What had been a wide-open market for OTT ecosystems just a few years ago is now a lot more decided.

Roku and Amazon Fire TV have increased their dominance over the U.S. streaming media player (SMP) market and now control nearly 70% of it, according to a Parks Associates ranking of the top OTT systems in the first quarter.

Market leader Roku controlled 39% of the installed base of SMPs at the end of Q1, according to Parks, representing narrow growth over the 37% in controlled in the first quarter of 2017.

No. 2 platform Amazon Fire TV controlled 30%, growing from 24% two years prior.

"The adoption of Roku and Fire TV streaming media players continues to grow at the expense of Chromecast and Apple TV,” said Parks Associates Senior Analyst Craig Leslie.

Related: Roku Will Soon Have 70% More OTT Devices in Global Streaming Market Than Next Closest Competitor

The race between Roku and Fire TV has been a bit subjective recently. Amazon recently announced 34 million regular users for its Fire TV platform worldwide, compared to 29 million announced by Roku at the end of the first quarter.

In May, research company The Diffusion Group said both platforms were about evenly distributed. But last month, another research company, Strategy Analytics, made a seemingly out-there declaration that Roku was the king of the OTT world, controlling 70% of the world’s connected video devices.

It does seem clear, however, that Roku and Fire TV are now the fundamental OTT platforms that video companies must develop apps for—as iOS and Android are in the mobile world.

Also notable from the new Parks study, titled “360 Deep Dive: Adoption and Use of Connected Video Devices,” as of Q1, 39% of U.S. broadband homes owned a SMP, which is only 1% growth in one year.

Such slight market growth has to be concerning for the myriad companies out there with new OTT launch plans.