流程：
解复用->解码->yuv->交给纹理->交给渲染器->播放。
其中前三步使用ffmpeg实现，后三步用sdl实现。
#include <stdio.h> #include <SDL.h> #include <libavcodec/avcodec.h> #include <libavformat/avformat.h> #include <libswscale/swscale.h> // compatibility with newer API #if LIBAVCODEC_VERSION_INT < AV_VERSION_INT(55,28,1) #define av_frame_alloc avcodec_alloc_frame #define av_frame_free avcodec_free_frame #endif int main(int argc, char *argv[]) { int ret = -1; AVFormatContext *pFormatCtx = NULL; //for opening multi-media file int i, videoStream; AVCodecContext *pCodecCtxOrig = NULL; //codec context AVCodecContext *pCodecCtx = NULL; struct SwsContext *sws_ctx = NULL; AVCodec *pCodec = NULL; // the codecer AVFrame *pFrame = NULL; AVPacket packet; int frameFinished; float aspect_ratio; AVPicture *pict = NULL; SDL_Rect rect; Uint32 pixformat; //for render SDL_Window *win = NULL; SDL_Renderer *renderer = NULL; SDL_Texture *texture = NULL; //set defualt size of window int w_width = 640; int w_height = 480; if(argc < 2) { //fprintf(stderr, "Usage: command <file>\n"); SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Usage: command <file>"); return ret; } if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) { //fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError()); SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Could not initialize SDL - %s\n", SDL_GetError()); return ret; } //Register all formats and codecs av_register_all(); // Open video file if(avformat_open_input(&pFormatCtx, argv[1], NULL, NULL)!=0){ SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to open video file!"); goto __FAIL; // Couldn't open file } // Retrieve stream information if(avformat_find_stream_info(pFormatCtx, NULL)<0){ SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to find stream infomation!"); goto __FAIL; // 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){ SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Din't find a video stream!"); goto __FAIL;// Didn't find a video stream } // Get a pointer to the codec context for the video stream pCodecCtxOrig=pFormatCtx->streams[videoStream]->codec; // Find the decoder for the video stream pCodec=avcodec_find_decoder(pCodecCtxOrig->codec_id); if(pCodec==NULL) { SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Unsupported codec!\n"); goto __FAIL; // Codec not found } // Copy context pCodecCtx = avcodec_alloc_context3(pCodec); if(avcodec_copy_context(pCodecCtx, pCodecCtxOrig) != 0) { SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't copy codec context"); goto __FAIL;// Error copying codec context } // Open codec if(avcodec_open2(pCodecCtx, pCodec, NULL)<0) { SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to open decoder!\n"); goto __FAIL; // Could not open codec } // Allocate video frame pFrame=av_frame_alloc(); w_width = pCodecCtx->width; w_height = pCodecCtx->height; win = SDL_CreateWindow( "Media Player", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, w_width, w_height, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE); if(!win){ SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to create window by SDL"); goto __FAIL; } renderer = SDL_CreateRenderer(win, -1, 0); if(!renderer){ SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Failed to create Renderer by SDL"); goto __FAIL; } pixformat = SDL_PIXELFORMAT_IYUV; texture = SDL_CreateTexture(renderer, pixformat, SDL_TEXTUREACCESS_STREAMING, w_width, w_height); // initialize SWS context for software scaling sws_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_YUV420P, SWS_BILINEAR, NULL, NULL, NULL ); pict = (AVPicture*)malloc(sizeof(AVPicture)); avpicture_alloc(pict, AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height); // Read frames and save first five frames to disk 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) { // 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_UpdateYUVTexture(texture, NULL, pict->data[0], pict->linesize[0], pict->data[1], pict->linesize[1], pict->data[2], pict->linesize[2]); // Set Size of Window rect.x = 0; rect.y = 0; rect.w = pCodecCtx->width; rect.h = pCodecCtx->height; SDL_RenderClear(renderer); SDL_RenderCopy(renderer, texture, NULL, &rect); SDL_RenderPresent(renderer); } } // Free the packet that was allocated by av_read_frame av_free_packet(&packet); /* SDL_Event event; SDL_PollEvent(&event); switch(event.type) { case SDL_QUIT: goto __QUIT; break; default: break; } */ } __QUIT: ret = 0; __FAIL: // Free the YUV frame if(pFrame){ av_frame_free(&pFrame); } // Close the codec if(pCodecCtx){ avcodec_close(pCodecCtx); } if(pCodecCtxOrig){ avcodec_close(pCodecCtxOrig); } // Close the video file if(pFormatCtx){ avformat_close_input(&pFormatCtx); } if(pict){ avpicture_free(pict); free(pict); } if(win){ SDL_DestroyWindow(win); } if(renderer){ SDL_DestroyRenderer(renderer); } if(texture){ SDL_DestroyTexture(texture); } SDL_Quit(); return ret; }
