网站如何添加百度地图,网站建设商城建设,怀柔重庆网站建设,长春网站开发推荐在前面章节中#xff0c;我们讲解了如何使用QWidget渲染每一帧视频数据#xff0c;这种方法对 CPU 负荷较高。
libVLC 提取视频帧使用QWidget渲染-CSDN博客
后面又讲解了使用OpenGL渲染每一帧视频数据#xff0c;使用 OpenGL去绘制#xff0c;利用 GPU 减轻 CPU 计算负荷…在前面章节中我们讲解了如何使用QWidget渲染每一帧视频数据这种方法对 CPU 负荷较高。
libVLC 提取视频帧使用QWidget渲染-CSDN博客
后面又讲解了使用OpenGL渲染每一帧视频数据使用 OpenGL去绘制利用 GPU 减轻 CPU 计算负荷。
libVLC 提取视频帧使用OpenGL渲染-CSDN博客
本章节介绍另一种方法来渲染视频使用QGraphicsView来渲染。
以下是操作流程
1.初始化 libVLC 实例。
vlc_base libvlc_new(0, NULL);
2.创建一个媒体播放器。 vlc_media libvlc_media_new_path(vlc_base, filename.toUtf8().data());if (!vlc_media) {return;}// 创建libvlc实例和媒体播放器vlc_mediaPlayer libvlc_media_player_new_from_media(vlc_media);if (!vlc_mediaPlayer) {return;}
3.设置视频回调。 libvlc_video_set_format_callbacks(vlc_mediaPlayer, setup, NULL);// 设置自定义视频输出libvlc_video_set_callbacks(vlc_mediaPlayer, lock, unlock, display, NULL);
4.创建QGraphicsScene场景对象并设置矩形区域QGraphicsView设置场景对象然后在场景中添加一个QGraphicsItem对象用于显示视频。 void showWidget::showEvent(QShowEvent *event)
{if (m_init)return;m_init true;QRect rect this-rect();rect - QMargins(15, 15, 15, 91);m_scene new QGraphicsScene(rect, this);ui.graphicsView-setScene(m_scene);m_item new ShowGraphicsItem();m_item-setRect(rect);m_scene-addItem(m_item);
}
ShowGraphicsItem是继承QGraphicsItem类需要重写以下两个方法 virtual QRectF boundingRect() const;virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget Q_NULLPTR);
类定义如下
#pragma once
#include QGraphicsItem
#include QPainter
#include QImageclass ShowGraphicsItem : public QGraphicsItem
{
public:ShowGraphicsItem(QGraphicsItem *parent Q_NULLPTR);~ShowGraphicsItem();public:void setRect(const QRectF rect);void setImage(const QImage image);public:virtual QRectF boundingRect() const;virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget Q_NULLPTR);private:QImage m_image;QRectF m_rect;
};#include ShowGraphicsItem.hShowGraphicsItem::ShowGraphicsItem(QGraphicsItem *parent /* Q_NULLPTR*/): QGraphicsItem(parent)
{}ShowGraphicsItem::~ShowGraphicsItem()
{}void ShowGraphicsItem::setRect(const QRectF rect)
{prepareGeometryChange();m_rect rect;update();
}void ShowGraphicsItem::setImage(const QImage image)
{m_image image;update();
}QRectF ShowGraphicsItem::boundingRect() const
{return m_rect;
}void ShowGraphicsItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget /* Q_NULLPTR*/)
{painter-setRenderHint(QPainter::Antialiasing, true);painter-setRenderHint(QPainter::SmoothPixmapTransform, true);painter-setRenderHint(QPainter::TextAntialiasing, true);// 反走样painter-setRenderHint(QPainter::Antialiasing, true);painter-drawImage(this-boundingRect(), m_image);
}5.提取视频帧数据创建QImage对象传入给ShowGraphicsItem显示。
static void unlock(void *opaque, void *picture, void *const *planes) {// 这里可以释放视频帧的锁char *buffer (char *)*planes; //planes即为帧数据QImage image((unsigned char*)buffer, g_frame-width, g_frame-height, QImage::Format_ARGB32);m_this-updatePic(image);g_frame-mutex.unlock();
