FFmpeg 学习之 解码并 MFC+OpenCV 显示

众所周知，Opencv 在图像处理方面具有无与伦比的优势，但其在视频解码这块实在不敢恭维，智能识别 AVI 封装和少数几种 编码格式。

其实 OpenCV 解码也是引用的 FFmpeg，不过编译时估计做了限制。

下面的代码实现的功能是，，FFmpeg 解码视频，然后将每一帧转换为 OpenCV 可以识别的图像格式，在 MFC 图片空间中显示。

配置：VS2008，OpenCV2.4.4，FFmpeg 为11月末的最新版本。

至于工程配置，自己根据实际情况斟酌。

主线程解码存在锁死情况，所以采用了定时器。便于后期的图像处理。

//Dlg.h#pragma once#ifndef INT64_C#define INT64_C(c) (c##LL)#define UINT64_C(c) (c##LL)#endif#ifdef __cplusplusextern "C"{#endif#include "libavformat/avformat.h"#include "libavcodec/avcodec.h"#include "libswscale/swscale.h"#ifdef __cplusplus}#endif#include "cv.h"#include "highgui.h"#include "CvvImage.h"#pragma comment(lib, "swscale.lib")#pragma comment(lib, "avcodec.lib")#pragma comment(lib, "avutil.lib")#pragma comment(lib, "avformat.lib")// CMFC_FFmpegDlg 对话框class CMFC_FFmpegDlg : public CDialog{// 构造public:CMFC_FFmpegDlg(CWnd* pParent = NULL);// 标准构造函数// 对话框数据enum { IDD = IDD_MFC_FFMPEG_DIALOG };protected:virtual void DoDataExchange(CDataExchange* pDX);// DDX/DDV 支持// 实现protected:HICON m_hIcon;// 生成的消息映射函数virtual BOOL OnInitDialog();afx_msg void OnSysCommand(UINT nID, LPARAM lParam);afx_msg void OnPaint();afx_msg HCURSOR OnQueryDragIcon();DECLARE_MESSAGE_MAP()public:afx_msg void OnBnClickedBload();afx_msg void OnTimer(UINT nIDEvent);public:void DrawPicToHDC(IplImage *img, UINT ID);char * filename;int videoStream;int frameFinished;int numBytes;uint8_t * buffer;AVPacket * packet;AVFrame * pFrameRGB;AVFrame * pFrame;AVCodec * pCodec;AVCodecContext * pCodecCtx;AVFormatContext * pFormatCtx;};

//Dlg.cppvoid CMFC_FFmpegDlg::OnBnClickedBload(){// TODO: 在此添加控件通知处理程序代码CFileDialog  dlgFile( TRUE, NULL, NULL,  OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT | OFN_NOCHANGEDIR,   "视频文件格式AVI file format (*.*)|*.*|", NULL);CString filein;    if(dlgFile.DoModal() != IDOK)    {filein = "";       return;    }    filein = dlgFile.GetPathName();filename = (LPSTR)(LPCSTR)filein;AfxMessageBox(filename);av_register_all();avformat_network_init();pFormatCtx = avformat_alloc_context();if(avformat_open_input(&pFormatCtx, filename, NULL, NULL)!=0){AfxMessageBox("open  input  file  faile !");return ;}AfxMessageBox("open  input  file !");    for(int i=0; i<pFormatCtx->nb_streams; i++) {        if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO)          {              videoStream = i;              break;          }}if(videoStream == -1){AfxMessageBox("could  not find video stream !");return ;}AfxMessageBox("find video stream !");pCodecCtx=pFormatCtx->streams[videoStream]->codec;pCodec=avcodec_find_decoder(pCodecCtx->codec_id);      if(pCodec==NULL)      {          AfxMessageBox("could not find decoder");          return ;      }AfxMessageBox("find decoder");if(avcodec_open2(pCodecCtx, pCodec,NULL)<0)      {        AfxMessageBox("could not open decoder");          return ;    }AfxMessageBox("open decoder");av_dump_format(pFormatCtx, 0, filename, 0);pFrame=avcodec_alloc_frame();pFrameRGB=avcodec_alloc_frame();packet=(AVPacket *)av_malloc(sizeof(AVPacket));if(pFrameRGB==NULL){AfxMessageBox("open mem faile");return ;}numBytes=avpicture_get_size(PIX_FMT_RGB24, pCodecCtx->width,pCodecCtx->height);buffer=(uint8_t *)av_malloc(numBytes*sizeof(uint8_t));avpicture_fill((AVPicture *)pFrameRGB, buffer, PIX_FMT_RGB24,pCodecCtx->width, pCodecCtx->height);cvNamedWindow("video", 1);SetTimer(1, 10, NULL);}

//Dlg.cppvoid  CMFC_FFmpegDlg::OnTimer(UINT nIDEvent){if(av_read_frame(pFormatCtx, packet)>=0) {if(packet->stream_index==videoStream) {avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished,  packet);if(frameFinished) {struct SwsContext * img_convert_ctx;img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,  pCodecCtx->width, pCodecCtx->height, PIX_FMT_RGB24, SWS_BICUBIC, NULL, NULL, NULL);if(img_convert_ctx == NULL){AfxMessageBox("Cannot initialize the conversion context !");return ;}static uchar *p = NULL; p = pFrame->data[1];pFrame->data[1] = pFrame->data[2];pFrame->data[2] = p;sws_scale(img_convert_ctx,pFrame->data, pFrame->linesize, 0, pCodecCtx->height,pFrameRGB->data, pFrameRGB->linesize);if (img_convert_ctx){sws_freeContext (img_convert_ctx); img_convert_ctx = NULL;}IplImage * Image;CvSize Size = cvSize(pCodecCtx->width, pCodecCtx->height);Image = cvCreateImage(Size, IPL_DEPTH_8U, 3); memcpy(Image->imageData, buffer, pCodecCtx->width*pCodecCtx->height*24/8);Image->widthStep = pCodecCtx->width*3; Image->origin = 0;cvShowImage("video", Image);DrawPicToHDC(Image, IDC_PIC);UpdateData(FALSE);                    cvReleaseImage( &Image);}}}}void CMFC_FFmpegDlg::DrawPicToHDC(IplImage *img, UINT ID){CDC *pDC = GetDlgItem(ID)->GetDC();     HDC hDC= pDC->GetSafeHdc(); CRect rect;    GetDlgItem(ID)->GetClientRect(&rect);     CvvImage cimg;     cimg.CopyOf(img,1);        cimg.DrawToHDC(hDC,&rect);     ReleaseDC(pDC); }