IEC 61937-11:2010

IEC 61937-11 ®
Edition 1.1 2018-11
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
colour
inside
Digital audio – Interface for non-linear PCM encoded audio bitstreams applying
IEC 60958 –
Part 11: MPEG-4 AAC and its extensions in LATM/LOAS

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form

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International Standards for all electrical, electronic and related technologies.

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IEC 61937-11 ®
Edition 1.1 2018-11
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
colour
inside
Digital audio – Interface for non-linear PCM encoded audio bitstreams applying

IEC 60958 –
Part 11: MPEG-4 AAC and its extensions in LATM/LOAS

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.160.30; 33.170 ISBN 978-2-8322-6217-7

IEC 61937-11 ®
Edition 1.1 2018-11
CONSOLIDATED VERSION
REDLINE VERSION
colour
inside
Digital audio – Interface for non-linear PCM encoded audio bitstreams applying
IEC 60958 –
Part 11: MPEG-4 AAC and its extensions in LATM/LOAS

– 2 – IEC 61937-11:2010+AMD1:2018 CSV

 IEC 2018
CONTENTS
FOREWORD . 3

INTRODUCTION . 5

INTRODUCTION to Amendment 1 . 5

1 Scope . 6

2 Normative references . 6

3 Terms, definitions and abbreviations . 6

3.1 Terms and definitions . 6
3.2 Abbreviations . 8
4 Mapping of the audio bit stream on to IEC 61937-1 . 8
4.1 General . 8
4.2 Burst-info for MPEG-4 AAC and its extensions in LATM/LOAS . 8
5 Format of data-burst for MPEG-4 AAC and its extensions in LATM/LOAS . 9
5.1 General . 9
5.2 Pause data-bursts for MPEG-4 AAC and its extensions in LATM/LOAS . 9
5.3 Audio data-bursts . 10
5.3.1 MPEG-4 AAC and its extensions in LATM/LOAS . 10
5.3.2 LATM/LOAS framing . 12
5.3.3 Latency . 12
Annex A (informative) Calculation of delay and data-burst repetition rates – guidelines . 14
Annex B (normative) High-speed transmission . 16
Bibliography . 17

Figure 1 – Data-burst structure . 10
Figure 2 – Latency diagram for burst reception and decoding . 13

Table 1 – Values for data-type bits 0-4 and sub-data-type data-type bits 5-6 . 9
Table 2 – Repetition period of pause data-bursts . 9
Table 3 – Data-type-dependent information . 11
Table A.1 – Examples – Calculation of delay and data-burst repetition rates . 14
Table B.1 – Indication fields . 16

Table B.2 – Signalling example . 16

 IEC 2018
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
DIGITAL AUDIO –
INTERFACE FOR NON-LINEAR PCM ENCODED

AUDIO BITSTREAMS APPLYING IEC 60958 –

Part 11: MPEG-4 AAC and its extensions in LATM/LOAS

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
This consolidated version of the official IEC Standard and its amendment has been prepared
for user convenience.
IEC 61937-11 edition 1.1 contains the first edition (2010-05) [documents 100/1491/CDV and
100/1580/RVC] and its amendment 1 (2018-11) [documents 100/2948/CDV and 100/3033/RVC].
In this Redline version, a vertical line in the margin shows where the technical content is
modified by amendment 1. Additions are in green text, deletions are in strikethrough red text. A
separate Final version with all changes accepted is available in this publication.

– 4 – IEC 61937-11:2010+AMD1:2018 CSV

 IEC 2018
International Standard IEC 61937-11 has been prepared by technical area 4: Digital system
interfaces and protocols, of IEC technical committee 100: Audio, video and multimedia
systems and equipment.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts of IEC 61937, under the general title Digital audio – Interface for non-linear
PCM encoded audio bitstreams applying IEC 60958 can be found on the IEC website.

The committee has decided that the contents of the base publication and its amendment
will remain unchanged until the stability date indicated on the IEC web site
under "http://webstore.iec.ch" in the data related to the specific publication. At this
date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
 IEC 2018
INTRODUCTION
Modern digital video broadcasting standards such as DVB include support for the MPEG-4

HE AAC and/or HE AAC v2 audio codecs as specified in ISO/IEC 14496-3. An increasing

number of countries are adopting these new codecs for their standard definition and high

definition digital video broadcasting services and have started with implementations.

For MPEG-2 AAC audio (ISO/IEC 13818-7) the specified framing format for the audio bit

stream is ADTS and its transport over an IEC 60958 interface is specified in IEC 61937-6.

