pmt.c

Dvbstreamer 用在解析MPTS的部分内容

          /* Signal a new PMT if the previous one wasn't active */
          if(    (!p_pmt_decoder->current_pmt.b_current_next)
              && (p_section->b_current_next))
          {
            dvbpsi_pmt_t* p_pmt = (dvbpsi_pmt_t*)ObjectCreateType(dvbpsi_pmt_t);

            p_pmt_decoder->current_pmt.b_current_next = 1;
            *p_pmt = p_pmt_decoder->current_pmt;
            p_pmt_decoder->pf_callback(p_pmt_decoder->p_cb_data, p_pmt);
          }

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

  /* Reinit the decoder if wanted */
  if(b_reinit)
  {
    /* Force redecoding */
    p_pmt_decoder->b_current_valid = 0;
    /* Free structures */
    if(p_pmt_decoder->p_building_pmt)
    {
      ObjectRefDec(p_pmt_decoder->p_building_pmt);
      p_pmt_decoder->p_building_pmt = NULL;
    }
    /* Clear the section array */
    for(i = 0; i <= 255; i++)
    {
      if(p_pmt_decoder->ap_sections[i] != NULL)
      {
        dvbpsi_ReleasePSISections(p_decoder, p_pmt_decoder->ap_sections[i]);
        p_pmt_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_pmt_decoder->p_building_pmt)
    {
      dvbpsi_NewPMT(p_pmt_decoder->p_building_pmt,
                     p_pmt_decoder->i_program_number,
                     p_section->i_version,
                     p_section->b_current_next,
                       ((uint16_t)(p_section->p_payload_start[0] & 0x1f) << 8)
                     | p_section->p_payload_start[1]);
      p_pmt_decoder->i_last_section_number = p_section->i_last_number;
    }

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

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

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

    if(b_complete)
    {
      /* Save the current information */
      p_pmt_decoder->current_pmt = *p_pmt_decoder->p_building_pmt;
      p_pmt_decoder->b_current_valid = 1;
      /* Chain the sections */
      if(p_pmt_decoder->i_last_section_number)
      {
        for(i = 0; i <= p_pmt_decoder->i_last_section_number - 1; i++)
          p_pmt_decoder->ap_sections[i]->p_next =
                                        p_pmt_decoder->ap_sections[i + 1];
      }
      /* Decode the sections */
      dvbpsi_DecodePMTSections(p_pmt_decoder->p_building_pmt,
                               p_pmt_decoder->ap_sections[0]);
      /* Delete the sections */
      dvbpsi_ReleasePSISections(p_decoder, p_pmt_decoder->ap_sections[0]);
      /* signal the new PMT */
      p_pmt_decoder->pf_callback(p_pmt_decoder->p_cb_data,
                                 p_pmt_decoder->p_building_pmt);
      /* Reinitialize the structures */
      p_pmt_decoder->p_building_pmt = NULL;
      for(i = 0; i <= p_pmt_decoder->i_last_section_number; i++)
        p_pmt_decoder->ap_sections[i] = NULL;
    }
  }
  else
  {
    dvbpsi_ReleasePSISections(p_decoder, p_section);
  }
}


/*****************************************************************************
 * dvbpsi_DecodePMTSections
 *****************************************************************************
 * PMT decoder.
 *****************************************************************************/
void dvbpsi_DecodePMTSections(dvbpsi_pmt_t* p_pmt,
                              dvbpsi_psi_section_t* p_section)
{
  uint8_t* p_byte, * p_end;

  while(p_section)
  {
    /* - PMT descriptors */
    p_byte = p_section->p_payload_start + 4;
    p_end = p_byte + (   ((uint16_t)(p_section->p_payload_start[2] & 0x0f) << 8)
                       | p_section->p_payload_start[3]);
    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_PMTAddDescriptor(p_pmt, i_tag, i_length, p_byte + 2);
      p_byte += 2 + i_length;
    }

