1、BRITISH STANDARDBS EN 62261-2:2006Television METADATA Part 2: Data encoding protocol using key-length-valueThe European Standard EN 62261-2:2006 has the status of a British StandardICS 33.160.01; 35.040g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g
2、40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 62261-2:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 May 2007 BSI 2007ISBN 978 0 580 50819 6National forewordThis British St
3、andard was published by BSI. It is the UK implementation of EN 62261-2:2006. It is identical with IEC 62261-2:2005.The UK participation in its preparation was entrusted to Technical Committee EPL/100, Audio, video and multimedia systems and equipment.A list of organizations represented on this commi
4、ttee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments issued since publica
5、tionAmd. No. Date CommentsEUROPEAN STANDARD EN 62261-2 NORME EUROPENNE EUROPISCHE NORM December 2006 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 3
6、5, B - 1050 Brussels 2006 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 62261-2:2006 E ICS 33.160; 35.040 English version Television METADATA Part 2: Data encoding protocol using key-length-value (IEC 62261-2:2005) Mtadonnes des
7、 applications tlvision Partie 2: Protocole de codage des donnes par mthode de longueur de cls(CEI 62261-2:2005) Fernseh-Metadaten Teil 2: Protokoll zur Datencodierung mit Schlssellngenwert (IEC 62261-2:2005) This European Standard was approved by CENELEC on 2006-12-01. CENELEC members are bound to c
8、omply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central
9、Secretariat or to any CENELEC member. This European Standard exists in two official versions (English and German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the
10、 official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Rom
11、ania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Foreword The text of the International Standard IEC 62261-2:2005, prepared by Technical Area 6: Higher data rate storage media, data structure and equipment, of IEC TC 100, Audio, video and multimedia systems and equipment,
12、 was submitted to the formal vote and was approved by CENELEC as EN 62261-2 on 2006-12-01 without any modification. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2007-12-01
13、latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2009-12-01 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 62261-2:2005 was approved by CENELEC as a European Standard without any modification. _ EN 622
14、61-2:2006 2 CONTENTS 1 Scope.5 2 Normative references .5 3 KLV protocol.5 3.1 General .5 3.2 ANSI/SMPTE 298M universal label key .6 3.3 Encoding of the KLV length field .9 3.4 Encoding of data values 10 3.5 Empty metadata items.11 4 KLV coding of individual data items 11 4.1 General .11 4.2 Identifi
15、cation of value data representations .11 5 KLV group coding.12 5.1 General .12 5.2 Universal sets .13 5.3 Global sets13 5.4 Local sets15 5.5 Variable-length packs18 5.6 Fixed-length packs 21 6 Labels 23 Annex A (normative) Glossary of terms24 Annex B (informative) Example usage of Universal Label Ke
16、y26 Annex C (informative) Example of the KLV encoding of a single metadata item .27 Annex D (informative) Example of a universal set 28 Annex E (informative) Example of a global set .29 Annex F (informative) Example of a local set .30 Annex G (informative) Example of a variable-length pack 31 Annex
17、H (informative) Example of a fixed-length pack .32 Annex I (informative) Example of a label33 Bibliography34 Figure 1 KLV encoding.6 Figure 2 KLV coded universal set data structure 14 Figure 3 KLV coded global set data structure.15 Figure 4 KLV coded local set structure.17 Figure 5 Informative illus
18、tration of local set label to global key linking19 Figure 6 KLV coded variable-length pack structure 20 Figure 7 KLV coded fixed-length pack structure .22 Figure 8 UL key for labels 23 Figure B.1 Example of universal label fields for metadata encoding in the SMPTE namespace .26 EN 62261-2:2006 3 Ann
19、ex ZA (normative) Normative references to international publications with theircorresponding European publications 35Table 1 KLV fields for encoding of data6 Table 2 Field descriptions for the universal label key for the KLV encoding of data 7 Table 3 UL designators for octets 5 through 78 Table 4 F
