ffmpeg 0.6.3 能用的tutorial05

编译命令：
gcc -o tutorial05 tutorial05.c -lavformat -lavcodec -lz -lm -lswscale `sdl-config --cflags --libs`

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

#include <SDL.h>
#include <SDL_thread.h>

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

#define SDL_AUDIO_BUFFER_SIZE 1024
#define MAX_AUDIOQ_SIZE (5 * 6 * 1024)
#define MAX_VIDEOQ_SIZE (5 * 256 * 1024)

#define AV_SYNC_THRESHOLD 0.01
#define AV_NOSYNC_THRESHOLD 10.0

#define FF_ALLOC_EVENT (SDL_USEREVENT)
#define FF_REFRESH_EVENT (SDL_USEREVENT + 1)
#define FF_QUIT_EVENT (SDL_USEREVENT + 2)

#define VIDEO_PICTURE_QUEUE_SIZE 1


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

typedef struct VideoPicture {
  SDL_Overlay *bmp;
  int width, height;
  int allocated;
  double pts;
} VideoPicture;

typedef struct VideoState {
  AVFormatContext *pFormatCtx;
  int             videoStream, audioStream;
  double          audio_clock;
  AVStream        *audio_st;
  PacketQueue     audioq;
  uint8_t         audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2];
  unsigned int    audio_buf_size;
  unsigned int    audio_buf_index;
  AVPacket        audio_pkt;
  uint8_t         *audio_pkt_data;
  int             audio_pkt_size;
  int             audio_hw_buf_size;
  double          frame_timer;
  double          frame_last_pts;
  double          frame_last_delay;
  double          video_clock;
  AVStream        *video_st;
  PacketQueue     videoq;
  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;
  char            filename[1024];
  int             quit;
  struct SwsContext *img_convert_ctx;
} VideoState;

SDL_Surface *screen;

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;
}

static 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;
    hw_buf_size = is->audio_buf_size - is->audio_buf_index;
    bytes_per_sec = 0;
    n = is->audio_st->codec->channels * 2;
    if (is->audio_st) {
        bytes_per_sec = is->audio_st->codec->sample_rate * n;
    }
    if (bytes_per_sec) {
        pts -= (double)hw_buf_size / bytes_per_sec;
    }
    return pts;
}

int audio_decode_frame(VideoState*is, uint8_t *audio_buf, int buf_size, double *pts_ptr) {
  int len1, data_size, n;
  AVPacket *pkt = &is->audio_pkt;
  double pts;

  for (;;) {
    while (is->audio_pkt_size > 0) {
      data_size = buf_size;
      len1 = avcodec_decode_audio2(is->audio_st->codec,
                                   (int16_t *)audio_buf,
                                   &data_size,
                                   is->audio_pkt_data,
                                   is->audio_pkt_size);
      if (len1 < 0) {
            is->audio_pkt_size = 0;
            break;
      }
      is->audio_pkt_data += len1;
      is->audio_pkt_size -= len1;
      if (data_size <= 0) {
            continue;
      }
      pts = is->audio_clock;
      *pts_ptr = pts;
      n = 2 * is->audio_st->codec->channels;
      is->audio_clock += (double)data_size / (double)(n*is->audio_st->codec->sample_rate);
      return data_size;
    }
    if (pkt->data) {
      av_free_packet(pkt);
    }
    if (is->quit) {
      return -1;
    }
    if (packet_queue_get(&is->audioq, pkt, 1) < 0) {
      return -1;
    }
    is->audio_pkt_data = pkt->data;
    is->audio_pkt_size = pkt->size;
    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;

  while(len > 0) {
    if(is->audio_buf_index >= is->audio_buf_size) {
      audio_size = audio_decode_frame(is, is->audio_buf, sizeof(is->audio_buf), &pts);
      if (audio_size < 0) {
            is->audio_buf_size = 1024;
            memset(is->audio_buf, 0, is->audio_buf_size);
      } else {
            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;
    }
    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;
}

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;
  AVPicture pict;
  float aspect_ratio;
  int w, h, x, y;
  int i;

  vp = &is->pictq[is->pictq_rindex];
  if (vp->bmp) {
    if (is->video_st->codec->sample_aspect_ratio.num == 0) {
      aspect_ratio = 0;
    } else {
      aspect_ratio = av_q2d(is->video_st->codec->sample_aspect_ratio)*is->video_st->codec->width / is->video_st->codec->height;
    }
    if(aspect_ratio <= 0.0) {
      aspect_ratio = (float)is->video_st->codec->width / (float)is->video_st->codec->height;
    }
    h = screen->h;
    w = ((int)rint(h*aspect_ratio)) & -3;
    if (w > screen->w) {
      w = screen->w;
      h = ((int)rint(w / aspect_ratio)) & -3;
    }
    x = (screen->w - w) / 2;
    y = (screen->h - h) / 2;
    rect.x = x;
    rect.y = y;
    rect.w = w;
    rect.h = h;
    SDL_DisplayYUVOverlay(vp->bmp, &rect);
  }
}

