ISO/IEC 14496-3:2019/FDAmd 1

• Status: Not Published
• ICS: 35.040.40 - Coding of audio, video, multimedia and hypermedia information
• Technical Committee: ISO/IEC JTC 1/SC 29 - Coding of audio, picture, multimedia and hypermedia information
• Drafting Committee: ISO/IEC JTC 1/SC 29/WG 6 - MPEG Audio coding
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 03-Aug-2026
• Completion Date: 03-Aug-2026

• Amends: ISO/IEC 14496-3:2019 - Information technology — Coding of audio-visual objects — Part 3: Audio
• Effective Date: 10-May-2025

Overview

ISO/IEC 14496-3:2019/FDAM 1:2026 is an ISO standard amendment that advances audio processing in multimedia systems. This amendment to the widely adopted MPEG-4 Audio standard introduces critical features for media authenticity and an immersive interchange format (IIF) for audio coding. By addressing audio authenticity and suitability for immersive audio experiences, it enhances reliable, flexible, and secure media interchange across diverse applications.

As digital audio grows in complexity and usage scenarios, ensuring the integrity and interchangeability of audio elements is increasingly vital. This standard provides updated definitions, object types, profiles, and levels reflecting the needs of cutting-edge media workflows and immersive environments.

Key Topics

• Media Authenticity in Audio
  The amendment incorporates mechanisms to support media authenticity verification. This is crucial for validating the origin and integrity of audio data, helping to prevent tampering or unauthorized modifications in media distribution chains.

• Immersive Interchange Format (IIF)
  A new AAC IIF object type (audio object type 47) and Immersive Interchange Profile are introduced. IIF supports complex immersive audio workflows, such as multi-channel and 3D audio, catering to applications like virtual reality (VR), augmented reality (AR), and advanced broadcasting.

• Updated Audio Profiles and Levels
  The document details updates to MPEG-4 audio profiles and levels, particularly for immersive audio use, expanding on channel counts, sampling rates, metadata handling, and buffer management for high-fidelity, multi-dimensional audio content.

• Enhanced Syntax and Metadata Handling
  Additions to bitstream syntax support the new features, including payload structures optimized for immersive audio, robust metadata payload formats, and explicit mechanisms for configuration updates and lossless modes.

Applications

• Digital Media Production & Distribution
  The IIF facilitates seamless exchange of immersive audio content between devices, platforms, and editing tools-crucial for music production, film post-production, and interactive media authoring.

• Content Authenticity Verification
  Embedded media authenticity checks ensure that recipients or playback systems can verify the provenance and integrity of audio assets. This is especially valuable for media forensics, archival systems, and compliance-driven sectors.

• Broadcasting and Streaming Services
  Enhanced profiles and object types optimize broadcast workflows, reduce compatibility issues, and enable deployment of multichannel sound for live events and OTT platforms.

• Virtual & Augmented Reality
  IIF object types and profiles allow the efficient interchange of spatial audio, supporting experiences that require accurate 3D positioning and high quality across diverse playback systems.

• Archiving and Preservation
  Clear metadata structures and authenticity tools assist in long-term preservation, ensuring that archived audio can be trusted and easily re-integrated into future media technologies.

Related Standards

• ISO/IEC 14496-3:2019 - The parent standard for MPEG-4 Audio coding.
• ISO/IEC 23091-3 - Coding-independent code-points for audio, supporting interoperability.
• IETF RFC 3986 - Uniform Resource Identifier (URI): Generic Syntax, for referencing media objects.
• IETF RFC 9562 - Universally Unique Identifiers (UUIDs), facilitating unique asset identification.
• ISO/IEC 14496-35 - Reference software for MPEG-4 audio techniques.
• ISO/IEC 23003-3 - Audio object technology, relevant for UsacAotSpecificConfig.

By aligning with these standards, ISO/IEC 14496-3:2019/FDAM 1:2026 ensures interoperability and supports evolving requirements in the global audio and multimedia landscape.

FINAL DRAFT
Amendment
ISO/IEC
14496-3:2019/
FDAM 1
ISO/IEC JTC 1/SC 29
Information technology — Coding of
Secretariat: JISC
audio-visual objects —
Voting begins on:
2026-08-03
Part 3:
Audio
Voting terminates on:
2026-09-28
AMENDMENT 1: Media authenticity
and immersive interchange format
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 SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
ISO/IEC 14496­3:2019/FDAM 1:2026(en) © ISO/IEC 2026

FINAL DRAFT
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
Amendment
ISO/IEC
14496-3:2019/
FDAM 1
ISO/IEC JTC 1/SC 29
Information technology — Coding of
Secretariat: JISC
audio-visual objects —
Voting begins on:
Part 3:
Audio
Voting terminates on:
AMENDMENT 1: Media authenticity
and immersive interchange format
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 SUPPOR TING DOCUMENTATION.
© ISO/IEC 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/IEC 14496­3:2019/FDAM 1:2026(en) © ISO/IEC 2026

