Virtual audio cable between android applications?

Question

Android

Task: to make a conference between a Viber user and a subscriber of a conventional mobile network.

Windows has a virtual audio cable. It can pass the output sound of one application to the input of another.

Is this possible on Android?

Answer 1

I saw something similar a couple of times, they take (or do it themselves) a jack-jack wire (which is not only a sound but also a microphone), then a phone to a phone or a phone to a computer. On one call on a mobile network, on the other (or on a PC) viber \ tg \ vatsap \ whatever.
The collective farm is wild but it worked =D

Answer 2

Applications on official modern buckets have absolutely no access to the audio path of the cellular network (otherwise, it would be possible to implement call recording, which is prohibited).
Therefore, you will not find such joy on a stock phone - you need to look for custom firmware with Linux, and there is an audio jack there.