ETSI EN 303 560-2018 Digital Video Broadcasting (DVB) TTML subtitling systems (V1 1 1).pdf

1、 ETSI EN 303 560 V1.1.1 (2018-05) Digital Video Broadcasting (DVB); TTML subtitling systems EUROPEAN STANDARD ETSI ETSI EN 303 560 V1.1.1 (2018-05) 2 Reference DEN/JTC-DVB-375 Keywords broadcast, digital, DVB, subtitle, TV ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33

2、 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non lucratif enregistre la Sous-Prfecture 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

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6、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 reprod

7、uction in all media. ETSI 2018. European Broadcasting Union 2018. All rights reserved. DECTTM, PLUGTESTSTM, UMTSTMand the ETSI logo are trademarks of ETSI registered for the benefit of its Members. 3GPPTM and LTETMare trademarks of ETSI registered for the benefit of its Members and of the 3GPP Organ

8、izational Partners. oneM2M logo is protected for the benefit of its Members. GSMand the GSM logo are trademarks registered and owned by the GSM Association. ETSI ETSI EN 303 560 V1.1.1 (2018-05) 3 Contents Intellectual Property Rights 5g3Foreword . 5g3Modal verbs terminology 6g3Introduction 6g31 Sco

9、pe 7g32 References 7g32.1 Normative references . 7g32.2 Informative references 8g33 Definitions and abbreviations . 9g33.1 Definitions 9g33.2 Abbreviations . 10g34 Default DVB TTML subtitle conformance point . 11g34.1 Introduction 11g34.2 Document Constraints 11g34.2.1 General 11g34.2.2 Regions . 12

10、g34.2.3 Document complexity . 12g34.2.4 Document encoding 12g34.2.5 Namespaces 12g34.2.6 Guidance for document authors and content providers (informative) 12g34.2.6.1 Overview . 12g34.2.6.2 Font mapping for generic font family names 12g34.2.6.3 Default text colour. 13g34.2.6.4 Requirement for suppor

11、t of optional features 13g34.2.6.5 Specifying active area . 13g35 Delivery 13g35.1 IP delivery 13g35.2 Broadcast TS delivery 13g35.2.1 PSI/SI signalling . 13g35.2.1.1 TTML subtitling descriptor . 13g35.2.1.2 Example TTML profile signalling 17g35.2.1.2.1 Signalling conformance only to the default con

12、formance point 17g35.2.1.2.2 Signalling conformance to only EBU-TT-D . 17g35.2.1.2.3 Signalling conformance with EBU-TT-D and the default conformance point 17g35.2.1.2.4 Signalling conformance to only IMSC1 Text Profile 18g35.2.1.3 Presentation properties in qualifier field . 18g35.2.1.4 Component d

13、escriptors for TTML subtitles 19g35.2.2 TS packetization . 19g35.2.2.1 PES packet format and carriage in the TS . 19g35.2.2.2 PES packet payload format for TTML subtitling 20g35.2.2.2.1 General PES payload field syntax and segment types . 20g35.2.2.2.2 Occurrences of segments in one PES packet . 21g

14、35.2.2.2.3 Uncompressed TTML document subtitle segment 21g35.2.2.2.4 gzip compressed TTML document subtitle segment . 21g35.2.3 TTML segmentation . 21g35.2.3.1 General 21g35.2.3.2 Concept of ISDs 22g35.2.3.3 Active Period of a TTML segment . 22g35.2.3.4 TTML documents segmentation rules . 22g35.2.3.

15、5 Subtitle stream in the absence of subtitles . 22g35.2.3.6 Continuation of a subtitle across adjacent segments . 22g35.2.3.7 Untimed elements in TTML segments 23g35.2.3.8 Examples of TTML segmentation . 23g3ETSI ETSI EN 303 560 V1.1.1 (2018-05) 4 5.2.4 Synchronization 23g35.2.4.1 Relationship betwe

16、en MPEG system clock and TTML timeline 23g35.2.4.2 Failure of TTML segment reception . 24g35.2.4.3 Synchronization examples 24g35.2.5 Acquisition time 27g35.3 Font download 27g35.3.1 Introduction. 27g35.3.2 Font delivery signalling mechanism . 28g35.3.2.1 Overview. 28g35.3.2.2 Linkage descriptor wit

17、h linkage type 0x20 . 29g35.3.2.2.1 Introduction . 29g35.3.2.2.2 Linkage descriptor with linkage type 0x20 structure . 29g35.3.2.2.3 Linkage descriptor with linkage type 0x20 location, occurrence and prioritization 30g35.3.2.3 Downloadable Font Information Table (DFIT) . 30g35.3.2.3.1 DFIT structure

18、 . 30g35.3.2.3.2 font_info_type in the loop of the DFIS 32g35.3.3 IP download fonts . 33g35.3.4 Broadcast download fonts . 33g35.3.5 Downloaded font file, font name and font-id association . 33g36 IRD requirements . 34g36.1 General support 34g36.2 Forward compatibility 34g36.3 Support of PSI/SI sign

19、alling and subtitle service selection 34g36.3.1 PSI/SI signalling . 34g36.3.2 Determining which subtitle services can be rendered . 34g36.3.3 Subtitle service selection 34g36.4 Font support in IRDs 35g36.4.1 Supported fonts and font family name mapping . 35g36.4.2 Downloadable font retrieval . 35g36

20、.4.3 Font selection for subtitle rendering . 36g36.5 Rendering requirements . 36g36.5.1 Playback free-running when A/V sync lost temporarily . 36g36.5.2 Behaviour during trick play 36g36.5.3 Subtitle composition with HDR video 36g36.5.4 Cropping and scaling of video 37g36.6 Additional TTML processor

21、 requirements . 37g3Annex A (informative): Change History 38g3History 39g3ETSI ETSI EN 303 560 V1.1.1 (2018-05) 5 Intellectual Property Rights Essential patents IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information pertaining to these essen

22、tial 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

23、 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)

24、 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,

25、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 J

26、oint Technical Committee (JTC) Broadcast of the European Broadcasting Union (EBU), Comit Europen 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 standar

27、ds 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 br

28、oadcasting 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

29、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 d

30、esigning 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 int

31、erfacing, 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 ETSI EN 303 560 V1.1.1 (2018-05) 6 National transposition dates Date of adoption of this EN

32、: 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 docu

33、ment “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

34、when used in direct citation. Introduction Todays 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 ap

35、proaches 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

36、20 which was adopted by the DVB DASH specification as defined in ETSI TS 103 285 6 and by HbbTVas 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 sp

37、ecification 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 sup

38、ported 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 ETSI EN 303 560 V1.1.1 (2018-05) 7 1

39、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 transp

40、ort 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 ver

41、sion 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 incl

42、uded 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

43、 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/publ

44、ications/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 Profil

45、e 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: “C

46、odes 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

47、:/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“

48、. ETSI ETSI EN 303 560 V1.1.1 (2018-05) 8 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

49、 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