FFmpeg 开发笔记（中级）

FFmpeg中H264 解码 &FFmpeg中H264 编码
步骤：找到解码器 -> 打开解码器-> 解码

• AVCodec 编码器结构体
• AVCodecContext编码器上下文
• AVFrame解码后的帧

av_frame_alloc/av_frame_free() //创建frame /释放frame
avcodec_alloc_context3() //分配编解码器avcodec 上下文
avcodec_free_context3() //释放编解码器avcodec 上下文
avcodec_find_decoder() //查找解码器
avcodec_open2() //打开解码器
avcodec_decoder_video2() //解码（将解码的数据变成未压缩的数据）

avcodec_find_encoder_by_name //查找编码器-通过名字
avcodec_open2() //设置编码参数，并打开编解码器(同解码)
avcodec_encode_video2() //编码

程序内容：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <libavcodec/avcodec.h>
#include <libavutil/opt.h>
#include <libavutil/imgutils.h>

int main(int argc, char **argv)
{
    const char *filename, *codec_name;
    const AVCodec *codec;
    AVCodecContext *c= NULL;
    int i, ret, x, y, got_output;
    FILE *f;
    AVFrame *frame;
    AVPacket pkt;
    /* */
    uint8_t endcode[] = { 0, 0, 1, 0xb7 };

    if (argc <= 2) {
        fprintf(stderr, "Usage: %s <output file> <codec name>\n", argv[0]);
        exit(0);
    }
    filename = argv[1];
    codec_name = argv[2];

    avcodec_register_all();

    /* 通过输入的解码器名字找到对应的code解码器 */
    codec = avcodec_find_encoder_by_name(codec_name);
    if (!codec) {
        fprintf(stderr, "Codec not found\n");
        exit(1);
    }
    
    /*通过codec 创建codec 的上下文*/
    c = avcodec_alloc_context3(codec);
    if (!c) {
        fprintf(stderr, "Could not allocate video codec context\n");
        exit(1);
    }

    /* 设置码率 */
    c->bit_rate = 400000;
    /* 视频宽/高 */
    c->width = 352;
    c->height = 288;
    /* 时间基（1/25） */
    c->time_base = (AVRational){1, 25};
    /* 帧率（一秒钟25）*/
    c->framerate = (AVRational){25, 1};

    /* 10帧出现一个关键帧（值越大，码率越小，关键帧丢后需要等待的时间较长）*/
    c->gop_size = 10;
    /* 设置B帧参数（）*/
    c->max_b_frames = 1;
    /* 设置图像的编码格式YUV420P*/
    c->pix_fmt = AV_PIX_FMT_YUV420P;

    if (codec->id == AV_CODEC_ID_H264){
        /* 如果编码器是h264--采用压缩速度慢的，视频质量较高*/
        av_opt_set(c->priv_data, "preset", "slow", 0);
    }

    /* open it */
    if (avcodec_open2(c, codec, NULL) < 0) {
        fprintf(stderr, "Could not open codec\n");
        exit(1);
    }

    f = fopen(filename, "wb");
    if (!f) {
        fprintf(stderr, "Could not open %s\n", filename);
        exit(1);
    }

    frame = av_frame_alloc();
    if (!frame) {
        fprintf(stderr, "Could not allocate video frame\n");
        exit(1);
    }
    /**/
    frame->format = c->pix_fmt;
    frame->width  = c->width;
    frame->height = c->height;

    ret = av_frame_get_buffer(frame, 32);
    if (ret < 0) {
        fprintf(stderr, "Could not allocate the video frame data\n");
        exit(1);
    }


    /* 此处人工造了一个一秒的YUV数据 */
    for (i = 0; i < 25; i++) {
        av_init_packet(&pkt);
        pkt.data = NULL;    // packet data will be allocated by the encoder
        pkt.size = 0;
        /* */
        fflush(stdout);

        /* make sure the frame data is writable */
        ret = av_frame_make_writable(frame);
        if (ret < 0)
            exit(1);

        /* prepare a dummy image */
        /* Y */
        for (y = 0; y < c->height; y++) {
            for (x = 0; x < c->width; x++) {
                frame->data[0][y * frame->linesize[0] + x] = x + y + i * 3;
            }
        }

        /* Cb and Cr */
        for (y = 0; y < c->height/2; y++) {
            for (x = 0; x < c->width/2; x++) {
                frame->data[1][y * frame->linesize[1] + x] = 128 + y + i * 2;
                frame->data[2][y * frame->linesize[2] + x] = 64 + x + i * 5;
            }
        }

        frame->pts = i;

        /* encode the image */
        ret = avcodec_encode_video2(c, &pkt, frame, &got_output);
        if (ret < 0) {
            fprintf(stderr, "Error encoding frame\n");
            exit(1);
        }
        /* 如果唯一，则写入文件*/
        if (got_output) {
            printf("Write frame %3d (size=%5d)\n", i, pkt.size);
            fwrite(pkt.data, 1, pkt.size, f);
            av_packet_unref(&pkt);
        }
    }

    /* get the delayed frames */
    for (got_output = 1; got_output; i++) {
        fflush(stdout);

        ret = avcodec_encode_video2(c, &pkt, NULL, &got_output);
        if (ret < 0) {
            fprintf(stderr, "Error encoding frame\n");
            exit(1);
        }

        if (got_output) {
            printf("Write frame %3d (size=%5d)\n", i, pkt.size);
            fwrite(pkt.data, 1, pkt.size, f);
            av_packet_unref(&pkt);
        }
    }

    /* add sequence end code to have a real MPEG file */
    fwrite(endcode, 1, sizeof(endcode), f);
    fclose(f);

    avcodec_free_context(&c);
    av_frame_free(&frame);

    return 0;
}

使用命令编译：
clang -g -o encode_video encode_video.c pkg-config --libs libavcodec
运行程序：
./encode_video output1.h264 libx264
ffplay output1.h264

