text: /*
   * "Real" compatible demuxer.
   * Copyright (c) 2000, 2001 Fabrice Bellard
   *
   * 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 <inttypes.h>
  
  #include "libavutil/avassert.h"
  #include "libavutil/avstring.h"
  #include "libavutil/channel_layout.h"
  #include "libavutil/internal.h"
  #include "libavutil/intreadwrite.h"
  #include "libavutil/dict.h"
  #include "avformat.h"
  #include "avio_internal.h"
  #include "internal.h"
  #include "rmsipr.h"
  #include "rm.h"
  
  #define DEINT_ID_GENR MKTAG('g', 'e', 'n', 'r') ///< interleaving for Cooker/ATRAC
  #define DEINT_ID_INT0 MKTAG('I', 'n', 't', '0') ///< no interleaving needed
  #define DEINT_ID_INT4 MKTAG('I', 'n', 't', '4') ///< interleaving for 28.8
  #define DEINT_ID_SIPR MKTAG('s', 'i', 'p', 'r') ///< interleaving for Sipro
  #define DEINT_ID_VBRF MKTAG('v', 'b', 'r', 'f') ///< VBR case for AAC
  #define DEINT_ID_VBRS MKTAG('v', 'b', 'r', 's') ///< VBR case for AAC
  
  struct RMStream {
      AVPacket pkt;      ///< place to store merged video frame / reordered audio data
      int videobufsize;  ///< current assembled frame size
      int videobufpos;   ///< position for the next slice in the video buffer
      int curpic_num;    ///< picture number of current frame
      int cur_slice, slices;
      int64_t pktpos;    ///< first slice position in file
      /// Audio descrambling matrix parameters
      int64_t audiotimestamp; ///< Audio packet timestamp
      int sub_packet_cnt; // Subpacket counter, used while reading
      int sub_packet_size, sub_packet_h, coded_framesize; ///< Descrambling parameters from container
      int audio_framesize; /// Audio frame size from container
      int sub_packet_lengths[16]; /// Length of each subpacket
      int32_t deint_id;  ///< deinterleaver used in audio stream
  };
  
  typedef struct RMDemuxContext {
      int nb_packets;
      int old_format;
      int current_stream;
      int remaining_len;
      int audio_stream_num; ///< Stream number for audio packets
      int audio_pkt_cnt; ///< Output packet counter
      int data_end;
  } RMDemuxContext;
  
  static int rm_read_close(AVFormatContext *s);
  
  static inline void get_strl(AVIOContext *pb, char *buf, int buf_size, int len)
  {
      int i;
      char *q, r;
  
      q = buf;
      for(i=0;i<len;i++) {
          r = avio_r8(pb);
          if (i < buf_size - 1)
              *q++ = r;
      }
      if (buf_size > 0) *q = '\0';
  }
  
  static void get_str8(AVIOContext *pb, char *buf, int buf_size)
  {
      get_strl(pb, buf, buf_size, avio_r8(pb));
  }
  
  static int rm_read_extradata(AVFormatContext *s, AVIOContext *pb, AVCodecParameters *par, unsigned size)
  {
      if (size >= 1<<24) {
          av_log(s, AV_LOG_ERROR, "extradata size %u too large\n", size);
          return -1;
      }
      if (ff_get_extradata(s, par, pb, size) < 0)
          return AVERROR(ENOMEM);
      return 0;
  }
  
  static void rm_read_metadata(AVFormatContext *s, AVIOContext *pb, int wide)
  {
      char buf[1024];
      int i;
  
      for (i=0; i<FF_ARRAY_ELEMS(ff_rm_metadata); i++) {
          int len = wide ? avio_rb16(pb) : avio_r8(pb);
          get_strl(pb, buf, sizeof(buf), len);
          av_dict_set(&s->metadata, ff_rm_metadata[i], buf, 0);
      }
  }
  
  RMStream *ff_rm_alloc_rmstream (void)
  {
      RMStream *rms = av_mallocz(sizeof(RMStream));
      if (!rms)
          return NULL;
      rms->curpic_num = -1;
      return rms;
  }
  
  void ff_rm_free_rmstream (RMStream *rms)
  {
      av_packet_unref(&rms->pkt);
  }
  
  static int rm_read_audio_stream_info(AVFormatContext *s, AVIOContext *pb,
                                       AVStream *st, RMStream *ast, int read_all)
  {
      char buf[256];
      uint32_t version;
      int ret;
  
      /* ra type header */
      version = avio_rb16(pb); /* version */
      if (version == 3) {
          unsigned bytes_per_minute;
          int header_size = avio_rb16(pb);
          int64_t startpos = avio_tell(pb);
          avio_skip(pb, 8);
          bytes_per_minute = avio_rb16(pb);
          avio_skip(pb, 4);
          rm_read_metadata(s, pb, 0);
          if ((startpos + header_size) >= avio_tell(pb) + 2) {
              // fourcc (should always be "lpcJ")
              avio_r8(pb);
              get_str8(pb, buf, sizeof(buf));
          }
          // Skip extra header crap (this should never happen)
          if ((startpos + header_size) > avio_tell(pb))
              avio_skip(pb, header_size + startpos - avio_tell(pb));
          if (bytes_per_minute)
              st->codecpar->bit_rate = 8LL * bytes_per_minute / 60;
          st->codecpar->sample_rate = 8000;
          st->codecpar->channels = 1;
          st->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
          st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
          st->codecpar->codec_id = AV_CODEC_ID_RA_144;
          ast->deint_id = DEINT_ID_INT0;
      } else {
          int flavor, sub_packet_h, coded_framesize, sub_packet_size;
          int codecdata_length;
          unsigned bytes_per_minute;
          /* old version (4) */
          avio_skip(pb, 2); /* unused */
          avio_rb32(pb); /* .ra4 */
          avio_rb32(pb); /* data size */
          avio_rb16(pb); /* version2 */
          avio_rb32(pb); /* header size */
          flavor= avio_rb16(pb); /* add codec info / flavor */
          ast->coded_framesize = coded_framesize = avio_rb32(pb); /* coded frame size */
          avio_rb32(pb); /* ??? */
          bytes_per_minute = avio_rb32(pb);
          if (version == 4) {
              if (bytes_per_minute)
                  st->codecpar->bit_rate = 8LL * bytes_per_minute / 60;
          }
          avio_rb32(pb); /* ??? */
          ast->sub_packet_h = sub_packet_h = avio_rb16(pb); /* 1 */
          st->codecpar->block_align= avio_rb16(pb); /* frame size */
          ast->sub_packet_size = sub_packet_size = avio_rb16(pb); /* sub packet size */
          avio_rb16(pb); /* ??? */
          if (version == 5) {
              avio_rb16(pb); avio_rb16(pb); avio_rb16(pb);
          }
          st->codecpar->sample_rate = avio_rb16(pb);
          avio_rb32(pb);
          st->codecpar->channels = avio_rb16(pb);
          if (version == 5) {
              ast->deint_id = avio_rl32(pb);
              avio_read(pb, buf, 4);
              buf[4] = 0;
          } else {
              AV_WL32(buf, 0);
              get_str8(pb, buf, sizeof(buf)); /* desc */
              ast->deint_id = AV_RL32(buf);
              get_str8(pb, buf, sizeof(buf)); /* desc */
          }
          st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
          st->codecpar->codec_tag  = AV_RL32(buf);
          st->codecpar->codec_id   = ff_codec_get_id(ff_rm_codec_tags,
                                                     st->codecpar->codec_tag);
  
