SIST-TP ETR 154 E3:2005

SLOVENSKI STANDARD
01-november-2005
Digitalna videoradiodifuzija (DVB) – Smernice za uvajanje uporabe sistemov MPEG
-2, videa in avdia v satelitskih, kabelskih in prizemnih radiodifuzijskih aplikacijah
Digital Video Broadcasting (DVB); Implementation guidelines for the use of MPEG-2
Systems, Video and Audio in satellite, cable and terrestrial broadcasting applications
Ta slovenski standard je istoveten z: ETR 154 Edition 3
ICS:
33.170 Televizijska in radijska Television and radio
difuzija broadcasting
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

ETSI ETR 154
TECHNICAL September 1997
REPORT Third Edition
Source: EBU/CENELEC/ETSI JTC Reference: RTR/JTC-00DVB-38
ICS: 33.020
Key words: DVB, broadcasting, digital, video, MPEG, TV
European Broadcasting Union Union Européenne de Radio-Télévision
Digital Video Broadcasting (DVB);
Implementation guidelines for the use of
MPEG-2 Systems, Video and Audio in satellite, cable
and terrestrial broadcasting applications
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: secretariat@etsi.fr
Tel.: +33 4 92 94 42 00 - Fax: +33 4 93 65 47 16
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 1997.
© European Broadcasting Union 1997.
All rights reserved.
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ETR 154: September 1997
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.

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ETR 154: September 1997
Contents
Foreword .5
Introduction.6
1 Scope .8
2 References.8
3 Definitions and abbreviations .9
3.1 Definitions .9
3.2 Abbreviations .9
4 Systems layer.10
4.1 Broadcast bitstreams and Baseline IRDs .10
4.1.1 Introduction (ISO/IEC 13818-1, section 0) .10
4.1.2 Packetized Elementary Stream (PES) (ISO/IEC 13818-1, section 0.4) .10
4.1.3 TS system target decoder (ISO/IEC 13818-1, section 2.4.2).11
4.1.4 Transport packet layer (ISO/IEC 13818-1, section 2.4.3.2) .11
4.1.4.1 Null packets .11
4.1.4.2 Transport packet header .11
4.1.4.2.1 transport_error_indicator .11
4.1.4.2.2 transport_priority.11
4.1.4.2.3 transport_scrambling_control .11
4.1.4.2.4 Packet IDentifier (PID) values for
Service Information (SI) Tables .11
4.1.5 Adaptation field (ISO/IEC 13818-1, section 2.4.3.4) .11
4.1.5.1 Random_access_indicator .11
4.1.5.2 elementary_stream_priority_indicator.11
4.1.5.3 Program Clock Reference (PCR) .12
4.1.5.4 Other fields .12
4.1.6 Packetized Elementary Stream (PES) Packet (ISO/IEC 13818-1, section
2.4.3.6) .12
4.1.6.1 stream_id.12
4.1.6.2 PES_scrambling_control .12
4.1.6.3 PES_priority.12
4.1.6.4 copyright and original_or_copy.12
4.1.6.5 Trick mode fields .13
4.1.6.6 additional_copy_info .13
4.1.6.7 Optional fields.13
4.1.6.8 PES_extension_field.13
4.1.7 Program Specific Information (PSI) (ISO/IEC 13818-1, section 2.4.4) .13
4.1.8 Program and elementary stream descriptors (ISO/IEC 13818-1, section
2.6) .14
4.1.8.1 video_stream_descriptor and audio_stream_descriptor .14
4.1.8.2 hierarchy_descriptor .14
4.1.8.3 registration_descriptor .14
4.1.8.4 data_stream_alignment_descriptor .14
4.1.8.5 target_background_grid_descriptor.14
4.1.8.6 video_window_descriptor .14
4.1.8.7 Conditional Access CA_descriptor .15
4.1.8.8 ISO_639_Language_descriptor.15
4.1.8.9 system_clock_descriptor .15
4.1.8.10 multiplex_buffer_utilization_descriptor .15
4.1.8.11 copyright_descriptor .15
4.1.8.12 maximum_bitrate_descriptor .15
4.1.8.13 private_data_indicator_descriptor.15
4.1.8.14 STD_descriptor.15

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ETR 154: September 1997
4.1.8.15 IBP_descriptor. 15
4.1.8.16 smoothing_buffer_descriptor . 15
4.1.9 Compatibility with ISO/IEC 11172-1 (ISO/IEC 13818-1, section 2.8) . 16
4.1.10 Storage Media Interoperability. 16
4.2 Bitstreams from storage applications and IRDs with digital interfaces . 16
4.2.1 Partial TSs . 16
4.2.2 Decoding of Trick Play data (ISO/IEC 13818-1, section 2.4.3.7) . 16
5 Video. 17
