Okay, Still having the same problem. I know its been almost a year lol. I still want this to work, just haven't had the time, or feeling patient enough to mess with it lately. So according to all my research My Onkyo tx-nr609 is HDCP compliant, as well as my NVIDIA 970. Thanks for the suggestion of checking NVIDIA Control Panel though, because it led me to this...
For this screenshot I setup two displays, my tv which you can see on the left, and the Onkyo receiver which is selected on the right, this screenshot was taken using the HDMI that is connected directly from the PC to the TV. Again when I go to the receiver I get just a black screen (I feel like it is worth mentioning that if I select a different input on the receiver, one that has nothing plugged into it, I get a blue screen. not black). I did try different resolutions as well. I tried changing the default screen to the receiver as well. no luck. And then it says "Your graphics card and display are HDCP capable"... BUT then below you can see it says "ALERT: A repeater is connected to your system. Some video applications do not support HDCP when a repeater is present". This alert is not present when I click on the tv.
I'm not sure what is meant by a repeater... Is this potentially the problem? Or is this alert a standard thing you would see when you have pc plugged into a receiver plugged into a tv?
I do plan on upgrading the firmware for the receiver soon. I just need to find that dang USB stick...