feat: add gain control for USB and webapp microphone inputs with persistence - to be tested

src/auracast/server/multicast_frontend.py

@@ -14,14 +14,27 @@ PTIME = 40
 BACKEND_URL = "http://localhost:5000"
 
 # Try loading persisted settings from backend
+# This is the correct place to define saved_settings before it's used for defaults
 saved_settings = {}
 try:
     resp = requests.get(f"{BACKEND_URL}/status", timeout=1)
     if resp.status_code == 200:
         saved_settings = resp.json()
 except Exception:
+    # If backend is not available or error, saved_settings will be empty dict
+    # Defaults will be used for gain values in this case.
     saved_settings = {}
 
+# Initialize gain session states
+# This must come AFTER saved_settings is populated.
+default_webapp_gain = float(saved_settings.get('webapp_mic_gain', 1.0))
+if 'webapp_mic_gain' not in st.session_state:
+    st.session_state.webapp_mic_gain = default_webapp_gain
+
+default_usb_gain = float(saved_settings.get('usb_mic_gain', 1.0))
+if 'usb_mic_gain' not in st.session_state:
+    st.session_state.usb_mic_gain = default_usb_gain
+
 st.title("🎙️ Auracast Audio Mode Control")
 
 # Audio mode selection with persisted default
@@ -53,9 +66,12 @@ if audio_mode in ["Webapp", "USB"]:
     language = st.text_input("Language (ISO 639-3)", value=default_lang)
     # Gain slider for Webapp mode
     if audio_mode == "Webapp":
-        mic_gain = st.slider("Microphone Gain", 0.0, 4.0, 1.0, 0.1, help="Adjust microphone volume sent to Auracast")
-    else:
-        mic_gain = 1.0
+        st.session_state.webapp_mic_gain = st.slider(
+            "Microphone Gain", 0.0, 4.0, st.session_state.webapp_mic_gain, 0.1,
+            help="Adjust microphone volume sent to Auracast (applied by browser)"
+        )
+    # For USB mode, gain slider is defined below.
+    # The variable 'mic_gain' for JS is sourced from st.session_state.webapp_mic_gain within Webapp mode logic.
 
     # Input device selection for USB mode
     if audio_mode == "USB":
@@ -87,6 +103,16 @@ if audio_mode in ["Webapp", "USB"]:
                 st.rerun()
         # We send only the numeric/card identifier (before :) or 'default'
         input_device = selected_option.split(":", 1)[0] if ":" in selected_option else selected_option
+
+        # USB Microphone Gain Slider
+        st.session_state.usb_mic_gain = st.slider(
+            "Microphone Gain (USB)",
+            min_value=0.0,
+            max_value=4.0,
+            value=st.session_state.usb_mic_gain, # Use session state value
+            step=0.1,
+            help="Adjust microphone volume for USB input (applied by server)"
+        )
     else:
         input_device = None
     start_stream = st.button("Start Auracast")
@@ -96,7 +122,7 @@ if audio_mode in ["Webapp", "USB"]:
     if audio_mode == "Webapp" and st.session_state.get('stream_started'):
         update_js = f"""
         <script>
-            if (window.gainNode) {{ window.gainNode.gain.value = {mic_gain}; }}
+            if (window.gainNode) {{ window.gainNode.gain.value = {st.session_state.webapp_mic_gain}; }}
         </script>
         """
         st.components.v1.html(update_js, height=0)
@@ -122,6 +148,17 @@ if audio_mode in ["Webapp", "USB"]:
         import time; time.sleep(1)
         # Prepare config using the model (do NOT send qos_config, only relevant fields)
         q = quality_map[quality]
+
+        # Determine audio_source based on mode and gain settings
+        if audio_mode == "USB":
+            current_usb_gain = st.session_state.get('usb_mic_gain', 1.0) # Use .get for safety
+            audio_source_str = f"device:{input_device},gain={current_usb_gain}"
+        elif audio_mode == "Webapp":
+            audio_source_str = "webrtc"
+            # Webapp gain is handled client-side by JS using st.session_state.webapp_mic_gain
+        else: # Assuming a 'network' mode or other future modes
+            audio_source_str = "network" # Default or handle other modes
+
         config = auracast_config.AuracastConfigGroup(
             auracast_sampling_rate_hz=q['rate'],
             octets_per_frame=q['octets'],
@@ -131,11 +168,7 @@ if audio_mode in ["Webapp", "USB"]:
                     name=stream_name,
                     program_info=f"{stream_name} {quality}",
                     language=language,
-                    audio_source=(
-                        f"device:{input_device}" if audio_mode == "USB" else (
-                            "webrtc" if audio_mode == "Webapp" else "network"
-                        )
-                    ),
+                    audio_source=audio_source_str, # Use the constructed string
                     input_format=(f"int16le,{q['rate']},1" if audio_mode == "USB" else "auto"),
                     iso_que_len=1, # TODO: this should be way less to decrease delay
                     sampling_frequency=q['rate'],
@@ -160,7 +193,7 @@ if audio_mode in ["Webapp", "USB"]:
             (async () => {{
                 if (window.webrtc_started) return; // Prevent re-init on rerun
                 window.webrtc_started = true;
-                const GAIN_VALUE = {mic_gain};
+                const GAIN_VALUE = {st.session_state.webapp_mic_gain};
                 const pc = new RTCPeerConnection(); // No STUN needed for localhost
                 const micStream = await navigator.mediaDevices.getUserMedia({{audio:true}});
                 // Create Web Audio gain processing