ETSI TS 101 211 V1.12.1 (2013-12)

Technical Specification
Digital Video Broadcasting (DVB);
Guidelines on implementation and usage
of Service Information (SI)
2 ETSI TS 101 211 V1.12.1 (2013-12)

Reference
RTS/JTC-DVB-330
Keywords
broadcasting, digital, DVB, MPEG, TV, video
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: +33 4 92 94 42 00  Fax: +33 4 93 65 47 16

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

Important notice
Individual copies of the present document can be downloaded from:
http://www.etsi.org
The present document may be made available in more than one electronic version or in print. In any case of existing or
perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF).
In case of dispute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive
within ETSI Secretariat.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
http://portal.etsi.org/tb/status/status.asp
If you find errors in the present document, please send your comment to one of the following services:
http://portal.etsi.org/chaircor/ETSI_support.asp
Copyright Notification
No part may be reproduced except as authorized by written permission.
The copyright and the foregoing restriction extend to reproduction in all media.

© European Telecommunications Standards Institute 2013.
© European Broadcasting Union 2013.
All rights reserved.
TM TM TM
DECT , PLUGTESTS , UMTS and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members.
TM
3GPP and LTE™ are Trade Marks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
GSM® and the GSM logo are Trade Marks registered and owned by the GSM Association.
ETSI
3 ETSI TS 101 211 V1.12.1 (2013-12)
Contents
Intellectual Property Rights . 6
Foreword . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 7
3 Definitions and abbreviations . 9
3.1 Definitions . 9
3.2 Abbreviations . 10
4 Rules of operation . 11
4.1 Service Information (SI) table information . 12
4.1.1 Network Information Table (NIT) information . 12
4.1.2 Bouquet Association Table (BAT) information . 13
4.1.3 Service Description Table (SDT) information . 14
4.1.4 Event Information Table (EIT) information . 14
4.1.4.1 EIT Present/Following information . 14
4.1.4.2 EIT Schedule information . 16
4.1.4.2.1 EIT Schedule structure . 16
4.1.4.2.2 EIT scrambling . 17
4.1.5 Time and Date Table (TDT) . 17
4.1.6 Time Offset Table (TOT) . 17
4.1.7 Running Status Table (RST) . 17
4.1.8 Stuffing Table (ST) . 17
4.1.9 Transport Stream Description Table (TSDT) . 17
4.1.9.1 Digital Satellite News Gathering (DSNG) . 18
4.1.10 Table update mechanism . 18
4.1.11 Table segmentation . 19
4.1.11.1 Generic segmentation rules . 19
4.1.11.1.1 General rules . 19
4.1.11.1.2 NIT and BAT . 19
4.1.11.1.3 SDT and EIT . 19
4.1.11.2 Segmentation rules for DVB-H and DVB-SH systems . 19
4.1.11.2.1 General rules . 19
4.1.11.2.2 NIT and BAT for DVB-SH and DVB-H . 19
4.1.11.2.3 SDT for DVB-SH and DVB-H . 21
4.2 SI descriptor allocation and usage . 21
4.2.1 Descriptors of the Network Information Table (NIT) . 21
4.2.1.1 First descriptor loop . 21
4.2.1.1.1 Linkage descriptor . 21
4.2.1.1.2 Multilingual network name descriptor . 22
4.2.1.1.3 Network name descriptor. 22
4.2.1.1.4 Cell list descriptor. 22
4.2.1.1.5 Network change notify descriptor . 22
4.2.1.1.6 URI linkage descriptor . 23
4.2.1.2 Second descriptor loop . 23
4.2.1.2.1 Delivery system descriptors . 23
4.2.1.2.2 Service list descriptor . 23
4.2.1.2.3 Frequency list descriptor . 23
4.2.1.2.4 Cell frequency link descriptor . 23
4.2.2 Descriptors of the Bouquet Association Table (BAT) . 24
4.2.2.1 First descriptor loop . 24
4.2.2.1.1 Bouquet name descriptor . 24
4.2.2.1.2 CA identifier descriptor . 24
