INCLUDEPATH +="E:\\Lib\\ffmpeg\\include"LIBS += -LE:\Lib\ffmpeg\lib -lavutil -lavformat -lavcodec -lavdevice -lavfilter -lpostproc -lswresample -lswscale

#include <QTime>
extern "C"{
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libavutil/imgutils.h>
}
void Delay(int msec)
{QTime dieTime = QTime::currentTime().addMSecs(msec);while( QTime::currentTime() < dieTime )QCoreApplication::processEvents(QEventLoop::AllEvents, 100);
}void MainWindow::on_btnPlay_clicked()
{AVFormatContext    *pFormatCtx;int                i, videoindex;AVCodecContext    *pCodecCtx;AVCodec            *pCodec;AVFrame    *pFrame, *pFrameRGB;unsigned char *out_buffer;AVPacket *packet;int ret, got_picture;struct SwsContext *img_convert_ctx;char filepath[] = "E:\\media\\1.avi";//初始化编解码库
    av_register_all();//创建AVFormatContext对象，与码流相关的结构。pFormatCtx = avformat_alloc_context();//初始化pFormatCtx结构if (avformat_open_input(&pFormatCtx, filepath, NULL, NULL) != 0){printf("Couldn't open input stream.\n");return ;}//获取音视频流数据信息if (avformat_find_stream_info(pFormatCtx, NULL) < 0){printf("Couldn't find stream information.\n");return ;}videoindex = -1;//nb_streams视音频流的个数，这里当查找到视频流时就中断了。for (i = 0; i < pFormatCtx->nb_streams; i++)if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO){videoindex = i;break;}if (videoindex == -1){printf("Didn't find a video stream.\n");return ;}//获取视频流编码结构pCodecCtx = pFormatCtx->streams[videoindex]->codec;//查找解码器pCodec = avcodec_find_decoder(pCodecCtx->codec_id);if (pCodec == NULL){printf("Codec not found.\n");return ;}//用于初始化pCodecCtx结构if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0){printf("Could not open codec.\n");return ;}//创建帧结构，此函数仅分配基本结构空间，图像数据空间需通过av_malloc分配pFrame = av_frame_alloc();pFrameRGB = av_frame_alloc();//创建动态内存,创建存储图像数据的空间//av_image_get_buffer_size获取一帧图像需要的大小out_buffer = (unsigned char *)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_RGB32, pCodecCtx->width, pCodecCtx->height, 1));av_image_fill_arrays(pFrameRGB->data, pFrameRGB->linesize, out_buffer,AV_PIX_FMT_RGB32, pCodecCtx->width, pCodecCtx->height, 1);packet = (AVPacket *)av_malloc(sizeof(AVPacket));//Output Info-----------------------------printf("--------------- File Information ----------------\n");//此函数打印输入或输出的详细信息av_dump_format(pFormatCtx, 0, filepath, 0);printf("-------------------------------------------------\n");//初始化img_convert_ctx结构img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_RGB32, SWS_BICUBIC, NULL, NULL, NULL);//av_read_frame读取一帧未解码的数据while (av_read_frame(pFormatCtx, packet) >= 0){//如果是视频数据if (packet->stream_index == videoindex){//解码一帧视频数据ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);if (ret < 0){printf("Decode Error.\n");return ;}if (got_picture){sws_scale(img_convert_ctx, (const unsigned char* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height,pFrameRGB->data, pFrameRGB->linesize);QImage img((uchar*)pFrameRGB->data[0],pCodecCtx->width,pCodecCtx->height,QImage::Format_RGB32);ui->label->setPixmap(QPixmap::fromImage(img));Delay(40);}}av_free_packet(packet);}sws_freeContext(img_convert_ctx);av_frame_free(&pFrameRGB);av_frame_free(&pFrame);avcodec_close(pCodecCtx);avformat_close_input(&pFormatCtx);
}