‘‘‘ ps_Multimedia_play_sound1.py
explore the PySide QtMultimedia module to play a specified sound
modified PyQT code from:
http://www.diotavelli.net/PyQtWiki/Playing%20a%20sound%20with%20QtMultimedia
PySide is the official LGPL-licensed version of PyQT
for free PySide Windows installers see:
http://developer.qt.nokia.com/wiki/PySide_Binaries_Windows
or
http://www.lfd.uci.edu/~gohlke/pythonlibs/
tested with Python33 and Pyside112 by vegaseat 29jul2013
‘‘‘
from PyQt4.QtCore import *
from PyQt4.QtGui import *
from PyQt4.QtMultimedia import *
from math import pi, sin
import struct
class Window(QWidget):
def __init__(self, parent = None):
QWidget.__init__(self, parent)
# setGeometry(x_pos, y_pos, width, height)
self.setGeometry(300, 300, 400, 80)
self.setWindowTitle("Play a specified sound (2 seconds)")
format = QAudioFormat()
format.setChannels(1)
format.setFrequency(22050)
format.setSampleSize(16)
format.setCodec("audio/pcm")
format.setByteOrder(QAudioFormat.LittleEndian)
format.setSampleType(QAudioFormat.SignedInt)
self.output = QAudioOutput(format, self)
self.frequency = 100
self.volume = 15000
self.buffer = QBuffer()
self.data = QByteArray()
self.pitchSlider = QSlider(Qt.Horizontal)
self.pitchSlider.setMaximum(2000)
self.volumeSlider = QSlider(Qt.Horizontal)
self.volumeSlider.setMaximum(32767)
self.volumeSlider.setPageStep(1024)
self.volumeSlider.setValue(self.volume)
self.playButton = QPushButton("&Play")
self.pitch_label = QLabel()
self.pitchSlider.valueChanged.connect(self.changeFrequency)
self.volumeSlider.valueChanged.connect(self.changeVolume)
self.playButton.clicked.connect(self.play)
# layout managers ...
formLayout = QFormLayout()
formLayout.addRow("P&itch:", self.pitchSlider)
formLayout.addRow("&Volume:", self.volumeSlider)
buttonLayout = QVBoxLayout()
buttonLayout.addWidget(self.pitch_label)
buttonLayout.addWidget(self.playButton)
buttonLayout.addStretch()
horizontalLayout = QHBoxLayout(self)
horizontalLayout.addLayout(formLayout)
horizontalLayout.addLayout(buttonLayout)
self.changeFrequency()
def changeFrequency(self, value=0):
self.frequency = 100 + (value * 2)
s = "pitch = {} Hz".format(self.frequency)
self.pitch_label.setText(s)
def play(self):
if self.output.state() == QAudio.ActiveState:
self.output.stop()
if self.buffer.isOpen():
self.buffer.close()
self.createData()
self.buffer.setData(self.data)
self.buffer.open(QIODevice.ReadOnly)
self.buffer.seek(0)
self.output.start(self.buffer)
def changeVolume(self, value):
self.volume = value
def createData(self):
‘‘‘
create 2 seconds of data with 22050 samples per second,
each sample being 16 bits (2 bytes)
‘‘‘
self.data.clear()
for k in range(2 * 22050):
t = k / 22050.0
value = int(self.volume * sin(2 * pi * self.frequency * t))
self.data.append(struct.pack("<h", value))
# test the module
if __name__ == "__main__":
app = QApplication([])
window = Window()
window.show()
app.exec_()
