在上一节中,我们讲解了如何使用QWidget渲染每一帧视频数据。
由于我们不停的生成的是QImage对象,因此对 CPU 负荷较高。其实在绘制这块我们可以使用 OpenGL去绘制,利用 GPU 减轻 CPU 计算负荷,本节讲解使用OpenGL来绘制每一帧视频数据。
libVLC 提取视频帧使用QWidget渲染-CSDN博客
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.提取视频帧数据,回调给OpenGL显示。
static void unlock(void *opaque, void *picture, void *const *planes) {// 这里可以释放视频帧的锁uint8_t *buffer = (uint8_t *)*planes; //planes即为帧数据//QImage image((unsigned char*)buffer, g_frame->width, g_frame->height, QImage::Format_ARGB32);m_this->m_videoFunc(buffer);g_frame->mutex.unlock();
}
声明了两个OpenGL接口回调。
//视频每一帧数据回调
typedef std::function<void(uint8_t*)> VideoDataFunc;
//视频宽、高。回调
typedef std::function<void(int, int)> VideoInfoFunc;
设置回调。
//视频数据m_videoFunc = std::bind(&WOpenGLWidget::slotReceiveVideoData, ui.openGLWidget,std::placeholders::_1);//视频信息m_videoInfoFunc = std::bind(&WOpenGLWidget::slotOpenVideo, ui.openGLWidget,std::placeholders::_1, std::placeholders::_2);
使用回调。
static void unlock(void *opaque, void *picture, void *const *planes) {// 这里可以释放视频帧的锁uint8_t *buffer = (uint8_t *)*planes; //planes即为帧数据//QImage image((unsigned char*)buffer, g_frame->width, g_frame->height, QImage::Format_ARGB32);m_this->m_videoFunc(buffer);g_frame->mutex.unlock();
}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;m_this->m_videoInfoFunc(w, h);return 1;
}
opengl完全没有基础的同学,请先学习以下的几篇文章,我们只需要了解2D图像如何渲染就行。
1.OpenGL简介
2.OpenGL实现第一个窗口-三角形
3.OpenGL 纹理
首先继承QOpenGLWidget类,重写paintGL()、resizeGL()、initializeGL()方法。
本示例演示使用opengles2来渲染,渲染rgba的数据。
以下是封装好的WOpenGLWidget类,使用提升的方式,提升为以下这个类就行了。
#ifndef WOPENGLWIDGET_H
#define WOPENGLWIDGET_H#include <QOpenGLWidget>
#include <QOpenGLFunctions>
#include <QOpenGLTexture>
#include <QImage>
#include <QOpenGLShaderProgram>
#include <QOpenGLShader>
#include <QDebug>
#include <QImage>
#include <QMouseEvent>
#include <QSet>
#include <QPainter>
#include <QMutex>
#include <QOpenGLBuffer>class OpenGLDisplayImpl
{
public:OpenGLDisplayImpl(){texture = NULL;videoW = 0;videoH = 0;}unsigned char *buffer = {0};QOpenGLTexture* texture;GLsizei videoW, videoH;
};class WOpenGLWidget : public QOpenGLWidget,public QOpenGLFunctions
{Q_OBJECT
public:WOpenGLWidget(QWidget* parent = Q_NULLPTR);~WOpenGLWidget();public:void slotOpenVideo(int width,int height);void slotReceiveVideoData(uint8_t* buffer);void clear();void deleteBuffer();protected:virtual void initializeGL();virtual void paintGL();virtual void resizeGL(int w, int h);private:QOpenGLShaderProgram *m_program = nullptr; //着色器程序QOpenGLBuffer VBO, EBO;OpenGLDisplayImpl *m_impl = nullptr;bool m_isShowVideo = false;QMutex m_mux;
};#endif // WOPENGLWIDGET_H#include "WOpenGLWidget.h"
#include <QDebug>
#include <QTimer>
#include <QElapsedTimer>static float vertices[] = {
// ---- 位置 ---- - 纹理坐标 -1.0f, 1.0f, 0.0f, 1.0f, 1.0f, // 右上1.0f, -1.0f, 0.0f, 1.0f, 0.0f, // 右下-1.0f, -1.0f, 0.0f, 0.0f, 0.0f, // 左下-1.0f, 1.0f, 0.0f, 0.0f, 1.0f // 左上
};static unsigned int indices[] = {0, 1, 3,1, 2, 3
};WOpenGLWidget::WOpenGLWidget(QWidget* parent): QOpenGLWidget(parent), m_impl(new OpenGLDisplayImpl), EBO(QOpenGLBuffer::IndexBuffer)
{
}WOpenGLWidget::~WOpenGLWidget()
{clear();if (m_impl->texture){m_impl->texture->destroy();}delete m_impl;m_impl = nullptr;
}void WOpenGLWidget::slotOpenVideo(int width, int height)
{qDebug() << "slotOpenVideo";m_mux.lock();glClearColor(0.0f, 0.0f, 0.0f, 0.0f);glClear(GL_COLOR_BUFFER_BIT);m_isShowVideo = false;m_impl->videoW = width;m_impl->videoH = height;deleteBuffer();resize(this->width(), this->height());m_isShowVideo = true;m_mux.unlock();
}void WOpenGLWidget::slotReceiveVideoData(uint8_t* yuvBuffer)
{if (!m_impl)return;m_mux.lock();if(!m_impl->buffer)m_impl->buffer = new unsigned char[m_impl->videoW * m_impl->videoH * 4];//ymemcpy(m_impl->buffer, yuvBuffer, m_impl->videoW * m_impl->videoH * 4);update();m_mux.unlock();
}void WOpenGLWidget::clear()
{m_mux.lock();deleteBuffer();m_isShowVideo = false;m_mux.unlock();
}void WOpenGLWidget::deleteBuffer()
{if (m_impl){if (m_impl->buffer) {delete m_impl->buffer;m_impl->buffer= nullptr;}}
}void WOpenGLWidget::initializeGL()