4.2.2.1.3 Country availability descriptor . 24
ETSI
4 ETSI TS 101 211 V1.12.1 (2013-12)
4.2.2.1.4 Linkage descriptor . 24
4.2.2.1.5 Multilingual bouquet name descriptor . 25
4.2.2.2 Second descriptor loop . 25
4.2.2.2.1 Service list descriptor . 25
4.2.3 Descriptors of the Service Description Table (SDT) . 25
4.2.3.1 Announcement support descriptor . 25
4.2.3.2 CA identifier descriptor . 26
4.2.3.3 Component descriptor . 26
4.2.3.4 Country availability descriptor . 26
4.2.3.5 Data_broadcast_descriptor . 26
4.2.3.6 Linkage descriptor . 26
4.2.3.7 Mosaic descriptor . 27
4.2.3.8 Multilingual service name descriptor . 27
4.2.3.9 NVOD reference descriptor . 27
4.2.3.10 Service descriptor . 27
4.2.3.11 Service availability descriptor . 27
4.2.3.11.1 Network Implementation Considerations . 28
4.2.3.11.2 IRD implementation considerations . 28
4.2.3.12 Service relocated descriptor . 29
4.2.3.13 Telephone descriptor . 29
4.2.3.14 Time shifted service descriptor . 29
4.2.4 Descriptors of the Event Information Table (EIT) . 30
4.2.4.1 CA identifier descriptor . 30
4.2.4.2 Component descriptor . 30
4.2.4.3 Content descriptor . 31
4.2.4.4 Data_broadcast_descriptor . 31
4.2.4.5 Extended event descriptor . 31
4.2.4.6 Linkage descriptor . 31
4.2.4.7 Multilingual component descriptor . 32
4.2.4.8 Parental rating descriptor . 32
4.2.4.9 PDC descriptor . 32
4.2.4.10 Short event descriptor . 32
4.2.4.11 Telephone descriptor . 32
4.2.4.12 Time shifted event descriptor . 32
4.2.5 Descriptors of the Time Offset Table (TOT) . 33
4.2.5.1 Local time offset descriptor. 33
4.2.6 Descriptors of the Program Map Table (PMT) . 33
4.2.6.1 AC-3 descriptor . 34
4.2.6.2 Adaptation field data descriptor . 34
4.2.6.3 Ancillary data descriptor . 34
4.2.6.4 Data broadcast id descriptor . 34
4.2.6.5 Mosaic descriptor . 34
4.2.6.6 Service move descriptor . 34
4.2.6.7 Stream identifier descriptor . 35
4.2.6.8 Subtitling descriptor . 35
4.2.6.9 Teletext descriptor . 35
4.2.6.10 VBI data descriptor . 35
4.2.6.11 VBI teletext descriptor . 35
4.2.7 Other descriptors . 36
4.2.7.1 Private data specifier descriptor . 36
4.2.7.2 Stuffing descriptor . 36
4.2.7.3 Data_broadcast_descriptor . 36
4.2.7.4 Transport_stream_descriptor . 36
4.2.7.5 Target_region and target_region_name descriptors . 37
4.2.7.5.1 General Description . 37
4.2.7.5.2 Region selection by the IRD . 37
4.2.8 ISO/IEC 13818-1 descriptors . 38
4.2.9 Unknown descriptors . 38
4.3 Program Specific Information (PSI) and DVB SI operational interaction states . 38
4.4 Minimum repetition rates . 39
4.4.1 Satellite and cable delivery systems . 39
4.4.2 Terrestrial delivery systems . 40
ETSI
5 ETSI TS 101 211 V1.12.1 (2013-12)
4.5 Terrestrial systems . 40
4.5.1 The use of alternative frequencies for multiplexes . 41
4.5.2 Regional or local services . 42
4.5.3 Hand-over . 43
4.5.3.1 General description of the requirements . 43
4.5.3.2 Hand-over by means of the frequency_list_descriptor . 44
4.5.3.3 The occurrence of tuning failures . 45
4.5.3.4 Hand-over methods with a reduced risk of tuning failures . 46
4.5.3.4.1 Local SI insertion . 47
4.5.3.4.2 Cell identification . 47
4.5.3.4.3 Performance enhancement with GPS data . 47
4.5.3.4.4 Two front-end solution . 47
4.5.3.5 Performance considerations . 48
4.5.3.6 Receiver guidelines for hand-over . 48
4.5.3.6.1 Hand-over by means of the frequency_list_descriptor . 48
4.5.3.6.2 Hand-over by means of cell identification . 49
4.5.3.6.3 Hand-over by means of cell description and GPS position . 49
4.5.3.6.4 Hand-over with two-front-end solutions . 50
4.5.3.7 Additional linkage modes . 50
4.5.3.8 Additional remarks . 51
4.6 Text string formatting . 51
4.6.1 Use of control codes in names . 51
