RTSP or ONVIF bridge to SIP Call?

So crazy idea, I don’t know if this exists but it seems it should be possible. I have a video doorbell that supports both RTSP and ONVIF streams. I would love to find something that can bridge that to a SIP call to my video supported desk phone.

That way when someone presses the doorbell my IP deskphone would ring, I could see the video on the phone, hear them, and they could hear me.

As a bonus the ability to press a button on the phone and have it recognize that tone and trigger an automation in home assistant to unlock my smart lock would really seal the deal for me.

Is anyone aware of anything like this that exists?

So like… a ring doorbell, UniFi doorbell, or insert other smart doorbells here?