atsc_eit.c

Dvbstreamer 用在解析MPTS的部分内容

                                               uint8_t *p_data)
{
  dvbpsi_descriptor_t * p_descriptor
                        = dvbpsi_NewDescriptor(i_tag, i_length, p_data);

  if(p_descriptor)
  {
    if(p_event->p_first_descriptor == NULL)
    {
      p_event->p_first_descriptor = p_descriptor;
    }
    else
    {
      dvbpsi_descriptor_t * p_last_descriptor = p_event->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_atsc_GatherEITSections
 *****************************************************************************
 * Callback for the subtable demultiplexor.
 *****************************************************************************/
void dvbpsi_atsc_GatherEITSections(dvbpsi_decoder_t * p_psi_decoder,
                              void * p_private_decoder,
                              dvbpsi_psi_section_t * p_section)
{
  dvbpsi_atsc_eit_decoder_t * p_eit_decoder
                        = (dvbpsi_atsc_eit_decoder_t*)p_private_decoder;
  int b_append = 1;
  int b_reinit = 0;
  unsigned int i;

  DVBPSI_DEBUG_ARG("EIT 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("EIT decoder",
                 "invalid section (section_syntax_indicator == 0)");
    b_append = 0;
  }

  /* Now if b_append is true then we have a valid EIT 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_eit_decoder->p_building_eit)
      {
        if(p_eit_decoder->p_building_eit->i_source_id != p_section->i_extension)
        {
          /* transport_stream_id */
          DVBPSI_ERROR("EIT decoder",
                       "'transport_stream_id' differs"
                       " whereas no TS discontinuity has occured");
          b_reinit = 1;
        }
        else if(p_eit_decoder->p_building_eit->i_version
                                                != p_section->i_version)
        {
          /* version_number */
          DVBPSI_ERROR("EIT decoder",
                       "'version_number' differs"
                       " whereas no discontinuity has occured");
          b_reinit = 1;
        }
        else if(p_eit_decoder->i_last_section_number !=
                                                p_section->i_last_number)
        {
          /* last_section_number */
          DVBPSI_ERROR("EIT decoder",
                       "'last_section_number' differs"
                       " whereas no discontinuity has occured");
          b_reinit = 1;
        }
      }
      else
      {
        if(    (p_eit_decoder->b_current_valid)
            && (p_eit_decoder->current_eit.i_version == p_section->i_version))
        {
          /* Signal a new EIT if the previous one wasn't active */
          if(    (!p_eit_decoder->current_eit.b_current_next)
              && (p_section->b_current_next))
          {
            dvbpsi_atsc_eit_t * p_eit = (dvbpsi_atsc_eit_t*)ObjectCreateType(dvbpsi_atsc_eit_t);

            p_eit_decoder->current_eit.b_current_next = 1;
            *p_eit = p_eit_decoder->current_eit;
            p_eit_decoder->pf_callback(p_eit_decoder->p_cb_data, p_eit);
          }

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

  /* Reinit the decoder if wanted */
  if(b_reinit)
  {
    /* Force redecoding */
    p_eit_decoder->b_current_valid = 0;
    /* Free structures */
    if(p_eit_decoder->p_building_eit)
    {
      ObjectRefDec(p_eit_decoder->p_building_eit);
      p_eit_decoder->p_building_eit = NULL;
    }
    /* Clear the section array */
    for(i = 0; i <= 255; i++)
    {
      if(p_eit_decoder->ap_sections[i] != NULL)
      {
        dvbpsi_ReleasePSISections(p_psi_decoder, p_eit_decoder->ap_sections[i]);
        p_eit_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_eit_decoder->p_building_eit)
    {
      dvbpsi_atsc_NewEIT(p_eit_decoder->p_building_eit,
                     p_section->i_version,
                     p_section->b_current_next,
                     p_section->p_payload_start[0],
                     p_section->i_extension);
      p_eit_decoder->i_last_section_number = p_section->i_last_number;
    }

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

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

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

    if(b_complete)
    {
      /* Save the current information */
      p_eit_decoder->current_eit = *p_eit_decoder->p_building_eit;
      p_eit_decoder->b_current_valid = 1;
      /* Chain the sections */
      if(p_eit_decoder->i_last_section_number)
      {
        for(i = 0; i <= p_eit_decoder->i_last_section_number - 1; i++)
          p_eit_decoder->ap_sections[i]->p_next =
                                        p_eit_decoder->ap_sections[i + 1];
      }
      /* Decode the sections */
      dvbpsi_atsc_DecodeEITSections(p_eit_decoder->p_building_eit,
                               p_eit_decoder->ap_sections[0]);
      /* Delete the sections */
      dvbpsi_ReleasePSISections(p_psi_decoder,p_eit_decoder->ap_sections[0]);
      /* signal the new EIT */
      p_eit_decoder->pf_callback(p_eit_decoder->p_cb_data,
                                 p_eit_decoder->p_building_eit);
      /* Reinitialize the structures */
      p_eit_decoder->p_building_eit = NULL;
      for(i = 0; i <= p_eit_decoder->i_last_section_number; i++)
        p_eit_decoder->ap_sections[i] = NULL;
    }
  }
  else
  {
    dvbpsi_ReleasePSISections(p_psi_decoder,p_section);
  }
}


/*****************************************************************************
 * dvbpsi_DecodeEITSection
 *****************************************************************************
 * EIT decoder.
 *****************************************************************************/
void dvbpsi_atsc_DecodeEITSections(dvbpsi_atsc_eit_t* p_eit,
                              dvbpsi_psi_section_t* p_section)
{
  uint8_t *p_byte, *p_end;

  while(p_section)
  {
    uint16_t i_number_events = p_section->p_payload_start[1];
    uint16_t i_events_count = 0;
    uint16_t i_length = 0;
    
    for(p_byte = p_section->p_payload_start + 2; 
        ((p_byte + 4) < p_section->p_payload_end) && (i_events_count < i_number_events); 
        i_events_count ++)
    {
        dvbpsi_atsc_eit_event_t* p_event;
        uint16_t i_event_id          = ((uint16_t)(p_byte[0] & 0x3f) << 8) | ((uint16_t) p_byte[1]);
        uint32_t i_start_time        = ((uint32_t)(p_byte[2] << 24)) |
                                       ((uint32_t)(p_byte[3] << 16)) |
                                       ((uint32_t)(p_byte[4] <<  8)) |
                                       ((uint32_t)(p_byte[5]));
        uint8_t  i_etm_location      = (uint8_t)((p_byte[6] & 0x30) >> 4);
        uint32_t i_length_seconds    = ((uint32_t)((p_byte[6] & 0x0f) << 16)) |
                                       ((uint32_t)(p_byte[7] << 8)) |
                                       ((uint32_t)(p_byte[8]));
        uint8_t  i_title_length      = p_byte[9];

        p_byte += 10;
        p_event = dvbpsi_atsc_EITAddEvent(p_eit, i_event_id, i_start_time, 
                                i_etm_location, i_length_seconds, i_title_length, 
                                p_byte);
        p_byte += i_title_length;
        i_length = ((uint16_t)(p_byte[0] & 0xf) <<8) | p_byte[1];
        /* Table descriptors */
        p_byte += 2;
        p_end = p_byte + i_length;
        if( p_end > p_section->p_payload_end ) break;

        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_atsc_EITChannelAddDescriptor(p_event, i_tag, i_length, p_byte + 2);
            p_byte += 2 + i_length;
        }
    }

    p_section = p_section->p_next;
  }
}