videotestsrc gst-pipeline on i.mx8 arm processor shows just white screen

arrow54

This code seems to run fine but just produces a window with white rather than the normal videotestsrc test pattern. I'm new to this so I have no clue even how to debug this.

Maybe there is something simple with the pipeline I'm missing?

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QAbstractVideoSurface>

class Surface : public QAbstractVideoSurface
{
public:
    Surface(QObject *p) : QAbstractVideoSurface(p) { }
    QList<QVideoFrame::PixelFormat> supportedPixelFormats(QAbstractVideoBuffer::HandleType) const override
    {
        // Make sure that the driver supports this pixel format.
        return QList<QVideoFrame::PixelFormat>() << QVideoFrame::Format_YUYV;
    }

    // Video frames are handled here.
    bool present(const QVideoFrame &) override { return true; }
};

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    player = new QMediaPlayer;
    player->setVideoOutput(new Surface(player));
    player->setMedia(QUrl("gst-pipeline: videotestsrc ! qtvideosink"));
    player->play();
}

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