FFmpeg视频转图片实例
程序内容：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <libavformat/avformat.h>
#include <libavcodec/avcodec.h>
#include <libswscale/swscale.h>


int main (int argc, char *argv[]){
    int ret;
    const char *filename, *outfilename;
    AVFormatContext *fmt_ctx = NULL;
    const AVCodec *codec;
    AVCodecContext *codec_context = NULL;
    AVStream *stream = NULL;
    int stream_index;
    int frame_count;
    AVFrame *frame;
    struct SwsContext *img_convert_ctx;
    AVPacket *av_pkt;

    if (argc <=2 ){
        fprintf(stderr,"input less two params");
        exit(0);
    }
    filename = argv[1];
    outfilename = argv[2];

    av_register_all();
    if (avformat_open_input(&fmt_ctx,filename,NULL,NULL)<0){
        fprintf(stderr,"could not open file %s",filename);
        exit(1);
    }

    if(avformat_find_stream_info(fmt_ctx,NULL)<0){
        fprintf(stderr,"Could not find stream information n");
        exit(1);
    }
    /*打印视频信息*/
    av_dump_format(fmt_ctx,0,filename,0);
    av_init_packet(&av_pkt);

    ret = av_find_best_stream(fmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);
    if (ret<0){
        fprintf(stderr,"Could not find %s stream in input file %s",av_get_media_type_string(AVMEDIA_TYPE_VIDEO),filename);
        return ret;
    }

    stream_index = ret;
    stream = fmt_ctx->streams[stream_index];

    /* codecpar->编解码参数集合*/
    codec = avcodec_find_decoder(stream->codecpar->codec_id);
    if(!codec){
        fprintf(stderr,"Fail to find %s codec\n",av_get_media_type_string(AVDEMID_TYPE_VIDEO));
        return AVERROR(EINVAL);
    }
    codec_context = avcodec_alloc_context3(NULL);
    if(!codec_context){
        fprintf(stderr,"Cound not allocate video codec context \n");
        /* exit(1)表示异常退出，exit(0)表示正常退出*/
        exit(1);
    }

    /*拷贝流的参数到 avcode context */
    if((ret = avcodec_parameters_to_context(codec_context,stream->codecpar))<0){
        fprintf(stderr,"Failed to copy %s codec parameters to decoder context \n",av_get_media_type_string(AVMEDIA_TYPE_VIDEO));
        return ret;
    }

    if (avcodec_open2(codec_context,codec, NULL)<0){
        fprintf(sdderr,"Could not open codec");
        exit(1);
    }

    img_convert_ctx = sws_getContext( codec_context->width,codec_context->height,
                                        codec_context->pix_fmt,
                                        codec_context->width,codec_context->height,
                                        AV_PIX_FMT_RGB24,
                                        SWS_BICUBIC,NULL,NULL,NULL);
    if (img_convert_ctx == NULL){
        fprintf(stderr,"cannot initialize the conversion context \n");
        exit(1);
    }
    frame = av_frame_alloc();
    if(!frame){
        fprintf(stderr,"fail allocate video frame \n");
        exit(1);
    }
    while(av_read_frame(fmt_ctx,&av_pkt)>=0){
        if(av_pkt.stream_index == stream_index){
            if(decode_write_frame(outfilename, codec_context, img_convert_ctx, frame, &frame_count, &av_pkt,0)<0 ){
                exit(1);
            }
        }
        av_packet_unref(&av_pkt);
    }

    return 0;
}

static int decode_write_frame(const char *outfilename, AVCodecContext *avctx, struct SwsContext *img_convert_ctx, AVFrame *frame, int *frame_count, AVPacket *pkt, int last){
    int len ,got_frame;
    char buf[1024];
    len = avcodec_decode_video2(avctx, frame, &got_frame, pkt);
    if(len<0){
        fprintf(stderr,"error while decoding frame %d \n",*frame_count);
        return len;
    }
    /* 如果got_frame >0 说明解码成功*/
    if(got_frame){
        fprintf(stderr,"saving %s frame %3d\n",last?"last":"", *frame_count);
        /**/
        fflush(stdout);
        snprintf(buf,sizeof(buf),"%s -%d.bmp",outfilename,*frame_count);
        saveBMP(img_convert_ctx,frame,buf);
        (*frame_count)++;
    }
    if(pkt->data) {
        pkt->size -= len;
        pkt->data += len;
    }
    return 0;
}

使用命令编译：

运行程序：

FFmpeg中的AAC 编码&FFmpeg中的 AAC 解码

程序内容：

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <libavcodec/avcodec.h>
#include <libavutil/channel_layout.h>
#include <libavutil/common.h>
#include <libavutil/frame.h>
#include <libavutil/samplefmt.h>

/* check that a given sample format is supported by the encoder */
static int check_sample_fmt(const AVCodec *codec, enum AVSampleFormat sample_fmt)
{
    const enum AVSampleFormat *p = codec->sample_fmts;

    while (*p != AV_SAMPLE_FMT_NONE) {
        if (*p == sample_fmt)
            return 1;
        p++;
    }
    return 0;
}

/* just pick the highest supported samplerate */
static int select_sample_rate(const AVCodec *codec)
{
    const int *p;
    int best_samplerate = 0;

    if (!codec->supported_samplerates)
        return 44100;

    p = codec->supported_samplerates;
    while (*p) {
        if (!best_samplerate || abs(44100 - *p) < abs(44100 - best_samplerate))
            best_samplerate = *p;
        p++;
    }
    return best_samplerate;
}

/* select layout with the highest channel count */
static int select_channel_layout(const AVCodec *codec)
{
    const uint64_t *p;
    uint64_t best_ch_layout = 0;
    int best_nb_channels   = 0;

    if (!codec->channel_layouts)
        return AV_CH_LAYOUT_STEREO;

    p = codec->channel_layouts;
    while (*p) {
        int nb_channels = av_get_channel_layout_nb_channels(*p);

        if (nb_channels > best_nb_channels) {
            best_ch_layout    = *p;
            best_nb_channels = nb_channels;
        }
        p++;
    }
    return best_ch_layout;
}

int main(int argc, char **argv)
{
    const char *filename;
    const AVCodec *codec;
    AVCodecContext *c= NULL;
    AVFrame *frame;
    AVPacket pkt;
    int i, j, k, ret, got_output;
    FILE *f;
    uint16_t *samples;
    float t, tincr;

    if (argc <= 1) {
        fprintf(stderr, "Usage: %s <output file>\n", argv[0]);
        return 0;
    }
    filename = argv[1];

    avcodec_register_all();

    /* find the MP2 encoder */
    codec = avcodec_find_encoder(AV_CODEC_ID_MP2);
    if (!codec) {
        fprintf(stderr, "Codec not found\n");
        exit(1);
    }

    c = avcodec_alloc_context3(codec);
    if (!c) {
        fprintf(stderr, "Could not allocate audio codec context\n");
        exit(1);
    }

    /* put sample parameters */
    c->bit_rate = 64000;

