Audio not playing from .qrc resources

Xena_o

hello

i'm using Qt 5.15.2, i'm trying to play a music from .qr resources file, but the file is not playing.

(no error message, just audio wont play)

It will play if i specify a local directory, but this is not fine for what i want.

QMediaPlayer * player = new QMediaPlayer(this);

 player->setMedia(QUrl::fromLocalFile((":/music/sound.mp3")));

 player->setVolume(50);
    player->play();

also tried :

    player->setMedia(QUrl::fromLocalFile((":/music/music/sound.mp3")));

both do not work.

this works :

    player->setMedia(QUrl::fromLocalFile(("C:/user/documents/sound.mp3")));

i couldnt find any viable code anywhere, any idea why it is not reading the audio from the resources file?

thanks

sierdzio

With QRC, it's always a bit tricky, but I think it should work. Some things to try:

verify that file exists in QRC with QFile / QFileInfo
try "qrc://music/sound.mp3" and "qrc:/music/sound.mp3"
do not use QUrl::fromLocalFile but a regular QUrl constructor player->setMedia(QUrl("qrc:/music/sound.mp3"));

nagesh

@Xena_o
As per qt doc.. If you want to know what error happened while loading media..

Listen for the mediaStatusChanged() and error() signals to be notified when the media is loaded and when an error occurs during loading.

https://doc.qt.io/qt-5/qmediaplayer.html#setMedia

Xena_o

@sierdzio i tried all your variants and some more based on your variants, none of them work unfortunatly

@nagesh error() returns : QMediaPlayer::NoError and mediaStatus() returns QMediaPlayer::LoadingMedia

sierdzio

In that case, you should be able to get it working by opening the MP3 with QFile and passing it as second argument to setMedia() https://doc.qt.io/qt-5/qmediaplayer.html#setMedia:

QFile file("qrc://music/sound.mp3");
if (file.open(QFile::Read)) {
  player->setMedia("qrc://music/sound.mp3", &file);
} else {
  qDebug() << "Oops!";
}

kshegunov

Is the resource loaded at runtime or compiled into the binary? You should make sure the file's available for reading, like @sierdzio suggested.

Xena_o

screenshot

for some reasons this code is not fine, i added #include <QFile>

seems cannot use audio from resources

@kshegunov it is available for reading, the test of opening it from local directory works well, seems just from resources it wont open

kshegunov

@Xena_o said in Audio not playing from .qrc resources:

for some reasons this code is not fine, i added #include <QFile>

Yet didn't check the QMediaPlayer::setMedia documentation - the inline annotations already tell you something's wrong on that row. The QMediaContent object has an implicit constructor from QUrl that's why you can use QUrl directly. Try something like:

QFile file(":/music/sound.mp3"); //< QFile doesn't know about protocols
if (file.open(QFile::Read))
  player->setMedia(QMediaContent(nullptr), &file);
else
  qDebug() << "Oops!";

@kshegunov it is available for reading, the test of opening it from local directory works well, seems just from resources it wont open

Available for reading from the resource! Also please answer the question as well.

Xena_o

@kshegunov here is final code

QFile file(":/music/music/sound.mp3");
    if (file.open(QIODevice::ReadOnly)) {
      player->setMedia(QMediaContent(nullptr), &file);
    } else {
      qDebug() << "Oops!";
    }

the accepted code is : QIODevice::ReadOnly and not QFile::Read
the file is in resources.qrc, i dont know how to figure if it is available

the ouptput: no oops, and QMediaPlayer::NoError QMediaPlayer::LoadingMedia

but still the sound is not playing. so far if i well understand, it is loading it, but thats it, not playing

player->setVolume(50);
    player->play();

this is doing nothing

kshegunov

@Xena_o said in Audio not playing from .qrc resources:

the accepted code is : QIODevice::ReadOnly and not QFile::Read

Yes, I don't compile example code before I post it, so there may be minor errors.

What does this output, have you checked the signals that are raised?

QObject::connect(player, &QMediaPlayer::bufferStatusChanged, this, [this] (int percent) -> void  {
    qDebug() << "QMediaPlayer::bufferStatusChanged" << percent;
});
QObject::connect(player, &QMediaPlayer::durationChanged, this, [this] (qint64 duration) -> void  {
    qDebug() << "QMediaPlayer::durationChanged" << duration;
});
QObject::connect(player, &QMediaPlayer::error, this, [this] (QMediaPlayer::Error code) -> void  {
    qDebug() << "QMediaPlayer::Error" << code;
});
QObject::connect(player, &QMediaPlayer::mediaStatusChanged, this, [this] (QMediaPlayer::MediaStatus status) -> void  {
    qDebug() << "QMediaPlayer::mediaStatusChanged" << status;
});
QObject::connect(player, &QMediaPlayer::stateChanged, this, [this] (QMediaPlayer::State state) -> void  {
    qDebug() << "QMediaPlayer::stateChanged" << state;
});