{m_mux.lock();initializeOpenGLFunctions();m_program = new QOpenGLShaderProgram();m_program->addShaderFromSourceFile(QOpenGLShader::Vertex,":/shaders/shaders/shapes.vert");m_program->addShaderFromSourceFile(QOpenGLShader::Fragment,":/shaders/shaders/shapes.frag");bool success = m_program->link();if (!success)qDebug() << "ERR:" << m_program->log();VBO.create();EBO.create();VBO.bind();EBO.bind();VBO.allocate(vertices, 20 * sizeof(float));EBO.allocate(indices, 6 * sizeof(unsigned int));m_impl->texture = new QOpenGLTexture(QOpenGLTexture::Target2D);m_impl->texture->create();m_impl->texture->setMinificationFilter(QOpenGLTexture::Nearest);m_impl->texture->setMinificationFilter(QOpenGLTexture::Linear);m_impl->texture->setWrapMode(QOpenGLTexture::ClampToEdge);m_mux.unlock();// 启动定时器QTimer *ti = new QTimer(this);connect(ti, &QTimer::timeout, this, [=] {update();});ti->start(100);
}void WOpenGLWidget::paintGL()
{glClearColor(0.2f, 0.3f, 0.3f, 1.0f);glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);m_mux.lock();if (m_isShowVideo){ VBO.bind();EBO.bind();m_program->bind();m_impl->texture->bind(0);m_program->setUniformValue("texture", 0);int vertexLocation = m_program->attributeLocation("position");m_program->enableAttributeArray(vertexLocation);m_program->setAttributeBuffer(vertexLocation, GL_FLOAT, 0, 3, 5 * sizeof(float));int texcoordLocation = m_program->attributeLocation("texCoord");m_program->enableAttributeArray(texcoordLocation);m_program->setAttributeBuffer(texcoordLocation, GL_FLOAT, 3 * sizeof(float), 2, 5 * sizeof(float));//激活纹理单元0glActiveTexture(GL_TEXTURE0);glBindTexture(GL_TEXTURE_2D, m_impl->texture->textureId());glPixelStorei(GL_UNPACK_ALIGNMENT, 1);glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, m_impl->videoW,m_impl->videoH, 0, GL_BGRA, GL_UNSIGNED_BYTE, m_impl->buffer);//设置纹理环绕方式glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);glDrawElements(GL_TRIANGLES,6, GL_UNSIGNED_INT,0);if(m_impl->texture)m_impl->texture->release();m_program->release();}m_mux.unlock();
}void WOpenGLWidget::resizeGL(int w, int h)
{// 设置视口//glViewport(0, 0, w, h);
}
着色器如下所示。
//shapes.vert#ifdef GL_ES
precision mediump int;
precision mediump float;
#endifattribute vec3 position;
attribute vec2 texCoord;varying vec2 outTexCoord;void main()
{gl_Position = vec4(position,1.0);outTexCoord = vec2(texCoord.x, 1.0 - texCoord.y);
}//shapes.frag#ifdef GL_ES
// Set default precision to medium
precision mediump int;
precision mediump float;
#endifuniform sampler2D texture;varying vec2 outTexCoord;void main()
{vec3 rgb = texture2D(texture, outTexCoord);gl_FragColor = vec4(rgb, 1);
}
ui界面如下图所示。
运行截图:
完整代码:
#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>//视频每一帧数据回调
typedef std::function<void(uint8_t*)> VideoDataFunc;
//视频宽、高。回调
typedef std::function<void(int, int)> VideoInfoFunc;enum Rate
{Rate2X,Rate1_5X,Rate1_25X,Rate1_0X,Rate0_75X,Rate0_5X
};class showWidget : public QWidget
{Q_OBJECTpublic:showWidget(QWidget *parent = nullptr);~showWidget();public:VideoDataFunc m_videoFunc;VideoInfoFunc m_videoInfoFunc;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;QList<float> m_lstRate;QList<QString> m_lstAudioDevice;
};//=====================================================#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uint8_t *buffer = (uint8_t *)*planes; //planes即为帧数据//QImage image((unsigned char*)buffer, g_frame->width, g_frame->height, QImage::Format_ARGB32);m_this->m_videoFunc(buffer);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;m_this->m_videoInfoFunc(w, 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);//视频数据m_videoFunc = std::bind(&WOpenGLWidget::slotReceiveVideoData, ui.openGLWidget,std::placeholders::_1);//视频信息m_videoInfoFunc = std::bind(&WOpenGLWidget::slotOpenVideo, ui.openGLWidget,std::placeholders::_1, std::placeholders::_2);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::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:
Qt+FFmpeg+opengl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
Qt+FFmpeg+opengl从零制作视频播放器-1.项目介绍_qt opengl视频播放器-CSDN博客
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