20、ield descriptions for the UL key for the KLV encoding of universal sets .14 Table 5 Field descriptions for the UL key for global set encoding .16 Table 6 Coding of registry designator (octet 6) for global set syntax 17 Table 7 Field descriptions for the UL key for local set encoding .17 Table 8 Codi
21、ng of registry designator (octet 6) for local set syntax 18 Table 9 Field descriptions for the UL key for variable-length pack encoding.20 Table 10 Coding of registry designator (octet 6) for variable-length pack syntax 20 Table 11 Field descriptions for the UL key for fixed-length pack encoding22 T
22、able 12 Field descriptors for the UL key for labels23 Table B.1 Expanded example of SMPTE universal label fields for metadata encoding26 Table C.1 Informative example of KLV individual value encoding of metadata27 Table D.1 Informative example of KLV universal set encoding of metadata (octets separa
23、ted by spaces for readability) .28 Table E.1 Informative example of KLV global set encoding of metadata (octets separated by spaces for readability) .29 Table F.1 Informative example of KLV local set encoding of metadata (octets separated by spaces for readability) .30 Table G.1 Informative example
24、of KLV variable-length pack encoding of metadata (octets separated by spaces for readability)31 Table H.1 Informative example of KLV fixed-length pack encoding of metadata (octets separated for readability) 32 Table I.1 Example of a label.33 EN 62261-2:2006 4 TELEVISION METADATA Part 2: Data encodin
25、g protocol using key-length-value 1 Scope This part of IEC 62261 defines an octet-level data encoding protocol for representing data items and data groups. This protocol defines a data structure which is independent of the application or transportation method used. The standard defines a key-length-
26、value (KLV) triplet as a data interchange protocol for data items where the key identifies the data, the length specifies the length of the data, and the value is the data itself. The KLV protocol provides a common interchange for all compliant applications irrespective of the method of implementati
27、on or transport. The standard also provides methods for combining associated KLV triplets in data sets where the set of KLV triplets is itself coded with KLV data coding protocol. Such sets can be coded in either full form (universal sets) or in one of four increasingly bit-efficient forms (global s
28、ets, local sets, variable-length packs, and fixed-length packs). The standard provides a definition of each of these data constructs. The encoding octet range (length of the payload) specified in this standard may generate unusually large volumes of data. Consequently, a specific application of KLV
29、encoding is capable of only a limited operating data range and those details shall be defined in a relevant application document. Of necessity, keys and other reference data have to be globally unique if clashes are to be avoided. The IEC will therefore, from time to time, designate other bodies to
30、act as its registration authority and agent in this respect; it is important to note that, as a result of this, registrations will always contain the designator of the registration authority acting at the time of registration and not that of the IEC (unless the IEC was acting directly as its own reg
31、istration authority). A mixture of registration authority designators is therefore to be expected. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the lates
32、t edition of the referenced document (including any amendments) applies. ISO/IEC 8825-1:2002, (ITU-T X.690), Information Technology ASN.1 Encoding Rules Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER), and Distinguished Encoding Rules (DER) ANSI/SMPTE 298M:1997, Televisio
33、n Universal Labels for Unique Identification of Digital Data 3 KLV protocol 3.1 General Table 1 and Figure 1 present an introductory view of the KLV protocol for encoding data. The data encoded may be a single data item or a data group. The coding of data items is described in Clause 4 while the cod
34、ing of data groups is described in Clause 5 of this standard. EN 62261-2:2006 5 The KLV coding protocol is composed of a universal label (UL) identification key (UL key), followed by a numeric length (value length), followed by the data value. The composition of the UL key is described in 3.2 of thi
35、s standard. The length of the full UL key shall be 16 octets. The length field is described in 3.3 of this standard. The value is described in 3.4 of this standard. The value is a sequence of octets of the data type as specified in a relevant standard and is not further specified by the KLV protocol
