File format for professional transfer and exchange of digital audio data

IEC 62942:2019 specifies a file format for interchanging audio data between compliant equipment. It is primarily intended for audio applications in professional recording, production, post-production, and archiving.
It is derived from the AES31-2 [2] but is also compatible with variant specifications including EBU Tech 3285 [3] to [10], ITU-R BR.1352-3-2007 [11] to [14], and the Japan Post Production Association's BWF-J [15].
This document contains the specification of the broadcast audio extension chunk and its use with PCM-coded audio data. Basic information on the RIFF format and how it can be extended to other types of audio data is given in Annex E. Details of the PCM WAVE format are also given in Annex A.
An optional extended format, BWF-E, supports 64-bit addressing to permit file sizes greater than 4 GB.

Format de fichier pour le transfert et l'échange professionnels de données audionumériques

L'IEC 62942:2019 spécifie un format de fichier qui permet d'échanger des données audio entre des équipements conformes. Il vise principalement les applications audio en ce qui concerne l'enregistrement, la production, la postproduction et l'archivage professionnels.
Il est obtenu à partir de l'AES31-2, mais est également compatible avec des spécifications proches, notamment l'EBU Tech 3285, l'ITU-R BR.1352-3-2007, et le BWF-J de la Japan Post Production Association.
Le présent document contient la spécification du fragment d'extension audio pour diffusion et de son utilisation avec des données audio codées MIC. Des informations de base sur le format RIFF et sur la façon dont il peut être étendu à d'autres types de données audio sont données à l'Annexe E. Des détails sur le format WAVE MIC sont également donnés à l'Annexe A.
Un format étendu facultatif, BWF-E, prend en charge l'adressage 64 bits pour permettre l'utilisation de fichiers dont la taille est supérieure à 4 Go.

General Information

Status
Published
Publication Date
11-Dec-2019
Current Stage
PPUB - Publication issued
Completion Date
12-Dec-2019
Ref Project

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IEC 62942
Edition 1.0 2019-12
INTERNATIONAL
STANDARD
File format for professional transfer and exchange of digital audio data
IEC 62942:2019-12(en)
---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyright © 2019 IEC, Geneva, Switzerland

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

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copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or

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3, rue de Varembé info@iec.ch
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International Standards for all electrical, electronic and related technologies.
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Centre: sales@iec.ch.
---------------------- Page: 2 ----------------------
IEC 62942
Edition 1.0 2019-12
INTERNATIONAL
STANDARD
File format for professional transfer and exchange of digital audio data
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.160.30 ISBN 978-2-8322-7722-5

Warning! Make sure that you obtained this publication from an authorized distributor.

® Registered trademark of the International Electrotechnical Commission
---------------------- Page: 3 ----------------------
– 2 – IEC 62942:2019 © IEC 2019
CONTENTS

FOREWORD ........................................................................................................................... 5

INTRODUCTION ..................................................................................................................... 7

1 Scope .............................................................................................................................. 8

2 Normative references ...................................................................................................... 8

3 Terms and definitions ...................................................................................................... 8

4 BWF file ........................................................................................................................ 10

4.1 Existing chunks defined as part of the RIFF Format .............................................. 10

4.2 Additional chunks .................................................................................................. 10

4.3 Contents of a BWFF .............................................................................................. 10

4.4 Broadcast audio extension chunk .......................................................................... 11

4.5 Filename ............................................................................................................... 13

4.6 Channel usage ...................................................................................................... 13

4.7 File size ................................................................................................................ 13

Annex A (normative) RIFF WAVE file format ........................................................................ 14

A.1 General ................................................................................................................. 14

A.2 Resource Interchange File Format (RIFF) ............................................................. 14

A.2.1 General ......................................................................................................... 14

A.2.2 Chunks .......................................................................................................... 14

A.2.3 RIFF forms .................................................................................................... 15

A.3 Waveform audio file format (WAVE) ...................................................................... 15

A.3.1 General ......................................................................................................... 15

A.3.2 WAVE format chunk ....................................................................................... 16

A.3.3 WAVE format categories ................................................................................ 16

A.4 Storage of WAVE data .......................................................................................... 19

