#!/usr/bin/env python
#############################################################################
##
## Copyright (C) 2013 Riverbank Computing Limited.
## Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
## All rights reserved.
##
## This file is part of the examples of PyQt.
##
## $QT_BEGIN_LICENSE:BSD$
## You may use this file under the terms of the BSD license as follows:
##
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## modification, are permitted provided that the following conditions are
## met:
## * Redistributions of source code must retain the above copyright
## notice, this list of conditions and the following disclaimer.
## * Redistributions in binary form must reproduce the above copyright
## notice, this list of conditions and the following disclaimer in
## the documentation and/or other materials provided with the
## distribution.
## * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
## the names of its contributors may be used to endorse or promote
## products derived from this software without specific prior written
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## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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## $QT_END_LICENSE$
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#############################################################################
from math import pi, sin
from struct import pack
from PyQt5.QtCore import QByteArray, QIODevice, Qt, QTimer, qWarning
from PyQt5.QtMultimedia import (QAudio, QAudioDeviceInfo, QAudioFormat,
QAudioOutput)
from PyQt5.QtWidgets import (QApplication, QComboBox, QHBoxLayout, QLabel,
QMainWindow, QPushButton, QSlider, QVBoxLayout, QWidget)
class Generator(QIODevice):
def __init__(self, format, durationUs, sampleRate, parent):
super(Generator, self).__init__(parent)
self.m_pos = 0
self.m_buffer = QByteArray()
self.generateData(format, durationUs, sampleRate)
def start(self):
self.open(QIODevice.ReadOnly)
def stop(self):
self.m_pos = 0
self.close()
def generateData(self, format, durationUs, sampleRate):
pack_format = ''
if format.sampleSize() == 8:
if format.sampleType() == QAudioFormat.UnSignedInt:
scaler = lambda x: ((1.0 + x) / 2 * 255)
pack_format = 'B'
elif format.sampleType() == QAudioFormat.SignedInt:
scaler = lambda x: x * 127
pack_format = 'b'
elif format.sampleSize() == 16:
if format.sampleType() == QAudioFormat.UnSignedInt:
scaler = lambda x: (1.0 + x) / 2 * 65535
pack_format = '<H' if format.byteOrder() == QAudioFormat.LittleEndian else '>H'
elif format.sampleType() == QAudioFormat.SignedInt:
scaler = lambda x: x * 32767
pack_format = '<h' if format.byteOrder() == QAudioFormat.LittleEndian else '>h'
assert(pack_format != '')
channelBytes = format.sampleSize() // 8
sampleBytes = format.channelCount() * channelBytes
length = (format.sampleRate() * format.channelCount() * (format.sampleSize() // 8)) * durationUs // 100000
self.m_buffer.clear()
sampleIndex = 0
factor = 2 * pi * sampleRate / format.sampleRate()
while length != 0:
x = sin((sampleIndex % format.sampleRate()) * factor)
packed = pack(pack_format, int(scaler(x)))
for _ in range(format.channelCount()):
self.m_buffer.append(packed)
length -= channelBytes
sampleIndex += 1
def readData(self, maxlen):
data = QByteArray()
total = 0
while maxlen > total:
chunk = min(self.m_buffer.size() - self.m_pos, maxlen - total)
data.append(self.m_buffer.mid(self.m_pos, chunk))
self.m_pos = (self.m_pos + chunk) % self.m_buffer.size()
total += chunk
return data.data()
def writeData(self, data):
return 0
def bytesAvailable(self):
return self.m_buffer.size() + super(Generator, self).bytesAvailable()
class AudioTest(QMainWindow):
PUSH_MODE_LABEL = "Enable push mode"
PULL_MODE_LABEL = "Enable pull mode"
SUSPEND_LABEL = "Suspend playback"
RESUME_LABEL = "Resume playback"
DurationSeconds = 1
ToneSampleRateHz = 600
DataSampleRateHz = 44100
def __init__(self):
super(AudioTest, self).__init__()
self.m_device = QAudioDeviceInfo.defaultOutputDevice()
self.m_output = None
self.initializeWindow()
self.initializeAudio()
def initializeWindow(self):
layout = QVBoxLayout()
self.m_deviceBox = QComboBox(activated=self.deviceChanged)
for deviceInfo in QAudioDeviceInfo.availableDevices(QAudio.AudioOutput):
