Audio Example¶
This example shows the drawing of dynamic data (microphone input).
# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
from __future__ import annotations
"""PySide6 port of the charts/audio example from Qt v5.x"""
import sys
from PySide6.QtCharts import QChart, QChartView, QLineSeries, QValueAxis
from PySide6.QtCore import QPointF, Slot
from PySide6.QtMultimedia import QAudioFormat, QAudioSource, QMediaDevices
from PySide6.QtWidgets import QApplication, QMainWindow, QMessageBox
SAMPLE_COUNT = 2000
RESOLUTION = 4
class MainWindow(QMainWindow):
def __init__(self, device):
super().__init__()
self._series = QLineSeries()
self._chart = QChart()
self._chart.addSeries(self._series)
self._axis_x = QValueAxis()
self._axis_x.setRange(0, SAMPLE_COUNT)
self._axis_x.setLabelFormat("%g")
self._axis_x.setTitleText("Samples")
self._axis_y = QValueAxis()
self._axis_y.setRange(-1, 1)
self._axis_y.setTitleText("Audio level")
self._chart.setAxisX(self._axis_x, self._series)
self._chart.setAxisY(self._axis_y, self._series)
self._chart.legend().hide()
name = device.description()
self._chart.setTitle(f"Data from the microphone ({name})")
format_audio = QAudioFormat()
format_audio.setSampleRate(8000)
format_audio.setChannelCount(1)
format_audio.setSampleFormat(QAudioFormat.UInt8)
self._audio_input = QAudioSource(device, format_audio, self)
self._io_device = self._audio_input.start()
self._io_device.readyRead.connect(self._readyRead)
self._chart_view = QChartView(self._chart)
self.setCentralWidget(self._chart_view)
self._buffer = [QPointF(x, 0) for x in range(SAMPLE_COUNT)]
self._series.append(self._buffer)
def closeEvent(self, event):
if self._audio_input is not None:
self._audio_input.stop()
event.accept()
@Slot()
def _readyRead(self):
data = self._io_device.readAll()
available_samples = data.size() // RESOLUTION
start = 0
if (available_samples < SAMPLE_COUNT):
start = SAMPLE_COUNT - available_samples
for s in range(start):
self._buffer[s].setY(self._buffer[s + available_samples].y())
data_index = 0
for s in range(start, SAMPLE_COUNT):
value = (ord(data[data_index]) - 128) / 128
self._buffer[s].setY(value)
data_index = data_index + RESOLUTION
self._series.replace(self._buffer)
if __name__ == '__main__':
app = QApplication(sys.argv)
input_devices = QMediaDevices.audioInputs()
if not input_devices:
QMessageBox.warning(None, "audio", "There is no audio input device available.")
sys.exit(-1)
main_win = MainWindow(input_devices[0])
main_win.setWindowTitle("audio")
available_geometry = main_win.screen().availableGeometry()
size = available_geometry.height() * 3 / 4
main_win.resize(size, size)
main_win.show()
sys.exit(app.exec())