Annex B (normative) Chunk order ........................................................................................ 20

Annex C (normative) Filename conventions ......................................................................... 21

C.1 General ................................................................................................................. 21

C.2 File-name length ................................................................................................... 21

C.3 File-name extension .............................................................................................. 21

C.4 File-name character set ........................................................................................ 21

Annex D (informative) Multi-channel usage .......................................................................... 23

D.1 General ................................................................................................................. 23

D.2 Multi-channel audio data packing .......................................................................... 23

D.3 Channel assignments in multi-channel files ........................................................... 24

D.3.1 General ......................................................................................................... 24

D.3.2 Distribution and archive ................................................................................. 24

D.3.3 Production recordings .................................................................................... 24

Annex E (informative) Other audio codings .......................................................................... 25

E.1 General ................................................................................................................. 25

E.2 MPEG files ............................................................................................................ 25

Annex F (normative) Extended file format (BWF-E) .............................................................. 26

F.1 General ................................................................................................................. 26

F.2 Exceeding the 4-GB limit ....................................................................................... 26

F.2.1 General ......................................................................................................... 26

F.2.2 64-bit resource interchange file format (RF64) ............................................... 27

---------------------- Page: 4 ----------------------
IEC 62942:2019 © IEC 2019 – 3 –

F.3 Compatibility between BWF and BWF-E ................................................................ 28

F.3.1 General ......................................................................................................... 28

F.3.2 Initialisation as BWF ...................................................................................... 28

F.3.3 Transition to BWF-E ...................................................................................... 28

F.4 RIFF/WAVE and RF64/WAVE structures ............................................................... 29

F.4.1 Chunks and structs specific to the RIFF/WAVE format ................................... 29

F.4.2 Chunks and structs specific to the RF64/WAVE (BWF-E) format .................... 29

Annex G (normative) bext chunk versions ............................................................................ 31

G.1 Version 0 .............................................................................................................. 31

G.2 Version 1 .............................................................................................................. 31

G.3 Version 2 .............................................................................................................. 31

Annex H (normative) Loudness parameters.......................................................................... 32

H.1 Treatment of loudness parameters ........................................................................ 32

H.2 Loudness parameter references ............................................................................ 33

Annex I (informative) Definition of the format for "Unique" Source Identifier (USID) for

use in the field .................................................................................. 34

I.1 USID ..................................................................................................................... 34

I.2 Examples of USIDs ............................................................................................... 34

Annex J (informative) Specification of the format for field .......................... 35

J.1 General ................................................................................................................. 35

J.2 Syntax .................................................................................................................. 35

J.3 Examples of coding history fields .......................................................................... 35

Annex K (normative) Universal broadcast audio extension chunk ......................................... 37

K.1 General ................................................................................................................. 37

K.2 Contents of a BWFF with 'ubxt' chunk ................................................................... 37

K.3 Universal broadcast audio extension chunk ........................................................... 37

Bibliography .......................................................................................................................... 40

Figure D.1 – Data packing for 24-bit mono PCM audio data .................................................. 23

Figure D.2 – Data packing for 16-bit stereo (2-channel) PCM audio data .............................. 23

Figure D.3 – Data packing for 24-bit, 4-channel PCM audio data .......................................... 23

Figure D.4 – 24-bit sample packing ....................................................................................... 24

Figure F.1 – Conventional RIFF/WAVE format ...................................................................... 26

Figure F.2 – Extended RF64/WAVE format ........................................................................... 27

Figure F.3 – Compatible RIFF/WAVE structure ..................................................................... 28

Table 1 – bext field content definitions .................................................................................. 12

Table A.1 – Chunk description .............................................................................................. 14

Table A.2 – Format chunk – Common fields .......................................................................... 16

Table A.3 – WAVE format categories .................................................................................... 17

Table A.4 – Data packing for 16-bit mono PCM ..................................................................... 17

Table A.5 – Data packing for 16-bit stereo PCM .................................................................... 18

Table A.6 – PCM data format ................................................................................................ 18

Table A.7 – PCM data format – 16-bit ................................................................................... 18