However, the MPEG-4 (ISO/IEC 14496-3) audio codecs introduce new features and

capabilities that require a framing format that supports more flexible signaling and delivery
mechanisms. Therefore, MPEG-2 Systems (ISO/IEC 13818-1) specifies the MPEG-4
LATM/LOAS framing format for MPEG-4 audio codecs to overcome the limitations of ADTS.
In order to be able to pass the MPEG-4 audio bit stream from a Set Top Box to an A/V
receiver connected via the IEC 60958 interface without needing to reframe the audio bit
stream within ADTS, the MPEG-4 LATM/LOAS framing format needs to be supported by
IEC 61937.
INTRODUCTION to Amendment 1
The revision of IEC 61937-11:2010 has become necessary to specify the protocol where the
interface does not carry an embedded sampling frequency clock. The purpose is primarily to
support stereophonic multichannel audio applications increasing their channel counts. It is
justified in that ARIB introduces 22.2/7.1 audio channel applications, as given in ITU-R
BS.2051-0, into the market in 2018. This Amendment 1 contains the following significant
technical
...

IEC 61937-11 ®
Edition 1.0 2010-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Digital audio – Interface for non-linear PCM encoded audio bitstreams applying
IEC 60958 –
Part 11: MPEG-4 AAC and its extensions in LATM/LOAS

Audionumérique – Interface pour les flux de bits audio à codage MIC non
linéaire conformément à la CEI 60958 –
Partie 11: MPEG-4 AAC et ses extensions en LATM/LOAS

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by
any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IEC or
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About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.
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IEC 61937-11 ®
Edition 1.0 2010-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Digital audio – Interface for non-linear PCM encoded audio bitstreams applying
IEC 60958 –
Part 11: MPEG-4 AAC and its extensions in LATM/LOAS

Audionumérique – Interface pour les flux de bits audio à codage MIC non linéaire
conformément à la CEI 60958 –
Partie 11: MPEG-4 AAC et ses extensions en LATM/LOAS

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX P
ICS 33.160.30; 33.170 ISBN 978-2-88912-321-6
– 2 – 61937-11  IEC:2010
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and abbreviations . 6
3.1 Terms and definitions . 6
3.2 Abbreviations . 8
4 Mapping of the audio bit stream on to IEC 61937-1 . 8
4.1 General . 8
4.2 Burst-info for MPEG-4 AAC and its extensions in LATM/LOAS . 8
5 Format of data-burst for MPEG-4 AAC and its extensions in LATM/LOAS . 9
5.1 General . 9
5.2 Pause data-bursts for MPEG-4 AAC and its extensions in LATM/LOAS . 9
5.3 Audio data-bursts . 10
5.3.1 MPEG-4 AAC and its extensions in LATM/LOAS . 10
5.3.2 LATM/LOAS framing . 12
5.3.3 Latency . 12
Annex A (informative) Calculation of delay and data-burst repetition rates – guidelines . 14
Bibliography . 16

Figure 1 – Data-burst structure . 10
Figure 2 – Latency diagram for burst reception and decoding . 13

Table 1 – Values for data-type and sub-data-type . 9
Table 2 – Repetition period of pause data-bursts . 9
Table 3 – Data-type-dependent information . 11
Table A.1 – Examples – Calculation of delay and data-burst repetition rates . 14

61937-11  IEC:2010 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
DIGITAL AUDIO –
INTERFACE FOR NON-LINEAR PCM ENCODED
AUDIO BITSTREAMS APPLYING IEC 60958 –

Part 11: MPEG-4 AAC and its extensions in LATM/LOAS

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61937-11 has been prepared by technical area 4: Digital system
interfaces and protocols, of IEC technical committee 100: Audio, video and multimedia
systems and equipment.
This bilingual version, published in 2011-02, corresponds to the English version.
The text of this standard is based on the following documents:
CDV Report on voting
100/1491/CDV 100/1580/RVC
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.

– 4 – 61937-11  IEC:2010
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of IEC 61937, under the general title Digital audio – Interface for non-linear
PCM encoded audio bitstreams applying IEC 60958 can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
61937-11  IEC:2010 – 5 –
INTRODUCTION
Modern digital video broadcasting standards such as DVB include support for the MPEG-4
HE AAC and/or HE AAC v2 audio codecs as specified in ISO/IEC 14496-3. An increasing
number of countries are adopting these new codecs for their standard definition and high
definition digital video broadcasting services and have started with implementations.
For MPEG-2 AAC audio (ISO/IEC 13818-7) the specified framing format for the audio bit
stream is ADTS and its transport over an IEC 60958 interface is specified in IEC 61937-6.
However, the MPEG-4 (ISO/IEC 14496-3) audio codecs introduce new features and
capabilities that require a framing format that supports more flexible signaling and delivery
mechanisms. Therefore, MPEG-2 Systems (ISO/IEC 13818-1) specifies the MPEG-4
LATM/LOAS framing format for MPEG-4 audio codecs to overcome the limitations of ADTS.
In order to be able to pass the MPEG-4 audio bit stream from a Set Top Box to an A/V
receiver connected via the IEC 60958 interface without needing to reframe the audio bit
stream within ADTS, the MPEG-4 LATM/LOAS framing format needs to be supported by
IEC 61937.
– 6 – 61937-11  IEC:2010
DIGITAL AUDIO –
INTERFACE FOR NON-LINEAR PCM ENCODED
AUDIO BITSTREAMS APPLYING IEC 609
...