improve changing streaming modes

src/auracast/server/multicast_frontend.py

@@ -51,14 +51,11 @@ if audio_mode in ["Webapp", "USB"]:
     # Input device selection for USB mode
     if audio_mode == "USB":
         try:
-            import sounddevice as sd  # type: ignore
-            devs = sd.query_devices()
-            log.info('Found audio devices: %s', devs)
-            input_options = [
-                f"{idx}:{d['name']}"
-                for idx, d in enumerate(devs)
-                if d.get('max_input_channels', 0) > 0 and ("(hw:" in d['name'].lower() or "usb" in d['name'].lower())
-            ]
+            resp = requests.get(f"{BACKEND_URL}/audio_inputs", timeout=1)
+            if resp.status_code == 200:
+                input_options = [f"{d['id']}:{d['name']}" for d in resp.json().get('inputs', [])]
+            else:
+                input_options = []
         except Exception:
             input_options = []
 
@@ -75,8 +72,27 @@ if audio_mode in ["Webapp", "USB"]:
     else:
         input_device = None
     start_stream = st.button("Start Auracast")
+    stop_stream = st.button("Stop Auracast")
+
+    if stop_stream:
+        try:
+            r = requests.post(f"{BACKEND_URL}/stop_audio")
+            if r.status_code == 200:
+                st.success("Stream Stopped!")
+            else:
+                st.error(f"Failed to stop: {r.text}")
+        except Exception as e:
+            st.error(f"Error: {e}")
 
     if start_stream:
+        # Always send stop to ensure backend is in a clean state, regardless of current status
+        try:
+            requests.post(f"{BACKEND_URL}/stop_audio", timeout=5)
+        except Exception:
+            # Ignore connection or 500 errors – backend may not be running yet
+            pass
+        # Small pause lets backend fully release audio devices before re-init
+        import time; time.sleep(0.7)
         # Prepare config using the model (do NOT send qos_config, only relevant fields)
         q = quality_map[quality]
         config = auracast_config.AuracastConfigGroup(