ISO/IEC 23003-4:2015
(Main)Information technology — MPEG audio technologies — Part 4: Dynamic Range Control
Information technology — MPEG audio technologies — Part 4: Dynamic Range Control
ISO/IEC 23003-4:2015 specifies technology for loudness and dynamic range control. ISO/IEC 23003-4:2015 is applicable to most MPEG audio technologies. It offers flexible solutions to efficiently support the widespread demand for technologies such as loudness normalization and dynamic range compression for various playback scenarios.
Technologies de l'information — Technologies audio MPEG — Partie 4: Contrôle de gamme dynamique
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Standards Content (Sample)
INTERNATIONAL ISO/IEC
STANDARD 23003-4
First edition
2015-11-15
Information technology — MPEG
audio technologies —
Part 4:
Dynamic Range Control
Technologies de l’information — Technologies audio MPEG —
Partie 4: Contrôle de gamme dynamique
Reference number
©
ISO/IEC 2015
© ISO/IEC 2015, Published in Switzerland
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ii © ISO/IEC 2015 – All rights reserved
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and mnemonics . 1
3.1 Terms . 1
3.2 Mnemonics . 2
4 Symbols (and abbreviated terms) . 2
5 Technical overview . 3
6 DRC decoder . 4
6.1 DRC decoder configuration . 4
6.1.1 Overview . 4
6.1.2 Description of logical blocks . 5
6.1.3 Derivation of peak and loudness values . 8
6.2 Dynamic DRC gain payload .11
6.3 DRC set selection .12
6.3.1 Overview .12
6.3.2 Pre-selection based on Signal Properties and Decoder Configuration .13
6.3.3 Selection based on requests .16
6.3.4 Final selection .18
6.3.5 Applying multiple DRC sets .18
6.3.6 Album mode .19
6.3.7 Ducking .19
6.3.8 Precedence .19
6.4 Time domain DRC application .19
6.4.1 Overview .19
6.4.2 Framing .20
6.4.3 Time resolution .20
6.4.4 Time alignment .20
6.4.5 Decoding .20
6.4.6 Gain modifications and interpolation .24
6.4.7 Spline interpolation . .28
6.4.8 Look-ahead in decoder .28
6.4.9 Node reservoir .29
6.4.10 Applying the compression .30
6.4.11 Multi-band DRC filter bank .33
6.5 Sub-band domain DRC .37
6.6 Loudness normalization .40
6.6.1 Overview .40
6.6.2 Loudness normalization based on target loudness .40
6.7 DRC in streaming scenarios .43
6.7.1 DRC configuration .43
6.7.2 Error handling .43
6.8 DRC configuration changes during active processing .43
7 Syntax .45
7.1 Syntax of DRC payload .45
7.2 Syntax of DRC gain payload .46
7.3 Syntax of static DRC payload .47
7.4 Syntax of DRC gain sequence .59
Annex A (normative) Tables .60
Annex B (normative) External Interface to DRC tool .74
© ISO/IEC 2015 – All rights reserved iii
Annex C (informative) Audio codec specific information .85
Annex D (informative) DRC gain generation and encoding .90
Annex E (informative) DRC set selection and adjustment at decoder .95
Annex F (informative) Loudness normalization .100
Annex G (informative) Peak limiter .101
Bibliography .106
iv © ISO/IEC 2015 – All rights reserved
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 document 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 and IEC 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 WTO principles in the Technical
Barriers to Trade (TBT), see the following URL: Foreword — Supplementary information.
The committee responsible for this document is ISO/IEC JTC 1, Information Technology, Subcommittee
SC 29, Coding of audio, picture, multimedia, and hypermedia.
ISO/IEC 23003 consists of the following parts, under the general title Information technology — MPEG
audio technologies:
— Part 1: MPEG Surround
— Part 2: Spatial Audio Object Coding
— Part 3: Unified speech and audio coding
— Part 4: Dynamic Range Control
© ISO/IEC 2015 – All rights reserved v
Introduction
Consumer audio systems and devices are used in a large variety of configurations and acoustical
environments. For many of these scenarios, the audio reproduction quality can be improved by
appropriate control of content dynamics and loudness.
This part of ISO/IEC 23003 provides a universal dynamic range control tool that supports loudness
normalization. The DRC tool offers a bitrate efficient representation of dynamically compressed
versions of an audio signal. This is achieved by adding a low-bitrate DRC
...
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