ISO/IEC 14496-12:2015/Amd 1:2017

INTERNATIONAL ISO/IEC
STANDARD 14496-12
Fifth edition
2015-12-15
AMENDMENT 1
2017-03
Information technology — Coding of
audio-visual objects —
Part 12:
ISO base media file format
AMENDMENT 1: DRC Extensions
Technologies de l’information — Codage des objets audiovisuels —
Partie 12: Format ISO de base pour les fichiers médias
AMENDEMENT 1: Extensions DRC
Reference number
ISO/IEC 14496-12:2015/Amd.1:2017(E)
©
ISO/IEC 2017
ISO/IEC 14496-12:2015/Amd.1:2017(E)

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ii © ISO/IEC 2017 – All rights reserved

ISO/IEC 14496-12:2015/Amd.1:2017(E)

Foreword
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work. In the field of information technology, ISO and IEC have established a joint technical committee,
ISO/IEC JTC 1.
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Amendment 1 to ISO/IEC 14496‑12:2015 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 2017 – All rights reserved iii

ISO/IEC 14496-12:2015/Amd.1:2017(E)
Information technology — Coding of audio-visual
objects —
Part 12:
ISO base media file format
AMENDMENT 1: DRC Extensions
Page 1, Normative references
Add the following new reference:
ISO/IEC 23003-4:2015/Amd.1, Information technology — MPEG audio technologies — Part 4: Dynamic
range control, AMENDMENT 1: Parametric DRC, gain mapping and equalization tools.
Replace the normative reference:
ITU-R, Recommendation ITU-R BS.1770-3. Algorithm to measure audio programme loudness and true-
peak audio level, August 2012.
with:
ITU-R, Recommendation ITU-R BS.1770-4. Algorithms to measure audio programme loudness and true-
peak audio level, October 2015.
Page 2, Terms and definitions
Add the following new definition after 3.1.8 and adjust subsequent term numbers:
3.1.9
mod
modulo operator: (x mod y) = x-y floor (x/y)
Page 160, 12.2.3.1
Add the following paragraph at the end of the subclause:
Encoders should encode the DRC-related boxes in the AudioSampleEntry in the order given in
12.2.3.2. Decoders may ignore and discard the DRC‑related boxes if they are not in that order. DRC‑
related boxes include ChannelLayout, DownMixInstructions, DRCCoefficientsBasic,
DRCInstructionsBasic, DRCCoefficientsUniDrc, DRCInstructionsUniDrc, and
UniDrcConfigExtension. The DownMixInstructions and DRCInstructionsUniDrc box
cannot occur more than once if the box has version==1, but it can occur multiple times if version==0.
ISO/IEC 14496-12:2015/Amd.1:2017(E)

Page 161, 12.2.3.2
Replace the definition of AudioSampleEntry and AudioSampleEntryV1 with:
class AudioSampleEntry(codingname) extends SampleEntry (codingname){
const unsigned int(32)[2] reserved = 0;
template unsigned int(16) channelcount = 2;
template unsigned int(16) samplesize = 16;
unsigned int(16) pre_defined = 0;
const unsigned int(16) reserved = 0 ;
template unsigned int(32) samplerate = { default samplerate of media}<<16;
// optional boxes follow
Box ();    // further boxes as needed
ChannelLayout();
DownMixInstructions() [];
DRCCoefficientsBasic() [];
DRCInstructionsBasic() [];
DRCCoefficientsUniDRC() [];
DRCInstructionsUniDRC() [];
// we permit only one DRC Extension box:
UniDrcConfigExtension();
Box ();    // further boxes as needed
}
aligned(8) class SamplingRateBox extends FullBox('srat') {
unsigned int(32) sampling_rate;
}
class AudioSampleEntryV1(codingname) extends SampleEntry (codingname){
unsigned int(16) entry_version;  // must be 1,
// and must be in an stsd with version ==1
const unsigned int(16)[3] reserved = 0;
template unsigned int(16) channelcount;  // must be correct
template unsigned int(16) samplesize = 16;
unsigned int(16) pre_defined = 0;
const unsigned int(16) reserved = 0 ;
template unsigned int(32) samplerate = 1<<16;
// optional boxes follow
SamplingRateBox();
Box ();    // further boxes as needed
ChannelLayout();
DownMixInstructions() [];
DRCCoefficientsBasic() [];
DRCInstructionsBasic() [];
DRCCoefficientsUniDRC() [];
DRCInstructionsUniDRC() [];
// we permit only one DRC Extension box:
UniDrcConfigExtension();
Box ();    // further boxes as nee
...