text: /*
   * FLV demuxer
   * Copyright (c) 2003 The FFmpeg Project
   *
   * This demuxer will generate a 1 byte extradata for VP6F content.
   * It is composed of:
   *  - upper 4 bits: difference between encoded width and visible width
   *  - lower 4 bits: difference between encoded height and visible height
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include "libavutil/avstring.h"
  #include "libavutil/channel_layout.h"
  #include "libavutil/dict.h"
  #include "libavutil/opt.h"
  #include "libavutil/internal.h"
  #include "libavutil/intfloat.h"
  #include "libavutil/mathematics.h"
  #include "libavutil/time_internal.h"
  #include "libavcodec/bytestream.h"
  #include "avformat.h"
  #include "internal.h"
  #include "avio_internal.h"
  #include "flv.h"
  
  #define VALIDATE_INDEX_TS_THRESH 2500
  
  #define RESYNC_BUFFER_SIZE (1<<20)
  
  #define MAX_DEPTH 16      ///< arbitrary limit to prevent unbounded recursion
  
  typedef struct FLVContext {
      const AVClass *class; ///< Class for private options.
      int trust_metadata;   ///< configure streams according onMetaData
      int trust_datasize;   ///< trust data size of FLVTag
      int dump_full_metadata;   ///< Dump full metadata of the onMetadata
      int wrong_dts;        ///< wrong dts due to negative cts
      uint8_t *new_extradata[FLV_STREAM_TYPE_NB];
      int new_extradata_size[FLV_STREAM_TYPE_NB];
      int last_sample_rate;
      int last_channels;
      struct {
          int64_t dts;
          int64_t pos;
      } validate_index[2];
      int validate_next;
      int validate_count;
      int searched_for_end;
  
      uint8_t resync_buffer[2*RESYNC_BUFFER_SIZE];
  
      int broken_sizes;
      int sum_flv_tag_size;
  
      int last_keyframe_stream_index;
      int keyframe_count;
      int64_t video_bit_rate;
      int64_t audio_bit_rate;
      int64_t *keyframe_times;
      int64_t *keyframe_filepositions;
      int missing_streams;
      AVRational framerate;
      int64_t last_ts;
      int64_t time_offset;
      int64_t time_pos;
  } FLVContext;
  
  /* AMF date type */
  typedef struct amf_date {
      double   milliseconds;
      int16_t  timezone;
  } amf_date;
  
  static int probe(const AVProbeData *p, int live)
  {
      const uint8_t *d = p->buf;
      unsigned offset = AV_RB32(d + 5);
  
      if (d[0] == 'F' &&
          d[1] == 'L' &&
          d[2] == 'V' &&
          d[3] < 5 && d[5] == 0 &&
          offset + 100 < p->buf_size &&
          offset > 8) {
          int is_live = !memcmp(d + offset + 40, "NGINX RTMP", 10);
  
          if (live == is_live)
              return AVPROBE_SCORE_MAX;
      }
      return 0;
  }
  
  static int flv_probe(const AVProbeData *p)
  {
      return probe(p, 0);
  }
  
  static int live_flv_probe(const AVProbeData *p)
  {
      return probe(p, 1);
  }
  
  static int kux_probe(const AVProbeData *p)
  {
      const uint8_t *d = p->buf;
  
      if (d[0] == 'K' &&
          d[1] == 'D' &&
          d[2] == 'K' &&
          d[3] == 0 &&
          d[4] == 0) {
          return AVPROBE_SCORE_EXTENSION + 1;
      }
      return 0;
  }
  
  static void add_keyframes_index(AVFormatContext *s)
  {
      FLVContext *flv   = s->priv_data;
      AVStream *stream  = NULL;
      unsigned int i    = 0;
  
      if (flv->last_keyframe_stream_index < 0) {
          av_log(s, AV_LOG_DEBUG, "keyframe stream hasn't been created\n");
          return;
      }
  
      av_assert0(flv->last_keyframe_stream_index <= s->nb_streams);
      stream = s->streams[flv->last_keyframe_stream_index];
  
      if (ffstream(stream)->nb_index_entries == 0) {
          for (i = 0; i < flv->keyframe_count; i++) {
              av_log(s, AV_LOG_TRACE, "keyframe filepositions = %"PRId64" times = %"PRId64"\n",
                     flv->keyframe_filepositions[i], flv->keyframe_times[i] * 1000);
              av_add_index_entry(stream, flv->keyframe_filepositions[i],
                  flv->keyframe_times[i] * 1000, 0, 0, AVINDEX_KEYFRAME);
          }
      } else
          av_log(s, AV_LOG_WARNING, "Skipping duplicate index\n");
  
      if (stream->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
          av_freep(&flv->keyframe_times);
          av_freep(&flv->keyframe_filepositions);
          flv->keyframe_count = 0;
      }
  }
  
  static AVStream *create_stream(AVFormatContext *s, int codec_type)
  {
      FLVContext *flv   = s->priv_data;
      AVStream *st = avformat_new_stream(s, NULL);
      if (!st)
          return NULL;
      st->codecpar->codec_type = codec_type;
      if (s->nb_streams>=3 ||(   s->nb_streams==2
                             && s->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE
                             && s->streams[1]->codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE
                             && s->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_DATA
                             && s->streams[1]->codecpar->codec_type != AVMEDIA_TYPE_DATA))
          s->ctx_flags &= ~AVFMTCTX_NOHEADER;
      if (codec_type == AVMEDIA_TYPE_AUDIO) {
          st->codecpar->bit_rate = flv->audio_bit_rate;
          flv->missing_streams &= ~FLV_HEADER_FLAG_HASAUDIO;
      }
      if (codec_type == AVMEDIA_TYPE_VIDEO) {
          st->codecpar->bit_rate = flv->video_bit_rate;
          flv->missing_streams &= ~FLV_HEADER_FLAG_HASVIDEO;
          st->avg_frame_rate = flv->framerate;
      }
  
  
      avpriv_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
      flv->last_keyframe_stream_index = s->nb_streams - 1;
      add_keyframes_index(s);
      return st;
  }
  
  static int flv_same_audio_codec(AVCodecParameters *apar, int flags)
  {
      int bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
      int flv_codecid           = flags & FLV_AUDIO_CODECID_MASK;
      int codec_id;
  
      if (!apar->codec_id && !apar->codec_tag)
          return 1;
  
      if (apar->bits_per_coded_sample != bits_per_coded_sample)
          return 0;
  