4.6.2 Use of control codes in text . 52
4.6.3 Use of UTF-8 . 52
5 Applications . 52
5.1 NVOD services . 52
5.2 Mosaic services . 54
5.2.1 General considerations . 54
5.2.2 Relationship between mosaic service and SI/PSI Tables . 55
5.3 Transitions at broadcast delivery media boundaries . 56
5.3.1 Seamless transitions . 56
5.3.2 Non-seamless transitions without re-multiplexing. 57
5.3.3 Transitions with re-multiplexing . 57
5.4 Announcements . 58
6 Storage media . 58
6.1 Program Association Table (PAT) . 58
6.2 Program Map Table (PMT) . 58
6.3 SI tables (NIT, SDT, EIT, BAT, RST, TDT, TOT) . 58
6.4 Selection Information Table (SIT) . 59
6.5 Discontinuity Information Table (DIT) . 59
Annex A (informative): Bibliography . 60
History . 61

ETSI
6 ETSI TS 101 211 V1.12.1 (2013-12)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Specification (TS) has been produced by Joint Technical Committee (JTC) Broadcast of the European
Broadcasting Union (EBU), Comité Européen de Normalisation ELECtrotechnique (CENELEC) and the European
Telecommunications Standards Institute (ETSI).
NOTE: The EBU/ETSI JTC Broadcast was established in 1990 to co-ordinate the drafting of standards in the
specific field of broadcasting and related fields. Since 1995 the JTC Broadcast became a tripartite body
by including in the Memorandum of Understanding also CENELEC, which is responsible for the
standardization of radio and television receivers. The EBU is a professional association of broadcasting
organizations whose work includes the co-ordination of its members' activities in the technical, legal,
programme-making and programme-exchange domains. The EBU has active members in about
60 countries in the European broadcasting area; its headquarters is in Geneva.
European Broadcasting Union
CH-1218 GRAND SACONNEX (Geneva)
Switzerland
Tel: +41 22 717 21 11
Fax: +41 22 717 24 81
The Digital Video Broadcasting Project (DVB) is an industry-led consortium of broadcasters, manufacturers, network
operators, software developers, regulatory bodies, content owners and others committed to designing global standards
for the delivery of digital television and data services. DVB fosters market driven solutions that meet the needs and
economic circumstances of broadcast industry stakeholders and consumers. DVB standards cover all aspects of digital
television from transmission through interfacing, conditional access and interactivity for digital video, audio and data.
The consortium came together in 1993 to provide global standardization, interoperability and future proof
specifications.
ETSI
7 ETSI TS 101 211 V1.12.1 (2013-12)
1 Scope
The present document provides implementation guidelines for the use and implementation of the DVB Service
Information (SI) coding in a DVB digital TV environment including satellite- cable- and terrestrial networks.
The guidelines are intended to be highly recommended rules for the usage of the DVB SI syntax specified in
EN 300 468 [i.1]. As such, they facilitate the efficient and reliable implementation of basic user-interaction functions in
Integrated Receiver-Decoders (IRD).
The rules apply to broadcasters, network operators as well as manufacturers.
The rules are specified in the form of constraints on the DVB SI streams or in terms of intended interpretation by IRDs.
The specification of these functions in no way prohibits IRD manufacturers from including additional features, and
should not be interpreted as stipulating any form of upper limit to the performance.
The guidelines do not cover features related to user-interface details or advanced Electronic Program Guides (EPG).
Such issues are left to the marketplace.
