SIST EN 303 560 V1.1.1:2018
(Main)Digital Video Broadcasting (DVB) - TTML subtitling systems
Digital Video Broadcasting (DVB) - TTML subtitling systems
The present document specifies the transport of TTML [2] subtitle streams in DVB MPEG-2 transport streams,
based on the MPEG-2 system described in ISO/IEC 13818-1 [1]. TTML is an XML-based representation. The present
document provides syntax for delivery of TTML subtitle streams over MPEG-2 transport stream, and is based on
EBU-TT-D [3] compatible with the IMSC1 [4] Text Profile of W3C TTML [2].
Digitalna videoradiodifuzija (DVB) - Sistemi TTML za podnaslove
Ta dokument določa prenos pretokov podnaslovov TTML [2] prek pretokov prenosov DVB MPEG-2 na podlagi sistema MPEG-2, opisanega v standardu ISO/IEC 13818-1 [1]. TTML je predstavitev na podlagi XML-ja. Ta dokument določa skladnjo za dostavljanje pretokov podnaslovov TTML prek pretoka prenosov MPEG-2 ter temelji na formatu EBU-TT-D [3], združljivem z besedilnim profilom IMSC1 [4] jezika W3C TTML [2].
General Information
Buy Standard
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 303 560 V1.1.1:2018
01-september-2018
Digitalna videoradiodifuzija (DVB) - Sistemi TTML za podnaslove
Digital Video Broadcasting (DVB) - TTML subtitling systems
Ta slovenski standard je istoveten z: ETSI EN 303 560 V1.1.1 (2018-05)
ICS:
33.170 Televizijska in radijska Television and radio
difuzija broadcasting
SIST EN 303 560 V1.1.1:2018 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 303 560 V1.1.1:2018
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SIST EN 303 560 V1.1.1:2018
ETSI EN 303 560 V1.1.1 (2018-05)
EUROPEAN STANDARD
Digital Video Broadcasting (DVB);
TTML subtitling systems
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SIST EN 303 560 V1.1.1:2018
2 ETSI EN 303 560 V1.1.1 (2018-05)
Reference
DEN/JTC-DVB-375
Keywords
broadcast, digital, DVB, subtitle, TV
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
The present document can be downloaded from:
http://www.etsi.org/standards-search
The present document may be made available in electronic versions and/or in print. The content of any electronic and/or
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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
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If you find errors in the present document, please send your comment to one of the following services:
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Copyright Notification
No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying
and microfilm except as authorized by written permission of ETSI.
The content of the PDF version shall not be modified without the written authorization of ETSI.
The copyright and the foregoing restriction extend to reproduction in all media.
© ETSI 2018.
© European Broadcasting Union 2018.
All rights reserved.
TM TM TM
DECT , PLUGTESTS , UMTS and the ETSI logo are trademarks of ETSI registered for the benefit of its Members.
TM TM
3GPP and LTE are trademarks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
oneM2M logo is protected for the benefit of its Members.
®
GSM and the GSM logo are trademarks registered and owned by the GSM Association.
ETSI
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SIST EN 303 560 V1.1.1:2018
3 ETSI EN 303 560 V1.1.1 (2018-05)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 6
Introduction . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definitions and abbreviations . 9
3.1 Definitions . 9
3.2 Abbreviations . 10
4 Default DVB TTML subtitle conformance point . 11
4.1 Introduction . 11
4.2 Document Constraints . 11
4.2.1 General . 11
4.2.2 Regions . 12
4.2.3 Document complexity . 12
4.2.4 Document encoding . 12
4.2.5 Namespaces . 12
4.2.6 Guidance for document authors and content providers (informative) . 12
4.2.6.1 Overview . 12
4.2.6.2 Font mapping for generic font family names . 12
4.2.6.3 Default text colour. 13
4.2.6.4 Requirement for support of optional features . 13
4.2.6.5 Specifying active area . 13
5 Delivery . 13
5.1 IP delivery . 13
5.2 Broadcast TS delivery . 13
5.2.1 PSI/SI signalling . 13
5.2.1.1 TTML subtitling descriptor . 13
5.2.1.2 Example TTML profile signalling . 17
5.2.1.2.1 Signalling conformance only to the default conformance point . 17
5.2.1.2.2 Signalling conformance to only EBU-TT-D . 17
5.2.1.2.3 Signalling conformance with EBU-TT-D and the default conformance point . 17
5.2.1.2.4 Signalling conformance to only IMSC1 Text Profile . 18
5.2.1.3 Presentation properties in qualifier field . 18
5.2.1.4 Component descriptors for TTML subtitles . 19
5.2.2 TS packetization . 19
5.2.2.1 PES packet format and carriage in the TS . 19
5.2.2.2 PES packet payload format for TTML subtitling . 20
5.2.2.2.1 General PES payload field syntax and segment types . 20
5.2.2.2.2 Occurrences of segments in one PES packet . 21
5.2.2.2.3 Uncompressed TTML document subtitle segment . 21
5.2.2.2.4 gzip compressed TTML document subtitle segment . 21
5.2.3 TTML segmentation . 21
5.2.3.1 General . 21
5.2.3.2 Concept of ISDs . 22
5.2.3.3 Active Period of a TTML segment . 22
5.2.3.4 TTML documents segmentation rules . 22
5.2.3.5 Subtitle stream in the absence of subtit les . 22
5.2.3.6 Continuation of a subtitle across adjacent segments . 22
5.2.3.7 Untimed elements in TTML segments . 23
5.2.3.8 Examples of TTML segmentation . 23
ETSI
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4 ETSI EN 303 560 V1.1.1 (2018-05)
5.2.4 Synchronization . 23