5.1 25 Hz SDTV IRDs and Bitstreams . 17
5.1.1 Profile and level . 17
5.1.2 Frame rate . 17
5.1.3 Aspect ratio. 18
5.1.4 Luminance resolution. 19
5.1.5 Chromaticity Parameters . 20
5.1.6 Chrominance . 21
5.1.7 Video sequence header. 21
5.2 25 Hz HDTV IRDs and Bitstreams. 21
5.2.1 Profile and level . 21
5.2.2 Frame rate . 21
5.2.3 Aspect ratio. 22
5.2.4 Luminance resolution. 22
5.2.5 Chromaticity Parameters . 22
5.2.6 Chrominance . 23
5.2.7 Video sequence header. 23
5.2.8 Backwards Compatibility. 23
5.3 30 Hz SDTV IRDs and Bitstreams . 23
5.3.1 Profile and level . 23
5.3.2 Frame rate . 23
5.3.3 Aspect ratio. 24
5.3.4 Luminance resolution. 25
5.3.5 Chromaticity Parameters . 26
5.3.6 Chrominance . 26
5.3.7 Video sequence header. 26
5.4 30 Hz HDTV IRDs and Bitstreams. 26
5.4.1 Profile and level . 26
5.4.2 Frame rate . 26
5.4.3 Aspect ratio. 27
5.4.4 Luminance resolution. 27
5.4.5 Chromaticity Parameters . 28
5.4.6 Chrominance . 28
5.4.7 Video sequence header. 28
5.4.8 Backwards Compatibility. 28
6 Audio. 28
6.1 Audio mode . 29
6.2 Compression layer .29
6.3 Bit rate. 29
6.4 Sampling frequency.30
6.5 Emphasis . 30
6.6 Cyclic redundancy code . 30
Annex A (informative): Examples of full screen luminance resolutions for SDTV and HDTV. 31
History. 32

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ETR 154: September 1997
Foreword
This ETSI Technical Report (ETR) has been produced under the authority of the Joint Technical
Committee (JTC) of the European Broadcasting Union (EBU), Comité Européen de Normalisation
ELECtrotechnique (CENELEC) and the European Telecommunications Standards Institute (ETSI).
This ETR is based on the DVB document A001 revision 2, dated July 1997, and it may be converted into
an ETS after market feedback. For this purpose, the wording of an ETS rather than an ETR is used.
ETRs are informative documents resulting from ETSI studies which are not appropriate for European
Telecommunication Standard (ETS) or Interim European Telecommunication Standard (I-ETS) status. An
ETR may be used to publish material which is either of an informative nature, relating to the use or the
application of ETSs or I-ETSs, or which is immature and not yet suitable for formal adoption as an ETS or
an I-ETS.
NOTE: The EBU/ETSI JTC was established in 1990 to co-ordinate the drafting of standards in
the specific field of broadcasting and related fields. Since 1995 the JTC 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
Case Postale 67
CH-1218 GRAND SACONNEX (Geneva)
Switzerland
Tel: +41 22 717 21 11
Fax: +41 22 717 24 81
Digital Video Broadcasting (DVB) Project
Founded in September 1993, the DVB Project is a market-led consortium of public and private sector
organizations in the television industry. Its aim is to establish the framework for the introduction of
MPEG-2 based digital television services. Now comprising over 200 organizations from more than
25 countries around the world, DVB fosters market-led systems, which meet the real needs, and
economic circumstances, of the consumer electronics and the broadcast industry.

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ETR 154: September 1997
Introduction
This ETR presents guidelines covering coding and decoding using the MPEG-2 system layer, video
coding and audio coding as defined in ISO/IEC 13818-1 [1], ISO/IEC 13818-2 [2] and ISO/IEC 13818-3 [3]
respectively.
The guidelines presented in this ETR for the Integrated Receiver-Decoder (IRD) are intended to represent
a minimum functionality that all IRDs of a particular class are required to either meet or exceed. It is
necessary to specify the minimum IRD functionality for basic parameters, if broadcasters are not to be
prevented from ever using certain features. For example, if a significant population of IRDs were produced
that supported only the Simple Profile, broadcasters would never be able to transmit Main Profile bit-
streams.
