qt.multimedia.player: Warning: "Failed to connect: Connection refused"

[CompSciDude]

@jsulm It is not the exact code, but here is a very similar example:

#include <memory>

#include <QApplication>
#include <QAudioOutput>
#include <QFileInfo>
#include <QMediaPlayer>
#include <QObject>
#include <QString>
#include <QUrl>
#include <QWidget>

class SoundEffect : public QObject {
  Q_OBJECT

public:
  SoundEffect(QObject* aParent, const QString& aSound)
  : QObject(aParent)
  , mSound(aSound) {
  }

  void PlaySound() {
    QFileInfo mSoundPath{mSound};
    QUrl mSoundUrl{mSoundPath.absoluteFilePath()};
    mOutput.setVolume(1.0);
    mPlayer.setAudioOutput(&mOutput);
    mPlayer.setSource(mSoundUrl);
    mPlayer.setLoops(QMediaPlayer::Infinite);
    mPlayer.play();
  }

private:
  QString mSound;
  QAudioOutput mOutput;
  QMediaPlayer mPlayer;
};

int main(int aArgc, char** aArgv) {
  QApplication theApp{aArgc, aArgv);

  auto theWidget = std::make_unique<QWidget>(nullptr);
  theWidget->show();
  SoundEffect theEffect{theWidget.get(), "mySound.mp3"};
  theEffect.PlaySound();
  
  int exitCode{theApp.exec()};
  return exitCode;
}

[Christian Ehrlicher]

@CompSciDude The QUrl ctor does not take a local file path as argument so your QUrl is empty and nothing can be played.

[CompSciDude]

@Christian-Ehrlicher This is the output of qDebug() << "mSoundUrl: " << mSoundUrl;

mSoundUrl:  QUrl("/home/compscidude/build-TestSound-Qt6-Debug/source/mySound.mp3")

To me, that means QUrl is not empty. Please correct me if I am not understanding the output.

The sound plays on Windows, but I get the qt.multimedia.player: Warning: "Failed to connect: Connection refused" on Linux.

[Christian Ehrlicher]

@CompSciDude said in qt.multimedia.player: Warning: "Failed to connect: Connection refused":

To me, that means QUrl is not empty.

This is not a valid url. Please follow my links and use the correct function to create a valid url from a local file...

[CompSciDude]

@Christian-Ehrlicher Ok, I did that, but I am still getting qt.multimedia.player: Warning: "Failed to connect: Connection refused".

Code

#include <memory>

#include <QApplication>
#include <QAudioOutput>
#include <QFileInfo>
#include <QMediaPlayer>
#include <QObject>
#include <QString>
#include <QUrl>
#include <QWidget>

class SoundEffect : public QObject {
  Q_OBJECT

public:
  SoundEffect(QObject* aParent, const QString& aSound)
  : QObject(aParent)
  , mSound(aSound) {
  }

  void PlaySound() {
    QFileInfo soundPath{mSound};
    QString soundAbsPath{soundPath.absoluteFilePath()};
    qDebug() << "soundAbsPath: " << soundAbsPath;
    auto soundUrl = QUrl::fromLocalFile(soundAbsPath);
    qDebug() << "soundUrl: " << soundUrl;
    mOutput.setVolume(1.0);
    mPlayer.setAudioOutput(&mOutput);
    mPlayer.setSource(soundUrl);
    mPlayer.setLoops(QMediaPlayer::Infinite);
    mPlayer.play();
  }

private:
  QString mSound;
  QAudioOutput mOutput;
  QMediaPlayer mPlayer;
};

int main(int aArgc, char** aArgv) {
  QApplication theApp{aArgc, aArgv};

  auto theWidget = std::make_unique<QWidget>(nullptr);
  theWidget->show();
  SoundEffect theEffect{theWidget.get(), "mySound.mp3"};
  theEffect.PlaySound();
  
  int exitCode{theApp.exec()};
  return exitCode;
}

Console output

Gtk-Message: 10:01:16.982: Failed to load module "xapp-gtk3-module"
Gtk-Message: 10:01:16.982: Failed to load module "unity-gtk-module"
Gtk-Message: 10:01:17.027: Failed to load module "canberra-gtk-module"
Gtk-Message: 10:01:17.028: Failed to load module "canberra-gtk-module"
Qt: Session management error: None of the authentication protocols specified are supported
soundAbsPath:  "/home/compscidude/build-TestSound-Qt6-Debug/source/mySound.mp3"
soundUrl:  QUrl("file:///home/compscidude/build-TestSound-Qt6-Debug/source/mySound.mp3")
[ALSOFT] (EE) Failed to set real-time priority for thread: Operation not permitted (1)
qt.multimedia.player: Warning: "Failed to connect: Connection refused"
qt.multimedia.player: Warning: "Failed to connect: Connection refused"

I included all of the warning messages I am getting in case that helps diagnose the issue. I do not quite understand any of them.

[CompSciDude]

Side-note: I found a documentation page discussing GStreamer packages for QtMultimedia. https://doc.qt.io/qt-6.2/videooverview.html#supported-media-formats.

I will verify if I have the correct packages installed and then try again.

[CompSciDude]

I verified I had the correct packages installed and it still gives me the connection refused error with no sound playing.

[FinnTheHuman]

I'm getting same error on similar problem
Function I'm using:

void MainWindow::on_Browse_clicked()
{
    QString filePath = "file:/";
    filePath += QFileDialog::getOpenFileName(this, tr("Select Audio File"), "", tr("MP3 Files (*.mp3)"));
    qDebug() << filePath;

    mediaPlayer = new QMediaPlayer();
    audioOutput = new QAudioOutput();

    mediaPlayer->setAudioOutput(audioOutput);
    qDebug() << mediaPlayer->audioOutput();


    mediaPlayer->setSource(QUrl::fromLocalFile(filePath));
    mediaPlayer->setLoops(QMediaPlayer::Infinite);
    audioOutput->setVolume(50);
    ui->file_name->setText(filePath);
}

and this is the error I am getting:

"file://home/Admin/Desktop/music.mp3"
[ALSOFT] (EE) Failed to set real-time priority for thread: Operation not permitted (1)
QAudioOutput(0x55a8c4ddaa70)
qt.multimedia.player: Unable to set the pipeline to the paused state.
qt.multimedia.player: Warning: "Failed to connect: Connection refused"

[CompSciDude]

Ok, I tried reconfiguring to build Qt from source and it says it does not have GStreamer support. That might be the issue. Please correct me if I am wrong, but I will investigate this.

[CompSciDude]

I installed the libgstreamermm-1.0-dev package and doing that seemed to make the configure find GStreamer. I am going to rebuild the source and try running my application again to see if this will fix the issue.

[CompSciDude]

Well, I rebuilt Qt 6.2.4 source, but it still gives me the error. I am out of ideas.

[CompSciDude]

I figured out a workaround that resolves this problem: run the application via the command line.

[CompSciDude]

It is possible there is an issue with Qt Creator. I saw the error when running inside Qt Creator, but not when running from the command line.