5.2.4.1 Relationship between MPEG system clock and TTML timeline . 23
5.2.4.2 Failure of TTML segment reception . 24
5.2.4.3 Synchronization examples . 24
5.2.5 Acquisition time . 27
5.3 Font download . 27
5.3.1 Introduction. 27
5.3.2 Font delivery signalling mechanism . 28
5.3.2.1 Overview . 28
5.3.2.2 Linkage descriptor with linkage type 0x20 . 29
5.3.2.2.1 Introduction . 29
5.3.2.2.2 Linkage descriptor with linkage type 0x20 structure . 29
5.3.2.2.3 Linkage descriptor with linkage type 0x20 location, occurrence and prioritization . 30
5.3.2.3 Downloadable Font Information Table (DFIT) . 30
5.3.2.3.1 DFIT structure . 30
5.3.2.3.2 font_info_type in the loop of the DFIS . 32
5.3.3 IP download fonts . 33
5.3.4 Broadcast download fonts . 33
5.3.5 Downloaded font file, font name and font-id association . 33
6 IRD requirements . . 34
6.1 General support . 34
6.2 Forward compatibility . 34
6.3 Support of PSI/SI signalling and subtitle service selection . 34
6.3.1 PSI/SI signalling . 34
6.3.2 Determining which subtitle services can be rendered . 34
6.3.3 Subtitle service selection . 34
6.4 Font support in IRDs . 35
6.4.1 Supported fonts and font family name mapping . 35
6.4.2 Downloadable font retrieval . 35
6.4.3 Font selection for subtitle rendering . 36
6.5 Rendering requirements . 36
6.5.1 Playback free-running when A/V sync lost temporarily . 36
6.5.2 Behaviour during trick play . 36
6.5.3 Subtitle composition with HDR video . 36
6.5.4 Cropping and scaling of video . 37
6.6 Additional TTML processor requirements . 37
Annex A (informative): Change History . 38
History . 39
ETSI
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SIST EN 303 560 V1.1.1:2018
5 ETSI EN 303 560 V1.1.1 (2018-05)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables 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 (https://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.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This European Standard (EN) 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
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SIST EN 303 560 V1.1.1:2018
6 ETSI EN 303 560 V1.1.1 (2018-05)
National transposition dates
Date of adoption of this EN: 30 April 2018
Date of latest announcement of this EN (doa): 31 July 2018
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 31 January 2019
Date of withdrawal of any conflicting National Standard (dow): 31 January 2019
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
Today's broadcast content can be distributed in many forms and via many different paths. Whilst broadcast services
traditionally relied on bitmap-based subtitles because of processing simplicity, advanced processing and text rendering
have made text-based approaches feasible. These offer more flexibility and better options to improve the user
experience. TTML (Timed Text Markup Language) is established as a common solution for IP-based platforms, but
multiple profiles exist.
In Europe, the EBU Group 'Subtitles in XML' published the EBU-TT-D TTML profile [20] which was adopted by the
®
DVB DASH specification as defined in ETSI TS 103 285 [6] and by HbbTV as defined in ETSI TS 102 79 [5]. The
W3C later published the IMSC1 TTML profiles [4], which were adopted by ATSC.
There are only minor differences between EBU-TT-D [3], [20] and IMSC1 Text Profile.
The present specification builds on the existing widespread device support for EBU-TT-D [20], in particular through
®
support for HbbTV , to enable the distribution of TTML subtitles together with audio/video content via broadcast.
Clause 4 specifies TTML subtitle constraints for a default conformance point, to be supported by both EBU-TT-D [3],
[20] and IMSC1 Text Profile compatible processors.
Clause 5 specifies subtitle delivery, including PSI/SI signalling, TS packetisation, TTML segmentation and
synchronization requirements.
Finally clause 6 specifies IRD requirements.
ETSI
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SIST EN 303 560 V1.1.1:2018
7 ETSI EN 303 560 V1.1.1 (2018-05)
1 Scope
The present document specifies the transport of TTML [2] subtitle streams in DVB MPEG-2 transport streams,
based on the MPEG-2 system described in ISO/IEC 13818-1 [1]. TTML is an XML-based representation. The present
document provides syntax for delivery of TTML subtitle streams over MPEG-2 transport stream, and is based on
EBU-TT-D [3] compatible with the IMSC1 [4] Text Profile of W3C TTML [2].
2 References
2.1 Normative 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
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://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.
The following referenced documents are necessary for the application of the present document.
[1] ISO/IEC 13818-1: "Information technology -- Generic coding of moving pictures and associated
audio information -- Part 1: Systems".
[2] W3C Recommendation (TTML): "Timed Text Markup Language 1 (TTML1) (Second Edition)".
NOTE: Available at http://www.w3.org/TR/2013/REC-ttml1-20130924/.
[3] EBU Tech 3380 "EBU-TT-D Subtitling Distribution Format", version 1.0.1.
NOTE: Available at https://tech.ebu.ch/publications/tech3380.
[4] W3C Recommendation (IMSC1): "TTML Profiles for Internet Media Subtitles and Captions 1.0.1
(IMSC1)".
NOTE: Available at http://www.w3.org/TR/ttml-imsc1.0.1/.
[5] ETSI TS 102 796: "Hybrid Broadcast Broadband TV".
[6] ETSI TS 103 285: "Digital Video Broadcasting (DVB); MPEG-DASH Profile for Transport of
ISO BMFF Based DVB Services over IP Based Networks".