IRDs are classified in three dimensions as:
- "25 Hz" or "30 Hz", depending on whether the nominal video frame rates based on 25 Hz or
30000/1001 Hz (approximately 29,97 Hz) are supported. It is expected that 25 Hz IRDs will be used
in those countries where the existing analogue TV transmissions use 25 Hz frame rate and 30 Hz
IRDs will be used in countries where the analogue TV transmissions use 30000/1001 Hz frame
rate. There are also likely to be "dual-standard" IRDs which have the capabilities of both 25 Hz and
30 Hz IRDs.
- "SDTV" or "HDTV", depending on whether or not they are limited to decoding pictures of
conventional TV resolution. The capabilities of an SDTV IRD are a sub-set of those of an HDTV
IRD.
- "with digital interface" or "Baseline", depending on whether or not they are intended for use with a
digital bitstream storage device such as a digital VCR. The capabilities of a Baseline IRD are a sub-
set of those of an IRD with digital interface.
To give a complete definition of an IRD, all three dimensions need to be specified, e.g. 25 Hz SDTV
Baseline IRD.
It should be noted that in DVB systems the source picture format, encoded picture format and display
picture format do not need to be identical. For example, HDTV source material may be broadcast as an
SDTV bitstream after down-conversion to SDTV resolution and encoding within the constraints of Main
Profile at Main Level. The IRD receiving the bitstream may then up-convert the decoded picture for display
at HDTV resolution. With suitable down-conversion and up-conversion, the quality of the resultant HDTV
picture may be close to that of the original HDTV source.
Another notable feature of the DVB system is that a single Transport Stream (TS) may contain
programme material intended for more than one type of IRD. A typical example of this is likely to be the
simulcasting of SDTV and HDTV video material. In this case an SDTV IRD will decode and display SDTV
pictures whilst an HDTV IRD will decode and display HDTV pictures from the same TS.
Where a feature described in this ETR is mandatory, the word "shall" is used and the text is in italic; all
other features are optional. The functionality is specified in the form of constraints on MPEG-2 systems,
video and audio which the IRDs are required to decode correctly.
The specification of these baseline features 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, such as the IRD's up-sampling filter, which affect the quality of the
displayed picture rather than whether the IRD is able to decode pictures at all. Such issues are left to the
marketplace.
The guidelines presented for IRDs observe the following principles:
- wherever practical, IRDs should be designed to allow for future compatible extensions to the bit-
stream syntax;
- all "reserved" and "private" bits in MPEG-2 systems, video and audio should be ignored by IRDs not
designed to make use of them.
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ETR 154: September 1997
The rules of operation for the encoders are features and constraints which the encoding system should
adhere to in order to ensure that the transmissions can be correctly decoded. These constraints may be
mandatory or optional. Where a feature or constraint is mandatory, the word "shall" is used and the text is
italic; all other features are optional.
Clauses 4 to 6 provide the guidelines for the Digital Video Broadcasting (DVB) systems layer, video and
audio respectively. For information, some of the key features are summarized below, but clauses 4 to 6
should be consulted for all definitions:
Systems:
- MPEG-2 TS is used;
- Service Information (SI) is based on MPEG-2 program-specific information;
- scrambling is as defined in ETR 289 [5];
- conditional access uses the MPEG-2 Conditional Access CA_descriptor;
- Partial TSs are used for digital VCR applications.
Video:
- MPEG-2 Main Profile at Main Level is used for SDTV;
- MPEG-2 Main Profile at High Level is used for HDTV;
- the 25 Hz SDTV IRD supports 25 Hz frame rate;
- the 25 Hz HDTV IRD supports frame rates of 25 Hz or 50 Hz;
- the 30 Hz SDTV IRD supports frame rates of 24000/1001, 24, 30000/1001 and 30 Hz;
- the 30 Hz HDTV IRD supports frame rates of 24000/1001, 24, 30000/1001, 30, 60000/1001 and
60 Hz;
- SDTV pictures may have either 4:3, 16:9 or 2.21:1 aspect ratio; IRDs support 4:3 and 16:9 and
optionally 2.21:1 aspect ratio;
- HDTV pictures have 16:9 or 2.21:1aspect ratio; IRDs support 16:9 and optionally 2.21:1 aspect
ratio;
- IRDs support the use of pan vectors to allow a 4:3 monitor to give a full-screen display of a 16:9
coded picture of SDTV resolution.
