Qt 5.9 | Qt Multimedia | Media Player Example | player.cpp Example File

Qt 5.9.4 Reference Documentation

# player.cpp Example File

multimediawidgets/player/player.cpp

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      #include "player.h"

      #include "playercontrols.h"
      #include "playlistmodel.h"
      #include "histogramwidget.h"

      #include <QMediaService>
      #include <QMediaPlaylist>
      #include <QVideoProbe>
      #include <QAudioProbe>
      #include <QMediaMetaData>
      #include <QtWidgets>

      Player::Player(QWidget *parent)
          : QWidget(parent)
          , videoWidget(0)
          , coverLabel(0)
          , slider(0)
          , colorDialog(0)
      {
          player = new QMediaPlayer(this);
          // owned by PlaylistModel
          playlist = new QMediaPlaylist();
          player->setPlaylist(playlist);

          connect(player, SIGNAL(durationChanged(qint64)), SLOT(durationChanged(qint64)));
          connect(player, SIGNAL(positionChanged(qint64)), SLOT(positionChanged(qint64)));
          connect(player, SIGNAL(metaDataChanged()), SLOT(metaDataChanged()));
          connect(playlist, SIGNAL(currentIndexChanged(int)), SLOT(playlistPositionChanged(int)));
          connect(player, SIGNAL(mediaStatusChanged(QMediaPlayer::MediaStatus)),
                  this, SLOT(statusChanged(QMediaPlayer::MediaStatus)));
          connect(player, SIGNAL(bufferStatusChanged(int)), this, SLOT(bufferingProgress(int)));
          connect(player, SIGNAL(videoAvailableChanged(bool)), this, SLOT(videoAvailableChanged(bool)));
          connect(player, SIGNAL(error(QMediaPlayer::Error)), this, SLOT(displayErrorMessage()));
          connect(player, &QMediaPlayer::stateChanged, this, &Player::stateChanged);

          videoWidget = new VideoWidget(this);
          player->setVideoOutput(videoWidget);

          playlistModel = new PlaylistModel(this);
          playlistModel->setPlaylist(playlist);

          playlistView = new QListView(this);
          playlistView->setModel(playlistModel);
          playlistView->setCurrentIndex(playlistModel->index(playlist->currentIndex(), 0));

          connect(playlistView, SIGNAL(activated(QModelIndex)), this, SLOT(jump(QModelIndex)));

          slider = new QSlider(Qt::Horizontal, this);
          slider->setRange(0, player->duration() / 1000);

          labelDuration = new QLabel(this);
          connect(slider, SIGNAL(sliderMoved(int)), this, SLOT(seek(int)));

          labelHistogram = new QLabel(this);
          labelHistogram->setText("Histogram:");
          videoHistogram = new HistogramWidget(this);
          audioHistogram = new HistogramWidget(this);
          QHBoxLayout *histogramLayout = new QHBoxLayout;
          histogramLayout->addWidget(labelHistogram);
          histogramLayout->addWidget(videoHistogram, 1);
          histogramLayout->addWidget(audioHistogram, 2);

          videoProbe = new QVideoProbe(this);
          connect(videoProbe, SIGNAL(videoFrameProbed(QVideoFrame)), videoHistogram, SLOT(processFrame(QVideoFrame)));
          videoProbe->setSource(player);

          audioProbe = new QAudioProbe(this);
          connect(audioProbe, SIGNAL(audioBufferProbed(QAudioBuffer)), audioHistogram, SLOT(processBuffer(QAudioBuffer)));
          audioProbe->setSource(player);

          QPushButton *openButton = new QPushButton(tr("Open"), this);

          connect(openButton, SIGNAL(clicked()), this, SLOT(open()));

