make audio semi-optional

beamshow.py

@@ -307,7 +307,7 @@ def app_main() -> None:
         "--audio",
         metavar="NAME",
         type=str,
-        required=True,
+        default="",
         help="The audio device to use. Can be any substring",
     )
     argparser.add_argument(
@@ -357,9 +357,13 @@ def app_main() -> None:
     if args.list_displays:
         print_displays()
 
-    if args.list_displays:
+    if args.list_inputs:
         print_inputs()
 
+    if not args.audio:
+        print("Must select audio input")
+        sys.exit(-1)
+
     show = Beamshow(
         audio_device_name=args.audio,
         render3d=args.render3d,