ffmpeg 프레임 추출 예제
2021-01-18
ffmpeg 을 이용한 비디오 파일에서 첫 다섯개의 프레임 이미지 추출 예제..
makefile
all: gcc ./test.c -I/c/Temp/ffmpeg_win65/include -L/c/Temp/ffmpeg_win64/lib -lavformat -lavcodec -lswscale -lavutil -lswresample -lz -lbcrypt -lole32 -lMfplat -ltiff -liconv -llzma -lws2_32 -lSecur32 -lbz2 -lstrmiids
test.c
#include <libavcodec/avcodec.h> #include <libavformat/avformat.h> #include <libswscale/swscale.h> #include <stdio.h> // compatibility with newer API #if LIBAVCODEC_VERSION_INT < AV_VERSION_INT(55,28,1) #define av_frame_alloc avcodec_alloc_frame #define av_frame_free avcodec_free_frame #endif void SaveFrame(AVFrame *pFrame, int width, int height, int iFrame) { FILE *pFile; char szFilename[32]; int y; // Open file sprintf(szFilename, "frame%d.ppm", iFrame); pFile=fopen(szFilename, "wb"); if(pFile==NULL) return; // Write header fprintf(pFile, "P6\n%d %d\n255\n", width, height); // Write pixel data for(y=0; y<height; y++) fwrite(pFrame->data[0]+y*pFrame->linesize[0], 1, width*3, pFile); // Close file fclose(pFile); } int main(int argc, char *argv[]) { // Initalizing these to NULL prevents segfaults! AVFormatContext *pFormatCtx = NULL; int i, videoStream; AVCodecContext *pCodecCtxOrig = NULL; AVCodecContext *pCodecCtx = NULL; AVCodec *pCodec = NULL; AVFrame *pFrame = NULL; AVFrame *pFrameRGB = NULL; AVPacket packet; int frameFinished; int numBytes; uint8_t *buffer = NULL; struct SwsContext *sws_ctx = NULL; if(argc < 2) { printf("Please provide a movie file\n"); return -1; } // Register all formats and codecs av_register_all(); // Open video file if(avformat_open_input(&pFormatCtx, argv[1], NULL, NULL)!=0) return -1; // Couldn't open file // Retrieve stream information if(avformat_find_stream_info(pFormatCtx, NULL)<0) return -1; // Couldn't find stream information // Dump information about file onto standard error av_dump_format(pFormatCtx, 0, argv[1], 0); // Find the first video stream videoStream=-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 stream pCodecCtxOrig=pFormatCtx->streams[videoStream]->codec; // Find the decoder for the video stream pCodec=avcodec_find_decoder(pCodecCtxOrig->codec_id); if(pCodec==NULL) { fprintf(stderr, "Unsupported codec!\n"); return -1; // Codec not found } // Copy context pCodecCtx = avcodec_alloc_context3(pCodec); if(avcodec_copy_context(pCodecCtx, pCodecCtxOrig) != 0) { fprintf(stderr, "Couldn't copy codec context"); return -1; // Error copying codec context } // Open codec if(avcodec_open2(pCodecCtx, pCodec, NULL)<0) return -1; // Could not open codec // Allocate video frame pFrame=av_frame_alloc(); // Allocate an AVFrame structure pFrameRGB=av_frame_alloc(); if(pFrameRGB==NULL) return -1; // Determine required buffer size and allocate buffer numBytes=avpicture_get_size(AV_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 AVPicture avpicture_fill((AVPicture *)pFrameRGB, buffer, AV_PIX_FMT_RGB24, pCodecCtx->width, pCodecCtx->height); // initialize SWS context for software scaling sws_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_RGB24, SWS_BILINEAR, NULL, NULL, NULL ); // Read frames and save first five frames to disk i=0; while(av_read_frame(pFormatCtx, &packet)>=0) { // Is this a packet from the video stream? if(packet.stream_index==videoStream) { // Decode video frame avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet); // Did we get a video frame? if(frameFinished) { //avcodec_align_dimensions2 (pCodecCtx, &pCodecCtx->width, &pCodecCtx->height, pFrameRGB->linesize); // Convert the image from its native format to RGB sws_scale(sws_ctx, (uint8_t const * const *)pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameRGB->data, pFrameRGB->linesize); // Save the frame to disk if(++i<=5) SaveFrame(pFrameRGB, pCodecCtx->width, pCodecCtx->height, i); } } // Free the packet that was allocated by av_read_frame av_free_packet(&packet); } // Free the RGB image av_free(buffer); av_frame_free(&pFrameRGB); // Free the YUV frame av_frame_free(&pFrame); // Close the codecs avcodec_close(pCodecCtx); avcodec_close(pCodecCtxOrig); // Close the video file avformat_close_input(&pFormatCtx); return 0; }
Categorized as: Programming
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