Why is the HDMI output from streamed movies poor quality from the Surface RT 2 to a HDMI TV?

[Windows Central Question]

Streamed movies from the Microsoft Video App on the Surface 2 to a 1080P TV screen is very poor quality. The video shown on the TV is not nearly as sharp as the video on the computer's screen. It is much darker and with a splotchy appearance. Tried other TVs with the same result.