}void showWidget::updatePic(const QImage image)
{m_item-setImage(image);
}
这里介绍回调函数的意义请看以下链接。
libVLC 提取视频帧-CSDN博客
以下是ui界面设计 运行结果 代码示例
这里使用声明了static showWidget* m_this nullptr。在构造函数中使用m_this this赋值。在unlock回调中构造好QImage对象使用m_this-updatePic(image)更新界面。重写了void resizeEvent(QResizeEvent *event);事件使item跟随窗口大小变化而变化。
#pragma once#include QtWidgets/QWidget
#include ui_showWidget.h
#include QMenu
#include QActionGroup
#include vlc/vlc.h
#include QDebug
#include QFileDialog
#include QThread
#include QMouseEvent
#include QKeyEvent
#include QGraphicsScene
#include ShowGraphicsItem.henum Rate
{Rate2X,Rate1_5X,Rate1_25X,Rate1_0X,Rate0_75X,Rate0_5X
};class showWidget : public QWidget
{Q_OBJECTpublic:showWidget(QWidget *parent nullptr);~showWidget();public:void updatePic(const QImage image);protected:void showEvent(QShowEvent *event);void resizeEvent(QResizeEvent *event);private slots:void slotOpenFile();void slotPlay();void slotPause();void slotStop();void slotValueChanged(int value);void slotCurrentIndexChanged(int index);private://事件处理回调static void vlcEvents(const libvlc_event_t *ev, void *param);private:Ui::showWidgetClass ui;private:libvlc_instance_t *vlc_base nullptr;libvlc_media_t *vlc_media nullptr;libvlc_media_player_t *vlc_mediaPlayer nullptr;QListfloat m_lstRate;QListQString m_lstAudioDevice;QGraphicsScene *m_scene nullptr;ShowGraphicsItem *m_item nullptr;bool m_init false;
};#include showWidget.h
#include QTimer
#include QTime
#include QMutex
#include stdlib.h #pragma execution_character_set(utf-8)static showWidget* m_this nullptr;struct Frame
{int width;int height;uchar * pixels;QMutex mutex;
};static Frame *g_frame nullptr;// 自定义视频输出模块的回调函数
static void *lock(void *opaque, void **planes) {g_frame-mutex.lock();*planes g_frame-pixels;return 0;
}static void unlock(void *opaque, void *picture, void *const *planes) {// 这里可以释放视频帧的锁char *buffer (char *)*planes; //planes即为帧数据QImage image((unsigned char*)buffer, g_frame-width, g_frame-height, QImage::Format_ARGB32);m_this-updatePic(image);g_frame-mutex.unlock();
}static void display(void *opaque, void *picture) {// 这里可以进行视频帧的显示或其他处理(void)opaque;
}static unsigned setup(void **opaque, char *chroma,unsigned *width, unsigned *height,unsigned *pitches,unsigned *lines)
{qDebug() chroma: QString(chroma) width: *width , height: *height;/* 开辟存放图像数据的内存块 */if (g_frame){if (g_frame-pixels){delete[] g_frame-pixels;g_frame-pixels NULL;}delete g_frame;g_frame NULL;}int w *width;int h *height;g_frame new Frame;g_frame-pixels new uchar[w * h * 4]; // 申请大小也为4通道的像素memset(g_frame-pixels, 0, w * h * 4);memcpy(chroma, RV32, 4);g_frame-width w;g_frame-height h;*pitches w * 4;*lines h;return 1;
}showWidget::showWidget(QWidget *parent): QWidget(parent)