          PlayerControls *controls = new PlayerControls(this);
          controls->setState(player->state());
          controls->setVolume(player->volume());
          controls->setMuted(controls->isMuted());

          connect(controls, SIGNAL(play()), player, SLOT(play()));
          connect(controls, SIGNAL(pause()), player, SLOT(pause()));
          connect(controls, SIGNAL(stop()), player, SLOT(stop()));
          connect(controls, SIGNAL(next()), playlist, SLOT(next()));
          connect(controls, SIGNAL(previous()), this, SLOT(previousClicked()));
          connect(controls, SIGNAL(changeVolume(int)), player, SLOT(setVolume(int)));
          connect(controls, SIGNAL(changeMuting(bool)), player, SLOT(setMuted(bool)));
          connect(controls, SIGNAL(changeRate(qreal)), player, SLOT(setPlaybackRate(qreal)));

          connect(controls, SIGNAL(stop()), videoWidget, SLOT(update()));

          connect(player, SIGNAL(stateChanged(QMediaPlayer::State)),
                  controls, SLOT(setState(QMediaPlayer::State)));
          connect(player, SIGNAL(volumeChanged(int)), controls, SLOT(setVolume(int)));
          connect(player, SIGNAL(mutedChanged(bool)), controls, SLOT(setMuted(bool)));

          fullScreenButton = new QPushButton(tr("FullScreen"), this);
          fullScreenButton->setCheckable(true);

          colorButton = new QPushButton(tr("Color Options..."), this);
          colorButton->setEnabled(false);
          connect(colorButton, SIGNAL(clicked()), this, SLOT(showColorDialog()));

          QBoxLayout *displayLayout = new QHBoxLayout;
          displayLayout->addWidget(videoWidget, 2);
          displayLayout->addWidget(playlistView);

          QBoxLayout *controlLayout = new QHBoxLayout;
          controlLayout->setMargin(0);
          controlLayout->addWidget(openButton);
          controlLayout->addStretch(1);
          controlLayout->addWidget(controls);
          controlLayout->addStretch(1);
          controlLayout->addWidget(fullScreenButton);
          controlLayout->addWidget(colorButton);

          QBoxLayout *layout = new QVBoxLayout;
          layout->addLayout(displayLayout);
          QHBoxLayout *hLayout = new QHBoxLayout;
          hLayout->addWidget(slider);
          hLayout->addWidget(labelDuration);
          layout->addLayout(hLayout);
          layout->addLayout(controlLayout);
          layout->addLayout(histogramLayout);

          setLayout(layout);

          if (!isPlayerAvailable()) {
              QMessageBox::warning(this, tr("Service not available"),
                                   tr("The QMediaPlayer object does not have a valid service.\n"\
                                      "Please check the media service plugins are installed."));

              controls->setEnabled(false);
              playlistView->setEnabled(false);
              openButton->setEnabled(false);
              colorButton->setEnabled(false);
              fullScreenButton->setEnabled(false);
          }

          metaDataChanged();
      }

      Player::~Player()
      {
      }

      bool Player::isPlayerAvailable() const
      {
          return player->isAvailable();
      }

      void Player::open()
      {
          QFileDialog fileDialog(this);
          fileDialog.setAcceptMode(QFileDialog::AcceptOpen);
          fileDialog.setWindowTitle(tr("Open Files"));
          QStringList supportedMimeTypes = player->supportedMimeTypes();
          if (!supportedMimeTypes.isEmpty()) {
              supportedMimeTypes.append("audio/x-m3u"); // MP3 playlists
              fileDialog.setMimeTypeFilters(supportedMimeTypes);
          }
          fileDialog.setDirectory(QStandardPaths::standardLocations(QStandardPaths::MoviesLocation).value(0, QDir::homePath()));
          if (fileDialog.exec() == QDialog::Accepted)
              addToPlaylist(fileDialog.selectedUrls());
      }

      static bool isPlaylist(const QUrl &url) // Check for ".m3u" playlists.
      {
          if (!url.isLocalFile())
              return false;
          const QFileInfo fileInfo(url.toLocalFile());
          return fileInfo.exists() && !fileInfo.suffix().compare(QLatin1String("m3u"), Qt::CaseInsensitive);
      }

      void Player::addToPlaylist(const QList<QUrl> urls)
      {
          foreach (const QUrl &url, urls) {
              if (isPlaylist(url))
                  playlist->load(url);
              else
                  playlist->addMedia(url);
          }
      }