      switch (flv_codecid) {
      // no distinction between S16 and S8 PCM codec flags
      case FLV_CODECID_PCM:
          codec_id = bits_per_coded_sample == 8
                     ? AV_CODEC_ID_PCM_U8
  #if HAVE_BIGENDIAN
                     : AV_CODEC_ID_PCM_S16BE;
  #else
                     : AV_CODEC_ID_PCM_S16LE;
  #endif
          return codec_id == apar->codec_id;
      case FLV_CODECID_PCM_LE:
          codec_id = bits_per_coded_sample == 8
                     ? AV_CODEC_ID_PCM_U8
                     : AV_CODEC_ID_PCM_S16LE;
          return codec_id == apar->codec_id;
      case FLV_CODECID_AAC:
          return apar->codec_id == AV_CODEC_ID_AAC;
      case FLV_CODECID_ADPCM:
          return apar->codec_id == AV_CODEC_ID_ADPCM_SWF;
      case FLV_CODECID_SPEEX:
          return apar->codec_id == AV_CODEC_ID_SPEEX;
      case FLV_CODECID_MP3:
          return apar->codec_id == AV_CODEC_ID_MP3;
      case FLV_CODECID_NELLYMOSER_8KHZ_MONO:
      case FLV_CODECID_NELLYMOSER_16KHZ_MONO:
      case FLV_CODECID_NELLYMOSER:
          return apar->codec_id == AV_CODEC_ID_NELLYMOSER;
      case FLV_CODECID_PCM_MULAW:
          return apar->sample_rate == 8000 &&
                 apar->codec_id    == AV_CODEC_ID_PCM_MULAW;
      case FLV_CODECID_PCM_ALAW:
          return apar->sample_rate == 8000 &&
                 apar->codec_id    == AV_CODEC_ID_PCM_ALAW;
      default:
          return apar->codec_tag == (flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
      }
  }
  
  static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream,
                                  AVCodecParameters *apar, int flv_codecid)
  {
      switch (flv_codecid) {
      // no distinction between S16 and S8 PCM codec flags
      case FLV_CODECID_PCM:
          apar->codec_id = apar->bits_per_coded_sample == 8
                             ? AV_CODEC_ID_PCM_U8
  #if HAVE_BIGENDIAN
                             : AV_CODEC_ID_PCM_S16BE;
  #else
                             : AV_CODEC_ID_PCM_S16LE;
  #endif
          break;
      case FLV_CODECID_PCM_LE:
          apar->codec_id = apar->bits_per_coded_sample == 8
                             ? AV_CODEC_ID_PCM_U8
                             : AV_CODEC_ID_PCM_S16LE;
          break;
      case FLV_CODECID_AAC:
          apar->codec_id = AV_CODEC_ID_AAC;
          break;
      case FLV_CODECID_ADPCM:
          apar->codec_id = AV_CODEC_ID_ADPCM_SWF;
          break;
      case FLV_CODECID_SPEEX:
          apar->codec_id    = AV_CODEC_ID_SPEEX;
          apar->sample_rate = 16000;
          break;
      case FLV_CODECID_MP3:
          apar->codec_id      = AV_CODEC_ID_MP3;
          ffstream(astream)->need_parsing = AVSTREAM_PARSE_FULL;
          break;
      case FLV_CODECID_NELLYMOSER_8KHZ_MONO:
          // in case metadata does not otherwise declare samplerate
          apar->sample_rate = 8000;
          apar->codec_id    = AV_CODEC_ID_NELLYMOSER;
          break;
      case FLV_CODECID_NELLYMOSER_16KHZ_MONO:
          apar->sample_rate = 16000;
          apar->codec_id    = AV_CODEC_ID_NELLYMOSER;
          break;
      case FLV_CODECID_NELLYMOSER:
          apar->codec_id = AV_CODEC_ID_NELLYMOSER;
          break;
      case FLV_CODECID_PCM_MULAW:
          apar->sample_rate = 8000;
          apar->codec_id    = AV_CODEC_ID_PCM_MULAW;
          break;
      case FLV_CODECID_PCM_ALAW:
          apar->sample_rate = 8000;
          apar->codec_id    = AV_CODEC_ID_PCM_ALAW;
          break;
      default:
          avpriv_request_sample(s, "Audio codec (%x)",
                 flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
          apar->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;
      }
  }
  
  static int flv_same_video_codec(AVCodecParameters *vpar, int flags)
  {
      int flv_codecid = flags & FLV_VIDEO_CODECID_MASK;
  
      if (!vpar->codec_id && !vpar->codec_tag)
          return 1;
  
      switch (flv_codecid) {
      case FLV_CODECID_H263:
          return vpar->codec_id == AV_CODEC_ID_FLV1;
      case FLV_CODECID_SCREEN:
          return vpar->codec_id == AV_CODEC_ID_FLASHSV;
      case FLV_CODECID_SCREEN2:
          return vpar->codec_id == AV_CODEC_ID_FLASHSV2;
      case FLV_CODECID_VP6:
          return vpar->codec_id == AV_CODEC_ID_VP6F;
      case FLV_CODECID_VP6A:
          return vpar->codec_id == AV_CODEC_ID_VP6A;
      case FLV_CODECID_H264:
          return vpar->codec_id == AV_CODEC_ID_H264;
      default:
          return vpar->codec_tag == flv_codecid;
      }
  }
  
  static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream,
                                 int flv_codecid, int read)
  {
      FFStream *const vstreami = ffstream(vstream);
      int ret = 0;
      AVCodecParameters *par = vstream->codecpar;
      enum AVCodecID old_codec_id = vstream->codecpar->codec_id;
      switch (flv_codecid) {
      case FLV_CODECID_H263:
          par->codec_id = AV_CODEC_ID_FLV1;
          break;
      case FLV_CODECID_REALH263:
          par->codec_id = AV_CODEC_ID_H263;
          break; // Really mean it this time
      case FLV_CODECID_SCREEN:
          par->codec_id = AV_CODEC_ID_FLASHSV;
          break;
      case FLV_CODECID_SCREEN2:
          par->codec_id = AV_CODEC_ID_FLASHSV2;
          break;
      case FLV_CODECID_VP6:
          par->codec_id = AV_CODEC_ID_VP6F;
      case FLV_CODECID_VP6A:
          if (flv_codecid == FLV_CODECID_VP6A)
              par->codec_id = AV_CODEC_ID_VP6A;
          if (read) {
              if (par->extradata_size != 1) {
                  ff_alloc_extradata(par, 1);
              }
              if (par->extradata)
                  par->extradata[0] = avio_r8(s->pb);
              else
                  avio_skip(s->pb, 1);
          }
          ret = 1;     // 1 byte body size adjustment for flv_read_packet()
          break;
      case FLV_CODECID_H264:
          par->codec_id = AV_CODEC_ID_H264;
          vstreami->need_parsing = AVSTREAM_PARSE_HEADERS;
          ret = 3;     // not 4, reading packet type will consume one byte
          break;
      case FLV_CODECID_MPEG4:
          par->codec_id = AV_CODEC_ID_MPEG4;
          ret = 3;
          break;
      default:
          avpriv_request_sample(s, "Video codec (%x)", flv_codecid);
          par->codec_tag = flv_codecid;
      }
  