NOTE: It is highly recommended that the IRD should be designed to allow for future compatible extensions to
the DVB SI syntax. All the fields "reserved" (for ISO), "reserved_future_use" (for ETSI), and "user
defined" in the EN 300 468 [i.1] should be ignored by IRDs designed not to make use of them. The
"reserved" and "reserved_future_use" fields may be specified in the future by the respective bodies,
whereas the "user defined" fields will not be standardized.
The present document uses the terminology defined in EN 300 468 [i.1] and should be read in conjunction with that EN.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
Not applicable.
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI EN 300 468: "Digital Video Broadcasting (DVB); Specification for Service Information (SI)
in DVB systems".
[i.2] ISO/IEC 13818-1: "Information technology - Generic coding of moving pictures and associated
audio information: Systems".
[i.3] ETSI EN 300 472: "Digital Video Broadcasting (DVB); Specification for conveying ITU-R
System B Teletext in DVB bitstreams".
ETSI
8 ETSI TS 101 211 V1.12.1 (2013-12)
[i.4] ETSI TS 101 162: "Digital Video Broadcasting (DVB); Allocation of identifiers and codes for
Digital Video Broadcasting (DVB) systems".
[i.5] ETSI EN 301 192: "Digital Video Broadcasting (DVB); DVB specification for data broadcasting".
[i.6] ETSI TR 101 202: "Digital Video Broadcasting (DVB); Implementation guidelines for Data
Broadcasting".
[i.7] Recommendation ITU-R BS.1196-1: "Audio coding for digital terrestrial television broadcasting".
NOTE 1: Available at http://www.itu.int/rec/R-REC-BS.1196-1-200104-S/en.
NOTE 2: Annex 2 "Digital Audio Compression (AC-3) Standard (ATSC Standard)", contains additional
information on the AC-3 audio encoding algorithm and decoding requirements, relevant to the present
document. Appendix 1 to Annex 2 of this Recommendation should be disregarded as it is not applicable
to the present document.
[i.8] ETSI EN 300 744: "Digital Video Broadcasting (DVB); Framing structure, channel coding and
modulation for digital terrestrial television".
[i.9] ETSI TR 101 154: "Digital Video Broadcasting (DVB); Implementation guidelines for the use of
MPEG-2 Systems, Video and Audio in satellite, cable and terrestrial broadcasting applications".
[i.10] ETSI EN 301 775: "Digital Video Broadcasting (DVB); Specification for the carriage of Vertical
Blanking Information (VBI) data in DVB bitstreams".
[i.11] ETSI EN 301 210: "Digital Video Broadcasting (DVB); Framing structure, channel coding and
modulation for Digital Satellite News Gathering (DSNG) and other contribution applications by
satellite".
[i.12] ETSI EN 300 231: "Television systems; Specification of the domestic video Programme Delivery
Control system (PDC)".
[i.13] ISO/IEC 13818-3: "Information technology - Generic coding of moving pictures and associated
audio information - Part 3: Audio".
[i.14] ISO/IEC 11172-3: "Information technology - Coding of moving pictures and associated audio for
digital storage media at up to about 1,5 Mbit/s - Part 3: Audio".
[i.15] ETSI EN 300 743: "Digital Video Broadcasting (DVB); Subtitling systems".
[i.16] ETSI EN 300 401: "Radio Broadcasting Systems; Digital Audio Broadcasting (DAB) to mobile,
portable and fixed receivers".
[i.17] ETSI TS 102 006: "Digital Video Broadcasting (DVB); Specification for System Software Update
in DVB Systems".
[i.18] ISO/IEC 13818-2: "Information technology - Generic coding of moving pictures and associated
audio information: Video".
[i.19] ETSI TS 102 201: "Digital Video Broadcasting (DVB); Interfaces for DVB Integrated Receiver
Decoder (DVB-IRD)".
[i.20] ETSI ETS 300 801: "Digital Video Broadcasting (DVB); Interaction channel through Public
Switched Telecommunications Network (PSTN) / Integrated Services Digital Networks (ISDN)".
[i.21] ETSI EN 301 193: "Digital Video Broadcasting (DVB); Interaction channel through the Digital
Enhanced Cordless Telecommunications (DECT)".
