Merge pull request Kitt-AI#236 from carloalbertobarbano/master

User can call start() again after terminate() in HotwordDetector. Useful for multithreaded applications with exclusive access to the audio input device.

examples/Python3/snowboydecoder.py

@@ -20,7 +20,8 @@
 
 class RingBuffer(object):
     """Ring buffer to hold audio from PortAudio"""
-    def __init__(self, size = 4096):
+
+    def __init__(self, size=4096):
         self._buf = collections.deque(maxlen=size)
 
     def extend(self, data):
@@ -69,16 +70,12 @@ class HotwordDetector(object):
                               default sensitivity in the model will be used.
     :param audio_gain: multiply input volume by this factor.
     """
+
     def __init__(self, decoder_model,
                  resource=RESOURCE_FILE,
                  sensitivity=[],
                  audio_gain=1):
 
-        def audio_callback(in_data, frame_count, time_info, status):
-            self.ring_buffer.extend(in_data)
-            play_data = chr(0) * len(in_data)
-            return play_data, pyaudio.paContinue
-
         tm = type(decoder_model)
         ts = type(sensitivity)
         if tm is not list:
@@ -93,7 +90,7 @@ def audio_callback(in_data, frame_count, time_info, status):
         self.num_hotwords = self.detector.NumHotwords()
 
         if len(decoder_model) > 1 and len(sensitivity) == 1:
-            sensitivity = sensitivity*self.num_hotwords
+            sensitivity = sensitivity * self.num_hotwords
         if len(sensitivity) != 0:
             assert self.num_hotwords == len(sensitivity), \
                 "number of hotwords in decoder_model (%d) and sensitivity " \
@@ -104,16 +101,6 @@ def audio_callback(in_data, frame_count, time_info, status):
 
         self.ring_buffer = RingBuffer(
             self.detector.NumChannels() * self.detector.SampleRate() * 5)
-        self.audio = pyaudio.PyAudio()
-        self.stream_in = self.audio.open(
-            input=True, output=False,
-            format=self.audio.get_format_from_width(
-                self.detector.BitsPerSample() / 8),
-            channels=self.detector.NumChannels(),
-            rate=self.detector.SampleRate(),
-            frames_per_buffer=2048,
-            stream_callback=audio_callback)
-
 
     def start(self, detected_callback=play_audio_file,
               interrupt_check=lambda: False,
@@ -134,6 +121,23 @@ def start(self, detected_callback=play_audio_file,
         :param float sleep_time: how much time in second every loop waits.
         :return: None
         """
+        self._running = True
+
+        def audio_callback(in_data, frame_count, time_info, status):
+            self.ring_buffer.extend(in_data)
+            play_data = chr(0) * len(in_data)
+            return play_data, pyaudio.paContinue
+
+        self.audio = pyaudio.PyAudio()
+        self.stream_in = self.audio.open(
+            input=True, output=False,
+            format=self.audio.get_format_from_width(
+                self.detector.BitsPerSample() / 8),
+            channels=self.detector.NumChannels(),
+            rate=self.detector.SampleRate(),
+            frames_per_buffer=2048,
+            stream_callback=audio_callback)
+
         if interrupt_check():
             logger.debug("detect voice return")
             return
@@ -150,7 +154,7 @@ def start(self, detected_callback=play_audio_file,
 
         logger.debug("detecting...")
 
-        while True:
+        while self._running is True:
             if interrupt_check():
                 logger.debug("detect voice break")
                 break
@@ -167,17 +171,18 @@ def start(self, detected_callback=play_audio_file,
                 message += time.strftime("%Y-%m-%d %H:%M:%S",
                                          time.localtime(time.time()))
                 logger.info(message)
-                callback = detected_callback[ans-1]
+                callback = detected_callback[ans - 1]
                 if callback is not None:
                     callback()
 
         logger.debug("finished.")
 
     def terminate(self):
         """
-        Terminate audio stream. Users cannot call start() again to detect.
+        Terminate audio stream. Users can call start() again to detect.
         :return: None
         """
         self.stream_in.stop_stream()
         self.stream_in.close()
         self.audio.terminate()
+        self._running = False