There are numerous HDMI Splitters/Amplifiers from a particular auction site or popular online shopping site that either intentionally or unintentionally strip HDCP from a HDMI feed.
The legalities that surround this are very clear and how you want to proceed is up to you.
I am not advocating their use but I do know that is one way to solve one of the issues you are currently facing.
I will check the decimator now to see if the resolution will adjust from 1600x900 for you.
/Edit
I tried the resolution into the decimator from 2 separate laptops and strangely it states it is getting a 1920x1080 50p resolution from the Laptop even though it is set to 1600x900 50p Hz.
See the photos below: