Following worked for my setup.
Device: NVR4-7000 (Link)
I have managed to find the RTSP option in the menu.
This post helped to figure it out:
For example:
FrontDoor / IP Camera 1
Main Stream: rtsp://admin:[email protected]:554/Streaming/Channels/101
Sub Stream: rtsp://admin:[email protected]:554/Streaming/Channels/102
I had the same problem with Swann NVR8-7400, until an hour ago.
I then read this article NVR-7400 Help · Issue #250 · thirtythreeforty/neolink · GitHub
I now have a Reolink RLN8-410 system 
It took 3 minutes. You will need to use password 12345 to pick up the cameras.
The Reolink integration then effortless imports the cameras to Home Assistant.
I’m very impressed. If you use DDNS on SwannView app, then it’s an easy change…otherwise you can download the Reolink app for your phone.
Good Luck
