1、BSI Standards PublicationBS ISO/IEC 23008-10:2015Information technology High efficiency codingand media delivery inheterogeneous environmentsPart 10: MPEG Media Transport ForwardError Correction (FEC) codesBS ISO/IEC 23008-10:2015 BRITISH STANDARDNational forewordThis British Standard is the UK impl
2、ementation ofISO/IEC 23008-10:2015.The UK participation in its preparation was entrusted to Technical Committee IST/37, Coding of picture, audio, multimedia and hypermedia information.A list of organizations represented on this committee can be obtained on request to its secretary.This publication d
3、oes not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2015.Published by BSI Standards Limited 2015ISBN 978 0 580 83300 7 ICS 35.040 Compliance with a British Standard cannot confer immunity from leg
4、al obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 May 2015.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dInformation technology High efficiency coding and media delivery in heterogeneous environment
5、s Part 10: MPEG Media Transport Forward Error Correction (FEC) codesTechnologies de linformation Codage haute efficacit et livraison des medias dans des environnements htrognes Partie 10: Codes de correction derreur anticipe pour le transport des medias MPEGINTERNATIONAL STANDARDISO/IEC 23008-10Refe
6、rence number ISO/IEC 23008-10:2015(E)First edition 2015-04-15 ISO/IEC 2015BS ISO/IEC 23008-10:2015ii ISO/IEC 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO/IEC 2015All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any fo
7、rm or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56
8、CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandISO/IEC 23008-10:2015(E)BS ISO/IEC 23008-10:2015ISO/IEC 23008-10:2015(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms, definitions, symbols, and abbreviated
9、 terms . 13.1 Terms and definitions . 13.2 Symbols and abbreviated terms. 23.3 Conventions . 24 Overview . 25 FEC Code Points 36 Specification for Reed-Solomon Codes 36.1 Introduction 36.2 Generator matrix . 47 Specification for Structured Low-Density Parity-Check (S-LDPC) Codes . 47.1 Introduction
10、47.2 Structured LDPC Codes 57.3 Creating Parity-Check Matrix . 57.4 Encoding Algorithm 67.5 Decoding Algorithm 77.6 Base matrix 78 Specification 6330 code and RaptorQ LA code.118.1 Introduction . 118.2 6330 code . 128.3 RaptorQ LA 128.3.1 RaptorQ LA First Encoding Step Intermediate symbol generation
11、 . 138.3.2 Layer-Aware RaptorQ Second Encoding Step 158.3.3 Layer-Aware RaptorQ Decoding 159 Specification for FireFort Low Density Generate Matrix (FireFort-LDGM) codes169.1 Introduction . 169.2 FireFort Low Density Generator Matrix (FireFort-LDGM) Codes 169.2.1 Definition . 169.2.2 FF-LDGM-Specifi
12、c Elements 179.2.3 Parity Check Matrix of FF-LDGM Scheme 189.2.4 Creating a Sparse Matrix 189.2.5 Creating a Punctured Sparse Matrix 229.2.6 Source symbol division scheme . 249.2.7 Structured interleaving and de-interleaving scheme 259.2.8 FF-LDGM code Encoding Algorithm .259.2.9 FF-LDGM code Decodi
13、ng Algorithm .269.3 Layer-Aware FireFort-LDGM (LA FireFort-LDGM) Codes .269.3.1 Specification of the LA FF-LDGM Scheme .269.3.2 Encoding Algorithm .279.3.3 Decoding Algorithm .2710 Specification for FEC code algorithms in SMPTE 2022-1.27Bibliography .28 ISO/IEC 2015 All rights reserved iiiContents P
14、ageBS ISO/IEC 23008-10:2015ISO/IEC 23008-10:2015(E)ForewordISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the dev
15、elopment of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governm
16、ental, in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Dir
17、ectives, Part 1. In particular the different approval criteria needed for the different types of document should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some
18、of the elements of this document may be the subject of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent d
19、eclarations received (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as informati
20、on about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/IEC JTC 1, Information technology, SC 29, Coding of audio, picture, multimedia and hypermedia informati