      if (!vstreami->need_context_update && par->codec_id != old_codec_id) {
          avpriv_request_sample(s, "Changing the codec id midstream");
          return AVERROR_PATCHWELCOME;
      }
  
      return ret;
  }
  
  static int amf_get_string(AVIOContext *ioc, char *buffer, int buffsize)
  {
      int ret;
      int length = avio_rb16(ioc);
      if (length >= buffsize) {
          avio_skip(ioc, length);
          return -1;
      }
  
      ret = avio_read(ioc, buffer, length);
      if (ret < 0)
          return ret;
      if (ret < length)
          return AVERROR_INVALIDDATA;
  
      buffer[length] = '\0';
  
      return length;
  }
  
  static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc, int64_t max_pos)
  {
      FLVContext *flv       = s->priv_data;
      unsigned int timeslen = 0, fileposlen = 0, i;
      char str_val[256];
      int64_t *times         = NULL;
      int64_t *filepositions = NULL;
      int ret                = AVERROR(ENOSYS);
      int64_t initial_pos    = avio_tell(ioc);
  
      if (flv->keyframe_count > 0) {
          av_log(s, AV_LOG_DEBUG, "keyframes have been parsed\n");
          return 0;
      }
      av_assert0(!flv->keyframe_times);
      av_assert0(!flv->keyframe_filepositions);
  
      if (s->flags & AVFMT_FLAG_IGNIDX)
          return 0;
  
      while (avio_tell(ioc) < max_pos - 2 &&
             amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
          int64_t **current_array;
          unsigned int arraylen;
  
          // Expect array object in context
          if (avio_r8(ioc) != AMF_DATA_TYPE_ARRAY)
              break;
  
          arraylen = avio_rb32(ioc);
          if (arraylen>>28)
              break;
  
          if       (!strcmp(KEYFRAMES_TIMESTAMP_TAG , str_val) && !times) {
              current_array = &times;
              timeslen      = arraylen;
          } else if (!strcmp(KEYFRAMES_BYTEOFFSET_TAG, str_val) &&
                     !filepositions) {
              current_array = &filepositions;
              fileposlen    = arraylen;
          } else
              // unexpected metatag inside keyframes, will not use such
              // metadata for indexing
              break;
  
          if (!(*current_array = av_mallocz(sizeof(**current_array) * arraylen))) {
              ret = AVERROR(ENOMEM);
              goto finish;
          }
  
          for (i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++) {
              double d;
              if (avio_r8(ioc) != AMF_DATA_TYPE_NUMBER)
                  goto invalid;
              d = av_int2double(avio_rb64(ioc));
              if (isnan(d) || d < INT64_MIN || d > INT64_MAX)
                  goto invalid;
              current_array[0][i] = d;
          }
          if (times && filepositions) {
              // All done, exiting at a position allowing amf_parse_object
              // to finish parsing the object
              ret = 0;
              break;
          }
      }
  
      if (timeslen == fileposlen && fileposlen>1 && max_pos <= filepositions[0]) {
          for (i = 0; i < FFMIN(2,fileposlen); i++) {
              flv->validate_index[i].pos = filepositions[i];
              flv->validate_index[i].dts = times[i] * 1000;
              flv->validate_count        = i + 1;
          }
          flv->keyframe_times = times;
          flv->keyframe_filepositions = filepositions;
          flv->keyframe_count = timeslen;
          times = NULL;
          filepositions = NULL;
      } else {
  invalid:
          av_log(s, AV_LOG_WARNING, "Invalid keyframes object, skipping.\n");
      }
  
  finish:
      av_freep(&times);
      av_freep(&filepositions);
      avio_seek(ioc, initial_pos, SEEK_SET);
      return ret;
  }
  
  static int amf_parse_object(AVFormatContext *s, AVStream *astream,
                              AVStream *vstream, const char *key,
                              int64_t max_pos, int depth)
  {
      AVCodecParameters *apar, *vpar;
      FLVContext *flv = s->priv_data;
      AVIOContext *ioc;
      AMFDataType amf_type;
      char str_val[1024];
      double num_val;
      amf_date date;
  
      if (depth > MAX_DEPTH)
          return AVERROR_PATCHWELCOME;
  
      num_val  = 0;
      ioc      = s->pb;
      if (avio_feof(ioc))
          return AVERROR_EOF;
      amf_type = avio_r8(ioc);
  
      switch (amf_type) {
      case AMF_DATA_TYPE_NUMBER:
          num_val = av_int2double(avio_rb64(ioc));
          break;
      case AMF_DATA_TYPE_BOOL:
          num_val = avio_r8(ioc);
          break;
      case AMF_DATA_TYPE_STRING:
          if (amf_get_string(ioc, str_val, sizeof(str_val)) < 0) {
              av_log(s, AV_LOG_ERROR, "AMF_DATA_TYPE_STRING parsing failed\n");
              return -1;
          }
          break;
      case AMF_DATA_TYPE_OBJECT:
          if (key &&
              (ioc->seekable & AVIO_SEEKABLE_NORMAL) &&
              !strcmp(KEYFRAMES_TAG, key) && depth == 1)
              if (parse_keyframes_index(s, ioc, max_pos) < 0)
                  av_log(s, AV_LOG_ERROR, "Keyframe index parsing failed\n");
              else
                  add_keyframes_index(s);
          while (avio_tell(ioc) < max_pos - 2 &&
                 amf_get_string(ioc, str_val, sizeof(str_val)) > 0)
              if (amf_parse_object(s, astream, vstream, str_val, max_pos,
                                   depth + 1) < 0)
                  return -1;     // if we couldn't skip, bomb out.
          if (avio_r8(ioc) != AMF_END_OF_OBJECT) {
              av_log(s, AV_LOG_ERROR, "Missing AMF_END_OF_OBJECT in AMF_DATA_TYPE_OBJECT\n");
              return -1;
          }
          break;
      case AMF_DATA_TYPE_NULL:
      case AMF_DATA_TYPE_UNDEFINED:
      case AMF_DATA_TYPE_UNSUPPORTED:
          break;     // these take up no additional space
      case AMF_DATA_TYPE_MIXEDARRAY:
      {
          unsigned v;
          avio_skip(ioc, 4);     // skip 32-bit max array index
          while (avio_tell(ioc) < max_pos - 2 &&
                 amf_get_string(ioc, str_val, sizeof(str_val)) > 0)
              // this is the only case in which we would want a nested
              // parse to not skip over the object
              if (amf_parse_object(s, astream, vstream, str_val, max_pos,
                                   depth + 1) < 0)
                  return -1;
          v = avio_r8(ioc);
          if (v != AMF_END_OF_OBJECT) {
              av_log(s, AV_LOG_ERROR, "Missing AMF_END_OF_OBJECT in AMF_DATA_TYPE_MIXEDARRAY, found %d\n", v);
              return -1;
          }
          break;
      }
      case AMF_DATA_TYPE_ARRAY:
      {
          unsigned int arraylen, i;
  
