How to port QAudioOutput device(QAudioDeviceInfo::defaultOutputDevice()); to Qt6?

[Christian Ehrlicher]

@Urbi said in How to port QAudioOutput device(QAudioDeviceInfo::defaultOutputDevice()); to Qt6?:

WHAT is missing WHERE. Is that too much?

Is reading behind the first line of a documentation really so complicated?

"Header: #include <QAudioDevice>"

[Urbi]

@Christian-Ehrlicher
Thanks. Now it compiles, but I can hear no audio. May there be anything wrong in the following line?

effect.setSource(QUrl::fromLocalFile(binPath + "/sounds/1.wav"));

[Christian Ehrlicher]

@Urbi said in How to port QAudioOutput device(QAudioDeviceInfo::defaultOutputDevice()); to Qt6?:

o. May there be anything wrong in the following line?

Why not check out by yourself. QFile::exits() for example.

[Urbi]

@Christian-Ehrlicher
The file definitely exists. Even when I adress here the absolute path, no ausio can be heard.

[Christian Ehrlicher]

@Urbi said in How to port QAudioOutput device(QAudioDeviceInfo::defaultOutputDevice()); to Qt6?:

{
QAudioDevice info(QMediaDevices::defaultAudioOutput());
QString homePath = QDir::homePath();
if (play_) {
QSoundEffect effect;
effect.setSource(QUrl::fromLocalFile(binPath + "/sounds/1.wav"));
effect.play();
}
}

Then the next c++ question - how long does QSoundEffect live?

[Urbi]

@Christian-Ehrlicher
Unfortunately, still no success. I tried also the following code, however, again no audio (checked all sinks).

#include <QSoundEffect>
#include <QAudioOutput>
#include <QMediaDevices>
#include <QAudioDevice>
#include <QAudioSink>
#include <QDir>
#include <QCoreApplication>

{
  QAudioDevice device(QMediaDevices::defaultAudioOutput());
  QString homePath = QDir::homePath();
  QAudioFormat format;
  format.setSampleRate(8000);
  format.setChannelCount(1);
  format.setSampleFormat(QAudioFormat::UInt8);
  QAudioSink* audio = new QAudioSink(format, this);
  connect(audio, SIGNAL(stateChanged(QAudio::State)), this, SLOT(handleStateChanged(QAudio::State)));
    if (play_) {
       QFile effect;
            effect.setFileName(homePath + "/sounds/1.wav");
            effect.open(QIODevice::ReadOnly);
            audio->start(&effect);
    }
}

[Christian Ehrlicher]

@Urbi said in How to port QAudioOutput device(QAudioDeviceInfo::defaultOutputDevice()); to Qt6?:

if (play_) {
   QFile effect;
        effect.setFileName(homePath + "/sounds/1.wav");
        effect.open(QIODevice::ReadOnly);
        audio->start(&effect);
}

lifetime?

[Urbi]

@Christian-Ehrlicher
Give me the answer. I'n not a professional programmer ...

[Christian Ehrlicher]

@Urbi said in How to port QAudioOutput device(QAudioDeviceInfo::defaultOutputDevice()); to Qt6?:

I'n not a professional programmer ...

But you should understand the basic stuff of the programming language you're using. And I asked you to think about the lifetime of the objects in the code I copied from you - so maybe im some more words: how long does QFile effect; live? Not that I asked the exact same question or another object some hours ago.

[Urbi]

@Christian-Ehrlicher Christian, sorry, I am looking for a solution, not for playing games. If you knew who I am and what I have already manage to program you wouldn't treat me that way. Sorry, if this just a from some nerds... Good bye.

[Christian Ehrlicher]

@Urbi said in How to port QAudioOutput device(QAudioDeviceInfo::defaultOutputDevice()); to Qt6?:

. Sorry, if this just a from some nerds... Good bye.

No nerds - basic c++ understanding.

QFile effect lives until the closing bracket after audio->start() so how show audio be able to read anything from this QFile afterwards?

[Cobra91151]

@Urbi

@Christian-Ehrlicher is right, you need to know at least basic C++ to create your projects. @Urbi in your case your local QFile effect; variable gets out of scope (gets deleted) after the bracket, so no audio will be outputed. You must have it as a pointer and keep in mind to remove it later after you no longer need it to prevent a memory leak. You can use delete or deleteLater(). Please, check out my test code below.