    /* check that the encoder supports s16 pcm input */
    c->sample_fmt = AV_SAMPLE_FMT_S16;
    if (!check_sample_fmt(codec, c->sample_fmt)) {
        fprintf(stderr, "Encoder does not support sample format %s",
                av_get_sample_fmt_name(c->sample_fmt));
        exit(1);
    }

    /* 设置采样率/声道类型/通道个数 */
    c->sample_rate    = select_sample_rate(codec);
    c->channel_layout = select_channel_layout(codec);
    c->channels       = av_get_channel_layout_nb_channels(c->channel_layout);

    /* 打开编码器 */
    if (avcodec_open2(c, codec, NULL) < 0) {
        fprintf(stderr, "Could not open codec\n");
        exit(1);
    }

    f = fopen(filename, "wb");
    if (!f) {
        fprintf(stderr, "Could not open %s\n", filename);
        exit(1);
    }

    /* frame containing input raw audio */
    frame = av_frame_alloc();
    if (!frame) {
        fprintf(stderr, "Could not allocate audio frame\n");
        exit(1);
    }

    frame->nb_samples     = c->frame_size;
    frame->format         = c->sample_fmt;
    frame->channel_layout = c->channel_layout;

    /* allocate the data buffers */
    ret = av_frame_get_buffer(frame, 0);
    if (ret < 0) {
        fprintf(stderr, "Could not allocate audio data buffers\n");
        exit(1);
    }

    /* 伪造假数据（实际身影是麦克风采集获取） */
    t = 0;
    tincr = 2 * M_PI * 440.0 / c->sample_rate;
    for (i = 0; i < 200; i++) {
        av_init_packet(&pkt);
        pkt.data = NULL; // packet data will be allocated by the encoder
        pkt.size = 0;

        /* make sure the frame is writable -- makes a copy if the encoder
         * kept a reference internally */
        ret = av_frame_make_writable(frame);
        if (ret < 0)
            exit(1);
        samples = (uint16_t*)frame->data[0];

        for (j = 0; j < c->frame_size; j++) {
            samples[2*j] = (int)(sin(t) * 10000);

            for (k = 1; k < c->channels; k++)
                samples[2*j + k] = samples[2*j];
            t += tincr;
        }
        /* encode the samples */
        ret = avcodec_encode_audio2(c, &pkt, frame, &got_output);
        if (ret < 0) {
            fprintf(stderr, "Error encoding audio frame\n");
            exit(1);
        }
        if (got_output) {
            fwrite(pkt.data, 1, pkt.size, f);
            av_packet_unref(&pkt);
        }
    }

    /* get the delayed frames */
    for (got_output = 1; got_output; i++) {
        ret = avcodec_encode_audio2(c, &pkt, NULL, &got_output);
        if (ret < 0) {
            fprintf(stderr, "Error encoding frame\n");
            exit(1);
        }
        /* 有时是多次循环才会生成一个packet，通过got_output 参数获取是否生成了一个包数据（从而写入文件）*/
        if (got_output) {
            fwrite(pkt.data, 1, pkt.size, f);
            av_packet_unref(&pkt);
        }
    }
    fclose(f);

    av_frame_free(&frame);
    avcodec_free_context(&c);

    return 0;
}

使用命令编译：
clang -g -o encode_audio encode_audio.c pkg-config --libs libavcodec

运行程序：
./encode_audio 2.aac

SDL窗口渲染（查看之前笔记）

FFmpeg实现PCM 播放器

前提该要：之前有将mp4 文件提取出pcm 音频数据的命令如下
ffmpeg -i input.mp4 -vn -ar 44100 -ac 2 -f s16le out.pcm

程序内容：

#include <stdio.h>
#include <SDL.h>


/* 4M空间*/
#define BLOCK_SIZE 4096000

static Uint8 *audio_buf = NULL;
static Uint8 *audio_pos = NULL;
static size_t buffer_len = 0;

/*
udata = 需要传回的参数
stream = 需要播放的buffer地址
len = 需要的长度
*/
void read_audio_data(void *udata, Uint8 *stream, int len){

    if(buffer_len == 0){
        return;
    }

    /*清除缓冲区数据 设为0*/
    SDL_memset(stream, 0, len);
    /* 判断缓冲区 buffer_len 和传进来的数据长度len 进行对比，不大于缓冲区长度即可（防止越界） */
    len = (len < buffer_len) ? len : buffer_len;
    /* 
    stream = 
    audio_pos = 数据起始位
    len = 数据长度
    SDL_MixAudio(stream, audio_pos, len, SDL_MIX_MAXVOLUME);
    /*audio_pos 位置移动 len 长度（移动播放的数据长度）*/
    audio_pos += len;
    /*buffer_len 减少 len 长度（消耗掉的数据长度）*/
    buffer_len -= len;
}


int main(int argc, char *argv[])
{
    int ret = -1;

    FILE *audio_fd = NULL;

    SDL_AudioSpec spec;

    char *path = "./test.pcm";

    //SDL initialize
    if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)){
        fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError());
        return ret;
    }

    //open pcm file
    audio_fd = fopen(path, "r");
    if(!audio_fd){
        fprintf(stderr, "Failed to open pcm file!\n");
        goto __FAIL;
    }

    //alloc memory for audio
    audio_buf = (Uint8*)malloc(BLOCK_SIZE);
    if(!audio_buf){
        goto __FAIL;
    }

    /*
    freq = 采样率
    format = 采样格式
    channels = 通道数
    silence = 
    samples = 
    callback = 回调函数
    userdata = 回调参数
    */
    spec.freq = 44100;;
    spec.format = AUDIO_S16SYS;
    spec.channels = 2;
    spec.silence = 0;
    spec.samples = 2048;;
    spec.callback = read_audio_data;;
    spec.userdata = NULL;

    //spec 是常用的音频参数（只有返回0 的时候才表示成功）
    if(SDL_OpenAudio(&spec, NULL)){
        fprintf(stderr, "Failed to open audio device, %s\n", SDL_GetError());
        goto __FAIL;
    }

    //play audio （0 表示播放、1表示暂停）
    SDL_PauseAudio(0);

    do{
        //read data from pcm file
        /* 读取BLOCK_Size大小的数据到audio_buf */
        buffer_len = fread(audio_buf, 1, BLOCK_SIZE, audio_fd);
        fprintf(stderr, "block size is %zu\n", buffer_len);

        audio_pos = audio_buf;

        //the main thread wait for a moment
        /* 让audio_buf 消耗，消耗完了，从新堵一个BLOCK_SIZE 大小的数据*/
        while(audio_pos < (audio_buf + buffer_len)) {
            /*延迟执行 1ms */
            SDL_Delay(1);
        }