Table A.8 – PCM WAVE format chunk examples ................................................................... 18

Table C.1 – Permitted file-name characters .......................................................................... 21

---------------------- Page: 5 ----------------------
– 4 – IEC 62942:2019 © IEC 2019

Table C.2 – Non-permitted file-name characters ................................................................... 22

Table C.3 – Non-permitted file-name terminators .................................................................. 22

Table H.1 – Rounding negative values .................................................................................. 32

Table H.2 – Rounding positive values ................................................................................... 32

Table J.1 – CodingHistory parameters .................................................................................. 35

Table K.1 – ubxt field content definitions ............................................................................. 38

---------------------- Page: 6 ----------------------
IEC 62942:2019 © IEC 2019 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FILE FORMAT FOR PROFESSIONAL TRANSFER AND
EXCHANGE OF DIGITAL AUDIO DATA
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 62942 has been prepared by technical area 6: Storage media,

storage data structures, storage systems and equipment, of IEC technical committee 100:

Audio, video and multimedia systems and equipment.
The text of this standard is based on the following documents:
CDV Report on voting
100/3143/CDV 100/3226/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.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

---------------------- Page: 7 ----------------------
– 6 – IEC 62942:2019 © IEC 2019

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.
A bilingual version of this publication may be issued at a later date.
---------------------- Page: 8 ----------------------
IEC 62942:2019 © IEC 2019 – 7 –
INTRODUCTION

The Broadcast Wave format file (BWFF) is based on the Microsoft WAVE audio file format,

which is a type of file specified in the Microsoft resource interchange file format (RIFF) [1]

WAVE files specifically contain audio data. The basic building block of a RIFF file is a chunk

which contains specific information, an identification field, and a size field. A RIFF file

contains a number of chunks.

The BWFF specifically includes a chunk to carry certain

metadata important for broadcast and professional use. For reliable interchange, some

restrictions apply to the format of the audio data.

The Broadcast Wave Format was first developed using ASCII text for all fields. Later, as the

format was further developed, it was proposed to use multi-byte characters to internationalize

the format. It was understood that to use multi-byte character sets within the existing format

would cause compatibility issues when multi-byte metadata was parsed by applications

expecting ASCII text. The separate nature of human-readable and machine-readable
metadata was established, and a new "universal" chunk was established to carry

internationalized human-readable metadata using multi-byte character sets without

interoperability issues. This is described in Annex K.
——————

Microsoft® is a registered trademark, and Windows™ is a trademark of Microsoft Corp.. This information is

given for the convenience of users of this document and does not constitute an endorsement by IEC of the

product named. Equivalent products may be used if they can be shown to lead to the same results.

Numbers in square brackets refer to the Bibliography.
---------------------- Page: 9 ----------------------
– 8 – IEC 62942:2019 © IEC 2019
FILE FORMAT FOR PROFESSIONAL TRANSFER AND
EXCHANGE OF DIGITAL AUDIO DATA
1 Scope

This document specifies a file format for interchanging audio data between compliant

equipment. It is primarily intended for audio applications in professional recording, production,

post-production, and archiving.

It is derived from the AES31-2 [2] but is also compatible with variant specifications including

EBU Tech 3285 [3] to [10], ITU-R BR.1352-3-2007 [11] to [14], and the Japan Post Production

Association's BWF-J [15].

This document contains the specification of the broadcast audio extension chunk and its use

with PCM-coded audio data. Basic information on the RIFF format and how it can be extended

to other types of audio data is given in Annex E. Details of the PCM WAVE format are also

given in Annex A.

