VAD fallback (#97)

* Silero VAD preferred with webrtc fallback

* webrtc VAD neds a different sample size

* fixup

* fixup

src/dailyai/transports/daily_transport.py

@@ -5,6 +5,7 @@
 import threading
 import types
 
+from enum import Enum
 from functools import partial
 from typing import Any
 
@@ -33,6 +34,11 @@
 
 from dailyai.transports.threaded_transport import ThreadedTransport
 
+NUM_CHANNELS = 1
+
+SPEECH_THRESHOLD = 0.90
+VAD_RESET_PERIOD_MS = 2000
+
 
 class DailyTransport(ThreadedTransport, EventHandler):
     _daily_initialized = False
@@ -55,6 +61,7 @@ def __init__(
         start_transcription: bool = False,
         **kwargs,
     ):
+        kwargs['has_webrtc_vad'] = True
         # This will call ThreadedTransport.__init__ method, not EventHandler
         super().__init__(**kwargs)
 
@@ -86,6 +93,12 @@ def __init__(
 
         self._event_handlers = {}
 
+        self.webrtc_vad = Daily.create_native_vad(
+            reset_period_ms=VAD_RESET_PERIOD_MS,
+            sample_rate=self._speaker_sample_rate,
+            channels=NUM_CHANNELS
+        )
+
     def _patch_method(self, event_name, *args, **kwargs):
         try:
             for handler in self._event_handlers[event_name]:
@@ -106,6 +119,18 @@ def _patch_method(self, event_name, *args, **kwargs):
             self._logger.error(f"Exception in event handler {event_name}: {e}")
             raise e
 
+    def _webrtc_vad_analyze(self):
+        buffer = self.read_audio_frames(
+            int(self._vad_samples))
+        if len(buffer) > 0:
+            confidence = self.webrtc_vad.analyze_frames(buffer)
+            # yeses = int(confidence * 20.0)
+            # nos = 20 - yeses
+            # out = "!" * yeses + "." * nos
+            # print(f"!!! confidence: {out} {confidence}")
+            talking = confidence > SPEECH_THRESHOLD
+            return talking
+
     def add_event_handler(self, event_name: str, handler):
         if not event_name.startswith("on_"):
             raise Exception(

src/dailyai/transports/threaded_transport.py

@@ -40,9 +40,6 @@ def int2float(sound):
     return sound
 
 
-SAMPLE_RATE = 16000
-
-
 class VADState(Enum):
     QUIET = 1
     STARTING = 2
@@ -61,11 +58,12 @@ def __init__(
         self._vad_stop_s = kwargs.get("vad_stop_s") or 0.8
         self._context = kwargs.get("context") or []
         self._vad_enabled = kwargs.get("vad_enabled") or False
-
+        self._has_webrtc_vad = kwargs.get("has_webrtc_vad") or False
         if self._vad_enabled and self._speaker_enabled:
             raise Exception(
                 "Sorry, you can't use speaker_enabled and vad_enabled at the same time. Please set one to False."
             )
+        self._vad_samples = 1536
 
         if self._vad_enabled:
             try:
@@ -79,14 +77,19 @@ def __init__(
                 (self.model, self.utils) = torch.hub.load(
                     repo_or_dir="snakers4/silero-vad", model="silero_vad", force_reload=False
                 )
+                self._logger.debug("Loaded Silero VAD")
 
             except ModuleNotFoundError as e:
-                print(f"Exception: {e}")
-                print("In order to use VAD, you'll need to install the `torch` and `torchaudio` modules.")
-                raise Exception(f"Missing module(s): {e}")
+                if self._has_webrtc_vad:
+                    self._logger.debug(f"Couldn't load torch; using webrtc VAD")
+                    self._vad_samples = int(self._speaker_sample_rate / 100.0)
+                else:
+                    self._logger.error(f"Exception: {e}")
+                    self._logger.error(
+                        "In order to use VAD, you'll need to install the `torch` and `torchaudio` modules.")
+                    raise Exception(f"Missing module(s): {e}")
 
-        self._vad_samples = 1536
-        vad_frame_s = self._vad_samples / SAMPLE_RATE
+        vad_frame_s = self._vad_samples / self._speaker_sample_rate
         self._vad_start_frames = round(self._vad_start_s / vad_frame_s)
         self._vad_stop_frames = round(self._vad_stop_s / vad_frame_s)
         self._vad_starting_count = 0
@@ -262,19 +265,28 @@ def read_audio_frames(self, desired_frame_count):
     def _prerun(self):
         pass
 
+    def _silero_vad_analyze(self):
+        audio_chunk = self.read_audio_frames(self._vad_samples)
+        audio_int16 = np.frombuffer(audio_chunk, np.int16)
+        audio_float32 = int2float(audio_int16)
+        new_confidence = self.model(
+            torch.from_numpy(audio_float32), 16000).item()
+        # yeses = int(new_confidence * 20.0)
+        # nos = 20 - yeses
+        # out = "!" * yeses + "." * nos
+        # print(f"!!! confidence: {out}")
+        speaking = new_confidence > 0.5
+        return speaking
+
     def _vad(self):
-        # CB: Starting silero VAD stuff
-        # TODO-CB: Probably need to force virtual speaker creation if we're
-        # going to build this in?
-        # TODO-CB: pyaudio installation
-        while not self._stop_threads.is_set():
-            audio_chunk = self.read_audio_frames(self._vad_samples)
-            audio_int16 = np.frombuffer(audio_chunk, np.int16)
-            audio_float32 = int2float(audio_int16)
-            new_confidence = self.model(
-                torch.from_numpy(audio_float32), 16000).item()
-            speaking = new_confidence > 0.5
 
+        while not self._stop_threads.is_set():
+            if hasattr(self, 'model'):  # we can use Silero
+                speaking = self._silero_vad_analyze()
+            elif self._has_webrtc_vad:
+                speaking = self._webrtc_vad_analyze()
+            else:
+                raise Exception("VAD is running with no VAD service available")
             if speaking:
                 match self._vad_state:
                     case VADState.QUIET:
@@ -311,6 +323,7 @@ def _vad(self):
                 self._vad_state == VADState.STOPPING
                 and self._vad_stopping_count >= self._vad_stop_frames
             ):
+
                 if self._loop:
                     asyncio.run_coroutine_threadsafe(
                         self.receive_queue.put(