Audio:
- MPEG-2 Layer I and Layer II is supported by the IRD;
- the use of Layer II is recommended for the encoded bit-stream;
- IRDs support single channel, dual channel, joint stereo, stereo and the extraction of at least a
stereo pair from MPEG-2 compatible multi-channel audio;
- sampling rates of 32 kHz, 44,1 kHz and 48 kHz are supported by IRDs;
- the encoded bit-stream does not use emphasis.

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ETR 154: September 1997
1 Scope
This ETSI Technical Report (ETR) provides implementation guidelines for the use of MPEG-2 audio-visual
coding in satellite, cable and terrestrial broadcasting distribution systems. Both Standard Definition
Television (SDTV) and High Definition Television (HDTV) are covered. Guidelines for devices equipped
with a digital interface intended for digital VCR applications are also given in this ETR. It does not cover
applications such as contribution services which are likely to be the subject of subsequent "Guidelines"
documents.
The rules of operation for the encoders are features and constraints which the encoding system should
adhere to in order to ensure that the transmissions can be correctly decoded. These constraints may be
mandatory, recommended or optional.
2 References
This ETR incorporates by dated and undated reference, provisions from other publications. These
references are cited at the appropriate places in the text and the publications are listed hereafter. For
dated references, subsequent amendments to or revisions of any of these publications apply to this ETR
only when incorporated in it by amendment or revision. For undated references the latest edition of the
publication referred to applies.
[1] ISO/IEC 13818-1 (1996): "Coding of moving pictures and associated audio -
Part 1: Systems".
[2] ISO/IEC 13818-2 (1996): "Coding of moving pictures and associated audio -
Part 2: Video".
[3] ISO/IEC 13818-3 rev1 (1997): "Coding of moving pictures and associated audio
- Part 3: Audio".
[4] ISO/IEC 13818-9 (1996): "Coding of moving pictures and associated audio -
Part 9: Extension for Real-Time-Interface for systems decoders ".
[5] ETR 289: "Digital Video Broadcasting (DVB); Common Scrambling (CS) system
description".
[6] prEN 300 468: "Digital Video Broadcasting (DVB); Specification for Service
Information (SI) in DVB systems".
[7] ETR 211: "Digital Video Broadcasting (DVB); Guidelines for the usage of
Service Information (SI) in DVB systems".
[8] ISO/IEC 11172-1: "Information Technology - Coding of moving pictures and
associated audio for digital storage media up to about 1,5 Mbit/s - Part 1:
Systems".
[9] ITU-T Recommendation J.17 (1988): "Pre-emphasis used on sound-programme
circuits".
[10] IEC CD - 100C/1883: Parts 1 and 4.
[11] EBU Recommendation R.68: "Alignment level in digital audio production
equipment and in digital audio recorders".

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3 Definitions and abbreviations
3.1 Definitions
For the purposes of this ETR, the following definitions apply:
25hz SDTV IRD: An IRD which is capable of decoding and displaying pictures based on a nominal video
frame rate of 25 Hz from MPEG-2 Main Profile, Main Level bitstreams as specified in this ETR.
25hz SDTV bitstream: A bitstream which contains only Main Profile, Main Level video at 25 Hz frame rate
as specified in this ETR.
25hz HDTV IRD: An IRD that is capable of decoding and displaying pictures based on a nominal video
frame rate of 25 Hz or 50 Hz from MPEG-2 Main Profile, High Level bitstreams as specified in this ETR, in
addition to providing the functionality of a 25 Hz SDTV IRD.
25hz HDTV bitstream: A bitstream which contains only Main Profile, High Level (or simpler) video at
25 Hz or 50 Hz frame rates as specified in this ETR.
30hz SDTV IRD: An IRD which is capable of decoding and displaying pictures based on a nominal video
frame rate of 24000/1001(approximately 23,98), 24, 30000/1001 (approximately 29,97) or 30 Hz from
MPEG-2 Main Profile at Main Level bitstreams as specified in this ETR.
30hz SDTV bitstream: A bitstream which contains only Main Profile, Main Level video at 24000/1001, 24,
30000/1001 or 30 Hz frame rate as specified in this ETR.
30hz HDTV IRD: An IRD that is capable of decoding and displaying pictures based on nominal video
frame rates of 24000/1001, 24, 30000/1001, 30, 60/1001 or 60 Hz from MPEG-2 Main Profile, High Level
bitstreams as specified in this ETR, in addition to providing the functionality of a 30 Hz SDTV IRD.