[7] DVB BlueBook A038: "Digital Video Broadcasting (DVB); Specification for Service Information
(SI) in DVB systems".
NOTE: Available at http://www.dvb.org/resources/public/standards/a038_dvb_spec_december_2017.pdf.
[8] ISO 639-2: "Codes for the representation of names of languages -- Part 2: Alpha-3 code".
[9] ISO/IEC 8859-1: "Information technology -- 8-bit single-byte coded graphic character sets --
Part 1: Latin alphabet No. 1".
[10] W3C Working Group Note: "TTML Media Type Definition and Profile Registry".
NOTE: Available at http://www.w3.org/TR/ttml-profile-registry/.
[11] ETSI EN 301 192: "Digital Video Broadcasting (DVB); DVB specification for data broadcasting".
[12] ETSI TS 102 809: "Digital Video Broadcasting (DVB); Signalling and carriage of interactive
applications and services in hybrid broadcast/broadband environments".
ETSI
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SIST EN 303 560 V1.1.1:2018
8 ETSI EN 303 560 V1.1.1 (2018-05)
[13] ETSI TS 102 851: "Digital Video Broadcasting (DVB); Uniform Resource Identifiers (URI) for
DVB Systems".
[14] IETF RFC 1952: "GZIP file format specification version 4.3".
[15] DVB BlueBook A126: "Digital Video Broadcasting (DVB); Allocation of identifiers and codes for
Digital Video Broadcasting (DVB) systems".
NOTE: Available at https://www.dvb.org/resources/public/standards/a126_allocation_identifiers.pdf.
[16] W3C Recommendation (XML): "Extensible Markup Language (XML) 1.0 (Fifth Edition)".
NOTE: Available at https://www.w3.org/TR/2008/REC-xml-20081126/.
[17] EBU Tech 3381: "Carriage of EBU-TT-D in ISOBMFF", version 1.0.
NOTE: Available at https://tech.ebu.ch/publications/tech3381.
[18] W3C Recommendation 13 December 2012 (WOFF): "Web Open Font Format (WOFF) 1.0".
NOTE: Available at http://www.w3.org/TR/2012/REC-WOFF-20121213/.
[19] ISO/IEC 14496-22:2015: "Information technology -- Coding of audio-visual objects --
Part 22: Open Font Format".
[20] EBU Tech 3380: "EBU-TT-D Subtitling Distribution Format", version 1.0.
NOTE: Available at https://tech.ebu.ch/publications/tech3380.
[21] IETF RFC 3986: "Uniform Resource Identifier (URI): Generic Syntax".
2.2 Informative 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
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
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] W3C Recommendation (WCAG): "Web Content Accessibility Guidelines (WCAG) 2.0".
NOTE: Available at https://www.w3.org/TR/2008/REC-WCAG20-20081211/.
[i.2] W3C Candidate Recommendation (CSS): "CSS Fonts Module Level 3: Font matching algorithm".
NOTE: Available at https://www.w3.org/TR/css-fonts-3/#font-matching-algorithm.
[i.3] IEC 61966-2-1:1999: "Multimedia systems and equipment - Colour measurement and
management - Part 2-1: Colour management - Default RGB colour space - sRGB".
ETSI
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SIST EN 303 560 V1.1.1:2018
9 ETSI EN 303 560 V1.1.1 (2018-05)
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
Intermediate Synchronic Document (ISD): temporally bounded (possibly empty) subset of TTML content during
which no elements change state between active and inactive
NOTE: A TTML document can conceptually be considered as a contiguous sequence of ISDs.
maximum period of activation (MPA): maximum duration a single TTML segment can be active, referred to as T
MPA
Packet IDentifier (PID): transport stream packet identifier
NOTE: See ISO/IEC 13818-1 [1].
PES packet: See ISO/IEC 13818-1 [1].
Presentation Time Stamp (PTS): See ISO/IEC 13818-1 [1].
reserved_zero_future_use: when used in the clause defining the coded bit stream, indicates that the value may be used
in the future for ETSI defined extensions
NOTE: All "reserved_zero_future_use" bits are set to "0".
subtitle segment: basic syntactical element of a subtitle stream
NOTE: The present document is structured to allow other types of subtitle segments to be defined in the future. In
this version of the specification, all subtitle segments are TTML segments.
subtitle service properties: properties defined by TTML subtitling descriptor which include but are not limited to
language, purpose, TTS_suitability, font usage, and qualifier
subtitle service: service that provides subtitling for an MPEG program (DVB service) with a set of subtitle service
properties
subtitle service qualifier variants: set
...
ETSI EN 303 560 V1.1.1 (2018-05)
EUROPEAN STANDARD
Digital Video Broadcasting (DVB);
TTML subtitling systems
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2 ETSI EN 303 560 V1.1.1 (2018-05)
Reference
DEN/JTC-DVB-375
Keywords
broadcast, digital, DVB, subtitle, TV
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
The present document can be downloaded from:
http://www.etsi.org/standards-search
The present document may be made available in electronic versions and/or in print. The content of any electronic and/or
print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any
existing or perceived difference in contents between such versions and/or in print, the only prevailing document is the
print of the Portable Document Format (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
https://portal.etsi.org/TB/ETSIDeliverableStatus.aspx
If you find errors in the present document, please send your comment to one of the following services:
https://portal.etsi.org/People/CommiteeSupportStaff.aspx
Copyright Notification
No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying
and microfilm except as authorized by written permission of ETSI.
The content of the PDF version shall not be modified without the written authorization of ETSI.
The copyright and the foregoing restriction extend to reproduction in all media.
© ETSI 2018.
