ISO/IEC 23008-10:2015
(Main)Information technology — High efficiency coding and media delivery in heterogeneous environments — Part 10: MPEG media transport forward error correction (FEC) codes
Information technology — High efficiency coding and media delivery in heterogeneous environments — Part 10: MPEG media transport forward error correction (FEC) codes
ISO/IEC 23008-10 specifies application level forward error correction (FEC) codes which can be used with 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.
Technologies de l'information — Codage à haute efficacité et livraison des medias dans des environnements hétérogènes — Partie 10: Codes de correction d'erreur anticipée pour le transport des medias MPEG
General Information
Standards Content (Sample)
INTERNATIONAL ISO/IEC
STANDARD 23008-10
First edition
2015-04-15
Information technology — High
efficiency coding and media delivery
in heterogeneous environments —
Part 10:
MPEG Media Transport Forward Error
Correction (FEC) codes
Technologies de l’information — Codage à haute efficacité et livraison
des medias dans des environnements hétérogènes —
Partie 10: Codes de correction d’erreur anticipée pour le transport
des medias MPEG
Reference number
ISO/IEC 23008-10:2015(E)
©
ISO/IEC 2015
---------------------- Page: 1 ----------------------
ISO/IEC 23008-10:2015(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2015
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
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 ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO/IEC 2015 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/IEC 23008-10:2015(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols, and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Symbols and abbreviated terms. 2
3.3 Conventions . 2
4 Overview . 2
5 FEC Code Points . 3
6 Specification for Reed-Solomon Codes . 3
6.1 Introduction . 3
6.2 Generator matrix . 4
7 Specification for Structured Low-Density Parity-Check (S-LDPC) Codes .4
7.1 Introduction . 4
7.2 Structured LDPC Codes . 5
7.3 Creating Parity-Check Matrix . 5
7.4 Encoding Algorithm . 6
7.5 Decoding Algorithm . 7
7.6 Base matrix . 7
8 Specification 6330 code and RaptorQ LA code.11
8.1 Introduction .11
8.2 6330 code .12
8.3 RaptorQ LA .12
8.3.1 RaptorQ LA First Encoding Step .
Intermediate symbol generation .13
8.3.2 Layer-Aware RaptorQ Second Encoding Step .15
8.3.3 Layer-Aware RaptorQ Decoding .15
9 Specification for FireFort Low Density Generate Matrix (FireFort-LDGM) codes.16
9.1 Introduction .16
9.2 FireFort Low Density Generator Matrix (FireFort-LDGM) Codes .16
9.2.1 Definition .16
9.2.2 FF-LDGM-Specific Elements .17
9.2.3 Parity Check Matrix of FF-LDGM Scheme .18
9.2.4 Creating a Sparse Matrix .18
9.2.5 Creating a Punctured Sparse Matrix .22
9.2.6 Source symbol division scheme .24
9.2.7 Structured interleaving and de-interleaving scheme .25
9.2.8 FF-LDGM code Encoding Algorithm .25
9.2.9 FF-LDGM code Decoding Algorithm .26
9.3 Layer-Aware FireFort-LDGM (LA FireFort-LDGM) Codes .26
9.3.1 Specification of the LA FF-LDGM Scheme .26
9.3.2 Encoding Algorithm .27
9.3.3 Decoding Algorithm .27
10 Specification for FEC code algorithms in SMPTE 2022-1.27
Bibliography .28
© ISO/IEC 2015 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/IEC 23008-10:2015(E)
Foreword
ISO (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 development 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-governmental, 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 Directives, 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 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 declarations 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 information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/IEC JTC 1, Information technology, SC 29, Coding of
audio, picture, multimedia and hypermedia information.
