Americans are quickly embracing the idea of being able to watch Netflix, YouTube and other online video providers alongside ABC, CBS, NBC, FOX, ESPN, TBS, Nickelodeon and the like on their wide-screen TV set. The NPD Group forecasts that by the first quarter of 2017 there will be a streaming media player in 39 million U.S. homes. That’s 40% of all Households, up from just 16% at the beginning of 2014. That’s now estimated at 24% and rising fast.

In its infancy, the streaming media player market was driven by growth from Apple TV and Roku, but over the past year and a half NPD says Amazon and Google Chromecast have made a significant impact. In addition to streaming media players, Internet-connected TVs, video game consoles and Blu-ray Disc players also deliver apps to viewers’ TVs. Among these four device platforms, though, streaming media players are forecast to contribute the most growth—and connected TVs the second most growth—in installed and Internet connected TV devices over the next two years. The forecast says this will drive the total number devices delivering apps to TVs up to 211 million by Q1 of 2017.

Not surprisingly, the increase in streaming media players helped boost the use of streaming video services. According to another NPD report, usage of Amazon’s Prime Instant Video service saw the greatest percentage point increase, and all of the top five video services benefited from the growing streaming media device market. Netflix still ranks first for app usage, followed by YouTube, Amazon, Hulu Plus and HBOGO.

Putting online video on the same big screen as broadcast and cable TV channels obviously improves the market for over-the-top (OTT) services. What remains to be seen is whether the business is additive or cannibalistic for existing media companies. New research by Parks Associates finds that 17% of U.S. broadband households are likely to subscribe to an OTT video service from HBO. Among these likely subscribers, 91% are currently pay TV subscribers, and roughly one-half would cancel their cable/satellite/telco service after subscribing to this HBO OTT service. That runs counter to insistence by HBO officials that the OTT service will have little impact on its MVPD subscriber base.

Over 50% of U.S. broadband households subscribe to an OTT video service of some sort, but Parks Associates analysts say this finding does not mean consumers are ready to abandon their televisions. “Television is not dying, but it is evolving. Linear video comprises only a slim majority of video viewed on the TV screen at 51%, and overall video consumption has shifted to on-demand sources. The age of appointment television is coming to a close, and programming will need to adapt to an on-demand environment,” said analyst Glenn Hower. Parks Associates reports the average head of household in a U.S. broadband household watches nearly 3.5 hours of OTT video each week on a TV set.