QT下使用ffmpeg播放视频范例

main.cpp

#include "frmmain.h"
#include 
#include 
#include 
#include 

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);   

    //根据不同QT版本编译,在QT5以下版本中需要设置为UTF-8编码才能正常显示中文
#if (QT_VERSION <= QT_VERSION_CHECK(5,0,0))
    QTextCodec *codec=QTextCodec::codecForName("UTF-8");
    QTextCodec::setCodecForLocale(codec);
    QTextCodec::setCodecForCStrings(codec);
    QTextCodec::setCodecForTr(codec);
#endif

    //加载和应用黑灰色主题样式表
    QFile qssFile(":/style.qss");
    qssFile.open(QFile::ReadOnly);
    if(qssFile.isOpen()){
        qApp->setStyleSheet(QLatin1String(qssFile.readAll()));
        qssFile.close();
    }

    frmMain w;
    //设置窗体居中显示,并且不能改变大小
    QDesktopWidget desktop;
    int screenX=desktop.availableGeometry().width();
    int screenY=desktop.availableGeometry().height();
    int frmX=w.width();
    int frmY=w.height();
    QPoint movePoint(screenX/2-frmX/2,screenY/2-frmY/2);
    w.move(movePoint);
    //设置窗体不能调整大小
    w.setFixedSize(frmX,frmY);
    w.show();

    return a.exec();
}

frmmain.cpp

#include "frmmain.h"
#include "ui_frmmain.h"
#include "qffmpeg.h"
#include "rtspthread.h"
#include 
frmMain::frmMain(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::frmMain)
{
    ui->setupUi(this);    

    tempWidth=320;
    tempHeight=180;
    video1Max=false;
    video2Max=false;
    video3Max=false;
    all=false;
    ui->labVideo1->installEventFilter(this);
    ui->labVideo2->installEventFilter(this);
    ui->labVideo3->installEventFilter(this);
}

frmMain::~frmMain()
{
    delete ui;
}

//处理用户双击对应通道最大化处理
bool frmMain::eventFilter(QObject *obj, QEvent *event)
{    
    if (event->type()==QEvent::MouseButtonDblClick){
        if (obj==ui->labVideo1){
            if (video1Max){
                tempWidth=320;
                tempHeight=180;
                ui->labVideo2->setVisible(true);
                ui->labVideo3->setVisible(true);
                ui->labImage->setVisible(true);
            }else{
                tempWidth=645;
                tempHeight=370;
                ui->labVideo2->setVisible(false);
                ui->labVideo3->setVisible(false);
                ui->labImage->setVisible(false);
            }
            video1Max=!video1Max;
        }else if (obj==ui->labVideo2){
            if (video2Max){
                tempWidth=320;
                tempHeight=180;
                ui->labVideo1->setVisible(true);
                ui->labVideo3->setVisible(true);
                ui->labImage->setVisible(true);
            }else{
                tempWidth=645;
                tempHeight=370;
                ui->labVideo1->setVisible(false);
                ui->labVideo3->setVisible(false);
                ui->labImage->setVisible(false);
            }
            video2Max=!video2Max;
        }else if (obj==ui->labVideo3){
            if (video3Max){
                tempWidth=320;
                tempHeight=180;
                ui->labVideo1->setVisible(true);
                ui->labVideo2->setVisible(true);
                ui->labImage->setVisible(true);
            }else{
                tempWidth=645;
                tempHeight=370;
                ui->labVideo1->setVisible(false);
                ui->labVideo2->setVisible(false);
                ui->labImage->setVisible(false);
            }
            video3Max=!video3Max;
        }
    }
    return QObject::eventFilter(obj,event);
}

void frmMain::on_btnOpen_clicked()
{    
    QFFmpeg *ffmpeg=new QFFmpeg(this);
    connect(ffmpeg,SIGNAL(GetImage(QImage)),this,SLOT(SetImage(QImage)));
    ffmpeg->SetUrl(ui->txtUrl->text());

    if (ffmpeg->Init()){
        RtspThread *rtsp=new RtspThread(this);
        rtsp->setffmpeg(ffmpeg);
        rtsp->start();
    }
}

void frmMain::on_btnGetImage_clicked()
{
    ui->labImage->clear();
    int index=ui->cboxVideo->currentIndex();
    if (index==0){
        if (ui->labVideo1->pixmap()!=0x0)
            ui->labImage->setPixmap(*ui->labVideo1->pixmap());
    }else if (index==1){
        if (ui->labVideo2->pixmap()!=0x0)
            ui->labImage->setPixmap(*ui->labVideo2->pixmap());
    }else if (index==2){
        if (ui->labVideo3->pixmap()!=0x0)
            ui->labImage->setPixmap(*ui->labVideo3->pixmap());
    }
}

void frmMain::SetImage(const QImage &image)
{
    if (image.height()>0){
        QPixmap pix = QPixmap::fromImage(image.scaled(tempWidth,tempHeight));
        ui->labVideo1->setPixmap(pix);
        if (all){//启用三通道同步
            ui->labVideo2->setPixmap(pix);
            ui->labVideo3->setPixmap(pix);
        }
    }
}

void frmMain::on_ckAll_stateChanged(int arg1)
{
    all=arg1!=0?true:false;
}

frmmain.h

#ifndef FRMMAIN_H
#define FRMMAIN_H

#include 

namespace Ui {
class frmMain;
}

class frmMain : public QWidget
{
    Q_OBJECT

public:
    explicit frmMain(QWidget *parent = 0);
    ~frmMain();

private slots:
    void SetImage(const QImage &image);
    void on_btnOpen_clicked();
    void on_btnGetImage_clicked();

    void on_ckAll_stateChanged(int arg1);

protected:
    bool eventFilter(QObject *obj, QEvent *event);

private:
    Ui::frmMain *ui;

    int tempWidth;
    int tempHeight;
    bool video1Max;
    bool video2Max;
    bool video3Max;
    bool all;    
};