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 Forward Error Correction (FEC) codes
— Part 11: MPEG Media Transport Composition Information
iv © ISO/IEC 2015 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/IEC 23008-10:2015(E)
Introduction
This part of ISO/IEC 23008 specifies application level forward error correction (FEC) codes which can
be used with application 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 v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO/IEC 23008-10:2015(E)
Information technology — High efficiency coding and
media delivery in heterogeneous environments —
Part 10:
MPEG Media Transport Forward Error Correction (FEC) codes
1 Scope
This part of ISO/IEC 23008 specifies application level forward error correction (FEC) codes which can
be used with 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 references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for 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: MPEG media transport (MMT)
IETF RFC 5170, Low Density Parity Check (LDPC) Staircase and Triangle Forward Error Correction (FEC)
Schemes, June 2008
IETF RFC 5510, Reed-Solomon Forward Error Correction (FEC) Schemes, April 2009
IETF RFC 6330, RaptorQ Forward Error Correction Scheme for Object Delivery, August 2011
SMPTE2022-1, Forward Error Correction for Real-Time Video/Audio Transport Over IP Networks
3 Terms, definitions, symbols, and abbreviated terms
For the purposes of this document, the following terms and definitions apply.
3.1 Terms and definitions
3.1.1
code rate
ratio between the number of source symbols and the number of encoding symbols
3.1.2
encoding symbol
unit of data generated by the encoding process
3.1.3
encoding symbol block
set of encoding symbols from the encoding process of a source symbol block
3.1.4
3FEC code
algorithm for encoding data such that the encoded data flow is resilient to data loss
© ISO/IEC ISO pub-date year – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO/IEC 23008-10:2015(E)
3.1.5
FEC payload ID
identifier that identifies the contents of a MMT packet with respect to the MMT FEC scheme
3.1.6
repair symbol
encoding symbol that is not a source symbol
3.1.7
repair symbol block
set of repair symbols which can be used to recover lost source symbols
3.1.8
source symbol
unit of data used during the encoding process
3.1.9
source symbol block
set of source symbols which is used to generate repair symbol block by FEC code
3.1.10
systematic code
any error correction code in which the source symbols are part of output encoded symbols
3.2 Symbols and abbreviated terms
For the purpose of this document, the symbols and abbreviated terms given below apply.
AL-FEC application layer (level) forward error correction
FEC forward error correction
LA layer aware
LA-FEC layer aware forward error correction
LDGM low density generator matrix
LDPC low density parity check
MMT MPEG media transport
RS Reed-Solomon
S-LDPC structured low density parity check
3.3 Conventions
The following conventions apply in this document:
— The Big Endian number representation scheme is used.
4 Overview
This 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 symbol block as shown in Figure 1. The source symbol block consists
2 © ISO/IEC 2015 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/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 FEC code
5 FEC Code Points
Table 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 Point
Code Point FEC Code Algorithm
0 Reserved for ISO use
1 RS code (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 use
NOTE When one of the FEC code algorithms specified in this specification is used 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 Codes
6.1 Introduction
In this clause, the following notations are used.
— K: number of source symbols in a source symbol block
— P: number of repair symbols in a repair symbol block
© ISO/IEC 2015 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO/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) Reed–Solomon code is a linear block code of length N (over Galois Field F) with dimension K
and minimum Hamming distance N – K + 1. The Reed–Solomon 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 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 characterizes the RS code. In this specification, it specifies only the case
8
when m = 8 (over GF(2 )) 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 shall output the repair symbol block of the encoding symbol block.
6.2 Generator matrix
The generator matrix G has the form G = [I; A] where I is an identity matrix of size K and A is a K × P
2 3 4 8
matrix, (K + P) ≤ 255. Let α be the root of the polynomial 1 + x + x + x + x which is the primitive
polynomial of degree 8 given in sub-clause 8.1 of IETF RFC5510. The non-zero elements of the finite
8 8
filed GF(2 ) are generated by a primitive element α and the elements of GF(2 ) are represented by bytes
7 6 5 4 3 2
(group of 8 bits), using the polynomial base representation, with (α , α , α , α , α , α , α, 1) as a basis.