    /* - ESs */
    for(p_byte = p_end; p_byte + 5 <= p_section->p_payload_end;)
    {
      uint8_t i_type = p_byte[0];
      uint16_t i_pid = ((uint16_t)(p_byte[1] & 0x1f) << 8) | p_byte[2];
      uint16_t i_length = ((uint16_t)(p_byte[3] & 0x0f) << 8) | p_byte[4];
      dvbpsi_pmt_es_t* p_es = dvbpsi_PMTAddES(p_pmt, i_type, i_pid);
      /* - ES descriptors */
      p_byte += 5;
      p_end = p_byte + i_length;
      if( p_end > p_section->p_payload_end )
      {
            p_end = p_section->p_payload_end;
      }
      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_PMTESAddDescriptor(p_es, i_tag, i_length, p_byte + 2);
        p_byte += 2 + i_length;
      }
    }

    p_section = p_section->p_next;
  }
}


/*****************************************************************************
 * dvbpsi_GenPMTSections
 *****************************************************************************
 * Generate PMT sections based on the dvbpsi_pmt_t structure.
 *****************************************************************************/
dvbpsi_psi_section_t* dvbpsi_GenPMTSections(dvbpsi_pmt_t* p_pmt)
{
  dvbpsi_psi_section_t* p_result = dvbpsi_NewPSISection(1024);
  dvbpsi_psi_section_t* p_current = p_result;
  dvbpsi_psi_section_t* p_prev;
  dvbpsi_descriptor_t* p_descriptor = p_pmt->p_first_descriptor;
  dvbpsi_pmt_es_t* p_es = p_pmt->p_first_es;
  uint16_t i_info_length;

  p_current->i_table_id = 0x02;
  p_current->b_syntax_indicator = 1;
  p_current->b_private_indicator = 0;
  p_current->i_length = 13;                     /* header + CRC_32 */
  p_current->i_extension = p_pmt->i_program_number;
  p_current->i_version = p_pmt->i_version;
  p_current->b_current_next = p_pmt->b_current_next;
  p_current->i_number = 0;
  p_current->p_payload_end += 12;               /* just after the header */
  p_current->p_payload_start = p_current->p_data + 8;

  /* PCR_PID */
  p_current->p_data[8] = (p_pmt->i_pcr_pid >> 8) | 0xe0;
  p_current->p_data[9] = p_pmt->i_pcr_pid;

  /* PMT descriptors */
  while(p_descriptor != NULL)
  {
    /* New section if needed */
    /* written_data_length + descriptor_length + 2 > 1024 - CRC_32_length */
    if(   (p_current->p_payload_end - p_current->p_data)
                                + p_descriptor->i_length > 1018)
    {
      /* program_info_length */
      i_info_length = (p_current->p_payload_end - p_current->p_data) - 12;
      p_current->p_data[10] = (i_info_length >> 8) | 0xf0;
      p_current->p_data[11] = i_info_length;

      p_prev = p_current;
      p_current = dvbpsi_NewPSISection(1024);
      p_prev->p_next = p_current;

      p_current->i_table_id = 0x02;
      p_current->b_syntax_indicator = 1;
      p_current->b_private_indicator = 0;
      p_current->i_length = 13;                 /* header + CRC_32 */
      p_current->i_extension = p_pmt->i_program_number;
      p_current->i_version = p_pmt->i_version;
      p_current->b_current_next = p_pmt->b_current_next;
      p_current->i_number = p_prev->i_number + 1;
      p_current->p_payload_end += 12;           /* just after the header */
      p_current->p_payload_start = p_current->p_data + 8;

      /* PCR_PID */
      p_current->p_data[8] = (p_pmt->i_pcr_pid >> 8) | 0xe0;
      p_current->p_data[9] = p_pmt->i_pcr_pid;
    }

    /* p_payload_end is where the descriptor begins */
    p_current->p_payload_end[0] = p_descriptor->i_tag;
    p_current->p_payload_end[1] = p_descriptor->i_length;
    memcpy(p_current->p_payload_end + 2,
           p_descriptor->p_data,
           p_descriptor->i_length);