    }while(buffer_len !=0);

    //关闭音频设备
    SDL_CloseAudio();

    ret = 0;

__FAIL:
    //release some resources
    if(audio_buf){
        free(audio_buf);
    }

    if(audio_fd){
        fclose(audio_fd);
    }

    //quit SDL
    SDL_Quit();
    return ret;
}






使用命令编译: clang -g -o pcm_player pcm_player.c `pkg-config --cflags --libs sdl2`
运行程序:   ./pcm_player

FFmpeg实现最简单的播放器

程序内容：

#include <SDL.h>
#include <stdio.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;
  /* 图像裁剪的上下文*/
  struct SwsContext *sws_ctx = NULL;

  AVCodec         *pCodec = NULL; // the codecer
  AVFrame         *pFrame = NULL;
  AVPacket        packet;

  int             frameFinished;
  float           aspect_ratio;

  /* 存放YUV数据的AVPicture 结构体*/
  AVPicture     *pict  = NULL;
  /*渲染大小*/
  SDL_Rect        rect;
  Uint32    pixformat; 

  /* 渲染窗口*/
  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;

  /* 创建SDL窗口
  SDL_WINDOW_OPENGL 使用openGL
  SDL_WINDOW_RESIZABLE 窗口可大可小
  */
  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;
  }

  /* 创建渲染器*/
  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;
  /*
  pixformat = 像素格式
  SDL_TEXTUREACCESS_STREAMING = 纹理格式（不断更新的视频流） */
  texture = SDL_CreateTexture(renderer,
        pixformat, 
        SDL_TEXTUREACCESS_STREAMING,
        w_width, 
        w_height);

  // initialize SWS context for software scaling
  /* 
  对图像进行裁剪(此处没有裁剪)
  */
  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;
}

使用命令编译:
clang -g -o player2 player2.c pkg-config --cflags --libs sdl2 libavformat libavutil libswscale
运行程序:
./player2 input.mp4

FFmpeg播放器多线程版

程序内容：

#include <stdio.h>
#include <assert.h>
#include <math.h>

#include <SDL.h>

#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libswresample/swresample.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

#define SDL_AUDIO_BUFFER_SIZE 1024
#define MAX_AUDIO_FRAME_SIZE 192000 //channels(2) * data_size(2) * sample_rate(48000)

#define MAX_AUDIOQ_SIZE (5 * 16 * 1024)
#define MAX_VIDEOQ_SIZE (5 * 256 * 1024)

#define AV_SYNC_THRESHOLD 0.01
#define AV_NOSYNC_THRESHOLD 10.0

#define SAMPLE_CORRECTION_PERCENT_MAX 10
#define AUDIO_DIFF_AVG_NB 20

#define FF_REFRESH_EVENT (SDL_USEREVENT)
#define FF_QUIT_EVENT (SDL_USEREVENT + 1)

#define VIDEO_PICTURE_QUEUE_SIZE 1

#define DEFAULT_AV_SYNC_TYPE AV_SYNC_AUDIO_MASTER //AV_SYNC_VIDEO_MASTER

typedef struct PacketQueue {
  AVPacketList *first_pkt, *last_pkt;
  int nb_packets;
  int size;
  SDL_mutex *mutex;
  SDL_cond *cond;
} PacketQueue;


typedef struct VideoPicture {
  AVPicture *bmp;
  int width, height; /* source height & width */
  int allocated;
  double pts;
} VideoPicture;

typedef struct VideoState {

  //multi-media file
  char            filename[1024];
  AVFormatContext *pFormatCtx;
  int             videoStream, audioStream;

  //sync
  int             av_sync_type;
  double          external_clock; /* external clock base */
  int64_t         external_clock_time;

  double          audio_diff_cum; /* used for AV difference average computation */
  double          audio_diff_avg_coef;
  double          audio_diff_threshold;
  int             audio_diff_avg_count;

  double          audio_clock;
  double          frame_timer;
  double          frame_last_pts;
  double          frame_last_delay;

  double          video_clock; ///<pts of last decoded frame / predicted pts of next decoded frame
  double          video_current_pts; ///<current displayed pts (different from video_clock if frame fifos are used)
  int64_t         video_current_pts_time;  ///<time (av_gettime) at which we updated video_current_pts - used to have running video pts

  //audio
  AVStream        *audio_st;
  AVCodecContext  *audio_ctx;
  PacketQueue     audioq;
  uint8_t         audio_buf[(MAX_AUDIO_FRAME_SIZE * 3) / 2];
  unsigned int    audio_buf_size;
  unsigned int    audio_buf_index;
  AVFrame         audio_frame;
  AVPacket        audio_pkt;
  uint8_t         *audio_pkt_data;
  int             audio_pkt_size;
  int             audio_hw_buf_size;

  //video
  AVStream        *video_st;
  AVCodecContext  *video_ctx;
  PacketQueue     videoq;
  struct SwsContext *video_sws_ctx;
  struct SwrContext *audio_swr_ctx;

  VideoPicture    pictq[VIDEO_PICTURE_QUEUE_SIZE];
  int             pictq_size, pictq_rindex, pictq_windex;
  SDL_mutex       *pictq_mutex;
  SDL_cond        *pictq_cond;
  
  SDL_Thread      *parse_tid;
  SDL_Thread      *video_tid;

  int             quit;
} VideoState;

SDL_mutex    *text_mutex;
SDL_Window   *win = NULL;
SDL_Renderer *renderer;
SDL_Texture  *texture;

enum {
  AV_SYNC_AUDIO_MASTER,
  AV_SYNC_VIDEO_MASTER,
  AV_SYNC_EXTERNAL_MASTER,
};

FILE *yuvfd = NULL;
FILE *audiofd = NULL;

/* Since we only have one decoding thread, the Big Struct
   can be global in case we need it. */
VideoState *global_video_state;

void packet_queue_init(PacketQueue *q) {
  memset(q, 0, sizeof(PacketQueue));
  q->mutex = SDL_CreateMutex();
  q->cond = SDL_CreateCond();
}
int packet_queue_put(PacketQueue *q, AVPacket *pkt) {

  AVPacketList *pkt1;
  if(av_dup_packet(pkt) < 0) {
    return -1;
  }
  pkt1 = av_malloc(sizeof(AVPacketList));
  if (!pkt1)
    return -1;
  pkt1->pkt = *pkt;
  pkt1->next = NULL;
  
