ffmpeg tutorial 05 with SDL2 and audio resampling fix

ffmpeg_tutorial05.c

// tutorial05.c
// A pedagogical video player that really works!
//
// 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
// With updates from https://github.com/chelyaev/ffmpeg-tutorial
// Updates tested on:
// LAVC 54.59.100, LAVF 54.29.104, LSWS 2.1.101, SDL 1.2.15
// on GCC 4.7.2 in Debian February 2015
// Use
//
//gcc -g -o tutorial05 ffmpeg_tutorial05.c -lavformat -lavcodec -lswscale -lavutil -lswresample -lz -ldl `sdl2-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
// tutorial04 myvideofile.mpg
//
// to play the video stream on your screen.

#include <libavutil/opt.h>
#include <libavutil/samplefmt.h>
#include <libavcodec/avcodec.h>
#include <libavutil/avstring.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libswresample/swresample.h>

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

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

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

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

#define VIDEO_PICTURE_QUEUE_SIZE 1
#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audio

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; */
  SDL_Texture *texture;
  Uint8 *yPlane, *uPlane, *vPlane;
  size_t yPlaneSz, uvPlaneSz;
  int uvPitch;
  int width, height; /* source height & width */
  int allocated;
  double pts;
} VideoPicture;

typedef struct VideoState {

  AVFormatContext *pFormatCtx;
  int             videoStream, audioStream;

  double          audio_clock;
  AVStream        *audio_st;
  AVCodecContext  *audio_ctx;
  PacketQueue     audioq;
  uint8_t         audio_buf[(AVCODEC_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;
  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
  AVStream        *video_st;
  AVCodecContext  *video_ctx;
  PacketQueue     videoq;
  struct SwsContext *sws_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;

  char            filename[1024];
  int             quit;
} VideoState;

SDL_Window *screen = NULL;
SDL_mutex       *screen_mutex;
SDL_Renderer *renderer = 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;
}
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_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;
}

static int audio_resampling(AVCodecContext *audio_decode_ctx,
                            AVFrame *audio_decode_frame,
                            enum AVSampleFormat out_sample_fmt,
                            int out_channels,
                            int out_sample_rate,
                            uint8_t *out_buf)
{
    SwrContext *swr_ctx = NULL;
    int ret = 0;
    int64_t in_channel_layout = audio_decode_ctx->channel_layout;
    int64_t out_channel_layout = AV_CH_LAYOUT_STEREO;
    int out_nb_channels = 0;
    int out_linesize = 0;
    int in_nb_samples = 0;
    int out_nb_samples = 0;
    int max_out_nb_samples = 0;
    uint8_t **resampled_data = NULL;
    int resampled_data_size = 0;

    swr_ctx = swr_alloc();
    if (!swr_ctx) {
        printf("swr_alloc error\n");
        return -1;
    }

    in_channel_layout = (audio_decode_ctx->channels ==
                     av_get_channel_layout_nb_channels(audio_decode_ctx->channel_layout)) ?
                     audio_decode_ctx->channel_layout :
                     av_get_default_channel_layout(audio_decode_ctx->channels);
    if (in_channel_layout <=0) {
        printf("in_channel_layout error\n");
        return -1;
    }

    if (out_channels == 1) {
        out_channel_layout = AV_CH_LAYOUT_MONO;
    } else if (out_channels == 2) {
        out_channel_layout = AV_CH_LAYOUT_STEREO;
    } else {
        out_channel_layout = AV_CH_LAYOUT_SURROUND;
    }

    in_nb_samples = audio_decode_frame->nb_samples;
    if (in_nb_samples <=0) {
        printf("in_nb_samples error\n");
        return -1;
    }

    av_opt_set_int(swr_ctx, "in_channel_layout", in_channel_layout, 0);
    av_opt_set_int(swr_ctx, "in_sample_rate", audio_decode_ctx->sample_rate, 0);
    av_opt_set_sample_fmt(swr_ctx, "in_sample_fmt", audio_decode_ctx->sample_fmt, 0);

    av_opt_set_int(swr_ctx, "out_channel_layout", out_channel_layout, 0);
    av_opt_set_int(swr_ctx, "out_sample_rate", out_sample_rate, 0);
    av_opt_set_sample_fmt(swr_ctx, "out_sample_fmt", out_sample_fmt, 0);

    if ((ret = swr_init(swr_ctx)) < 0) {
        printf("Failed to initialize the resampling context\n");
        return -1;
    }

    max_out_nb_samples = out_nb_samples = av_rescale_rnd(in_nb_samples,
                                                         out_sample_rate,
                                                         audio_decode_ctx->sample_rate,
                                                         AV_ROUND_UP);

