mic.py 文件源码

def fetch_threshold(self):

        # TODO: Consolidate variables from the next three functions
        THRESHOLD_MULTIPLIER = 1.8
        RATE = 16000
        CHUNK = 1024

        # number of seconds to allow to establish threshold
        THRESHOLD_TIME = 1

        # prepare recording stream
        stream = self._audio.open(format=pyaudio.paInt16,
                                  channels=1,
                                  rate=RATE,
                                  input=True,
                                  frames_per_buffer=CHUNK)

        # stores the audio data
        frames = []

        # stores the lastN score values
        lastN = [i for i in range(20)]

        # calculate the long run average, and thereby the proper threshold
        for i in range(0, RATE / CHUNK * THRESHOLD_TIME):

            data = stream.read(CHUNK)
            frames.append(data)

            # save this data point as a score
            lastN.pop(0)
            lastN.append(self.get_score(data))
            average = sum(lastN) / len(lastN)

        stream.stop_stream()
        stream.close()

        # this will be the benchmark to cause a disturbance over!
        THRESHOLD = average * THRESHOLD_MULTIPLIER

        return THRESHOLD