Roku is best known as a maker of a set-top box that provides customers with access to streaming services on their TVs. But it's main business is actually licensing its technology to other companies who want to build connected televisions, and selling advertising against streaming content. And it sees Google as its biggest competitor in the race to build the dominant operating system for the future of television.

The company streamed over 5.5 billion hours of video last year, up 72 percent. That's triple what Amazon and Google did, and double Apple's numbers, according to Roku CEO Anthony Wood. He was onstage today at the Collision Conference in New Orleans, being interviewed by Verge editor-in-chief Nilay Patel. Roku has about 10 million active accounts right now, with most in the US, an audience growing roughly 50 percent a year. In a few years, Wood said, all TVs not made by Samsung are going to be powered by Roku or Android TV, the two biggest players licensing technology to smart TVs."

Amazon is a customer and a competitor

Right now Roku makes about half its money from selling its hardware and half from licensing and ad sales. But its media and licensing business is growing at a much faster rate. Right now Wood claims one-third of all over-the-top advertising is flowing through Roku's platform. "TV advertising is still in the stone ages," he said, referring to traditional broadcast television. Roku, by contrast, can allow marketers to target specific demographics and produce ads that are unskippable and interactive.

Plus, many of the millennials who make up Roku's customer base can't be reached any other way. "Just over half of Roku customers don't have paid TV subscriptions," said Wood. He believes Google is behind the recent push to "Unlock the Box," and he isn't a fan. Roku is available for $50 and can already be authenticated with many big cable companies to put a modern user interface on top of a cable subscription. "The problem the FCC is trying to solve, has already been solved," Wood said. He believes the push will add price for consumers, and disproportionately help big companies like Google.

Amazon wasn't totally left out of the conversation. "They are our biggest customer, but also a competitor," said Wood. Not only do they sell lots of Roku hardware, but they also pay to promote original shows. At the same time, Amazon is working on its own smart TV sticks, and hardware like the Echo that is meant to control every facet of the smart home.