I am trying to duplicate my Line In over USB Sound Card.
I have RPi 3 B+ and USB Sound Card with Line In.
Currently I have an application for stream over IP the Line In audio of USB sound card. Now I want to make a VU meter to observ sound level of input. I tried to use arecord or sox but I am getting source is busy error because my application uses the ALSA audio source. How can I duplicate it? Maybe create a virtual piped audio in that can alsa recognize ? Or another approach for it