  SDL_LockMutex(q->mutex);

  if (!q->last_pkt)
    q->first_pkt = pkt1;
  else
    q->last_pkt->next = pkt1;
  q->last_pkt = pkt1;
  q->nb_packets++;
  q->size += pkt1->pkt.size;
  SDL_CondSignal(q->cond);
  
  SDL_UnlockMutex(q->mutex);
  return 0;
}

int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block)
{
  AVPacketList *pkt1;
  int ret;

  SDL_LockMutex(q->mutex);
  
  for(;;) {
    
    if(global_video_state->quit) {
      ret = -1;
      break;
    }

    pkt1 = q->first_pkt;
    if (pkt1) {
      q->first_pkt = pkt1->next;
      if (!q->first_pkt)
  q->last_pkt = NULL;
      q->nb_packets--;
      q->size -= pkt1->pkt.size;
      *pkt = pkt1->pkt;
      av_free(pkt1);
      ret = 1;
      break;
    } else if (!block) {
      ret = 0;
      break;
    } else {
      SDL_CondWait(q->cond, q->mutex);
    }
  }
  SDL_UnlockMutex(q->mutex);
  return ret;
}

double get_audio_clock(VideoState *is) {
  double pts;
  int hw_buf_size, bytes_per_sec, n;
  
  pts = is->audio_clock; /* maintained in the audio thread */
  hw_buf_size = is->audio_buf_size - is->audio_buf_index;
  bytes_per_sec = 0;
  n = is->audio_ctx->channels * 2;
  if(is->audio_st) {
    bytes_per_sec = is->audio_ctx->sample_rate * n;
  }
  if(bytes_per_sec) {
    pts -= (double)hw_buf_size / bytes_per_sec;
  }
  return pts;
}
double get_video_clock(VideoState *is) {
  double delta;

  delta = (av_gettime() - is->video_current_pts_time) / 1000000.0;
  return is->video_current_pts + delta;
}
double get_external_clock(VideoState *is) {
  return av_gettime() / 1000000.0;
}

double get_master_clock(VideoState *is) {
  if(is->av_sync_type == AV_SYNC_VIDEO_MASTER) {
    return get_video_clock(is);
  } else if(is->av_sync_type == AV_SYNC_AUDIO_MASTER) {
    return get_audio_clock(is);
  } else {
    return get_external_clock(is);
  }
}


/* Add or subtract samples to get a better sync, return new
   audio buffer size */
int synchronize_audio(VideoState *is, short *samples,
          int samples_size, double pts) {
  int n;
  double ref_clock;

  n = 2 * is->audio_ctx->channels;
  
  if(is->av_sync_type != AV_SYNC_AUDIO_MASTER) {
    double diff, avg_diff;
    int wanted_size, min_size, max_size /*, nb_samples */;
    
    ref_clock = get_master_clock(is);
    diff = get_audio_clock(is) - ref_clock;

    if(diff < AV_NOSYNC_THRESHOLD) {
      // accumulate the diffs
      is->audio_diff_cum = diff + is->audio_diff_avg_coef
  * is->audio_diff_cum;
      if(is->audio_diff_avg_count < AUDIO_DIFF_AVG_NB) {
  is->audio_diff_avg_count++;
      } else {
  avg_diff = is->audio_diff_cum * (1.0 - is->audio_diff_avg_coef);
  if(fabs(avg_diff) >= is->audio_diff_threshold) {
    wanted_size = samples_size + ((int)(diff * is->audio_ctx->sample_rate) * n);
    min_size = samples_size * ((100 - SAMPLE_CORRECTION_PERCENT_MAX) / 100);
    max_size = samples_size * ((100 + SAMPLE_CORRECTION_PERCENT_MAX) / 100);
    if(wanted_size < min_size) {
      wanted_size = min_size;
    } else if (wanted_size > max_size) {
      wanted_size = max_size;
    }
    if(wanted_size < samples_size) {
      /* remove samples */
      samples_size = wanted_size;
    } else if(wanted_size > samples_size) {
      uint8_t *samples_end, *q;
      int nb;

      /* add samples by copying final sample*/
      nb = (samples_size - wanted_size);
      samples_end = (uint8_t *)samples + samples_size - n;
      q = samples_end + n;
      while(nb > 0) {
        memcpy(q, samples_end, n);
        q += n;
        nb -= n;
      }
      samples_size = wanted_size;
    }
  }
      }
    } else {
      /* difference is TOO big; reset diff stuff */
      is->audio_diff_avg_count = 0;
      is->audio_diff_cum = 0;
    }
  }
  return samples_size;
}

int audio_decode_frame(VideoState *is, uint8_t *audio_buf, int buf_size, double *pts_ptr) {

  int len1, data_size = 0;
  AVPacket *pkt = &is->audio_pkt;
  double pts;
  int n;


  for(;;) {
    while(is->audio_pkt_size > 0) {
      int got_frame = 0;
      len1 = avcodec_decode_audio4(is->audio_ctx, &is->audio_frame, &got_frame, pkt);
      if(len1 < 0) {
  /* if error, skip frame */
  is->audio_pkt_size = 0;
  break;
      }
      data_size = 0;
      if(got_frame) {
        /*
  data_size = av_samples_get_buffer_size(NULL, 
                 is->audio_ctx->channels,
                 is->audio_frame.nb_samples,
                 is->audio_ctx->sample_fmt,
                 1);
        */
        data_size = 2 * is->audio_frame.nb_samples * 2;
  assert(data_size <= buf_size);

        swr_convert(is->audio_swr_ctx,
                        &audio_buf,
                        MAX_AUDIO_FRAME_SIZE*3/2,
                        (const uint8_t **)is->audio_frame.data,
                        is->audio_frame.nb_samples);

        fwrite(audio_buf, 1, data_size, audiofd);
  //memcpy(audio_buf, is->audio_frame.data[0], data_size);
      }
      is->audio_pkt_data += len1;
      is->audio_pkt_size -= len1;
      if(data_size <= 0) {
  /* No data yet, get more frames */
  continue;
      }
      pts = is->audio_clock;
      *pts_ptr = pts;
      n = 2 * is->audio_ctx->channels;
      is->audio_clock += (double)data_size /
  (double)(n * is->audio_ctx->sample_rate);
      /* We have data, return it and come back for more later */
      return data_size;
    }
    if(pkt->data)
      av_free_packet(pkt);

    if(is->quit) {
      return -1;
    }
    /* next packet */
    if(packet_queue_get(&is->audioq, pkt, 1) < 0) {
      return -1;
    }
    is->audio_pkt_data = pkt->data;
    is->audio_pkt_size = pkt->size;
    /* if update, update the audio clock w/pts */
    if(pkt->pts != AV_NOPTS_VALUE) {
      is->audio_clock = av_q2d(is->audio_st->time_base)*pkt->pts;
    }
  }
}

void audio_callback(void *userdata, Uint8 *stream, int len) {

  VideoState *is = (VideoState *)userdata;
  int len1, audio_size;
  double pts;

