Audio Source Example¶
A Python application that demonstrates the analogous example in C++ Audio Source Example
# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
from __future__ import annotations
"""
PySide6 port of Qt6 example examples/multimedia/audiosources
Audio Devices demonstrates how to create a simple application to list and test
the configuration for the various audio devices available on the target device
or desktop PC.
Note: This Python example is not fully complete as compared to its C++ counterpart.
Only the push mode works at the moment. For the pull mode to work, the class
QIODevice have python bindings that needs to be fixed.
"""
import os
import sys
import PySide6
from PySide6.QtCore import QByteArray, QMargins, Qt, Slot, qWarning
from PySide6.QtGui import QPainter, QPalette
from PySide6.QtMultimedia import QAudio, QAudioDevice, QAudioFormat, QAudioSource, QMediaDevices
from PySide6.QtWidgets import (QApplication, QComboBox, QPushButton, QSlider, QVBoxLayout,
QWidget, QLabel)
is_android = os.environ.get('ANDROID_ARGUMENT')
if is_android or sys.platform == "darwin":
from PySide6.QtCore import QMicrophonePermission
class AudioInfo:
def __init__(self, format: QAudioFormat):
super().__init__()
self.m_format = format
self.m_level = 0.0
def calculate_level(self, data: bytes, length: int) -> float:
channel_bytes: int = int(self.m_format.bytesPerSample())
sample_bytes: int = int(self.m_format.bytesPerFrame())
num_samples: int = int(length / sample_bytes)
maxValue: float = 0
m_offset: int = 0
for i in range(num_samples):
for j in range(self.m_format.channelCount()):
value = 0
if len(data) > m_offset:
data_sample = data[m_offset:]
value = self.m_format.normalizedSampleValue(data_sample)
maxValue = max(value, maxValue)
m_offset = m_offset + channel_bytes
return maxValue
class RenderArea(QWidget):
def __init__(self, parent: PySide6.QtWidgets.QWidget | None = None) -> None:
super().__init__(parent=parent)
self.m_level = 0
self.setBackgroundRole(QPalette.Base)
self.setAutoFillBackground(True)
self.setMinimumHeight(30)
self.setMinimumWidth(200)
def set_level(self, value):
self.m_level = value
self.update()
def paintEvent(self, event: PySide6.QtGui.QPaintEvent) -> None:
with QPainter(self) as painter:
painter.setPen(Qt.black)
frame = painter.viewport() - QMargins(10, 10, 10, 10)
painter.drawRect(frame)
if self.m_level == 0.0:
return
pos: int = round((frame.width() - 1) * self.m_level)
painter.fillRect(
frame.left() + 1, frame.top() + 1, pos, frame.height() - 1, Qt.red
)
class InputTest(QWidget):
def __init__(self) -> None:
super().__init__()
self.m_devices = QMediaDevices(self)
self.m_pullMode = False
self.initialize()
@Slot()
def initialize(self):
if is_android or sys.platform == "darwin":
is_nuitka = "__compiled__" in globals()
if not is_nuitka and sys.platform == "darwin":
print("This example does not work on macOS when Python is run in interpreted mode."
"For this example to work on macOS, package the example using pyside6-deploy"
"For more information, read `Notes for Developer` in the documentation")
sys.exit(0)
permission = QMicrophonePermission()
permission_status = qApp.checkPermission(permission) # noqa: F821
if permission_status == Qt.PermissionStatus.Undetermined:
qApp.requestPermission(permission, self, self.initialize) # noqa: F821
return
if permission_status == Qt.PermissionStatus.Denied:
qWarning("Microphone permission is not granted!")
self.initializeErrorWindow()
return
elif permission_status == Qt.PermissionStatus.Granted:
print("[AudioSource] Microphone permission granted")
self.initialize_window()
self.initialize_audio(QMediaDevices.defaultAudioInput())
def initialize_window(self):
self.layout = QVBoxLayout(self)
self.m_canvas = RenderArea(self)
self.layout.addWidget(self.m_canvas)
self.m_device_box = QComboBox(self)
default_device_info = QMediaDevices.defaultAudioInput()
self.m_device_box.addItem(
default_device_info.description(), default_device_info
)
for device_info in self.m_devices.audioInputs():
if device_info != default_device_info:
self.m_device_box.addItem(device_info.description(), device_info)
self.m_device_box.activated[int].connect(self.device_changed)
self.layout.addWidget(self.m_device_box)
self.m_volume_slider = QSlider(Qt.Orientation.Horizontal, self)
self.m_volume_slider.setRange(0, 100)
self.m_volume_slider.setValue(100)
self.m_volume_slider.valueChanged.connect(self.slider_changed)
self.layout.addWidget(self.m_volume_slider)
self.m_mode_button = QPushButton(self)
self.m_mode_button.clicked.connect(self.toggle_mode)
self.layout.addWidget(self.m_mode_button)
self.m_suspend_resume_button = QPushButton(self)
self.m_suspend_resume_button.clicked.connect(self.toggle_suspend)
self.layout.addWidget(self.m_suspend_resume_button)
def initializeErrorWindow(self):
self.layout = QVBoxLayout(self)
error_label = QLabel(self.tr("Microphone permission is not granted!"))
error_label.setWordWrap(True)
error_label.setAlignment(Qt.AlignCenter)
self.layout.addWidget(error_label)
def initialize_audio(self, device_info: QAudioDevice):
format = QAudioFormat()
format.setSampleRate(8000)
format.setChannelCount(1)
format.setSampleFormat(QAudioFormat.Int16)
self.m_audio_info = AudioInfo(format)
self.m_audio_input = QAudioSource(device_info, format)
initial_volume = QAudio.convertVolume(
self.m_audio_input.volume(),
QAudio.LinearVolumeScale,
QAudio.LogarithmicVolumeScale,
)
self.m_volume_slider.setValue(int(round(initial_volume * 100)))
self.toggle_mode()
@Slot()
def toggle_mode(self):
self.m_audio_input.stop()
self.toggle_suspend()
self.m_mode_button.setText("Enable pull mode")
io = self.m_audio_input.start()
def push_mode_slot():
len = self.m_audio_input.bytesAvailable()
buffer_size = 4096
if len > buffer_size:
len = buffer_size
buffer: QByteArray = io.read(len)
if len > 0:
level = self.m_audio_info.calculate_level(buffer, len)
self.m_canvas.set_level(level)
io.readyRead.connect(push_mode_slot)
@Slot()
def toggle_suspend(self):
# toggle suspend/resume
state = self.m_audio_input.state()
if (state == QAudio.SuspendedState) or (state == QAudio.StoppedState):
self.m_audio_input.resume()
self.m_suspend_resume_button.setText("Suspend recording")
elif state == QAudio.ActiveState:
self.m_audio_input.suspend()
self.m_suspend_resume_button.setText("Resume recording")
# else no-op
@Slot(int)
def device_changed(self, index):
self.m_audio_input.stop()
self.m_audio_input.disconnect(self)
self.initialize_audio(self.m_device_box.itemData(index))
@Slot(int)
def slider_changed(self, value):
linearVolume = QAudio.convertVolume(
value / float(100), QAudio.LogarithmicVolumeScale, QAudio.LinearVolumeScale
)
self.m_audio_input.setVolume(linearVolume)
if __name__ == "__main__":
app = QApplication(sys.argv)
app.setApplicationName("Audio Sources Example")
input = InputTest()
input.show()
sys.exit(app.exec())