          arraylen = avio_rb32(ioc);
          for (i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++)
              if (amf_parse_object(s, NULL, NULL, NULL, max_pos,
                                   depth + 1) < 0)
                  return -1;      // if we couldn't skip, bomb out.
      }
      break;
      case AMF_DATA_TYPE_DATE:
          // timestamp (double) and UTC offset (int16)
          date.milliseconds = av_int2double(avio_rb64(ioc));
          date.timezone = avio_rb16(ioc);
          break;
      default:                    // unsupported type, we couldn't skip
          av_log(s, AV_LOG_ERROR, "unsupported amf type %d\n", amf_type);
          return -1;
      }
  
      if (key) {
          apar = astream ? astream->codecpar : NULL;
          vpar = vstream ? vstream->codecpar : NULL;
  
          // stream info doesn't live any deeper than the first object
          if (depth == 1) {
              if (amf_type == AMF_DATA_TYPE_NUMBER ||
                  amf_type == AMF_DATA_TYPE_BOOL) {
                  if (!strcmp(key, "duration"))
                      s->duration = num_val * AV_TIME_BASE;
                  else if (!strcmp(key, "videodatarate") &&
                           0 <= (int)(num_val * 1024.0))
                      flv->video_bit_rate = num_val * 1024.0;
                  else if (!strcmp(key, "audiodatarate") &&
                           0 <= (int)(num_val * 1024.0))
                      flv->audio_bit_rate = num_val * 1024.0;
                  else if (!strcmp(key, "datastream")) {
                      AVStream *st = create_stream(s, AVMEDIA_TYPE_SUBTITLE);
                      if (!st)
                          return AVERROR(ENOMEM);
                      st->codecpar->codec_id = AV_CODEC_ID_TEXT;
                  } else if (!strcmp(key, "framerate")) {
                      flv->framerate = av_d2q(num_val, 1000);
                      if (vstream)
                          vstream->avg_frame_rate = flv->framerate;
                  } else if (flv->trust_metadata) {
                      if (!strcmp(key, "videocodecid") && vpar) {
                          int ret = flv_set_video_codec(s, vstream, num_val, 0);
                          if (ret < 0)
                              return ret;
                      } else if (!strcmp(key, "audiocodecid") && apar) {
                          int id = ((int)num_val) << FLV_AUDIO_CODECID_OFFSET;
                          flv_set_audio_codec(s, astream, apar, id);
                      } else if (!strcmp(key, "audiosamplerate") && apar) {
                          apar->sample_rate = num_val;
                      } else if (!strcmp(key, "audiosamplesize") && apar) {
                          apar->bits_per_coded_sample = num_val;
                      } else if (!strcmp(key, "stereo") && apar) {
                          apar->channels       = num_val + 1;
                          apar->channel_layout = apar->channels == 2 ?
                                                 AV_CH_LAYOUT_STEREO :
                                                 AV_CH_LAYOUT_MONO;
                      } else if (!strcmp(key, "width") && vpar) {
                          vpar->width = num_val;
                      } else if (!strcmp(key, "height") && vpar) {
                          vpar->height = num_val;
                      }
                  }
              }
              if (amf_type == AMF_DATA_TYPE_STRING) {
                  if (!strcmp(key, "encoder")) {
                      int version = -1;
                      if (1 == sscanf(str_val, "Open Broadcaster Software v0.%d", &version)) {
                          if (version > 0 && version <= 655)
                              flv->broken_sizes = 1;
                      }
                  } else if (!strcmp(key, "metadatacreator")) {
                      if (   !strcmp (str_val, "MEGA")
                          || !strncmp(str_val, "FlixEngine", 10))
                          flv->broken_sizes = 1;
                  }
              }
          }
  
          if (amf_type == AMF_DATA_TYPE_OBJECT && s->nb_streams == 1 &&
             ((!apar && !strcmp(key, "audiocodecid")) ||
              (!vpar && !strcmp(key, "videocodecid"))))
                  s->ctx_flags &= ~AVFMTCTX_NOHEADER; //If there is either audio/video missing, codecid will be an empty object
  
          if ((!strcmp(key, "duration")        ||
              !strcmp(key, "filesize")        ||
              !strcmp(key, "width")           ||
              !strcmp(key, "height")          ||
              !strcmp(key, "videodatarate")   ||
              !strcmp(key, "framerate")       ||
              !strcmp(key, "videocodecid")    ||
              !strcmp(key, "audiodatarate")   ||
              !strcmp(key, "audiosamplerate") ||
              !strcmp(key, "audiosamplesize") ||
              !strcmp(key, "stereo")          ||
              !strcmp(key, "audiocodecid")    ||
              !strcmp(key, "datastream")) && !flv->dump_full_metadata)
              return 0;
  
          s->event_flags |= AVFMT_EVENT_FLAG_METADATA_UPDATED;
          if (amf_type == AMF_DATA_TYPE_BOOL) {
              av_strlcpy(str_val, num_val > 0 ? "true" : "false",
                         sizeof(str_val));
              av_dict_set(&s->metadata, key, str_val, 0);
          } else if (amf_type == AMF_DATA_TYPE_NUMBER) {
              snprintf(str_val, sizeof(str_val), "%.f", num_val);
              av_dict_set(&s->metadata, key, str_val, 0);
          } else if (amf_type == AMF_DATA_TYPE_STRING) {
              av_dict_set(&s->metadata, key, str_val, 0);
          } else if (   amf_type == AMF_DATA_TYPE_DATE
                     && isfinite(date.milliseconds)
                     && date.milliseconds > INT64_MIN/1000
                     && date.milliseconds < INT64_MAX/1000
                    ) {
              // timezone is ignored, since there is no easy way to offset the UTC
              // timestamp into the specified timezone
              avpriv_dict_set_timestamp(&s->metadata, key, 1000 * (int64_t)date.milliseconds);
          }
      }
  
      return 0;
  }
  
  #define TYPE_ONTEXTDATA 1
  #define TYPE_ONCAPTION 2
  #define TYPE_ONCAPTIONINFO 3
  #define TYPE_UNKNOWN 9
  
  static int flv_read_metabody(AVFormatContext *s, int64_t next_pos)
  {
      FLVContext *flv = s->priv_data;
      AMFDataType type;
      AVStream *stream, *astream, *vstream;
      AVStream av_unused *dstream;
      AVIOContext *ioc;
      int i;
      char buffer[32];
  
      astream = NULL;
      vstream = NULL;
      dstream = NULL;
      ioc     = s->pb;
  