© ISO/IEC 2026 – All rights reserved
ii
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
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.
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 or www.iec.ch/members_experts/refdocs).
ISO and IEC draw attention to the possibility that the implementation of this document may involve the
use of (a) patent(s). ISO and IEC take no position concerning the evidence, validity or applicability of any
claimed patent rights in respect thereof. As of the date of publication of this document, ISO and IEC had not
received notice of (a) patent(s) which may be required to implement this document. However, implementers
are cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents and https://patents.iec.ch. ISO and IEC shall not be held
responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, 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 www.iso.org/iso/foreword.html.
In the IEC, see www.iec.ch/understanding-standards.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information.
A list of all parts in the ISO/IEC 14496 series can be found on the ISO and IEC websites.
Any feedback or questions on this document should be directed to the user’s national standards
body. A complete listing of these bodies can be found at www.iso.org/members.html and
www.iec.ch/national-committees.

© ISO/IEC 2026 – All rights reserved
iii
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
Information technology — Coding of audio-visual objects —
Part 3:
Audio
AMENDMENT 1: Media authenticity and immersive interchange
format
Replace T.130 and T.131 with the following:
T.130
NCC
number of considered channels
number of channels represented by the elements SCE, independently switched CCE and CPE, i.e. once
the number of SCEs plus once the number of independently switched CCEs plus twice the number of CPEs.
Note 1 to entry This number is used to derive the required decoder input buffer size (see subpart 4, subclause 4.5.3.1).

Add the following at the end of Section 1.2:
IETF RFC 3986, Uniform Resource Identifier (URI): Generic Syntax
IETF RFC 9562, Universally Unique IDentifiers (UUIDs)
ISO/IEC 23091-3, Information technology — Coding-independent code-points — Part 3: Audio

Add the following line in Section 1.4.7 below the line defining “uimsbf” and before the line defining “vlclbf”:
tcimsbf Two’s complement integer, most significant (sign) bit first.

Add the following lines at the end of Table 1.1:
a
47 AAC IIF
48-63 Reserved for 14496-3
64-95 Reserved for 23003-3
a
Details on syntax elements and tools are defined in 1.5.1.2.43.

At the end of 1.5.1.2, add the following:
1.5.1.2.43  AAC - Immersive Interchange Format (IIF) object type
The AAC IIF object type contains the codec defined in 4.6.21.

© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
It is based on the ER AAC LD object type and contains the tools and modules of the ER AAC LD object type
according to Table 1.1 except for the AAC ER tools, the ER payload syntax module, the EP tool, the LTP tool
and pulse data.
It contains all characteristics, tools, modules, processing steps and syntax elements defined in 4.6.21,
4.4.2.10, 4.5.2.18 and Annex 4.C.

At the end of 1.5.2.1, add the following:
16.  The Immersive Interchange Profile contains the audio object type 47 (AAC IIF).

