PySide2 and PySide6 freezes when a QThread contains a PyAudio() stream, while PyQt5 works well. Is that a bug or I had the wrong usage?

Haujet Zhao

When using PySide2 or PySide6, opening a PyAudio stream in a QThread, many actions relating to GUI and webbrowser will result the GUI freezing.

But Using PyQt5 with the same code won't meet any trouble. I wonder is this a bug of PySide?

I'm running it on Windows10, using PySide2(5.15.0), PySide6(6.0.0), PyQt5(5.15.0).

Here is the code:

import sys, pyaudio
from PySide2.QtCore import *
from PySide2.QtWidgets import *
from PySide2.QtGui import *
import threading, webbrowser

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        widget = Widget()
        self.setCentralWidget(widget)
        self.show()

class Widget(QWidget):
    def __init__(self):
        super().__init__()
        self.btn1 = QPushButton('''Open Being''')
        self.btn1.clicked.connect(lambda: webbrowser.open('https://www.bing.com'))
        self.btn2 = QPushButton('''Get pyaudio''')
        self.btn2.clicked.connect(self.getPyaudioThread)
        layout = QVBoxLayout()
        layout.addWidget(self.btn1)
        layout.addWidget(self.btn2)
        self.setLayout(layout)

    def getPyaudioThread(self):
        self.pyaudioThread = PyaudioThread()
        self.pyaudioThread.start()

class PyaudioThread(QThread):
    CHUNK = 1024
    FORMAT = pyaudio.paInt16
    CHANNELS = 1
    RATE = 16000

    def __init__(self):
        super().__init__()

    def record(self, stream):
        while True:
            stream.read(self.CHUNK)

    def run(self):
        p = pyaudio.PyAudio()
        stream = p.open(channels=self.CHANNELS,
                        format=self.FORMAT,
                        rate=self.RATE,
                        input=True,
                        frames_per_buffer=self.CHUNK)
        # threading.Thread(target=self.record, args=[stream]).start()
        print('pyaudio required')

def main():
    app = QApplication(sys.argv)
    mainWindow = MainWindow()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()

After running it, first click "Get pyaudio" button, then click "Open Being" button, then the whole GUI will freeze.

Replacing the PySide2 to PySide6 also have the same problem, but replaceing the PySide2 to PyQt5 will run normally.

Is this a bug or I had the wrong usage?

JonB

@Haujet-Zhao
I don't know whether it's "supposed" to work in PySide. PyQt5 is more robust/has more support for other libraries. Have a read anyway of the (only) reply to https://stackoverflow.com/questions/63502837/pyqt5-app-using-timer-to-run-a-function-with-a-loop-makes-it-freeze-up, as possible way forward for PySide2/6?