This market concentration, said the analyst, will force new entrants to develop unique solutions in order to have an impact in this expanding ecosystem as OTT proliferates. Indeed it estimates that 86 million streaming media devices will be sold globally in 2019.

"Roku continues to lead streaming media device sales in the US with 34% of units sold in 2014. Google is second with 23%, and new entrant Amazon overtook Apple for third place," said Barbara Kraus, director of research at Parks Associates. "The market consolidation around these four brands forces new entrants to develop more creative features and functionality to tap into the strong consumer demand for streaming content."

Kraus added: "Devices with additional functionality such as the Intel Compute Stick may be a sign of things to come, where streaming is not the primary function but an extra feature to provide additional value."

The Streaming Media Device Landscape report shows that nearly 20% of US broadband households own at least one streaming media player such as a Roku 3, Amazon Fire TV or Apple TV.

8% own at least one streaming stick, such as a Google Chromecast, Amazon Fire TV Stick or Roku's HDMI Streaming Stick, while 2% own both form factors.

"Device shipments and sales receipts are important performance measures, but an equally critical metric for device makers is ongoing usage," Kraus said. "Usage will drive alternate revenue streams such as content sales and advertising. Roku devices are the most used among US broadband households that own a streaming media device at 37%, followed by Google Chromecast at 19%, Apple TV at 17% and Amazon Fire TV devices at 14%."