  SDL_memset(stream, 0, len);

  while(len > 0) {
    if(is->audio_buf_index >= is->audio_buf_size) {
      /* We have already sent all our data; get more */
      audio_size = audio_decode_frame(is, is->audio_buf, sizeof(is->audio_buf), &pts);
      if(audio_size < 0) {
  /* If error, output silence */
  is->audio_buf_size = 1024 * 2 * 2;
  memset(is->audio_buf, 0, is->audio_buf_size);
      } else {
  audio_size = synchronize_audio(is, (int16_t *)is->audio_buf,
               audio_size, pts);
  is->audio_buf_size = audio_size;
      }
      is->audio_buf_index = 0;
    }
    len1 = is->audio_buf_size - is->audio_buf_index;
    if(len1 > len)
      len1 = len;
    SDL_MixAudio(stream,(uint8_t *)is->audio_buf + is->audio_buf_index, len1, SDL_MIX_MAXVOLUME);
    //memcpy(stream, (uint8_t *)is->audio_buf + is->audio_buf_index, len1);
    len -= len1;
    stream += len1;
    is->audio_buf_index += len1;
  }
}

static Uint32 sdl_refresh_timer_cb(Uint32 interval, void *opaque) {
  SDL_Event event;
  event.type = FF_REFRESH_EVENT;
  event.user.data1 = opaque;
  SDL_PushEvent(&event);
  return 0; /* 0 means stop timer */
}

/* schedule a video refresh in 'delay' ms */
static void schedule_refresh(VideoState *is, int delay) {
  SDL_AddTimer(delay, sdl_refresh_timer_cb, is);
}

void video_display(VideoState *is) {

  SDL_Rect rect;
  VideoPicture *vp;
  float aspect_ratio;
  int w, h, x, y;
  int i;

  vp = &is->pictq[is->pictq_rindex];
  if(vp->bmp) {

    SDL_UpdateYUVTexture( texture, NULL, 
                          vp->bmp->data[0], vp->bmp->linesize[0],
                          vp->bmp->data[1], vp->bmp->linesize[1],
                          vp->bmp->data[2], vp->bmp->linesize[2]);

    rect.x = 0;
    rect.y = 0;
    rect.w = is->video_ctx->width;
    rect.h = is->video_ctx->height;
    SDL_LockMutex(text_mutex);
    SDL_RenderClear( renderer );
    SDL_RenderCopy( renderer, texture, NULL, &rect);
    SDL_RenderPresent( renderer );
    SDL_UnlockMutex(text_mutex);

  }
}

void video_refresh_timer(void *userdata) {

  VideoState *is = (VideoState *)userdata;
  VideoPicture *vp;
  double actual_delay, delay, sync_threshold, ref_clock, diff;
  
  if(is->video_st) {
    if(is->pictq_size == 0) {
      schedule_refresh(is, 1);
      //fprintf(stderr, "no picture in the queue!!!\n");
    } else {
      //fprintf(stderr, "get picture from queue!!!\n");
      vp = &is->pictq[is->pictq_rindex];
      
      is->video_current_pts = vp->pts;
      is->video_current_pts_time = av_gettime();
      delay = vp->pts - is->frame_last_pts; /* the pts from last time */
      if(delay <= 0 || delay >= 1.0) {
  /* if incorrect delay, use previous one */
  delay = is->frame_last_delay;
      }
      /* save for next time */
      is->frame_last_delay = delay;
      is->frame_last_pts = vp->pts;

      /* update delay to sync to audio if not master source */
      if(is->av_sync_type != AV_SYNC_VIDEO_MASTER) {
  ref_clock = get_master_clock(is);
  diff = vp->pts - ref_clock;
  
  /* Skip or repeat the frame. Take delay into account
     FFPlay still doesn't "know if this is the best guess." */
  sync_threshold = (delay > AV_SYNC_THRESHOLD) ? delay : AV_SYNC_THRESHOLD;
  if(fabs(diff) < AV_NOSYNC_THRESHOLD) {
    if(diff <= -sync_threshold) {
      delay = 0;
    } else if(diff >= sync_threshold) {
      delay = 2 * delay;
    }
  }
      }
      is->frame_timer += delay;
      /* computer the REAL delay */
      actual_delay = is->frame_timer - (av_gettime() / 1000000.0);
      if(actual_delay < 0.010) {
  /* Really it should skip the picture instead */
  actual_delay = 0.010;
      }
      schedule_refresh(is, (int)(actual_delay * 1000 + 0.5));
      
      /* show the picture! */
      video_display(is);
      
      /* update queue for next picture! */
      if(++is->pictq_rindex == VIDEO_PICTURE_QUEUE_SIZE) {
  is->pictq_rindex = 0;
      }
      SDL_LockMutex(is->pictq_mutex);
      is->pictq_size--;
      SDL_CondSignal(is->pictq_cond);
      SDL_UnlockMutex(is->pictq_mutex);
    }
  } else {
    schedule_refresh(is, 100);
  }
}
      
void alloc_picture(void *userdata) {

  int ret;

  VideoState *is = (VideoState *)userdata;
  VideoPicture *vp;

  vp = &is->pictq[is->pictq_windex];
  if(vp->bmp) {

    // we already have one make another, bigger/smaller
    avpicture_free(vp->bmp);
    free(vp->bmp);

    vp->bmp = NULL;
  }

  // Allocate a place to put our YUV image on that screen
  SDL_LockMutex(text_mutex);

  vp->bmp = (AVPicture*)malloc(sizeof(AVPicture));
  ret = avpicture_alloc(vp->bmp, AV_PIX_FMT_YUV420P, is->video_ctx->width, is->video_ctx->height);
  if (ret < 0) {
      fprintf(stderr, "Could not allocate temporary picture: %s\n", av_err2str(ret));
  }

  SDL_UnlockMutex(text_mutex);

  vp->width = is->video_ctx->width;
  vp->height = is->video_ctx->height;
  vp->allocated = 1;

}

int queue_picture(VideoState *is, AVFrame *pFrame, double pts) {

  VideoPicture *vp;

