A new report by researchers at Northeastern University confirms that the nation’s four major wireless carriers throttle at least some video content on their networks, and suggests a few workarounds for those who want the best possible video quality on their mobile devices.

AT&T, Sprint, T-Mobile, and Verizon all note on their websites that their cheapest "unlimited" plans only allow DVD-quality video. For example, AT&T's cheapest advertised unlimited plan, the $40 AT&T Unlimited & More plan, only allows you to stream video at 480p resolution---DVD quality. If you want high-definition streaming, you'll need to pay an extra $8 a month for the AT&T Unlimited & More Premium service.

The Northeastern report comes a little more than a year after Obama-era Federal Communications Commission rules that prohibited telecom companies from throttling, blocking, or otherwise discriminating against lawful content lapsed, after the Trump-appointed FCC voted to repeal them.

The report, based on crowdsourced data from the researchers’ mobile app, suggests that carriers limit video quality by throttling the speeds of video connections. For example, the researchers found that AT&T capped video connections at 1.5 Mbps on the cheaper unlimited plan, as a way to limit users to “DVD quality” streams.

But throttling is a blunt way to limit video quality. YouTube and some other video providers will serve 480p or lower resolution video instead of high-definition video if they detect that a user has a slow connection. In cases where a video provider doesn't offer a lower resolution alternative, you might simply end up with a choppy connection instead of a lower quality stream.

Google Fi is the only US-based mobile service for which the researchers gathered data that didn't throttle video streams. Google Fi essentially resells service from Sprint and T-Mobile. But it doesn't offer unlimited plans. Instead of a flat monthly fee, you pay for the amount of data that you actually use, meaning Google has less incentive to throttle video streams. Other services that don’t offer unlimited plans might not throttle data, but some do. For example, a spokesman for Ting, a wireless reseller that uses T-Mobile and Sprint's networks, says Ting doesn't throttle any connections, but that T-Mobile throttles Ting connections.

The FCC and the Department of Justice have both signed off on a merger between T-Mobile and Sprint, which will reduce the number of major US mobile carriers from four to three.

Carriers that limit the quality of video often do so by scanning data in the transmission identifying it as a video. To get around that, you can try using a virtual private network (VPN). These services route all your internet traffic through their own servers over encrypted connections so that carriers can't tell whether you're streaming videos.

Sometimes, carriers aren’t the only ones to blame for lower-quality video. The report notes that some apps, including Amazon and Netflix, stream video at a lower resolution than 480p by default, but you can usually change this. And even “unlimited” plans often have limits on the total amount of data you can download over a specific period. For example, the fine print for Verizon's Do More Unlimited plan says you can use 50GB of data per month, after which your connection might be slowed in times of congestion.

Blunting Traffic

Throttling connections based on specific types of content violated the FCC's Obama-era net neutrality rules, but the Republican-controlled FCC voted to jettison those rules in December 2017. Northeastern University researcher David Choffnes told WIRED last year that his team found that the four major carriers began throttling video well before the FCC's rules expired in June 2018.