    if (max_out_nb_samples <= 0) {
        printf("av_rescale_rnd error\n");
        return -1;
    }

    out_nb_channels = av_get_channel_layout_nb_channels(out_channel_layout);

    ret = av_samples_alloc_array_and_samples(&resampled_data, &out_linesize, out_nb_channels, out_nb_samples, out_sample_fmt, 0);
    if (ret < 0) {
        printf("av_samples_alloc_array_and_samples error\n");
        return -1;
    }

    out_nb_samples = av_rescale_rnd(swr_get_delay(swr_ctx, audio_decode_ctx->sample_rate) + in_nb_samples,
                                    out_sample_rate, audio_decode_ctx->sample_rate, AV_ROUND_UP);
    if (out_nb_samples <= 0) {
        printf("av_rescale_rnd error\n");
        return -1;
    }

    if (out_nb_samples > max_out_nb_samples) {
        av_free(resampled_data[0]);
        ret = av_samples_alloc(resampled_data, &out_linesize, out_nb_channels, out_nb_samples, out_sample_fmt, 1);
        max_out_nb_samples = out_nb_samples;
    }

    if (swr_ctx) {
        ret = swr_convert(swr_ctx, resampled_data, out_nb_samples,
                          (const uint8_t **)audio_decode_frame->data, audio_decode_frame->nb_samples);
        if (ret < 0) {
            printf("swr_convert_error\n");
            return -1;
        }

        resampled_data_size = av_samples_get_buffer_size(&out_linesize, out_nb_channels, ret, out_sample_fmt, 1);
        if (resampled_data_size < 0) {
            printf("av_samples_get_buffer_size error\n");
            return -1;
        }
    } else {
        printf("swr_ctx null error\n");
        return -1;
    }

    memcpy(out_buf, resampled_data[0], resampled_data_size);

    if (resampled_data) {
        av_freep(&resampled_data[0]);
    }
    av_freep(&resampled_data);
    resampled_data = NULL;

    if (swr_ctx) {
        swr_free(&swr_ctx);
    }
    return resampled_data_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 = audio_resampling(is->audio_ctx, &is->audio_frame, AV_SAMPLE_FMT_S16, is->audio_frame.channels, is->audio_frame.sample_rate, audio_buf);
            assert(data_size <= buf_size);
	/* data_size = av_samples_get_buffer_size(NULL,  */
						   /* is->audio_ctx->channels, */
						   /* is->audio_frame.nb_samples, */
						   /* is->audio_ctx->sample_fmt, */
						   /* 1); */
	/* assert(data_size <= buf_size); */
	/* 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;

  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 {
	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;
  float aspect_ratio;
  int w, h, x, y;
  int i;

  vp = &is->pictq[is->pictq_rindex];
  if(vp->texture) {
    if(is->video_ctx->sample_aspect_ratio.num == 0) {
      aspect_ratio = 0;
    } else {
      aspect_ratio = av_q2d(is->video_ctx->sample_aspect_ratio) *
	is->video_ctx->width / is->video_ctx->height;
    }
    if(aspect_ratio <= 0.0) {
      aspect_ratio = (float)is->video_ctx->width /
	(float)is->video_ctx->height;
    }
    SDL_LockMutex(screen_mutex);
                SDL_UpdateYUVTexture(
                        vp->texture,
                        NULL,
                        vp->yPlane,
                        is->video_ctx->width,
                        vp->uPlane,
                        vp->uvPitch,
                        vp->vPlane,
                        vp->uvPitch
                    );
                SDL_RenderClear(renderer);
                SDL_RenderCopy(renderer, vp->texture, NULL, NULL);
                SDL_RenderPresent(renderer);
    SDL_UnlockMutex(screen_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);
    } else {
      vp = &is->pictq[is->pictq_rindex];

      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 */
      ref_clock = get_audio_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) {

  VideoState *is = (VideoState *)userdata;
  VideoPicture *vp;
  float aspect_ratio;
  int w, h, x, y;
  int scr_w, scr_h;
  int i;

  vp = &is->pictq[is->pictq_windex];
  if(vp->texture) {
    // we already have one make another, bigger/smaller
    SDL_DestroyTexture(vp->texture);
  }
  // Allocate a place to put our YUV image on that screen
  SDL_LockMutex(screen_mutex);
    if(is->video_ctx->sample_aspect_ratio.num == 0) {
      aspect_ratio = 0;
    } else {
      aspect_ratio = av_q2d(is->video_ctx->sample_aspect_ratio) *
	is->video_ctx->width / is->video_ctx->height;
    }
    if(aspect_ratio <= 0.0) {
      aspect_ratio = (float)is->video_ctx->width /
	(float)is->video_ctx->height;
    }
    SDL_GetWindowSize(screen, &scr_w, &scr_h);
    h = scr_h;
    w = ((int)rint(h * aspect_ratio)) & -3;
    if(w > scr_w) {
      w = scr_w;
      h = ((int)rint(w / aspect_ratio)) & -3;
    }
    x = (scr_w - w) / 2;
    y = (scr_h - h) / 2;
    printf("screen final size: %dx%d\n", w, h);

