ISO/IEC 23003-3:2012/Amd 3:2016
(Amendment)Information technology — MPEG audio technologies — Part 3: Unified speech and audio coding — Amendment 3: Support of MPEG-D DRC, audio pre-roll and immediate play-out frame
Information technology — MPEG audio technologies — Part 3: Unified speech and audio coding — Amendment 3: Support of MPEG-D DRC, audio pre-roll and immediate play-out frame
Technologies de l'information — Technologies audio MPEG — Partie 3: Discours unifié et codage audio — Amendement 3: Support de DRC MPEG-D, message préliminaire audio et cadre de lecture immédiat
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INTERNATIONAL ISO/IEC
STANDARD 23003-3
First edition
2012-04-01
AMENDMENT 3
2016-08-01
Information technology — MPEG
audio technologies —
Part 3:
Unified speech and audio coding
AMENDMENT 3: Support of MPEG-D
DRC, audio pre-roll and immediate play-
out frame
Technologies de l’information — Technologies audio MPEG —
Partie 3: Discours unifié et codage audio
AMENDEMENT 3: Support de DRC MPEG-D, message préliminaire
audio et cadre de lecture immédiat
Reference number
ISO/IEC 23003-3:2012/Amd.3:2016(E)
©
ISO/IEC 2016
---------------------- Page: 1 ----------------------
ISO/IEC 23003-3:2012/Amd.3:2016(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
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ISO copyright office
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Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
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ii © ISO/IEC 2016 – All rights reserved
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ISO/IEC 23003-3:2012/Amd.3:2016(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical
activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work. In the field of information technology, ISO and IEC have established a joint technical committee,
ISO/IEC JTC 1.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.
Amendment 3 to ISO/IEC 23003-3:2012 was prepared by Joint Technical Committee ISO/IEC JTC 1,
Information technology, Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia
information.
© ISO/IEC 2016 – All rights reserved iii
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ISO/IEC 23003-3:2012/Amd.3:2016(E)
Information technology — MPEG audio technologies —
Part 3:
Unified speech and audio coding
AMENDMENT 3: Support of MPEG-D DRC, audio pre-roll and
immediate play-out frame
Page 1, Normative references
Add the following reference:
ISO/IEC 23003-4, Information technology — MPEG audio technologies — Part 4: Dynamic Range Control
Page 4, 4.4
Add new subclause at the end of 4.4:
4.4.1 Decoder behaviour
4.4.1.1 General decoding process
The decoder shall operate in such a way that the decoding of one access unit shall always and immediately
produce one full composition unit of audio signal data (one audio frame with outputFrameLength
number of samples).
The decoder shall not discard any audio samples. In particular the decoder shall make no assumptions
about encoder delay and shall also not attempt to compensate assumed encoder processing delay by
removing audio samples from the composition unit buffer.
Discarding of audio samples due to the presence of an EditListBox as described in Annex F is not part of
the normative USAC decoder but shall be applied by the MPEG-4 Systems infrastructure.
4.4.1.2 Initialization and re-initialization of the USAC decoder
Upon (re-) initialization all decoder internal signal buffers shall be set to zero.
Due to the initialized state of the decoder internal buffers, the decoder output may contain “start-up
samples” when decoding the first access units of a given compressed data stream.
These start-up samples are samples that do not have a direct relation to the audio input data and are
typically zero-valued and may be discarded by the Systems infrastructure.
The number of start-up samples to be discarded may for example be transmitted by means of the
media_time field in the EditListbox in an ISO Base Media file format environment. Note that this must
be done by the encoder.
If a given USAC decoder implementation produces more than the minimum number of start-up
samples (i.e. it creates additional decoder delay), the number of additional samples must be reported
by the decoder to the Systems infrastructure. Systems infrastructure shall then correctly apply delay
compensation or time-alignment.
© ISO 2016 – All rights reserved 1
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ISO/IEC 23003-3:2012/Amd.3:2016(E)
4.4.1.3 Decoding process of access unit with audio pre-roll
The decoding process of access units with embedded audio pre-roll frames is identical to the above
description.
The presence of audio pre-roll in the first access unit prepares the decoder internal signal buffers. This
allows an encoder to produce a compressed data stream, that will cause the decoder output buffer to
contain less or no start-up samples.
The decoding description when changing from one configuration to another while employing audio
pre-roll is described in 7.18.3.3.
If a given decoder implementation produces additional start-up samples (additional decoder delay),
then the flushing of the old configuration (FlushDecoder()) shall be increased by the same amount of
samples. The signal crossfade must be delayed accordingly. The decoder must ensure that the number
of additional start-up samples (additional decoder delay) does not change when switching to another
stream in the adaptation set.
Page 11, 4.5.3
Add the following paragraph at the end of 4.5.3:
Furthermore the following requirements apply:
— The number of pre-roll frames, numPreRollFrames, in an AudioPreRoll() extension payload shall
not exceed 3.
