ffmpeg视频生成jpg图片截图(一)
实现目标：输入本地文件，实现截图生成jpeg图片到本地，功能点请看注释，注意：注释很重要。
< code_snippet_id="1603323" snippet_file_name="blog_20160309_1_1472172" name="code" class="cpp">//ffmpeg.h#ifndef __FFMPEG_H__#define __FFMPEG_H__#include "info.h"extern "C"{#include <libavutil/imgutils.h>#include <libavformat/avformat.h>#include "libavformat/avio.h"#include "libavcodec/avcodec.h"#include "libswscale/swscale.h"#include "libavutil/avutil.h"#include "libavutil/mathematics.h"#include "libswresample/swresample.h"#include "libavutil/opt.h"#include "libavutil/channel_layout.h"#include "libavutil/samplefmt.h"#include "libavdevice/avdevice.h"#include "libavfilter/avfilter.h"#include "libavutil/error.h"#include "libavutil/mathematics.h" #include "libavutil/time.h" #include "inttypes.h"#include "stdint.h"};#pragma comment(lib,"avformat.lib")#pragma comment(lib,"avcodec.lib")#pragma comment(lib,"avdevice.lib")#pragma comment(lib,"avfilter.lib")#pragma comment(lib,"avutil.lib")#pragma comment(lib,"postproc.lib")#pragma comment(lib,"swresample.lib")#pragma comment(lib,"swscale.lib")#define INPUTURL "../flv/test.flv" #define OUTFILEPATH "../jpg/" extern AVFormatContext * m_in_format_ctx;extern int video_stream_idx;void initialize_all();int init_input(char * filename,AVFormatContext ** in_format);int open_codec_context(int *stream_idx, AVFormatContext ** in_format_ctx, enum AVMediaType type);void uinit_input(AVFormatContext * in_format_ctx);int read_frame(AVFormatContext * in_format,char * filepath);int save_picture_init(AVFormatContext** out_format_ctx,AVStream * video_st,AVCodecContext* pCodecCtx,char * filename);int save_picture_init_2(FILE ** pFile,char * filename);void save_picture_uinit(FILE * pFile,AVPacket pkt);void save_picture_uinit_2(AVFormatContext* out_format_ct,AVPacket pkt);void generate_file_name(char * file_name,char * file_path,long long pts);#endif
< code_snippet_id="1603323" snippet_file_name="blog_20160309_2_2824184" name="code" class="cpp">//ffmpeg.cpp#include "ffmpeg.h"AVFormatContext * m_in_format_ctx = NULL;int video_stream_idx = -1; void initialize_all(){ av_register_all(); avformat_network_init();}int init_input(char * filename,AVFormatContext ** in_format_ctx){ int ret = 0; ret = avformat_open_input(in_format_ctx, filename,NULL, NULL); if (ret != 0) { printf("Call avformat_open_input function failed!\n"); return 0; } if (av_find_stream_info(*in_format_ctx) < 0) { printf("Call av_find_stream_info function failed!\n"); return 0; } ret = open_codec_context(&video_stream_idx, in_format_ctx, AVMEDIA_TYPE_VIDEO); if (ret != 1) { printf("Call open_codec_context function failed!\n"); return 0; } //The output of input information av_dump_format(*in_format_ctx, -1, filename, 0); return 1;}int open_codec_context(int *stream_idx, AVFormatContext ** in_format_ctx, enum AVMediaType type){ int ret = 0; AVStream * st = NULL; AVCodecContext * dec_ctx = NULL; AVCodec * dec = NULL; ret = av_find_best_stream((*in_format_ctx), type, -1, -1, NULL, 0); if (ret < 0) { printf("Call av_find_best_stream function failed!\n"); return 0; } else { *stream_idx = ret; st = (*in_format_ctx)->streams[*stream_idx]; /* find decoder for the stream */ dec_ctx = st->codec; dec = avcodec_find_decoder(dec_ctx->codec_id); if (!dec) { return AVERROR(EINVAL); } if ((ret = avcodec_open2(dec_ctx, dec, NULL)) < 0) { printf("Call avcodec_open2 function failed!