The SDT provides information about services in current or other transport streams. The identification is done via the table_id. Tables for the current transport stream using table_id 0x42, for other transport streams table_id 0x46. The flags in the SDT to indicate whether the service is scrambled or Free to Air, what the status is and whether the service has EIT p / f and schedule. It is preferred to keep service IDs once assigned to a service, to make functions such as favorites lists possible.
TR 101 290
  • The repetition rate must be less than 3 seconds for the actual SDT, SDT-other for 10 seconds.
  • The time between receiving the last byte of the section and the first byte of the next section should be at least 25 ms.
  • The Scrambling Control must have the binary value '00' (umscrambled)
  • Descriptors
    The following descriptors may appear in the SDT :
  • stuffing_descriptor
  • bouquet_name_descriptor
  • service_descriptor
  • country_availability_descriptor
  • linkage_descriptor
  • NVOD_reference_descriptor
  • time_shifted_service_descriptor
  • component_descriptor
  • mosaic_descriptor
  • CA_identifier_descriptor
  • telephone_descriptor
  • multilingual_service_name_descriptor
  • private_data_specifier_descriptor
  • data_broadcast_descriptor
  • announcement_support_descriptor
  • service_identifier_descriptor
  • service_availability_descriptor
  • default_authority_descriptor
  • extension_descriptor

  • name bits description
    Table ID 8 Indicates to which table this section belongs, in this case SDT-actual = information on the current transport stream (0x42). In the case of SDT-other (0x46) = Information about other transport stream
    section_syntax_indicator 1 Indicates whether a sub-table structure including CRC check is used.
    reserved_for_future_use 1 always binary value '0'
    Reserved 2 always binary value '11'
    Section length 12 The length of the section in bytes. This length starts immediately after this field and includes the CRC.
    Transport_stream_id 16 Indicates on which transport stream this SDT informs.
    reserved 2 always binary value '11'
    version_number 5 Value between 0 to 31.
    A higher value indicates that the information has changed.
    current_next_indicator 1 This is to indicate whether a section is 'valid now' or 'valid in future'
    section_number 8 Value between 0x00 - 0xFF. Used to indicate the sections of a table. Up to 256 sections.
    last_section_number 8 The number of the last section, so the receiver know when the table is completely received.
    Original Network ID 16 This 16-bit field indicates the network ID of the original network
    reserved for future use 8 always binary value '11111111'
    Service Loop
    service id 16 This 16 bit field gives the service ID for identification of the service in the Transport stream
    reserved for future use 6 always binary value '111111'
    EIT schedule flag 1 If this bit field has value 1 EIT schedule information is available for this service in the transport stream
    EIT present following flag 1 If this bit field has value 1 EIT present following information is available for this service in the transport stream
    running status 3 This field gives information about the service Status. 000 = undefined, 001 = not running, 010 = start in a few seconds, 011 = pause, 100 = running, 101 - 111 reserved for future use
    free CA mode 1 If this 1 bit field has value 1 access to one or more components is controlled by a CA system.
    descriptor loop length 12 The length of the Descriptor loop
    Service descriptors loop
    CRC_32 32 Cyclic redundancy check