Using an analogue DVR as a video source for VoIP doorphone?

OK... so this might sound horribly convoluted...

I have a 16 camera DVR system, traditional analogue cameras into an IQCCTV 16 Channel DvR which has IP connectivity.

I am looking at the possibility of installing a VoIP phone system to make use of the WiFi network inside the house.

As it's a guest house we run, the idea of a VoIP based door entry system would make a lot of sense.

It's an old property, and a lot of the VoIP camera systems are modern looking and would just spoil the aesthetic of the front door.

A couple of my cameras are door mounted viewers. I was wondering, is there any way that I could take a video stream from the DVR and forward it with VoIP audio to my VoIP phone using some sort of server / software.

I know you can view the IP streams with various apps, but I am wondering if it is possible to interrogate the IP stream in some way as if it were an IP camera.

Failing that... is there some sort of device that would convert an analogue camera input to an IP stream, so I could intercept the analogue signal before the DVR, send it to the DVR but also into a VoIP cmera interface of sorts?

Sorry if it sounds horribly convoluted... just looking for a neat system.

There are IP encoders which would allow you to convert an analog camera to an IP stream, but to be honest this seems like a ton of work and tinkering for something I can but from my supplier for a couple hundred dollars or less if I wait for it to be on sale.