An optional extended format, BWF-E, supports 64-bit addressing to permit file sizes greater

than 4 GB.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their

content constitutes requirements of this document. For dated references, only the edition

cited applies. For undated references, the latest edition of the referenced document (including

any amendments) applies.
ISO/IEC 10646:2017, Information technology – Universal Coded Character Set (UCS)
ISO 8601, Data elements and interchange formats – Information interchange –
Representation of dates and times

SMPTE ST 330-2011; SMPTE standard for television – Unique Material Identifier (UMID)

INTERNET ENGINEERING TASK FORCE (IETF). RFC 3629: UTF-8, a transformation format

of ISO 10646 [online]. Edited by F. Yergeau. November 2003 [viewed 2019-11-26]. Available

at https://www.rfc-editor.org/rfc/rfc3629.txt
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
---------------------- Page: 10 ----------------------
IEC 62942:2019 © IEC 2019 – 9 –
3.1
resource interchange file format
RIFF
file representation upon which the WAVE file format is based
3.2
chunk
data package within RIFF files containing related data
3.3
ASCII
7-bit character code compliant with ISO/IEC 646
3.4
waveform audio file format
WAVE
audio file format based on the RIFF file structure
3.5
Broadcast Wave format file
BWFF
WAVE file containing the bext chunk as described in this document
3.6
broadcast extension chunk
bext
extension chunk to WAVE
3.7
universal broadcast audio extension chunk
ubxt
human-readable information of the bext chunk in multi-byte languages
3.8
UMID
unique material identifier as defined in SMPTE ST 330
3.9
Broadcast Wave format, extended
BWF-E

optional extended format that replaces a RIFF header with an RF64 header to support 64-bit

addressing to permit file sizes greater than 4 GB
3.10
RF64
structure equivalent to the RIFF file type supporting 64-bit addressing
3.11
CHAR
8-bit signed integer, representing integer values from −128 to +127
Note 1 to entry: Equivalent C type: "signed char".
3.12
BYTE
8-bit unsigned integer, representing integer values from 0 to 255
Note 1 to entry: Equivalent C type: "unsigned char".
---------------------- Page: 11 ----------------------
– 10 – IEC 62942:2019 © IEC 2019
3.13
INT
16-bit signed integer, representing integer values from −32 768 to +32 767
Note 1 to entry: Equivalent C type: "signed short int".
Note 2 to entry: Multi-byte data types are little-endian.
3.14
WORD
16-bit unsigned integer, representing integer values from 0 to +65 535
Note 1 to entry: Equivalent C type: "unsigned short int".
Note 2 to entry: Multi-byte data types are little-endian.
3.15
LONG

32-bit signed integer, representing integer values from −2 147 483 648 to +2 147 483 647

Note 1 to entry: Equivalent C type: "signed long int".
Note 2 to entry: Multi-byte data types are little-endian.
3.16
DWORD
32-bit unsigned integer, representing integer values from 0 to +4 294 967 295
Note 1 to entry: Equivalent C type: "unsigned long int".
Note 2 to entry: Multi-byte data types are little-endian.
4 BWF file
4.1 Existing chunks defined as part of the RIFF Format

This specification uses a number of RIFF chunks which are already defined (see Annex A).

These are:
Format Chunk
Audio data chunk
4.2 Additional chunks

Additional chunks can be present in the file. Some of these can be outside the scope of this

document. Applications may or may not interpret or make use of these chunks, so the integrity

of the data contained in such unknown chunks cannot be guaranteed. However, compliant

applications should pass on unknown chunks with their contents unchanged (but see also

Annex B).
4.3 Contents of a BWFF
A BWFF shall contain the RIFF "WAVE" header and at least the following chunks:

RIFF('WAVE'
/* Format of the audio signal: PCM/MPEG */
/* information on the audio sequence */
) /* sound data */
---------------------- Page: 12 ----------------------
IEC 62942:2019 © IEC 2019 – 11 –
4.4 Broadcast audio extension chunk

Extra parameters needed for exchange of material between broadcasters are added in a

specific broadcast audio extension, or bext chunk. The structure of the bext chunk shall be

