Include some Sipdroid features in my Android Voip application

Include some Sipdroid features in my Android Voip application - I'm writing an Android app and I need to realize VoIP call. - Element of my system are: - Android mobiles - PCs, where I implemented a Java application; here I used some classes coming from opensource project "mjsip"; - target: Android clients has to to comunicate (by VoIP) with PC in half duplex (Android send voice and PC receive voice or viceversa) - I cannot use the native "[login to view URL]", because it is not compatible with the classes on PC. It works, but badly. - I successfully imported Sipdroid code in my Android application (using Android Studio). Job to be done by the developper: 1) Transmit VoIP voice from Android to PC: the developer has to write a Java class (for Android) that gets in input IPaddress and port of receiver PC and (using Sipdroid code) gets the audio from Android microphone, transforms it in VoIP and sends the VoIP stream to the receiver; I need inside the class a method "start_sending" and a method "stop_sending". 2) Receive VoIP voice from PC: the developer has to write a Java class (for Android) that gets in input IPaddress and port of transmitter PC and (using Sipdroid code) receives the VoIP stream from the PC, transforms it in voice and send it to the Android loudspeaker; I need inside the class a method "start_receiving" and a method "stop_receiving". According to my understanding it will be a quick job with few code rows, but the developper in order to do that has to study and understand Sipdroid code. After this basic feature, in the future I'll need other features (using bluetooth, handsfree, duplex call, etc...) Fausto