sdt.c

数字电视广播系统mpeg-2的ts流的解复用和分析软件

    {
      p_service->p_first_descriptor = p_descriptor;
    }
    else
    {
      dvbpsi_descriptor_t* p_last_descriptor = p_service->p_first_descriptor;
      while(p_last_descriptor->p_next != NULL)
        p_last_descriptor = p_last_descriptor->p_next;
      p_last_descriptor->p_next = p_descriptor;
    }
  }

  return p_descriptor;
}


/*****************************************************************************
 * dvbpsi_GatherSDTSections
 *****************************************************************************
 * Callback for the subtable demultiplexor.
 *****************************************************************************/
void dvbpsi_GatherSDTSections(dvbpsi_decoder_t * p_psi_decoder,
                              void * p_private_decoder,
                              dvbpsi_psi_section_t * p_section)
{
  dvbpsi_sdt_decoder_t* p_sdt_decoder
                        = (dvbpsi_sdt_decoder_t*)p_private_decoder;
  int b_append = 1;
  int b_reinit = 0;
  unsigned int i;

  DVBPSI_DEBUG_ARG("SDT decoder",
                   "Table version %2d, " "i_table_id %2d, " "i_extension %5d, "
                   "section %3d up to %3d, " "current %1d",
                   p_section->i_version, p_section->i_table_id,
                   p_section->i_extension,
                   p_section->i_number, p_section->i_last_number,
                   p_section->b_current_next);

  if(!p_section->b_syntax_indicator)
  {
    /* Invalid section_syntax_indicator */
    DVBPSI_ERROR("SDT decoder",
                 "invalid section (section_syntax_indicator == 0)");
    b_append = 0;
  }

  /* Now if b_append is true then we have a valid SDT section */
  if(b_append)
  {
    /* TS discontinuity check */
    if(p_psi_decoder->b_discontinuity)
    {
      b_reinit = 1;
      p_psi_decoder->b_discontinuity = 0;
    }
    else
    {
      /* Perform a few sanity checks */
      if(p_sdt_decoder->p_building_sdt)
      {
        if(p_sdt_decoder->p_building_sdt->i_ts_id != p_section->i_extension)
        {
          /* transport_stream_id */
          DVBPSI_ERROR("SDT decoder",
                       "'transport_stream_id' differs"
                       " whereas no TS discontinuity has occured");
          b_reinit = 1;
        }
        else if(p_sdt_decoder->p_building_sdt->i_version
                                                != p_section->i_version)
        {
          /* version_number */
          DVBPSI_ERROR("SDT decoder",
                       "'version_number' differs"
                       " whereas no discontinuity has occured");
          b_reinit = 1;
        }
        else if(p_sdt_decoder->i_last_section_number !=
                                                p_section->i_last_number)
        {
          /* last_section_number */
          DVBPSI_ERROR("SDT decoder",
                       "'last_section_number' differs"
                       " whereas no discontinuity has occured");
          b_reinit = 1;
        }
      }
      else
      {
        if(    (p_sdt_decoder->b_current_valid)
            && (p_sdt_decoder->current_sdt.i_version == p_section->i_version))
        {
          /* Signal a new SDT if the previous one wasn't active */
          if(    (!p_sdt_decoder->current_sdt.b_current_next)
              && (p_section->b_current_next))
          {
            dvbpsi_sdt_t* p_sdt = (dvbpsi_sdt_t*)malloc(sizeof(dvbpsi_sdt_t));

            p_sdt_decoder->current_sdt.b_current_next = 1;
            *p_sdt = p_sdt_decoder->current_sdt;
            p_sdt_decoder->pf_callback(p_sdt_decoder->p_cb_data, p_sdt);
          }

          /* Don't decode since this version is already decoded */
          b_append = 0;
        }
      }
    }
  }

  /* Reinit the decoder if wanted */
  if(b_reinit)
  {
    /* Force redecoding */
    p_sdt_decoder->b_current_valid = 0;
    /* Free structures */
    if(p_sdt_decoder->p_building_sdt)
    {
      free(p_sdt_decoder->p_building_sdt);
      p_sdt_decoder->p_building_sdt = NULL;
    }
    /* Clear the section array */
    for(i = 0; i <= 255; i++)
    {
      if(p_sdt_decoder->ap_sections[i] != NULL)
      {
        dvbpsi_DeletePSISections(p_sdt_decoder->ap_sections[i]);
        p_sdt_decoder->ap_sections[i] = NULL;
      }
    }
  }