defined as follows:
typedef struct chunk_header {
DWORD ckID; /* (broadcastextension)ckID=bext */
DWORD ckSize; /* size of extension chunk */
BYTE ckData[ckSize]; /* data of the chunk */
} CHUNK_HEADER;
typedef struct broadcast_audio_extension {
CHAR Description[256]; /* ASCII: "Description of the sound
sequence" */
CHAR Originator[32]; /* ASCII: "Name of the originator" */
CHAR OriginatorReference[32]; /* ASCII: "Reference of the originator" */
CHAR OriginationDate[10]; /* ASCII: "yyyy-mm-dd" */
CHAR OriginationTime[8]; /* ASCII: "hh:mm:ss" */
DWORD TimeReferenceLow; /* First sample count since midnight, low
word */
DWORD TimeReferenceHigh; /* First sample count since midnight, high
word */
WORD Version; /* Version of the BWF; unsigned binary
number. See Annex G */
BYTE UMID_0; /* Binary byte 0 of SMPTE UMID */
....
BYTE UMID_63; /* Binary byte 63 of SMPTE UMID */
INT LoudnessValue; /* Integrated Loudness Value of the file in
LKFS (multiplied by 100) see Annex H */
INT LoudnessRange; /* Loudness Range of the file in LU
(multiplied by 100), see Annex H */
INT MaxTruePeakLevel; /* Maximum True Peak Level of the file
expressed as dBTP (multiplied by 100), see
Annex H */
INT MaxMomentaryLoudness; /* Highest value of the Momentary Loudness
Level of the file in LKFS (multiplied by
100), see Annex H */
INT MaxShortTermLoudness; /* Highest value of the Short-Term Loudness
Level of the file in LKFS (multiplied by
100), see Annex H */
BYTE Reserved[180]; /* 180 bytes, reserved for future use, set
to "NULL" */
CHAR CodingHistory[]; /* ASCII: « History coding » */
} BROADCAST_EXT

The content of the fields in the bext chunk shall be defined as shown in Table 1. Note that in

applications where ASCII text is inappropriate for human-readable information (for example

when a character set other than ISO 646 is required), it is necessary to carry it by another

means, for example, in a dedicated metadata chunk added to the BWFF. See also Annex K.

All the items except "Description", "Originator", "OriginatorReference" and "CodingHistory"

should have the same content as that of each corresponding item of the ubxt chunk (see

Annex K), if present. If machine-readable data in the "bext" chunk is updated, the

corresponding machine-readable data in the "ubxt" chunk should also be updated identically.

---------------------- Page: 13 ----------------------
– 12 – IEC 62942:2019 © IEC 2019
Table 1 – bext field content definitions
Description
Human ASCII string, 256 characters or fewer, containing a description of the
sequence. If line breaks are used, lines shall be terminated by
. If data is not available or if the length of the string is less
than 256 characters, the first unused character shall be a null character
(00 ).
To help applications that only display a short description, a summary of
the description should be contained in the first 64 characters. The last
192 characters may be used for d
...

IEC 62942
Edition 1.0 2019-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
File format for professional transfer and exchange of digital audio data
Format de fichier pour le transfert et l'échange professionnels de données
audionumériques
IEC 62942:2019-12(en-fr)
---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyright © 2019 IEC, Geneva, Switzerland

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

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IEC Central Office Tel.: +41 22 919 02 11
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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 corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org

The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,

variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English

committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.

and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished

Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary

details all new publications released. Available online and 67 000 electrotechnical terminology entries in English and

once a month by email. French extracted from the Terms and Definitions clause of

IEC publications issued since 2002. Some entries have been

IEC Customer Service Centre - webstore.iec.ch/csc collected from earlier publications of IEC TC 37, 77, 86 and

If you wish to give us your feedback on this publication or CISPR.
need further assistance, please contact the Customer Service
Centre: sales@iec.ch.
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IEC 62942
Edition 1.0 2019-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
File format for professional transfer and exchange of digital audio data
Format de fichier pour le transfert et l'échange professionnels de données
audionumériques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.160.30 ISBN 978-2-8322-8696-8

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
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– 2 – IEC 62942:2019 © IEC 2019
CONTENTS

FOREWORD ........................................................................................................................... 5

INTRODUCTION ..................................................................................................................... 7

1 Scope .............................................................................................................................. 8

2 Normative references ...................................................................................................... 8

3 Terms and definitions ...................................................................................................... 8

4 BWF file ........................................................................................................................ 10

4.1 Existing chunks defined as part of the RIFF Format .............................................. 10

4.2 Additional chunks .................................................................................................. 10

4.3 Contents of a BWFF .............................................................................................. 10

4.4 Broadcast audio extension chunk .......................................................................... 11

4.5 Filename ............................................................................................................... 13