QFile file(":/music/music/sound.mp3");
if (file.open(QIODevice::ReadOnly)) {
    player->setMedia(QMediaContent(nullptr), &file);
} else {
    qDebug() << "Oops!";
}
player->setVolume(50);
player->play();

Xena_o

@kshegunov alright it is saying the media is invalid :

QMediaPlayer::mediaStatusChanged QMediaPlayer::LoadingMedia
QMediaPlayer::stateChanged QMediaPlayer::PlayingState
QMediaPlayer::mediaStatusChanged QMediaPlayer::InvalidMedia

but that is not true, it is an mp3 file, and it is reading from local directory, so why is it invalid from Resources ?!

kshegunov

As I said make absolutely certain that the file can be read.

const QString filePath(":/music/sound.mp3")
Q_ASSERT(QFile::exists(filePath));
...
QFile file(filePath);
if (file.open(QIODevice::ReadOnly)) {
   ...

Xena_o

@kshegunov Q_ASSERT(QFile::exists(filePath)); is not outputing anything and app is not crashing, so this means the file is available right? but still it is an invalid media, i tried to convert to .wav but still it is an invalid media !

Xena_o

i saw a post where people are copying the audio file from the resources file to a temporary local directory, then playing it from the local directory, then deleting it.

This means it is not possible to play audio from resources, its kind of insane, isnt it ?

Xena_o

const QString filePath(":/music/music/sound.mp3");
    Q_ASSERT(QFile::exists(filePath));

    QFile file2(QDir::tempPath() + "/temp0.mp3");

    if (file2.open(QIODevice::ReadWrite))
    {
        QFile workFile(filePath);
        if(workFile.open(QIODevice::ReadOnly))
        {
          file2.write(workFile.readAll());
          workFile.close();
        }

        file2.close();
    }
    player->setMedia(QUrl::fromLocalFile((QDir::tempPath() + "/temp0.mp3")));
    player->setVolume(50);
    player->play();

this code is working, but its too bad i need to copy from resources to temporary file to be able to play the audio, that is bad...

Pl45m4

@Xena_o said in Audio not playing from .qrc resources:

This means it is not possible to play audio from resources, its kind of insane, isnt it ?

I don't think that it's not possible.
Have you tried it using QSound instead of QMediaPlayer?

@aha_1980 said that it worked:

https://forum.qt.io/topic/88581/how-to-play-a-wav-file-that-is-defined-in-resource-file/8

How does your resource file look like?

Xena_o

@Pl45m4 wow i get a progress with this !

QSound::play(":/music/music/sound.mp3"); throws
QSoundEffect(qaudio): Error decoding source file::/music/music/sound.mp3

but

QSound::play(":/music/music/sound.wav"); (i converted the file) this one is WORKING !

too bad it doesnt handle mp3 or maybe i need add extra params, will look it.

edit: seems QSound do not support mp3, too bad, well wav is better than nothing

thanks to everybody for participation and help :-)

nagesh

@Xena_o I have checked by adding .mp3 files to resource in QT musicplayer example,
and it's working perfectly fine.

I have accessed the url using

QUrl url = QUrl("qrc:///music/sound.mp3");
 player->setMedia(url);
player->play();

looks like there is no need to copy into temp file.

Got hint from Qt Doc for resources
https://doc.qt.io/qt-5/resources.html

For example, the file path :/images/cut.png or the URL qrc:///images/cut.png would give 
access to the cut.png file, whose location in the application's source tree 
is images/cut.png.

Xena_o

@nagesh wonderful ! thank you ! i tested it is working. AMediaPlayer offers more control than QSound.

8Observer8

My example works with Qt 6.2.4. You can download it from DropBox here. Many thanks to the guys in this topic: How to play sounds using QMediaPlayer

media-player-qt6-cpp.pro

QT       += core gui multimedia

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++17

# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += \
    main.cpp \
    widget.cpp

HEADERS += \
    widget.h

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

RESOURCES += \
    audio.qrc

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QtWidgets/QWidget>
#include <QtMultimedia/QMediaPlayer>

class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = nullptr);
    ~Widget();

private slots:
    void play();

private:
    QMediaPlayer mediaPlayer;
};
#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include <QtCore/QUrl>
#include <QtWidgets/QPushButton>
#include <QtMultimedia/QAudioOutput>

Widget::Widget(QWidget *parent)
    : QWidget(parent)
{
    mediaPlayer.setSource(QUrl("qrc:/assets/audio/music.wav"));
    mediaPlayer.setAudioOutput(new QAudioOutput);

    QPushButton *playButton = new QPushButton("Play", this);
    connect(playButton, &QPushButton::pressed, this, &Widget::play);

    connect(&mediaPlayer, &QMediaPlayer::mediaStatusChanged,
            [=](QMediaPlayer::MediaStatus status) -> void{ qDebug() << "QMediaPlayer::mediaStatusChanged" << status;}
    );
}

Widget::~Widget()
{
}

void Widget::play()
{
    mediaPlayer.play();
    qDebug() << "play";
}

main.cpp

#include "widget.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();
    return a.exec();
}