30hz HDTV bitstream: A bitstream which contains only Main Profile, High Level (or simpler) video at
24000/1001, 24, 30000/1001, 30, 60/1001 or 60 Hz frame rates as specified in this ETR.
baseline IRD: An IRD which provides the minimum functionality to decode transmitted bitstreams as
recommended in this ETR. It is not required to have the ability to decode Partial Transport Streams (TSs)
as may be received from a digital interface connected to digital bitstream storage device such as a digital
VCR.
IRD with digital interface: An IRD which has the ability to decode Partial Transport Streams (TSs)
received from a digital interface connected to digital bitstream storage device such as a digital VCR as
specified in this ETR, in addition to providing the functionality of a Baseline IRD.
pan vector: Horizontal offset in video frame centre position.
Partial Transport Stream (TS): Bitstream derived from an MPEG-2 TS by removing those TS Packets
that are not relevant to one particular selected programme, or a number of selected programmes.
3.2 Abbreviations
For the purposes of this ETR, the following abbreviations apply:
CA Conditional Access
DVB Digital Video Broadcasting
ES Elementary Stream
ESCR Elementary Stream Clock Reference
I-Frame Intra-coded Frame
IRD Integrated Receiver-Decoder
HDTV High Definition TeleVision
MPEG Moving Pictures Experts Group
NIT Network Information Table
PAT Program Association Table
PCR Program Clock Reference
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PES Packetized Elementary Stream
PID Packet IDentifier
PMT Program Map Table
PSI Program Specific Information
PSW Pan and Scan Window
SI Service Information
SDTV Standard Definition Television
STD System Target Decoder
TS Transport Stream
TSDT Transport Stream Description Table
T-STD Transport Stream System Target Decoder
VCR Video Cassette Recorder
4 Systems layer
This clause describes the guidelines for encoding the systems layer of MPEG-2 in DVB broadcast
bit-streams, and for decoding this layer in the IRD. The source bitstream may be transmitted via a
satellite, cable or terrestrial channel, or via a digital interface. Subclause 4.1 applies to the encoding of all
source bitstreams and their decoding by a Baseline IRD. Subclause 4.2 gives specific information relating
to bitstreams transmitted via a digital interface intended for VCR applications and decoding by IRDs
equipped with such an interface.
4.1 Broadcast bitstreams and Baseline IRDs
The multiplexing of baseband signals and associated data conforms to ISO/IEC 13818-1 [1]. Some of the
parameters and fields are not used in the DVB System and these restrictions are described below. To
allow full compliance to ISO/IEC 13818-1 [1] and upward compatibility with future enhanced versions, a
DVB IRD shall be able to skip over data structures which are currently "reserved", or which correspond to
functions not implemented by the IRD. As an example of this capability, a descriptor tag not yet defined
within the DVB System shall be interpreted as a no-action tag, its length field correctly decoded and
subsequent data skipped.
For the same reason, IRD design should be made under the assumption that any legal structure as
permitted by ISO/IEC 13818-1 [1] may occur in the broadcast stream even if presently reserved or
unused. Therefore the following is assumed:
- private data shall only be acted upon by decoders which are so enabled;
- filling out the bit-stream shall be carried out using the normal stuffing mechanism. Reserved fields
shall not be used for this purpose. Data of reserved fields shall be set to 0xFF.
The headings below in this clause are based on ISO/IEC 13818-1 [1]. The numbers in brackets after the
headings are the relevant chapter and section headings of ISO/IEC 13818-1 [1].
4.1.1 Introduction (ISO/IEC 13818-1, section 0)
MPEG-2 systems specify two types of multiplexed data stream: the Transport Stream (TS) and the
program stream.
Encoding: The transmitted multiplex shall use the TS.
Decoding: All Baseline IRDs shall be able to demultiplex the MPEG-2 TS. Demultiplexing of program
streams (as described in sections 0.2 and 0.3 of [1]) is optional.
4.1.2 Packetized Elementary Stream (PES) (ISO/IEC 13818-1, section 0.4)
Encoding: The creation of a physical Packetized Elementary Stream (PES) by an encoder is not
required. ESCR fields and ES rate fields need not be coded.
Decoding: ESCR fields and ES rate fields need not be decoded.

