Python record audio on detected sound

The current top answer is a bit outdated and only works for python 2. Here is a version updated for python 3. It wraps the functions into classes and packages everything into one simple easy-to-use version. Note that there is one key difference between the top answer and my script:

The script at the top records for one file and then stops, while my script keeps recording whenever noise is detected and dumps the recordings into a directory as it goes.

The main idea for both scripts are pretty similar:

Step 1: ‘Listen’ until rms becomes greater than the threshold

Step 2: Start recording, set a timer for when to stop recording, == TIMEOUT_LENGTH

Step 3: If the rms breaks threshold again before the timer times out reset the timer

Step 4: Now that the timer is expired, write the recording to a directory and go back to step 1

import pyaudio
import math
import struct
import wave
import time
import os

Threshold = 10

SHORT_NORMALIZE = (1.0/32768.0)
chunk = 1024
FORMAT = pyaudio.paInt16
CHANNELS = 1
RATE = 16000
swidth = 2

TIMEOUT_LENGTH = 5

f_name_directory = r'C:\Users\Jason\PyCharmProjects\AutoRecorder\records'

class Recorder:

    @staticmethod
    def rms(frame):
        count = len(frame) / swidth
        format = "%dh" % (count)
        shorts = struct.unpack(format, frame)

        sum_squares = 0.0
        for sample in shorts:
            n = sample * SHORT_NORMALIZE
            sum_squares += n * n
        rms = math.pow(sum_squares / count, 0.5)

        return rms * 1000

    def __init__(self):
        self.p = pyaudio.PyAudio()
        self.stream = self.p.open(format=FORMAT,
                                  channels=CHANNELS,
                                  rate=RATE,
                                  input=True,
                                  output=True,
                                  frames_per_buffer=chunk)

    def record(self):
        print('Noise detected, recording beginning')
        rec = []
        current = time.time()
        end = time.time() + TIMEOUT_LENGTH

        while current <= end:

            data = self.stream.read(chunk)
            if self.rms(data) >= Threshold: end = time.time() + TIMEOUT_LENGTH

            current = time.time()
            rec.append(data)
        self.write(b''.join(rec))

    def write(self, recording):
        n_files = len(os.listdir(f_name_directory))

        filename = os.path.join(f_name_directory, '{}.wav'.format(n_files))

        wf = wave.open(filename, 'wb')
        wf.setnchannels(CHANNELS)
        wf.setsampwidth(self.p.get_sample_size(FORMAT))
        wf.setframerate(RATE)
        wf.writeframes(recording)
        wf.close()
        print('Written to file: {}'.format(filename))
        print('Returning to listening')



    def listen(self):
        print('Listening beginning')
        while True:
            input = self.stream.read(chunk)
            rms_val = self.rms(input)
            if rms_val > Threshold:
                self.record()

a = Recorder()

a.listen()