check this tutorial to know how to get bytes from recorded audio and how to play it back
https://www.b4x.com/android/forum/t...audio-streaming-over-wifi-or-bluetooth.30648/
this tutorial sends and receive audio PCM data without encoding its HUGE data to transfer over the internet so you need to compress this audio data to be suitable for internet use
use this GSM library to encode and decode (compress) the audio bytes
https://www.b4x.com/android/forum/threads/gsm-library-for-speech-compression.42851
you can do small modification to the walkie-talkie sample above to make it use encoded audio instead of PCM data
to connect to other device over the internet you need a server (you can start with 15$ VPS or less) and you need to write small server app
you can build one using B4j using sockets
this server app will be listening for connection on a specific port and all clients will connect to this port
then the server manage the incoming and outgoing packets
audio recorder > audio encoder > Socket > ||SERVER APP|| > Socket > audio decoder > audio streamer