include_directories(${CMAKE_SOURCE_DIR}/lib/ffmpeg/include)
 
target_link_libraries(QtFFmpegApp1 PRIVATE ${CMAKE_SOURCE_DIR}/lib/ffmpeg/lib/avcodec.lib
                                           ${CMAKE_SOURCE_DIR}/lib/ffmpeg/lib/avdevice.lib
                                           ${CMAKE_SOURCE_DIR}/lib/ffmpeg/lib/avfilter.lib
                                           ${CMAKE_SOURCE_DIR}/lib/ffmpeg/lib/avformat.lib
                                           ${CMAKE_SOURCE_DIR}/lib/ffmpeg/lib/avutil.lib
                                           ${CMAKE_SOURCE_DIR}/lib/ffmpeg/lib/postproc.lib
                                          ${CMAKE_SOURCE_DIR}/lib/ffmpeg/lib/swresample.lib
                                           ${CMAKE_SOURCE_DIR}/lib/ffmpeg/lib/swscale.lib
                                       )

extern "C"
{
#include "libavformat/avformat.h"
#include "libavformat/avio.h"
#include "libavcodec/avcodec.h"
#include "libavutil/buffer.h"
#include "libavutil/error.h"
#include "libavutil/mem.h"
#include "libavutil/imgutils.h"
#include <libswscale/swscale.h>
#include <libavutil/imgutils.h>
#include <libavfilter/avfilter.h>
}

std::string s = avcodec_configuration();
QString dlgTitle = "information消息框";
QString strInfo = QString::fromStdString(s);
QMessageBox::information(this, dlgTitle, strInfo, QMessageBox::Ok, QMessageBox::NoButton);

#ifndef MYTHREAD_H
#define MYTHREAD_H
 
 
#include <QObject>
#include <QThread>
#include <QImage>
 
#include <iostream>
#include <fstream>
extern "C"
{
#include "libavformat/avformat.h"
#include "libavformat/avio.h"
#include "libavcodec/avcodec.h"
#include "libavutil/buffer.h"
#include "libavutil/error.h"
#include "libavutil/mem.h"
#include "libavutil/imgutils.h"
#include <libswscale/swscale.h>
#include <libavutil/imgutils.h>
#include <libavfilter/avfilter.h>
}
 
 
class MyThread : public QThread
{
    Q_OBJECT
public:
    MyThread();
protected:
    void run() override;
signals:
    void minNumToamin(int min);
    void getPicFromFrame(QImage image);
};
 
#endif // MYTHREAD_H

#include <MyThread.h>
#include <QDebug>
 
#define INBUF_SIZE 4096
 
MyThread::MyThread()
{
 
}
 
void MyThread::run()
{
    const char* filename, * outfilename;
    const AVCodec* codec;
    AVCodecParserContext* parser;
    AVCodecContext* c = NULL;
    FILE* f;
    AVFrame* frame;
    AVFrame* pFrameBGR;
    uint8_t inbuf[INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE];
    uint8_t* data;
    size_t   data_size;
    int ret;
    AVPacket* pkt;
    AVFormatContext* inFmtCtx = NULL;
    int video_in_stream_index = -1, audio_in_stream_index = -1;
    AVCodecID src_video_id = AVCodecID::AV_CODEC_ID_NONE, src_audio_id = AVCodecID::AV_CODEC_ID_NONE;
    SwsContext* sws_ctx;
    uint8_t* buffer = nullptr;
 
    //文件路徑
    filename = "C:\\Users\\zyh\\Desktop\\2.mp4";
    outfilename = "";
 
    pkt = av_packet_alloc();
    if (!pkt)
        exit(1);
 
