1、ETSI EN 300 472 VI .3.1 (2003-05) European Sfandard (Telecommunicafions series) Digital Video Broadcasting (DVB); Specification for conveying ITU-R System B Teletext in DVB bitstreams 2 ETSI EN 300 472 VI .3.1 (2003-05) The pre ent d Reference REN/JTC-DVB-143 Keywords broadcasting, digital, DVB, MPE
2、G, teletext, TV, video ETSI 650 Route des Lucioles F-O6921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 O0 Fax: +33 4 93 65 47 16 Siret No 348 623 562 00017 - NAF 742 C Association but non lucratif enregistre la Sous-prfecture de Grasse (06) No 7803/88 Important notice Individual copies of t
3、he present document can be downloaded from: http:lwmv.etsi .arq cument may be made available in more than one electronic version or in print. In any ca e of existing or perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF). In case of dis
4、pute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive within ETSI Secretariat. Users of the present document should be aware that the document may be subject to revision or change of status. Information on the current status of this and other
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6、eproduction in all media. O European Telecommunications Standards Institute 2003. O European Broadcasting Union 2003. All rights reserved. DECTTM, PLUGTESTSTMand UMTSTMare Trade Marks of ETSI registered for the benefit of its Members. TIPHONTM and the TIPHON logo are Trade Marks currently being regi
7、stered by ETSI for the benefit of its Members. 3GPPTM is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. ETSI 3 ETSI EN 300 472 VI .3.1 (2003-05) Contents Intellectual Property Rights . . . . . . . , . . . . . . . . . . . . . . . . . . . . . .
8、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 Foreword 1 2 3 3.1 3.2 4 4.1 4.2 4.3 4.4 5 Scope . References . . . .5 Definitions and abbreviations. .
9、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 . 5 . 6 Insertion of Teletext into MPEG-2 transport multiplex . . . . . . .
10、. .6 6 6 7 7 Teletext decoder model . . . .9 Transport Stream (TS) packet format. PES packet format Syntax for PES data field . Semantics for PES data field Annex A (informative): PTS transmission . 10 History 11 ETSI 4 ETSI EN 300 472 VI .3.1 (2003-05) Intellectual Property Rights IPRs essential or
11、 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 O00 3 14: “Intellectual Property Rights (7PRs); Essential, orpotentially Esse
12、ntial, IPRs notlJied to ETSI in respect ofETSI standards“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (5). All published ETSI deliverables shall include information which directs the reader to the above source of information. Foreword This Europ
13、ean Standard (Telecommunications series) has been produced by Joint 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
14、 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 te
15、levision 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 broadcast
16、ing area; its headquarters is in Geneva. European Broadcasting Union CH-I218 GRAND SACONNEX (Geneva) Switzerland Tel: +41 22 717 21 11 Fax: +41 22 717 24 81 Founded in September 1993, the DVB Project is a market-led consortium of public and private sector organizations in the television industry. It
17、s 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
18、 and the broadcast industry. National transposition dates Date of adoption of this EN: Date of latest announcement of this EN (doa): Date of latest publication of new National Standard or endorsement of this EN (dop/e): Date of withdrawal of any conflicting National Standard (dow): 23 May 2003 3 1 A
19、ugust 2003 29 February 2004 29 February 2004 ETSI 5 ETSI EN 300 472 VI .3.1 (2003-05) 1 Scope The present document specifies the method by which ITU-R System B Teletext (ITU-R Recommendation BT.653 3), also known as EBU Teletext (see EN 300 706 4), may be carried in DVB bitstreams. This transport me
20、chanism is intended to satissl the following requirements: - to support the transcoding of the Teletext data into the Vertical Blanking Interval (VBI) of analogue video. The transcoded signal should be compatible with existing TV receivers with Teletext decoders; the maximum data rate for each Telet
21、ext service is equivalent to 16 lines per field so that the service is always suitable for transcoding into the VBI; - - the transmission mechanism should be capable of transmitting subtitles with accurate timing with respect to the video (i.e. to within or near frame accuracy). A more general data