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4.1.3 TS system target decoder (ISO/IEC 13818-1, section 2.4.2)
Encoding: The system clock frequency shall conform to the tolerance specified in section 2.4.2.1 of
ISO/IEC 13818-1 [1]. It is recommended that the tolerance is within 5 parts per million.
Decoding: The IRD shall operate over the full tolerance range of the system clock frequency specified in
section 2.4.2.1 of ISO/IEC 13818-1 [1].
4.1.4 Transport packet layer (ISO/IEC 13818-1, section 2.4.3.2)
4.1.4.1 Null packets
Encoding: The encoding of null packets (those with PID value 0x1FFF) shall be as specified in
ISO/IEC 13818-1 [1].
4.1.4.2 Transport packet header
4.1.4.2.1 transport_error_indicator
Encoding: It is recommended that any error detecting devices in a transmission path should set the
transport_error_indicator bit when uncorrectable errors are detected.
Decoding: The transport_error_indicator flag is set in the transmitted stream it is recommended that
the IRD should then invoke a suitable concealment or error recovery mechanism.
4.1.4.2.2 transport_priority
Decoding: The transport_priority bit has no meaning to the IRD, and may be ignored.
4.1.4.2.3 transport_scrambling_control
Encoding: The transport_scrambling_control bits shall be set according to table 1, in accordance with
ETR 289 [5].
Table 1: Coding of transport_scrambling_control bits
Value Description
00 no scrambling of TS packet payload
01 reserved for future DVB use
10 TS packet scrambled with Even key
11 TS packet scrambled with Odd key
Decoding: These bits shall be read by the IRD, and the IRD shall respond in accordance with table 1.
4.1.4.2.4 Packet IDentifier (PID) values for Service Information (SI) Tables
Encoding: The assignment of PID values for SI data is given in EN 300 468 [6].
4.1.5 Adaptation field (ISO/IEC 13818-1, section 2.4.3.4)
4.1.5.1 Random_access_indicator
Encoding: It is recommended that the random_access_indicator bit is set whenever a random access
point occurs in video streams (i.e. video sequence header immediately followed by an I-frame).
4.1.5.2 elementary_stream_priority_indicator
Decoding: The elementary_stream_priority_indicator bit may be ignored by the IRD.

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ETR 154: September 1997
4.1.5.3 Program Clock Reference (PCR)
Encoding: The time interval between two consecutive PCR values of the same program shall not
exceed 100 milliseconds as specified in section 2.7.3 of ISO/IEC 13818-1 [1]. It is recommended that this
interval should be no greater than 40 milliseconds.
Decoding: The IRD shall operate correctly with PCRs for a program arriving at intervals not exceeding
100 milliseconds.
4.1.5.4 Other fields
This subclause covers the following fields:
- original_program_clock_reference_base;
- original_program_clock_reference_extension;
- splice_countdown;
- private_data_byte;
- adaptation_field_extension (including fields within).
Encoding: These fields are optional in a DVB bit-stream. The flags that indicate the presence or
absence of each of these fields shall be set appropriately.
Decoding: IRDs shall be able to accept bit-streams which contain these fields. IRDs may ignore the data
within the fields.
4.1.6 Packetized Elementary Stream (PES) Packet (ISO/IEC 13818-1, section 2.4.3.6)
4.1.6.1 stream_id
Encoding: Within a program, no two elementary streams shall have the same stream_id.
4.1.6.2 PES_scrambling_control
Encoding: The PES_scrambling_control bits shall be set according to table 2, in accordance with
ETR 289 [5].
Table 2: Coding of PES_scrambling_control bits
Value Description
00 no scrambling of PES packet payload
01 reserved for future DVB use
10 PES packet scrambled with Even key
11 PES packet scrambled with Odd key
Decoding: The PES_scrambling_control bits shall be read by the IRD, and the IRD shall respond in
accordance with table 2.
4.1.6.3 PES_priority
Decoding: The PES_priority bit may be ignored by the IRD.
4.1.6.4 copyright and original_or_copy
Encoding: The copyright and original_or_copy bits may be set as appropriate.
Decoding: The IRD need not interpret these bits. The setting of these bits shall not be altered in any
digital output from the IRD.
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ETR 154: September 1997
4.1.6.5 Trick mode fields
This subclause covers the following fields:
- trick_mode_control;
- field_id;
- intra_slice_refresh;
- frequency_truncation;
- field_rep_cntrl.
Encoding: These trick mode fields shall not be transmitted in a broadcast bit-stream. Bit-streams for
other applications (e.g. for non-broadcast interactive services, storage applications, etc.) may use these
fields.