[i.22] ISO 639-2: "Codes for the representation of names of languages - Part 2: Alpha-3 code".
[i.23] ETSI TS 103 205: "Digital Video Broadcasting (DVB); Extensions to the CI Plus Specification".
[i.24] ETSI TS 102 034: "Digital Video Broadcasting (DVB); Transport of MPEG-2 TS Based DVB
Services over IP Based Networks".
ETSI
9 ETSI TS 101 211 V1.12.1 (2013-12)
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
AC-3: refers to the coding of audio using the Dolby AC-3 method (Recommendation ITU-R BS.1196-1 [i.7])
NOTE: The Service Information requirements for AC-3 streams carried in DVB systems is described in annex E
of EN 300 468 [i.1]. The carriage of AC-3 elementary streams as private data within MPEG systems is
described in annex C of TR 101 154 [i.9].
bouquet: collection of services marketed as a single entity
broadcaster (SERVICE Provider): organization which assembles a sequence of events or data streams to be delivered
to the viewer; the delivery can be based upon a schedule
cell: geographical area that is covered with DVB signals delivering one or more particular transport or other DVB
streams throughout the area by means of one or more transmitters
NOTE: The cell may in addition contain repeaters. Two neighbouring cells may be intersecting, or fully
overlapping. The cell_id that is used to uniquely identify a cell is unique within each original_network_id.
For hand-over purposes it is more convenient if the transport streams associated with the cell cover
exactly the same area, or only one transport stream per cell is used.
component (ELEMENTARY Stream): one or more entities which together make up an event
EXAMPLE: Video, audio, Teletext.
Conditional Access (CA) system: system to control subscriber access to services, data streams and events
EXAMPLE: Videoguard, Eurocrypt.
delivery system: physical medium by which one or more DVB transport streams are transmitted
EXAMPLE: Satellite system, wide-band coaxial cable, fibre optics, terrestrial channel of one emitting point.
DVB transport stream: MPEG-2 transport stream [i.2] containing the mandatory DVB-SI signalling as defined in
EN 300 468 [i.1]
NOTE: It is recommended that the present document should be followed in addition. It defines additional
requirements for the signalling to help improve the quality of experience for viewers.
emitting site: collection of transmitters and/or repeaters gathered in one location
event: grouping of elementary broadcast data streams with a defined start time and duration belonging to a common
service
EXAMPLE: First half of a football match, News Flash, first part of an entertainment show.
MPEG-2: Refers to the standard ISO/IEC 13818.
NOTE: Systems coding is defined in part 1 [i.2].
Video coding is defined in part 2 [i.18].
Audio coding is defined in part 3 [i.13].
Multi Frequency Network (MFN) mode: geographical area is operated in MFN mode if the modulation parameters
and frequencies used to broadcast a DVB transport stream differ from one emitting site to another
ETSI
10 ETSI TS 101 211 V1.12.1 (2013-12)
network: managed and navigable collection of DVB transport streams transmitted on one or more delivery systems
generally based on the same physical medium
NOTE: It is possible to operate both, first and second generation delivery systems in the same network (e.g.
DVB-T and DVB-T2)
NOTE: A network is identified by its network_id. It might be composed of one or more emitting sites.
repeater: special type of transmitter which receives a terrestrial DVB signal and re-transmits it unchanged
NOTE: Hence it does not support changing of the cell_id
section: syntactic structure used for mapping all service information into ISO/IEC 13818-1 [i.2]
NOTE: Transport Stream (TS) packets.
service: grouping (usually defined by a PMT) of one or more data streams which are offered as a whole to the user
Service Information (SI): describes the delivery system, and the content and scheduling/timing of services and events
NOTE: It includes MPEG-2 Program Specific Information (PSI) with DVB-defined extensions.