{ui.setupUi(this);m_this this;this-setWindowTitle(视频播放器);vlc_base libvlc_new(0, NULL);ui.cbxRate-setCurrentIndex(Rate1_0X);m_lstRate 2.0 1.5 1.25 1.0 0.75 0.5;ui.btnOpen-setFocusPolicy(Qt::NoFocus);ui.btnPlay-setFocusPolicy(Qt::NoFocus);ui.btnPause-setFocusPolicy(Qt::NoFocus);ui.btnStop-setFocusPolicy(Qt::NoFocus);ui.hSliderVolumn-setFocusPolicy(Qt::NoFocus);ui.cbxRate-setFocusPolicy(Qt::NoFocus);connect(ui.btnOpen, QPushButton::clicked, this, showWidget::slotOpenFile);connect(ui.btnPlay, QPushButton::clicked, this, showWidget::slotPlay);connect(ui.btnPause, QPushButton::clicked, this, showWidget::slotPause);connect(ui.btnStop, QPushButton::clicked, this, showWidget::slotStop);connect(ui.hSliderVolumn, QSlider::valueChanged, this, showWidget::slotValueChanged);connect(ui.cbxRate,SIGNAL(currentIndexChanged(int)), this, SLOT(slotCurrentIndexChanged(int)));
}showWidget::~showWidget()
{libvlc_release(vlc_base); //减少libvlc实例的引用计数并销毁
}void showWidget::updatePic(const QImage image)
{m_item-setImage(image);
}void showWidget::showEvent(QShowEvent *event)
{if (m_init)return;m_init true;QRect rect this-rect();rect - QMargins(15, 15, 15, 91);m_scene new QGraphicsScene(rect, this);ui.graphicsView-setScene(m_scene);m_item new ShowGraphicsItem();m_item-setRect(rect);m_scene-addItem(m_item);
}void showWidget::resizeEvent(QResizeEvent *event)
{if (!m_init)return;QRect rect this-rect();rect - QMargins(15, 15, 15, 91);m_scene-setSceneRect(rect);m_item-setRect(rect);
}void showWidget::slotOpenFile()
{/*选择文件*/QString filename QFileDialog::getOpenFileName(this, 选择打开的文件, D:/, tr(*.*));std::replace(filename.begin(), filename.end(), QChar(/), QChar(\\));vlc_media libvlc_media_new_path(vlc_base, filename.toUtf8().data());if (!vlc_media) {return;}// 创建libvlc实例和媒体播放器vlc_mediaPlayer libvlc_media_player_new_from_media(vlc_media);if (!vlc_mediaPlayer) {return;}libvlc_video_set_format_callbacks(vlc_mediaPlayer, setup, NULL);// 设置自定义视频输出libvlc_video_set_callbacks(vlc_mediaPlayer, lock, unlock, display, NULL);// 等待元数据加载完成libvlc_media_parse(vlc_media);// 获取各种元数据const char *title libvlc_media_get_meta(vlc_media, libvlc_meta_Title);const char *artist libvlc_media_get_meta(vlc_media, libvlc_meta_Artist);const char *album libvlc_media_get_meta(vlc_media, libvlc_meta_Album);const char *url libvlc_media_get_meta(vlc_media, libvlc_meta_URL);const char *date libvlc_media_get_meta(vlc_media, libvlc_meta_Date);const char *lang libvlc_media_get_meta(vlc_media, libvlc_meta_Language);int duration libvlc_media_get_duration(vlc_media); // 获取时长单位毫秒qDebug(Title: %s, title ? title : N/A);qDebug(Artist: %s, artist ? artist : N/A);qDebug(Album: %s, album ? album : N/A);qDebug(Duration: %d ms, duration);qDebug(url: %s, url ? url : N/A);qDebug(date: %s, date ? date : N/A);qDebug(lang: %s, lang ? lang : N/A);libvlc_media_track_t **tracks;int track_count libvlc_media_tracks_get(vlc_media,tracks);for (unsigned i 0; i track_count; i) {libvlc_media_track_t* track tracks[i];// 显示轨道信息printf(Track #%u: %s\n, i, track-psz_description);// 