36、. The length of the value field is variable and any limitations are defined in a relevant defining standard. Table 1 KLV fields for encoding of data Field Description Length Content/Format UL key Universal label for identification of the value 16 octets Subclause 3.2 Length Length of the value field
37、 Defined in a relevant dictionary, essence, application standard, but variable length Subclause 3.3 Value Value associated with the UL key Variable Subclause 3.4 ValueUL Key Length 16 octets BER Variable Length Octets LengthIEC 1161/05Figure 1 KLV encoding The bit-order (lsb or msb first) for KLV en
38、coding shall be that of the transport used to carry the information. 3.2 ANSI/SMPTE 298M universal label key 3.2.1 General KLV coding protocol shall use a 16-word universal label (UL) generated according to ANSI/SMPTE 298M as the UL key to identify the data in the value field but with the appropriat
39、e registration authoritys 4-octet prefix following the OID tag and length byte. Each word in the ANSI/SMPTE 298M UL is coded using the basic encoding rules (BER) for the encoding of an object identifier value specified in ISO/IEC 8825-1, 8.19. Each word of the UL key shall be limited to the range 0x
40、00 to 0x7F and shall be represented by a single octet. The UL key shall have left-to-right significance with the first octet as the most significant. The leftmost octet of value 0x00 in the UL key shall define the termination of the label and all octets of lower significance shall also be set to 0x0
41、0. Octets of value 0x00 shall have no significance to the meaning of the UL key. The full UL key consists of a 16-octet field including an object ID (OID) and the UL size (0x0E indicating a total UL key size of 16 octets) followed by a UL code and a series of sub-identifiers which shall define the U
42、L designators. The first two UL designators shall have reserved values for the KLV coding protocol according to this standard. EN 62261-2:2006 6 NOTE The ANSI/SMPTE UL itself adopts KLV coding with the object ID as the key, the UL size as the length, and the UL designators as the value. When applyin
43、g the ANSI/SMPTE UL to the coding of data according to this standard, these fields shall be categorized as the UL header, UL designators, and item descriptor as shown in Table 2. Annex B shows an informative example of a metadata UL key in tabular and figure formats. Note that decoders which recogni
44、ze the UL key but do not want to, or cannot, decode the associated value, may ignore the item and shall continue the decoding process of subsequent items using the length value to skip the value of the undecoded item. If decoders only store or forward the item, they shall forward the item unaltered.
45、 3.2.2 UL designators Table 3 defines octet values for the designators to be used in octets 5 through 7 of the UL designators. Standards and recommended practices which define a UL key with the value of octet 5 (registry category designator) in the range 0x01 to 0x04 shall register the full UL key o
46、r keys used with the IECs designated registration authority in the registry identified by octets 6 and 7 (registry designator and structure designator). Table 2 Field descriptions for the universal label key for the KLV encoding of data No. Field Description Length Content/format UL header 1 OID Obj
47、ect identifier 1 octet Always 0x06 2 UL size 16-octet size of the UL 1 octet Always 0x0E UL designators 3 UL code Concatenated subidentifiers ISO, ORG 1 octet Always 0x0B 4 Registration authority designator Registration authority subidentifier 1 octet Dependant on Registration Authority (for example
48、, 0x34 for SMPTE) 5 Registry category designation Registry category designator identifying the category of registry described (for example, dictionaries) 1 octet See Table 3 6 Registry designator Registry designator identifying the specific registry in a category (for example, metadata dictionary) 1
49、 octet See Table 3 7 Structure designator Designator of the structure variant within the given registry 1 octet Subclause 3.2.3 8 Version number Version of the given registry which first defines the item specified by the item designator 1 octet Incrementing number 9-16 Item descriptor Unique identification of the particular item within the context of the UL designator 8 octets See relevant standard and version EN 62261-2:2006 7 Table 3 UL designators for octets