Replace Table 1.3 with the following:
Table 1.3 — Audio Profiles definition
Audio Object
Type
0 Null
1 AAC main  X X
2 AAC LC X X X X X X X X
3 AAC SSR  X X
4 AAC LTP X X X X
5 SBR     X X
6 AAC Scalable X X X X
7 TwinVQ X X X
8 CELP X X X X X X
9 HVXC X X X X X
10 (reserved)
11 (reserved)
12 TTSI X X X X X X
13 Main synthetic X X
14 Wavetable syn- X* X*
thesis
15 General MIDI X* X*
16 Algorithmic Syn- X* X*
thesis and Audio
FX
17 ER AAC LC  X X X
© ISO/IEC 2026 – All rights reserved
Object Type ID
Speech Audio Profile
Synthetic Audio Profile
Scalable Audio Profile
Main Audio Profile
High Quality Audio Profile
Low Delay Audio Profile
Natural Audio Profile
Mobile Audio Internetworking Profile
AAC Profile
High Efficiency AAC Profile
High Efficiency AAC v2 Profile
Low Delay AAC Profile
High Definition AAC Profile
ALS Simple Profile
Low Delay AAC v2 Profile
Immersive Interchange Profile
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
TTaabblle 1.e 1.3 3 ((ccoonnttiinnueuedd))
Audio Object
Type
18 (reserved)
19 ER AAC LTP  X X
20 ER AAC Scalable  X X X
21 ER TwinVQ   X X
22 ER BSAC   X X
23 ER AAC LD   X X X  X X
24 ER CELP  X X X
25 ER HVXC   X X
26 ER HILN   X
27 ER Parametric   X
28 SSC
29 PS     X
30 MPEG Surround
31 (escape)
32 Layer-1
33 Layer-2
34 Layer-3
35 DST
36 ALS       X
37 SLS      X
38 SLS non-core
39 ER AAC ELD       X
40 SMR Simple
41 SMR Main
42 USAC
43 SAOC
44 LD MPEG Sur-       X
round
45 SAOC-DE
46 Audio Sync
47 AAC IIF        X
*) Subset of Main Synthetic
© ISO/IEC 2026 – All rights reserved
Object Type ID
Speech Audio Profile
Synthetic Audio Profile
Scalable Audio Profile
Main Audio Profile
High Quality Audio Profile
Low Delay Audio Profile
Natural Audio Profile
Mobile Audio Internetworking Profile
AAC Profile
High Efficiency AAC Profile
High Efficiency AAC v2 Profile
Low Delay AAC Profile
High Definition AAC Profile
ALS Simple Profile
Low Delay AAC v2 Profile
Immersive Interchange Profile
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
At the end of 1.5.2.3, add the following:
— Levels for the Immersive Interchange Profile
The levels for the Immersive Interchange Profile are specified in Table 1.17.
Table 1.17 — Levels for the Immersive Interchange Profile
Level Max. Max. Max. out_ Max. Max. Max. Max. IIF Max. buffer Max.
NCC audio_bus_ sampling_ audio_bus_ number of frame_ Block for meta- metadata
a
width rate_multi- width predefined length_idx Streams data (accu- instances
b
plier audio pres- mulated)
multi- (number of
entations [KiB]
plied by different
(num_
out_sam- meta-
audio_
pling_rate_ data_in-
b
presenta-
multiplier stance_tag
tions)
values)
1 6 8 1 2 1 15 4 8 1
2 24 32 2 16 32 31 32 64 24
3 48 64 2 32 64 31 32 128 64
4 48 128 2 48 128 31 32 256 128
5 48 256 4 64 256 31 32 512 256
6 768 256 4 256 256 31 32 8,192 256
7 3072 256 4 1024 256 31 32 8,192 256
a
These restrictions apply if lossless coding is disabled, i.e. if none of the elements in the vector b_block_priority0_is_lossless is
equal to 1 in an iif_specific_config().
b
These restrictions apply if lossless coding is enabled, i.e. if any of the elements in the vector b_block_priority0_is_lossless is
equal to 1 in an iif_specific_config().

All levels shall support Media Authenticity as defined in 4.5.2.17, including the Media Authenticity Interface
according to 4.5.2.17.3.
Update numbering of Table 1.17 to 1.18 and add the following rows after the row starting with “0x5E”:
0x5F ALS Simple Profile L5
0x60 ALS Simple Profile L6
0x61 ALS Simple Profile L7
0x62 AAC IIF Profile L1
0x63 AAC IIF Profile L2
0x64 AAC IIF Profile L3
0x65 AAC IIF Profile L4
0x66 AAC IIF Profile L5
0x67 AAC IIF Profile L6
0x68 AAC IIF Profile L7
0x69 - 0x6F reserved for ISO/IEC 14496-3 -
0x70 - 0x7F reserved for ISO/IEC 23003-3 -

Update numbering of Table 1.19 to Table 1.20, after “break;” for “case 46:” add the following:

© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
case 47:
iif_specific_config(samplingFrequencyIndex);
break;
case 64: … case 95:
UsacAotSpecificConfig(audioObjectType);
break;
After 1.6.2.1.22, add the following:
1.6.2.1.23  iif_specific_config
Defined in subpart 4.
1.6.2.1.24  UsacAotSpecificConfig
Defined in ISO/IEC 23003-3.
Update numbering of Table 1.21 to 1.22 and add the following at the end of Table:
47 AAC IIF ISO/IEC 14496-3 Subpart 4 see subclause 1.6.2.2.2.6

After 1.6.2.2.2.5, add the following:
1.6.2.2.2.6  AAC IIF
One top level payload (iif_access_unit()) is mapped into one access unit. A sequence of access units forms
one elementary stream.
Update numbering of Table 1.22 and following tables accordingly.

In Annex 1.C, replace “ISO/IEC14496-5 :2001, Information technology — Coding of audio-visual objects —
Part 5: Reference software” with:
ISO/IEC 14496-35, Information technology — Coding of audio-visual objects — Part 35: Audio reference
software
In 4.4.2.7, Table 4.59 “Syntax of extension_payload()”, after “return uniDrc();”, add the following:
case EXT_AUTH_DATA:
fill_nibble; /* shall be ‘0000’ */ 4 uimsbf
return auth_extension();
case EXT_ADD_TYPES:
extension_type_add; 4 uimsbf
extension_type = 0xF + extension_type_add;
switch( extension_type ) {
default:
© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
for (i=0; i<8*(cnt-1); i++) {
other_bits[i]; 1 uimsbf
}
return cnt;
}
For the base document ISO/IEC 14496-3:2019, before application of the present amendment, in sequential order,
Renumber Tables 4.87 to 4.143 as Tables 4.108 to 4.164.
Renumber Tables 4.144 to 4.165 as Tables 4.180 to 4.201.
Renumber Tables 4.166 to 4.201 as Tables 4.214 to 4.249.