  /* Append the section to the list if wanted */
  if(b_append)
  {
    int b_complete;

    /* Initialize the structures if it's the first section received */
    if(!p_sdt_decoder->p_building_sdt)
    {
      p_sdt_decoder->p_building_sdt =
                                (dvbpsi_sdt_t*)malloc(sizeof(dvbpsi_sdt_t));
      dvbpsi_InitSDT(p_sdt_decoder->p_building_sdt,
                     p_section->i_extension,
                     p_section->i_version,
                     p_section->b_current_next,
                     ((uint16_t)(p_section->p_payload_start[0]) << 8)
                     | p_section->p_payload_start[1]);
      p_sdt_decoder->i_last_section_number = p_section->i_last_number;
    }

    /* Fill the section array */
    if(p_sdt_decoder->ap_sections[p_section->i_number] != NULL)
    {
      DVBPSI_DEBUG_ARG("SDT decoder", "overwrite section number %d",
                       p_section->i_number);
      dvbpsi_DeletePSISections(p_sdt_decoder->ap_sections[p_section->i_number]);
    }
    p_sdt_decoder->ap_sections[p_section->i_number] = p_section;

    /* Check if we have all the sections */
    b_complete = 0;
    for(i = 0; i <= p_sdt_decoder->i_last_section_number; i++)
    {
      if(!p_sdt_decoder->ap_sections[i])
        break;

      if(i == p_sdt_decoder->i_last_section_number)
        b_complete = 1;
    }

    if(b_complete)
    {
      /* Save the current information */
      p_sdt_decoder->current_sdt = *p_sdt_decoder->p_building_sdt;
      p_sdt_decoder->b_current_valid = 1;
      /* Chain the sections */
      if(p_sdt_decoder->i_last_section_number)
      {
        for(i = 0; i <= p_sdt_decoder->i_last_section_number - 1; i++)
          p_sdt_decoder->ap_sections[i]->p_next =
                                        p_sdt_decoder->ap_sections[i + 1];
      }
      /* Decode the sections */
      dvbpsi_DecodeSDTSections(p_sdt_decoder->p_building_sdt,
                               p_sdt_decoder->ap_sections[0]);
      /* Delete the sections */
      dvbpsi_DeletePSISections(p_sdt_decoder->ap_sections[0]);
      /* signal the new SDT */
      p_sdt_decoder->pf_callback(p_sdt_decoder->p_cb_data,
                                 p_sdt_decoder->p_building_sdt);
      /* Reinitialize the structures */
      p_sdt_decoder->p_building_sdt = NULL;
      for(i = 0; i <= p_sdt_decoder->i_last_section_number; i++)
        p_sdt_decoder->ap_sections[i] = NULL;
    }
  }
  else
  {
    dvbpsi_DeletePSISections(p_section);
  }
}


/*****************************************************************************
 * dvbpsi_DecodeSDTSection
 *****************************************************************************
 * SDT decoder.
 *****************************************************************************/
void dvbpsi_DecodeSDTSections(dvbpsi_sdt_t* p_sdt,
                               dvbpsi_psi_section_t* p_section)
{
  uint8_t* p_byte, * p_end;

  while(p_section)
  {
    for(p_byte = p_section->p_payload_start + 3;
        p_byte < p_section->p_payload_end;)
    {
      uint16_t i_service_id = ((uint16_t)(p_byte[0]) << 8) | p_byte[1];
      int b_eit_schedule = (int)((p_byte[2]) & 0x2 >> 1);
      int b_eit_present = (int)((p_byte[2]) & 0x1);
      uint8_t i_running_status = (uint8_t)(p_byte[3]) >> 5;
      int b_free_ca = (int)(p_byte[3]) & 0x10 >> 4;
      uint16_t i_length = ((uint16_t)(p_byte[3] & 0xf) <<8) | p_byte[4];
      dvbpsi_sdt_service_t* p_service = dvbpsi_SDTAddService(p_sdt,
          i_service_id, b_eit_schedule, b_eit_present,
          i_running_status, b_free_ca);
      /* Service descriptors */
      p_byte += 5;
      p_end = p_byte + i_length;
      while(p_byte + 2 < p_end)
      {
        uint8_t i_tag = p_byte[0];
        uint8_t i_length = p_byte[1];
        if(i_length + 2 <= p_end - p_byte)
          dvbpsi_SDTServiceAddDescriptor(p_service, i_tag, i_length, p_byte + 2);
        p_byte += 2 + i_length;
      }
    }

    p_section = p_section->p_next;
  }
}