The root α is thus represented as: α = 00000010. For RS code specified in this specification, the matrix
A is a Cauchy matrix which shall have entries
A = 1/(x + y ) for 0 ≤ i < K and 0 ≤ j < P
i,j i j
8
where x and y are elements in GF(2 ) and are defined as:
i j
254 – i j
x = α , and y = α .
i j
Therefore, the matrix A is given by
11 11
xy++xy xy++xy
00 01 02PP−−01
11 11
xy++xy xy++xy
10 11 12PP− 1 −−1
A=
11 11
xy++xy xy++xy
KK−−20 21 KP−−22 KP−−21
11 11
xy+ x +++yx yx + y
KK−−10 1 11KP−−21KP−−1
NOTE Any submatrix of the Cauchy matrix is invertible.
7 Specification for Structured Low-Density Parity-Check (S-LDPC) Codes
7.1 Introduction
A Low-Density-Parity-Check (LDPC) code is a linear block code defined by its parity-check matrix.
In this specification, we use a special case of LDPC codes, called structured LDPC (S-LDPC) codes,
which have an efficient encoding algorithm and adopted as an FEC code in standardizations such as
IEEE 802.16e and 801.11n.
In this document, we use the following notations.
— K: number of source symbols in a source symbol block
4 © ISO/IEC 2015 – All rights reserved
---------------------- Page: 9 ----------------------
ISO/IEC 23008-10:2015(E)
— K’: number of source symbols in an extended source symbol block
— P: number of repair symbols in a repair symbol block
— P’: number of repair symbols in an extended repair symbol block
— S(i): the i-th source symbol in a source symbol block (0 ≤ i < K). It can be represented as a binary
8
column vector of length 8T or a column vector of length T over GF(2 )
— R(i): the i-th repair symbols in a repair symbol block (0 ≤ i < P). It can be represented as a binary
8
column vector of length 8T or a column vector of length T over GF(2 )
— H: a sparse parity-check matrix of an S-LDPC code.
7.2 Structured LDPC Codes
In this clause, S-LDPC codes are described by parity-check matrices which consist of circulant
permutation matrices or the zero matrix.
Let Q be the L × L permutation matrix given by
01 00
00 10
Q =
000 1
10 00
i
Note that Q is just the circulant permutation matrix which shifts the identity matrix I to the right by i
∞
times for any integer i, 0 ≤ i < L. For simple notation, Q denotes the zero matrix.
Let H be the P’ by K’ + P’ matrix defined by
aa aa
02,,kp+− 01kp+−
00,,01
QQ QQ
aa
aa
10,,11 12,,kp+− 1kp+ −−1
QQ QQ
H =
aa aa
pp−−10,,11 pk−+12,,pp−−11kp+−
QQ QQ
where p and k are given by p = P’ / L and k = K’ / L, respectively and a ∈ {0, 1, …, L–1, ∞}. If the locations
i,j
of 1’s in the first row of the i-th row block
a
a
i,0 ik, +−p 1
H = QQ
i
are fixed, then the locations of other 1’s in H are uniquely determined.
i
7.3 Creating Parity-Check Matrix
For efficient encoding, it restricts the parity part of H to an almost lower triangular matrix with
additional constraints as follows:
HH= H
[]
IP
QI 00 0
00II 0
00I 0
= HI
I
I 0
00 0 II
QI00 0
© ISO/IEC 2015 – All rights reserved 5
---------------------- Page: 10 ----------------------
ISO/IEC 23008-10:2015(E)
In the first column block of H , I is placed only at the ceil(p/2)-th row block , H , where ceil(x) is
P ceil(p/2)–1
the smallest integer not less than x.
Let BM be a mother matrix having 400 column blocks and 20 row blocks with L = 16, i.e. the matrix BM
has 6400 columns and 320 rows. Each column block and row block of BM has exactly 7 and 140 circulant
permutation matrices of size 16, respectively. The remaining part of BM is filled with zero matrices of
size 16. The i-th row block of BM can be represented as a sequence of pairs (t , e ) where t is the index
i,j i,j i,j
of column block corresponding to the j-th circulant permutation matrix and e is its exponent. The BM
i,j
matrix supports various values of K and P with techniques called scaling down and row splitting. The
resulting matrix is used as H for encoding process.