          switch (st->codecpar->codec_id) {
          case AV_CODEC_ID_AC3:
              st->need_parsing = AVSTREAM_PARSE_FULL;
              break;
          case AV_CODEC_ID_RA_288:
              st->codecpar->extradata_size= 0;
              av_freep(&st->codecpar->extradata);
              ast->audio_framesize = st->codecpar->block_align;
              st->codecpar->block_align = coded_framesize;
              break;
          case AV_CODEC_ID_COOK:
              st->need_parsing = AVSTREAM_PARSE_HEADERS;
          case AV_CODEC_ID_ATRAC3:
          case AV_CODEC_ID_SIPR:
              if (read_all) {
                  codecdata_length = 0;
              } else {
                  avio_rb16(pb); avio_r8(pb);
                  if (version == 5)
                      avio_r8(pb);
                  codecdata_length = avio_rb32(pb);
                  if(codecdata_length + AV_INPUT_BUFFER_PADDING_SIZE <= (unsigned)codecdata_length){
                      av_log(s, AV_LOG_ERROR, "codecdata_length too large\n");
                      return -1;
                  }
              }
  
              ast->audio_framesize = st->codecpar->block_align;
              if (st->codecpar->codec_id == AV_CODEC_ID_SIPR) {
                  if (flavor > 3) {
                      av_log(s, AV_LOG_ERROR, "bad SIPR file flavor %d\n",
                             flavor);
                      return -1;
                  }
                  st->codecpar->block_align = ff_sipr_subpk_size[flavor];
              } else {
                  if(sub_packet_size <= 0){
                      av_log(s, AV_LOG_ERROR, "sub_packet_size is invalid\n");
                      return -1;
                  }
                  st->codecpar->block_align = ast->sub_packet_size;
              }
              if ((ret = rm_read_extradata(s, pb, st->codecpar, codecdata_length)) < 0)
                  return ret;
  
              break;
          case AV_CODEC_ID_AAC:
              avio_rb16(pb); avio_r8(pb);
              if (version == 5)
                  avio_r8(pb);
              codecdata_length = avio_rb32(pb);
              if(codecdata_length + AV_INPUT_BUFFER_PADDING_SIZE <= (unsigned)codecdata_length){
                  av_log(s, AV_LOG_ERROR, "codecdata_length too large\n");
                  return -1;
              }
              if (codecdata_length >= 1) {
                  avio_r8(pb);
                  if ((ret = rm_read_extradata(s, pb, st->codecpar, codecdata_length - 1)) < 0)
                      return ret;
              }
              break;
          }
          switch (ast->deint_id) {
          case DEINT_ID_INT4:
              if (ast->coded_framesize > ast->audio_framesize ||
                  sub_packet_h <= 1 ||
                  ast->coded_framesize * sub_packet_h > (2 + (sub_packet_h & 1)) * ast->audio_framesize)
                  return AVERROR_INVALIDDATA;
              if (ast->coded_framesize * sub_packet_h != 2*ast->audio_framesize) {
                  avpriv_request_sample(s, "mismatching interleaver parameters");
                  return AVERROR_INVALIDDATA;
              }
              break;
          case DEINT_ID_GENR:
              if (ast->sub_packet_size <= 0 ||
                  ast->sub_packet_size > ast->audio_framesize)
                  return AVERROR_INVALIDDATA;
              if (ast->audio_framesize % ast->sub_packet_size)
                  return AVERROR_INVALIDDATA;
              break;
          case DEINT_ID_SIPR:
          case DEINT_ID_INT0:
          case DEINT_ID_VBRS:
          case DEINT_ID_VBRF:
              break;
          default:
              av_log(s, AV_LOG_ERROR ,"Unknown interleaver %"PRIX32"\n", ast->deint_id);
              return AVERROR_INVALIDDATA;
          }
          if (ast->deint_id == DEINT_ID_INT4 ||
              ast->deint_id == DEINT_ID_GENR ||
              ast->deint_id == DEINT_ID_SIPR) {
              if (st->codecpar->block_align <= 0 ||
                  ast->audio_framesize * sub_packet_h > (unsigned)INT_MAX ||
                  ast->audio_framesize * sub_packet_h < st->codecpar->block_align)
                  return AVERROR_INVALIDDATA;
              if (av_new_packet(&ast->pkt, ast->audio_framesize * sub_packet_h) < 0)
                  return AVERROR(ENOMEM);
          }
  
          if (read_all) {
              avio_r8(pb);
              avio_r8(pb);
              avio_r8(pb);
              rm_read_metadata(s, pb, 0);
          }
      }
      return 0;
  }
  
  int ff_rm_read_mdpr_codecdata(AVFormatContext *s, AVIOContext *pb,
                                AVStream *st, RMStream *rst,
                                unsigned int codec_data_size, const uint8_t *mime)
  {
      unsigned int v;
      int size;
      int64_t codec_pos;
      int ret;
  
      if (codec_data_size > INT_MAX)
          return AVERROR_INVALIDDATA;
      if (codec_data_size == 0)
          return 0;
  
      avpriv_set_pts_info(st, 64, 1, 1000);
      codec_pos = avio_tell(pb);
      v = avio_rb32(pb);
  
      if (v == MKTAG(0xfd, 'a', 'r', '.')) {
          /* ra type header */
          if (rm_read_audio_stream_info(s, pb, st, rst, 0))
              return -1;
      } else if (v == MKBETAG('L', 'S', 'D', ':')) {
          avio_seek(pb, -4, SEEK_CUR);
          if ((ret = rm_read_extradata(s, pb, st->codecpar, codec_data_size)) < 0)
              return ret;
  