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);
    } else {
      vp = &is->pictq[is->pictq_rindex];
      delay = vp->pts - is->frame_last_pts;
      if (delay <= 0 || delay >= 1.0) {
            delay = is->frame_last_delay;
      }
      is->frame_last_delay = delay;
      is->frame_last_pts = vp->pts;

      ref_clock = get_audio_clock(is);
      diff = vp->pts - ref_clock;

      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;
      actual_delay = is->frame_timer - (av_gettime() / 1000000.0);
      if (actual_delay < 0.010) {
            actual_delay = 0.010;
      }
      schedule_refresh(is, (int)(actual_delay * 1000 + 0.5));
      video_display(is);
      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) {
  VideoState *is = (VideoState *)userdata;
  VideoPicture *vp;

  vp = &is->pictq[is->pictq_windex];
  if (vp->bmp) {
    SDL_FreeYUVOverlay(vp->bmp);
  }
  vp->bmp = SDL_CreateYUVOverlay(is->video_st->codec->width,
                 is->video_st->codec->height,
                 SDL_YV12_OVERLAY,
                 screen);
  vp->width = is->video_st->codec->width;
  vp->height = is->video_st->codec->height;

  SDL_LockMutex(is->pictq_mutex);
  vp->allocated = 1;
  SDL_CondSignal(is->pictq_cond);
  SDL_UnlockMutex(is->pictq_mutex);
}

int queue_picture(VideoState *is, AVFrame *pFrame, double pts) {
  VideoPicture *vp;
  int dst_pix_fmt;
  AVPicture pict;

  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;
  }

  vp = &is->pictq[is->pictq_windex];

  if (!vp->bmp ||
      vp->width != is->video_st->codec->width ||
      vp->height != is->video_st->codec->height) {
    SDL_Event event;

    vp->allocated = 0;
    event.type = FF_ALLOC_EVENT;
    event.user.data1 = is;
    SDL_PushEvent(&event);

    SDL_LockMutex(is->pictq_mutex);
    while(!vp->allocated && !is->quit) {
      SDL_CondWait(is->pictq_cond, is->pictq_mutex);
    }
    SDL_UnlockMutex(is->pictq_mutex);
    if (is->quit) {
      return -1;
    }
  }

  if (vp->bmp) {
    SDL_LockYUVOverlay(vp->bmp);

    dst_pix_fmt = PIX_FMT_YUV420P;

    pict.data[0] = vp->bmp->pixels[0];
    pict.data[1] = vp->bmp->pixels[2];
    pict.data[2] = vp->bmp->pixels[1];

    pict.linesize[0] = vp->bmp->pitches[0];
    pict.linesize[1] = vp->bmp->pitches[2];
    pict.linesize[2] = vp->bmp->pitches[1];

    //
    sws_scale(is->img_convert_ctx,
          pFrame->data,
          pFrame->linesize, 0,
          is->video_st->codec->height,
          pict.data,
          pict.linesize);
    //

    SDL_UnlockYUVOverlay(vp->bmp);
    vp->pts = pts;

    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) {
    is->video_clock = pts;
  } else {
    pts = is->video_clock;
  }
  frame_delay = av_q2d(is->video_st->codec->time_base);
  frame_delay += src_frame->repeat_pict * (frame_delay * 0.5);
  is->video_clock += frame_delay;
  return pts;
}

uint64_t global_video_pkt_pts = AV_NOPTS_VALUE;

int our_get_buffer(struct AVCodecContext *c, AVFrame *pic) {
  int ret = avcodec_default_get_buffer(c, pic);
  uint64_t *pts = av_malloc(sizeof(uint64_t));
  *pts = global_video_pkt_pts;
  pic->opaque = pts;
  return ret;
}

void our_release_buffer(struct AVCodecContext *c, AVFrame *pic) {
  if (pic) {
    av_freep(&pic->opaque);
  }
  avcodec_default_release_buffer(c, pic);
}

int video_thread(void *arg) {
  VideoState *is = (VideoState*)arg;
  AVPacket pkt1, *packet = &pkt1;
  int len1, frameFinished;
  AVFrame *pFrame;
  double pts;

