in listen_and_play.py [0:0]
def callback_recv(outdata, frames, time, status):
if not recv_queue.empty():
data = recv_queue.get()
outdata[: len(data)] = data
outdata[len(data) :] = b"\x00" * (len(outdata) - len(data))
else:
outdata[:] = b"\x00" * len(outdata)