          st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
          st->codecpar->codec_tag  = AV_RL32(st->codecpar->extradata);
          st->codecpar->codec_id   = ff_codec_get_id(ff_rm_codec_tags,
                                                  st->codecpar->codec_tag);
      } else if(mime && !strcmp(mime, "logical-fileinfo")){
          int stream_count, rule_count, property_count, i;
          ff_free_stream(s, st);
          if (avio_rb16(pb) != 0) {
              av_log(s, AV_LOG_WARNING, "Unsupported version\n");
              goto skip;
          }
          stream_count = avio_rb16(pb);
          avio_skip(pb, 6*stream_count);
          rule_count = avio_rb16(pb);
          avio_skip(pb, 2*rule_count);
          property_count = avio_rb16(pb);
          for(i=0; i<property_count; i++){
              uint8_t name[128], val[128];
              avio_rb32(pb);
              if (avio_rb16(pb) != 0) {
                  av_log(s, AV_LOG_WARNING, "Unsupported Name value property version\n");
                  goto skip; //FIXME skip just this one
              }
              get_str8(pb, name, sizeof(name));
              switch(avio_rb32(pb)) {
              case 2: get_strl(pb, val, sizeof(val), avio_rb16(pb));
                  av_dict_set(&s->metadata, name, val, 0);
                  break;
              default: avio_skip(pb, avio_rb16(pb));
              }
          }
      } else {
          int fps;
          if (avio_rl32(pb) != MKTAG('V', 'I', 'D', 'O')) {
          fail1:
              av_log(s, AV_LOG_WARNING, "Unsupported stream type %08x\n", v);
              goto skip;
          }
          st->codecpar->codec_tag = avio_rl32(pb);
          st->codecpar->codec_id  = ff_codec_get_id(ff_rm_codec_tags,
                                                    st->codecpar->codec_tag);
          av_log(s, AV_LOG_TRACE, "%X %X\n", st->codecpar->codec_tag, MKTAG('R', 'V', '2', '0'));
          if (st->codecpar->codec_id == AV_CODEC_ID_NONE)
              goto fail1;
          st->codecpar->width  = avio_rb16(pb);
          st->codecpar->height = avio_rb16(pb);
          avio_skip(pb, 2); // looks like bits per sample
          avio_skip(pb, 4); // always zero?
          st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
          st->need_parsing = AVSTREAM_PARSE_TIMESTAMPS;
          fps = avio_rb32(pb);
  
          if ((ret = rm_read_extradata(s, pb, st->codecpar, codec_data_size - (avio_tell(pb) - codec_pos))) < 0)
              return ret;
  
          if (fps > 0) {
              av_reduce(&st->avg_frame_rate.den, &st->avg_frame_rate.num,
                        0x10000, fps, (1 << 30) - 1);
  #if FF_API_R_FRAME_RATE
              st->r_frame_rate = st->avg_frame_rate;
  #endif
          } else if (s->error_recognition & AV_EF_EXPLODE) {
              av_log(s, AV_LOG_ERROR, "Invalid framerate\n");
              return AVERROR_INVALIDDATA;
          }
      }
  
  skip:
      /* skip codec info */
      size = avio_tell(pb) - codec_pos;
      if (codec_data_size >= size) {
          avio_skip(pb, codec_data_size - size);
      } else {
          av_log(s, AV_LOG_WARNING, "codec_data_size %u < size %d\n", codec_data_size, size);
      }
  
      return 0;
  }
  
  /** this function assumes that the demuxer has already seeked to the start
   * of the INDX chunk, and will bail out if not. */
  static int rm_read_index(AVFormatContext *s)
  {
      AVIOContext *pb = s->pb;
      unsigned int size, n_pkts, str_id, next_off, n, pos, pts;
      AVStream *st;
  
      do {
          if (avio_rl32(pb) != MKTAG('I','N','D','X'))
              return -1;
          size     = avio_rb32(pb);
          if (size < 20)
              return -1;
          avio_skip(pb, 2);
          n_pkts   = avio_rb32(pb);
          str_id   = avio_rb16(pb);
          next_off = avio_rb32(pb);
          for (n = 0; n < s->nb_streams; n++)
              if (s->streams[n]->id == str_id) {
                  st = s->streams[n];
                  break;
              }
          if (n == s->nb_streams) {
              av_log(s, AV_LOG_ERROR,
                     "Invalid stream index %d for index at pos %"PRId64"\n",
                     str_id, avio_tell(pb));
              goto skip;
          } else if ((avio_size(pb) - avio_tell(pb)) / 14 < n_pkts) {
              av_log(s, AV_LOG_ERROR,
                     "Nr. of packets in packet index for stream index %d "
                     "exceeds filesize (%"PRId64" at %"PRId64" = %"PRId64")\n",
                     str_id, avio_size(pb), avio_tell(pb),
                     (avio_size(pb) - avio_tell(pb)) / 14);
              goto skip;
          }
  
          for (n = 0; n < n_pkts; n++) {
              avio_skip(pb, 2);
              pts = avio_rb32(pb);
              pos = avio_rb32(pb);
              avio_skip(pb, 4); /* packet no. */
  
              av_add_index_entry(st, pos, pts, 0, 0, AVINDEX_KEYFRAME);
          }
  
  skip:
          if (next_off && avio_tell(pb) < next_off &&
              avio_seek(pb, next_off, SEEK_SET) < 0) {
              av_log(s, AV_LOG_ERROR,
                     "Non-linear index detected, not supported\n");
              return -1;
          }
      } while (next_off);
  
      return 0;
  }
  
  static int rm_read_header_old(AVFormatContext *s)
  {
      RMDemuxContext *rm = s->priv_data;
      AVStream *st;
  
      rm->old_format = 1;
      st = avformat_new_stream(s, NULL);
      if (!st)
          return -1;
      st->priv_data = ff_rm_alloc_rmstream();
      if (!st->priv_data)
          return AVERROR(ENOMEM);
      return rm_read_audio_stream_info(s, s->pb, st, st->priv_data, 1);
  }
  