— Decoders conforming to the Baseline USAC profile shall support the full decoding and correct
handling of the AudioPreRoll() extension.
NOTE The number of pre-roll frames required for seamless operation of the audio codec may be lower than
the above mentioned number. See B.26 for encoder implementation guide lines.
Page 12, Clause 4
Add new subclause at the end of Clause 4:
4.6 Combination of USAC with MPEG-D DRC
The output of the USAC decoder can be further processed by MPEG-D DRC (ISO/IEC 23003-4). If the SBR
tool in USAC is active, a USAC decoder can typically be efficiently combined with a subsequent MPEG-D
DRC decoder by connecting them in the QMF domain in the same way as it is described in ISO/IEC 23003-
4. If a connection in the QMF domain is not possible they shall be connected in the time domain.
The MPEG-D DRC payload shall be embedded into a USAC bitstream by means of the usacExtElement
mechanism, with usacExtElementType of type ID_EXT_ELE_UNI_DRC. The loudness metadata shall be
embedded by means of the usacConfigExt mechanism with usacConfigExtType of type ID_CONFIG_
EXT_LOUDNESS_INFO. The time-alignment between the USAC data and the MPEG-D DRC data assumes
the most efficient connection between the USAC decoder and the MPEG-D DRC decoder. If the SBR tool
in USAC is active, the most efficient connection is in the QMF domain. Otherwise, the most efficient
connection is in the time domain. The DRC tool is operated in regular delay mode and the DRC frame
size has the same duration as the USAC frame size. The same holds for the DRC sampling rate, which is
synchronized to the USAC sampling rate.
2 © ISO 2016 – All rights reserved
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ISO/IEC 23003-3:2012/Amd.3:2016(E)
The time resolution of the DRC tool is specified by deltaTmin in units of the audio sample interval. It is
calculated as specified in ISO/IEC 23003-4. Specific values are provided here as examples based on the
following formula:
M
deltaTmin= 2
The applicable exponent M is found by looking up the audio sample rate range that fulfils:
ff≤< f
ss,min s,max
Table — AMD3.1 — Lookup table for the exponent M
fs,min [Hz] fs,max [Hz] M
8000 16000 3
16000 32000 4
32000 64000 5
64000 128000 6
Given the codec frame size N (==outputFrameLength), the DRC frame size in units of DRC samples
Codec
at a rate of deltaTmin is:
−M
NN= 2
DRCCodec
For USAC, MPEG-D DRC offers mandatory decoding capability of up to four DRC subbands using the
time-domain DRC filter bank. More DRC subbands can be supported by operating in the QMF-domain.
DRC sets that contain more than four DRC subbands must contain gain sequences that are all aligned
with the QMF-domain used for SBR. If the SBR tool in USAC is active, MPEG-D DRC shall always operate
in the QMF-domain. The gain sequences are all aligned with the QMF domain in that case.
If no additional filter bank is required for the application of multiband DRC gains, MPEG-D DRC doesn’t
introduce any additional decoding delay.
The drcLocation parameter shall be encoded according to Table AMD3.2.
Table — AMD3.2 — Encoding of drcLocation parameter
drcLocation n Payload
1 uniDrcConfig() / uniDrcGain() (see ISO/IEC 23003-4)
2 reserved
3 reserved
4 reserved
© ISO 2016 – All rights reserved 3
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ISO/IEC 23003-3:2012/Amd.3:2016(E)
Page 16, Table 14
Replace Table 14 with the following table:
Table 14 — Syntax of UsacExtElementConfig()
Syntax No. of bits Mnemonic
UsacExtElementConfig()
{
usacExtElementType = escapedValue(4,8,16);
usacExtElementConfigLength = escapedValue(4,8,16);
usacExtElementDefaultLengthPresent; 1 uimsbf
if (usacExtElementDefaultLengthPresent) {
usacExtElementDefaultLength = escapedValue(8,16,0) + 1;
} else {
usacExtElementDefaultLength = 0;
}
usacExtElementPayloadFrag; 1 uimsbf
switch (usacExtElementType) {
case ID_EXT_ELE_FILL:
break;
case ID_EXT_ELE_MPEGS:
SpatialSpecificConfig();
break;
case ID_EXT_ELE_SAOC:
SaocSpecificConfig();
break;
case ID_EXT_ELE_AUDIOPREROLL:
/* No configuration element */
break;
case ID_EXT_ELE_UNI_DRC:
uniDrcConfig();
break;
default: NOTE
while (usacExtElementConfigLength--) {
tmp; 8 uimsbf
}
break;
}
}
NOTE: The default entry for the usacExtElementType is used for unknown extElementTypes so that legacy
decoders can cope with future extensions.
4 © ISO 2016 – All rights reserved
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ISO/IEC 23003-3:2012/Amd.3:2016(E)
Page 16, Table 15
Replace Table 15 with the following table:
Table 15 — Syntax of UsacConfigExtension()
Syntax No. of bits Mnemonic
UsacConfigExtension()
{
numConfigExtensions = escapedValue(2,4,8) + 1;
for (confExtIdx=0; confExtIdx
usacConfigExtType[confExtIdx] = escapedValue(4,8,16);
usacConfigExtLength[confExtIdx] = escapedValue(4,8,16);
switch (usacConfigExtType[confExtIdx]) {
case ID_CONFIG_EXT_FILL:
while (usacConfigExtLength[confExtIdx]--) {
fill_byte[i]; /* should be ‘10100101’ */ 8 uimsbf
}
break;
case ID_CONFIG_EXT_LOUDNESS_INFO:
loudnessInfoSet()
break;
default:
while (usacConfigExtLength[confExtIdx]--) {
tmp; 8 uimsbf
}
break;
}
}
}
© ISO 2016 – All rights reserved 5
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ISO/IEC 23003-3:2012/Amd.3:2016(E)
Page 50, Clause 5
Add new subclause at the end of Clause 5:
5.3.5 Payload of extension elements
Table — AMD3.3 — Syntax of AudioPreRoll()
Syntax No. of bits Mnemonic
AudioPreRoll()
{
configLen = escapedValue(4,4,8); 4.16
Config() 8*configLen
applyCrossfade; 1 bool
reserved; 1 bool
numPreRollFrames = escapedValue(2,4,0); 2.6
for (frameIdx=0; frameIdx < numPreRollFrames; ++frameIdx) {
auLen = escapedValued(16,16,0) 16.32 uimsbf
AccessUnit() 8*auLen
}
}
Page 58, Table 73
Replace Table 73 with the following table:
Table 73 — Value of usacExtElementType
usacExtElementType Value
ID_EXT_ELE_FILL 0
ID_EXT_ELE_MPEGS 1
ID_EXT_ELE_SAOC 2
ID_EXT_ELE_AUDIOPREROLL 3
ID_EXT_ELE_UNI_DRC 4
/* reserved for ISO use */ 5-127
/* reserved for use outside of ISO scope */ 128 and higher
NOTE Application-specific usacExtElementType values are mandated to be in the space
reserved for use outside of ISO scope. These are skipped by a decoder as a minimum of
structure is required by the decoder to skip these extensions.
6 © ISO 2016 – All rights reserved
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ISO/IEC 23003-3:2012/Amd.3:2016(E)
Page 58, Table 74
Replace Table 74 with the following table:
Table 74 — Value of usacConfigExtType
usacConfigExtType Value
ID_CONFIG_EXT_FILL 0
/* reserved for ISO use */ 1
ID_CONFIG_EXT_LOUDNESS_INFO 2
/* reserved for ISO use */ 3-127
/* reserved for use outside of ISO scope */ 128 and higher
Page 64, Table 81
Replace Table 81 with the following table:
Table 81 — Interpretation of data
...
DRAFT AMENDMENT
ISO/IEC 23003-3:2012/DAM 3
ISO/IEC JTC 1/SC 29 Secretariat: JISC
Voting begins on: Voting terminates on:
2015-09-28 2015-12-28
Information technology — MPEG audio technologies —
Part 3:
Unified speech and audio coding
AMENDMENT 3: Support of MPEG-D DRC
Technologies de l’information — Technologies audio MPEG —
Partie 3: Discours unifié et codage audio
AMENDEMENT 3: .
ICS: 35.040
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/IEC 23003-3:2012/DAM 3:2015(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO/IEC 2015
---------------------- Page: 1 ----------------------
ISO/IEC 23003-3:2012/DAM 3:2015(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO/IEC 2015 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/IEC 23003-3:2012/DAM 3
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
Amendment 3 to ISO/IEC 23003-3:2012 was prepared by Joint Technical Committee ISO/IEC JTC 1,
Information technology, Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia
information.
iv © ISO/IEC 2015 – All rights reserved
---------------------- Page: 3 ----------------------
DRAFT AMENDMENT ISO/IEC 23003-3:2012/DAM 3
Information technology — MPEG audio technologies — Part 3:
Unified speech and audio coding, AMENDMENT 3: Support of
MPEG-D DRC
1 Changes to the text of ISO/IEC 23003-3:2012
In Clause 2 Normative References add:
ISO/IEC 23003-4, “Information technology — MPEG audio technologies — Part 4: Dynamic Range Control”
In Clause 4 add new sub-clause:
4.xx Combination of USAC with MPEG-D DRC
The output of the USAC decoder can be further processed by MPEG-D DRC (ISO/IEC 23003-4). If the SBR
tool in USAC is active, a USAC decoder can typically be efficiently combined with a subsequent MPEG-D
DRC decoder by connecting them in the QMF domain in the same way as it is described in ISO/IEC 23003-4.