21、on.ISO/IEC 23008 consists of the following parts, under the general title Information technology High efficiency coding and media delivery in heterogeneous environments: Part 1: MPEG media transport (MMT) Part 2: High efficiency video coding (HEVC) Part 3: 3D Audio Part 10: MPEG Media Transport Forw
22、ard Error Correction (FEC) codes Part 11: MPEG Media Transport Composition Informationiv ISO/IEC 2015 All rights reservedBS ISO/IEC 23008-10:2015ISO/IEC 23008-10:2015(E)IntroductionThis part of ISO/IEC 23008 specifies application level forward error correction (FEC) codes which can be used with appl
23、ication level-forward error correction (AL-FEC) framework of ISO/IEC 23008-1 MPEG Media Transport (MMT) to provide reliable delivery in IP network and non IP network environments that are prone to packet losses. ISO/IEC 2015 All rights reserved vBS ISO/IEC 23008-10:2015ISO/IEC 23008-10:2015(E)BS ISO
24、/IEC 23008-10:2015Information technology High efficiency coding and media delivery in heterogeneous environments Part 10: MPEG Media Transport Forward Error Correction (FEC) codes1 ScopeThis part of ISO/IEC 23008 specifies application level forward error correction (FEC) codes which can be used with
25、 AL-FEC framework of ISO/IEC 23008-1 MPEG Media Transport to provide reliable delivery in IP network and non IP network environments that are prone to packet losses.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable f
26、or its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO/IEC 23008-1, Information technology High efficiency coding and media delivery in heterogeneous environments Part 1: M
27、PEG media transport (MMT)IETF RFC 5170, Low Density Parity Check (LDPC) Staircase and Triangle Forward Error Correction (FEC) Schemes, June 2008IETF RFC 5510, Reed-Solomon Forward Error Correction (FEC) Schemes, April 2009IETF RFC 6330, RaptorQ Forward Error Correction Scheme for Object Delivery, Au
28、gust 2011SMPTE2022-1, Forward Error Correction for Real-Time Video/Audio Transport Over IP Networks3 Terms, definitions, symbols, and abbreviated termsFor the purposes of this document, the following terms and definitions apply.3.1 Terms and definitions3.1.1code rateratio between the number of sourc
29、e symbols and the number of encoding symbols3.1.2encoding symbolunit of data generated by the encoding process3.1.3encoding symbol blockset of encoding symbols from the encoding process of a source symbol block3.1.43FEC codealgorithm for encoding data such that the encoded data flow is resilient to
30、data lossINTERNATIONAL STANDARD ISO/IEC 23008-10:2015(E) ISO/IEC ISO pub-date year All rights reserved 1BS ISO/IEC 23008-10:2015ISO/IEC 23008-10:2015(E)3.1.5FEC payload IDidentifier that identifies the contents of a MMT packet with respect to the MMT FEC scheme3.1.6repair symbolencoding symbol that
31、is not a source symbol3.1.7repair symbol blockset of repair symbols which can be used to recover lost source symbols3.1.8source symbolunit of data used during the encoding process3.1.9source symbol blockset of source symbols which is used to generate repair symbol block by FEC code3.1.10systematic c
32、odeany error correction code in which the source symbols are part of output encoded symbols3.2 Symbols and abbreviated termsFor the purpose of this document, the symbols and abbreviated terms given below apply.AL-FEC application layer (level) forward error correctionFEC forward error correctionLA la
33、yer awareLA-FEC layer aware forward error correctionLDGM low density generator matrixLDPC low density parity checkMMT MPEG media transportRS Reed-SolomonS-LDPC structured low density parity check3.3 ConventionsThe following conventions apply in this document: The Big Endian number representation sch
34、eme is used.4 OverviewThis part of ISO/IEC 23008 specifies application level forward error correction (FEC) codes. All codes specified in this part are systematic codes.This specification defines six FEC code algorithms which each FEC code algorithm shall generate a repair symbol block from a source
35、 symbol block as shown in Figure 1. The source symbol block consists 2 ISO/IEC 2015 All rights reservedBS ISO/IEC 23008-10:2015ISO/IEC 23008-10:2015(E)of K source symbols of size T (in bytes) and the repair symbol block consists of P repair symbols of size T (in bytes).Figure 1 Input and Output of F