  static int rm_read_multi(AVFormatContext *s, AVIOContext *pb,
                           AVStream *st, char *mime)
  {
      int number_of_streams = avio_rb16(pb);
      int number_of_mdpr;
      int i, ret;
      unsigned size2;
      for (i = 0; i<number_of_streams; i++)
          avio_rb16(pb);
      number_of_mdpr = avio_rb16(pb);
      if (number_of_mdpr != 1) {
          avpriv_request_sample(s, "MLTI with multiple (%d) MDPR", number_of_mdpr);
      }
      for (i = 0; i < number_of_mdpr; i++) {
          AVStream *st2;
          if (i > 0) {
              st2 = avformat_new_stream(s, NULL);
              if (!st2) {
                  ret = AVERROR(ENOMEM);
                  return ret;
              }
              st2->id = st->id + (i<<16);
              st2->codecpar->bit_rate = st->codecpar->bit_rate;
              st2->start_time = st->start_time;
              st2->duration   = st->duration;
              st2->codecpar->codec_type = AVMEDIA_TYPE_DATA;
              st2->priv_data = ff_rm_alloc_rmstream();
              if (!st2->priv_data)
                  return AVERROR(ENOMEM);
          } else
              st2 = st;
  
          size2 = avio_rb32(pb);
          ret = ff_rm_read_mdpr_codecdata(s, s->pb, st2, st2->priv_data,
                                          size2, mime);
          if (ret < 0)
              return ret;
      }
      return 0;
  }
  
  static int rm_read_header(AVFormatContext *s)
  {
      RMDemuxContext *rm = s->priv_data;
      AVStream *st;
      AVIOContext *pb = s->pb;
      unsigned int tag;
      int tag_size;
      unsigned int start_time, duration;
      unsigned int data_off = 0, indx_off = 0;
      char buf[128], mime[128];
      int flags = 0;
      int ret = -1;
      unsigned size, v;
      int64_t codec_pos;
  
      tag = avio_rl32(pb);
      if (tag == MKTAG('.', 'r', 'a', 0xfd)) {
          /* very old .ra format */
          return rm_read_header_old(s);
      } else if (tag != MKTAG('.', 'R', 'M', 'F')) {
          return AVERROR(EIO);
      }
  
      tag_size = avio_rb32(pb);
      avio_skip(pb, tag_size - 8);
  
      for(;;) {
          if (avio_feof(pb))
              goto fail;
          tag = avio_rl32(pb);
          tag_size = avio_rb32(pb);
          avio_rb16(pb);
          av_log(s, AV_LOG_TRACE, "tag=%c%c%c%c (%08x) size=%d\n",
                  (tag      ) & 0xff,
                  (tag >>  8) & 0xff,
                  (tag >> 16) & 0xff,
                  (tag >> 24) & 0xff,
                  tag,
                  tag_size);
          if (tag_size < 10 && tag != MKTAG('D', 'A', 'T', 'A'))
              goto fail;
          switch(tag) {
          case MKTAG('P', 'R', 'O', 'P'):
              /* file header */
              avio_rb32(pb); /* max bit rate */
              avio_rb32(pb); /* avg bit rate */
              avio_rb32(pb); /* max packet size */
              avio_rb32(pb); /* avg packet size */
              avio_rb32(pb); /* nb packets */
              duration = avio_rb32(pb); /* duration */
              s->duration = av_rescale(duration, AV_TIME_BASE, 1000);
              avio_rb32(pb); /* preroll */
              indx_off = avio_rb32(pb); /* index offset */
              data_off = avio_rb32(pb); /* data offset */
              avio_rb16(pb); /* nb streams */
              flags = avio_rb16(pb); /* flags */
              break;
          case MKTAG('C', 'O', 'N', 'T'):
              rm_read_metadata(s, pb, 1);
              break;
          case MKTAG('M', 'D', 'P', 'R'):
              st = avformat_new_stream(s, NULL);
              if (!st) {
                  ret = AVERROR(ENOMEM);
                  goto fail;
              }
              st->id = avio_rb16(pb);
              avio_rb32(pb); /* max bit rate */
              st->codecpar->bit_rate = avio_rb32(pb); /* bit rate */
              avio_rb32(pb); /* max packet size */
              avio_rb32(pb); /* avg packet size */
              start_time = avio_rb32(pb); /* start time */
              avio_rb32(pb); /* preroll */
              duration = avio_rb32(pb); /* duration */
              st->start_time = start_time;
              st->duration = duration;
              if(duration>0)
                  s->duration = AV_NOPTS_VALUE;
              get_str8(pb, buf, sizeof(buf)); /* desc */
              get_str8(pb, mime, sizeof(mime)); /* mimetype */
              st->codecpar->codec_type = AVMEDIA_TYPE_DATA;
              st->priv_data = ff_rm_alloc_rmstream();
              if (!st->priv_data)
                  return AVERROR(ENOMEM);
  
              size = avio_rb32(pb);
              codec_pos = avio_tell(pb);
  
              ffio_ensure_seekback(pb, 4);
              v = avio_rb32(pb);
              if (v == MKBETAG('M', 'L', 'T', 'I')) {
                  ret = rm_read_multi(s, s->pb, st, mime);
                  if (ret < 0)
                      goto fail;
                  avio_seek(pb, codec_pos + size, SEEK_SET);
              } else {
                  avio_skip(pb, -4);
                  if (ff_rm_read_mdpr_codecdata(s, s->pb, st, st->priv_data,
                                                size, mime) < 0)
                      goto fail;
              }
  
              break;
          case MKTAG('D', 'A', 'T', 'A'):
              goto header_end;
          default:
              /* unknown tag: skip it */
              avio_skip(pb, tag_size - 10);
              break;
          }
      }
   header_end:
      rm->nb_packets = avio_rb32(pb); /* number of packets */
      if (!rm->nb_packets && (flags & 4))
          rm->nb_packets = 3600 * 25;
      avio_rb32(pb); /* next data header */
  
      if (!data_off)
          data_off = avio_tell(pb) - 18;
      if (indx_off && pb->seekable && !(s->flags & AVFMT_FLAG_IGNIDX) &&
          avio_seek(pb, indx_off, SEEK_SET) >= 0) {
          rm_read_index(s);
          avio_seek(pb, data_off + 18, SEEK_SET);
      }
  
      return 0;
  
  fail:
      rm_read_close(s);
      return ret;
  }
  
  static int get_num(AVIOContext *pb, int *len)
  {
      int n, n1;
  
      n = avio_rb16(pb);
      (*len)-=2;
      n &= 0x7FFF;
      if (n >= 0x4000) {
          return n - 0x4000;
      } else {
          n1 = avio_rb16(pb);
          (*len)-=2;
          return (n << 16) | n1;
      }
  }
  