4.6 Channel usage ...................................................................................................... 13

4.7 File size ................................................................................................................ 13

Annex A (normative) RIFF WAVE file format ........................................................................ 14

A.1 General ................................................................................................................. 14

A.2 Resource Interchange File Format (RIFF) ............................................................. 14

A.2.1 General ......................................................................................................... 14

A.2.2 Chunks .......................................................................................................... 14

A.2.3 RIFF forms .................................................................................................... 15

A.3 Waveform audio file format (WAVE) ...................................................................... 15

A.3.1 General ......................................................................................................... 15

A.3.2 WAVE format chunk ....................................................................................... 16

A.3.3 WAVE format categories ................................................................................ 16

A.4 Storage of WAVE data .......................................................................................... 19

Annex B (normative) Chunk order ........................................................................................ 20

Annex C (normative) Filename conventions ......................................................................... 21

C.1 General ................................................................................................................. 21

C.2 File-name length ................................................................................................... 21

C.3 File-name extension .............................................................................................. 21

C.4 File-name character set ........................................................................................ 21

Annex D (informative) Multi-channel usage .......................................................................... 23

D.1 General ................................................................................................................. 23

D.2 Multi-channel audio data packing .......................................................................... 23

D.3 Channel assignments in multi-channel files ........................................................... 24

D.3.1 General ......................................................................................................... 24

D.3.2 Distribution and archive ................................................................................. 24

D.3.3 Production recordings .................................................................................... 24

Annex E (informative) Other audio codings .......................................................................... 25

E.1 General ................................................................................................................. 25

E.2 MPEG files ............................................................................................................ 25

Annex F (normative) Extended file format (BWF-E) .............................................................. 26

F.1 General ................................................................................................................. 26

F.2 Exceeding the 4-GB limit ....................................................................................... 26

F.2.1 General ......................................................................................................... 26

F.2.2 64-bit resource interchange file format (RF64) ............................................... 27

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IEC 62942:2019 © IEC 2019 – 3 –

F.3 Compatibility between BWF and BWF-E ................................................................ 28

F.3.1 General ......................................................................................................... 28

F.3.2 Initialisation as BWF ...................................................................................... 28

F.3.3 Transition to BWF-E ...................................................................................... 28

F.4 RIFF/WAVE and RF64/WAVE structures ............................................................... 29

F.4.1 Chunks and structs specific to the RIFF/WAVE format ................................... 29

F.4.2 Chunks and structs specific to the RF64/WAVE (BWF-E) format .................... 29

Annex G (normative) bext chunk versions ............................................................................ 31

G.1 Version 0 .............................................................................................................. 31

G.2 Version 1 .............................................................................................................. 31

G.3 Version 2 .............................................................................................................. 31

Annex H (normative) Loudness parameters.......................................................................... 32

H.1 Treatment of loudness parameters ........................................................................ 32

H.2 Loudness parameter references ............................................................................ 33

Annex I (informative) Definition of the format for "Unique" Source Identifier (USID) for

use in the field .................................................................................. 34

I.1 USID ..................................................................................................................... 34

I.2 Examples of USIDs ............................................................................................... 34

Annex J (informative) Specification of the format for field .......................... 35

J.1 General ................................................................................................................. 35

J.2 Syntax .................................................................................................................. 35

J.3 Examples of coding history fields .......................................................................... 35

Annex K (normative) Universal broadcast audio extension chunk ......................................... 37

K.1 General ................................................................................................................. 37

K.2 Contents of a BWFF with 'ubxt' chunk ................................................................... 37

K.3 Universal broadcast audio extension chunk ........................................................... 37

Bibliography .......................................................................................................................... 40

Figure D.1 – Data packing for 24-bit mono PCM audio data .................................................. 23

Figure D.2 – Data packing for 16-bit stereo (2-channel) PCM audio data .............................. 23

Figure D.3 – Data packing for 24-bit, 4-channel PCM audio data .......................................... 23

Figure D.4 – 24-bit sample packing ....................................................................................... 24

Figure F.1 – Conventional RIFF/WAVE format ...................................................................... 26