  pFrame = avcodec_alloc_frame();
  for(;;) {
    if(packet_queue_get(&is->videoq, packet, 1) < 0) {
      break;
    }
    pts = 0;
    global_video_pkt_pts = packet->pts;
    len1 = avcodec_decode_video(is->video_st->codec,
                pFrame,
                &frameFinished,
                packet->data,
                packet->size);
    if(packet->dts == AV_NOPTS_VALUE
       && pFrame->opaque
       && *(uint64_t*)pFrame->opaque
       != AV_NOPTS_VALUE) {
      pts = *(uint64_t*) pFrame->opaque;
    } else if (packet->dts != AV_NOPTS_VALUE) {
      pts = packet->dts;
    } else {
      pts = 0;
    }
    pts *= av_q2d(is->video_st->time_base);

    if (frameFinished) {
      pts = synchronize_video(is, pFrame, pts);
      if (queue_picture(is, pFrame, pts) < 0) {
    break;
      }
    }
    av_free_packet(packet);
  }
  av_free(pFrame);
  return 0;
}

int stream_component_open(VideoState *is, int stream_index) {
  AVFormatContext *pFormatCtx = is->pFormatCtx;
  AVCodecContext *codecCtx;
  AVCodec *codec;
  SDL_AudioSpec wanted_spec, spec;

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

  codecCtx = pFormatCtx->streams[stream_index]->codec;

  is->img_convert_ctx = sws_getContext(codecCtx->width,
                   codecCtx->height,
                   codecCtx->pix_fmt,
                   codecCtx->width,
                   codecCtx->height,
                   PIX_FMT_YUV420P,
                   SWS_BICUBIC,
                   NULL, NULL, NULL);

  if(codecCtx->codec_type == CODEC_TYPE_AUDIO) {
    wanted_spec.freq = codecCtx->sample_rate;
    wanted_spec.format = AUDIO_S16SYS;
    wanted_spec.channels = codecCtx->channels;
    wanted_spec.silence = 0;
    wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
    wanted_spec.callback = audio_callback;
    wanted_spec.userdata = is;

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

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

  switch(codecCtx->codec_type) {
  case CODEC_TYPE_AUDIO:
    is->audioStream = stream_index;
    is->audio_st = pFormatCtx->streams[stream_index];
    is->audio_buf_size = 0;
    is->audio_buf_index = 0;
    memset(&is->audio_pkt, 0, sizeof(is->audio_pkt));
    packet_queue_init(&is->audioq);
    SDL_PauseAudio(0);
    break;
  case CODEC_TYPE_VIDEO:
    is->videoStream = stream_index;
    is->video_st = pFormatCtx->streams[stream_index];
    is->frame_timer = (double)av_gettime() / 1000000.0;
    is->frame_last_delay = 40e-3;
    packet_queue_init(&is->videoq);
    is->video_tid = SDL_CreateThread(video_thread, is);
    codecCtx->get_buffer = our_get_buffer;
    codecCtx->release_buffer = our_release_buffer;
    break;
  default:
    break;
  }
}

int decode_interrupt_cb(void) {
  return (global_video_state && global_video_state->quit);
}

int decode_thread(void *arg) {
  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;
  url_set_interrupt_cb(decode_interrupt_cb);
  if(av_open_input_file(&pFormatCtx, is->filename, NULL, 0, NULL) != 0) {
    return -1;
  }
  is->pFormatCtx = pFormatCtx;

  if (av_find_stream_info(pFormatCtx) < 0) {
    return -1;
  }

  dump_format(pFormatCtx, 0, is->filename, 0);

  for (i=0 ; i<pFormatCtx->nb_streams; i++) {
    if (pFormatCtx->streams[i]->codec->codec_type == CODEC_TYPE_VIDEO && video_index < 0) {
      video_index = i;
    }
    if (pFormatCtx->streams[i]->codec->codec_type == CODEC_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;
  }

  for(;;) {
    if(is->quit) {
      break;
    }
    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(url_ferror(pFormatCtx->pb) == 0) {
    SDL_Delay(100);
    continue;
      } else {
    break;
      }
    }
    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);
    }
  }
  while (!is->quit) {
    SDL_Delay(100);
  }

 fail:
  {
    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 \n");
    exit(1);
  }
  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);
  }

  screen = SDL_SetVideoMode(640, 480, 24, 0);

  if(!screen) {
    fprintf(stderr, "SDL: could not set video mode - exiting\n");
    exit(1);
  }

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

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

  schedule_refresh(is, 40);

  is->parse_tid = SDL_CreateThread(decode_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();
      exit(0);
      break;
    case FF_ALLOC_EVENT:
      alloc_picture(event.user.data1);
      break;
    case FF_REFRESH_EVENT:
      video_refresh_timer(event.user.data1);
      break;
    default:
      break;
    }
  }
  return 0;
}