Calls between site users?

Question

VoIP

Good day, you need to implement calls between users through the site. Tell me a few ideas)
Explanation: the user enters the page to another user, presses the call button. Another user in his browser sees a pop-up window like user X is calling you, and a couple of Accept or Decline buttons.

Answer 1

habrahabr.ru/post/198632

Answer 2

If you explain on your fingers how WebRTC calls work, then it looks like this:
1. Sasha and Kuzya opened the page in the browser. On the JavaScript page.
They are naturally not at the same computer, but most likely in different cities.
2. Next, they must exchange codecs and give each other their WebRTC coordinates (IP addresses and ports). For example, if Sasha has Google Chrome, then the VP8 video codec will be a priority, and if Firefox, then H.264, as far as I remember.
3. After they have exchanged this information, the traffic starts to go from one to another (perhaps through the TURN server) and we have an established call.
The exchange of the necessary information is called "signaling" and requires a third-party server. Nothing without him. The participants in the call will not know each other's IP address unless there is a central server that will help them with this.
Well, there are many more options.
Select the desired server or cloud service and call through it.
Here are two examples of establishing a connection through the Flashphoner server:
1. Signaling goes through SIP.
www.youtube.com/watch?v=BG7CZSsR8WA
2. Simple streaming. One gives the flow, the other plays and vice versa.
www.youtube.com/watch?v=0eBm5rL6nSs