I believe with the Denon's (and other receivers) that there can be video loss because the On-Screen menus, such as 'volue level' can be shown as you use them. But, I'm pretty sure that there are options to disable such on screen menus, likewise, I believe that the OSDs just are introduced into the video stream when necessary.
So, if you aren't introducing any additional digital information, and you aren't processing anything going through the HDMI input, which IS an option on the Denon, then you are passing a 100% unprocessed signal through the machine, in digital format, with next to zero chance of signal degradation in a well built piece of gear.
Denon, at the very least, is known for having well built pieces of gear.