    /* Increase length by descriptor_length + 2 */
    p_current->p_payload_end += p_descriptor->i_length + 2;
    p_current->i_length += p_descriptor->i_length + 2;

    p_descriptor = p_descriptor->p_next;
  }

  /* program_info_length */
  i_info_length = (p_current->p_payload_end - p_current->p_data) - 12;
  p_current->p_data[10] = (i_info_length >> 8) | 0xf0;
  p_current->p_data[11] = i_info_length;

  /* PMT ESs */
  while(p_es != NULL)
  {
    uint8_t* p_es_start = p_current->p_payload_end;
    uint16_t i_es_length = 5;

    /* Can the current section carry all the descriptors ? */
    p_descriptor = p_es->p_first_descriptor;
    while(    (p_descriptor != NULL)
           && ((p_es_start - p_current->p_data) + i_es_length <= 1020))
    {
      i_es_length += p_descriptor->i_length + 2;
      p_descriptor = p_descriptor->p_next;
    }

    /* If _no_ and the current section isn't empty and an empty section
       may carry one more descriptor
       then create a new section */
    if(    (p_descriptor != NULL)
        && (p_es_start - p_current->p_data != 12)
        && (i_es_length <= 1008))
    {
      /* will put more descriptors in an empty section */
      DVBPSI_DEBUG("PMT generator",
                   "create a new section to carry more ES descriptors");
      p_prev = p_current;
      p_current = dvbpsi_NewPSISection(1024);
      p_prev->p_next = p_current;

      p_current->i_table_id = 0x02;
      p_current->b_syntax_indicator = 1;
      p_current->b_private_indicator = 0;
      p_current->i_length = 13;                 /* header + CRC_32 */
      p_current->i_extension = p_pmt->i_program_number;
      p_current->i_version = p_pmt->i_version;
      p_current->b_current_next = p_pmt->b_current_next;
      p_current->i_number = p_prev->i_number + 1;
      p_current->p_payload_end += 12;           /* just after the header */
      p_current->p_payload_start = p_current->p_data + 8;

      /* PCR_PID */
      p_current->p_data[8] = (p_pmt->i_pcr_pid >> 8) | 0xe0;
      p_current->p_data[9] = p_pmt->i_pcr_pid;

      /* program_info_length */
      i_info_length = 0;
      p_current->p_data[10] = 0xf0;
      p_current->p_data[11] = 0x00;

      p_es_start = p_current->p_payload_end;
    }

    /* p_es_start is where the ES begins */
    p_es_start[0] = p_es->i_type;
    p_es_start[1] = (p_es->i_pid >> 8) | 0xe0;
    p_es_start[2] = p_es->i_pid;

    /* Increase the length by 5 */
    p_current->p_payload_end += 5;
    p_current->i_length += 5;

    /* ES descriptors */
    p_descriptor = p_es->p_first_descriptor;
    while(    (p_descriptor != NULL)
           && (   (p_current->p_payload_end - p_current->p_data)
                + p_descriptor->i_length <= 1018))
    {
      /* p_payload_end is where the descriptor begins */
      p_current->p_payload_end[0] = p_descriptor->i_tag;
      p_current->p_payload_end[1] = p_descriptor->i_length;
      memcpy(p_current->p_payload_end + 2,
             p_descriptor->p_data,
             p_descriptor->i_length);

      /* Increase length by descriptor_length + 2 */
      p_current->p_payload_end += p_descriptor->i_length + 2;
      p_current->i_length += p_descriptor->i_length + 2;

      p_descriptor = p_descriptor->p_next;
    }

    if(p_descriptor != NULL)
      DVBPSI_ERROR("PMT generator", "unable to carry all the ES descriptors");

    /* ES_info_length */
    i_es_length = p_current->p_payload_end - p_es_start - 5;
    p_es_start[3] = (i_es_length >> 8) | 0xf0;
    p_es_start[4] = i_es_length;

    p_es = p_es->p_next;
  }

  /* Finalization */
  p_prev = p_result;
  while(p_prev != NULL)
  {
    p_prev->i_last_number = p_current->i_number;
    dvbpsi_BuildPSISection(p_prev);
    p_prev = p_prev->p_next;
  }

  return p_result;
}