#endif // FRMMAIN_H

qffmeg.cpp

#include "qffmpeg.h"
#include 
#include 

QFFmpeg::QFFmpeg(QObject *parent) :
    QObject(parent)
{    
    videoStreamIndex=-1;
    av_register_all();//注册库中所有可用的文件格式和解码器
    avformat_network_init();//初始化网络流格式,使用RTSP网络流时必须先执行
    pAVFormatContext = avformat_alloc_context();//申请一个AVFormatContext结构的内存,并进行简单初始化
    pAVFrame=av_frame_alloc();
}

QFFmpeg::~QFFmpeg()
{
    avformat_free_context(pAVFormatContext);
    av_frame_free(&pAVFrame);
    sws_freeContext(pSwsContext);
}

bool QFFmpeg::Init()
{
    //打开视频流
    int result=avformat_open_input(&pAVFormatContext, url.toStdString().c_str(),NULL,NULL);
    if (result<0){
        qDebug()<<"打开视频流失败";
        return false;
    }

    //获取视频流信息
    result=avformat_find_stream_info(pAVFormatContext,NULL);
    if (result<0){
        qDebug()<<"获取视频流信息失败";
        return false;
    }

    //获取视频流索引
    videoStreamIndex = -1;
    for (uint i = 0; i < pAVFormatContext->nb_streams; i++) {
        if (pAVFormatContext->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
            videoStreamIndex = i;
            break;
        }
    }

    if (videoStreamIndex==-1){
        qDebug()<<"获取视频流索引失败";
        return false;
    }

    //获取视频流的分辨率大小
    pAVCodecContext = pAVFormatContext->streams[videoStreamIndex]->codec;
    videoWidth=pAVCodecContext->width;
    videoHeight=pAVCodecContext->height;

    avpicture_alloc(&pAVPicture,PIX_FMT_RGB24,videoWidth,videoHeight);

    AVCodec *pAVCodec;

    //获取视频流解码器
    pAVCodec = avcodec_find_decoder(pAVCodecContext->codec_id);
    pSwsContext = sws_getContext(videoWidth,videoHeight,PIX_FMT_YUV420P,videoWidth,videoHeight,PIX_FMT_RGB24,SWS_BICUBIC,0,0,0);

    //打开对应解码器
    result=avcodec_open2(pAVCodecContext,pAVCodec,NULL);
    if (result<0){
        qDebug()<<"打开解码器失败";
        return false;
    }

    qDebug()<<"初始化视频流成功";
    return true;
}

void QFFmpeg::Play()
{
    //一帧一帧读取视频
    int frameFinished=0;
    while (true){
        if (av_read_frame(pAVFormatContext, &pAVPacket) >= 0){
            if(pAVPacket.stream_index==videoStreamIndex){
                qDebug()<<"开始解码"<data,pAVFrame->linesize,0,videoHeight,pAVPicture.data,pAVPicture.linesize);
                    //发送获取一帧图像信号
                    QImage image(pAVPicture.data[0],videoWidth,videoHeight,QImage::Format_RGB888);
                    emit GetImage(image);
                    mutex.unlock();
                }
            }
        }
        av_free_packet(&pAVPacket);//释放资源,否则内存会一直上升
    }
}

qffmpeg.h

#ifndef QFFMPEG_H
#define QFFMPEG_H

//必须加以下内容,否则编译不能通过,为了兼容C和C99标准
#ifndef INT64_C
#define INT64_C
#define UINT64_C
#endif

//引入ffmpeg头文件
extern "C"
{
#include 
#include 
#include 
#include 
#include 
}

#include 
#include 
#include 

class QFFmpeg : public QObject
{
    Q_OBJECT
public:
    explicit QFFmpeg(QObject *parent = 0);
    ~QFFmpeg();

    bool Init();
    void Play();

    void SetUrl(QString url){this->url=url;}
    QString Url()const{return url;}
    int VideoWidth()const{return videoWidth;}
    int VideoHeight()const{return videoHeight;}

private:
    QMutex mutex;
    AVPicture  pAVPicture;
    AVFormatContext *pAVFormatContext;
    AVCodecContext *pAVCodecContext;
    AVFrame *pAVFrame;
    SwsContext * pSwsContext;
    AVPacket pAVPacket;

    QString url;
    int videoWidth;
    int videoHeight;
    int videoStreamIndex;

signals:
    void GetImage(const QImage &image);

public slots:

};

#endif // QFFMPEG_H

rtspthread.cpp

#include "rtspthread.h"

RtspThread::RtspThread(QObject *parent) :
    QThread(parent)
{
}

void  RtspThread::run()
{    
    ffmpeg->Play();
}

rtspthread.h

#ifndef RTSPTHREAD_H
#define RTSPTHREAD_H

#include 
#include "qffmpeg.h"

class RtspThread : public QThread
{
    Q_OBJECT
public:
    explicit RtspThread(QObject *parent = 0);

    void run();    
    void setffmpeg(QFFmpeg *f){ffmpeg=f;}

private:    
    QFFmpeg * ffmpeg;

signals:

public slots:

};

#endif // RTSPTHREAD_H

源代码加库文件：https://download.csdn.net/download/gaodes/10769146

搭配使用的live555服务器：https://download.csdn.net/download/gaodes/10769151