ffmpeg+sdl2.0编写最简单的视频播放器

花了好几天的时间，终于把这东东搞出来了

sdl2相比sdl1，api有了比较大的变化，尤其是绘图方面

网上基本上找不到用sdl2编写的，只好自己不断探索尝试

ffmpeg和sdl都可以直接去官网下载，现在已经有编译好的vc库文件下载，怎么配置网上有很多，这里就不多说了

推荐几个sdl2的教程：

http://adolfans.github.io/sdltutorialcn/blog/2013/01/25/sdl-2-dot-0-tutorial-index/

http://www.sdltutorials.com/tutorials

ffmpeg的api文档可以在这里看：

http://ffmpeg.org/doxygen/2.0/index.html

需要注意的一点是，建立工程的时候最好选择 控制台应用程序，加上预编译头文件，即有stdafx.h头文件的那种

再推荐一个学习的博客，我的代码就是参考他的写出来的

http://blog.csdn.net/leixiaohua1020/article/details/8652605

还有一个很好的教程，虽然有点过时，但是基本思想是不变的，很值得参考

如何用FFmpeg编写一个简单播放器

最后你需要了解一下像素格式，可以参考：

图文详解YUV格式

在sdl的头文件SDL_Pixel.h中有各种像素格式的声明

其他不多说了，直接上代码

#include "stdafx.h"extern "C"{#include "libavcodec\avcodec.h"#include "libavformat\avformat.h"#include "libswscale\swscale.h"}#include "SDL.h"#include "SDL_image.h"#include "SDL_thread.h"#include <iostream>using namespace std;/*void SaveFrame(AVFrame *pFrame, int width, int height, int iFrame){FILE *pFile;char szFilename[32];int y;sprintf(szFilename, "frame%d.ppm", iFrame);pFile = fopen(szFilename, "wb");if (pFile == NULL){cout << "open file:" << szFilename << " error." << endl;return;}//Write header}*/int _tmain(int argc, char *agrv[]){av_register_all();//注册了所有的文件格式和编解码的库，它们将被自动的使用在被打开的合适格式的文件上AVFormatContext *pFormatCtx;pFormatCtx = avformat_alloc_context();char filepath[] = "../../resource/test.mp4";//Open an input stream and read the headerif (avformat_open_input(&pFormatCtx, filepath, NULL, NULL) != 0){printf("Can't open the file\n");return -1;}//Retrieve stream informationif (avformat_find_stream_info(pFormatCtx, NULL) < 0){printf("Couldn't find stream information.\n");return -1;}int i, videoIndex;AVCodecContext *pCodecCtx;AVCodec *pCodec;//Find the first video streamvideoIndex = -1;for (i = 0; i < pFormatCtx->nb_streams; i++){//视音频流的个数if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO){videoIndex = i;break;}}if (videoIndex == -1)return -1;//Get a pointer to the codec context for the video stream//流中关于编解码器的信息就是被我们叫做"codec context"（编解码器上下文）//的东西。这里面包含了流中所使用的关于编解码器的所有信pCodecCtx = pFormatCtx->streams[videoIndex]->codec;//Find the decoder for the video streampCodec = avcodec_find_decoder(pCodecCtx->codec_id);if (pCodec == NULL){printf("Unsupported codec!\n");return -1;}//Open codecif (avcodec_open2(pCodecCtx, pCodec, NULL) < 0){printf("Could not open codec.\n");return -1;}//allocate video frame and set its fileds to default valueAVFrame *pFrame, *pFrameYUV;pFrame = av_frame_alloc();pFrameYUV = av_frame_alloc();//即使我们申请了一帧的内存，当转换的时候，我们仍然需要一个地方来放置原始//的数据。我们使用avpicture_get_size 来获得我们需要的大小， 然后手工申请//内存空间：uint8_t *out_buffer;int numBytes;numBytes = avpicture_get_size(PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height);//av_malloc 是ffmpeg 的malloc，用来实现一个简单的malloc 的包装，这样来保//证内存地址是对齐的（4 字节对齐或者2 字节对齐）。它并不能保 护你不被内//存泄漏，重复释放或者其它malloc 的问题所困扰。out_buffer = (uint8_t *)av_malloc(numBytes*sizeof(uint8_t));//Assign appropriate parts of buffer to image planes in pFrameYUV//Note that pFrameYUV is an AVFrame, but AVFrame is a superset of AVPictureavpicture_fill((AVPicture*)pFrameYUV, out_buffer, PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height);//----------------SDL--------------------------------------//if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)){printf("Could not initialize SDL -%s\n", SDL_GetError());exit(1);}SDL_Window *window = nullptr;window = SDL_CreateWindow("MyPlayer", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,pCodecCtx->width, pCodecCtx->height, SDL_WINDOW_SHOWN);if (!window){cout << SDL_GetError() << endl;return 1;}SDL_Renderer *ren = nullptr;ren = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);if (ren == nullptr){cout << SDL_GetError() << endl;return -1;}SDL_Texture *texture = nullptr;texture = SDL_CreateTexture(ren, SDL_PIXELFORMAT_YV12,SDL_TEXTUREACCESS_STREAMING, pCodecCtx->width, pCodecCtx->height);SDL_Rect rect;rect.x = 0, rect.y = 0;rect.w = pCodecCtx->width;rect.h = pCodecCtx->height;//*************************************************************////通过读取包来读取整个视频流，然后把它解码成帧，最后转换格式并且保存int frameFinished;//int psize = pCodecCtx->width * pCodecCtx->height;AVPacket packet;av_new_packet(&packet, numBytes);//output file informationcout << "文件信息----------------------------------" << endl;av_dump_format(pFormatCtx, 0, filepath, 0);cout << "--------------------------------------------" << endl;i = 0;int ret;static struct SwsContext *img_convert_ctx;img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height,pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, PIX_FMT_YUV420P,SWS_BICUBIC, NULL, NULL, NULL);//Read the next frame of a streamwhile (av_read_frame(pFormatCtx, &packet) >= 0){//Is this a packet from the video stream?if (packet.stream_index == videoIndex){//decode video frame of size packet.size from packet.data into pictureret = avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);//Did we get a video frame?if (ret >= 0){//Convert the image from its native format to YUVif (frameFinished){sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data,pFrame->linesize, 0, pCodecCtx->height, pFrameYUV->data, pFrameYUV->linesize);SDL_UpdateYUVTexture(texture, &rect, pFrameYUV->data[0], pFrameYUV->linesize[0],pFrameYUV->data[1], pFrameYUV->linesize[1], pFrameYUV->data[2], pFrameYUV->linesize[2]);SDL_RenderClear(ren);SDL_RenderCopy(ren, texture, &rect, &rect);SDL_RenderPresent(ren);}SDL_Delay(50);}else{cout << "decode error" << endl;return -1;}}}av_free_packet(&packet);SDL_Event event;SDL_PollEvent(&event);switch (event.type){case SDL_QUIT:SDL_Quit();exit(0);break;default:break;}SDL_DestroyTexture(texture);av_frame_free(&pFrame);av_frame_free(&pFrameYUV);avcodec_close(pCodecCtx);avformat_close_input(&pFormatCtx);return 0;}