self.m_deviceBox.addItem(deviceInfo.deviceName(), deviceInfo)
layout.addWidget(self.m_deviceBox)
self.m_modeButton = QPushButton(clicked=self.toggleMode)
self.m_modeButton.setText(self.PUSH_MODE_LABEL)
layout.addWidget(self.m_modeButton)
self.m_suspendResumeButton = QPushButton(
clicked=self.toggleSuspendResume)
self.m_suspendResumeButton.setText(self.SUSPEND_LABEL)
layout.addWidget(self.m_suspendResumeButton)
volumeBox = QHBoxLayout()
volumeLabel = QLabel("Volume:")
self.m_volumeSlider = QSlider(Qt.Horizontal, minimum=0, maximum=100,
singleStep=10, valueChanged=self.volumeChanged)
volumeBox.addWidget(volumeLabel)
volumeBox.addWidget(self.m_volumeSlider)
layout.addLayout(volumeBox)
window = QWidget()
window.setLayout(layout)
self.setCentralWidget(window)
def initializeAudio(self):
self.m_pullTimer = QTimer(self, timeout=self.pullTimerExpired)
self.m_pullMode = True
self.m_format = QAudioFormat()
self.m_format.setSampleRate(self.DataSampleRateHz)
self.m_format.setChannelCount(1)
self.m_format.setSampleSize(16)
self.m_format.setCodec('audio/pcm')
self.m_format.setByteOrder(QAudioFormat.LittleEndian)
self.m_format.setSampleType(QAudioFormat.SignedInt)
info = QAudioDeviceInfo(QAudioDeviceInfo.defaultOutputDevice())
if not info.isFormatSupported(self.m_format):
qWarning("Default format not supported - trying to use nearest")
self.m_format = info.nearestFormat(self.m_format)
self.m_generator = Generator(self.m_format,
self.DurationSeconds * 1000000, self.ToneSampleRateHz, self)
self.createAudioOutput()
def createAudioOutput(self):
self.m_audioOutput = QAudioOutput(self.m_device, self.m_format)
self.m_audioOutput.notify.connect(self.notified)
self.m_audioOutput.stateChanged.connect(self.handleStateChanged)
self.m_generator.start()
self.m_audioOutput.start(self.m_generator)
self.m_volumeSlider.setValue(self.m_audioOutput.volume() * 100)
def deviceChanged(self, index):
self.m_pullTimer.stop()
self.m_generator.stop()
self.m_audioOutput.stop()
self.m_device = self.m_deviceBox.itemData(index)
self.createAudioOutput()
def volumeChanged(self, value):
if self.m_audioOutput is not None:
self.m_audioOutput.setVolume(value / 100.0)
def notified(self):
qWarning("bytesFree = %d, elapsedUSecs = %d, processedUSecs = %d" % (
self.m_audioOutput.bytesFree(),
self.m_audioOutput.elapsedUSecs(),
self.m_audioOutput.processedUSecs()))
def pullTimerExpired(self):
if self.m_audioOutput is not None and self.m_audioOutput.state() != QAudio.StoppedState:
chunks = self.m_audioOutput.bytesFree() // self.m_audioOutput.periodSize()
for _ in range(chunks):
data = self.m_generator.read(self.m_audioOutput.periodSize())
if data is None or len(data) != self.m_audioOutput.periodSize():
break
self.m_output.write(data)
def toggleMode(self):
self.m_pullTimer.stop()
self.m_audioOutput.stop()
if self.m_pullMode:
self.m_modeButton.setText(self.PULL_MODE_LABEL)
self.m_output = self.m_audioOutput.start()
self.m_pullMode = False
self.m_pullTimer.start(20)
else:
self.m_modeButton.setText(self.PUSH_MODE_LABEL)
self.m_pullMode = True
self.m_audioOutput.start(self.m_generator)
self.m_suspendResumeButton.setText(self.SUSPEND_LABEL)
def toggleSuspendResume(self):
if self.m_audioOutput.state() == QAudio.SuspendedState:
qWarning("status: Suspended, resume()")
self.m_audioOutput.resume()
self.m_suspendResumeButton.setText(self.SUSPEND_LABEL)
elif self.m_audioOutput.state() == QAudio.ActiveState:
qWarning("status: Active, suspend()")
self.m_audioOutput.suspend()
self.m_suspendResumeButton.setText(self.RESUME_LABEL)
elif self.m_audioOutput.state() == QAudio.StoppedState:
qWarning("status: Stopped, resume()")
self.m_audioOutput.resume()
self.m_suspendResumeButton.setText(self.SUSPEND_LABEL)
elif self.m_audioOutput.state() == QAudio.IdleState:
qWarning("status: IdleState")
stateMap = {
QAudio.ActiveState: "ActiveState",
QAudio.SuspendedState: "SuspendedState",
QAudio.StoppedState: "StoppedState",
QAudio.IdleState: "IdleState"}
def handleStateChanged(self, state):
qWarning("state = " + self.stateMap.get(state, "Unknown"))
if __name__ == '__main__':
import sys
app = QApplication(sys.argv)
app.setApplicationName("Audio Output Test")
audio = AudioTest()
audio.show()
sys.exit(app.exec_())
