void MainWindow::on_actionExportFrame_triggered()
{
    if (Settings.playerGPU() || Settings.playerPreviewScale()) {
        Mlt::GLWidget* glw = qobject_cast<Mlt::GLWidget*>(MLT.videoWidget());
        connect(glw, SIGNAL(imageReady()), SLOT(onGLWidgetImageReady()));
        MLT.setPreviewScale(0);
        glw->requestImage();
        MLT.refreshConsumer();
    } else {
        onGLWidgetImageReady();
    }
}
void MainWindow::on_actionExportFrame_triggered()
{
    if (Settings.playerGPU() || Settings.playerPreviewScale()) {
        Mlt::GLWidget* glw = qobject_cast<Mlt::GLWidget*>(MLT.videoWidget());
        connect(glw, SIGNAL(imageReady()), SLOT(onGLWidgetImageReady()));
        MLT.setPreviewScale(0);
        glw->requestImage();
        MLT.refreshConsumer();
    } else {
        onGLWidgetImageReady();
    }
}