最近在学习FFMPEG,看了很多的例子都是在Windows下的,这里提供一个linux下的一个简单程序,由雷神的工程修改而来。
#include <stdio.h> #define __STDC_CONSTANT_MACROS #include "avformat.h" #include "avcodec.h" #include "swscale.h" int main(int argc, char* argv[]) { AVFormatContext *pFormatCtx; int i, videoindex; AVCodecContext *pCodecCtx; AVCodec *pCodec; AVFrame *pFrame,*pFrameYUV; uint8_t *out_buffer; AVPacket *packet; int y_size; int ret, got_picture; struct SwsContext *img_convert_ctx; //输入文件路径 char filepath[]="../testfile/school.flv"; int frame_cnt; av_register_all(); /* 注册复用器 编码器 */ avformat_network_init(); /* 打开网络流 */ pFormatCtx = avformat_alloc_context(); /* 分配内存 */ if(avformat_open_input(&pFormatCtx,filepath,NULL,NULL)!=0){ printf("Couldn't open input stream.\n"); return -1; } if(avformat_find_stream_info(pFormatCtx,NULL)<0){ /* 读取一部分视音频数据并且获得一些相关的信息 */ printf("Couldn't find stream information.\n"); return -1; } videoindex=-1; 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 -1; } pCodecCtx=pFormatCtx->streams[videoindex]->codec; pCodec=avcodec_find_decoder(pCodecCtx->codec_id); /* 查找FFmpeg的解码器 */ if(pCodec==NULL){ printf("Codec not found.\n"); return -1; } if(avcodec_open2(pCodecCtx, pCodec,NULL)<0){ /* 初始化一个视音频编解码器的AVCodecContext */ printf("Could not open codec.\n"); return -1; } /* printf information of the input video */ printf("AVFormatContext AVInputFormat name = %s \n",pFormatCtx->iformat->name); printf("Number of elements in AVFormatContext.streams = %d \n",pFormatCtx->nb_streams); printf("Duration of the stream, in AV_TIME_BASE fractional = %d \n",pFormatCtx->duration); printf("Total stream bitrate in %d bit/s \n",pFormatCtx->bit_rate); printf("picture width = %d \n",pCodecCtx->width); printf("picture height = %d \n",pCodecCtx->height); pFrame=av_frame_alloc(); /* 分配一个 AVFrame 的内存*/ pFrameYUV=av_frame_alloc(); out_buffer=(uint8_t *)av_malloc(avpicture_get_size(AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height)); /*内存分配函数 */ avpicture_fill((AVPicture *)pFrameYUV, out_buffer, AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height); /* 为已经分配的空间的结构体AVPicture挂上一段用于保存数据的空间 */ packet=(AVPacket *)av_malloc(sizeof(AVPacket)); printf("--------------- File Information ----------------\n"); av_dump_format(pFormatCtx,0,filepath,0); printf("-------------------------------------------------\n"); img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL); /* 初始化SwsContext的函数 */ frame_cnt=0; //FILE* h264_fd = fopen("test.h264", wb+); while(av_read_frame(pFormatCtx, packet)>=0){ if(packet->stream_index==videoindex){ // fwrite(packet->data,packet->size, 1 h264_fd); ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet); /* 解码一帧视频数据 */ if(ret < 0){ printf("Decode Error.\n"); return -1; } if(got_picture){ sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameYUV->data, pFrameYUV->linesize); /* 转换像素的函数 */ //printf("Decoded frame index: %d\n",frame_cnt); frame_cnt++; } } av_free_packet(packet); } //fclose(h264_fd); sws_freeContext(img_convert_ctx); av_frame_free(&pFrameYUV); av_frame_free(&pFrame); avcodec_close(pCodecCtx); avformat_close_input(&pFormatCtx); return 0; }
Makefile 文件如下,头文件和库文件的目录会因为安装目录的不同而不同。
OUT_APP = test INCLUDE_PATH = /usr/local/include/ INCLUDE = -I$(INCLUDE_PATH)libavutil/ -I$(INCLUDE_PATH)libavdevice/ \ -I$(INCLUDE_PATH)libavcodec/ -I$(INCLUDE_PATH)libswresample \ -I$(INCLUDE_PATH)libavfilter/ -I$(INCLUDE_PATH)libavformat \ -I$(INCLUDE_PATH)libswscale/ FFMPEG_LIBS = -lavformat -lavutil -lavdevice -lavcodec -lswresample -lavfilter -lswscale SDL_LIBS = LIBS = $(FFMPEG_LIBS)$(SDL_LIBS) COMPILE_OPTS = $(INCLUDE) C = c OBJ = o C_COMPILER = cc C_FLAGS = $(COMPILE_OPTS) $(CPPFLAGS) $(CFLAGS) LINK = cc -o LINK_OPTS = -lz -lm -lpthread LINK_OBJ = echo_information.o .$(C).$(OBJ): $(C_COMPILER) -c $(C_FLAGS) $< $(OUT_APP): $(LINK_OBJ) $(LINK)$@ $(LINK_OBJ) $(LIBS) $(LINK_OPTS) clean: -rm -rf *.$(OBJ) $(OUT_APP) core *.core *~ include/*~