Decoding: The IRD may skip over any data which is flagged as being in a trick mode, if it does not
support decoding of trick modes. If the IRD has a digital interface intended for digital VCR applications, it
is recommended that it supports decoding of trick modes as indicated in subclause 2.2.
4.1.6.6 additional_copy_info
Encoding: This field may used as appropriate.
Decoding: The IRD need not interpret this field. The coding of the field shall not be altered in any digital
output from the IRD.
4.1.6.7 Optional fields
This subclause covers the following fields:
- ESCR;
- ESCR_extension;
- ES_rate;
- previous_PES_packet_CRC;
- PES_private_data;
- pack_header();
- program_packet_sequence_counter;
- MPEG1_MPEG2_identifier;
- original_stuff_length;
- P-STD_buffer_scale;
- P-STD_buffer_size.
Encoding: These fields are optional in a DVB bit-stream. The flags that indicate the presence or
absence of each of these fields shall be set appropriately.
Decoding: The IRD shall be able to accept bit-streams which contain these fields. The IRD may ignore
the data within the fields.
4.1.6.8 PES_extension_field
The PES_extension_field data field is currently "reserved".
Encoding: This extension field shall not be coded unless specified in the future by MPEG.
Decoding: The IRD shall be able to accept bit-streams which contain this field. The IRD may ignore the
data within the field.
4.1.7 Program Specific Information (PSI) (ISO/IEC 13818-1, section 2.4.4)
The data formats for the Transport Stream Description Table (TSDT) and Network Information Table
(NIT) in DVB bit-streams are given in EN 300 468 [6]. This ETS also defines additional tables for service
information which use Program Specific Information (PSI) private_section structure defined in
ISO/IEC 13818-1 [1].
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It is recommended that the Transport Stream Description Table (TSDT), Program Association Table
(PAT) and Program Map Table (PMT) are repeated with a maximum time interval of 100 milliseconds
between repetitions.
4.1.8 Program and elementary stream descriptors (ISO/IEC 13818-1, section 2.6)
4.1.8.1 video_stream_descriptor and audio_stream_descriptor
Encoding: The video_stream_descriptor shall be used to indicate video streams containing still picture
data, otherwise these descriptors may be used when appropriate. If profile_and_level_indication is not
present, then the video bit-stream shall comply with the constraints of Main Profile at Main Level.
If the audio_stream_descriptor is not present, then the audio bit-stream shall not use sampling
frequencies of 16 kHz, 22,05 kHz or 24 kHz, and all audio frames in the stream shall have the same bit
rate.
Decoding: The IRD may use these descriptors when present to determine if it is able to decode the
streams. If neither video_stream_descriptor nor hierarchy_descriptor is present for a video bit-stream,
the IRD may assume that it complies with Main Profile at Main Level constraints.
4.1.8.2 hierarchy_descriptor
Encoding: The hierarchy_descriptor shall be used if, and only if, video or audio is coded as more than
one hierarchical layer.
Decoding: If the descriptor is present and indicates that the bit-stream is a base layer video stream, then
the IRD shall be capable of selecting that bit if a video_stream_descriptor defines it as Main Profile at
Main Level or less.
4.1.8.3 registration_descriptor
Encoding: The registration_descriptor may be used when appropriate.
Decoding: The IRD need not make use of this descriptor.
4.1.8.4 data_stream_alignment_descriptor
Encoding: The data_stream_alignment_descriptor may be used when appropriate.
Decoding: The IRD need not make use of this descriptor.
4.1.8.5 target_background_grid_descriptor
Encoding: The target_background_grid_descriptor may be used when appropriate.
Decoding: If this descriptor is absent, a default grid of 720 × 576 pixels shall be assumed by a 25 Hz
IRD, a default grid of 720 × 480 pixels shall be assumed by a 30 Hz IRD. The IRD shall read this
descriptor, when present, to override this default. The display of correctly windowed video on background
grids other than 720 × 576 pixels is optional for a 25 Hz SDTV IRD, the display of correctly windowed
video on background grids other than 720 × 480 pixels is optional for a 30 Hz SDTV IRD.
4.1.8.6 video_window_descriptor
Encoding: The video_window_descriptor may be used when appropriate, to indicate the required
position of the video window on the screen.
Decoding: The IRD shall read this descriptor, when present, and position the video window accordingly.