22、transport mechanism for conveying new types of data services is outside the scope of the present document, but the transport syntax specified here can also be adapted for other data. 2 Re fe re nces The following documents contain provisions which, through reference in this text, constitute provisio
23、ns of the present document. References are either specific (identified by date of publication andor edition number or version number) or non-specific. For a specific reference, subsequent revisions do not apply. For a non-specific reference, the latest version applies. Referenced documents which are
24、 not found to be publicly available in the expected location might be found at htlu:/docbox.etsi.or:eerence. il ISO/IEC 13 8 18-1 : “Information technology - Generic coding of moving pictures and associated audio information: Systems“. ETSI EN 300 468: “Digital Video Broadcasting (DVB); Specificatio
25、n for Service Information (SI) in DVB systems“. ITU-R Recommendation BT.653 : “Teletext systems“. ETSI EN 300 706: “Enhanced Teletext specification“. 21 31 41 3 3.1 Definitions and abbreviations De fi nit ions For the purposes of the present document, the following terms and definitions apply. MPEG-
26、2: Refers to the standard ISO/IEC 13818. Systems coding is defined in part 1 i. Video coding is defined in part 2. Audio coding is defined in part 3 of ISO/IEC 13818. section: syntactic structure used for mapping all service information defined in EN 300 468 into ISO/IEC 13818-1 Transport Stream (TS
27、) packets service: sequence of programmes under the control of a broadcaster which can be broadcast as part of a schedule ETSI 6 ETSI EN 300 472 VI .3.1 (2003-05) Teletext descriptor: See EN 300 468 2, it is used in the Program Specific Information (PSI) Program Map Table (PMT) to identiSl streams w
28、hich carry EBU data. The descriptor is located in a program map section following the relevant ES-info-length field. 3.2 Abbreviations For the purposes of the present document, the following abbreviations apply: DVB MPEG PES PID PMT PSI PTS SI TS TV VBI Digital Video Broadcasting Moving Pictures Exp
29、ert group Packetized Elementary Stream Packet IDentifier Program Map Table Program Specific Information Presentation Time Stamp Service Information Transport Stream Television Vertical Blanking Interval 4 Insertion of Teletext into MPEG-2 transport multiplex Teletext data are conveyed in Packetized
30、Elementary Stream (PES) packets which are carried by Transport Stream (TS) packets as defiied in ISO/IEC 13818-1 i. The Packet Identifier (PID) of a Teletext stream associated with a service is identified in the Program Map Table (PMT) of the Program Specific Information (PSI) for that service. The
31、Teletext data stream is given stream-type value 0x06 (which indicates a PES stream carrying private data). The appropriate ES-info field of the program map section describing Teletext data streams shall contain a Teletext descriptor as defined in EN 300 468 2. A service may include more than one Tel
32、etext data stream, provided that each stream has a different value of data-identifier, and that the streams are distinguishable by their respective Teletext descriptors in the PSI. 4.1 Transport Stream (TS) packet format The standard TS packet syntax and semantics are followed, noting the following
33、constraint: adap tation-field-control only the values “01“ and “10“ are permitted. 4.2 PES packet format The standard PES packet syntax and semantics are followed noting the following constraints: stream-id set to “101 1 1101“ meaning “private-stream-1“. PES-pac ke t-leng th set to the value (N x 18
34、4)-6, where N is an integer, so that the PES packet finishes at the end of a Transport packet. set to “1“ indicating that the Teletext access units are aligned with the PES packets. Data-alignment-indicator PES-header-data-length set to “0x24“. stuffing-byte the PES header is followed by as many stu
35、ffing bytes as are required to make up the header data length, so that the entire PES header is 45 bytes long. ETSI 7 ETSI EN 300 472 VI .3.1 (2003-05) Syntax PES-packet-data-byte these bytes are coded in accordance with the PESdata-field syntax specified below. No. of Identifier bits PTS and other