      // first object needs to be "onMetaData" string
      type = avio_r8(ioc);
      if (type != AMF_DATA_TYPE_STRING ||
          amf_get_string(ioc, buffer, sizeof(buffer)) < 0)
          return TYPE_UNKNOWN;
  
      if (!strcmp(buffer, "onTextData"))
          return TYPE_ONTEXTDATA;
  
      if (!strcmp(buffer, "onCaption"))
          return TYPE_ONCAPTION;
  
      if (!strcmp(buffer, "onCaptionInfo"))
          return TYPE_ONCAPTIONINFO;
  
      if (strcmp(buffer, "onMetaData") && strcmp(buffer, "onCuePoint") && strcmp(buffer, "|RtmpSampleAccess")) {
          av_log(s, AV_LOG_DEBUG, "Unknown type %s\n", buffer);
          return TYPE_UNKNOWN;
      }
  
      // find the streams now so that amf_parse_object doesn't need to do
      // the lookup every time it is called.
      for (i = 0; i < s->nb_streams; i++) {
          stream = s->streams[i];
          if (stream->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
              vstream = stream;
              flv->last_keyframe_stream_index = i;
          } else if (stream->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
              astream = stream;
              if (flv->last_keyframe_stream_index == -1)
                  flv->last_keyframe_stream_index = i;
          } else if (stream->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE)
              dstream = stream;
      }
  
      // parse the second object (we want a mixed array)
      if (amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)
          return -1;
  
      return 0;
  }
  
  static int flv_read_header(AVFormatContext *s)
  {
      int flags;
      FLVContext *flv = s->priv_data;
      int offset;
      int pre_tag_size = 0;
  
      /* Actual FLV data at 0xe40000 in KUX file */
      if(!strcmp(s->iformat->name, "kux"))
          avio_skip(s->pb, 0xe40000);
  
      avio_skip(s->pb, 4);
      flags = avio_r8(s->pb);
  
      flv->missing_streams = flags & (FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO);
  
      s->ctx_flags |= AVFMTCTX_NOHEADER;
  
      offset = avio_rb32(s->pb);
      avio_seek(s->pb, offset, SEEK_SET);
  
      /* Annex E. The FLV File Format
       * E.3 TheFLVFileBody
       *     Field               Type    Comment
       *     PreviousTagSize0    UI32    Always 0
       * */
      pre_tag_size = avio_rb32(s->pb);
      if (pre_tag_size) {
          av_log(s, AV_LOG_WARNING, "Read FLV header error, input file is not a standard flv format, first PreviousTagSize0 always is 0\n");
      }
  
      s->start_time = 0;
      flv->sum_flv_tag_size = 0;
      flv->last_keyframe_stream_index = -1;
  
      return 0;
  }
  
  static int flv_read_close(AVFormatContext *s)
  {
      int i;
      FLVContext *flv = s->priv_data;
      for (i=0; i<FLV_STREAM_TYPE_NB; i++)
          av_freep(&flv->new_extradata[i]);
      av_freep(&flv->keyframe_times);
      av_freep(&flv->keyframe_filepositions);
      return 0;
  }
  
  static int flv_get_extradata(AVFormatContext *s, AVStream *st, int size)
  {
      int ret;
      if (!size)
          return 0;
  
      if ((ret = ff_get_extradata(s, st->codecpar, s->pb, size)) < 0)
          return ret;
      ffstream(st)->need_context_update = 1;
      return 0;
  }
  
  static int flv_queue_extradata(FLVContext *flv, AVIOContext *pb, int stream,
                                 int size)
  {
      if (!size)
          return 0;
  
      av_free(flv->new_extradata[stream]);
      flv->new_extradata[stream] = av_mallocz(size +
                                              AV_INPUT_BUFFER_PADDING_SIZE);
      if (!flv->new_extradata[stream])
          return AVERROR(ENOMEM);
      flv->new_extradata_size[stream] = size;
      avio_read(pb, flv->new_extradata[stream], size);
      return 0;
  }
  
  static void clear_index_entries(AVFormatContext *s, int64_t pos)
  {
      av_log(s, AV_LOG_WARNING,
             "Found invalid index entries, clearing the index.\n");
      for (unsigned i = 0; i < s->nb_streams; i++) {
          FFStream *const sti = ffstream(s->streams[i]);
          int out = 0;
          /* Remove all index entries that point to >= pos */
          for (int j = 0; j < sti->nb_index_entries; j++)
              if (sti->index_entries[j].pos < pos)
                  sti->index_entries[out++] = sti->index_entries[j];
          sti->nb_index_entries = out;
      }
  }
  
  static int amf_skip_tag(AVIOContext *pb, AMFDataType type, int depth)
  {
      int nb = -1, ret, parse_name = 1;
  
      if (depth > MAX_DEPTH)
          return AVERROR_PATCHWELCOME;
  
      if (avio_feof(pb))
          return AVERROR_EOF;
  
      switch (type) {
      case AMF_DATA_TYPE_NUMBER:
          avio_skip(pb, 8);
          break;
      case AMF_DATA_TYPE_BOOL:
          avio_skip(pb, 1);
          break;
      case AMF_DATA_TYPE_STRING:
          avio_skip(pb, avio_rb16(pb));
          break;
      case AMF_DATA_TYPE_ARRAY:
          parse_name = 0;
      case AMF_DATA_TYPE_MIXEDARRAY:
          nb = avio_rb32(pb);
          if (nb < 0)
              return AVERROR_INVALIDDATA;
      case AMF_DATA_TYPE_OBJECT:
          while(!pb->eof_reached && (nb-- > 0 || type != AMF_DATA_TYPE_ARRAY)) {
              if (parse_name) {
                  int size = avio_rb16(pb);
                  if (!size) {
                      avio_skip(pb, 1);
                      break;
                  }
                  avio_skip(pb, size);
              }
              if ((ret = amf_skip_tag(pb, avio_r8(pb), depth + 1)) < 0)
                  return ret;
          }
          break;
      case AMF_DATA_TYPE_NULL:
      case AMF_DATA_TYPE_OBJECT_END:
          break;
      default:
          return AVERROR_INVALIDDATA;
      }
      return 0;
  }
  
  static int flv_data_packet(AVFormatContext *s, AVPacket *pkt,
                             int64_t dts, int64_t next)
  {
      AVIOContext *pb = s->pb;
      AVStream *st    = NULL;
      char buf[20];
      int ret = AVERROR_INVALIDDATA;
      int i, length = -1;
      int array = 0;
  
      switch (avio_r8(pb)) {
      case AMF_DATA_TYPE_ARRAY:
          array = 1;
      case AMF_DATA_TYPE_MIXEDARRAY:
          avio_seek(pb, 4, SEEK_CUR);
      case AMF_DATA_TYPE_OBJECT:
          break;
      default:
          goto skip;
      }
  
