NPD, in its Connected Home Forecast, said that by the end of 2019, there will be 238 million installed devices connected to the Internet and able to deliver apps to TVs, representing 59% growth from 2015 to 2019. Connected TVs will continue to be a key source of growth.

The research firm said connected TVs are will drive 45% of the growth over the coming four years, while less expensive, content-heavy streaming media players from Roku and Google’s Chromecast are projected to drive 35% growth.

Users will also be accessing their video services from an array of other handheld devices such as tablet computers and smartphones.

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“With an ever-increasing number of connectable devices expected to be connected to the Internet, viewers will have the ability to choose their preferred option instead of using the only device they have attached to their TV,” said John Buffone, executive director, industry analyst, NPD Connected Intelligence, in a release.

Driven by hardware prompting connectivity, an increase in quality app programming from TV networks, and improvements to user interfaces, the study suggests the rate of connecting these devices is forecast to increase from 70% in 2015 to 80% of installed units by the end of 2019.

Streaming media devices will also play a dominant role in the consumer viewing experience. Now that customers have access to various streaming device options from Google, Roku, Amazon and Apple, NPD expects 43% of U.S. Internet homes will own at least one streaming media player by the end of 2019.

Interestingly, Roku and Google Chromecast have been expanding their presence beyond selling standalone media players by working with TV manufacturers to embed their app into the TVs themselves.

As media player companies partner with TV manufacturers, it has kicked off a consolidation of operating systems. NPD said that over 10 TV manufacturers have opted to partner with Roku and Chromecast, as opposed to managing their own app ecosystem.

Roku has clearly been very aggressive on integrating its apps into TV sets. In January, Roku hatched a plan with hardware partners TCL, Hisense and Haier to introduce 60 TV models that incorporate the company’s streaming platform built into them this year, for example.

“The integration of streaming media player operating systems into TVs points to the beginning of a consolidation of operating systems that app developers will need to focus on in order to reach their audience,” Buffone said.

These partnerships make sense for TV manufacturers as it creates convenience for customers that may already have an existing Roku device or Netflix subscription. Customers will be able to turn on the TV and then log into these apps by entering in their credentials.