这里可以获取到每一个轨道的信息比如轨道类型 track-i_type// 可能是 libvlc_track_video, libvlc_track_audio 或者 libvlc_track_text (字幕)if (track-i_type libvlc_track_video) {// 处理视频轨道信息qDebug(width %d,track-video-i_width);qDebug(height %d, track-video-i_height);qDebug(rate_num %d, track-video-i_frame_rate_num);qDebug(rate_den %d, track-video-i_frame_rate_den);}else if (track-i_type libvlc_track_audio) {// 处理音频轨道信息qDebug(channels %d, track-audio-i_channels);qDebug(rate %d, track-audio-i_rate);}else if (track-i_type libvlc_track_text) {// 处理字幕轨道信息}}//获取事件管理器libvlc_event_manager_t *em libvlc_media_player_event_manager(vlc_mediaPlayer);// 注册事件监听器libvlc_event_attach(em, libvlc_MediaPlayerTimeChanged, vlcEvents, this);libvlc_event_attach(em, libvlc_MediaPlayerEndReached, vlcEvents, this);libvlc_event_attach(em, libvlc_MediaPlayerStopped, vlcEvents, this);libvlc_event_attach(em, libvlc_MediaPlayerPlaying, vlcEvents, this);libvlc_event_attach(em, libvlc_MediaPlayerPaused, vlcEvents, this);QTimer::singleShot(1000, this, showWidget::slotPlay);libvlc_video_filter_list_get(vlc_base);
}void showWidget::slotPlay()
{if (vlc_mediaPlayer){libvlc_media_player_play(vlc_mediaPlayer);}
}void showWidget::slotPause()
{if (vlc_mediaPlayer)libvlc_media_player_pause(vlc_mediaPlayer);
}void showWidget::slotStop()
{if (vlc_mediaPlayer)libvlc_media_player_stop(vlc_mediaPlayer);
}void showWidget::slotValueChanged(int value)
{if (vlc_mediaPlayer)libvlc_audio_set_volume(vlc_mediaPlayer, value);
}void showWidget::slotCurrentIndexChanged(int index)
{if (vlc_mediaPlayer)libvlc_media_player_set_rate(vlc_mediaPlayer, m_lstRate[index]);
}//事件回调
void showWidget::vlcEvents(const libvlc_event_t *ev, void *param)
{showWidget *w (showWidget*)param;//处理不同的事件switch (ev-type) {case libvlc_MediaPlayerTimeChanged:{//qDebug() VLC媒体播放器时间已更改;qint64 len libvlc_media_player_get_time(w-vlc_mediaPlayer);libvlc_time_t lenSec len / 1000;libvlc_time_t totalLen libvlc_media_player_get_length(w-vlc_mediaPlayer);libvlc_time_t totalLenSec totalLen / 1000;int thh, tmm, tss;thh lenSec / 3600;tmm (lenSec % 3600) / 60;tss (lenSec % 60);QTime time(thh, tmm, tss);w-ui.lbCurTime-setText(time.toString(hh:mm:ss));thh totalLenSec / 3600;tmm (totalLenSec % 3600) / 60;tss (totalLenSec % 60);QTime TotalTime(thh, tmm, tss);w-ui.lbTotalTime-setText(TotalTime.toString(hh:mm:ss));double pos (double)lenSec / totalLenSec * 100;w-ui.horizontalSlider-setValue(pos);}break;case libvlc_MediaPlayerEndReached:qDebug() VLC播放完毕.;break;case libvlc_MediaPlayerStopped:qDebug() VLC停止播放;break;case libvlc_MediaPlayerPlaying:qDebug() VLC开始播放;break;case libvlc_MediaPlayerPaused:qDebug() VLC暂停播放;break;}
} 更多参考
libVLC 添加图片和文本水印-CSDN博客
libVLC 音频输出设备切换-CSDN博客
libVLC 音频立体声模式切换-CSDN博客
QT Graphics View_qtgraphicsview-CSDN博客
QtFFmpegopengl从零制作视频播放器-7.OpenGL播放视频_qt opengl视频播放器-CSDN博客
QtFFmpegopengl从零制作视频播放器-1.项目介绍_qt opengl视频播放器-CSDN博客