      while (array || (ret = amf_get_string(pb, buf, sizeof(buf))) > 0) {
          AMFDataType type = avio_r8(pb);
          if (type == AMF_DATA_TYPE_STRING && (array || !strcmp(buf, "text"))) {
              length = avio_rb16(pb);
              ret    = av_get_packet(pb, pkt, length);
              if (ret < 0)
                  goto skip;
              else
                  break;
          } else {
              if ((ret = amf_skip_tag(pb, type, 0)) < 0)
                  goto skip;
          }
      }
  
      if (length < 0) {
          ret = AVERROR_INVALIDDATA;
          goto skip;
      }
  
      for (i = 0; i < s->nb_streams; i++) {
          st = s->streams[i];
          if (st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE)
              break;
      }
  
      if (i == s->nb_streams) {
          st = create_stream(s, AVMEDIA_TYPE_SUBTITLE);
          if (!st)
              return AVERROR(ENOMEM);
          st->codecpar->codec_id = AV_CODEC_ID_TEXT;
      }
  
      pkt->dts  = dts;
      pkt->pts  = dts;
      pkt->size = ret;
  
      pkt->stream_index = st->index;
      pkt->flags       |= AV_PKT_FLAG_KEY;
  
  skip:
      avio_seek(s->pb, next + 4, SEEK_SET);
  
      return ret;
  }
  
  static int resync(AVFormatContext *s)
  {
      FLVContext *flv = s->priv_data;
      int64_t i;
      int64_t pos = avio_tell(s->pb);
  
      for (i=0; !avio_feof(s->pb); i++) {
          int j  = i & (RESYNC_BUFFER_SIZE-1);
          int j1 = j + RESYNC_BUFFER_SIZE;
          flv->resync_buffer[j ] =
          flv->resync_buffer[j1] = avio_r8(s->pb);
  
          if (i >= 8 && pos) {
              uint8_t *d = flv->resync_buffer + j1 - 8;
              if (d[0] == 'F' &&
                  d[1] == 'L' &&
                  d[2] == 'V' &&
                  d[3] < 5 && d[5] == 0) {
                  av_log(s, AV_LOG_WARNING, "Concatenated FLV detected, might fail to demux, decode and seek %"PRId64"\n", flv->last_ts);
                  flv->time_offset = flv->last_ts + 1;
                  flv->time_pos    = avio_tell(s->pb);
              }
          }
  
          if (i > 22) {
              unsigned lsize2 = AV_RB32(flv->resync_buffer + j1 - 4);
              if (lsize2 >= 11 && lsize2 + 8LL < FFMIN(i, RESYNC_BUFFER_SIZE)) {
                  unsigned  size2 = AV_RB24(flv->resync_buffer + j1 - lsize2 + 1 - 4);
                  unsigned lsize1 = AV_RB32(flv->resync_buffer + j1 - lsize2 - 8);
                  if (lsize1 >= 11 && lsize1 + 8LL + lsize2 < FFMIN(i, RESYNC_BUFFER_SIZE)) {
                      unsigned  size1 = AV_RB24(flv->resync_buffer + j1 - lsize1 + 1 - lsize2 - 8);
                      if (size1 == lsize1 - 11 && size2  == lsize2 - 11) {
                          avio_seek(s->pb, pos + i - lsize1 - lsize2 - 8, SEEK_SET);
                          return 1;
                      }
                  }
              }
          }
      }
      return AVERROR_EOF;
  }
  
  static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
  {
      FLVContext *flv = s->priv_data;
      int ret, i, size, flags;
      enum FlvTagType type;
      int stream_type=-1;
      int64_t next, pos, meta_pos;
      int64_t dts, pts = AV_NOPTS_VALUE;
      int av_uninit(channels);
      int av_uninit(sample_rate);
      AVStream *st    = NULL;
      int last = -1;
      int orig_size;
  
  retry:
      /* pkt size is repeated at end. skip it */
      pos  = avio_tell(s->pb);
      type = (avio_r8(s->pb) & 0x1F);
      orig_size =
      size = avio_rb24(s->pb);
      flv->sum_flv_tag_size += size + 11;
      dts  = avio_rb24(s->pb);
      dts |= (unsigned)avio_r8(s->pb) << 24;
      av_log(s, AV_LOG_TRACE, "type:%d, size:%d, last:%d, dts:%"PRId64" pos:%"PRId64"\n", type, size, last, dts, avio_tell(s->pb));
      if (avio_feof(s->pb))
          return AVERROR_EOF;
      avio_skip(s->pb, 3); /* stream id, always 0 */
      flags = 0;
  
      if (flv->validate_next < flv->validate_count) {
          int64_t validate_pos = flv->validate_index[flv->validate_next].pos;
          if (pos == validate_pos) {
              if (FFABS(dts - flv->validate_index[flv->validate_next].dts) <=
                  VALIDATE_INDEX_TS_THRESH) {
                  flv->validate_next++;
              } else {
                  clear_index_entries(s, validate_pos);
                  flv->validate_count = 0;
              }
          } else if (pos > validate_pos) {
              clear_index_entries(s, validate_pos);
              flv->validate_count = 0;
          }
      }
  
      if (size == 0) {
          ret = FFERROR_REDO;
          goto leave;
      }
  
      next = size + avio_tell(s->pb);
  
      if (type == FLV_TAG_TYPE_AUDIO) {
          stream_type = FLV_STREAM_TYPE_AUDIO;
          flags    = avio_r8(s->pb);
          size--;
      } else if (type == FLV_TAG_TYPE_VIDEO) {
          stream_type = FLV_STREAM_TYPE_VIDEO;
          flags    = avio_r8(s->pb);
          size--;
          if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_VIDEO_INFO_CMD)
              goto skip;
      } else if (type == FLV_TAG_TYPE_META) {
          stream_type=FLV_STREAM_TYPE_SUBTITLE;
          if (size > 13 + 1 + 4) { // Header-type metadata stuff
              int type;
              meta_pos = avio_tell(s->pb);
              type = flv_read_metabody(s, next);
              if (type == 0 && dts == 0 || type < 0) {
                  if (type < 0 && flv->validate_count &&
                      flv->validate_index[0].pos     > next &&
                      flv->validate_index[0].pos - 4 < next) {
                      av_log(s, AV_LOG_WARNING, "Adjusting next position due to index mismatch\n");
                      next = flv->validate_index[0].pos - 4;
                  }
                  goto skip;
              } else if (type == TYPE_ONTEXTDATA) {
                  avpriv_request_sample(s, "OnTextData packet");
                  return flv_data_packet(s, pkt, dts, next);
              } else if (type == TYPE_ONCAPTION) {
                  return flv_data_packet(s, pkt, dts, next);
              } else if (type == TYPE_UNKNOWN) {
                  stream_type = FLV_STREAM_TYPE_DATA;
              }
              avio_seek(s->pb, meta_pos, SEEK_SET);
          }
      } else {
          av_log(s, AV_LOG_DEBUG,
                 "Skipping flv packet: type %d, size %d, flags %d.\n",
                 type, size, flags);
  skip:
          if (avio_seek(s->pb, next, SEEK_SET) != next) {
              // This can happen if flv_read_metabody above read past
              // next, on a non-seekable input, and the preceding data has
              // been flushed out from the IO buffer.
              av_log(s, AV_LOG_ERROR, "Unable to seek to the next packet\n");
              return AVERROR_INVALIDDATA;
          }
          ret = FFERROR_REDO;
          goto leave;
      }
  
