Add continuous host mic streaming to real callers

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/main.py

@@ -863,6 +863,29 @@ async def caller_audio_stream(websocket: WebSocket):
             )
 
 
+# --- Host Audio Broadcast ---
+
+async def _broadcast_host_audio(pcm_bytes: bytes):
+    """Send host mic audio to all active real callers"""
+    for caller_id in list(caller_service.active_calls.keys()):
+        try:
+            await caller_service.send_audio_to_caller(caller_id, pcm_bytes, 16000)
+        except Exception:
+            pass
+
+
+def _host_audio_sync_callback(pcm_bytes: bytes):
+    """Sync wrapper to schedule async broadcast from audio thread"""
+    try:
+        loop = asyncio.get_event_loop()
+        if loop.is_running():
+            loop.call_soon_threadsafe(
+                asyncio.ensure_future, _broadcast_host_audio(pcm_bytes)
+            )
+    except Exception:
+        pass
+
+
 # --- Queue Endpoints ---
 
 @app.get("/api/queue")
@@ -888,6 +911,10 @@ async def take_call_from_queue(caller_id: str):
     # Notify caller they're on air via WebSocket
     await caller_service.notify_caller(caller_id, {"status": "on_air", "channel": call_info["channel"]})
 
+    # Start host mic streaming if this is the first real caller
+    if len(caller_service.active_calls) == 1:
+        audio_service.start_host_stream(_host_audio_sync_callback)
+
     return {
         "status": "on_air",
         "caller": call_info,
@@ -1009,6 +1036,10 @@ async def hangup_real_caller():
     caller_service.hangup(caller_id)
     await caller_service.disconnect_caller(caller_id)
 
+    # Stop host streaming if no more active callers
+    if len(caller_service.active_calls) == 0:
+        audio_service.stop_host_stream()
+
     session.active_real_caller = None
 
     # Play hangup sound

backend/services/audio.py

@@ -48,6 +48,10 @@ class AudioService:
         self._caller_stop_event = threading.Event()
         self._caller_thread: Optional[threading.Thread] = None
 
+        # Host mic streaming state
+        self._host_stream: Optional[sd.InputStream] = None
+        self._host_send_callback: Optional[Callable] = None
+
         # Sample rates
         self.input_sample_rate = 16000  # For Whisper
         self.output_sample_rate = 24000  # For TTS
@@ -345,6 +349,55 @@ class AudioService:
         except Exception as e:
             print(f"Real caller audio routing error: {e}")
 
+    # --- Host Mic Streaming ---
+
+    def start_host_stream(self, send_callback: Callable):
+        """Start continuous host mic capture for streaming to real callers"""
+        if self.input_device is None:
+            print("[Audio] No input device configured for host streaming")
+            return
+
+        self._host_send_callback = send_callback
+
+        device_info = sd.query_devices(self.input_device)
+        max_channels = device_info['max_input_channels']
+        device_sr = int(device_info['default_samplerate'])
+        record_channel = min(self.input_channel, max_channels) - 1
+
+        import librosa
+
+        def callback(indata, frames, time_info, status):
+            if not self._host_send_callback:
+                return
+            # Extract the configured input channel
+            mono = indata[:, record_channel].copy()
+            # Resample to 16kHz if needed
+            if device_sr != 16000:
+                mono = librosa.resample(mono, orig_sr=device_sr, target_sr=16000)
+            # Convert float32 to int16 PCM
+            pcm = (mono * 32767).astype(np.int16).tobytes()
+            self._host_send_callback(pcm)
+
+        self._host_stream = sd.InputStream(
+            device=self.input_device,
+            channels=max_channels,
+            samplerate=device_sr,
+            dtype=np.float32,
+            blocksize=4096,
+            callback=callback,
+        )
+        self._host_stream.start()
+        print(f"[Audio] Host mic streaming started (device {self.input_device} ch {self.input_channel} @ {device_sr}Hz)")
+
+    def stop_host_stream(self):
+        """Stop host mic streaming"""
+        if self._host_stream:
+            self._host_stream.stop()
+            self._host_stream.close()
+            self._host_stream = None
+            self._host_send_callback = None
+            print("[Audio] Host mic streaming stopped")
+
     # --- Music Playback ---
 
     def load_music(self, file_path: str) -> bool: