IEC 61937-2:2003

INTERNATIONAL IEC
STANDARD
61937-2
First edition
2003-05
Digital audio –
Interface for non-linear PCM encoded
audio bitstreams applying IEC 60958 –
Part 2:
Burst-info
Reference number
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INTERNATIONAL IEC
STANDARD
61937-2
First edition
2003-05
Digital audio –
Interface for non-linear PCM encoded
audio bitstreams applying IEC 60958 –
Part 2:
Burst-info
 IEC 2003  Copyright - all rights reserved
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mechanical, including photocopying and microfilm, without permission in writing from the publisher.
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International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue

– 2 – 61937-2  IEC:2003(E)
CONTENTS
FOREWORD . 3

1 Scope . 5

2 Normative references. 5

3 Terms and definitions . 5

3.1 Definitions . 5

3.2 Abbreviations. 7
3.3 Presentation convention . 7
4 Burst-info. 8
4.1 Audio data-bursts . 8
4.1.1 General. 8
4.1.2 AC-3 . 8
4.1.3 MPEG-1 ayer-1 . 8
4.1.4 MPEG-1 layer-2 or -3 or MPEG-2 without extension. 8
4.1.5 MPEG-2 with extension. 8
4.1.6 MPEG-2 AAC. 9
4.1.7 MPEG-2 layer-1 low sampling frequency. 9
4.1.8 MPEG-2 layer-2 low sampling frequency.10
4.1.9 MPEG-2 layer-3 low sampling frequency.10
4.1.10 DTS type I .10
4.1.11 DTS type II .10
4.1.12 DTS type III .10
4.1.13 ATRAC .10
4.1.14 ATRAC 2/3.10
Bibliography.11
Table 1 – Audio data-types . 9

61937-2  IEC:2003(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
DIGITAL AUDIO –
INTERFACE FOR NON-LINEAR PCM ENCODED

AUDIO BITSTREAMS APPLYING IEC 60958 –

Part 2: Burst-info
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61937-2 has been prepared by technical area 4: Digital system
interfaces, of IEC technical committee 100: Audio, video and multimedia systems and
equipment.
This standard cancels and replaces IEC 61937, published in 2000, which has been divided
into four parts (see below). This first edition constitutes a technical revision.
The text of this standard is based on the following documents:

FDIS Report on voting
100/645/FDIS 100/671/RVD
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.

– 4 – 61937-2  IEC:2003(E)
IEC 61937 consists of the following parts under the general title Digital audio – Interface for
non-linear PCM encoded audio bitstreams applying IEC 60958:

Part 1: General
Part 2: Burst-info
Part 3: Non-linear PCM bitstreams according to the AC-3 format

Part 4: Non-linear PCM bistreams according to the MPEG audio formats

Part 5: Non-linear PCM bitstreams according to the DTS (Digital Theatre Systems) format(s)

Part 6: Non-linear PCM bitstreams according to the MPEG-2 AAC format

Part 7: Non-linear PCM bistreams according to the ATRAC and ATRAC2/3 formats
The committee has decided that the contents of this publication will remain unchanged until
October 2005. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
The contents of the corrigendum of March 2004 have been included in this copy.

61937-2  IEC:2003(E) – 5 –
DIGITAL AUDIO –
INTERFACE FOR NON-LINEAR PCM ENCODED

AUDIO BITSTREAMS APPLYING IEC 60958 –

Part 2: Burst-info
1 Scope
IEC 60958 specifies a widely used interface for digital audio equipment with two-channel
linear PCM audio. This part of IEC 61937 describes how the interface is used to convey
non-linear PCM encoded audio streams.
2 Normative references
The following referenced documents are indispensable for the application 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.
IEC 60958 (all parts), Digital audio interface
IEC 61937 (all parts), Digital audio – Interface for non-linear PCM encoded audio bitstreams
applying IEC 60958
ISO/IEC 11172-3:1993, Information technology – Coding of moving pictures and associated
audio for digital storage media at up to about 1,5 Mbit/s – Part 3: Audio
ISO/IEC 13818-3:1998, Information technology – Generic coding of moving pictures and
associated audio information – Part 3: Audio
ISO/IEC 13818-7:1997, Information technology – Generic coding of moving pictures and
associated audio information – Part 7: Advanced Audio Coding (AAC)
ITU-R Recommendation BS.1196-1, Audio coding for digital terrestrial television broadcasting
3 Terms and definitions
3.1 Definitions
3.1.1
audio data-burst
data-burst with an encoded audio frame as burst-payload
3.1.2
audio data-word
16-bit data word
3.1.3
audio frame
fixed number of audio samples
NOTE The number of samples in an audio frame depends on the particular encoding system which is used to
encode the audio frame into the encoded audio frame.

– 6 – 61937-2  IEC:2003(E)
3.1.4
audio gap
period in the sequence of baseband audio samples where valid samples of audio are not

available
3.1.5
bitstream
non-linear PCM encoded audio source, represented in a sequence of bits

NOTE In this interface the bitstream consists of a sequence of data-bursts.

3.1.6
data-burst
packet of data, including the burst-preamble, to be transmitted across the interface
3.1.7
burst-payload
information content of the data-burst
3.1.8
burst-preamble
header for the data-burst, containing synchronization, and information about the data
contained in the burst-payload
3.1.9
data-type
reference to the type of payload of the data-bursts
3.1.10
encoded audio frame
minimum decodable unit of an encoded data sequence
NOTE Each encoded audio frame is the encoded representation of a fixed number of audio samples (for each
original audio channel). The number of samples that are encoded into an encoded audio frame depends on
the particular encoding system which is used to encode the audio frame into the encoded audio frame.
3.1.11
length-code
code indicating the length of the data-burst-payload in bits
3.1.12
repetition period
period between the reference point of the current data-burst, and the reference point of the
immediately following data-burst of the same data-type

3.1.13
sampling frequency
sampling frequency of the encoded PCM audio samples (i.e. before encoding and after
decoding)
3.1.14
sampling period
time period related to the sampling frequency of the PCM audio samples, represented in
the encoded bitstream
3.1.15
stuffing
occupying the unused data capacity of the interface

61937-2  IEC:2003(E) – 7 –
3.1.16
stuffing sub-frame
occupying the unused data capacity in 16-bit audio data words

3.1.17
stream gap
period within the encoded audio bitstream without any audio frame; a discontinuity in the

bitstream
NOTE Typically, a stream gap will occur between encoded audio frames.

3.2 Abbreviations
3.2.1
AAC
Advanced Audio Coding
3.2.2
ATRAC
Adaptive TRansform Acoustic Coding
3.2.3
ATRAC2
Adaptive TRansform Acoustic Coding 2
3.2.4
ATRAC3
Adaptive TRansform Acoustic Coding 3
3.2.5
ATRAC2/3
ATRAC2 and/or ATRAC3
3.2.6
ATSC
Advanced Television Systems Committee
3.2.7
DTS
Digital Theatre Systems
3.2.8
MPEG
Moving Pictures Expert Group, a joint committee of ISO and IEC
3.2.9
ITU-R
International Telecommunication Union, Radio Communication Bureau
3.2.10
SMPTE
Society of Motion Picture and Television Engineers
3.3 Presentation convention
F872h
Value ‘F872’ in hexadecimal format

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