      /* skip empty data packets */
      if (!size) {
          ret = FFERROR_REDO;
          goto leave;
      }
  
      /* now find stream */
      for (i = 0; i < s->nb_streams; i++) {
          st = s->streams[i];
          if (stream_type == FLV_STREAM_TYPE_AUDIO) {
              if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
                  (s->audio_codec_id || flv_same_audio_codec(st->codecpar, flags)))
                  break;
          } else if (stream_type == FLV_STREAM_TYPE_VIDEO) {
              if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
                  (s->video_codec_id || flv_same_video_codec(st->codecpar, flags)))
                  break;
          } else if (stream_type == FLV_STREAM_TYPE_SUBTITLE) {
              if (st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE)
                  break;
          } else if (stream_type == FLV_STREAM_TYPE_DATA) {
              if (st->codecpar->codec_type == AVMEDIA_TYPE_DATA)
                  break;
          }
      }
      if (i == s->nb_streams) {
          static const enum AVMediaType stream_types[] = {AVMEDIA_TYPE_VIDEO, AVMEDIA_TYPE_AUDIO, AVMEDIA_TYPE_SUBTITLE, AVMEDIA_TYPE_DATA};
          st = create_stream(s, stream_types[stream_type]);
          if (!st)
              return AVERROR(ENOMEM);
      }
      av_log(s, AV_LOG_TRACE, "%d %X %d \n", stream_type, flags, st->discard);
  
      if (flv->time_pos <= pos) {
          dts += flv->time_offset;
      }
  
      if ((s->pb->seekable & AVIO_SEEKABLE_NORMAL) &&
          ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY ||
           stream_type == FLV_STREAM_TYPE_AUDIO))
          av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);
  
      if ((st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY || stream_type == FLV_STREAM_TYPE_AUDIO)) ||
          (st->discard >= AVDISCARD_BIDIR && ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && stream_type == FLV_STREAM_TYPE_VIDEO)) ||
           st->discard >= AVDISCARD_ALL) {
          avio_seek(s->pb, next, SEEK_SET);
          ret = FFERROR_REDO;
          goto leave;
      }
  
      // if not streamed and no duration from metadata then seek to end to find
      // the duration from the timestamps
      if ((s->pb->seekable & AVIO_SEEKABLE_NORMAL) &&
          (!s->duration || s->duration == AV_NOPTS_VALUE) &&
          !flv->searched_for_end) {
          int size;
          const int64_t pos   = avio_tell(s->pb);
          // Read the last 4 bytes of the file, this should be the size of the
          // previous FLV tag. Use the timestamp of its payload as duration.
          int64_t fsize       = avio_size(s->pb);
  retry_duration:
          avio_seek(s->pb, fsize - 4, SEEK_SET);
          size = avio_rb32(s->pb);
          if (size > 0 && size < fsize) {
              // Seek to the start of the last FLV tag at position (fsize - 4 - size)
              // but skip the byte indicating the type.
              avio_seek(s->pb, fsize - 3 - size, SEEK_SET);
              if (size == avio_rb24(s->pb) + 11) {
                  uint32_t ts = avio_rb24(s->pb);
                  ts         |= (unsigned)avio_r8(s->pb) << 24;
                  if (ts)
                      s->duration = ts * (int64_t)AV_TIME_BASE / 1000;
                  else if (fsize >= 8 && fsize - 8 >= size) {
                      fsize -= size+4;
                      goto retry_duration;
                  }
              }
          }
  
          avio_seek(s->pb, pos, SEEK_SET);
          flv->searched_for_end = 1;
      }
  
      if (stream_type == FLV_STREAM_TYPE_AUDIO) {
          int bits_per_coded_sample;
          channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
          sample_rate = 44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >>
                                  FLV_AUDIO_SAMPLERATE_OFFSET) >> 3;
          bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
          if (!st->codecpar->channels || !st->codecpar->sample_rate ||
              !st->codecpar->bits_per_coded_sample) {
              st->codecpar->channels              = channels;
              st->codecpar->channel_layout        = channels == 1
                                                 ? AV_CH_LAYOUT_MONO
                                                 : AV_CH_LAYOUT_STEREO;
              st->codecpar->sample_rate           = sample_rate;
              st->codecpar->bits_per_coded_sample = bits_per_coded_sample;
          }
          if (!st->codecpar->codec_id) {
              flv_set_audio_codec(s, st, st->codecpar,
                                  flags & FLV_AUDIO_CODECID_MASK);
              flv->last_sample_rate =
              sample_rate           = st->codecpar->sample_rate;
              flv->last_channels    =
              channels              = st->codecpar->channels;
          } else {
              AVCodecParameters *par = avcodec_parameters_alloc();
              if (!par) {
                  ret = AVERROR(ENOMEM);
                  goto leave;
              }
              par->sample_rate = sample_rate;
              par->bits_per_coded_sample = bits_per_coded_sample;
              flv_set_audio_codec(s, st, par, flags & FLV_AUDIO_CODECID_MASK);
              sample_rate = par->sample_rate;
              avcodec_parameters_free(&par);
          }
      } else if (stream_type == FLV_STREAM_TYPE_VIDEO) {
          int ret = flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK, 1);
          if (ret < 0)
              return ret;
          size -= ret;
      } else if (stream_type == FLV_STREAM_TYPE_SUBTITLE) {
          st->codecpar->codec_id = AV_CODEC_ID_TEXT;
      } else if (stream_type == FLV_STREAM_TYPE_DATA) {
          st->codecpar->codec_id = AV_CODEC_ID_NONE; // Opaque AMF data
      }
  
      if (st->codecpar->codec_id == AV_CODEC_ID_AAC ||
          st->codecpar->codec_id == AV_CODEC_ID_H264 ||
          st->codecpar->codec_id == AV_CODEC_ID_MPEG4) {
          int type = avio_r8(s->pb);
          size--;
  
          if (size < 0) {
              ret = AVERROR_INVALIDDATA;
              goto leave;
          }
  
