Qt Reference Documentation

# videoplayer.cpp Example File

multimedia/videowidget/videoplayer.cpp

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     ** This file is part of the examples of the Qt Toolkit.
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     #include "videoplayer.h"

     #include "videowidget.h"

     #include <QtMultimedia>

     VideoPlayer::VideoPlayer(QWidget *parent)
         : QWidget(parent)
         , surface(0)
         , playButton(0)
         , positionSlider(0)
     {
         connect(&movie, SIGNAL(stateChanged(QMovie::MovieState)),
                 this, SLOT(movieStateChanged(QMovie::MovieState)));
         connect(&movie, SIGNAL(frameChanged(int)),
                 this, SLOT(frameChanged(int)));

         VideoWidget *videoWidget = new VideoWidget;
         surface = videoWidget->videoSurface();

         QAbstractButton *openButton = new QPushButton(tr("Open..."));
         connect(openButton, SIGNAL(clicked()), this, SLOT(openFile()));

         playButton = new QPushButton;
         playButton->setEnabled(false);
         playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));

         connect(playButton, SIGNAL(clicked()),
                 this, SLOT(play()));

         positionSlider = new QSlider(Qt::Horizontal);
         positionSlider->setRange(0, 0);

         connect(positionSlider, SIGNAL(sliderMoved(int)),
                 this, SLOT(setPosition(int)));

         connect(&movie, SIGNAL(frameChanged(int)),
                 positionSlider, SLOT(setValue(int)));

         QBoxLayout *controlLayout = new QHBoxLayout;
         controlLayout->setMargin(0);
         controlLayout->addWidget(openButton);
         controlLayout->addWidget(playButton);
         controlLayout->addWidget(positionSlider);

         QBoxLayout *layout = new QVBoxLayout;
         layout->addWidget(videoWidget);
         layout->addLayout(controlLayout);

         setLayout(layout);
     }

     VideoPlayer::~VideoPlayer()
     {
     }

     void VideoPlayer::openFile()
     {
         QStringList supportedFormats;
         foreach (QString fmt, QMovie::supportedFormats())
             supportedFormats << fmt;
         foreach (QString fmt, QImageReader::supportedImageFormats())
             supportedFormats << fmt;

         QString filter = "Images (";
         foreach ( QString fmt, supportedFormats) {
             filter.append(QString("*.%1 ").arg(fmt));
         }
         filter.append(")");

         QString fileName = QFileDialog::getOpenFileName(this, tr("Open Movie"),
                 QDir::homePath(), filter);

         if (!fileName.isEmpty()) {
             surface->stop();

             movie.setFileName(fileName);

             playButton->setEnabled(true);
             positionSlider->setMaximum(movie.frameCount());

             movie.jumpToFrame(0);
         }
     }

     void VideoPlayer::play()
     {
         switch(movie.state()) {
         case QMovie::NotRunning:
             movie.start();
             break;
         case QMovie::Paused:
             movie.setPaused(false);
             break;
         case QMovie::Running:
             movie.setPaused(true);
             break;
         }
     }

     void VideoPlayer::movieStateChanged(QMovie::MovieState state)
     {
         switch(state) {
         case QMovie::NotRunning:
         case QMovie::Paused:
             playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
             break;
         case QMovie::Running:
             playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPause));
             break;
         }
     }

     void VideoPlayer::frameChanged(int frame)
     {
         if (!presentImage(movie.currentImage())) {
             movie.stop();
             playButton->setEnabled(false);
             positionSlider->setMaximum(0);
         } else {
             positionSlider->setValue(frame);
         }
     }

     void VideoPlayer::setPosition(int frame)
     {
         movie.jumpToFrame(frame);
     }

     bool VideoPlayer::presentImage(const QImage &image)
     {
         QVideoFrame frame(image);

         if (!frame.isValid())
             return false;

         QVideoSurfaceFormat currentFormat = surface->surfaceFormat();

         if (frame.pixelFormat() != currentFormat.pixelFormat()
                 || frame.size() != currentFormat.frameSize()) {
             QVideoSurfaceFormat format(frame.size(), frame.pixelFormat());

             if (!surface->start(format))
                 return false;
         }

         if (!surface->present(frame)) {
             surface->stop();

             return false;
         } else {
             return true;
         }
     }