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./sdltutorialcn/blog/2013/01/25/sdl-2-dot-0-tutorial-index/
http://www./tutorials
ffmpeg的api文档可以在这里看:
http:///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 header
- if (avformat_open_input(&pFormatCtx, filepath, NULL, NULL) != 0){
- printf("Can't open the file\n");
- return -1;
- }
- //Retrieve stream information
- if (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 stream
- videoIndex = -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 stream
- pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
- if (pCodec == NULL){
- printf("Unsupported codec!\n");
- return -1;
- }
- //Open codec
- if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0){
- printf("Could not open codec.\n");
- return -1;
- }
- //allocate video frame and set its fileds to default value
- AVFrame *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 AVPicture
- avpicture_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 information
- cout << "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 stream
- while (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 picture
- ret = avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);
- //Did we get a video frame?
- if (ret >= 0){
- //Convert the image from its native format to YUV
- if (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;
- }
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