I
In order to support short source symbol blocks efficiently, the matrix BM is scaled down by a scaling
factor S . The resulting matrix is composed of circulant permutation matrices and zero matrices of size
1
a
16/S , i.e. it has 6400/S columns and 320/S rows. The scaling factor can be obtained as S = 2 where
1 1 1 1
a
a is the largest integer satisfying K ≤ (400 ∙ 16) / 2 . Note that the resulting matrix can be represented
as the sequence of pairs (t , e mod (16/S )) since the size of circulant permutation matrices and zero
i,j i,j 1
matrices are reduced from 16 to 16/S .
1
As mentioned above, the matrix BM has 320/S rows after downscaling. It means that the number of
1
repair symbols P is 320/S at maximum. To support larger values of P, we extend the matrix BM by
1
splitting its rows. In this process, each row block is splitted into S row blocks. For given repair symbol
2
block length P and the scaling factor S , the row splitting factor S can be obtained as S = ceil(P/(320/S )).
1 2 2 1
The matrix H is obtained from the matrix BM as follows. Let BM = {(t , e ), (t , e ),…, (t , e )} be
I i i,0 i,0 i,1 i,1 i,139 i,139
the ordered sequence of pairs (t , e ) representing the i-th row block of BM. Let S and S be the scaling
i,j i,j 1 2
factor and the row splitting factor, respectively. They are determined uniquely by K and P. Then the (S
2
× i + j)-th row block of H can be represented as follows:
I
T = {(t , e mod (16/S )) | k mod (S = (S – 1 – j), 0 ≤ k < 140}
(S2×i)+j i,k i,k 1 2) 2
Note that the matrix H has 400 column blocks and S ×20 row blocks with L = 16/S , i.e., it has (6400/S )
I 2 1 1
columns and (S ×320/S ) rows.
2 1
Finally, the parity-check matrix H is obtained by augmenting the matrix H with appropriate size to the
P
matrix H . H has 400 + S ×20 column blocks and S ×20 row blocks with L = 16/S , i.e. H consists of (6400
I 2 2 1
+ S ∙320)/S columns and (S ∙320/S ) rows.
2 1 2 1
7.4 Encoding Algorithm
The encoding of an S-LDPC code is performed based on the following p’×L’ by (k’+p’)×L’ parity-check matrix:
HH= H
[]
IP
QI 00 0
00II 0
00I 0
= HI
I
I 0
00 0 II
QI00 0
where L’ = 16/S , p’ = S ×20 and k’ = 400. It has P’ = S ×320/S rows.
1 2 2 1
The H is divided into the form
AB T
H =
CD E
where A is (p’ – 1)×L by k’×L, B is (p’ – 1)×L by L, T is (p’ – 1)×L by (p’ – 1)×L, C is L by k’×L, D = Q is L by
T T
L and E is L by (p’ – 1)×L. Let c = (s, r , r ) be a codeword specified by H, that is Hc = 0 where s is the
1 2
systematic part, p and p are the parity parts which have length L and (p’ – 1)×L, respectively. That is s
1 2
6 © ISO/IEC 2015 – All rights reserved
---------------------- Page: 11 ----------------------
ISO/IEC 23008-10:2015(E)
= [S(0),…, S(K’–1)], r = [R(0),…, R(L–1)] and r = [R(L),…, R(P’–1)]. Note that S(K), S(K+1) ,…, S(K’–1) denote
1 2
K’–K padded source symbols, which are set to all zero bits and not delivered. Furthermore, R(P),…, R(P’–
1) denote the repair symbols to be punctured, i.e. their values are calculated but not contained in the
corresponding repair symbol block.
Then, the detailed operations for encoding of an S-LDPC code defined by H are as follows:
Therefore, when a source symbol block s is input, this FEC code shall output the repair symbol block
T T
[R(0),…,R(P-1)] of c which satisfies the equation Hc = 0 .
7.5 Decoding Algorithm
S-LDPC codes are one family of LDPC codes. Therefore any decoding algorithm for conventional LDPC
codes can be applied without any modification. Consideration on the decoding algorithm of LDPC codes
can be found in IETF RFC5170.
