It adds to the nvr using onvif protocol.
Some to add as I have done the same.
The only problem is you lose some functionality nvr side for the ptz as it's a mix and match and uses onvif
My situation it doesn't overly matter too much as I just record 24/7 on the nvr and use it for viewing/playback.
I did try to get the nvr to take a motion event from a fixed hikvision cam and activate a preset on the dahua ptz but it doesn't work and doesn't allow you to select the ptz as a ptz properly to be able to do it.
You still get the ptz functionality through the nvr but anything else is limited and must be confirmed directly on the camera
