ffmpeg 0.6.3 能用的tutorial06

编译命令：
gcc -o tutorial04 tutorial04.c -lavformat -lavcodec -lz -lm -lswscale `sdl-config --cflags --libs`

点击(此处)折叠或打开

 // tutorial06.c
 // A pedagogical video player that really
 //
 // Code based on FFplay, Copyright (c) 2003 Fabrice Bellard,
 // and a tutorial by Martin Bohme (boehme@inb.uni-luebeckREMOVETHIS.de)
 // Tested on Gentoo, CVS version 5/01/07 compiled with GCC 4.1.1
 // Use
 //
 // gcc -o tutorial02 tutorial02.c -lavformat -lavcodec -lz -lm `sdl-config --cflags --libs`
 // to build (assuming libavformat and libavcodec are correctly installed,
 // and assuming you have sdl-config. Please refer to SDL docs for your installation.)
 //
 // Run using
 // tutorial06 myvideofile.mpg
 //
 // to play the video.

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

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

 #ifdef __MINGW32__
 #undef main /* Prevents SDL from overriding main() */
 #endif

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

 #define SDL_AUDIO_BUFFER_SIZE 1024

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

 #define VIDEO_PICTURE_QUEUE_SIZE 1

 #define DEFAULT_AV_SYNC_TYPE 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 {
   SDL_Overlay *bmp;
   int width, height; /* source height & width */
   int allocated;
   double pts;
 } VideoPicture;

 typedef struct VideoState {

   AVFormatContext *pFormatCtx;
   int videoStream, audioStream;

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

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

 enum {
   AV_SYNC_AUDIO_MASTER,
   AV_SYNC_VIDEO_MASTER,
   AV_SYNC_EXTERNAL_MASTER,
 };

 SDL_Surface *screen;

 /* 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;
 }
 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; /* maintained in the audio thread */
   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;
 }
 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_st->codec->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_st->codec->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, 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) {
     /* if error, skip frame */
     is->audio_pkt_size = 0;
     break;
       }
       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_st->codec->channels;
       is->audio_clock += (double)data_size /
     (double)(n * is->audio_st->codec->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;

   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;
     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;
     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;
   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];

       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 */
       video_display(is);

       /* update queue for next */
       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) {
     // we already have one make another, bigger/smaller
     SDL_FreeYUVOverlay(vp->bmp);
   }
   // Allocate a place to put our YUV image on that screen
   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;

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

     vp->allocated = 0;
     /* we have to do it in the main thread */
     event.type = FF_ALLOC_EVENT;
     event.user.data1 = is;
     SDL_PushEvent(&event);

     /* wait until we have a picture allocated */
     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;
     }
   }
   /* We have a place to put our picture on the queue */
   /* If we are skipping a frame, do we set this to null
      but still return vp->allocated = 1? */


   if(vp->bmp) {

     SDL_LockYUVOverlay(vp->bmp);

     dst_pix_fmt = PIX_FMT_YUV420P;
     /* point pict at the queue */

     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];

     // Convert the image into YUV format that SDL uses
     /*
     img_convert(&pict, dst_pix_fmt,
         (AVPicture *)pFrame, is->video_st->codec->pix_fmt,
         is->video_st->codec->width, is->video_st->codec->height);
     */
     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;

     /* 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_st->codec->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;
 }

 uint64_t global_video_pkt_pts = AV_NOPTS_VALUE;

 /* These are called whenever we allocate a frame
  * buffer. We use this to store the global_pts in
  * a frame at the time it is allocated.
  */
 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) {
       // means we quit getting packets
       break;
     }
     pts = 0;

     // Save global pts to be stored in pFrame in first call
     global_video_pkt_pts = packet->pts;
     // Decode video frame
     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);

     // 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_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;
   }

   // Get a pointer to the codec context for the video stream
   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) {
     // Set audio settings from codec info
     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;

     /* averaging filter for audio sync */
     is->audio_diff_avg_coef = exp(log(0.01 / AUDIO_DIFF_AVG_NB));
     is->audio_diff_avg_count = 0;
     /* Correct audio only if larger error than this */
     is->audio_diff_threshold = 2.0 * SDL_AUDIO_BUFFER_SIZE / codecCtx->sample_rate;

     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;
     is->video_current_pts_time = av_gettime();

     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;
   // will interrupt blocking functions if we
   url_set_interrupt_cb(decode_interrupt_cb);

   // Open video file
   if(av_open_input_file(&pFormatCtx, is->filename, NULL, 0, NULL)!=0)
     return -1; // Couldn't open file

   is->pFormatCtx = pFormatCtx;

   // Retrieve stream information
   if(av_find_stream_info(pFormatCtx)<0)
     return -1; // Couldn't find stream information

   // Dump information about file onto standard error
   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==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;
   }

   // 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(url_ferror(&pFormatCtx->pb) == 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:
   {
     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);
   }
   // 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);
   }

   // Make a screen to put our video
 #ifndef __DARWIN__
         screen = SDL_SetVideoMode(640, 480, 0, 0);
 #else
         screen = SDL_SetVideoMode(640, 480, 24, 0);
 #endif
   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->av_sync_type = DEFAULT_AV_SYNC_TYPE;
   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;

 }