I finally got the Display Port to work with Media Center in 7, 8.0, and 8.1
What I did was after activating the card I went into the media center Extra Galleries and there was a cable logo labeled Digital Cable Advisor to activate it and it worked.
This suggestion does not work for me. I still get the "Display driver error; The video playback device does not support playback of protected content" error message on any DisplayPort screen for protected shows. WMC will play unprotected content (e.g.
most broadcast TV), but not flagged/protected shows (e.g. HBO) over a cable that terminates to a DisplayPort plug.
My guess is that rmjohnson144 was testing with unprotected recording, or is going from a DisplayPort out on his PC to an HDMI in on whatever display/monitor. (That scenario has never been a problem.) The crux of this unresolved bug is
how to go from DisplayPort out to a monitor's DisplayPort in and successfully play a protected recording.
I have HBO so it works with protected video. It is also DP to DP. I had it working on my GTX 780 if that matters. I currently use a R9 390, but don't have MCE installed as I currently run Win10.
It was very tricky to get working, but only required activating the cable card and then activating the Digital Cable Advisor last. I always had to do this one last. But configuring the MCE was a pain, but once I knew it worked then I just kept fiddling
with it until it came back on again. I usually reinstall windows twice a year or more depending. I always get malware and reinstall instead of removing it. I usually just have reinfections soon after removal, but reinstall keeps them at bey for 6-months
or so.
Also, I work with a clean slate. Windows is always a fresh install. Maybe other things are interfering?
Maybe I'll try again with my spare SSD as I'm currently using Windows 10. I use Silicon Dust HDHR3 tuner with it's current app and it works fine. Maybe the VLC I have to have installed first affects WMC? That is the only thing I do before installing MCE
on my fresh installs, beside windows update and driver installs.