IEC 61937-11:2021

Digital audio - Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 - Part 11: MPEG-4 AAC and its extensions and MPEG-D USAC in LATM/LOAS

IEC 61937-11:2021 describes the method to convey non-linear PCM bitstreams encoded in accordance with the MPEG-4 AAC format and its extensions (spectral band replication, parametric stereo and MPEG surround), and non-linear PCM bitstreams encoded in accordance with the MPEG-D USAC format, framed in MPEG-4 LATM/LOAS. IEC 61937-11:2021 cancels and replaces the first edition published in 2010, and Amendment 1:2018. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) MPEG-D USAC has been added.

General Information

• Status: Published
• Publication Date: 14-Jul-2021
• ICS: 33.160.30 - Audio systems
• ICS: 33.170 - Television and radio broadcasting
• Technical Committee: TA 20 - Analogue and digital audio
• Drafting Committee: MT 61937-11 - TC 100/TA 20/MT 61937-11
• Current Stage: PPUB - Publication issued
• Start Date: 29-Jul-2021
• Completion Date: 15-Jul-2021

Relations

• Revises: IEC 61937-11:2010/AMD1:2018 - Amendment 1 - Digital audio - Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 - Part 11: MPEG-4 AAC and its extensions in LATM/LOAS
• Effective Date: 05-Sep-2023
• Revises: IEC 61937-11:2010 - Digital audio - Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 - Part 11: MPEG-4 AAC and its extensions in LATM/LOAS
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61937-11 ®
Edition 2.0 2021-07
INTERNATIONAL
STANDARD
Digital audio – Interface for non-linear PCM encoded audio bitstreams applying
IEC 60958 –
Part 11: MPEG-4 AAC and its extensions and MPEG-D USAC in 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 IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Central Office Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
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 corrigendum or an amendment might have been published.

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details all new publications released. Available online and
and French, with equivalent terms in 18 additional languages.
once a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc

If you wish to give us your feedback on this publication or
need further assistance, please contact the Customer Service
Centre: [e-mail].
IEC 61937-11 ®
Edition 2.0 2021-07
INTERNATIONAL
STANDARD
Digital audio – Interface for non-linear PCM encoded audio bitstreams applying

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

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.160.30; 33.170 ISBN 978-2-8322-9950-0

– 2 – IEC 61937-11:2021 © IEC 2021
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references. 7
3 Terms and definitions . 7
3.1 Terms and definitions . 7
3.2 Abbreviated terms . 9
4 Mapping of the audio bit stream on to IEC 61937-1 . 10
4.1 General . 10
4.2 Burst-info for MPEG-4 AAC and its extensions and MPEG-D USAC in
LATM/LOAS . 10
5 Format of data-burst for MPEG-4 AAC and its extensions and MPEG-D USAC in
LATM/LOAS . 10
5.1 General . 10
5.2 Pause data-bursts for MPEG-4 AAC and its extensions in LATM/LOAS . 11
5.3 Audio data-bursts . 11
5.3.1 MPEG-4 AAC and its extensions in LATM/LOAS . 11
5.3.2 USAC in LATM/LOAS . 13
5.3.3 LATM/LOAS framing . 14
5.3.4 Latency . 15
Annex A (informative)  Calculation of delay and data-burst repetition rates –
guidelines . 16
A.1 Examples . 16
A.2 Guidelines. 17
Annex B (normative)  High-speed transmission . 18
B.1 Indication . 18
B.2 Example. 18
Annex C (informative)  MPEG-4 and MPEG-D audio profiles and audio object types . 19
C.1 Overview. 19
C.2 MPEG-4 AAC Profile . 19
C.3 MPEG-4 High-Efficiency AAC Profile . 19
C.4 MPEG-4 High-Efficiency AAC v2 Profile . 19
C.5 MPEG-D Baseline USAC Profile . 20
C.6 MPEG-D Extended HE-AAC Profile . 20
Bibliography . 21

Figure 1 – Data-burst structure. 11
Figure 2 – Data-burst structure. 13
Figure 3 – Latency diagram for burst reception and decoding . 15
Figure C.1 – MPEG-4 /MPEG-D audio profiles structure . 19

Table 1 – Values for data-type bits 0-4 and data-type bits 5-6 . 10
Table 2 – Repetition period of pause data-bursts . 11
Table 3 – Data-type-dependent information for MPEG-4 AAC audio and its extensions
in LATM/LOAS . 12

Table 4 – Data-type-dependent information for USAC audio in LATM/LOAS . 14
Table A.1 – Examples – Calculation of delay and data-burst repetition rates for
AAC_LC and HE AAC . 16
Table A.2 – Examples – Calculation of delay and data-burst repetition rates for USAC . 17
Table B.1 – Indication fields . 18
Table B.2 – Signalling example . 18

– 4 – IEC 61937-11:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
DIGITAL AUDIO – INTERFACE FOR NON-LINEAR PCM
ENCODED AUDIO BITSTREAMS APPLYING IEC 60958 –

Part 11: MPEG-4 AAC and its extensions
and MPEG-D USAC 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.
IEC 61937-11 has been prepared by technical area 20: Analogue and digital audio, of IEC
technical committee 100: Audio, video and multimedia systems and equipment. It is an
International Standard.
This second edition cancels and replaces the first edition published in 2010, and
Amendment 1:2018. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) MPEG-D USAC has been added.