 
    // 打開(kāi)輸入文件
    if ((ret = avformat_open_input(&inFmtCtx, filename, NULL, NULL)) < 0) {
        //LOGD("avformat_open_input() fail");
        //releaseSources();
        return;
    }
    if ((ret = avformat_find_stream_info(inFmtCtx, NULL)) < 0) {
        //LOGD("avformat_find_stream_info fail %d", ret);
        //releaseSources();
        return;
    }
    // 輸出輸入文件信息
    av_dump_format(inFmtCtx, 0, filename, 0);
 
    for (int i = 0; i < inFmtCtx->nb_streams; i++) {
        AVCodecParameters* codecpar = inFmtCtx->streams[i]->codecpar;
        if (codecpar->codec_type == AVMEDIA_TYPE_VIDEO && video_in_stream_index == -1) {
            src_video_id = codecpar->codec_id;
            video_in_stream_index = i;
        }
        if (codecpar->codec_type == AVMEDIA_TYPE_AUDIO && audio_in_stream_index == -1) {
            src_audio_id = codecpar->codec_id;
            audio_in_stream_index = i;
        }
    }
 
 
    /* set end of buffer to 0 (this ensures that no overreading happens for damaged MPEG streams) */
    memset(inbuf + INBUF_SIZE, 0, AV_INPUT_BUFFER_PADDING_SIZE);
 
    /* find the MPEG-1 video decoder */
    codec = avcodec_find_decoder(src_video_id);
    if (!codec) {
        fprintf(stderr, "Codec not found\n");
        exit(1);
    }
 
    parser = av_parser_init(codec->id);
    if (!parser) {
        fprintf(stderr, "parser not found\n");
        exit(1);
    }
 
    c = avcodec_alloc_context3(codec);
    if (!c) {
        fprintf(stderr, "Could not allocate video codec context\n");
        exit(1);
    }
 
    AVCodecParameters* codecpar = inFmtCtx->streams[video_in_stream_index]->codecpar;
    if ((ret = avcodec_parameters_to_context(c, codecpar)) < 0) {
        //LOGD("avcodec_parameters_to_context fail %d", ret);
        //releaseSources();
        return;
    }
 
    /* For some codecs, such as msmpeg4 and mpeg4, width and height
       MUST be initialized there because this information is not
       available in the bitstream. */
    /* open it */
    if (avcodec_open2(c, codec, NULL) < 0) {
        fprintf(stderr, "Could not open codec\n");
        exit(1);
    }
 
    f = fopen(filename, "rb");
    if (!f) {
        fprintf(stderr, "Could not open %s\n", filename);
        exit(1);
    }
 
    frame = av_frame_alloc();
    pFrameBGR = av_frame_alloc();
 
    if (!frame) {
        fprintf(stderr, "Could not allocate video frame\n");
        exit(1);
    }
 
    int index = 0;
    while (av_read_frame(inFmtCtx, pkt) >= 0) {
 
        // 迭代結(jié)束后釋放 av_read_frame 分配的 packet 內(nèi)存
        //std::shared_ptr<AVPacket> packetDeleter(&pkt, av_packet_unref);
 
        if(index >0) break;
        // 說(shuō)明讀取的視頻數(shù)據(jù)
        if (pkt->stream_index == video_in_stream_index) {
            if ((ret = avcodec_send_packet(c, pkt)) < 0) {
                //LOGD("video avcodec_send_packet fail %s", av_err2str(ret));
                //releaseSources();
                return;
            }
            while (true) {
                // 從解碼緩沖區(qū)接收解碼后的數(shù)據(jù)
                if ((ret = avcodec_receive_frame(c, frame)) < 0) {
                    if (ret == AVERROR_EOF) {
                        exit(1);
                        // 解碼緩沖區(qū)結(jié)束了，那么也要flush編碼緩沖區(qū)
                        //doEncodeVideo(NULL);
                    }
                    break;
                }
 
                int numBytes = av_image_get_buffer_size(AV_PIX_FMT_RGB24, c->width, c->height, 1);
                if(buffer == nullptr) buffer = (uint8_t*)av_malloc(numBytes * sizeof(uint8_t));
                av_image_fill_arrays(pFrameBGR->data, pFrameBGR->linesize, buffer, AV_PIX_FMT_RGB24,  c->width, c->height, 1);
 
 
                sws_ctx = sws_getContext(codecpar->width, codecpar->height, (enum AVPixelFormat)codecpar->format,
                    frame->width, frame->height, AV_PIX_FMT_RGB24, SWS_BICUBIC, NULL, NULL, NULL);
 
                sws_scale(sws_ctx, frame->data, frame->linesize, 0, c->height, pFrameBGR->data, pFrameBGR->linesize);
 