Single Frequency Network (SFN) mode: geographical area is operated in SFN mode if all emitting sites are
synchronized and use the same frequency and modulation parameters to broadcast the same DVB transport stream
subcell: geographical area that is part of the cell's coverage area and that is covered with DVB signals by means of a
transposer
NOTE: In conjunction with the cell_id the cell_id_extension is used to uniquely identify a subcell.
sub-table: comprised of a number of sections with the same value of table_id, table_id_extension and version_number
NOTE: The table_id_extension field is equivalent to the fourth and fifth byte of a section when the
section_syntax_indicator is set to a value of "1".
table: comprised of a number of sections with the same value of table_id
transmitter: equipment that emits a modulated DVB stream
Transport Stream (TS): data structure defined in ISO/IEC 13818-1 [i.2]
NOTE: It is the basis of the DVB standards.
transposer: special type of repeater which receives a terrestrial DVB signal and re-transmits it on a different frequency
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AC-3 dolby AC-3 audio coding
ASCII American Standard Code for Information Interchange
ATSC Advanced Television Systems Committee of the USA
BAT Bouquet Association Table
CA Conditional Access
CR Carriage Return character
DAB Digital Audio Broadcasting
DIT Discontinuity Information Table
DSNG Digital Satellite News Gathering
DVB Digital Video Broadcasting
DVB-H DVB-Handheld
DVB-SH DVB-Satellite to Handheld devices
DVD Digital Versatile Disc
EIT Event Information Table
EITp/f Event Information Table, present and following
EPG Electronic Program Guide
ETSI
11 ETSI TS 101 211 V1.12.1 (2013-12)
ES Elementary Stream
GPS Global Positioning System
HD High Definition (Video)
IRD Integrated Receiver-Decoder
LF Line Feed Character
MFN Multi-Frequency Network
MJD Modified Julian Date
MPEG Moving Pictures Expert Group
NIT Network Information Table
NVOD Near Video On Demand
PAT Program Association Table
PDC Programme Delivery Control
PID Packet IDentifier
PIL Programme Identification Label
PMT Program Map Table
PSI Program Specific Information
QAM Quadrature Amplitude Modulation
QPSK Quadrature Phase Shift Keying
RST Running Status Table
SD Standard Definition (Video)
SDT Service Description Table
SFN Single Frequency Network
SHY Soft HYphen
SI Service Information
SIT Selection Information Table
SMATV Satellite Master Antenna TeleVision
ST Stuffing Table
TDT Time and Date Table
TOT Time Offset Table
TPS Transmission Parameter Signalling
TS Transport Stream
TSDT Transport Stream Description Table
UCS Universal Character Set
UTC Universal Time Coordinated
UTF UCS Transformation Format
VBI Vertical Blanking Interval
VPS Video Programme System
WSS Wide Screen Signalling
4 Rules of operation
This clause contains some recommendations on the usage of the Digital Video Broadcasting (DVB) Service
Information (SI) syntax.
ETSI
12 ETSI TS 101 211 V1.12.1 (2013-12)
4.1 Service Information (SI) table information

Figure 1: SI table information
4.1.1 Network Information Table (NIT) information
The Network Information Table (NIT) provides a grouping of Transport Streams (TSs) and the relevant tuning
information. The NIT could be used during set-up procedures of the IRD and the relevant tuning information may be
stored in non-volatile memory. The NIT also could be used to signal changes of tuning information. The following rules
apply to the NIT:
a) transmission of the NIT is mandatory for the actual delivery system;
b) the NIT describing the actual delivery system is valid if and only if it contains applicable delivery system
descriptors for the actual delivery system. At some transitions of broadcast delivery system boundaries, the
NIT carried in a TS is allowed to be invalid, and to describe an earlier network in the broadcast chain. In this
case, a different mechanism has to be selected by the IRD to obtain the relevant tuning information for the
actual delivery system. More information is provided in clause 5.3;
c) if a valid NIT for the actual delivery system is present in the SI bit stream then it shall list all TSs of the actual
delivery system;
d) the SI stream shall have at least 8 TS packets per 10 s carrying NIT data or NULL packets. This rule simplifies
the replacement of the NIT at broadcast delivery system boundaries. With the simple replacement mechanism,
local frequency control is possible with relatively low cost equipment.
The SI uses two labels related to the concept of a delivery system, namely the network_id and the original_network_id.
The latter is intended to support the unique identification of a service,
...