FFmpeg把MP4文件解码为YUV，然后通过SDL播放

#include <iostream>
extern "C"
{
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <SDL.h>
};
using namespace std;
//Refresh Event
#define SFM_REFRESH_EVENT  (SDL_USEREVENT + 1)
#define SFM_BREAK_EVENT  (SDL_USEREVENT + 2)
int thread_exit = 0;
int thread_pause = 0;

int sfp_refresh_thread(void *opaque)
{
    thread_exit = 0;
    thread_pause = 0;

    while (!thread_exit)
    {
        if (!thread_pause)
        {
            SDL_Event event;
            event.type = SFM_REFRESH_EVENT;
            SDL_PushEvent(&event);
        }
        SDL_Delay(10);
    }
    thread_exit = 0;
    thread_pause = 0;
    //Break
    SDL_Event event;
    event.type = SFM_BREAK_EVENT;
    SDL_PushEvent(&event);
    return 0;
}

int main(int argc, char* argv[])
{
    AVFormatContext *pFormatCtx;
    int             i, videoindex;
    AVCodecContext  *pCodecCtx;
    AVCodec         *pCodec;
    AVFrame *pFrame, *pFrameYUV;
    uint8_t *out_buffer;
    AVPacket *packet;
    int ret, got_picture;

    //------------SDL----------------
    int screen_w, screen_h;
    SDL_Window *screen;
    SDL_Renderer* sdlRenderer;
    SDL_Texture* sdlTexture;
    SDL_Rect sdlRect;
    SDL_Thread *video_tid;
    SDL_Event event;

    struct SwsContext *img_convert_ctx;

    char filepath[] = "test.mp4";

    av_register_all();
    avformat_network_init();
    pFormatCtx = avformat_alloc_context();

    if (avformat_open_input(&pFormatCtx, filepath, NULL, NULL) != 0)
    {
        printf("Couldn't open input stream.\n");
        return -1;
    }
    if (avformat_find_stream_info(pFormatCtx, NULL) < 0)
    {
        printf("Couldn't find stream information.\n");
        return -1;
    }
    videoindex = -1;
    for (i = 0; i < pFormatCtx->nb_streams; i++)
    {
        if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO)
        {
            videoindex = i;
            break;
        }
    }
    if (videoindex == -1)
    {
        printf("Didn't find a video stream.\n");
        return -1;
    }
    pCodecCtx = pFormatCtx->streams[videoindex]->codec;
    pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
    if (pCodec == NULL)
    {
        printf("Codec not found.\n");
        return -1;
    }
    if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0)
    {
        printf("Could not open codec.\n");
        return -1;
    }
    pFrame = av_frame_alloc();
    pFrameYUV = av_frame_alloc();
    out_buffer = (uint8_t *)av_malloc(avpicture_get_size(AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height));
    avpicture_fill((AVPicture *)pFrameYUV, out_buffer, AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height);

    //Output Info-----------------------------
    printf("---------------- File Information ---------------\n");
    av_dump_format(pFormatCtx, 0, filepath, 0);
    printf("-------------------------------------------------\n");

    img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);


    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER))
    {
        printf("Could not initialize SDL - %s\n", SDL_GetError());
        return -1;
    }
    //SDL 2.0 Support for multiple windows
    screen_w = pCodecCtx->width;
    screen_h = pCodecCtx->height;
    screen = SDL_CreateWindow("WS ffmpeg player", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 1280, 720, SDL_WINDOW_OPENGL);

    if (!screen)
    {
        printf("SDL: could not create window - exiting:%s\n", SDL_GetError());
        return -1;
    }
    sdlRenderer = SDL_CreateRenderer(screen, -1, 0);
    //IYUV: Y + U + V  (3 planes)
    //YV12: Y + V + U  (3 planes)
    sdlTexture = SDL_CreateTexture(sdlRenderer, SDL_PIXELFORMAT_IYUV, SDL_TEXTUREACCESS_STREAMING, pCodecCtx->width, pCodecCtx->height);

    sdlRect.x = 0;
    sdlRect.y = 0;
    sdlRect.w = screen_w;
    sdlRect.h = screen_h;

    packet = (AVPacket *)av_malloc(sizeof(AVPacket));

    video_tid = SDL_CreateThread(sfp_refresh_thread, NULL, NULL);
    //------------SDL End------------
    //Event Loop

    for (;;)
    {
        //Wait
        SDL_WaitEvent(&event);
        if (event.type == SFM_REFRESH_EVENT)
        {
            //------------------------------
            if (av_read_frame(pFormatCtx, packet) >= 0)
            {
                if (packet->stream_index == videoindex)
                {
                    ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);
                    if (ret < 0)
                    {
                        printf("Decode Error.\n");
                        return -1;
                    }
                    if (got_picture)
                    {
                        sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameYUV->data, pFrameYUV->linesize);
                        //SDL---------------------------
                        SDL_UpdateTexture(sdlTexture, NULL, pFrameYUV->data[0], pFrameYUV->linesize[0]);
                        SDL_RenderClear(sdlRenderer);
                        //SDL_RenderCopy( sdlRenderer, sdlTexture, &sdlRect, &sdlRect );  
                        SDL_RenderCopy(sdlRenderer, sdlTexture, NULL, NULL);
                        SDL_RenderPresent(sdlRenderer);
                        //SDL End-----------------------
                    }
                }
                av_free_packet(packet);
            }
            else
            {
                //Exit Thread
                thread_exit = 1;
            }
        }
        else if (event.type == SDL_KEYDOWN)
        {
            //Pause
            if (event.key.keysym.sym == SDLK_SPACE)
                thread_pause = !thread_pause;
        }
        else if (event.type == SDL_QUIT)
        {
            thread_exit = 1;
        }
        else if (event.type == SFM_BREAK_EVENT)
        {
            break;
        }
    }
    sws_freeContext(img_convert_ctx);
    SDL_Quit();
    //--------------
    av_frame_free(&pFrameYUV);
    av_frame_free(&pFrame);
    avcodec_close(pCodecCtx);
    avformat_close_input(&pFormatCtx);
    return getchar();
}