    vp->texture = SDL_CreateTexture(
            renderer,
            SDL_PIXELFORMAT_YV12,
            SDL_TEXTUREACCESS_STREAMING,
            /* is->video_ctx->width, */
            w,
            /* is->video_ctx->height */
            h
        );
    vp->yPlaneSz = w * h;
    /* vp->yPlaneSz = is->video_ctx->width * is->video_ctx->height; */
    vp->uvPlaneSz = w * h / 4;
    /* vp->uvPlaneSz = is->video_ctx->width * is->video_ctx->height / 4; */
    vp->yPlane = (Uint8*)malloc(vp->yPlaneSz);
    vp->uPlane = (Uint8*)malloc(vp->uvPlaneSz);
    vp->vPlane = (Uint8*)malloc(vp->uvPlaneSz);
    if (!vp->yPlane || !vp->uPlane || !vp->vPlane) {
        fprintf(stderr, "Could not allocate pixel buffers - exiting\n");
        exit(1);
    }

    vp->uvPitch = is->video_ctx->width / 2;

  SDL_UnlockMutex(screen_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;
  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 buffer! */
  if(!vp->texture||
     vp->width != is->video_ctx->width ||
     vp->height != is->video_ctx->height) {
    SDL_Event event;

    vp->allocated = 0;
    alloc_picture(is);
    if(is->quit) {
      return -1;
    }
  }

  /* We have a place to put our picture on the queue */

  if(vp->texture) {

    vp->pts = pts;

    dst_pix_fmt = AV_PIX_FMT_YUV420P;
    /* point pict at the queue */


    pict.data[0] = vp->yPlane;
    pict.data[1] = vp->uPlane;
    pict.data[2] = vp->vPlane;

    pict.linesize[0] = vp->width;
    pict.linesize[1] = vp->uvPitch;
    pict.linesize[2] = vp->uvPitch;

    // Convert the image into YUV format that SDL uses
    sws_scale(is->sws_ctx, (uint8_t const * const *)pFrame->data,
	      pFrame->linesize, 0, is->video_ctx->height,
	      pict.data, pict.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 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;
    }
    /* 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) {
      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;
  }

  codec = avcodec_find_decoder(pFormatCtx->streams[stream_index]->codec->codec_id);
  if(!codec) {
    fprintf(stderr, "Unsupported codec!\n");
    return -1;
  }

  codecCtx = avcodec_alloc_context3(codec);
  if(avcodec_copy_context(codecCtx, pFormatCtx->streams[stream_index]->codec) != 0) {
    fprintf(stderr, "Couldn't copy codec context");
    return -1; // Error copying codec context
  }

  if (codecCtx->codec_type == AVMEDIA_TYPE_VIDEO) {
      SDL_SetWindowSize(screen, codecCtx->width, codecCtx->height);
  }

  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 = 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;
  }
  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);
    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;

    packet_queue_init(&is->videoq);
    is->video_tid = SDL_CreateThread(video_thread, "video_thread", is);
    is->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
				 );
    break;
  default:
    break;
  }
}

int decode_thread(void *arg) {

  VideoState *is = (VideoState *)arg;
  AVFormatContext *pFormatCtx = NULL;
  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 video file
  if(avformat_open_input(&pFormatCtx, is->filename, NULL, NULL)!=0)
    return -1; // Couldn't open file

  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;
  }

  // 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);
  }
  // Register all formats and codecs
  av_register_all();
  // init network
  avformat_network_init();

  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 */
    screen = SDL_CreateWindow(
            "FFmpeg Tutorial",
            SDL_WINDOWPOS_UNDEFINED,
            SDL_WINDOWPOS_UNDEFINED,
            /* 1280, */
            /* 640, */
            1280,
            /* pCodecCtx->width, */
            /* 800, */
            /* 480, */
            800,
            /* pCodecCtx->height, */
            0
        );
  if(!screen) {
    fprintf(stderr, "SDL: could not set video mode - exiting\n");
    exit(1);
  }

    renderer = SDL_CreateRenderer(screen, -1, 0);
    if (!renderer) {
        fprintf(stderr, "SDL: could not create renderer - exiting\n");
        exit(1);
    }
  screen_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->parse_tid = SDL_CreateThread(decode_thread, "video_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;
    }
  }
  return 0;

}