Can't play again QSoundEffect when inside a QThread

mipr

Hi,

I have created a class with a QSoundEffect and a QThread inside, the goal is to play the sound inside the thread.
My code worked, I can play the sound once thanks to this code :

SoundAlert.h :

#ifndef SOUNDALERT_H
#define SOUNDALERT_H

#include <QObject>
#include <QSoundEffect>

class SoundAlert : public QObject
{
 Q_OBJECT
 public:
    SoundAlert(QUrl soundUrl);
    ~SoundAlert();
 public slots:
    void play();

 private:
    QSoundEffect* _sound;
    QThread* _thread;
};

#endif // SOUNDALERT_H

SoundAlert.cpp :

#include "SoundAlert.h"
#include "MyApplication.h"

SoundAlert::SoundAlert(QUrl soundUrl){
 _sound = new QSoundEffect;
 _sound->setSource(soundUrl);
 _thread = new QThread;
 _sound->moveToThread(_thread);
 _thread->start();

 QObject::connect(_sound, &QSoundEffect;::playingChanged, this, [=](){
   qDebug() << "SoundAlert playingChanged:" << _sound->isPlaying();
 });
}

SoundAlert::~SoundAlert(){
 _thread->quit();
 _sound->deleteLater();
 _thread->deleteLater();
}

void SoundAlert::play(){
 if(_sound->status() == _sound->Ready && !_sound->isPlaying()){
   _sound->play();
 }
}

However, if I try to play the sound many times thanks to a recurring signal, it plays just once.

The test !_sound->isPlaying() is used to avoid stopping sound before the end.

The issue is the playing attribut of the QSoundEffect that is never change to false. I've tried without the QThread and I have no issue, it plays the sound many times and I can see the playing attribut as false. Do you have an idea?

My Qt version is 5.15.7 and I am on Windows.

Edit: I modified the code to be more complete.

Christian Ehrlicher

@mipr said in Can't play again QSoundEffect when inside a QThread:

My Qt version is 5.15.7 and I am on Windows.

Since this is a commercial version you should also ask the Qt support for help.
A fully, minimal example would be good though.

mipr

@Christian-Ehrlicher Thanks for your answer.

I have just contacted Qt support, I don't usually use this method. Thanks for your advice!

I changed the code of my original post. I hope having these complete files can help, I can't release more as the application is quite large.
The signal connected to the play() method (of SoundAlert) is equivalent to a QTimer with an infinite loop.

Christian Ehrlicher

@mipr said in Can't play again QSoundEffect when inside a QThread:

The signal connected to the play() method (of SoundAlert) is equivalent to a QTimer with an infinite loop.

Can you show us the connection?

mipr

@Christian-Ehrlicher I tried with a QTimer instead of the other connection (because it is hard to understand without the context) and I find the same behavior.

SoundAlert* soundAlert = new SoundAlert(
    QUrl::fromLocalFile(":/resources/sounds/mySound.wav"));
QTimer* testTimer = new QTimer();
testTimer->setInterval(2000);
QObject::connect(testTimer, &QTimer::timeout, soundAlert, &SoundAlert::play);
testTimer->start();

Without the thread part, the sound is played many times. And with, the sound is played once.

When I remove the thread part I just comment these two lines (SoundAlert.cpp):

//_sound->moveToThread(_thread);
//_thread->start();