Figure F.2 – Extended RF64/WAVE format ........................................................................... 27

Figure F.3 – Compatible RIFF/WAVE structure ..................................................................... 28

Table 1 – bext field content definitions .................................................................................. 12

Table A.1 – Chunk description .............................................................................................. 14

Table A.2 – Format chunk – Common fields .......................................................................... 16

Table A.3 – WAVE format categories .................................................................................... 17

Table A.4 – Data packing for 16-bit mono PCM ..................................................................... 17

Table A.5 – Data packing for 16-bit stereo PCM .................................................................... 18

Table A.6 – PCM data format ................................................................................................ 18

Table A.7 – PCM data format – 16-bit ................................................................................... 18

Table A.8 – PCM WAVE format chunk examples ................................................................... 18

Table C.1 – Permitted file-name characters .......................................................................... 21

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Table C.2 – Non-permitted file-name characters ................................................................... 22

Table C.3 – Non-permitted file-name terminators .................................................................. 22

Table H.1 – Rounding negative values .................................................................................. 32

Table H.2 – Rounding positive values ................................................................................... 32

Table J.1 – CodingHistory parameters .................................................................................. 35

Table K.1 – ubxt field content definitions ............................................................................. 38

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IEC 62942:2019 © IEC 2019 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FILE FORMAT FOR PROFESSIONAL TRANSFER AND
EXCHANGE OF DIGITAL AUDIO DATA
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 62942 has been prepared by technical area 6: Storage media,

storage data structures, storage systems and equipment, of IEC technical committee 100:

Audio, video and multimedia systems and equipment.
The text of this standard is based on the following documents:
CDV Report on voting
100/3143/CDV 100/3226/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.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

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– 6 – IEC 62942:2019 © IEC 2019

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.
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IEC 62942:2019 © IEC 2019 – 7 –
INTRODUCTION

The Broadcast Wave format file (BWFF) is based on the Microsoft WAVE audio file format,

which is a type of file specified in the Microsoft resource interchange file format (RIFF) [1]

WAVE files specifically contain audio data. The basic building block of a RIFF file is a chunk

which contains specific information, an identification field, and a size field. A RIFF file

contains a number of chunks.

The BWFF specifically includes a chunk to carry certain

metadata important for broadcast and professional use. For reliable interchange, some

restrictions apply to the format of the audio data.

The Broadcast Wave Format was first developed using ASCII text for all fields. Later, as the

format was further developed, it was proposed to use multi-byte characters to internationalize

the format. It was understood that to use multi-byte character sets within the existing format

would cause compatibility issues when multi-byte metadata was parsed by applications

expecting ASCII text. The separate nature of human-readable and machine-readable
metadata was established, and a new "universal" chunk was established to carry

internationalized human-readable metadata using multi-byte character sets without

interoperability issues. This is described in Annex K.
——————

Microsoft® is a registered trademark, and Windows™ is a trademark of Microsoft Corp.. This information is

given for the convenience of users of this document and does not constitute an endorsement by IEC of the

product named. Equivalent products may be used if they can be shown to lead to the same results.

Numbers in square brackets refer to the Bibliography.
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– 8 – IEC 62942:2019 © IEC 2019
FILE FORMAT FOR PROFESSIONAL TRANSFER AND
EXCHANGE OF DIGITAL AUDIO DATA
1 Scope

This document specifies a file format for interchanging audio data between compliant

equipment. It is primarily intended for audio applications in professional recording, production,

post-production, and archiving.

It is derived from the AES31-2 [2] but is also compatible with variant specifications including

EBU Tech 3285 [3] to [10], ITU-R BR.1352-3-2007 [11] to [14], and the Japan Post Production

Association's BWF-J [15].

This document contains the specification of the broadcast audio extension chunk and its use

with PCM-coded audio data. Basic information on the RIFF format and how it can be extended

to other types of audio data is given in Annex E. Details of the PCM WAVE format are also

given in Annex A.