                // 圖像轉(zhuǎn)換
                sws_scale(sws_ctx, frame->data, frame->linesize, 0, c->height, pFrameBGR->data, pFrameBGR->linesize);
                
                // 得到QImage
                QImage tempImage((uchar*)pFrameBGR->data[0], c->width, c->height, QImage::Format_RGB888);
                // 對(duì)于qt還是不是很熟悉，理解是傳遞給主線程
                getPicFromFrame(tempImage);
            }
        }
 
        // 因?yàn)槊恳淮巫x取的AVpacket的數(shù)據(jù)大小不一樣，所以用完之后要釋放
        av_packet_unref(pkt);
    }
 
    fclose(f);
 
    av_parser_close(parser);
    avcodec_free_context(&c);
    av_frame_free(&frame);
    av_packet_free(&pkt);
}

#ifndef PLAYIMAGE_H
#define PLAYIMAGE_H
 
#include <QWidget>
 
class PlayImage : public QWidget
{
    Q_OBJECT
public:
    explicit PlayImage(QWidget *parent = nullptr);
 
    void updateImage(const QImage& image);
    void updatePixmap(const QPixmap& pixmap);
 
signals:
 
protected:
    void paintEvent(QPaintEvent *event) override;
 
private:
    QPixmap m_pixmap;
};
 
#endif // PLAYIMAGE_H

#include "playimage.h"
 
#include <QPainter>
 
PlayImage::PlayImage(QWidget *parent) : QWidget(parent)
{
 
}
 
/**
 * @brief        傳入Qimage圖片顯示
 * @param image
 */
void PlayImage::updateImage(const QImage& image)
{
    updatePixmap(QPixmap::fromImage(image));
}
 
/**
 * @brief        傳入QPixmap圖片
 * @param pixmap
 */
void PlayImage::updatePixmap(const QPixmap &pixmap)
{
    m_pixmap = pixmap;
    update();
}
 
/**
 * @brief        使用Qpainter顯示圖片
 * @param event
 */
void PlayImage::paintEvent(QPaintEvent *event)
{
    if(!m_pixmap.isNull())
    {
        QPainter painter(this);
#if 0
        // 經(jīng)過(guò)粗略測(cè)試，QImage先縮放后轉(zhuǎn)為QPixmap的方式在圖像比較小時(shí)耗時(shí)少，圖片越大耗時(shí)遠(yuǎn)大
        QPixmap pixmap = QPixmap::fromImage(m_image.scaled(this->size(), Qt::KeepAspectRatio));
        // 先將QImage轉(zhuǎn)換為QPixmap再進(jìn)行縮放則耗時(shí)比較少，并且穩(wěn)定，不會(huì)因?yàn)榭s放圖片大小而產(chǎn)生太大影響
        QPixmap pixmap1 = QPixmap::fromImage(m_image).scaled(this->size(), Qt::KeepAspectRatio);
#endif
        QPixmap pixmap = m_pixmap.scaled(this->size(), Qt::KeepAspectRatio);
        int x = (this->width() - pixmap.width()) / 2;
        int y = (this->height() - pixmap.height()) / 2;
        painter.drawPixmap(x, y, pixmap);
    }
    QWidget::paintEvent(event);
}

m_thread  =  new MyThread;
connect(m_thread,&MyThread::getPicFromFrame,this,&MainWindow::getPicfromThread);
m_thread->start();

void MainWindow::getPicfromThread(QImage image)
{
    ui->widget->updateImage(image);
}