// tutorial02.c

// A pedagogical video player that will stream through every video frame as fast as it can.

//

// This tutorial was written by Stephen Dranger (dranger@gmail.com).

//

// 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 the Makefile to build all examples.

//

// Run using

// tutorial02 myvideofile.mpg

//

// to play the video stream on your screen.

#include <libavcodec/avcodec.h>

#include <libavformat/avformat.h>

#include <libswscale/swscale.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 = NULL;

int i, videoStream;

AVCodecContext *pCodecCtx = NULL;

AVCodec *pCodec = NULL;

AVFrame *pFrame = NULL;

AVPacket packet;

int frameFinished;

//float aspect_ratio;

AVDictionary *optionsDict = NULL;

struct SwsContext *sws_ctx = NULL;

SDL_Overlay *bmp = NULL;

SDL_Surface *screen = NULL;

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(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

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_open2(pCodecCtx, pCodec, &optionsDict)<0)

return -1; // Could not open codec

// Allocate video frame

pFrame=av_frame_alloc();

// 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);

sws_ctx =

sws_getContext

(

pCodecCtx->width,

pCodecCtx->height,

pCodecCtx->pix_fmt,

pCodecCtx->width,

pCodecCtx->height,

PIX_FMT_YUV420P,

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) {

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

sws_scale

(

sws_ctx,

(uint8_t const * const *)pFrame->data,

pFrame->linesize,

0,

pCodecCtx->height,

pict.data,

pict.linesize

);

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

avformat_close_input(&pFormatCtx);

return 0;

}