\n"); return 0; } } return 1;}void uinit_input(AVFormatContext * in_format_ctx){ avcodec_close(in_format_ctx->streams[video_stream_idx]->codec); avformat_close_input(&in_format_ctx); av_free(in_format_ctx);}int read_frame(AVFormatContext * in_format,char * filepath){ int ret = 0; AVPacket pkt_in; AVPacket pkt_out; AVFrame * picture = av_frame_alloc(); int got_picture_ptr = 0; AVFormatContext* pFormatCtx = NULL; AVStream* video_st = NULL; AVCodecContext* pCodecCtx = NULL; AVCodec* pCodec = NULL; FILE * video_dst_file = NULL; char file_name[50] = {0}; /* find the mpeg1 video encoder */ pCodec = avcodec_find_encoder(AV_CODEC_ID_MJPEG); if (!pCodec) { printf("Call avcodec_find_encoder function failed!\n"); return 0; } pCodecCtx = avcodec_alloc_context3(pCodec); if (!pCodecCtx) { printf("Call avcodec_alloc_context3 function failed!\n"); return 0; } pCodecCtx->codec_type = AVMEDIA_TYPE_VIDEO; pCodecCtx->pix_fmt = AV_PIX_FMT_YUVJ420P; //If you want to change the image size can do the zoom function pCodecCtx->width = in_format->streams[video_stream_idx]->codec->width; pCodecCtx->height = in_format->streams[video_stream_idx]->codec->height; pCodecCtx->time_base.num = 1; pCodecCtx->time_base.den = 15; //Output some information if (avcodec_open2(pCodecCtx, pCodec,NULL) < 0) { printf("Could not open codec.\n"); return 0; } av_init_packet(&pkt_in); av_init_packet(&pkt_out); //return 0 if OK, < 0 on error or end of file while (av_read_frame(in_format, &pkt_in) == 0) { //video && key frame if (pkt_in.stream_index == video_stream_idx && pkt_in.flags == 1) { ret = avcodec_decode_video2(in_format->streams[video_stream_idx]->codec, picture, &got_picture_ptr, &pkt_in); //success decode if(got_picture_ptr) { av_new_packet(&pkt_out,pCodecCtx->width * pCodecCtx->height * 3); //encode ret = avcodec_encode_video2(pCodecCtx, &pkt_out,picture, &got_picture_ptr); if(ret < 0) { printf("Encode Error.\n"); avcodec_close(pCodecCtx); av_free(pCodecCtx); av_free_packet(&pkt_out); return 0; } //success encode if (got_picture_ptr) { generate_file_name(file_name,filepath,pkt_in.pts); //Method 1 //save_picture_init(&pFormatCtx,video_st,pCodecCtx,file_name); //save_picture_uinit_2(pFormatCtx,pkt_out); //Method 2 save_picture_init_2(&video_dst_file,file_name); if(video_dst_file) { save_picture_uinit(video_dst_file,pkt_out); } } } } av_free_packet(&pkt_in); } av_frame_free(&picture); avcodec_close(pCodecCtx); av_free(pCodecCtx); return 1;}int save_picture_init(AVFormatContext** out_format_ctx,AVStream * video_st,AVCodecContext* pCodecCtx,char * filename){ AVOutputFormat* fmt = NULL; avformat_alloc_output_context2(out_format_ctx, NULL, NULL, filename); fmt = (*out_format_ctx)->oformat; video_st = avformat_new_stream((*out_format_ctx), 0); if (video_st == NULL) { return 0; } /*pCodecCtx = video_st->codec; pCodecCtx->codec_id = fmt->video_codec; */ av_dump_format((*out_format_ctx), 0, filename, 1); if (avformat_write_header((*out_format_ctx), NULL)) { printf("Call avformat_write_header function failed.\n"); return 0 ; } return 1;}int save_picture_init_2(FILE ** pFile,char * filename){ *pFile = fopen(filename, "wb"); return 1;}void save_picture_uinit(FILE * pFile,AVPacket pkt){ fwrite(pkt.data, sizeof(uint8_t),pkt.size, pFile); fclose(pFile); av_free_packet(&pkt);}void save_picture_uinit_2(AVFormatContext* out_format_ct,AVPacket pkt){ int ret = 0; //pkt.stream_index = video_st->index; ret = av_interleaved_write_frame(out_format_ct, &pkt); if (ret != 0) { printf("error av_interleaved_write_frame _ video\n"); return ; } //Write Trailer ret = av_write_trailer(out_format_ct); if (ret != 0) { printf("error av_interleaved_write_frame _ video\n"); } av_free(out_format_ct);}void generate_file_name(char * file_name,char * file_path,long long pts){ if (file_path[strlen(file_path) - 1] == '/') { sprintf(file_name,"%s%lld.jpg",file_path,pts); } else { sprintf(file_name,"%s/%lld.jpg",file_path,pts); }}
实现效果：
源码地址：http://download..net/detail/zhuweigangzwg/9456776
交流请加QQ群：62054820
QQ：379969650.
