用python写一边录音一边播放一边显示FFT波形pyqt5多线程的程序

由于录音和播放都需要使用麦克风和扬声器，所以需要使用PyAudio库来实现。同时，为了实现多线程，需要使用QtCore模块中的QThread类。

以下是一个简单的示例程序，能够同时进行录音、播放和显示FFT波形：

import sys
import numpy as np
import pyaudio
import wave
from PyQt5 import QtWidgets, QtCore
from matplotlib.backends.qt_compat import QtWidgets as MplWidget
from matplotlib.figure import Figure

CHUNK = 1024
FORMAT = pyaudio.paInt16
CHANNELS = 1
RATE = 44100
WAVE_OUTPUT_FILENAME = "output.wav"

class RecorderThread(QtCore.QThread):
    def __init__(self):
        super().__init__()
        self.frames = []
        self.p = pyaudio.PyAudio()
        self.stream = self.p.open(format=FORMAT,
                                  channels=CHANNELS,
                                  rate=RATE,
                                  input=True,
                                  frames_per_buffer=CHUNK)
        
    def run(self):
        while True:
            data = self.stream.read(CHUNK)
            self.frames.append(data)
            
    def stop(self):
        self.stream.stop_stream()
        self.stream.close()
        self.p.terminate()

class PlayerThread(QtCore.QThread):
    def __init__(self):
        super().__init__()
        self.p = pyaudio.PyAudio()
        self.stream = self.p.open(format=FORMAT,
                                  channels=CHANNELS,
                                  rate=RATE,
                                  output=True,
                                  frames_per_buffer=CHUNK)
        
    def run(self):
        while True:
            if len(recorder_thread.frames) > 0:
                data = recorder_thread.frames.pop(0)
                self.stream.write(data)
            
    def stop(self):
        self.stream.stop_stream()
        self.stream.close()
        self.p.terminate()

class FFTPlotWidget(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()
        self.figure = Figure()
        self.canvas = MplWidget(self.figure)
        layout = QtWidgets.QVBoxLayout()
        layout.addWidget(self.canvas)
        self.setLayout(layout)
        self.ax = self.figure.add_subplot(111)
        self.ax.set_xlim(0, RATE/2)
        self.ax.set_ylim(0, 100)
        self.ax.set_xlabel('Frequency (Hz)')
        self.ax.set_ylabel('Amplitude')
        self.line, = self.ax.plot([], [])

    def update(self):
        if len(recorder_thread.frames) > 0:
            data = b''.join(recorder_thread.frames)
            y = np.frombuffer(data, dtype=np.int16)
            yf = np.fft.rfft(y)
            xf = np.linspace(0, RATE/2, len(yf))
            self.line.set_data(xf, np.abs(yf))
            self.canvas.draw()

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()
        self.recording = False
        self.playing = False
        self.recorder_thread = RecorderThread()
        self.player_thread = PlayerThread()
        self.fft_plot_widget = FFTPlotWidget()
        self.setCentralWidget(self.fft_plot_widget)
        self.start_button = QtWidgets.QPushButton('Start')
        self.start_button.clicked.connect(self.start_recording)
        self.stop_button = QtWidgets.QPushButton('Stop')
        self.stop_button.clicked.connect(self.stop_recording)
        self.toolbar = self.addToolBar('Toolbar')
        self.toolbar.addWidget(self.start_button)
        self.toolbar.addWidget(self.stop_button)
        self.show()

    def start_recording(self):
        self.recording = True
        self.playing = True
        self.recorder_thread.start()
        self.player_thread.start()

    def stop_recording(self):
        self.recording = False
        self.playing = False
        self.recorder_thread.stop()
        self.player_thread.stop()

    def update_fft_plot(self):
        self.fft_plot_widget.update()

app = QtWidgets.QApplication(sys.argv)
main_window = MainWindow()
timer = QtCore.QTimer()
timer.timeout.connect(main_window.update_fft_plot)
timer.start(50)
sys.exit(app.exec_())

该程序使用了三个线程，分别用于录音、播放和更新FFT波形图。其中，录音和播放线程都是无限循环，不断从麦克风读取音频数据和向扬声器写入音频数据。更新FFT波形图的线程使用了Qt的定时器，每隔一定时间就更新一次FFT波形图。

FFT波形图的显示使用了matplotlib库。在FFTPlotWidget类中，定义了一个Figure对象和一个Axes对象，用于绘制FFT波形图。update方法会在每次定时器触发时被调用，从录音线程中获取音频数据，计算FFT并更新图形。

程序界面中只有两个按钮，分别用于开始录音和停止录音。通过点击这两个按钮可以控制录音的开始和结束。在录音过程中，程序会自动播放录制的音频数据，并且实时地显示FFT波形图。