  /* multiple of 20 bytes for ra144 (ugly) */
  #define RAW_PACKET_SIZE 1000
  
  static int rm_sync(AVFormatContext *s, int64_t *timestamp, int *flags, int *stream_index, int64_t *pos){
      RMDemuxContext *rm = s->priv_data;
      AVIOContext *pb = s->pb;
      AVStream *st;
      uint32_t state=0xFFFFFFFF;
  
      while(!avio_feof(pb)){
          int len, num, i;
          int mlti_id;
          *pos= avio_tell(pb) - 3;
          if(rm->remaining_len > 0){
              num= rm->current_stream;
              mlti_id = 0;
              len= rm->remaining_len;
              *timestamp = AV_NOPTS_VALUE;
              *flags= 0;
          }else{
              state= (state<<8) + avio_r8(pb);
  
              if(state == MKBETAG('I', 'N', 'D', 'X')){
                  int n_pkts, expected_len;
                  len = avio_rb32(pb);
                  avio_skip(pb, 2);
                  n_pkts = avio_rb32(pb);
                  expected_len = 20 + n_pkts * 14;
                  if (len == 20)
                      /* some files don't add index entries to chunk size... */
                      len = expected_len;
                  else if (len != expected_len)
                      av_log(s, AV_LOG_WARNING,
                             "Index size %d (%d pkts) is wrong, should be %d.\n",
                             len, n_pkts, expected_len);
                  len -= 14; // we already read part of the index header
                  if(len<0)
                      continue;
                  goto skip;
              } else if (state == MKBETAG('D','A','T','A')) {
                  av_log(s, AV_LOG_WARNING,
                         "DATA tag in middle of chunk, file may be broken.\n");
              }
  
              if(state > (unsigned)0xFFFF || state <= 12)
                  continue;
              len=state - 12;
              state= 0xFFFFFFFF;
  
              num = avio_rb16(pb);
              *timestamp = avio_rb32(pb);
              mlti_id = (avio_r8(pb)>>1)-1<<16;
              mlti_id = FFMAX(mlti_id, 0);
              *flags = avio_r8(pb); /* flags */
          }
          for(i=0;i<s->nb_streams;i++) {
              st = s->streams[i];
              if (mlti_id + num == st->id)
                  break;
          }
          if (i == s->nb_streams) {
  skip:
              /* skip packet if unknown number */
              avio_skip(pb, len);
              rm->remaining_len = 0;
              continue;
          }
          *stream_index= i;
  
          return len;
      }
      return -1;
  }
  
  static int rm_assemble_video_frame(AVFormatContext *s, AVIOContext *pb,
                                     RMDemuxContext *rm, RMStream *vst,
                                     AVPacket *pkt, int len, int *pseq,
                                     int64_t *timestamp)
  {
      int hdr;
      int seq = 0, pic_num = 0, len2 = 0, pos = 0; //init to silence compiler warning
      int type;
      int ret;
  
      hdr = avio_r8(pb); len--;
      type = hdr >> 6;
  
      if(type != 3){  // not frame as a part of packet
          seq = avio_r8(pb); len--;
      }
      if(type != 1){  // not whole frame
          len2 = get_num(pb, &len);
          pos  = get_num(pb, &len);
          pic_num = avio_r8(pb); len--;
      }
      if(len<0) {
          av_log(s, AV_LOG_ERROR, "Insufficient data\n");
          return -1;
      }
      rm->remaining_len = len;
      if(type&1){     // frame, not slice
          if(type == 3){  // frame as a part of packet
              len= len2;
              *timestamp = pos;
          }
          if(rm->remaining_len < len) {
              av_log(s, AV_LOG_ERROR, "Insufficient remaining len\n");
              return -1;
          }
          rm->remaining_len -= len;
          if(av_new_packet(pkt, len + 9) < 0)
              return AVERROR(EIO);
          pkt->data[0] = 0;
          AV_WL32(pkt->data + 1, 1);
          AV_WL32(pkt->data + 5, 0);
          if ((ret = avio_read(pb, pkt->data + 9, len)) != len) {
              av_packet_unref(pkt);
              av_log(s, AV_LOG_ERROR, "Failed to read %d bytes\n", len);
              return ret < 0 ? ret : AVERROR(EIO);
          }
          return 0;
      }
      //now we have to deal with single slice
  
      *pseq = seq;
      if((seq & 0x7F) == 1 || vst->curpic_num != pic_num){
          if (len2 > ffio_limit(pb, len2)) {
              av_log(s, AV_LOG_ERROR, "Impossibly sized packet\n");
              return AVERROR_INVALIDDATA;
          }
          vst->slices = ((hdr & 0x3F) << 1) + 1;
          vst->videobufsize = len2 + 8*vst->slices + 1;
          av_packet_unref(&vst->pkt); //FIXME this should be output.
          if(av_new_packet(&vst->pkt, vst->videobufsize) < 0)
              return AVERROR(ENOMEM);
          memset(vst->pkt.data, 0, vst->pkt.size);
          vst->videobufpos = 8*vst->slices + 1;
          vst->cur_slice = 0;
          vst->curpic_num = pic_num;
          vst->pktpos = avio_tell(pb);
      }
      if(type == 2)
          len = FFMIN(len, pos);
  
      if(++vst->cur_slice > vst->slices) {
          av_log(s, AV_LOG_ERROR, "cur slice %d, too large\n", vst->cur_slice);
          return 1;
      }
      if(!vst->pkt.data)
          return AVERROR(ENOMEM);
      AV_WL32(vst->pkt.data - 7 + 8*vst->cur_slice, 1);
      AV_WL32(vst->pkt.data - 3 + 8*vst->cur_slice, vst->videobufpos - 8*vst->slices - 1);
      if(vst->videobufpos + len > vst->videobufsize) {
          av_log(s, AV_LOG_ERROR, "outside videobufsize\n");
          return 1;
      }
      if (avio_read(pb, vst->pkt.data + vst->videobufpos, len) != len)
          return AVERROR(EIO);
      vst->videobufpos += len;
      rm->remaining_len-= len;
  
      if (type == 2 || vst->videobufpos == vst->videobufsize) {
          vst->pkt.data[0] = vst->cur_slice-1;
          *pkt= vst->pkt;
          vst->pkt.data= NULL;
          vst->pkt.size= 0;
          vst->pkt.buf = NULL;
          if(vst->slices != vst->cur_slice) //FIXME find out how to set slices correct from the begin
              memmove(pkt->data + 1 + 8*vst->cur_slice, pkt->data + 1 + 8*vst->slices,
                  vst->videobufpos - 1 - 8*vst->slices);
          pkt->size = vst->videobufpos + 8*(vst->cur_slice - vst->slices);
          pkt->pts = AV_NOPTS_VALUE;
          pkt->pos = vst->pktpos;
          vst->slices = 0;
          return 0;
      }
  
      return 1;
  }
  
  static inline void
  rm_ac3_swap_bytes (AVStream *st, AVPacket *pkt)
  {
      uint8_t *ptr;
      int j;
  
