The problem is that I am unable to play sound from a thread using QSoundEffect
or QMediaPlayer
. The only way that I got it to play sound once per program start is when I added:
QEventLoop loop;
loop.exec();
But this approach does not fit my need since I need the sound to be able to play more than once. Infinite loop count not what I need, but when used sound is played repeatedly til I end the program. No errors with neither of my approaches. So, what am I missing or using not the correct way?
By the way QSound works but I can't control loop count and volume with that, so I'm trying to get QSoundEffect or QMediaPlayer to work since they have this ability.
// main.cpp
QThread sound_thread;
QTimer sound_loop_timer;
Sound sound;
QObject::connect(&sound_loop_timer, SIGNAL(timeout()), &sound, SLOT(exec()));
sound_loop_timer.start(500);
sound_loop_timer.moveToThread(&sound_thread);
sound.moveToThread(&sound_thread);
sound_thread.start();
// Sound.h
class Sound : public QObject
{
Q_OBJECT
public:
Sound();
private slots:
void exec();
private:
void playSound();
QSoundEffect *sound_effect;
};
// Sound.cpp
Sound::Sound()
{
}
void Sound::exec(){
//...
playSound();
}
void Sound::playSound(){
sound_effect = new QSoundEffect;
sound_effect->setSource(QUrl("qrc:/sounds/audio/test.wav"));
// sound_effect->setLoopCount(QSoundEffect::Infinite);
sound_effect->setVolume(0.9);
sound_effect->play();
// QEventLoop loop;
// loop.exec();
QMediaPlayer player;// = new QMediaPlayer;
player.setMedia(QUrl::fromLocalFile("/home/path/audio/test.wav"));
player.setVolume(50);
player.play();
QEventLoop loop;
// loop.exec();
// loop.exit();
}
You don't have to handle the event loop by yourself since the default implementation of QThread::run()
do it for you.
I have made a simple example that plays a sound using QSoundEffect
in another thread.
As I was not sure about what exactly you want to do, I assumed the following statements:
SoundHandler
will handle the QSoundEffect
object.The below code is only meant to show you how to play a sound in a separate thread (what you asked for). If the above specifications does not fit the requirements of your use case, I think you can easily adapt the code to make it suit your needs.
test.h:
#ifndef TEST_H
#define TEST_H
#include <QMainWindow>
#include <QPushButton>
#include <QSoundEffect>
#include <QTimer>
#include <QThread>
class SoundHandler final : public QSoundEffect
{
Q_OBJECT
private:
QTimer * life_time_handler;
public:
SoundHandler(const QUrl & sound_path, int life_time_ms, QObject * parent = nullptr);
public slots:
void playSound();
void stopSound();
signals:
void hasFinished();
};
class TestWindow : public QMainWindow
{
Q_OBJECT
protected:
QPushButton * start_sound_thread;
QThread sound_thread;
SoundHandler * sound_effect;
public:
TestWindow();
~TestWindow();
};
#endif // TEST_H
test.cpp:
#include "test.h"
#include <QApplication>
SoundHandler::SoundHandler(const QUrl & sound_path, int life_time_ms, QObject * parent) : QSoundEffect(parent)
{
setSource(sound_path);
setVolume(0.5);
setLoopCount(QSoundEffect::Infinite);
life_time_handler = new QTimer(this);
life_time_handler->setInterval(life_time_ms);
life_time_handler->setSingleShot(true);
connect(life_time_handler, &QTimer::timeout, this, &SoundHandler::stopSound);
}
void SoundHandler::playSound()
{
life_time_handler->start();
play();
}
void SoundHandler::stopSound()
{
stop();
emit hasFinished();
}
TestWindow::TestWindow()
{
start_sound_thread = new QPushButton("Start");
this->setCentralWidget(start_sound_thread);
sound_effect = new SoundHandler(QUrl::fromLocalFile("../test/audio/test.wav"), 4000);
sound_effect->moveToThread(&sound_thread);
connect(&sound_thread, &QThread::finished, [&](){sound_effect->deleteLater();});
connect(&sound_thread, &QThread::started, sound_effect, &SoundHandler::playSound);
// Handle the thread termination
connect(sound_effect, &SoundHandler::hasFinished, [&](){
sound_thread.quit();
sound_thread.wait();
});
// Handle the thread launch
connect(start_sound_thread, &QPushButton::clicked, [&](){
sound_thread.start();
start_sound_thread->setEnabled(false);
});
}
TestWindow::~TestWindow()
{
if(sound_thread.isRunning())
{
sound_thread.quit();
sound_thread.wait();
}
}
int main(int argc, char ** argv)
{
QApplication app(argc, argv);
TestWindow tw;
tw.show();
return app.exec();
}
I've tested it and it worked fine.
Notes:
SoundHandler
a subclass of QSoundEffect
for convenience purposes but it is not required (it could have a QSoundEffect
object as a member instead of subclassing it).TestWindow
contains only a single QPushButton
to launch the sound in a separate thread. Once launched, the button becomes disabled.I hope it helps.