I have blackmagic UltraStudio 4k, and LG UHD tv. I connected with HDMI cable capable of 4k,30Hz transfer.
I use final cut pro 7, final cut pro X with this setting, and it works.
Blackmagic Media Express works well too.
But, it doesn't work with Aftereffects CC, and premiere pro CC.
What's the problem?
What exact version number of AE are you running (down to the last decimal)?