      if (st->codecpar->codec_id == AV_CODEC_ID_AC3) {
          ptr = pkt->data;
          for (j=0;j<pkt->size;j+=2) {
              FFSWAP(int, ptr[0], ptr[1]);
              ptr += 2;
          }
      }
  }
  
  static int readfull(AVFormatContext *s, AVIOContext *pb, uint8_t *dst, int n) {
      int ret = avio_read(pb, dst, n);
      if (ret != n) {
          if (ret >= 0) memset(dst + ret, 0, n - ret);
          else          memset(dst      , 0, n);
          av_log(s, AV_LOG_ERROR, "Failed to fully read block\n");
      }
      return ret;
  }
  
  int
  ff_rm_parse_packet (AVFormatContext *s, AVIOContext *pb,
                      AVStream *st, RMStream *ast, int len, AVPacket *pkt,
                      int *seq, int flags, int64_t timestamp)
  {
      RMDemuxContext *rm = s->priv_data;
      int ret;
  
      if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
          rm->current_stream= st->id;
          ret = rm_assemble_video_frame(s, pb, rm, ast, pkt, len, seq, &timestamp);
          if(ret)
              return ret < 0 ? ret : -1; //got partial frame or error
      } else if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
          if ((ast->deint_id == DEINT_ID_GENR) ||
              (ast->deint_id == DEINT_ID_INT4) ||
              (ast->deint_id == DEINT_ID_SIPR)) {
              int x;
              int sps = ast->sub_packet_size;
              int cfs = ast->coded_framesize;
              int h = ast->sub_packet_h;
              int y = ast->sub_packet_cnt;
              int w = ast->audio_framesize;
  
              if (flags & 2)
                  y = ast->sub_packet_cnt = 0;
              if (!y)
                  ast->audiotimestamp = timestamp;
  
              switch (ast->deint_id) {
                  case DEINT_ID_INT4:
                      for (x = 0; x < h/2; x++)
                          readfull(s, pb, ast->pkt.data+x*2*w+y*cfs, cfs);
                      break;
                  case DEINT_ID_GENR:
                      for (x = 0; x < w/sps; x++)
                          readfull(s, pb, ast->pkt.data+sps*(h*x+((h+1)/2)*(y&1)+(y>>1)), sps);
                      break;
                  case DEINT_ID_SIPR:
                      readfull(s, pb, ast->pkt.data + y * w, w);
                      break;
              }
  
              if (++(ast->sub_packet_cnt) < h)
                  return -1;
              if (ast->deint_id == DEINT_ID_SIPR)
                  ff_rm_reorder_sipr_data(ast->pkt.data, h, w);
  
               ast->sub_packet_cnt = 0;
               rm->audio_stream_num = st->index;
               rm->audio_pkt_cnt = h * w / st->codecpar->block_align;
          } else if ((ast->deint_id == DEINT_ID_VBRF) ||
                     (ast->deint_id == DEINT_ID_VBRS)) {
              int x;
              rm->audio_stream_num = st->index;
              ast->sub_packet_cnt = (avio_rb16(pb) & 0xf0) >> 4;
              if (ast->sub_packet_cnt) {
                  for (x = 0; x < ast->sub_packet_cnt; x++)
                      ast->sub_packet_lengths[x] = avio_rb16(pb);
                  rm->audio_pkt_cnt = ast->sub_packet_cnt;
                  ast->audiotimestamp = timestamp;
              } else
                  return -1;
          } else {
              if ((ret = av_get_packet(pb, pkt, len)) < 0)
                  return ret;
              rm_ac3_swap_bytes(st, pkt);
          }
      } else {
          if ((ret = av_get_packet(pb, pkt, len)) < 0)
              return ret;
      }
  
      pkt->stream_index = st->index;
  
  #if 0
      if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
          if(st->codecpar->codec_id == AV_CODEC_ID_RV20){
              int seq= 128*(pkt->data[2]&0x7F) + (pkt->data[3]>>1);
              av_log(s, AV_LOG_DEBUG, "%d %"PRId64" %d\n", *timestamp, *timestamp*512LL/25, seq);
  
              seq |= (timestamp&~0x3FFF);
              if(seq - timestamp >  0x2000) seq -= 0x4000;
              if(seq - timestamp < -0x2000) seq += 0x4000;
          }
      }
  #endif
  
      pkt->pts = timestamp;
      if (flags & 2)
          pkt->flags |= AV_PKT_FLAG_KEY;
  
      return st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO ? rm->audio_pkt_cnt : 0;
  }
  
  int
  ff_rm_retrieve_cache (AVFormatContext *s, AVIOContext *pb,
                        AVStream *st, RMStream *ast, AVPacket *pkt)
  {
      RMDemuxContext *rm = s->priv_data;
  
      av_assert0 (rm->audio_pkt_cnt > 0);
  
      if (ast->deint_id == DEINT_ID_VBRF ||
          ast->deint_id == DEINT_ID_VBRS) {
          int ret = av_get_packet(pb, pkt, ast->sub_packet_lengths[ast->sub_packet_cnt - rm->audio_pkt_cnt]);
          if (ret < 0)
              return ret;
      } else {
          int ret = av_new_packet(pkt, st->codecpar->block_align);
          if (ret < 0)
              return ret;
          memcpy(pkt->data, ast->pkt.data + st->codecpar->block_align * //FIXME avoid this
                 (ast->sub_packet_h * ast->audio_framesize / st->codecpar->block_align - rm->audio_pkt_cnt),
                 st->codecpar->block_align);
      }
      rm->audio_pkt_cnt--;
      if ((pkt->pts = ast->audiotimestamp) != AV_NOPTS_VALUE) {
          ast->audiotimestamp = AV_NOPTS_VALUE;
          pkt->flags = AV_PKT_FLAG_KEY;
      } else
          pkt->flags = 0;
      pkt->stream_index = st->index;
  
      return rm->audio_pkt_cnt;
  }
  
  static int rm_read_packet(AVFormatContext *s, AVPacket *pkt)
  {
      RMDemuxContext *rm = s->priv_data;
      AVStream *st = NULL; // init to silence compiler warning
      int i, len, res, seq = 1;
      int64_t timestamp, pos;
      int flags;
  
      for (;;) {
          if (rm->audio_pkt_cnt) {
              // If there are queued audio packet return them first
              st = s->streams[rm->audio_stream_num];
              res = ff_rm_retrieve_cache(s, s->pb, st, st->priv_data, pkt);
              if(res < 0)
                  return res;
              flags = 0;
          } else {
              if (rm->old_format) {
                  RMStream *ast;
  