© European Broadcasting Union 2018.
All rights reserved.
TM TM TM
DECT , PLUGTESTS , UMTS and the ETSI logo are trademarks of ETSI registered for the benefit of its Members.
TM TM
3GPP and LTE are trademarks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
oneM2M logo is protected for the benefit of its Members.
®
GSM and the GSM logo are trademarks registered and owned by the GSM Association.
ETSI
---------------------- Page: 2 ----------------------
3 ETSI EN 303 560 V1.1.1 (2018-05)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 6
Introduction . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definitions and abbreviations . 9
3.1 Definitions . 9
3.2 Abbreviations . 10
4 Default DVB TTML subtitle conformance point . 11
4.1 Introduction . 11
4.2 Document Constraints . 11
4.2.1 General . 11
4.2.2 Regions . 12
4.2.3 Document complexity . 12
4.2.4 Document encoding . 12
4.2.5 Namespaces . 12
4.2.6 Guidance for document authors and content providers (informative) . 12
4.2.6.1 Overview . 12
4.2.6.2 Font mapping for generic font family names . 12
4.2.6.3 Default text colour. 13
4.2.6.4 Requirement for support of optional features . 13
4.2.6.5 Specifying active area . 13
5 Delivery . 13
5.1 IP delivery . 13
5.2 Broadcast TS delivery . 13
5.2.1 PSI/SI signalling . 13
5.2.1.1 TTML subtitling descriptor . 13
5.2.1.2 Example TTML profile signalling . 17
5.2.1.2.1 Signalling conformance only to the default conformance point . 17
5.2.1.2.2 Signalling conformance to only EBU-TT-D . 17
5.2.1.2.3 Signalling conformance with EBU-TT-D and the default conformance point . 17
5.2.1.2.4 Signalling conformance to only IMSC1 Text Profile . 18
5.2.1.3 Presentation properties in qualifier field . 18
5.2.1.4 Component descriptors for TTML subtitles . 19
5.2.2 TS packetization . 19
5.2.2.1 PES packet format and carriage in the TS . 19
5.2.2.2 PES packet payload format for TTML subtitling . 20
5.2.2.2.1 General PES payload field syntax and segment types . 20
5.2.2.2.2 Occurrences of segments in one PES packet . 21
5.2.2.2.3 Uncompressed TTML document subtitle segment . 21
5.2.2.2.4 gzip compressed TTML document subtitle segment . 21
5.2.3 TTML segmentation . 21
5.2.3.1 General . 21
5.2.3.2 Concept of ISDs . 22
5.2.3.3 Active Period of a TTML segment . 22
5.2.3.4 TTML documents segmentation rules . 22
5.2.3.5 Subtitle stream in the absence of subtit les . 22
5.2.3.6 Continuation of a subtitle across adjacent segments . 22
5.2.3.7 Untimed elements in TTML segments . 23
5.2.3.8 Examples of TTML segmentation . 23
ETSI
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4 ETSI EN 303 560 V1.1.1 (2018-05)
5.2.4 Synchronization . 23
5.2.4.1 Relationship between MPEG system clock and TTML timeline . 23
5.2.4.2 Failure of TTML segment reception . 24
5.2.4.3 Synchronization examples . 24
5.2.5 Acquisition time . 27
5.3 Font download . 27
5.3.1 Introduction. 27
5.3.2 Font delivery signalling mechanism . 28
5.3.2.1 Overview . 28
5.3.2.2 Linkage descriptor with linkage type 0x20 . 29
5.3.2.2.1 Introduction . 29
5.3.2.2.2 Linkage descriptor with linkage type 0x20 structure . 29
5.3.2.2.3 Linkage descriptor with linkage type 0x20 location, occurrence and prioritization . 30
5.3.2.3 Downloadable Font Information Table (DFIT) . 30
5.3.2.3.1 DFIT structure . 30
5.3.2.3.2 font_info_type in the loop of the DFIS . 32
5.3.3 IP download fonts . 33
5.3.4 Broadcast download fonts . 33
5.3.5 Downloaded font file, font name and font-id association . 33
6 IRD requirements . . 34
6.1 General support . 34
6.2 Forward compatibility . 34
6.3 Support of PSI/SI signalling and subtitle service selection . 34
6.3.1 PSI/SI signalling . 34
6.3.2 Determining which subtitle services can be rendered . 34
6.3.3 Subtitle service selection . 34
6.4 Font support in IRDs . 35
6.4.1 Supported fonts and font family name mapping . 35
6.4.2 Downloadable font retrieval . 35
6.4.3 Font selection for subtitle rendering . 36
6.5 Rendering requirements . 36
6.5.1 Playback free-running when A/V sync lost temporarily . 36
6.5.2 Behaviour during trick play . 36
6.5.3 Subtitle composition with HDR video . 36
6.5.4 Cropping and scaling of video . 37
6.6 Additional TTML processor requirements . 37
Annex A (informative): Change History . 38
History . 39
ETSI
---------------------- Page: 4 ----------------------
5 ETSI EN 303 560 V1.1.1 (2018-05)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables 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 (https://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.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This European Standard (EN) 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
---------------------- Page: 5 ----------------------
6 ETSI EN 303 560 V1.1.1 (2018-05)
National transposition dates
Date of adoption of this EN: 30 April 2018
Date of latest announcement of this EN (doa): 31 July 2018
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 31 January 2019
Date of withdrawal of any conflicting National Standard (dow): 31 January 2019
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
Today's broadcast content can be distributed in many forms and via many different paths. Whilst broadcast services
traditionally relied on bitmap-based subtitles because of processing simplicity, advanced processing and text rendering
have made text-based approaches feasible. These offer more flexibility and better options to improve the user
experience. TTML (Timed Text Markup Language) is established as a common solution for IP-based platforms, but
multiple profiles exist.
