ffmpeg(1)环境搭建+tutorial01.c

环境搭建

1）将ffmpeg-20121125-git-26c531c-win32-shared\bin加入到环境变量中。

2）将SDL-1.2.15\include，ffmpeg-20121125-git-26c531c-win32-dev\include加入到工程中，如图示：

3）在附加依赖库中添加如下lib文件

SDL.lib
SDLmain.lib
avcodec.lib
avformat.lib
avdevice.lib
avfilter.lib
avutil.lib
swscale.lib
swresample.lib
postproc.lib

4）导入tutorial01.c工程

 

// tutorial01.c// Code based on a tutorial by Martin Bohme ([e-mail])// Tested on Gentoo, CVS version 5/01/07 compiled with GCC 4.1.1// A small sample program that shows how to use libavformat and libavcodec to// read video from a file.//// Use//// gcc -o tutorial01 tutorial01.c -lavformat -lavcodec -lz//// to build (assuming libavformat and libavcodec are correctly installed// your system).//// Run using//// tutorial01 myvideofile.mpg//// to write the first five frames from "myvideofile.mpg" to disk in PPM// format.extern "C"{#include <libavcodec\avcodec.h>#include <libavformat\avformat.h>//******************************************************************************#include <libavutil/avstring.h>#include <libswscale/swscale.h>//*********************************************************************************}#include <stdio.h>#include <math.h>#include <iostream>using namespace std ;void SaveFrame(AVFrame *pFrame, int width, int height, int iFrame) {FILE *pFile;char szFilename[32];int  y;  // Open filesprintf(szFilename, "frame%d.ppm", iFrame);pFile=fopen(szFilename, "wb");if(pFile==NULL)return;// Write headerfprintf(pFile, "P6\n%d %d\n255\n", width, height);// Write pixel datafor(y=0; y<height; y++)fwrite(pFrame->data[0]+y*pFrame->linesize[0], 1, width*3, pFile);// Close filefclose(pFile);}int main(int argc, char *argv[]) {AVFormatContext *pFormatCtx = avformat_alloc_context();//！！！这一句没有加后面部分时会有错误，会在执行avformat_open_input函数报错int             i, videoStream;AVCodecContext  *pCodecCtx;AVCodec         *pCodec;AVFrame         *pFrame; AVFrame         *pFrameRGB;AVPacket        packet;int             frameFinished;int             numBytes;uint8_t         *buffer;    struct SwsContext *img_convert_ctx;const char * filename="c:\\1.mp4";// Register all formats and codecsav_register_all(); // Open video fileif(avformat_open_input(&pFormatCtx, filename, NULL, NULL)!=0)return -1; // Couldn't open file// Retrieve stream informationif(av_find_stream_info(pFormatCtx)<0)return -1; // Couldn't find stream information// Dump information about file onto standard errorav_dump_format(pFormatCtx, 0, filename, 0);// Find the first video streamvideoStream=-1;for(i=0; i<pFormatCtx->nb_streams; i++)if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO) {videoStream=i;break;}if(videoStream==-1)return -1; // Didn't find a video stream// Get a pointer to the codec context for the video streampCodecCtx=pFormatCtx->streams[videoStream]->codec;// Find the decoder for the video streampCodec=avcodec_find_decoder(pCodecCtx->codec_id);if(pCodec==NULL) {fprintf(stderr, "Unsupported codec!\n");return -1; // Codec not found}// Open codecif(avcodec_open(pCodecCtx, pCodec)<0)return -1; // Could not open codec// Allocate video framepFrame=avcodec_alloc_frame();// Allocate an AVFrame structurepFrameRGB=avcodec_alloc_frame();if(pFrameRGB==NULL)return -1;// Determine required buffer size and allocate buffernumBytes=avpicture_get_size(PIX_FMT_RGB24, pCodecCtx->width,pCodecCtx->height);buffer=(uint8_t *)av_malloc(numBytes*sizeof(uint8_t));// Assign appropriate parts of buffer to image planes in pFrameRGB// Note that pFrameRGB is an AVFrame, but AVFrame is a superset// of AVPictureavpicture_fill((AVPicture *)pFrameRGB, buffer, PIX_FMT_RGB24,pCodecCtx->width, pCodecCtx->height);// Read frames and save first five frames to diski=0;while(av_read_frame(pFormatCtx, &packet)>=0) {  // Is this a packet from the video stream?if(packet.stream_index==videoStream){// Decode video frameavcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);// Did we get a video frame?if(frameFinished){img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, PIX_FMT_RGB565,SWS_BILINEAR, NULL, NULL, NULL); if (img_convert_ctx == NULL)  {  fprintf(stderr, "Cannot initialize the conversion context/n");  exit(1);  }  sws_scale(img_convert_ctx,(const uint8_t* const*)pFrame->data,pFrame->linesize,0,pCodecCtx->height,pFrameRGB->data,pFrameRGB->linesize);if(++i<=5)SaveFrame(pFrameRGB, pCodecCtx->width, pCodecCtx->height, i);}}}// Free the packet that was allocated by av_read_frameav_free_packet(&packet);// Free the RGB imageav_free(buffer);av_free(pFrameRGB);// Free the YUV frameav_free(pFrame);// Free the SwsContextsws_freeContext(img_convert_ctx);// Close the codecavcodec_close(pCodecCtx);return 0;}

总结：

1）调试时，朋友给的代码，很多错误，所以还是从官网自己下载比较好，另外，这个是最新版本的，ffmpeg修改了很多接口

2）tutorial01提供了很好的操作视频的基本方法，只要你处理视频，就必须使用这些方法。

下面对tutorial2进行调试，当然这些基本的只是练手和熟悉ffmpeg，最终还是为了自己的编解码和小型播放器