Structure of Transport Stream (from ISO/IEC 13818-1):

transport_packet() {
  sync_byte                                   8    bslbf       0
  transport_error_indicator                   1    bslbf       1
  payload_unit_start_indicator                1    bslbf       1
  transport_priority                          1    bslbf       1
  PID                                         13   uimsbf      1,2
  transport_scrambling_control                2    bslbf       3
  adaption_field_control                      2    bslbf       3
  continuity_counter                          4    uimsbf      3
  if (adaption_field_control=='10' || adaption_field_control=='11'){
      adaption_field()
  }
  if (adaption_field_control=='01' || adaption_field_control=='11'){
      for (i=0;i<N;i++){
        data_byte                             8    bslbf
      }
  }
}

Structure of Packetized Elementary Stream (from ISO/IEC 13818-1):

This is a simplified version of the full description available in the
standard document.

PES_packet() {
  packet_start_code_prefix                   24    bslbf
  stream_id                                   8    uimsbf
  PES_packet_length                          16    uimsbf
  if( stream_id!=program_stream_map
   && stream_id!=padding_stream
   && stream_id!=private_stream_2
   && stream_id!=ECM
   && stream_id!=EMM
   && stream_id!=program_stream_directory
   && stream_id!=DSMCC_stream
   && stream_id!=ITU-T Rec. H222.1 type E_stream) {
      '10'                                    2    bslbf
      PES_scrambling_control                  2    bslbf
      PES_priority                            1    bslbf
      data_alignment_indicator                1    bslbf
      copyright                               1    bslbf
      original_or_copy                        1    bslbf

      PTS_DTS_flags                           2    bslbf
      ESCR_flag                               1    bslbf
      ES_rate_flag                            1    bslbf
      DSM_trick_mode_flag                     1    bslbf
      additional_copy_info_flag               1    bslbf
      PES_CRC_flag                            1    bslbf
      PES_extension_flag                      1    bslbf

      PES_header_data_length                  8    uimsbf
      
      if( PTS_DTS_flags=='10') {
          [5 bytes containing 33-bit PTS]
      }
      if( PTS_DTS_flags=='11') {
          [10 bytes containing 33-bit PTS then 33-bit DTS]
      }
      if( ESCR_flag=='1') {
          [6 bytes containing 33-bit ESCR]
      }
      if( ES_rate_flag=='1') {
          [3 bytes containing 22-bit ES_rate]
      }
      if( DSM_trick_mode_flag=='1') {
          [Variable number of bytes]
      }
      if( additional_copy_info_flag=='1') {
          marker_bit                          1   bslbf
          additional_copy_info                7   bslbf
      }
      if (PES_CRC_flag=='1') {
          previous_PES_packet_CRC            16   bslbf
      }
      if (PES_extension_flag=='1') {
         [Variable number of bytes]
      }
      for (i=0;i<N1;i++) {
         stuffing_byte                        8   bslbf
      }
      for (i=0;i<N2;i++) {
         PES_packet_data_byte                 8   bslbf
      }
  }
  else if( stream_id==program_stream_map
   || stream_id==private_stream_2
   || stream_id==ECM
   || stream_id==EMM
   || stream_id==program_stream_directory
   || stream_id==DSMCC_stream
   || stream_id==ITU-T Rec. H222.1 type E_stream) {
  } 
      for (i=0;i<PES_packet_length;i++) {
         PES_packet_data_byte                 8   bslbf
      }
  }         
  else if (stream_id==padding_stream) {
  } 
      for (i=0;i<PES_packet_length;i++) {
         padding_byte                         8   bslbf
      }
  }
}