          if (st->codecpar->codec_id == AV_CODEC_ID_H264 || st->codecpar->codec_id == AV_CODEC_ID_MPEG4) {
              // sign extension
              int32_t cts = (avio_rb24(s->pb) + 0xff800000) ^ 0xff800000;
              pts = av_sat_add64(dts, cts);
              if (cts < 0) { // dts might be wrong
                  if (!flv->wrong_dts)
                      av_log(s, AV_LOG_WARNING,
                          "Negative cts, previous timestamps might be wrong.\n");
                  flv->wrong_dts = 1;
              } else if (FFABS(dts - pts) > 1000*60*15) {
                  av_log(s, AV_LOG_WARNING,
                         "invalid timestamps %"PRId64" %"PRId64"\n", dts, pts);
                  dts = pts = AV_NOPTS_VALUE;
              }
          }
          if (type == 0 && (!st->codecpar->extradata || st->codecpar->codec_id == AV_CODEC_ID_AAC ||
              st->codecpar->codec_id == AV_CODEC_ID_H264)) {
              AVDictionaryEntry *t;
  
              if (st->codecpar->extradata) {
                  if ((ret = flv_queue_extradata(flv, s->pb, stream_type, size)) < 0)
                      return ret;
                  ret = FFERROR_REDO;
                  goto leave;
              }
              if ((ret = flv_get_extradata(s, st, size)) < 0)
                  return ret;
  
              /* Workaround for buggy Omnia A/XE encoder */
              t = av_dict_get(s->metadata, "Encoder", NULL, 0);
              if (st->codecpar->codec_id == AV_CODEC_ID_AAC && t && !strcmp(t->value, "Omnia A/XE"))
                  st->codecpar->extradata_size = 2;
  
              ret = FFERROR_REDO;
              goto leave;
          }
      }
  
      /* skip empty data packets */
      if (!size) {
          ret = FFERROR_REDO;
          goto leave;
      }
  
      ret = av_get_packet(s->pb, pkt, size);
      if (ret < 0)
          return ret;
      pkt->dts          = dts;
      pkt->pts          = pts == AV_NOPTS_VALUE ? dts : pts;
      pkt->stream_index = st->index;
      pkt->pos          = pos;
      if (flv->new_extradata[stream_type]) {
          int ret = av_packet_add_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA,
                                            flv->new_extradata[stream_type],
                                            flv->new_extradata_size[stream_type]);
          if (ret >= 0) {
              flv->new_extradata[stream_type]      = NULL;
              flv->new_extradata_size[stream_type] = 0;
          }
      }
      if (stream_type == FLV_STREAM_TYPE_AUDIO &&
                      (sample_rate != flv->last_sample_rate ||
                       channels    != flv->last_channels)) {
          flv->last_sample_rate = sample_rate;
          flv->last_channels    = channels;
          ff_add_param_change(pkt, channels, 0, sample_rate, 0, 0);
      }
  
      if (stream_type == FLV_STREAM_TYPE_AUDIO ||
          (flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY ||
          stream_type == FLV_STREAM_TYPE_SUBTITLE ||
          stream_type == FLV_STREAM_TYPE_DATA)
          pkt->flags |= AV_PKT_FLAG_KEY;
  
  leave:
      last = avio_rb32(s->pb);
      if (!flv->trust_datasize) {
          if (last != orig_size + 11 && last != orig_size + 10 &&
              !avio_feof(s->pb) &&
              (last != orig_size || !last) && last != flv->sum_flv_tag_size &&
              !flv->broken_sizes) {
              av_log(s, AV_LOG_ERROR, "Packet mismatch %d %d %d\n", last, orig_size + 11, flv->sum_flv_tag_size);
              avio_seek(s->pb, pos + 1, SEEK_SET);
              ret = resync(s);
              av_packet_unref(pkt);
              if (ret >= 0) {
                  goto retry;
              }
          }
      }
  
      if (ret >= 0)
          flv->last_ts = pkt->dts;
  
      return ret;
  }
  
  static int flv_read_seek(AVFormatContext *s, int stream_index,
                           int64_t ts, int flags)
  {
      FLVContext *flv = s->priv_data;
      flv->validate_count = 0;
      return avio_seek_time(s->pb, stream_index, ts, flags);
  }
  
  #define OFFSET(x) offsetof(FLVContext, x)
  #define VD AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM
  static const AVOption options[] = {
      { "flv_metadata", "Allocate streams according to the onMetaData array", OFFSET(trust_metadata), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, VD },
      { "flv_full_metadata", "Dump full metadata of the onMetadata", OFFSET(dump_full_metadata), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, VD },
      { "flv_ignore_prevtag", "Ignore the Size of previous tag", OFFSET(trust_datasize), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, VD },
      { "missing_streams", "", OFFSET(missing_streams), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 0xFF, VD | AV_OPT_FLAG_EXPORT | AV_OPT_FLAG_READONLY },
      { NULL }
  };
  
  static const AVClass flv_kux_class = {
      .class_name = "(live) flv/kux demuxer",
      .item_name  = av_default_item_name,
      .option     = options,
      .version    = LIBAVUTIL_VERSION_INT,
  };
  
  const AVInputFormat ff_flv_demuxer = {
      .name           = "flv",
      .long_name      = NULL_IF_CONFIG_SMALL("FLV (Flash Video)"),
      .priv_data_size = sizeof(FLVContext),
      .read_probe     = flv_probe,
      .read_header    = flv_read_header,
      .read_packet    = flv_read_packet,
      .read_seek      = flv_read_seek,
      .read_close     = flv_read_close,
      .extensions     = "flv",
      .priv_class     = &flv_kux_class,
  };
  
  const AVInputFormat ff_live_flv_demuxer = {
      .name           = "live_flv",
      .long_name      = NULL_IF_CONFIG_SMALL("live RTMP FLV (Flash Video)"),
      .priv_data_size = sizeof(FLVContext),
      .read_probe     = live_flv_probe,
      .read_header    = flv_read_header,
      .read_packet    = flv_read_packet,
      .read_seek      = flv_read_seek,
      .read_close     = flv_read_close,
      .extensions     = "flv",
      .priv_class     = &flv_kux_class,
      .flags          = AVFMT_TS_DISCONT
  };
  
  const AVInputFormat ff_kux_demuxer = {
      .name           = "kux",
      .long_name      = NULL_IF_CONFIG_SMALL("KUX (YouKu)"),
      .priv_data_size = sizeof(FLVContext),
      .read_probe     = kux_probe,
      .read_header    = flv_read_header,
      .read_packet    = flv_read_packet,
      .read_seek      = flv_read_seek,
      .read_close     = flv_read_close,
      .extensions     = "kux",
      .priv_class     = &flv_kux_class,
  };
  