How to use QSoundEffect (desparate to get simple code to work)

Snorkelbuckle

Hiya!

I am having a devil of a time to get a simple sound to play! First, I've read all the docs I can read and now I'm barfing up text. I have even compiled and run the sample application "Maroon in Trouble". Maroon works fine, it plays sound. I thought maybe it was my wav file giving a problem, so I confiscated wav file from Maroon and I still can't get it to work. This project was created using the new project wizard for a Qt Widgets Application.

OS: Windows 10, using ming32 compiler, Qt 5.13.0. BTW, I get same result with Qt 5.12.x, I upgraded to 5.13.0 thinking hoping it would help, the upgrade was a "Full uninstall, full install of new version". Here is my very simple QWidget app that won't play sound for nothing. Please, any advice here, how do I even troubleshoot this? Excluding the generated main.cpp. Also, the sound file is put into a resource file and it is directly taken from Maroon sample app.

Project file .pro

QT       += core gui multimedia

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = SoundTest
TEMPLATE = app

# The following define makes your compiler emit warnings if you use
# any feature of Qt which has been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

CONFIG += c++11

SOURCES += \
        main.cpp \
        mainwindow.cpp

HEADERS += \
        mainwindow.h

FORMS += \
        mainwindow.ui

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

RESOURCES += \
    sounds.qrc

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QSoundEffect>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

public slots:
    void playSound();

private:
    Ui::MainWindow *ui;


};

#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    connect(ui->actionMakeSomeNoise, &QAction::triggered, this, &MainWindow::playSound);
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::playSound()
{
    QSoundEffect effect;
    effect.setSource(QUrl("://projectile-action.wav"));
    effect.setLoopCount(10);
    effect.setMuted(false);
    effect.setVolume(1.0);
    effect.play();
}

JKSH

@Snorkelbuckle said in How to use QSoundEffect (desparate to get simple code to work):

QSoundEffect effect;

Fact #1: QSoundEffect::play() is asynchronous. This means the function returns before the sound finishes playing.
Fact #2: You created your QSoundEffect object as a local variable. This means the object gets destroyed when MainWindow::playSound() returns.
Result: Your QSoundEffect object gets destroyed before it has the chance to play the sound.

The fix? Make sure your QSoundEffect does not get destroyed too early. Make it a member variable of MainWindow, not a local variable of playSound().

Snorkelbuckle

Thanks for that, but now this still doesn't work. But the commented section does. When I check the status, it goes from 3 to 0.

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)

{
    ui->setupUi(this);
    efx = new QSoundEffect(this);
    efx->setSource(QUrl(":/projectile-action.wav"));
    efx->setVolume(0.90);
    efx->setLoopCount(2);
    connect(ui->actionMakeSomeNoise, &QAction::triggered, this, &MainWindow::playSound);
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::playSound()
{
    // THIS works when uncommented
    //QSound *efx2 = new QSound(":/projectile-action.wav");
    //efx2->setLoops(2);
    //efx2->play();

    ui->statusBar->showMessage(QString("efx status: %1").arg(efx->status()));
    efx->play();
}

Snorkelbuckle

Any other ideas, anybody? So far it is looking like a bug to me, can anybody post some code that actually works on Windows 10 for a QWidget app? Or is the updated code I posted technically correct?

mrjj

Hi
Your code works fine for me? ( win 10, Qt 5.12.3
Only change i did was to use fromLocalFile

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    efx = new QSoundEffect(this);
    efx->setSource(QUrl::fromLocalFile(":/1.wav"));
    efx->setVolume(0.90);
    efx->setLoopCount(2);
}

void MainWindow::on_pushButton_released()
{
    efx->play();
    ui->statusBar->showMessage(QString("efx status: %1").arg(efx->status()));
}

test project
https://www.dropbox.com/s/r7h92vtm6mrk6aa/SoundTest.zip?dl=0

Snorkelbuckle

Thank you, mrjj!

Works now! It was just that I needed the QUrl::fromLocalFile().

JKSH

@Snorkelbuckle said in How to use QSoundEffect (desparate to get simple code to work):

It was just that I needed the QUrl::fromLocalFile().

Or don't use QUrl (which you found when you wrote efx2)