      void Player::durationChanged(qint64 duration)
      {
          this->duration = duration/1000;
          slider->setMaximum(duration / 1000);
      }

      void Player::positionChanged(qint64 progress)
      {
          if (!slider->isSliderDown()) {
              slider->setValue(progress / 1000);
          }
          updateDurationInfo(progress / 1000);
      }

      void Player::metaDataChanged()
      {
          if (player->isMetaDataAvailable()) {
              setTrackInfo(QString("%1 - %2")
                      .arg(player->metaData(QMediaMetaData::AlbumArtist).toString())
                      .arg(player->metaData(QMediaMetaData::Title).toString()));

              if (coverLabel) {
                  QUrl url = player->metaData(QMediaMetaData::CoverArtUrlLarge).value<QUrl>();

                  coverLabel->setPixmap(!url.isEmpty()
                          ? QPixmap(url.toString())
                          : QPixmap());
              }
          }
      }

      void Player::previousClicked()
      {
          // Go to previous track if we are within the first 5 seconds of playback
          // Otherwise, seek to the beginning.
          if(player->position() <= 5000)
              playlist->previous();
          else
              player->setPosition(0);
      }

      void Player::jump(const QModelIndex &index)
      {
          if (index.isValid()) {
              playlist->setCurrentIndex(index.row());
              player->play();
          }
      }

      void Player::playlistPositionChanged(int currentItem)
      {
          clearHistogram();
          playlistView->setCurrentIndex(playlistModel->index(currentItem, 0));
      }

      void Player::seek(int seconds)
      {
          player->setPosition(seconds * 1000);
      }

      void Player::statusChanged(QMediaPlayer::MediaStatus status)
      {
          handleCursor(status);

          // handle status message
          switch (status) {
          case QMediaPlayer::UnknownMediaStatus:
          case QMediaPlayer::NoMedia:
          case QMediaPlayer::LoadedMedia:
          case QMediaPlayer::BufferingMedia:
          case QMediaPlayer::BufferedMedia:
              setStatusInfo(QString());
              break;
          case QMediaPlayer::LoadingMedia:
              setStatusInfo(tr("Loading..."));
              break;
          case QMediaPlayer::StalledMedia:
              setStatusInfo(tr("Media Stalled"));
              break;
          case QMediaPlayer::EndOfMedia:
              QApplication::alert(this);
              break;
          case QMediaPlayer::InvalidMedia:
              displayErrorMessage();
              break;
          }
      }

      void Player::stateChanged(QMediaPlayer::State state)
      {
          if (state == QMediaPlayer::StoppedState)
              clearHistogram();
      }

      void Player::handleCursor(QMediaPlayer::MediaStatus status)
      {
      #ifndef QT_NO_CURSOR
          if (status == QMediaPlayer::LoadingMedia ||
              status == QMediaPlayer::BufferingMedia ||
              status == QMediaPlayer::StalledMedia)
              setCursor(QCursor(Qt::BusyCursor));
          else
              unsetCursor();
      #endif
      }

      void Player::bufferingProgress(int progress)
      {
          setStatusInfo(tr("Buffering %4%").arg(progress));
      }

      void Player::videoAvailableChanged(bool available)
      {
          if (!available) {
              disconnect(fullScreenButton, SIGNAL(clicked(bool)),
                          videoWidget, SLOT(setFullScreen(bool)));
              disconnect(videoWidget, SIGNAL(fullScreenChanged(bool)),
                      fullScreenButton, SLOT(setChecked(bool)));
              videoWidget->setFullScreen(false);
          } else {
              connect(fullScreenButton, SIGNAL(clicked(bool)),
                      videoWidget, SLOT(setFullScreen(bool)));
              connect(videoWidget, SIGNAL(fullScreenChanged(bool)),
                      fullScreenButton, SLOT(setChecked(bool)));

              if (fullScreenButton->isChecked())
                  videoWidget->setFullScreen(true);
          }
          colorButton->setEnabled(available);
      }

