// tutorial02.c// A pedagogical video player that will stream through every video frame as fast as it can.//// Code based on FFplay, Copyright (c) 2003 Fabrice Bellard, // and a tutorial by Martin Bohme (boehme@inb.uni-luebeckREMOVETHIS.de)// Tested on Gentoo, CVS version 5/01/07 compiled with GCC 4.1.1// Use//// gcc -o tutorial02 tutorial02.c -lavutil -lavformat -lavcodec -lz -lm `sdl-config --cflags --libs`// to build (assuming libavformat and libavcodec are correctly installed, // and assuming you have sdl-config. Please refer to SDL docs for your installation.)//// Run using// tutorial02 myvideofile.mpg//// to play the video stream on your screen.#include <avcodec.h>#include <avformat.h>#include <SDL.h>#include <SDL_thread.h>#ifdef __MINGW32__#undef main /* Prevents SDL from overriding main() */#endif#include <stdio.h>int main(int argc, char *argv[]) {  AVFormatContext *pFormatCtx;  int             i, videoStream;  AVCodecContext  *pCodecCtx;  AVCodec         *pCodec;  AVFrame         *pFrame;   AVPacket        packet;  int             frameFinished;  float           aspect_ratio;  SDL_Overlay     *bmp;  SDL_Surface     *screen;  SDL_Rect        rect;  SDL_Event       event;  if(argc < 2) {    fprintf(stderr, "Usage: test <file>\n");    exit(1);  }  // Register all formats and codecs  av_register_all();    if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {    fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError());    exit(1);  }  // Open video file  if(av_open_input_file(&pFormatCtx, argv[1], NULL, 0, NULL)!=0)    return -1; // Couldn't open file    // Retrieve stream information  if(av_find_stream_info(pFormatCtx)<0)    return -1; // Couldn't find stream information    // Dump information about file onto standard error  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==CODEC_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  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  }    // Open codec  if(avcodec_open(pCodecCtx, pCodec)<0)    return -1; // Could not open codec    // Allocate video frame  pFrame=avcodec_alloc_frame();  // Make a screen to put our video#ifndef __DARWIN__        screen = SDL_SetVideoMode(pCodecCtx->width, pCodecCtx->height, 0, 0);#else        screen = SDL_SetVideoMode(pCodecCtx->width, pCodecCtx->height, 24, 0);#endif  if(!screen) {    fprintf(stderr, "SDL: could not set video mode - exiting\n");    exit(1);  }    // Allocate a place to put our YUV image on that screen  bmp = SDL_CreateYUVOverlay(pCodecCtx->width,				 pCodecCtx->height,				 SDL_YV12_OVERLAY,				 screen);  // 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);            // Did we get a video frame?      if(frameFinished) {	SDL_LockYUVOverlay(bmp);	AVPicture pict;	pict.data[0] = bmp->pixels[0];	pict.data[1] = bmp->pixels[2];	pict.data[2] = bmp->pixels[1];	pict.linesize[0] = bmp->pitches[0];	pict.linesize[1] = bmp->pitches[2];	pict.linesize[2] = bmp->pitches[1];	// Convert the image into YUV format that SDL uses	img_convert(&pict, PIX_FMT_YUV420P,                    (AVPicture *)pFrame, pCodecCtx->pix_fmt, 		    pCodecCtx->width, pCodecCtx->height);		SDL_UnlockYUVOverlay(bmp);		rect.x = 0;	rect.y = 0;	rect.w = pCodecCtx->width;	rect.h = pCodecCtx->height;	SDL_DisplayYUVOverlay(bmp, &rect);            }    }        // Free the packet that was allocated by av_read_frame    av_free_packet(&packet);    SDL_PollEvent(&event);    switch(event.type) {    case SDL_QUIT:      SDL_Quit();      exit(0);      break;    default:      break;    }  }    // Free the YUV frame  av_free(pFrame);    // Close the codec  avcodec_close(pCodecCtx);    // Close the video file  av_close_input_file(pFormatCtx);    return 0;}