FFMEPG -- A ffmpeg and SDL Tutorial : tutorial01.c

參考 http://dranger.com/ffmpeg/tutorial01.html 進行實作練習，發現此篇文章附屬範例已無法在新版本的ffmpeg下正確編譯。以下附上一個可以在 ffmpeg 1.1.1 (build Jan 27 2013) 正確編譯的例子。

// tutorial01.c // Code based on a tutorial by Martin Bohme (boehme@inb.uni-luebeckREMOVETHIS.de) // 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. // 201302023 albert.liao modified start //#include //#include #include #include #include // 201302023 albert.liao modified end #include 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; ydata[0]+y*pFrame->linesize[0], 1, width*3, pFile); // Close file fclose(pFile); } int main(int argc, char *argv[]) { AVFormatContext *pFormatCtx; int i, videoStream; AVCodecContext *pCodecCtx; AVCodec *pCodec; AVFrame *pFrame; AVFrame *pFrameRGB; AVPacket packet; int frameFinished; int numBytes; uint8_t *buffer; static struct SwsContext *img_convert_ctx; if(argc < 2) { printf("Please provide a movie file\n"); return -1; } // Register all formats and codecs av_register_all(); // 201302023 albert.liao modified start // Open video file //if(av_open_input_file(&pFormatCtx, argv[1], NULL, 0, NULL)!=0) if(avformat_open_input(&pFormatCtx, argv[1], NULL, NULL)!=0) return -1; // Couldn't open file // 201302023 albert.liao modified end // Retrieve stream information // 201302023 albert.liao modified start //if(av_find_stream_info(pFormatCtx)<0 data-blogger-escaped--1="" data-blogger-escaped-0="" data-blogger-escaped-201302023="" data-blogger-escaped-about="" data-blogger-escaped-albert.liao="" data-blogger-escaped-argv="" data-blogger-escaped-av_dump_format="" data-blogger-escaped-avformat_find_stream_info="" data-blogger-escaped-couldn="" data-blogger-escaped-dump="" data-blogger-escaped-dump_format="" data-blogger-escaped-end="" data-blogger-escaped-error="" data-blogger-escaped-file="" data-blogger-escaped-find="" data-blogger-escaped-first="" data-blogger-escaped-for="" data-blogger-escaped-i="" data-blogger-escaped-if="" data-blogger-escaped-information="" data-blogger-escaped-modified="" data-blogger-escaped-onto="" data-blogger-escaped-pformatctx-="" data-blogger-escaped-pformatctx="" data-blogger-escaped-return="" data-blogger-escaped-standard="" data-blogger-escaped-stream="" data-blogger-escaped-t="" data-blogger-escaped-the="" data-blogger-escaped-video="" data-blogger-escaped-videostream="-1;">nb_streams; i++) // 201302023 albert.liao modified start //if(pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_VIDEO) { if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO) { // 201302023 albert.liao modified end 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 pCodecCtx=pFormatCtx->streams[videoStream]->codec; // Find the decoder for the video stream pCodec=avcodec_find_decoder(pCodecCtx->codec_id); if(pCodec==NULL) { fprintf(stderr, "Unsupported codec!\n"); return -1; // Codec not found } // 201302023 albert.liao modified start // Open codec //if(avcodec_open(pCodecCtx, pCodec)<0 data-blogger-escaped--1="" data-blogger-escaped-201302023="" data-blogger-escaped-albert.liao="" data-blogger-escaped-allocate="" data-blogger-escaped-an="" data-blogger-escaped-and="" data-blogger-escaped-avcodec_open2="" data-blogger-escaped-avframe="" data-blogger-escaped-buffer="" data-blogger-escaped-codec="" data-blogger-escaped-could="" data-blogger-escaped-determine="" data-blogger-escaped-end="" data-blogger-escaped-frame="" data-blogger-escaped-if="" data-blogger-escaped-modified="" data-blogger-escaped-not="" data-blogger-escaped-null="" data-blogger-escaped-numbytes="avpicture_get_size(PIX_FMT_RGB24," data-blogger-escaped-open="" data-blogger-escaped-pcodec="" data-blogger-escaped-pcodecctx-="" data-blogger-escaped-pcodecctx="" data-blogger-escaped-pframe="avcodec_alloc_frame();" data-blogger-escaped-pframergb="=NULL)" data-blogger-escaped-required="" data-blogger-escaped-return="" data-blogger-escaped-size="" data-blogger-escaped-structure="" data-blogger-escaped-video="">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, PIX_FMT_RGB24, pCodecCtx->width, pCodecCtx->height); // 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_video(pCodecCtx, pFrame, &frameFinished, packet.data, packet.size); avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet); // Did we get a video frame? if(frameFinished) { // 201302023 albert.liao modified start // Convert the image from its native format to RGB //img_convert((AVPicture *)pFrameRGB, PIX_FMT_RGB24, // (AVPicture*)pFrame, pCodecCtx->pix_fmt, pCodecCtx->width, // pCodecCtx->height); img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height,\ pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height,\ PIX_FMT_RGB24, SWS_FAST_BILINEAR, NULL, NULL, NULL); // other codes // Convert the image from its native format to RGB sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize,\ 0, pCodecCtx->height, pFrameRGB->data, pFrameRGB->linesize); // 201302023 albert.liao modified start // 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_free(pFrameRGB); // Free the YUV frame av_free(pFrame); // Close the codec avcodec_close(pCodecCtx); // 201302023 albert.liao modified start // Close the video file // av_close_input_file(pFormatCtx); avformat_close_input(&pFormatCtx); // 201302023 albert.liao modified end return 0; }