Add the following after 4.4.2.9:
4.4.2.10  Payloads for the audio object type AAC IIF
The following table shows an overview of syntax elements for payloads for the audio object type AAC IIF.
Syntax Element Description
iif_access_unit() Table 4.87
iif_block() Table 4.88
iif_block_header() Table 4.89
iif_block_payload() Table 4.90
iif_audio_payload() Table 4.91
iif_metadata_payload() Table 4.92
metadata_section() Table 4.93
md_size(is_bytes) Table 4.94
iif_metadata_frame() Table 4.95
iif_config_update() Table 4.96
iif_block_footer() Table 4.97
wtdav_data() Table 4.98
lsb_plane_data() Clause 4.6.21.8.7.2
single_channel_element_iif() Table 4.99
pred_data() Table 4.100
channel_pair_element_iif() Table 4.101
individual_channel_stream_iif() Table 4.102
hgr_section_data() Table 4.103
gr_data() Table 4.104
icp_data() Table 4.105
lms_data() Table 4.106
zlsb_data() Table 4.107
© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
Table 4.87 — Syntax of iif_access_unit()
Syntax No. of bits Mnemonic
iif_access_unit()
{
while (bits_to_decode() > 23) {
iif_block();
}
}
Table 4.88 — Syntax of iif_block()
Syntax No. of bits Mnemonic
iif_block()
{
iif_block_header();
iif_block_payload();
iif_block_footer();
}
Table 4.89 — Syntax of iif_block_header()
Syntax No. of bits Mnemonic
iif_block_header()
{
frame_counter; 4 uimsbf
block_id; 5 uimsbf
block_priority; 2 uimsbf
block_size; 11 uimsbf
b_block_protected; 1 uimsbf
reserved; 1 uimsbf
block_bytes_left = block_size;
if (block_size == 0x7ff) {
ext_block_size = 0;
ext_blk_size_loop_cnt = 0;
b_more_bits = 1;
while (0 != b_more_bits) {
if (ext_blk_size_loop_cnt < 2) {
block_size_extension; 7 uimsbf
b_more_bits; 1 uimsbf
ext_block_size <<= 7;
} else {
block_size_extension; 8 uimsbf
b_more_bits = 0;
ext_block_size <<= 8;
}
ext_block_size += block_size_extension;
ext_blk_size_loop_cnt += 1;
}
© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
TTabablele 4 4.8899 ((ccoonnttiinnueuedd))
Syntax No. of bits Mnemonic
block_size += ext_block_size + ext_blk_size_loop_cnt;
block_bytes_left = block_size – ext_blk_size_loop_cnt;
}
if (b_block_protected) {
block_bytes_left = block_bytes_left – 2;
}
}
Table 4.90 — Syntax of iif_block_payload()
Syntax No. of bits Mnemonic
iif_block_payload()
{
/* Config Update */
b_use_default_config; 1 uimsbf
if (!b_use_default_config) {
b_config_update_inband; 1 uimsbf
if (b_config_update_inband) {
iif_config_update(0);
} else {
dynamic_config_upd_idx_minus1; 3 uimsbf
}
}
iif_metadata_payload();
/* Audio Data */
if (audio_signals_in_source_block[block_id] > 0) {
samplingFrequency = block_sampling_rate[block_id];
iif_audio_payload();
}
byte_alignment();
}
Table 4.91 — Syntax of iif_audio_payload()
Syntax No. of bits Mnemonic
iif_audio_payload()
{
iif_lossless_enabled =
((block_priority == 0 && b_block_priority0_is_lossless[block_id] == 1) ||
(block_priority == 1 && b_block_priority1_is_lossless[block_id] == 1));

b_iif_lossless_mode = b_channel_permute = b_permute_cpe_channels = 0;

© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
TaTabbllee 4 4.9191 ((ccoonnttiinnueuedd))
Syntax No. of bits Mnemonic
b_lsb_data = gr_par_offset = 0;

if (iif_lossless_enabled) {
b_iif_lossless_mode; 1 uimsbf
if (b_iif_lossless_mode) {
if (audio_signals_in_source_block[block_id] > 1) {
b_channel_permute; 1 uimsbf
if (b_channel_permute == 1) {
b_permute_cpe_channels; 1 uimsbf
ch_bits = ceil(log2(audio_signals_in_source_block[block_id]));
}
}
b_lsb_data; 1 uimsbf
gr_par_offset; 3 uimsbf
}
}
n_channels = 0;
while (n_channels < audio_signals_in_source_block[block_id])
{
b_element_is_cpe; 1 uimsbf
if (b_element_is_cpe == 0) {
single_channel_element_iif(
n_channels,
b_iif_lossless_mode,
b_channel_permute,
b_lsb_data);
n_channels += 1;
} else {
channel_pair_element_iif(
n_channels,
b_iif_lossless_mode,
b_channel_permute + b_permute_cpe_channels,
b_lsb_data);
n_channels += 2;
}
}
}
© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
Table 4.92 — Syntax of iif_metadata_payload()
Syntax No. of bits Mnemonic
iif_metadata_payload(num_block_bits_left)
{
num_bits_left = num_block_bits_left;
num_metadata_sections = 0;
metadata_section_entry[num_metadata_sections] = -1;

if (use_explicit_metadata_signalling[block_id]) {
b_more_md_sections; 1 uimsbf
while (b_more_md_sections) {
md_type_idx; 4 uimsbf
metadata_section_entry[num_metadata_sections] =

md_entry[block_id][md_type_idx];
num_metadata_sections += 1;
metadata_section_entry[num_metadata_sections] = -1;
b_more_md_sections; 1 uimsbf
}
} else {
for (m=0; m b_metadata_present; 1 uimsbf
if (b_metadata_present) {
metadata_section_entry[num_metadata_sections] =

md_entry[block_id][m];
num_metadata_sections += 1;
metadata_section_entry[num_metadata_sections] = -1;
}
}
}
if (num_metadata_sections > 0) {
for (s=0; s num_bits_read = metadata_section();
num_bits_left -= num_bits_read;
}
}
}
© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
Table 4.93 — Syntax of metadata_section()
Syntax No. of bits Mnemonic
metadata_section(b_metadata_framing, b_metadata_is_byte_aligned)
{
if (b_metadata_framing) {
num_metadata_chunks_in_section_minus1; max_
uimsbf
chunks_bits
for (i = 0; i < num_metadata_chunks_in_section_minus1 + 1; ++i) {
max_
chunk_number; spreading_ uimsbf
bits
if (chunk_number == 0) {
sample_offset_from_audio; 12 uimsbf
max_
num_chunks_in_metadata_frame_minus1; spreading_ uimsbf
bits
b_audio_time_code_exists; 1 uimsbf
if (b_audio_time_code_exists) {
audio_timestamp_nanosecs; 64 uimsbf
}
b_original_audio_time_code_exists; 1 uimsbf
if (b_original_audio_time_code_exists) {
original_audio_timestamp_nanosecs; 64 uimsbf
}
}
chunk_len_bytes = md_size(true) >> 3;
for (i = 0; i < chunk_len_bytes; ++i) {
chunk_byte; 8 uimsbf
chunk_buffer[md_entry].push_back(chunk_byte);
}
if (chunk_number == num_chunks_in_metadata_frame_minus1) {
iif_metadata_frame(metadata_type, chunk_buffer.size());
}
}
} else {
n_metadata_bits = md_size(b_metadata_is_byte_aligned);
iif_metadata_frame(metadata_type, n_metadata_bits);
}
return n_metadata_bits;
}
Note 1: chunk_buffer.push_back() inserts one byte at the end of the buffer
Note 2: chunk_buffer.size() returns the size of the buffer in bytes

© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
Table 4.94 — Syntax of md_size()
Syntax No. of bits Mnemonic
md_size(is_bytes)
{
md_size_num_bits_base = 10;
md_size_num_bits_ext = 18;
if (is_bytes) {
md_size_num_bits_base = 7;
md_size_num_bits_ext = 15;
}
md_size_
md_size_value; num_bits_ uimsbf
base
if (md_size_value == 0) {
md_size_
ext_md_size_value; num_bits_ uimsbf
ext
md_size_value = (1 << md_size_num_bits_base) + ext_md_size_value;
}
if (is_bytes) {
md_size_value = md_size_value * 8;
}
return md_size_value;
}
Table 4.95 — Syntax of iif_metadata_frame()
Syntax No. of bits Mnemonic
iif_metadata_frame(_md_type, _nbits)
{
switch (_md_type) {
case METADATA_TYPE_AUTH:
auth_extension();
break;
default:
unknown_metadata; _nbits uimsbf
break;
}
}
© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
Table 4.96 — Syntax of iif_config_update()
Syntax No. of bits Mnemonic
iif_config_update(_cfg)
{
for (p = 0; p < num_audio_presentations; p++) {
if (audio_presentation_type[p] ==

