adjusted demod error handling

modem/demodulator.py

@@ -206,7 +206,7 @@ class Demodulator():
         bytes_per_frame= self.MODE_DICT[mode]["bytes_per_frame"]
         state_buffer = self.MODE_DICT[mode]["state_buffer"]
         mode_name = self.MODE_DICT[mode]["name"]
-
+        try:
             while self.stream.active:
                 threading.Event().wait(0.01)
                 while audiobuffer.nbuffer >= nin:
@@ -249,7 +249,14 @@ class Demodulator():
 
                         self.modem_received_queue.put([bytes_out, freedv, bytes_per_frame, snr])
                         state_buffer = []
-
+        except Exception as e:
+            error_message = str(e)
+            # we expect this error when shutdown
+            if "PortAudio not initialized" in error_message:
+                e = None
+            self.log.debug(
+                "[MDM] [demod_audio] demod loop ended", mode=mode_name, e=e
+            )
     def tci_rx_callback(self) -> None:
         """
         Callback for TCI RX