                  st = s->streams[0];
                  ast = st->priv_data;
                  timestamp = AV_NOPTS_VALUE;
                  len = !ast->audio_framesize ? RAW_PACKET_SIZE :
                      ast->coded_framesize * ast->sub_packet_h / 2;
                  flags = (seq++ == 1) ? 2 : 0;
                  pos = avio_tell(s->pb);
              } else {
                  len = rm_sync(s, &timestamp, &flags, &i, &pos);
                  if (len > 0)
                      st = s->streams[i];
              }
  
              if (avio_feof(s->pb))
                  return AVERROR_EOF;
              if (len <= 0)
                  return AVERROR(EIO);
  
              res = ff_rm_parse_packet (s, s->pb, st, st->priv_data, len, pkt,
                                        &seq, flags, timestamp);
              if (res < -1)
                  return res;
              if((flags&2) && (seq&0x7F) == 1)
                  av_add_index_entry(st, pos, timestamp, 0, 0, AVINDEX_KEYFRAME);
              if (res)
                  continue;
          }
  
          if(  (st->discard >= AVDISCARD_NONKEY && !(flags&2))
             || st->discard >= AVDISCARD_ALL){
              av_packet_unref(pkt);
          } else
              break;
      }
  
      return 0;
  }
  
  static int rm_read_close(AVFormatContext *s)
  {
      int i;
  
      for (i=0;i<s->nb_streams;i++)
          ff_rm_free_rmstream(s->streams[i]->priv_data);
  
      return 0;
  }
  
  static int rm_probe(AVProbeData *p)
  {
      /* check file header */
      if ((p->buf[0] == '.' && p->buf[1] == 'R' &&
           p->buf[2] == 'M' && p->buf[3] == 'F' &&
           p->buf[4] == 0 && p->buf[5] == 0) ||
          (p->buf[0] == '.' && p->buf[1] == 'r' &&
           p->buf[2] == 'a' && p->buf[3] == 0xfd))
          return AVPROBE_SCORE_MAX;
      else
          return 0;
  }
  
  static int64_t rm_read_dts(AVFormatContext *s, int stream_index,
                                 int64_t *ppos, int64_t pos_limit)
  {
      RMDemuxContext *rm = s->priv_data;
      int64_t pos, dts;
      int stream_index2, flags, len, h;
  
      pos = *ppos;
  
      if(rm->old_format)
          return AV_NOPTS_VALUE;
  
      if (avio_seek(s->pb, pos, SEEK_SET) < 0)
          return AV_NOPTS_VALUE;
  
      rm->remaining_len=0;
      for(;;){
          int seq=1;
          AVStream *st;
  
          len = rm_sync(s, &dts, &flags, &stream_index2, &pos);
          if(len<0)
              return AV_NOPTS_VALUE;
  
          st = s->streams[stream_index2];
          if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
              h= avio_r8(s->pb); len--;
              if(!(h & 0x40)){
                  seq = avio_r8(s->pb); len--;
              }
          }
  
          if((flags&2) && (seq&0x7F) == 1){
              av_log(s, AV_LOG_TRACE, "%d %d-%d %"PRId64" %d\n",
                      flags, stream_index2, stream_index, dts, seq);
              av_add_index_entry(st, pos, dts, 0, 0, AVINDEX_KEYFRAME);
              if(stream_index2 == stream_index)
                  break;
          }
  
          avio_skip(s->pb, len);
      }
      *ppos = pos;
      return dts;
  }
  
  static int rm_read_seek(AVFormatContext *s, int stream_index,
                          int64_t pts, int flags)
  {
      RMDemuxContext *rm = s->priv_data;
  
      if (ff_seek_frame_binary(s, stream_index, pts, flags) < 0)
          return -1;
      rm->audio_pkt_cnt = 0;
      return 0;
  }
  
  
  AVInputFormat ff_rm_demuxer = {
      .name           = "rm",
      .long_name      = NULL_IF_CONFIG_SMALL("RealMedia"),
      .priv_data_size = sizeof(RMDemuxContext),
      .read_probe     = rm_probe,
      .read_header    = rm_read_header,
      .read_packet    = rm_read_packet,
      .read_close     = rm_read_close,
      .read_timestamp = rm_read_dts,
      .read_seek      = rm_read_seek,
  };
  
  AVInputFormat ff_rdt_demuxer = {
      .name           = "rdt",
      .long_name      = NULL_IF_CONFIG_SMALL("RDT demuxer"),
      .priv_data_size = sizeof(RMDemuxContext),
      .read_close     = rm_read_close,
      .flags          = AVFMT_NOFILE,
  };
  
  static int ivr_probe(AVProbeData *p)
  {
      if (memcmp(p->buf, ".R1M\x0\x1\x1", 7) &&
          memcmp(p->buf, ".REC", 4))
          return 0;
  
      return AVPROBE_SCORE_MAX;
  }
  
  static int ivr_read_header(AVFormatContext *s)
  {
      unsigned tag, type, len, tlen, value;
      int i, j, n, count, nb_streams = 0, ret;
      uint8_t key[256], val[256];
      AVIOContext *pb = s->pb;
      AVStream *st;
      int64_t pos, offset, temp;
  
      pos = avio_tell(pb);
      tag = avio_rl32(pb);
      if (tag == MKTAG('.','R','1','M')) {
          if (avio_rb16(pb) != 1)
              return AVERROR_INVALIDDATA;
          if (avio_r8(pb) != 1)
              return AVERROR_INVALIDDATA;
          len = avio_rb32(pb);
          avio_skip(pb, len);
          avio_skip(pb, 5);
          temp = avio_rb64(pb);
          while (!avio_feof(pb) && temp) {
              offset = temp;
              temp = avio_rb64(pb);
          }
          avio_skip(pb, offset - avio_tell(pb));
          if (avio_r8(pb) != 1)
              return AVERROR_INVALIDDATA;
          len = avio_rb32(pb);
          avio_skip(pb, len);
          if (avio_r8(pb) != 2)
              return AVERROR_INVALIDDATA;
          avio_skip(pb, 16);
          pos = avio_tell(pb);
          tag = avio_rl32(pb);
      }
  
      if (tag != MKTAG('.','R','E','C'))
          return AVERROR_INVALIDDATA;
  
      if (avio_r8(pb) != 0)
          return AVERROR_INVALIDDATA;
      count = avio_rb32(pb);
      for (i = 0; i < count; i++) {
          if (avio_feof(pb))
              return AVERROR_INVALIDDATA;
  
