recorder.py

import pyaudio
import wave
import math
import struct

FORMAT = pyaudio.paInt16
CHANNELS = 1
RATE = 44100
CHUNK = 1024
SILENT_THRESHOLD = 0.01
RECORD_SECONDS = 600
WAVE_OUTPUT_FILENAME = "output.wav"

class Recorder:
    def __init__(self):
        self.recording_done_callback = None
                
    def get_rms(self,data):
        count = len(data)/2
        _format = "%dh"%(count)
        shorts = struct.unpack( _format, data )
        sum_squares = 0.0
        for sample in shorts:
            n = sample * (1.0/32768)
            sum_squares += n*n
        return math.sqrt( sum_squares / count )
        
    def record(self):  
        self.audio = pyaudio.PyAudio()              
        stream = self.audio.open(format=FORMAT, channels=CHANNELS,
                            rate=RATE, input=True,
                            frames_per_buffer=CHUNK)

        print("Recording started...")

        frames = []

        silence = 0
        silence_frames = []
        while True:
            data = stream.read(CHUNK)
            frames.append(data)
            rms = self.get_rms(data)
            if rms < SILENT_THRESHOLD:
                silence += 1
                silence_frames.append(data)
            else:
                silence = 0
                silence_frames = []
            if silence > int(RATE / CHUNK * 2):
                break

        print("Recording stopped.")

        stream.stop_stream()
        stream.close()
        self.audio.terminate()

        wf = wave.open(WAVE_OUTPUT_FILENAME, 'wb')
        wf.setnchannels(CHANNELS)
        wf.setsampwidth(self.audio.get_sample_size(FORMAT))
        wf.setframerate(RATE)
        wf.writeframes(b''.join(frames))
        wf.close()
        
        if self.recording_done_callback is not None:
            self.recording_done_callback(WAVE_OUTPUT_FILENAME)