In Europe, the EBU Group 'Subtitles in XML' published the EBU-TT-D TTML profile [20] which was adopted by the
®
DVB DASH specification as defined in ETSI TS 103 285 [6] and by HbbTV as defined in ETSI TS 102 79 [5]. The
W3C later published the IMSC1 TTML profiles [4], which were adopted by ATSC.
There are only minor differences between EBU-TT-D [3], [20] and IMSC1 Text Profile.
The present specification builds on the existing widespread device support for EBU-TT-D [20], in particular through
®
support for HbbTV , to enable the distribution of TTML subtitles together with audio/video content via broadcast.
Clause 4 specifies TTML subtitle constraints for a default conformance point, to be supported by both EBU-TT-D [3],
[20] and IMSC1 Text Profile compatible processors.
Clause 5 specifies subtitle delivery, including PSI/SI signalling, TS packetisation, TTML segmentation and
synchronization requirements.
Finally clause 6 specifies IRD requirements.
ETSI
---------------------- Page: 6 ----------------------
7 ETSI EN 303 560 V1.1.1 (2018-05)
1 Scope
The present document specifies the transport of TTML [2] subtitle streams in DVB MPEG-2 transport streams,
based on the MPEG-2 system described in ISO/IEC 13818-1 [1]. TTML is an XML-based representation. The present
document provides syntax for delivery of TTML subtitle streams over MPEG-2 transport stream, and is based on
EBU-TT-D [3] compatible with the IMSC1 [4] Text Profile of W3C TTML [2].
2 References
2.1 Normative 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
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://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.
The following referenced documents are necessary for the application of the present document.
[1] ISO/IEC 13818-1: "Information technology -- Generic coding of moving pictures and associated
audio information -- Part 1: Systems".
[2] W3C Recommendation (TTML): "Timed Text Markup Language 1 (TTML1) (Second Edition)".
NOTE: Available at http://www.w3.org/TR/2013/REC-ttml1-20130924/.
[3] EBU Tech 3380 "EBU-TT-D Subtitling Distribution Format", version 1.0.1.
NOTE: Available at https://tech.ebu.ch/publications/tech3380.
[4] W3C Recommendation (IMSC1): "TTML Profiles for Internet Media Subtitles and Captions 1.0.1
(IMSC1)".
NOTE: Available at http://www.w3.org/TR/ttml-imsc1.0.1/.
[5] ETSI TS 102 796: "Hybrid Broadcast Broadband TV".
[6] ETSI TS 103 285: "Digital Video Broadcasting (DVB); MPEG-DASH Profile for Transport of
ISO BMFF Based DVB Services over IP Based Networks".
[7] DVB BlueBook A038: "Digital Video Broadcasting (DVB); Specification for Service Information
(SI) in DVB systems".
NOTE: Available at http://www.dvb.org/resources/public/standards/a038_dvb_spec_december_2017.pdf.
[8] ISO 639-2: "Codes for the representation of names of languages -- Part 2: Alpha-3 code".
[9] ISO/IEC 8859-1: "Information technology -- 8-bit single-byte coded graphic character sets --
Part 1: Latin alphabet No. 1".
[10] W3C Working Group Note: "TTML Media Type Definition and Profile Registry".
NOTE: Available at http://www.w3.org/TR/ttml-profile-registry/.
[11] ETSI EN 301 192: "Digital Video Broadcasting (DVB); DVB specification for data broadcasting".
[12] ETSI TS 102 809: "Digital Video Broadcasting (DVB); Signalling and carriage of interactive
applications and services in hybrid broadcast/broadband environments".
ETSI
---------------------- Page: 7 ----------------------
8 ETSI EN 303 560 V1.1.1 (2018-05)
[13] ETSI TS 102 851: "Digital Video Broadcasting (DVB); Uniform Resource Identifiers (URI) for
DVB Systems".
[14] IETF RFC 1952: "GZIP file format specification version 4.3".
[15] DVB BlueBook A126: "Digital Video Broadcasting (DVB); Allocation of identifiers and codes for
Digital Video Broadcasting (DVB) systems".
NOTE: Available at https://www.dvb.org/resources/public/standards/a126_allocation_identifiers.pdf.
[16] W3C Recommendation (XML): "Extensible Markup Language (XML) 1.0 (Fifth Edition)".
NOTE: Available at https://www.w3.org/TR/2008/REC-xml-20081126/.
[17] EBU Tech 3381: "Carriage of EBU-TT-D in ISOBMFF", version 1.0.
NOTE: Available at https://tech.ebu.ch/publications/tech3381.
[18] W3C Recommendation 13 December 2012 (WOFF): "Web Open Font Format (WOFF) 1.0".
NOTE: Available at http://www.w3.org/TR/2012/REC-WOFF-20121213/.
[19] ISO/IEC 14496-22:2015: "Information technology -- Coding of audio-visual objects --
Part 22: Open Font Format".
[20] EBU Tech 3380: "EBU-TT-D Subtitling Distribution Format", version 1.0.
NOTE: Available at https://tech.ebu.ch/publications/tech3380.
[21] IETF RFC 3986: "Uniform Resource Identifier (URI): Generic Syntax".
2.2 Informative 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
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
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] W3C Recommendation (WCAG): "Web Content Accessibility Guidelines (WCAG) 2.0".
NOTE: Available at https://www.w3.org/TR/2008/REC-WCAG20-20081211/.