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4.1.8.7 Conditional Access CA_descriptor
Encoding: The CA_descriptor shall be encoded as defined in ETR 289 [5].
Decoding: The IRD shall interpret this descriptor as defined in ETR 289 [5].
4.1.8.8 ISO_639_Language_descriptor
Encoding: The ISO_639_Language_descriptor shall be present if more than one audio (or video)
stream with different languages are present within a program. It is optional otherwise.
Decoding: The IRD shall use the data from this descriptor to assist the selection of appropriate audio (or
video) stream of program, if more than one stream is available.
4.1.8.9 system_clock_descriptor
Encoding: It is recommended that the system_clock_descriptor is included in the program_info part of
the Program Map Table for each program.
Decoding: The IRD need not make use of this descriptor.
4.1.8.10 multiplex_buffer_utilization_descriptor
Encoding: The multiplex_buffer_utilization_descriptor may be used when appropriate.
Decoding: The IRD need not make use of this descriptor.
4.1.8.11 copyright_descriptor
Encoding: The copyright_descriptor may be used when appropriate.
Decoding: The IRD need not make use of this descriptor.
4.1.8.12 maximum_bitrate_descriptor
Encoding: The maximum_bitrate_descriptor may be used when appropriate.
Decoding: The IRD need not make use of this descriptor.
4.1.8.13 private_data_indicator_descriptor
Encoding: The private_data_indicator_descriptor may be used when appropriate.
Decoding: The IRD need not make use of this descriptor.
4.1.8.14 STD_descriptor
Encoding: The STD_descriptor shall be used as specified in ISO/IEC 13818-1 [1].
Decoding: The IRD need not make use of this descriptor.
4.1.8.15 IBP_descriptor
Encoding: The IBP_descriptor may be used when appropriate.
Decoding: The IRD need not make use of this descriptor.
4.1.8.16 smoothing_buffer_descriptor
Encoding: It is recommended that the smoothing_buffer_descriptor is included in the Program Map
Table in the extended program information.

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Decoding: The IRD need not make use of this descriptor, but the information may be of assistance to
digital VCRs.
Additional descriptors to those defined in ISO/IEC 13818-1 [1] are defined in EN 300 468 [6], and
guidelines for their use are provided in ETR 211 [7]: "Guidelines on implementation and usage of Service
Information".
4.1.9 Compatibility with ISO/IEC 11172-1 (ISO/IEC 13818-1, section 2.8)
Decoding: Compatibility with ISO/IEC 11172-1 [8] (MPEG-1 Systems) is optional.
4.1.10 Storage Media Interoperability
It is recommended that the total bitrate of the set of service components, associated PMT and PCR
packets anticipated to be recorded by a consumer, should not exceed 9 000 000 bit/s.
It is recommended that the parameters sb_size and sb_leak_rate in the smoothing_buffer_descriptor
remain constant for the duration of an event. The value of the sb_leak_rate should be the peak attained
during the event. The short_smoothing_buffer_descriptor is defined in EN 300 468 [6] and guidelines for
its use are provided in ETR 211 [7].
4.2 Bitstreams from storage applications and IRDs with digital interfaces
This subclause covers both the treatment of Partial TSs which result from external program selection and
Trick Play information received from a storage device. MPEG-2 PSI and DVB SI tables for use specifically
in storage applications are defined in EN 300 468 [6].
4.2.1 Partial TSs
Partial TSs for transfer on a digital interface, e.g. for digital VCR applications, have been defined in
IEC CD-100C/1883 [10]. A Partial TS may be created by selection of TS Packets from one or more
program(s), including PSI Packets.
Encoding The Partial TS shall be fully MPEG compliant with reference to MPEG-2 "Extension for Real-
Time-Interface for systems decoders" (ISO 13818-9) [4].
Decoding Devices equipped with a digital interface intended for digital VCR applications shall accept
the bursty character of a Partial TS with gaps of variable length between the TS Packets.
4.2.2 Decoding of Trick Play data (ISO/IEC 13818-1, section 2.4.3.7)
Encoding Trick mode operation shall be signalled by use of the DSM_trick_mode flag in the header of
the video Packetized Elementary Stream (PES) packets. During trick mode playback the storage device
shall construct a bitstream which is syntactically and semantically correct, except as outlined in the note
below.
Decoding It is recommended that devices decode the DSM_trick_mode_flag and the eight bit trick
mode field. Devices which decode the trick mode data shall follow the normative requirements detailed in
I
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