter, is part of Advance Publications. Advance Publications owns Condé Nast, which owns Ars Technica.