          type = avio_r8(pb);
          tlen = avio_rb32(pb);
          avio_get_str(pb, tlen, key, sizeof(key));
          len = avio_rb32(pb);
          if (type == 5) {
              avio_get_str(pb, len, val, sizeof(val));
              av_log(s, AV_LOG_DEBUG, "%s = '%s'\n", key, val);
          } else if (type == 4) {
              av_log(s, AV_LOG_DEBUG, "%s = '0x", key);
              for (j = 0; j < len; j++)
                  av_log(s, AV_LOG_DEBUG, "%X", avio_r8(pb));
              av_log(s, AV_LOG_DEBUG, "'\n");
          } else if (len == 4 && type == 3 && !strncmp(key, "StreamCount", tlen)) {
              nb_streams = value = avio_rb32(pb);
          } else if (len == 4 && type == 3) {
              value = avio_rb32(pb);
              av_log(s, AV_LOG_DEBUG, "%s = %d\n", key, value);
          } else {
              av_log(s, AV_LOG_DEBUG, "Skipping unsupported key: %s\n", key);
              avio_skip(pb, len);
          }
      }
  
      for (n = 0; n < nb_streams; n++) {
          st = avformat_new_stream(s, NULL);
          if (!st)
              return AVERROR(ENOMEM);
          st->priv_data = ff_rm_alloc_rmstream();
          if (!st->priv_data)
              return AVERROR(ENOMEM);
  
          if (avio_r8(pb) != 1)
              return AVERROR_INVALIDDATA;
  
          count = avio_rb32(pb);
          for (i = 0; i < count; i++) {
              if (avio_feof(pb))
                  return AVERROR_INVALIDDATA;
  
              type = avio_r8(pb);
              tlen  = avio_rb32(pb);
              avio_get_str(pb, tlen, key, sizeof(key));
              len  = avio_rb32(pb);
              if (type == 5) {
                  avio_get_str(pb, len, val, sizeof(val));
                  av_log(s, AV_LOG_DEBUG, "%s = '%s'\n", key, val);
              } else if (type == 4 && !strncmp(key, "OpaqueData", tlen)) {
                  ret = ffio_ensure_seekback(pb, 4);
                  if (ret < 0)
                      return ret;
                  if (avio_rb32(pb) == MKBETAG('M', 'L', 'T', 'I')) {
                      ret = rm_read_multi(s, pb, st, NULL);
                  } else {
                      avio_seek(pb, -4, SEEK_CUR);
                      ret = ff_rm_read_mdpr_codecdata(s, pb, st, st->priv_data, len, NULL);
                  }
  
                  if (ret < 0)
                      return ret;
              } else if (type == 4) {
                  int j;
  
                  av_log(s, AV_LOG_DEBUG, "%s = '0x", key);
                  for (j = 0; j < len; j++)
                      av_log(s, AV_LOG_DEBUG, "%X", avio_r8(pb));
                  av_log(s, AV_LOG_DEBUG, "'\n");
              } else if (len == 4 && type == 3 && !strncmp(key, "Duration", tlen)) {
                  st->duration = avio_rb32(pb);
              } else if (len == 4 && type == 3) {
                  value = avio_rb32(pb);
                  av_log(s, AV_LOG_DEBUG, "%s = %d\n", key, value);
              } else {
                  av_log(s, AV_LOG_DEBUG, "Skipping unsupported key: %s\n", key);
                  avio_skip(pb, len);
              }
          }
      }
  
      if (avio_r8(pb) != 6)
          return AVERROR_INVALIDDATA;
      avio_skip(pb, 12);
      avio_skip(pb, avio_rb64(pb) + pos - avio_tell(s->pb));
      if (avio_r8(pb) != 8)
          return AVERROR_INVALIDDATA;
      avio_skip(pb, 8);
  
      return 0;
  }
  
  static int ivr_read_packet(AVFormatContext *s, AVPacket *pkt)
  {
      RMDemuxContext *rm = s->priv_data;
      int ret = AVERROR_EOF, opcode;
      AVIOContext *pb = s->pb;
      unsigned size, index;
      int64_t pos, pts;
  
      if (avio_feof(pb) || rm->data_end)
          return AVERROR_EOF;
  
      pos = avio_tell(pb);
  
      for (;;) {
          if (rm->audio_pkt_cnt) {
              // If there are queued audio packet return them first
              AVStream *st;
  
              st = s->streams[rm->audio_stream_num];
              ret = ff_rm_retrieve_cache(s, pb, st, st->priv_data, pkt);
              if (ret < 0) {
                  return ret;
              }
          } else {
              if (rm->remaining_len) {
                  avio_skip(pb, rm->remaining_len);
                  rm->remaining_len = 0;
              }
  
              if (avio_feof(pb))
                  return AVERROR_EOF;
  
              opcode = avio_r8(pb);
              if (opcode == 2) {
                  AVStream *st;
                  int seq = 1;
  
                  pts = avio_rb32(pb);
                  index = avio_rb16(pb);
                  if (index >= s->nb_streams)
                      return AVERROR_INVALIDDATA;
  
                  avio_skip(pb, 4);
                  size = avio_rb32(pb);
                  avio_skip(pb, 4);
  
                  if (size < 1 || size > INT_MAX/4) {
                      av_log(s, AV_LOG_ERROR, "size %u is invalid\n", size);
                      return AVERROR_INVALIDDATA;
                  }
  
                  st = s->streams[index];
                  ret = ff_rm_parse_packet(s, pb, st, st->priv_data, size, pkt,
                                           &seq, 0, pts);
                  if (ret < -1) {
                      return ret;
                  } else if (ret) {
                      continue;
                  }
  
                  pkt->pos = pos;
                  pkt->pts = pts;
                  pkt->stream_index = index;
              } else if (opcode == 7) {
                  pos = avio_rb64(pb);
                  if (!pos) {
                      rm->data_end = 1;
                      return AVERROR_EOF;
                  }
              } else {
                  av_log(s, AV_LOG_ERROR, "Unsupported opcode=%d at %"PRIX64"\n", opcode, avio_tell(pb) - 1);
                  return AVERROR(EIO);
              }
          }
  
          break;
      }
  
      return ret;
  }
  
  AVInputFormat ff_ivr_demuxer = {
      .name           = "ivr",
      .long_name      = NULL_IF_CONFIG_SMALL("IVR (Internet Video Recording)"),
      .priv_data_size = sizeof(RMDemuxContext),
      .read_probe     = ivr_probe,
      .read_header    = ivr_read_header,
      .read_packet    = ivr_read_packet,
      .read_close     = rm_read_close,
      .extensions     = "ivr",
  };
  