7.6 Base matrix
The S-LDPC codes can be fully described by the base matrix BM and algorithms to calculate the scaling
factor and the row splitting factor. The i-th row block of BM can be represented as a sequence of pairs
T = {(t , e ), (t , e ),…, (t , e )} where t is the index of column block corresponding to the j-th
i i,0 i,0 i,1 i,1 i,139 i,139 i,j
circulant permutation matrix and e is its exponent for 0 ≤ j < 140.
i,j
T = {(1,8), (2,8), (3,10), (5,12), (6,8), (7,12), (9,8), (12,4), (14,12), (15,0), (19,0), (20,9), (26,4), (34,8),
0
(35,1), (38,0), (45,13), (46,0), (48,13), (56,9), (57,3), (62,1), (63,8), (71,12), (75,8), (77,3), (78,2), (82,13),
(83,13), (85,9), (88,1), (90,15), (92,4), (93,12), (97,0), (99,15), (104,5), (107,14), (110,13), (111,15), (116,9),
(117,7), (120,9), (121,8), (125,15), (127,14), (128,15), (129,9), (131,5), (134,12), (150,12), (152,13), (156,1),
(158,9), (159,13), (161,7), (163,5), (164,4), (165,13), (168,11), (171,9), (172,12), (175,12), (177,13), (180,5),
(185,9), (193,1), (194,8), (195,9), (199,3), (200,9), (202,9), (204,3), (207,13), (212,13), (213,1), (214,13),
(217,3), (223,13), (224,14), (226,10), (227,5), (228,7), (232,5), (236,14), (240,7), (241,7), (245,9), (250,12),
(251,5), (255,5), (260,5), (267,4), (268,4), (272,4), (273,4), (275,9), (276,6), (278,5), (284,8), (288,1),
(289,6), (291,2), (292,4), (297,12), (299,4), (302,4), (309,5), (310,4), (311,3), (312,5), (326,0), (330,10),
(334,9), (335,4), (337,1), (338,6), (340,14), (342,10), (343,1), (347,4), (349,9), (350,1), (351,4), (357,14),
(361,8), (364,0), (365,12), (367,6), (369,2), (373,4), (375,12), (376,12), (377,0), (379,0), (383,0), (384,1),
(388,4), (389,0), (391,3)}
T = {(2,4), (5,0), (8,9), (10,8), (12,8), (13,4), (14,8), (17,1), (23,12), (24,13), (29,9), (30,12), (33,9), (37,4),
1
(45,0), (46,12), (47,8), (56,4), (60,0), (65,13), (73,13), (77,13), (78,12), (81,13), (89,12), (94,5), (99,5),
(100,9), (102,9), (107,4), (111,5), (112,13), (117,4), (125,0), (127,12), (128,5), (133,12), (134,1), (136,1),
(137,0), (138,12), (141,12), (143,4), (155,0), (157,12), (158,9), (160,0), (161,0), (163,8), (169,9), (170,12),
(174,8), (176,4), (177,4), (178,8), (180,8), (182,8), (186,12), (187,8), (188,8), (189,8), (191,8), (192,1),
(196,0), (198,8), (199,8), (200,0), (202,1), (204,4), (207,8), (210,1), (214,4), (217,2), (221,9), (224,0),
(226,12), (228,9), (233,1), (236,8), (239,0), (241,0), (246,1), (249,1), (251,5), (256,8), (257,9), (259,9),
(263,0), (264,1), (266,0), (267,1), (270,5), (271,9), (280,8), (282,0), (285,12), (286,1), (291,0), (292,8),
(295,5), (302,12), (305,12), (306,9), (308,5), (309,4), (311,1), (312,13), (315,13), (316,1), (321,12), (322,5),
(323,1), (324,5), (327,13), (328,5), (338,1), (342,12), (343,5), (346,13), (347,5), (349,0), (356,13), (361,1),
(363,5), (367,5), (369,5), (372,5), (373,13), (374,4), (376,1), (380,4), (382,1), (387,5)
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.