简介

使用QT的QMediaPlayer类播放MP4格式的视频。

代码示例

头文件

Ui::MainWindow *ui;
QMediaPlaylist *playlist;
QMediaPlayer *player;
QVideoWidget *videoWidget;

方式一

应用窗体外播放视频。

.cpp文件

 playlist = new QMediaPlaylist;playlist->addMedia(QUrl("qrc:/video/sample5s.mp4"));playlist->addMedia(QUrl("qrc:/video/SampleVideo1mb.mp4"));playlist->setCurrentIndex(0);player = new QMediaPlayer;player->setPlaylist(playlist);videoWidget = new QVideoWidget;videoWidget->setFixedSize(1366,768); //设置video窗体大小videoWidget->setWindowFlag(Qt::FramelessWindowHint); //设置无边框player->setVideoOutput(videoWidget);videoWidget->show();player->play();

效果如下

在这里插入图片描述

方式二

UI设计器界面拖拽一个Widget，右键提升为QVideoWidget，窗体内播放视频；

.cpp文件

player = new QMediaPlayer;
playlist = new QMediaPlaylist(player);playlist->addMedia(QUrl("qrc:/video/sample5s.mp4"));
playlist->addMedia(QUrl("qrc:/video/SampleVideo1mb.mp4"));
playlist->setCurrentIndex(0);
playlist->setPlaybackMode(QMediaPlaylist::Loop);//循环播放
player->setPlaylist(playlist);ui->videowidget->setAspectRatioMode(Qt::IgnoreAspectRatio);//自适应铺满界面
//ui->videowidget->setFullScreen(true);  //全屏
player->setVideoOutput(ui->videowidget);
player->play();

效果如下**

在这里插入图片描述

QMediaPlayer播放视频常见信号处理

常用信号及其绑定

//播放进度
connect(player,&QMediaPlayer::positionChanged,this,&MainWindow::updatePosition);//媒体状态
connect(player, &QMediaPlayer::mediaStatusChanged, this, &MainWindow::mediaStatusChanged);//播放错误状态捕获
connect(player, static_cast<void(QMediaPlayer::*)(QMediaPlayer::Error)>(&QMediaPlayer::error), this, &MainWindow::showError);//播放状态
connect(player, &QMediaPlayer::stateChanged, this, &MainWindow::stateChanged);//获取元数据
connect(player, &QMediaPlayer::metaDataAvailableChanged,this, &MainWindow::metaDataAvailableChanged);

对应槽函数处理方法

//position 为当前播放时长，不播放则为0
//player->duration() 为视频的总时长，但当视频还没有加载完成时返回为0
void MainWindow::updatePosition(qint64 position)
{if(position > 0){ui->videowidget->setVisible(true);}//不使用QMediaPlaylist时，实现循环播放if(position == player->duration()){if(player->duration() != 0){player->play();}}
}void MainWindow::mediaStatusChanged(QMediaPlayer::MediaStatus status)
{switch (status) {case QMediaPlayer::UnknownMediaStatus:ui->label->setText(tr("媒体未知状况！"));break;case QMediaPlayer::NoMedia:ui->label->setText(tr("没有媒体文件！"));break;case QMediaPlayer::BufferingMedia:ui->label->setText(tr("正在缓冲媒体文件！"));break;case QMediaPlayer::BufferedMedia:ui->label->setText(tr("媒体文件缓冲完成！"));break;case QMediaPlayer::LoadingMedia:ui->label->setText(tr("正在加载媒体！"));break;case QMediaPlayer::StalledMedia:ui->label->setText(tr("播放停滞！"));break;case QMediaPlayer::EndOfMedia:ui->label->setText(tr("播放结束！"));break;case QMediaPlayer::LoadedMedia:ui->label->setText(tr("媒体加载完成！"));break;case QMediaPlayer::InvalidMedia:ui->label->setText(tr("不可用的媒体文件！"));break;default: break;}
}void MainWindow::stateChanged(QMediaPlayer::State state)
{switch (state) {case QMediaPlayer::StoppedState:ui->label_2->setText(tr("停止状态！"));break;case QMediaPlayer::PlayingState:ui->label_2->setText(tr("播放状态！"));break;case QMediaPlayer::PausedState:ui->label_2->setText(tr("暂停状态！"));break;default: break;}
}void MainWindow::showError(QMediaPlayer::Error error)
{switch (error) {case QMediaPlayer::NoError:ui->label_3->setText(tr("没有错误！"));break;case QMediaPlayer::ResourceError:ui->label_3->setText(tr("媒体资源无法被解析！"));break;case QMediaPlayer::FormatError:ui->label_3->setText(tr("不支持该媒体格式！"));break;case QMediaPlayer::NetworkError:ui->label_3->setText(tr("发生了一个网络错误！"));break;case QMediaPlayer::AccessDeniedError:ui->label_3->setText(tr("没有播放权限！"));break;case QMediaPlayer::ServiceMissingError:ui->label_3->setText(tr("没有发现有效的播放服务！"));break;default:ui->label_3->setText(tr("未知错误码！"));break;}
}// 获取元数据
void MainWindow::metaDataAvailableChanged(bool available)
{if(available){QString title = player->metaData("Title").toString();QString author = player->metaData("Author").toString();setWindowTitle(title + "-" + author);}
}