AUDIO_PRESENTATION_TYPE_CHANNELS) {
b_active_channel_config_is_super; 1 uimsbf
if (b_active_channel_config_is_super) {
active_channel_config_idx[_cfg][p] = 0;
} else {
active_channel_config_idx_minus1; 3 uimsbf
active_channel_config_idx[_cfg][p] =

active_channel_config_idx_minus1 + 1;
}
active_channel_mode[_cfg][p] =
channel_config_set_channel_mode
[active_channel_config_idx[_cfg][p]];
active_channel_mask[_cfg][p] =
channel_config_set_channel_mask
[active_channel_config_idx[_cfg][p]];

if (_cfg == 0) {
b_active_channel_config_change[_cfg][p]; 1 uimsbf
if (b_active_channel_config_change[_cfg][p]) {
next_channel_config_sample_offset_minus1; 10 uimsbf
next_channel_config_sample_offset[_cfg][p] =

next_channel_config_sample_offset_minus1 + 1;

b_next_channel_config_is_super; 1 uimsbf
if (b_next_channel_config_is_super) {
next_channel_config_idx[_cfg][p] = 0;
} else {
next_channel_config_idx_minus1; 3 uimsbf
next_channel_config_idx[_cfg][p] =

next_channel_config_idx_minus1 + 1;
}
next_channel_mode[_cfg][p] =
channel_config_set_channel_mode
[next_channel_config_idx[_cfg][p]];
next_channel_mask[_cfg][p] =
channel_config_set_channel_mask
[next_channel_config_idx[_cfg][p]];
}
}
}
}
© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
TTabablele 4 4.9966 ((ccoonnttiinnueuedd))
Syntax No. of bits Mnemonic
if (num_target_devices > 0) {
/* init with defaults */
for (d=0; d for (s=0; s audio_signal_role[_cfg][d][s] = default_audio_signal_role[d][s];
audio_signal_gain[_cfg][d][s] = default_audio_signal_gain[d][s];
audio_signal_delay[_cfg][d][s] =

default_audio_signal_delay[d][s];
}
}
/* override */
b_override_defaults; 1 uimsbf
if (b_override_defaults == 1) {
for (d=0; d if (_cfg >0 || device_address_mask[block_id]&(1< /* only if parent block is addressed to this device! */
b_override_default_role_for_device; 1 uimsbf
if (b_override_default_role_for_device) {
for (s=0; s b_signal_connected; 1 uimsbf
if (b_signal_connected == 1) {
audio_signal_role[_cfg][d][s]; 3 uimsbf
} else {
audio_signal_role[_cfg][d][s] = -1;
}
}
}
b_override_default_params_for_device; 1 uimsbf
if (b_override_default_params_for_device) {
for (s=0; s if (audio_signal_role[_cfg][d][s] >= 0) {
b_override_default_gain; 1 uimsbf
if (b_override_default_gain) {
b_reset_gain; 1 uimsbf
if (b_reset_gain) {
audio_signal_gain[_cfg][d][s] = 0;
} else {
gain_code; 5 uimsbf
}
}
b_override_default_delay; 1 uimsbf
if (b_override_default_delay) {
b_relative_delay; 1 uimsbf
© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
TTabablele 4 4.9966 ((ccoonnttiinnueuedd))
Syntax No. of bits Mnemonic
if (b_relative_delay == 1) {
rel_delay_code; 7 uimsbf
} else {
delay_code; 12 uimsbf
audio_signal_delay[_cfg][d][s] =

4*delay_code;
}
}
}
}
}
}
}
}
}
if (_cfg == 0) {
if (b_enable_block_tags) {
b_block_tags_update; 1 uimsbf
if (b_block_tags_update) {
iif_block_tags_info(block_id);
iif_block_zones_info(block_id);
}
}
}
}
Table 4.97 — Syntax of iif_block_footer()
Syntax No. of bits Mnemonic
iif_block_footer()
{
block_bytes_
block_fill;
left * 8
if (b_block_protected) {
block_crc; 16 uimsbf
}
}
Table 4.98 — Syntax of wtdav_data()
Syntax No. of bits Mnemonic
wtdav_data()
{
numBits1 = pcmWordLength + 1;
numBits2 = pcmWordLength;
frame_length_aux = floor(window_length / 2);

© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
TTabablele 4 4.9988 ((ccoonnttiinnueuedd))
Syntax No. of bits Mnemonic
tdaBorderLeft = frame_length_aux / 2;
tdaBorderRight = tdaBorderLeft;
if (b_window_switching) {
window_shape; 1 uimsbf
previous_window_shape; 1 uimsbf
if (previous_window_shape == 1) {
tdaBorderRight = frame_length_aux – floor(frame_length_aux / 8);
}
if (window_shape == 1) {
tdaBorderLeft = floor(frame_length_aux / 8);
}
} else if (iif_window_shape == 1) {
tdaBorderRight = frame_length_aux – floor(frame_length_aux / 8);
tdaBorderLeft = floor(frame_length_aux / 8);
}
T = 0;
if (toggle_frame) T = 1;
for (s = 0; s < frame_length_aux; s++) {
if (s < tdaBorderLeft || s >= tdaBorderRight) {
wtdaSignal[T + s] = (-1) * tmp; numBits1 tcimsbf
} else {
wtdaSignal[T + s] = (-1) * tmp; numBits2 tcimsbf
}
}
if (toggle_frame) { /* see 4.6.21.8.13.3 */
wtdaSignal[0] = wtda_toggle_sample; numBits1 tcimsbf
}
}
Table 4.99 — Syntax of single_channel_element_iif()
Syntax No. of bits Mnemonic
single_channel_element_iif(
ch_offset,
b_iif_lossless_mode,
ch_permute_mode,
b_lsb_data)
{
wtdav_mode[0] = 0;
iif_audio_bus_offset_rel[0] = ch_offset;
num_zlsb_left = num_zlsb_right = 0;

if (b_iif_lossless_mode) {
zlsb_data();
wtdav_mode[0]; 1 uimsbf
if (ch_permute_mode) {
© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
TTabablele 4 4.9999 ((ccoonnttiinnueuedd))
Syntax No. of bits Mnemonic
iif_audio_bus_offset_rel[0]; ch_bits uimsbf
}
}
if (wtdav_mode[0]) {
wtdav_data();
} else {
num_prev_channels = ch_offset;
individual_channel_stream_iif(0, b_iif_lossless_mode, b_lsb_data, 0);
}
}
Table 4.100 — Syntax of pred_data()
Syntax No. of bits Mnemonic
pred_data(max_sfb)
{
pred_all; 1 uimsbf
if (pred_all == 0) {
for (sfb = 0; sfb < max_sfb; sfb++) {
pred_used[sfb]; 1 uimsbf
}
} else {
for (sfb = 0; sfb < max_sfb; sfb++) {
pred_used[sfb] = 1;
}
}
common_alpha_present; 1 uimsbf
if (common_alpha_present) {
index[alpha_q_common]; 6 uimsbf
if (alpha_q_common != 0) {
quant_step_size; 1 uimsbf
common_pred_dir_present = 1;
common_pred_dir; 1 uimsbf
} else {
quant_step_size = 0;
common_pred_dir_present = 1;
common_pred_dir = 0;
}
} else {
common_pred_dir_present; 1 uimsbf
if (common_pred_dir_present) {
common_pred_dir; 1 uimsbf
}
}
© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
TTabablele 4 4.110000 ((ccoonnttiinnueuedd))
Syntax No. of bits Mnemonic
is_first_pred_band = 1;
for (sfb = 0; sfb < max_sfb; sfb++) {
if (pred_used[sfb]) {
if (common_alpha_present == 0) {
if (is_first_pred_band == 1) {
is_first_pred_band = 0;
index[alpha_q[sfb]]; 6 uimsbf
} else {
hcod_sf[dpcm_alpha_q[sfb]]; 1.19 vlclbf
}
} else {
alpha_q[sfb] = alpha_q_common;
}
if (common_pred_dir_present == 0) {
if (alpha_q[sfb] != 0) {
pred_dir[sfb]; 1 uimsbf
} else {
pred_dir[sfb] = 0;
}
} else {
pred_dir[sfb] = common_pred_dir;
}
}
}
}
Table 4.101 — Syntax of channel_pair_element_iif()
Syntax No. of bits Mnemonic
channel_pair_element_iif(
ch_offset,
b_iif_lossless_mode,
ch_permute_mode,
b_lsb_data)
{
common_window = wtdav_mode[0] = wtdav_mode[1] = 0;
chan_flip_flag = 0;
iif_audio_bus_offset_rel[0] = ch_offset;
iif_audio_bus_offset_rel[1] = ch_offset + 1;
num_zlsb_left[0] = num_zlsb_right[0] = 0;
num_zlsb_left[1] = num_zlsb_right[1] = 0;