[i.2] W3C Candidate Recommendation (CSS): "CSS Fonts Module Level 3: Font matching algorithm".
NOTE: Available at https://www.w3.org/TR/css-fonts-3/#font-matching-algorithm.
[i.3] IEC 61966-2-1:1999: "Multimedia systems and equipment - Colour measurement and
management - Part 2-1: Colour management - Default RGB colour space - sRGB".
ETSI
---------------------- Page: 8 ----------------------
9 ETSI EN 303 560 V1.1.1 (2018-05)
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
Intermediate Synchronic Document (ISD): temporally bounded (possibly empty) subset of TTML content during
which no elements change state between active and inactive
NOTE: A TTML document can conceptually be considered as a contiguous sequence of ISDs.
maximum period of activation (MPA): maximum duration a single TTML segment can be active, referred to as T
MPA
Packet IDentifier (PID): transport stream packet identifier
NOTE: See ISO/IEC 13818-1 [1].
PES packet: See ISO/IEC 13818-1 [1].
Presentation Time Stamp (PTS): See ISO/IEC 13818-1 [1].
reserved_zero_future_use: when used in the clause defining the coded bit stream, indicates that the value may be used
in the future for ETSI defined extensions
NOTE: All "reserved_zero_future_use" bits are set to "0".
subtitle segment: basic syntactical element of a subtitle stream
NOTE: The present document is structured to allow other types of subtitle segments to be defined in the future. In
this version of the specification, all subtitle segments are TTML segments.
subtitle service properties: properties defined by TTML subtitling descriptor which include but are not limited to
language, purpose, TTS_suitability, font usage, and qualifier
subtitle service: service that provides subtitling for an MPEG program (DVB service) with a set of subtitle service
properties
subtitle service qualifier variants: set of subtitle services whose subtitle service properties are identical except for
the qualifier_present_flag and qualifier fields in the TTML subtitling descriptor
subtitle stream: stream of subtitle segments carried in transport stream packets identified by the same PID,
containing a single subtitle service
transport stream packet: See ISO/IEC 13818-1 [1].
transport stream: stream of transport stream packets carrying one or more MPEG programs
NOTE: See ISO/IEC 13818-1 [1].
TTML document chunk: self-contained and temporally bounded subset of a TTML document [2]
NOTE: Self-contained in this context means that the document chunk contains all elements to render this subset
except the actual fonts used.
TTML segment: subtitle segment whose payload is an XML serialization of a TTML document chunk, concretely
encoded as a well-formed XML 1.0 [16] document
ETSI
---------------------- Page: 9 ---------
...
Draft ETSI EN 303 560 V1.1.1 (2018-01)
EUROPEAN STANDARD
Digital Video Broadcasting (DVB);
TTML subtitling systems
---------------------- Page: 1 ----------------------
2 Draft ETSI EN 303 560 V1.1.1 (2018-01)
Reference
DEN/JTC-DVB-375
Keywords
broadcast, digital, DVB, subtitle, TV
ETSI
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All rights reserved.
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DECT , PLUGTESTS , UMTS and the ETSI logo are trademarks of ETSI registered for the benefit of its Members.
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3GPP and LTE™ are trademarks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
oneM2M logo is protected for the benefit of its Members.
GSM® and the GSM logo are trademarks registered and owned by the GSM Association.
ETSI
---------------------- Page: 2 ----------------------
3 Draft ETSI EN 303 560 V1.1.1 (2018-01)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 6
Introduction . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definitions and abbreviations . 9
3.1 Definitions . 9
3.2 Abbreviations . 10
4 Default DVB TTML subtitle conformance point . 11
4.1 Introduction . 11
4.2 Document Constraints . 11
4.2.1 General . 11
4.2.2 Regions . 12
4.2.3 Document complexity . 12
4.2.4 Document encoding . 12
4.2.5 Namespaces . 12
4.2.6 Guidance for document authors and content providers (informative) . 12
4.2.6.1 Overview . 12
4.2.6.2 Font mapping for generic font family names . 12
4.2.6.3 Default text colour. 13
4.2.6.4 Requirement for support of optional features . 13
4.2.6.5 Specifying active area . 13
5 Delivery . 13
5.1 IP delivery . 13
5.2 Broadcast TS delivery . 13
5.2.1 PSI/SI signalling . 13
5.2.1.1 TTML subtitling descriptor . 13
5.2.1.2 Example TTML profile signalling . 17
5.2.1.2.1 Signalling conformance only to the default conformance point . 17
5.2.1.2.2 Signalling conformance to only EBU-TT-D . 17
5.2.1.2.3 Signalling conformance with EBU-TT-D and the default conformance point . 17
5.2.1.2.4 Signalling conformance to only IMSC1 Text Profile . 18
5.2.1.3 Presentation properties in qualifier field . 18
5.2.1.4 Component descriptors for TTML subtitles . 19
5.2.2 TS packetization . 19
5.2.2.1 PES packet format and carriage in the TS . 19
5.2.2.2 PES packet payload format for TTML subtitling . 20
5.2.2.2.1 General PES payload field syntax and segment types . 20
5.2.2.2.2 Occurrences of segments in one PES packet . 21
5.2.2.2.3 Uncompressed TTML document subtitle segment . 21
5.2.2.2.4 gzip compressed TTML document subtitle segment . 21
5.2.3 TTML segmentation . 21
5.2.3.1 General . 21
5.2.3.2 Concept of ISDs . 22
5.2.3.3 Active Period of a TTML segment . 22
5.2.3.4 TTML documents segmentation rules . 22
5.2.3.5 Subtitle stream in the absence of subtit les . 22