36、EC code5 FEC Code PointsTable 1 specifies the code points for the FEC code algorithms specified in this part of ISO/IEC 23008. The FEC code algorithms themselves are specified in Clauses 6 to 10.Table 1 FEC Code Algorithms and Its Code PointCode Point FEC Code Algorithm0 Reserved for ISO use1 RS cod
37、e (sub-Clause 6)2 S_LDPC code (sub-Clause 7)3 6330 code (sub-Clause 8.2)4 RaptorQ LA code (sub-Clause 8.3)5 FireFort-LDGM code (sub-Clause 9)6 FEC code algorithm in SMPTE 2022-1 (sub-Clause 10)7 255 Reserved for ISO useNOTE When one of the FEC code algorithms specified in this specification is used
38、for MMT AL-FEC framework, fec_code_id_for_repair_flow field as defined in ISO/IEC 23008-1:2014 Annex C.6 is set to its corresponding code point as specified in Table 1.6 Specification for Reed-Solomon Codes6.1 IntroductionIn this clause, the following notations are used. K: number of source symbols
39、in a source symbol block P: number of repair symbols in a repair symbol block ISO/IEC 2015 All rights reserved 3BS ISO/IEC 23008-10:2015ISO/IEC 23008-10:2015(E) G = I; A: a systematic generator matrix for K+P, K-RS code where I is the identity matrix of order K and A is a K P matrix.A (N, K) ReedSol
40、omon code is a linear block code of length N (over Galois Field F) with dimension K and minimum Hamming distance N K + 1. The ReedSolomon code is optimal in the sense that the minimum distance has the maximum value possible for a linear code of size (N, K); this is known as the Singleton bound. Such
41、 a code is also called a maximum distance separable (MDS) code.The clause 8 of IETF RFC5510 gives full specification of the RS code for the erasure channel and especially, the clause 8.2.1 of IETF RFC5510 gives encoding principle for RS encoding algorithm. The generate matrix G perfectly characteriz
42、es the RS code. In this specification, it specifies only the case when m = 8 (over GF(28) with the generator matrix given in the sub-clause 6.2. Therefore, an encoding symbol block shall be generated from a source symbol block by the given generator matrix in the sub-clause 6.2 and this FEC code sha
43、ll output the repair symbol block of the encoding symbol block.6.2 Generator matrixThe generator matrix G has the form G = I; A where I is an identity matrix of size K and A is a K P matrix, (K + P) 255. Let be the root of the polynomial 1 + x2+ x3+ x4+ x8which is the primitive polynomial of degree
44、8 given in sub-clause 8.1 of IETF RFC5510. The non-zero elements of the finite filed GF(28) are generated by a primitive element and the elements of GF(28) are represented by bytes (group of 8 bits), using the polynomial base representation, with (7, 6, 5, 4, 3, 2, , 1) as a basis. The root is thus
45、represented as: = 00000010. For RS code specified in this specification, the matrix A is a Cauchy matrix which shall have entriesAi,j= 1/(xi+ yj) for 0 i = K shall be generated as defined in clause 5.3 of IETF RFC 6330.8.3 RaptorQ LARaptorQ LA extends the 6330 code for efficient support of LA-FEC as
46、 defined in ISO/IEC 23008-1.This sub-clause extends “5.3.3 First Encoding Step: Intermediate Symbol Generation” and sub-clause “5.3.4 Second Encoding Step: Encoding” of IETF RFC 6330. Relevant terminology and algorithms are specified in IETF RFC 6330 with the following additional definitions:Kxis th
47、e number of source symbols in the source block of media layer x (cf. K in sub-clause 5.1.2 in IETF RFC 6330).Kxis the number of source symbols in the extended source block of media layer x (cf. K in sub-clause 5.1.2 in IETF RFC 6330).Pxis the number of parity symbols of media layer x.Lxdenotes the n
48、umber of intermediate symbols for a single extended source block of media layer x (cf. L in sub-clause 5.1.2 in IETF RFC 6330).Cxdenotes an array of intermediate symbols, Cx0, . CxLx-1, of media layer xEncK, C ,(d, a, b, d1, a1, b1) denotes an encoding symbol generator (cf. sub-clause 5.3.5.3 in IET
49、F RFC 6330).ISI is the internal symbol ID (cf. sub-clause 5.3.1 in IETF RFC 6330).ESI is the encoded symbol ID (cf. sub-clause 5.3.1 in IETF RFC 6330).G_ENCm_LA_zis the LA-FEC z-th extension matrix of the G_ENC matrix of media layer m.Matrix A is the constraint matrix in calculation process of intermediate symbols in the first encoding step of the 6330 code process as used for the code point in sub-clause 8.2 (cf. Figure 5 in sub-clause 5.3.3 in IETF RFC 6330). Matrix A is illustra
