In Vegas version 16 I could set the rendering to Internet 4K UHD 2160p 25 fps (Intel QSV) and was ok, now in version 17 most of the 2160 25 fps don't work any ideas please, Video Camera is Sony AX700 4K. Thanks.
The only one with exact that name is the Magix HEVC codec, in Vpro 17 it is (nearly) exact the same at the same place, name has not "4K" anymore, but UDH and pixelsetting tells you enough.Look