5.2.3.6 Continuation of a subtitle across adjacent segments . 22
5.2.3.7 Untimed elements in TTML segments . 23
5.2.3.8 Examples of TTML segmentation . 23
ETSI
---------------------- Page: 3 ----------------------
4 Draft ETSI EN 303 560 V1.1.1 (2018-01)
5.2.4 Synchronization . 23
5.2.4.1 Relationship between MPEG system clock and TTML timeline . 23
5.2.4.2 Failure of TTML segment reception . 24
5.2.4.3 Synchronization examples . 24
5.2.5 Acquisition time . 27
5.3 Font download . 27
5.3.1 Introduction. 27
5.3.2 Font delivery signalling mechanism . 28
5.3.2.1 Overview . 28
5.3.2.2 Linkage descriptor with linkage type 0x20 . 29
5.3.2.2.1 Introduction . 29
5.3.2.2.2 Linkage descriptor with linkage type 0x20 structure . 29
5.3.2.2.3 Linkage descriptor with linkage type 0x20 location, occurrence and prioritization . 30
5.3.2.3 Downloadable Font Information Table (DFIT) . 30
5.3.2.3.1 DFIT structure . 30
5.3.2.3.2 font_info_type in the loop of the DFIS . 32
5.3.3 IP download fonts . 33
5.3.4 Broadcast download fonts . 33
5.3.5 Downloaded font file, font name and font-id association . 33
6 IRD requirements . . 34
6.1 General support . 34
6.2 Forward compatibility . 34
6.3 Support of PSI/SI signalling and subtitle service selection . 34
6.3.1 PSI/SI signalling . 34
6.3.2 Determining which subtitle services can be rendered . 34
6.3.3 Subtitle service selection . 34
6.4 Font support in IRDs . 35
6.4.1 Supported fonts and font family name mapping . 35
6.4.2 Downloadable font retrieval . 35
6.4.3 Font selection for subtitle rendering . 36
6.5 Rendering requirements . 36
6.5.1 Playback free-running when A/V sync lost temporarily . 36
6.5.2 Behaviour during trick play . 36
6.5.3 Subtitle composition with HDR video . 36
6.5.4 Cropping and scaling of video . 37
6.6 Additional TTML processor requirements . 37
Annex A (informative): Change History . 38
History . 39
ETSI
---------------------- Page: 4 ----------------------
5 Draft ETSI EN 303 560 V1.1.1 (2018-01)
Intellectual Property Rights
Essential patents
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 (https://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.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This draft European Standard (EN) 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), and is now submitted for the combined Public Enquiry and Vote phase
of the ETSI standards EN Approval Procedure.
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.
Proposed national transposition dates
Date of latest announcement of this EN (doa): 3 months after ETSI publication
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 6 months after doa
Date of withdrawal of any conflicting National Standard (dow): 6 months after doa
ETSI
---------------------- Page: 5 ----------------------
6 Draft ETSI EN 303 560 V1.1.1 (2018-01)
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
Today's broadcast content can be distributed in many forms and via many different paths. Whilst broadcast services
traditionally relied on bitmap-based subtitles because of processing simplicity, advanced processing and text rendering
have made text-based approaches feasible. These offer more flexibility and better options to improve the user
experience. TTML (Timed Text Markup Language) is established as a common solution for IP-based platforms, but
multiple profiles exist.
In Europe, the EBU Group 'Subtitles in XML' published the EBU-TT-D TTML profile [20] which was adopted by the
DVB DASH specification [6] and by HbbTV [5]. The W3C later published the IMSC1 TTML profiles [4], which were
adopted by ATSC.
There are only minor differences between EBU-TT-D [3], [20] and IMSC1 Text Profile.
The present specification builds on the existing widespread device support for EBU-TT-D [20], in particular through
support for HbbTV, to enable the distribution of TTML subtitles together with audio/video content via broadcast.
Clause 4 specifies TTML subtitle constraints for a default conformance point, to be supported by both EBU-TT-D [3],
[20] and IMSC1 Text Profile compatible processors.
Clause 5 specifies subtitle delivery, including PSI/SI signalling, TS packetisation, TTML segmentation and
synchronization requirements.
Finally clause 6 specifies IRD requirements.
ETSI
---------------------- Page: 6 ----------------------
7 Draft ETSI EN 303 560 V1.1.1 (2018-01)
1 Scope
The present document specifies the transport of TTML [2] subtitle streams in DVB MPEG-2 transport streams,
based on the MPEG-2 system described in ISO/IEC 13818-1 [1]. TTML is an XML-based representation. The present
document provides syntax for delivery of TTML subtitle streams over MPEG-2 transport stream, and is based on
EBU-TT-D [3] compatible with the IMSC1 [4] Text Profile of W3C TTML [2].
2 References
2.1 Normative 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
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://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.
The following referenced documents are necessary for the application of the present document.
[1] ISO/IEC 13818-1: "Information technology -- Generic coding of moving pictures and associated
audio information -- Part 1: Systems".
[2] W3C Recommendation (TTML): "Timed Text Markup Language 1 (TTML1) (Second Edition)".
NOTE: Available at http://www.w3.org/TR/2013/REC-ttml1-20130924/.
[3] EBU Tech 3380 "EBU-TT-D Subtitling Distribution Format", version 1.0.1d.
NOTE: Available at https://tech.ebu.ch/publications/tech3380.
[4] W3C Candidate Recommendation (IMSC1): "TTML Profiles for Internet Media Subtitles and
Captions 1.0.1 (IMSC1)".