      void Player::setTrackInfo(const QString &info)
      {
          trackInfo = info;
          if (!statusInfo.isEmpty())
              setWindowTitle(QString("%1 | %2").arg(trackInfo).arg(statusInfo));
          else
              setWindowTitle(trackInfo);
      }

      void Player::setStatusInfo(const QString &info)
      {
          statusInfo = info;
          if (!statusInfo.isEmpty())
              setWindowTitle(QString("%1 | %2").arg(trackInfo).arg(statusInfo));
          else
              setWindowTitle(trackInfo);
      }

      void Player::displayErrorMessage()
      {
          setStatusInfo(player->errorString());
      }

      void Player::updateDurationInfo(qint64 currentInfo)
      {
          QString tStr;
          if (currentInfo || duration) {
              QTime currentTime((currentInfo/3600)%60, (currentInfo/60)%60, currentInfo%60, (currentInfo*1000)%1000);
              QTime totalTime((duration/3600)%60, (duration/60)%60, duration%60, (duration*1000)%1000);
              QString format = "mm:ss";
              if (duration > 3600)
                  format = "hh:mm:ss";
              tStr = currentTime.toString(format) + " / " + totalTime.toString(format);
          }
          labelDuration->setText(tStr);
      }

      void Player::showColorDialog()
      {
          if (!colorDialog) {
              QSlider *brightnessSlider = new QSlider(Qt::Horizontal);
              brightnessSlider->setRange(-100, 100);
              brightnessSlider->setValue(videoWidget->brightness());
              connect(brightnessSlider, SIGNAL(sliderMoved(int)), videoWidget, SLOT(setBrightness(int)));
              connect(videoWidget, SIGNAL(brightnessChanged(int)), brightnessSlider, SLOT(setValue(int)));

              QSlider *contrastSlider = new QSlider(Qt::Horizontal);
              contrastSlider->setRange(-100, 100);
              contrastSlider->setValue(videoWidget->contrast());
              connect(contrastSlider, SIGNAL(sliderMoved(int)), videoWidget, SLOT(setContrast(int)));
              connect(videoWidget, SIGNAL(contrastChanged(int)), contrastSlider, SLOT(setValue(int)));

              QSlider *hueSlider = new QSlider(Qt::Horizontal);
              hueSlider->setRange(-100, 100);
              hueSlider->setValue(videoWidget->hue());
              connect(hueSlider, SIGNAL(sliderMoved(int)), videoWidget, SLOT(setHue(int)));
              connect(videoWidget, SIGNAL(hueChanged(int)), hueSlider, SLOT(setValue(int)));

              QSlider *saturationSlider = new QSlider(Qt::Horizontal);
              saturationSlider->setRange(-100, 100);
              saturationSlider->setValue(videoWidget->saturation());
              connect(saturationSlider, SIGNAL(sliderMoved(int)), videoWidget, SLOT(setSaturation(int)));
              connect(videoWidget, SIGNAL(saturationChanged(int)), saturationSlider, SLOT(setValue(int)));

              QFormLayout *layout = new QFormLayout;
              layout->addRow(tr("Brightness"), brightnessSlider);
              layout->addRow(tr("Contrast"), contrastSlider);
              layout->addRow(tr("Hue"), hueSlider);
              layout->addRow(tr("Saturation"), saturationSlider);

              QPushButton *button = new QPushButton(tr("Close"));
              layout->addRow(button);

              colorDialog = new QDialog(this);
              colorDialog->setWindowTitle(tr("Color Options"));
              colorDialog->setLayout(layout);

              connect(button, SIGNAL(clicked()), colorDialog, SLOT(close()));
          }
          colorDialog->show();
      }

      void Player::clearHistogram()
      {
          QMetaObject::invokeMethod(videoHistogram, "processFrame", Qt::QueuedConnection, Q_ARG(QVideoFrame, QVideoFrame()));
          QMetaObject::invokeMethod(audioHistogram, "processBuffer", Qt::QueuedConnection, Q_ARG(QAudioBuffer, QAudioBuffer()));
      }