LiveFFT.py

# -*- coding: utf-8 -*-
"""
Created on May 23 2014

@author: florian
"""
import sys
import threading
import atexit
import pyaudio
import numpy as np
import matplotlib
matplotlib.use("TkAgg")
from matplotlib import figure
from PyQt4 import QtGui, QtCore
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt4agg import NavigationToolbar2QT as NavigationToolbar

# class taken from the SciPy 2015 Vispy talk opening example
# see https://github.com/vispy/vispy/pull/928
class MicrophoneRecorder(object):
    def __init__(self, rate=4000, chunksize=1024):
        self.rate = rate
        self.chunksize = chunksize
        self.p = pyaudio.PyAudio()
        self.stream = self.p.open(format=pyaudio.paInt16,
                                  channels=1,
                                  rate=self.rate,
                                  input=True,
                                  frames_per_buffer=self.chunksize,
                                  stream_callback=self.new_frame)
        self.lock = threading.Lock()
        self.stop = False
        self.frames = []
        atexit.register(self.close)

    def new_frame(self, data, frame_count, time_info, status):
        data = np.fromstring(data, 'int16')
        with self.lock:
            self.frames.append(data)
            if self.stop:
                return None, pyaudio.paComplete
        return None, pyaudio.paContinue

    def get_frames(self):
        with self.lock:
            frames = self.frames
            self.frames = []
            return frames

    def start(self):
        self.stream.start_stream()

    def close(self):
        with self.lock:
            self.stop = True
        self.stream.close()
        self.p.terminate()


class MplFigure(object):
    def __init__(self, parent):
        self.figure = figure.Figure(facecolor='white')
        self.canvas = FigureCanvas(self.figure)
        self.toolbar = NavigationToolbar(self.canvas, parent)

class LiveFFTWidget(QtGui.QWidget):
    def __init__(self):
        QtGui.QWidget.__init__(self)

        # customize the UI
        self.initUI()

        # init class data
        self.initData()

        # connect slots
        self.connectSlots()

        # init MPL widget
        self.initMplWidget()

    def initUI(self):

        hbox_gain = QtGui.QHBoxLayout()
        autoGain = QtGui.QLabel('Auto gain for frequency spectrum')
        autoGainCheckBox = QtGui.QCheckBox(checked=True)
        hbox_gain.addWidget(autoGain)
        hbox_gain.addWidget(autoGainCheckBox)

        # reference to checkbox
        self.autoGainCheckBox = autoGainCheckBox

        hbox_fixedGain = QtGui.QHBoxLayout()
        fixedGain = QtGui.QLabel('Manual gain level for frequency spectrum')
        fixedGainSlider = QtGui.QSlider(QtCore.Qt.Horizontal)
        hbox_fixedGain.addWidget(fixedGain)
        hbox_fixedGain.addWidget(fixedGainSlider)

        self.fixedGainSlider = fixedGainSlider

        vbox = QtGui.QVBoxLayout()

        vbox.addLayout(hbox_gain)
        vbox.addLayout(hbox_fixedGain)

        # mpl figure
        self.main_figure = MplFigure(self)
        vbox.addWidget(self.main_figure.toolbar)
        vbox.addWidget(self.main_figure.canvas)

        self.setLayout(vbox)

        self.setGeometry(300, 300, 350, 300)
        self.setWindowTitle('LiveFFT')
        self.show()
        # timer for calls, taken from:
        # http://ralsina.me/weblog/posts/BB974.html
        timer = QtCore.QTimer()
        timer.timeout.connect(self.handleNewData)
        timer.start(50)
        # keep reference to timer
        self.timer = timer


    def initData(self):
        mic = MicrophoneRecorder()
        mic.start()

        # keeps reference to mic
        self.mic = mic

        # computes the parameters that will be used during plotting
        self.freq_vect = np.fft.rfftfreq(mic.chunksize,
                                         1./mic.rate)
        self.time_vect = np.arange(mic.chunksize, dtype=np.float32) / mic.rate * 1000

    def connectSlots(self):
        pass

    def initMplWidget(self):
        """creates initial matplotlib plots in the main window and keeps
        references for further use"""
        # top plot
        self.ax_top = self.main_figure.figure.add_subplot(211)
        self.ax_top.set_ylim(-32768, 32768)
        self.ax_top.set_xlim(0, self.time_vect.max())
        self.ax_top.set_xlabel(u'time (ms)', fontsize=6)

        # bottom plot
        self.ax_bottom = self.main_figure.figure.add_subplot(212)
        self.ax_bottom.set_ylim(0, 1)
        self.ax_bottom.set_xlim(0, self.freq_vect.max())
        self.ax_bottom.set_xlabel(u'frequency (Hz)', fontsize=6)
        # line objects
        self.line_top, = self.ax_top.plot(self.time_vect,
                                         np.ones_like(self.time_vect))

        self.line_bottom, = self.ax_bottom.plot(self.freq_vect,
                                               np.ones_like(self.freq_vect))


        # tight layout
        #plt.tight_layout()

    def handleNewData(self):
        """ handles the asynchroneously collected sound chunks """
        # gets the latest frames
        frames = self.mic.get_frames()

        if len(frames) > 0:
            # keeps only the last frame
            current_frame = frames[-1]
            # plots the time signal
            self.line_top.set_data(self.time_vect, current_frame)
            # computes and plots the fft signal
            fft_frame = np.fft.rfft(current_frame)
            if self.autoGainCheckBox.checkState() == QtCore.Qt.Checked:
                fft_frame /= np.abs(fft_frame).max()
            else:
                fft_frame *= (1 + self.fixedGainSlider.value()) / 5000000.
                #print(np.abs(fft_frame).max())
            self.line_bottom.set_data(self.freq_vect, np.abs(fft_frame))

            # refreshes the plots
            self.main_figure.canvas.draw()


if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)
    window = LiveFFTWidget()
    sys.exit(app.exec_())