How to use the QMediaPlayer module to connect to a rtsp stream?

Ylvy

I'm streaming a window using FFmpeg and I'm trying to connect the stream to a QMediaPlayer widget, like:

#include <QMediaPlayer>
#include <QVideoWidget>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QMediaPlayer player;
    QVideoWidget videoWidget;
    player.setVideoOutput(&videoWidget);
    videoWidget.show();

    QString streamUrl = "rtsp://....:8554/stream"; 
    //QString streamUrl = "rtsp://.....129:8554/stream;tcp"

    player.setSource(QUrl(streamUrl));
    player.play();

    return a.exec();
}

It's not working and I'm getting these errors on the console:

Exception thrown at 0x00007FF909E5CB69 in MediaPlayer.exe: Microsoft C++ exception: bad_hresult at memory location 0x0000007FD0FCA490.
Exception thrown at 0x00007FF909E5CB69 in MediaPlayer.exe: Microsoft C++ exception: bad_hresult at memory location 0x0000007FD0FCA468.
Exception thrown at 0x00007FF909E5CB69 in MediaPlayer.exe: Microsoft C++ exception: [rethrow] at memory location 0x0000000000000000.
Exception thrown at 0x00007FF909E5CB69 in MediaPlayer.exe: Microsoft C++ exception: bad_hresult at memory location 0x0000007FD0FCA468.
Exception thrown at 0x00007FF909E5CB69 (KernelBase.dll) in MediaPlayer.exe: WinRT originate error - 0xC00D2EF9 : 'The text associated with this error code could not be found.'.
handleSessionEvent: serious error =  0xC00D2EF9
Exception thrown at 0x00007FF909E5CB69 (KernelBase.dll) in MediaPlayer.exe: WinRT originate error - 0xC00D2EF9 : 'The text associated with this error code could not be found.'.
handleSessionEvent: serious error =  0xC00D2EF9

Testing the same streamUrl on vlc it does work correctly.
Im testing on Qt 6.5, Win10

Christian Ehrlicher

@Ylvy See https://forum.qt.io/topic/144882/streaming-and-showing-video-using-a-qvideowidget-object-ffmpeg/5 and the link to the bug report in there

Ylvy

@Christian-Ehrlicher I have downloaded the 6.6.0 source, but now it is stuck for many seconds when it read the line
player->setSource(QUrl("rtsp://....129:8554/stream"));

and then debug this message:
qt.multimedia.ffmpeg.mediadataholder: AVStream duration -9223372036854775808 is invalid. Taking it from the metadata

Also, connect(player, &QMediaPlayer::errorOccurred prints:
Error: "Invalid argument"

class MediaPlayer : public QObject
{
    Q_OBJECT
public:
    MediaPlayer (QObject* parent = nullptr) : QObject(parent)
    {
        player = new QMediaPlayer;
        player->setSource(QUrl("rtsp://....129:8554/stream"));
        connect(player, &QMediaPlayer::errorOccurred, this, [this](QMediaPlayer::Error error, const QString& errorString)
        {
            qDebug() << "Error:" << errorString;
        });

        videoWidget = new QVideoWidget;
        player->setVideoOutput(videoWidget);

        videoWidget->show();
        player->play();
    }

private:
    QMediaPlayer* player;
    QVideoWidget* videoWidget;
};

Christian Ehrlicher

The solution in the bug report was to switch back to another backend, not using some beta software...

Ylvy

@Christian-Ehrlicher I know, was the first thing I tried, but it still didn't work in both versions.

Im not sure if I tested it correctly, but what i tried was calling qputenv after the QApplication line.

qputenv("QT_MEDIA_BACKEND", "windows");

JonB

@Ylvy
I think you will find the whole point is that you must put the qputenv() statement before the line creating the QApplication so that the application respects your desired media backend!