NOTE: Available at http://www.w3.org/TR/ttml-imsc1.0.1/.
[5] ETSI TS 102 796: "Hybrid Broadcast Broadband TV".
[6] ETSI TS 103 285: "Digital Video Broadcasting (DVB); MPEG-DASH Profile for Transport of
ISO BMFF Based DVB Services over IP Based Networks".
[7] DVB BlueBook A038: "Digital Video Broadcasting (DVB); Specification for Service Information
(SI) in DVB systems".
NOTE: Available at https://www.dvb.org/resources/public/standards/a038_dvb_spec_july_2017.pdf.
[8] ISO 639-2: "Codes for the representation of names of languages -- Part 2: Alpha-3 code".
[9] ISO/IEC 8859-1: "Information technology -- 8-bit single-byte coded graphic character sets --
Part 1: Latin alphabet No. 1".
[10] W3C Working Group Note: "TTML Media Type Definition and Profile Registry".
NOTE: Available at http://www.w3.org/TR/ttml-profile-registry/.
[11] ETSI EN 301 192: "Digital Video Broadcasting (DVB); DVB specification for data broadcasting".
[12] ETSI TS 102 809: "Digital Video Broadcasting (DVB); Signalling and carriage of interactive
applications and services in hybrid broadcast/broadband environments".
ETSI
---------------------- Page: 7 ----------------------
8 Draft ETSI EN 303 560 V1.1.1 (2018-01)
[13] ETSI TS 102 851: "Digital Video Broadcasting (DVB); Uniform Resource Identifiers (URI) for
DVB Systems".
[14] IETF RFC 1952: "GZIP file format specification version 4.3".
[15] DVB BlueBook A126: "Digital Video Broadcasting (DVB); Allocation of identifiers and codes for
Digital Video Broadcasting (DVB) systems".
NOTE: Available at https://www.dvb.org/resources/public/standards/a126_allocation_identifiers.pdf.
[16] W3C Recommendation (XML): "Extensible Markup Language (XML) 1.0 (Fifth Edition)".
NOTE: Available at https://www.w3.org/TR/2008/REC-xml-20081126/.
[17] EBU Tech 3381: "Carriage of EBU-TT-D in ISOBMFF", version 1.0.
NOTE: Available at https://tech.ebu.ch/publications/tech3381.
[18] W3C Recommendation 13 December 2012 (WOFF): "Web Open Font Format (WOFF) 1.0".
NOTE: Available at http://www.w3.org/TR/2012/REC-WOFF-20121213/.
[19] ISO/IEC 14496-22:2015: "Information technology -- Coding of audio-visual objects --
Part 22: Open Font Format".
[20] EBU Tech 3380: "EBU-TT-D Subtitling Distribution Format", version 1.0.
NOTE: Available at https://tech.ebu.ch/publications/tech3380.
[21] IETF RFC 3986: "Uniform Resource Identifier (URI): Generic Syntax".
2.2 Informative 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
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
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] W3C Recommendation (WCAG): "Web Content Accessibility Guidelines (WCAG) 2.0".
NOTE: Available at https://www.w3.org/TR/2008/REC-WCAG20-20081211/.
[i.2] W3C Candidate Recommendation (CSS): "CSS Fonts Module Level 3: Font matching algorithm".
NOTE: Available at https://www.w3.org/TR/css-fonts-3/#font-matching-algorithm.
[i.3] IEC 61966-2-1:1999: "Multimedia systems and equipment - Colour measurement and
management - Part 2-1: Colour management - Default RGB colour space - sRGB".
ETSI
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9 Draft ETSI EN 303 560 V1.1.1 (2018-01)
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
Intermediate Synchronic Document (ISD): temporally bounded (possibly empty) subset of TTML content during
which no elements change state between active and inactive
NOTE: A TTML document can conceptually be considered as a contiguous sequence of ISDs.
maximum period of activation (MPA): maximum duration a single TTML segment can be active, referred to as T
MPA
Packet IDentifier (PID): transport stream packet identifier
NOTE: See ISO/IEC 13818-1 [1].
PES packet: See ISO/IEC 13818-1 [1].
Presentation Time Stamp (PTS): See ISO/IEC 13818-1 [1].
reserved_zero_future_use: when used in the clause defining the coded bit stream, indicates that the value may be used
in the future for ETSI defined extensions
NOTE: All "reserved_zero_future_use" bits are set to "0".
subtitle segment: basic syntactical element of a subtitle stream
NOTE: The present document is structured to allow other types of subtitle segments to be defined in the future. In
this version of the specification, all subtitle segments are TTML segments.
subtitle service properties: properties defined by TTML subtitling descriptor which include but are not limited to
language, purpose, TTS_suitability, font usage, and qualifier
subtitle service: service that provides subtitling for an MPEG program (DVB service) with a set of subtitle service
properties
subtitle service qualifier variants: set of subtitle services whose subtitle service properties are identical except for
the qualifier_present_flag and qualifier fields in the TTML subtitling descriptor
subtitle stream: stream of subtitle segments carried in transport stream packets identified by the same PID,
containing a single subtitle service
transport stream packet: See ISO/IEC 13818-1 [1].
transport stream: stream of transport stream packets carrying one or more MPEG programs
NOTE: See ISO/IEC 13818-1 [1].
TTML document chunk: self-contained and temporally bounded subset of a TTML document [2]
NOTE: Self-contained in this context means that the document chunk contains all elements to render this subset
except the actual fonts used.
TTML segment: subtitle segment whose payload is an XML serialization of a TTML document chunk, concr
...
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