Code:

   if (play) {
       QFile *effectFile = new QFile(this);
       effectFile->setFileName(QString("%1/%2").arg(homePath, "sounds/1.wav"));
       qDebug() << "Is file exists: " << effectFile->exists() << " | " << effectFile->fileName();
       effectFile->open(QIODevice::ReadOnly);
       audio->start(effectFile);
       effectFile->close();
       effectFile->deleteLater(); //removes the QFile object, or call - delete effectFile
   }

Also, you can use the qDebug() to check the console output for example to see if the file exists and other useful stuff. By the way, what Qt 6 version are you using for this project?

[Urbi]

@Cobra91151 It gives this compilation error: 'audio' was not declared in this scope; did you mean 'QAudio'?

[Urbi]

@Cobra91151 Sorry, I forgot that I had already deleted the lines

QAudioFormat format;
 format.setSampleRate(8000);
 format.setChannelCount(1);
 format.setSampleFormat(QAudioFormat::UInt8);
 QAudioSink* audio = new QAudioSink(format, this);

Now it compiles and sends "something" to the default audio device. However, I just hear a crackle, and the program crashes afterwards. But at least one step ahead ...

[Cobra91151]

@Urbi

It's audio object from your code above: QAudioSink *audio = new QAudioSink(format, this);
What Qt 6 version do you use? Because I got qt.multimedia.audiooutput: Failed to set up resampler issue, which is well known bug: https://bugreports.qt.io/browse/QTBUG-108383. This issue has been fixed in Qt 6.4.3.
So, I recommend check out the console output for the same issue?

[Cobra91151]

@Urbi

Then check out your program using the debugger to find out what causes the crash (debug mode only). It should point you to the right code section.

By the way, include this code in main function:

#ifdef QT_DEBUG
    qputenv("QT_FATAL_WARNINGS", "1");
    qputenv("QT_MESSAGE_PATTERN",
            "Type: %{type}\nProduct Name: %{appname}\nFile: %{file}\nLine: %{line}\nMethod: %{function}\nThreadID: %{threadid}\nThreadPtr: %{qthreadptr}\nMessage: %{message}");
#endif

Then run the debugger. It should provide more details about this issue.

[Urbi]

@Cobra91151 With these parameters, the wav file is correctly played. However, the program still crashes immediately after playing is finished.

#include <QSoundEffect>
#include <QAudioOutput>
#include <QMediaDevices>
#include <QAudioDevice>
#include <QAudioSink>
#include <QCoreApplication>
#include <QDir>

{
  QAudioDevice info(QMediaDevices::defaultAudioOutput());
  QString homePath = QDir::homePath();
  QAudioFormat format;
  format.setSampleRate(48000);
  format.setChannelCount(1);
  format.setSampleFormat(QAudioFormat::Int16);
  QAudioSink* audio = new QAudioSink(format, this);
  connect(audio, SIGNAL(stateChanged(QAudio::State)), this, SLOT(handleStateChanged(QAudio::State)));

  if (play_) {
      QFile *effectFile = new QFile(this);
      effectFile->setFileName(QString("%1/%2").arg(homePath, "/sounds/1.wav"));
      qDebug() << "Is file exists: " << effectFile->exists() << " | " << effectFile->fileName();
      effectFile->open(QIODevice::ReadOnly);
      audio->start(effectFile);
      effectFile->close();
      effectFile->deleteLater(); //removes the QFile object, or call - delete effectFile
  }
}

[Cobra91151]

@Urbi

I see your QAudioSink *audio is initialized but never deleted, this could be a memory leak which could lead to crash.

Code:

if (play_)  {
    QFile *effectFile = new QFile(this);
    effectFile->setFileName(QString("%1/%2").arg(homePath, "/sounds/1.wav"));
    qDebug() << "Is file exists: " << effectFile->exists() << " | " << effectFile->fileName();
    effectFile->open(QIODevice::ReadOnly);
    audio->start(effectFile);
    effectFile->close();
    effectFile->deleteLater(); //removes the QFile object, or call - delete effectFile
}

audio->deleteLater(); // removes QAudioSink object

Please, check out my post above regarding using the debugger.

[Urbi]

@Cobra91151 Ok, the last two lines are breaking it.

effectFile->close();

leads to an abrupt end of the played sound. And this line causes the program crashs:

effectFile->deleteLater(); //removes the QFile object, or call - delete effectFile

I will now try to consolidate my code. (It was just a simplified example I presented here.) Let's see if I can put the entire definition of audio device, format and so on somewhere else where it is only called once after program start.

Anyway, many thanks for your help, Cobra91151!

[Cobra91151]

@Urbi

It could close the file when audio is still running. It was just an example how to work with QFile. So, I recommend you to close and delete the file after the audio is finished. Happy coding!