I am trying to implement a scenario whereby App-User A can make a voice (video not so important now) call to App-User B on Android. It seems difficult to come across a good tutorial that covers the whole picture. However, from my research, I have been able to learn couple of things but still not enough to get it done.
From what I learnt so far, to implement App-to-App calling, one can either user SIP or WebRTC. PJSIP seems to be fairly popular. After much effort, I was able to build the pjsip project and also run the sample pjsua2 app on my android device but got stuck in Account Settings section of the sample app as I don't know how to come about the credentials it's requesting for (ID, Registrar, Proxy, Username and Password). Also, I can't seem to get a decent tutorial on learning how to use the pjsip libraries.
I also spent some time looking into WebRTC, which kind of looks simpler than pjsip using jingle, but where I got stuck is getting useful resource or tutorials on how to setup a signalling server and some other required stuffs like STUN, TURN, etc.
Though, I am still battling in thoughts with which (PJSIP or WebRTC using Jingle) will deliver the best experience in terms of voice/sound quality and bandwidth friendliness, but at least I just want to get one up and running without issues.
During my search, I came across Sinch API, which does exactly what I want, but for some reasons, we have been told not to use it.
I will very much appreciate a point in the right direction and links to learning resources as well.
