ffmpeg+sdl教程----编写一个简单的播放器2(输出视频到屏幕)

下面完整代码，在vc2005下编译通过。可以看到，程序运行后视频播放出来了，但是由于没有加入播放延迟，视频简直跑疯了，为视频加入延迟将在教程五中实现，目前可以简单地让程序在播放完一帧后，sleep若干秒，改善一下运行状况。

// ffmpegExe.cpp: 主项目文件。#include "stdafx.h"#include "libavformat/avformat.h"#include "libswscale/swscale.h"//#include <windows.h>#include <stdlib.h>#include <stdio.h>#include <string.h>#include <math.h>#include <SDL/SDL.h>#ifdef main#undef main#endif#define SDL_AUDIO_BUFFER_SIZE 1024static int sws_flags = SWS_BICUBIC;int main(int argc, char *argv[]){AVFormatContext *pFormatCtx;int i, videoStream(-1);AVCodecContext *pCodecCtx;AVCodec *pCodec;AVFrame *pFrame;AVPacket packet;int frameFinished;float aspect_ratio;AVCodecContext *aCodecCtx;SDL_Overlay *bmp;SDL_Surface *screen;SDL_Rect rect;SDL_Event event;if(argc < 2){fprintf(stderr, "Usage: test /n");exit(1);}av_register_all();pFormatCtx = av_alloc_format_context(); if (!pFormatCtx) { fprintf(stderr, "Memory error/n"); exit(1); }if(av_open_input_file(&pFormatCtx, argv[1], NULL, 0, NULL)!=0)return -1; // Couldn't open fileif(av_find_stream_info(pFormatCtx)<0)return -1; // Couldn't find stream information// Dump information about file onto standard errordump_format(pFormatCtx, 0, argv[1], 0);// Find the first video streamfor(i=0; i<pFormatCtx->nb_streams; i++){if(pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_VIDEO && videoStream<0){videoStream=i;}}if(videoStream==-1) return -1; // Didn't find a video stream// Get a pointer to the codec context for the video streampCodecCtx=pFormatCtx->streams[videoStream]->codec;pCodec=avcodec_find_decoder(pCodecCtx->codec_id);if(pCodec==NULL){fprintf(stderr, "Unsupported codec!/n");return -1; // Codec not found}// Open codecif(avcodec_open(pCodecCtx, pCodec)<0)return -1; // Could not open codec// Allocate video framepFrame=avcodec_alloc_frame();uint8_t *buffer;int numBytes;// Determine required buffer size and allocate buffernumBytes=avpicture_get_size(PIX_FMT_RGB24, pCodecCtx->width,pCodecCtx->height);buffer=(uint8_t *)av_malloc(numBytes*sizeof(uint8_t));if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)){fprintf(stderr, "Could not initialize SDL - %s/n", SDL_GetError());exit(1);}#ifndef __DARWIN__screen = SDL_SetVideoMode(pCodecCtx->width, pCodecCtx->height, 0, 0);#elsescreen = SDL_SetVideoMode(pCodecCtx->width, pCodecCtx->height, 24, 0);#endifif(!screen){fprintf(stderr, "SDL: could not set video mode - exiting/n");exit(1);}bmp = SDL_CreateYUVOverlay(pCodecCtx->width, pCodecCtx->height,SDL_YV12_OVERLAY, screen);static struct SwsContext *img_convert_ctx;if (img_convert_ctx == NULL){ img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, PIX_FMT_YUV420P, sws_flags, NULL, NULL, NULL); if (img_convert_ctx == NULL){ fprintf(stderr, "Cannot initialize the conversion context/n"); exit(1); } }i=0;while(av_read_frame(pFormatCtx, &packet)>=0){// Is this a packet from the video stream?if(packet.stream_index==videoStream){// Decode video frameavcodec_decode_video(pCodecCtx, pFrame, &frameFinished,packet.data, packet.size);// Did we get a video frame?if(frameFinished){// Convert the image from its native format to RGB/*sws_scale(img_convert_ctx, 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);*/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);*/sws_scale(img_convert_ctx, 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);//Sleep(60);}}// Free the packet that was allocated by av_read_frameav_free_packet(&packet);SDL_PollEvent(&event);switch(event.type){case SDL_QUIT:SDL_Quit();exit(0);break;default: break;}};// Free the RGB imageav_free(buffer);//av_free(pFrameRGB);// Free the YUV frameav_free(pFrame);// Close the codecavcodec_close(pCodecCtx);// Close the video fileav_close_input_file(pFormatCtx); return 0;}