If a connection in the QMF domain is not possible they shall be connected in the time domain.
The MPEG-D DRC payload shall be embedded into a USAC bitstream by means of the usacExtElement
mechanism, with usacExtElementType of type ID_EXT_ELE_UNI_DRC. The loudness metadata shall be
embedded by means of the usacConfigExt mechanism with usacConfigExtType of type
ID_CONFIG_EXT_LOUDNESS_INFO. The time-alignment between the USAC data and the MPEG-D DRC
data assumes the most efficient connection between the USAC decoder and the MPEG-D DRC decoder. If
the SBR tool in USAC is active, the most efficient connection is in the QMF domain. Otherwise, the most
efficient connection is in the time domain. The DRC tool is operated in regular delay mode and the DRC frame
size has the same duration as the USAC frame size. The same holds for the DRC sampling rate, which is
synchronized to the USAC sampling rate.
The time resolution of the DRC tool is specified by deltaTmin in units of the audio sample interval. It is
calculated as specified in ISO/IEC 23003-4. Specific values are provided here as examples based on the
following formula:
M
deltaTmin = 2
.
The applicable exponent M is found by looking up the audio sample rate range that fulfills:
f ≤ f < f .
s,min s s,max
Table AMD3.1 --- Lookup table for the exponent M
fs,min [Hz] fs,max [Hz] M
8000 16000 3
16000 32000 4
32000 64000 5
© ISO/IEC 2015 – All rights reserved 1
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ISO/IEC 23003-3:2012/DAM 3
64000 128000 6
Given the codec frame size N (==outputFrameLength), the DRC frame size in units of DRC samples at a
Codec
rate of deltaTmin is:
−M
N =N 2 .
DRC Codec
For USAC, MPEG-D DRC offers mandatory decoding capability of up to four DRC subbands using the time-
domain DRC filter bank. More DRC subbands can be supported by operating in the QMF-domain. DRC sets
that contain more than four DRC subbands must contain gain sequences that are all aligned with the QMF-
domain used for SBR. If the SBR tool in USAC is active, MPEG-D DRC shall always operate in the QMF-
domain. The gain sequences are all aligned with the QMF domain in that case.
If no additional filter bank is required for the application of multiband DRC gains, MPEG-D DRC doesn’t
introduce any additional decoding delay.
The drcLocation parameter shall be encoded according to Table AMD3.2.
Table AMD3.2 - Encoding of drcLocation parameter
drcLocation n Payload
1 uniDrcConfig() / uniDrcGain() (see ISO/IEC 23003-4)
2 reserved
3 reserved
4 reserved
In Clause 5, replace Table 14 with:
Table 14 — Syntax of UsacExtElementConfig()
Syntax No. of bits Mnemonic
UsacExtElementConfig()
{
usacExtElementType = escapedValue(4,8,16);
usacExtElementConfigLength = escapedValue(4,8,16);
usacExtElementDefaultLengthPresent; 1 uimsbf
if (usacExtElementDefaultLengthPresent) {
usacExtElementDefaultLength = escapedValue(8,16,0) + 1;
} else {
usacExtElementDefaultLength = 0;
}
usacExtElementPayloadFrag; 1 uimsbf
switch (usacExtElementType) {
case ID_EXT_ELE_FILL:
break;
case ID_EXT_ELE_MPEGS:
SpatialSpecificConfig();
break;
case ID_EXT_ELE_SAOC:
2 © ISO/IEC 2015 – All rights reserved
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ISO/IEC 23003-3:2012/DAM 3
SaocSpecificConfig();
break;
case ID_EXT_ELE_AUDIOPREROLL:
/* No configuration element */
break;
case ID_EXT_ELE_UNI_DRC:
uniDrcConfig();
break;
default: NOTE
while (usacExtElementConfigLength--) {
tmp; 8 uimsbf
}
break;
}
}
NOTE: The default entry for the usacExtElementType is used for unknown extElementTypes so that
legacy decoders can cope with future extensions.
In Clause 5 replace Table 15 with:
Table 15 — Syntax of UsacConfigExtension()
Syntax No. of bits Mnemonic
UsacConfigExtension()
{
numConfigExtensions = escapedValue(2,4,8) + 1;
for (confExtIdx=0; confExtIdx
usacConfigExtType[confExtIdx] = escapedValue(4,8,16);
usacConfigExtLength[confExtIdx] = escapedValue(4,8,16);
switch (usacConfigExtType[confExtIdx]) {
case ID_CONFIG_EXT_FILL:
while (usacConfigExtLength[confExtIdx]--) {
fill_byte[i]; /* should be '10100101' */ 8 uimsbf
}
break;
case ID_CONFIG_EX
...
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