  /* wait until we have space for a new pic */
  SDL_LockMutex(is->pictq_mutex);
  while(is->pictq_size >= VIDEO_PICTURE_QUEUE_SIZE &&
  !is->quit) {
    SDL_CondWait(is->pictq_cond, is->pictq_mutex);
  }
  SDL_UnlockMutex(is->pictq_mutex);

  if(is->quit)
    return -1;

  // windex is set to 0 initially
  vp = &is->pictq[is->pictq_windex];

  /* allocate or resize the buffer! */
  if(!vp->bmp ||
     vp->width != is->video_ctx->width ||
     vp->height != is->video_ctx->height) {

    vp->allocated = 0;
    alloc_picture(is);
    if(is->quit) {
      return -1;
    }
  }
  
  /* We have a place to put our picture on the queue */
  if(vp->bmp) {

    vp->pts = pts;
    
    // Convert the image into YUV format that SDL uses
    sws_scale(is->video_sws_ctx, (uint8_t const * const *)pFrame->data,
        pFrame->linesize, 0, is->video_ctx->height,
        vp->bmp->data, vp->bmp->linesize);
   
    /* now we inform our display thread that we have a pic ready */
    if(++is->pictq_windex == VIDEO_PICTURE_QUEUE_SIZE) {
      is->pictq_windex = 0;
    }

    SDL_LockMutex(is->pictq_mutex);
    is->pictq_size++;
    SDL_UnlockMutex(is->pictq_mutex);
  }
  return 0;
}

double synchronize_video(VideoState *is, AVFrame *src_frame, double pts) {

  double frame_delay;

  if(pts != 0) {
    /* if we have pts, set video clock to it */
    is->video_clock = pts;
  } else {
    /* if we aren't given a pts, set it to the clock */
    pts = is->video_clock;
  }
  /* update the video clock */
  frame_delay = av_q2d(is->video_ctx->time_base);
  /* if we are repeating a frame, adjust clock accordingly */
  frame_delay += src_frame->repeat_pict * (frame_delay * 0.5);
  is->video_clock += frame_delay;
  return pts;
}

int decode_video_thread(void *arg) {
  VideoState *is = (VideoState *)arg;
  AVPacket pkt1, *packet = &pkt1;
  int frameFinished;
  AVFrame *pFrame;
  double pts;

  pFrame = av_frame_alloc();

  for(;;) {
    if(packet_queue_get(&is->videoq, packet, 1) < 0) {
      // means we quit getting packets
      break;
    }
    pts = 0;

    // Decode video frame
    avcodec_decode_video2(is->video_ctx, pFrame, &frameFinished, packet);

    if((pts = av_frame_get_best_effort_timestamp(pFrame)) != AV_NOPTS_VALUE) {
    } else {
      pts = 0;
    }
    pts *= av_q2d(is->video_st->time_base);

    // Did we get a video frame?
    if(frameFinished) {
      pts = synchronize_video(is, pFrame, pts);
      if(queue_picture(is, pFrame, pts) < 0) {
  break;
      }
    }
    av_free_packet(packet);
  }
  av_frame_free(&pFrame);
  return 0;
}

int stream_component_open(VideoState *is, int stream_index) {

  AVFormatContext *pFormatCtx = is->pFormatCtx;
  AVCodecContext *codecCtx = NULL;
  AVCodec *codec = NULL;
  SDL_AudioSpec wanted_spec, spec;

  if(stream_index < 0 || stream_index >= pFormatCtx->nb_streams) {
    return -1;
  }

  codecCtx = avcodec_alloc_context3(NULL);


  int ret = avcodec_parameters_to_context(codecCtx, pFormatCtx->streams[stream_index]->codecpar);
  if (ret < 0)
    return -1;

  codec = avcodec_find_decoder(codecCtx->codec_id);
  if(!codec) {
    fprintf(stderr, "Unsupported codec!\n");
    return -1;
  }


  if(codecCtx->codec_type == AVMEDIA_TYPE_AUDIO) {

      // Set audio settings from codec info
      wanted_spec.freq = codecCtx->sample_rate;
      wanted_spec.format = AUDIO_S16SYS;
      wanted_spec.channels = 2;//codecCtx->channels;
      wanted_spec.silence = 0;
      wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
      wanted_spec.callback = audio_callback;
      wanted_spec.userdata = is;

      fprintf(stderr, "wanted spec: channels:%d, sample_fmt:%d, sample_rate:%d \n",
            2, AUDIO_S16SYS, codecCtx->sample_rate);

      if(SDL_OpenAudio(&wanted_spec, &spec) < 0) {
          fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError());
          return -1;
      }
      is->audio_hw_buf_size = spec.size;
  }

  if(avcodec_open2(codecCtx, codec, NULL) < 0) {
    fprintf(stderr, "Unsupported codec!\n");
    return -1;
  }

  switch(codecCtx->codec_type) {
  case AVMEDIA_TYPE_AUDIO:
    is->audioStream = stream_index;
    is->audio_st = pFormatCtx->streams[stream_index];
    is->audio_ctx = codecCtx;
    is->audio_buf_size = 0;
    is->audio_buf_index = 0;
    memset(&is->audio_pkt, 0, sizeof(is->audio_pkt));
    packet_queue_init(&is->audioq);

    //Out Audio Param
    uint64_t out_channel_layout=AV_CH_LAYOUT_STEREO;

    //AAC:1024  MP3:1152
    int out_nb_samples= is->audio_ctx->frame_size;
    //AVSampleFormat out_sample_fmt = AV_SAMPLE_FMT_S16;

    int out_sample_rate=is->audio_ctx->sample_rate;
    int out_channels=av_get_channel_layout_nb_channels(out_channel_layout);
    //Out Buffer Size
    /*
    int out_buffer_size=av_samples_get_buffer_size(NULL,
                                                   out_channels,
                                                   out_nb_samples,
                                                   AV_SAMPLE_FMT_S16,
                                                   1);
                                                   */

    //uint8_t *out_buffer=(uint8_t *)av_malloc(MAX_AUDIO_FRAME_SIZE*2);
    int64_t in_channel_layout=av_get_default_channel_layout(is->audio_ctx->channels);

    struct SwrContext *audio_convert_ctx;
    audio_convert_ctx = swr_alloc();
    swr_alloc_set_opts(audio_convert_ctx,
                       out_channel_layout,
                       AV_SAMPLE_FMT_S16,
                       out_sample_rate,
                       in_channel_layout,
                       is->audio_ctx->sample_fmt,
                       is->audio_ctx->sample_rate,
                       0,
                       NULL);
    fprintf(stderr, "swr opts: out_channel_layout:%lld, out_sample_fmt:%d, out_sample_rate:%d, in_channel_layout:%lld, in_sample_fmt:%d, in_sample_rate:%d",
            out_channel_layout, AV_SAMPLE_FMT_S16, out_sample_rate, in_channel_layout, is->audio_ctx->sample_fmt, is->audio_ctx->sample_rate);
    swr_init(audio_convert_ctx);

    is->audio_swr_ctx = audio_convert_ctx;