The text of this International Standard is based on the following documents:
Draft Report on voting
100/3523/CDV 100/3582/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
A list of all parts in the IEC 61937 series, published under the general title Digital audio –
Interface for non-linear PCM encoded audio bitstreams applying IEC 60958, can be found on
the IEC website.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 61937-11:2021 © IEC 2021
INTRODUCTION
Modern digital video broadcasting standards, such as DVB, include support for the MPEG-4
HE AAC and/or HE AAC v2 audio codecs 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
...

IEC 61937-11 ®
Edition 2.0 2021-07
REDLINE 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 and MPEG-D USAC in 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 IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Central Office Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
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 corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC online collection - oc.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews. With a subscription you will always
committee, …). It also gives information on projects, replaced have access to up to date content tailored to your needs.
and withdrawn publications.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 000 terminological entries in English
details all new publications released. Available online and
and French, with equivalent terms in 18 additional languages.
once a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc

If you wish to give us your feedback on this publication or
need further assistance, please contact the Customer Service
Centre: [e-mail].
IEC 61937-11 ®
Edition 2.0 2021-07
REDLINE 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 and MPEG-D USAC in LATM/LOAS
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.160.30; 33.170 ISBN 978-2-8322-5016-7
– 2 – IEC 61937-11:2021 RLV © IEC 2021
CONTENTS
FOREWORD . 4
INTRODUCTION . 2
INTRODUCTION to Amendment 1 .
1 Scope . 7
2 Normative references. 7
3 Terms and definitions . 7
3.1 Terms and definitions . 7
3.2 Abbreviated terms . 9
4 Mapping of the audio bit stream on to IEC 61937-1 . 10
4.1 General . 10
4.2 Burst-info for MPEG-4 AAC and its extensions and MPEG-D USAC in
LATM/LOAS . 10
5 Format of data-burst for MPEG-4 AAC and its extensions and MPEG-D USAC in
LATM/LOAS . 11
5.1 General . 11
5.2 Pause data-bursts for MPEG-4 AAC and its extensions in LATM/LOAS . 11
5.3 Audio data-bursts . 11
5.3.1 MPEG-4 AAC and its extensions in LATM/LOAS . 11
5.3.2 USAC in LATM/LOAS . 13
5.3.3 LATM/LOAS framing . 13
5.3.4 Latency . 15
Annex A (informative)  Calculation of delay and data-burst repetition rates –
guidelines . 17
A.1 Examples . 17
A.2 Guidelines. 18
Annex B (normative)  High-speed transmission . 19
B.1 Indication . 19
B.2 Example. 19
Annex C (informative)  MPEG-4 and MPEG-D audio profiles and audio object types . 20
C.1 Overview. 20
C.2 MPEG-4 AAC Profile . 20
C.3 MPEG-4 High-Efficiency AAC Profile . 20
C.4 MPEG-4 High-Efficiency AAC v2 Profile . 20
C.5 MPEG-D Baseline USAC Profile . 21
C.6 MPEG-D Extended HE-AAC Profile . 21
Bibliography . 22

Figure 1 – Data-burst structure. 12
Figure 2 – Data-burst structure. 14
Figure 3 – Latency diagram for burst reception and decoding . 16
Figure C.1 – MPEG-4 /MPEG-D audio profiles structure . 20

Table 1 – Values for data-type bits 0-4 and data-type bits 5-6 . 10
Table 2 – Repetition period of pause data-bursts . 11

Table 3 – Data-type-dependent information for MPEG-4 AAC audio and its extensions
in LATM/LOAS . 12
Table 4 – Data-type-dependent information for USAC audio in LATM/LOAS . 14
Table A.1 – Examples – Calculation of delay and data-burst repetition rates for
AAC_LC and HE AAC . 17
Table A.2 – Examples – Calculation of delay and data-burst repetition rates for USAC . 18
Table B.1 – Indication fields . 19
Table B.2 – Signalling example . 19

– 4 – IEC 61937-11:2021 RLV © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
DIGITAL AUDIO – INTERFACE FOR NON-LINEAR PCM
ENCODED AUDIO BITSTREAMS APPLYING IEC 60958 –

Part 11: MPEG-4 AAC and its extensions
and MPEG-D USAC 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.
This redline version of the official IEC Standard allows the user to identify the changes made to
the previous edition IEC 61937-11:2010+AMD1:2018 CSV. A vertical bar appears in the margin
wherever a change has been made. Additions are in green text, deletions are in strikethrough
red text.
IEC 61937-11 has been prepared by technical area 20: Analogue and digital audio, of IEC
technical committee 100: Audio, video and multimedia systems and equipment. It is an
International Standard.
This second edition cancels and replaces the first edition published in 2010, and
Amendment 1:2018. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) MPEG-D USAC has been added.
The text of this International Standard is based on the following documents:
Draft Report on voting
100/3523/CDV 100/3582/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
A list of all parts in the IEC 61937 series, published under the general title Digital audio –
Interface for non-linear PCM encoded audio bitstreams applying IEC 60958, can be found on
the IEC website.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates that
...