36、optional fields may be present in the PES header, but the header length is always fixed for streams identified in the Program Specific Information (PSI) by the DVB Teletext descriptor (see EN 300 468 2). NOTE: See annex A. Syntax 4.3 No. of Identifier bits Syntax for PES data field Ox00 to OxOF 0x1
37、O to 0x1 F 0x02 to Ox7F 0x80 to OxFF reserved for future use EBU data reserved for future use user defined for(i=O;iN;i+) data-u n it-id data-unit-length data-field() 1 8 uimsbf 8 uimsbf Data-field for EBU Teletext Table 2: Syntax for Data-field for EBU Teletext 4.4 Semantics for PES data field data
38、-identifier: this 8-bit field identifies the type of data carried in the PES packet. It is coded as in table 3: Table 3: data-identifier I data identifier I value I The data-identifier shall be set to the same value for each PES packet conveying data in the same Teletext data stream. ETSI 8 ETSI EN
39、300 472 VI .3.1 (2003-05) data-unit-id ox00 to oxo1 0x02 0x03 0x04 to Ox7F 0x80 to OxFE OxFF data-unit-id: this 8-bit field identifies the type of data unit. It is coded as in table 4: value reserved for future use EBU Teletext non-subtitle data EBU Teletext subtitle data reserved for future use use
40、r defined data-unit for stuffing I line-offset For streams identified in the PSI by the DVB Teletext descriptor (see EN 300 468 2), only values 0x02, 0x03 and OxFF are permitted. data-unit-length: this 8-bit field indicates the number of bytes in the data unit following the length field. For data un
41、its carrying EBU Teletext data, this field shall always be set to Ox2C. reserved-future-use: this field may be used in the future for ETSI defined extensions. As a default reserved-futureuse bits are set to “1“. Meaning field Daritv = 1 Ifield Daritv = O field-parity: this 1-bit flag specifies the f
42、ield for which the data is intended; the value “1“ indicates the first field of a frame, the value “O“ indicates the second field of a frame. ox00 Ox01 to 0x06 0x07 0x08 line-offset: this 5-bit field specifies the line number on which the Teletext data packet is intended to be presented if it is tra
43、nscoded into the VBI. Within a field, the line-offset numbering shall follow a progressive incremental order except for the undefined line-offset value “O“. The toggling of the field-parity flag indicates a new field. The lineoffset is coded as in table 5: Line number undefined reserved for future u
44、se Line number = 7 Line number = 8 Line number undefined reserved for future use Line number = 320 Line number = 321 Table 5: line-offset 0x1 6 0x1 7 to 0x1 F Line number = 22 reserved for future use Line number = 335 reserved for future use Only values Ox00 and 0x07 to 0x16 are permitted for EBU Te
45、letext data-units in streams identified in the PSI by the DVB Teletext descriptor, see EN 300 468 2. framing-code, magazine-and-packet-address, data-block these fields correspond to the 43 bytes following the clock-run-in sequence of an EBU Teletext data packet as defined in ITU-R Recommendation BT.
46、653 3, and also in EN 300 706 4. Data packets are inserted in the same order as they are intended to arrive at the Teletext decoder or to be transcoded into the VBI. Data bits are inserted in the PES packet in the same order as they would appear in the VBI, e.g. the framing code is 11 100100. ETSI 9
47、 ETSI EN 300 472 VI .3.1 (2003-05) 5 Teletext decoder model The Teletext decoder model is a conceptual model for decoding, which the bitstream is required to satisSl. The decoder model does not spec the operation or behaviour of a real decoder implementation and implementations which do not follow t
48、he architecture or timing of this model are not precluded. A Teletext access unit is defined as a Teletext data packet. The PTS applies to the first access unit following the PTS field. The presentation time is that at which the decoded text is intended to be presented on the screen, or in the case
49、of a transcoding operation, the time at which the access unit is to be inserted in the VBI. The system target decoder has buffers TB, = 480 bytes, and Bttx = 1 504 bytes The transfer rate from TB, to B, is 6,75 Mbit/s. For a transcoding process an access unit is extracted from B, instantaneously whenever a video line of the appropriate number and field-parity is available in the associated video, provided that the system time clock has reached the value of the PTS associ