    SDL_PauseAudio(0);
    break;
  case AVMEDIA_TYPE_VIDEO:
    is->videoStream = stream_index;
    is->video_st = pFormatCtx->streams[stream_index];
    is->video_ctx = codecCtx;

    is->frame_timer = (double)av_gettime() / 1000000.0;
    is->frame_last_delay = 40e-3;
    is->video_current_pts_time = av_gettime();

    packet_queue_init(&is->videoq);
    is->video_sws_ctx = sws_getContext(is->video_ctx->width, is->video_ctx->height,
         is->video_ctx->pix_fmt, is->video_ctx->width,
         is->video_ctx->height, AV_PIX_FMT_YUV420P,
         SWS_BILINEAR, NULL, NULL, NULL
         );
    is->video_tid = SDL_CreateThread(decode_video_thread, "decode_video_thread", is);
    break;
  default:
    break;
  }
}

int demux_thread(void *arg) {

  int err_code;
  char errors[1024] = {0,};

  VideoState *is = (VideoState *)arg;
  AVFormatContext *pFormatCtx;
  AVPacket pkt1, *packet = &pkt1;

  int video_index = -1;
  int audio_index = -1;
  int i;

  is->videoStream=-1;
  is->audioStream=-1;

  global_video_state = is;

  /* open input file, and allocate format context */
  if ((err_code=avformat_open_input(&pFormatCtx, is->filename, NULL, NULL)) < 0) {
      av_strerror(err_code, errors, 1024);
      fprintf(stderr, "Could not open source file %s, %d(%s)\n", is->filename, err_code, errors);
      return -1;
  }

  is->pFormatCtx = pFormatCtx;
  
  // Retrieve stream information
  if(avformat_find_stream_info(pFormatCtx, NULL)<0)
    return -1; // Couldn't find stream information
  
  // Dump information about file onto standard error
  av_dump_format(pFormatCtx, 0, is->filename, 0);
  
  // Find the first video stream

  for(i=0; i<pFormatCtx->nb_streams; i++) {
    if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO &&
       video_index < 0) {
      video_index=i;
    }
    if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_AUDIO &&
       audio_index < 0) {
      audio_index=i;
    }
  }
  if(audio_index >= 0) {
    stream_component_open(is, audio_index);
  }
  if(video_index >= 0) {
    stream_component_open(is, video_index);
  }   

  if(is->videoStream < 0 || is->audioStream < 0) {
    fprintf(stderr, "%s: could not open codecs\n", is->filename);
    goto fail;
  }

  //creat window from SDL
  win = SDL_CreateWindow("Media Player",
                         SDL_WINDOWPOS_UNDEFINED,
                         SDL_WINDOWPOS_UNDEFINED,
                         is->video_ctx->width, is->video_ctx->height,
                         SDL_WINDOW_OPENGL|SDL_WINDOW_RESIZABLE);
  if(!win) {
      fprintf(stderr, "SDL: could not set video mode - exiting\n");
      exit(1);
  }

  renderer = SDL_CreateRenderer(win, -1, 0);

  //IYUV: Y + U + V  (3 planes)
  //YV12: Y + V + U  (3 planes)
  Uint32 pixformat= SDL_PIXELFORMAT_IYUV;

  //create texture for render
  texture = SDL_CreateTexture(renderer,
                              pixformat,
                              SDL_TEXTUREACCESS_STREAMING,
                              is->video_ctx->width,
                              is->video_ctx->height);


  // main decode loop

  for(;;) {
    if(is->quit) {
      break;
    }
    // seek stuff goes here
    if(is->audioq.size > MAX_AUDIOQ_SIZE ||
       is->videoq.size > MAX_VIDEOQ_SIZE) {
      SDL_Delay(10);
      continue;
    }
    if(av_read_frame(is->pFormatCtx, packet) < 0) {
      if(is->pFormatCtx->pb->error == 0) {
  SDL_Delay(100); /* no error; wait for user input */
  continue;
      } else {
  break;
      }
    }
    // Is this a packet from the video stream?
    if(packet->stream_index == is->videoStream) {
      packet_queue_put(&is->videoq, packet);
    } else if(packet->stream_index == is->audioStream) {
      packet_queue_put(&is->audioq, packet);
    } else {
      av_free_packet(packet);
    }
  }
  /* all done - wait for it */
  while(!is->quit) {
    SDL_Delay(100);
  }

 fail:
  if(1){
    SDL_Event event;
    event.type = FF_QUIT_EVENT;
    event.user.data1 = is;
    SDL_PushEvent(&event);
  }
  return 0;
}

int main(int argc, char *argv[]) {


  SDL_Event       event;

  VideoState      *is;

  is = av_mallocz(sizeof(VideoState));

  if(argc < 2) {
    fprintf(stderr, "Usage: test <file>\n");
    exit(1);
  }

  yuvfd = fopen("testout.yuv", "wb+");
  audiofd = fopen("testout.pcm", "wb+");
  // Register all formats and codecs
  av_register_all();

  if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {
    fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError());
    exit(1);
  }


  text_mutex = SDL_CreateMutex();

  av_strlcpy(is->filename, argv[1], sizeof(is->filename));

  is->pictq_mutex = SDL_CreateMutex();
  is->pictq_cond = SDL_CreateCond();

  schedule_refresh(is, 40);

  is->av_sync_type = DEFAULT_AV_SYNC_TYPE;
  is->parse_tid = SDL_CreateThread(demux_thread,"demux_thread", is);
  if(!is->parse_tid) {
    av_free(is);
    return -1;
  }
  for(;;) {

    SDL_WaitEvent(&event);
    switch(event.type) {
    case FF_QUIT_EVENT:
    case SDL_QUIT:
      is->quit = 1;
      SDL_Quit();
      return 0;
      break;
    case FF_REFRESH_EVENT:
      video_refresh_timer(event.user.data1);
      break;
    default:
      break;
    }
  }

  fclose(yuvfd);
  fclose(audiofd);
  return 0;

}