An optional extended format, BWF-E, supports 64-bit addressing to permit file sizes greater

than 4 GB.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their

content constitutes requirements of this document. For dated references, only the edition

cited applies. For undated references, the latest edition of the referenced document (including

any amendments) applies.
ISO/IEC 10646:2017, Information technology – Universal Coded Character Set (UCS)
ISO 8601, Data elements and interchange formats – Information interchange –
Representation of dates and times

SMPTE ST 330-2011; SMPTE standard for television – Unique Material Identifier (UMID)

INTERNET ENGINEERING TASK FORCE (IETF). RFC 3629: UTF-8, a transformation format

of ISO 10646 [online]. Edited by F. Yergeau. November 2003 [viewed 2019-11-26]. Available

at https://www.rfc-editor.org/rfc/rfc3629.txt
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
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IEC 62942:2019 © IEC 2019 – 9 –
3.1
resource interchange file format
RIFF
file representation upon which the WAVE file format is based
3.2
chunk
data package within RIFF files containing related data
3.3
ASCII
7-bit character code compliant with ISO/IEC 646
3.4
waveform audio file format
WAVE
audio file format based on the RIFF file structure
3.5
Broadcast Wave format file
BWFF
WAVE file containing the bext chunk as described in this document
3.6
broadcast extension chunk
bext
extension chunk to WAVE
3.7
universal broadcast audio extension chunk
ubxt
human-readable information of the bext chunk in multi-byte languages
3.8
UMID
unique material identifier as defined in SMPTE ST 330
3.9
Broadcast Wave format, extended
BWF-E

optional extended format that replaces a RIFF header with an RF64 header to support 64-bit

addressing to permit file sizes greater than 4 GB
3.10
RF64
structure equivalent to the RIFF file type supporting 64-bit addressing
3.11
CHAR
8-bit signed integer, representing integer values from −128 to +127
Note 1 to entry: Equivalent C type: "signed char".
3.12
BYTE
8-bit unsigned integer, representing integer values from 0 to 255
Note 1 to entry: Equivalent C type: "unsigned char".
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– 10 – IEC 62942:2019 © IEC 2019
3.13
INT
16-bit signed integer, representing integer values from −32 768 to +32 767
Note 1 to entry: Equivalent C type: "signed short int".
Note 2 to entry: Multi-byte data types are little-endian.
3.14
WORD
16-bit unsigned integer, representing integer values from 0 to +65 535
Note 1 to entry: Equivalent C type: "unsigned short int".
Note 2 to entry: Multi-byte data types are little-endian.
3.15
LONG

32-bit signed integer, representing integer values from −2 147 483 648 to +2 147 483 647

Note 1 to entry: Equivalent C type: "signed long int".
Note 2 to entry: Multi-byte data types are little-endian.
3.16
DWORD
32-bit unsigned integer, representing integer values from 0 to +4 294 967 295
Note 1 to entry: Equivalent C type: "unsigned long int".
Note 2 to entry: Multi-byte data types are little-endian.
4 BWF file
4.1 Existing chunks defined as part of the RIFF Format

This specification uses a number of RIFF chunks which are already defined (see Annex A).

These are:
Format Chunk
Audio data chunk
4.2 Additional chunks

Additional chunks can be present in the file. Some of these can be outside the scope of this

document. Applications may or may not interpret or make use of these chunks, so the integrity

of the data contained in such unknown chunks cannot be guaranteed. However, compliant

applications should pass on unknown chunks with their contents unchanged (but see also

Annex B).
4.3 Contents of a BWFF
A BWFF shall contain the RIFF "WAVE" header and at least the following chunks:

RIFF('WAVE'
/* Format of the audio signal: PCM/MPEG */
/* information on the audio sequence */
) /* sound data */
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IEC 62942:2019 © IEC 2019 – 11 –
4.4 Broadcast audio extension chunk

Extra parameters needed for exchange of material between broadcasters are added in a

specific broadcast audio extension, or bext chunk. The structure of the bext chunk shall be

defined as follows:
typedef struct chunk_header {
DWORD ckID; /* (broadcastextension)ckID=bext */
DWORD ckSize; /* size of extension chunk */
BYTE ckData[ckSize]; /* data of the chunk */
} CHUNK_HEADER;
typedef struct broadcast_audio_extension {
CHAR Description[256]
...

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