if (b_iif_lossless_mode) {
zlsb_data(0);
zlsb_data(1);
© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
TTabablele 4 4.110011 ((ccoonnttiinnueuedd))
Syntax No. of bits Mnemonic
for (ch = 0; ch < 2; ch++) {
wtdav_mode[ch]; 1 uimsbf
}
if (ch_permute_mode > 0) {
iif_audio_bus_offset_rel[0]; ch_bits uimsbf
if (ch_permute_mode > 1) {
iif_audio_bus_offset_rel[1]; ch_bits uimsbf
} else {
iif_audio_bus_offset_rel[1] = iif_audio_bus_offset_rel[0] + 1;
}
}
if (ch_permute_mode < 2) {
if (wtdav_mode[0] == 0 && wtdav_mode[1] == 0) {
chan_flip_flag; 1 uimsbf
if (chan_flip_flag) {
tmp = iif_audio_bus_offset_rel[0];
iif_audio_bus_offset_rel[0] = iif_audio_bus_offset_rel[1];
iif_audio_bus_offset_rel[1] = tmp;
}
}
}
}
if (wtdav_mode[0] == 0 && wtdav_mode[1] == 0) {
common_window; 1 uimsbf
}
ms_mask_present = 0;
if (common_window) {
if (b_window_switching) {
window_shape; 1 uimsbf
}
if (b_iif_lossless_mode) {
max_sfb = num_swb_long_window;
} else {
max_sfb; 6 uimsbf
}
ms_mask_present; 2 uimsbf
if (ms_mask_present == 1) {
for (sfb = 0; sfb < max_sfb; sfb++) {
ms_used[sfb]; 1 uimsbf
}
} else if (b_iif_lossless_mode && ms_mask_present == 3) {

© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
TTabablele 4 4.110011 ((ccoonnttiinnueuedd))
Syntax No. of bits Mnemonic
pred_data(max_sfb);
}
}
for (ch = 0; ch < 2; ch++) {
if (wtdav_mode[ch]) {
wtdav_data();
} else {
num_prev_channels = ch_offset + ch;
individual_channel_stream_iif(
common_window, b_iif_lossless_mode, b_lsb_data,
ms_mask_present);
}
}
}
Table 4.102 — Syntax of individual_channel_stream_iif()
Syntax No. of bits Mnemonic
individual_channel_stream_iif(
common_window, b_iif_lossless_mode, b_lsb_data,
ms_mask_present)
{
if (b_iif_lossless_mode) {
if (b_lsb_data) {
global_gain; 5 uimsbf
}
} else {
global_gain; 8 uimsbf
}
if (common_window == 0) {
if (b_window_switching) {
window_shape; 1 uimsbf
}
if (b_iif_lossless_mode) {
max_sfb = num_swb_long_window;
} else {
max_sfb; 6 uimsbf
}
}
section_data();
if (b_iif_lossless_mode == 0 || b_lsb_data) {
if (b_lsb_data) {
© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
TTabablele 4 4.110022 ((ccoonnttiinnueuedd))
Syntax No. of bits Mnemonic
all_sf_same; 1 uimsbf
} else {
all_sf_same = 0;
}
if (all_sf_same == 0) {
scale_factor_data();
}
}
tns_data_present; 1 uimsbf
if (tns_data_present) {
tns_data();
}
spectral_data();
if (b_iif_lossless_mode) {
if (ms_mask_present == 0 || ms_mask_present == 2) {
lms_data();
icp_data();
} else {
icpMode = lmsFlag = lmsCcFlag = 0;
}
if (b_lsb_data) {
lsb_plane_data(x_rescal); /* see 4.6.21.8.7.2 */
}
if (toggle_frame) { /* see 4.6.21.8.13.3 */
numBits = pcmWordLength + 1;
wtda_toggle_sample; numBits tcimsbf
}
}
}
Table 4.103 — Syntax of hgr_section_data()
Syntax No. of bits Mnemonic
hgr_section_data()
{
cbi[0]; 5 uimsbf
prev_cbi = cbi[0];
for (sfb = 1; sfb < max_sfb; sfb++) {
hcod_sf[dpcm_cbi[sfb]]; 1.19 vlclbf
cbi[sfb] = prev_cbi + dpcm_cbi[sfb] – 60;
prev_cbi = cbi[sfb];
}
}
© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
Table 4.104 — Syntax of gr_data()
Syntax No. of bits Mnemonic
gr_data(grPar)
{
grQuot = 0;
while (unaryCodeBit == 1) { 1 uimsbf
grQuot++;
}
grRem; grPar uimsbf
val = (grQuot << grPar);
val += grRem;
if (val > 0) {
if (signBit == 1) { 1 uimsbf
val = -val;
}
}
return val;
}
Table 4.105 — Syntax of icp_data()
Syntax No. of bits Mnemonic
icp_data()
{
icpMode = 0;
if (num_prev_channels > 0) {
icpMode; 2 uimsbf
if (icpMode > 0) {
icpRefChan = 0;
if (num_prev_channels > 1) {
refChBits = ceil(log2(num_prev_channels));
icpRefChan; refChBits uimsbf
}
if (icpMode == 1) {
icpPredCoef = icpPredCoefIndex – 128; 8 uimsbf
} else {
numPredCoeffs = (icpMode == 2) ? (max_sfb / 2) : max_sfb;
prevCoef = 0;
for (cpb = 0; cpb < numPredCoeffs; cpb++) {
hcod_sf[dpcm_icpcoeff[icpb]]; 1.19 vlclbf
icpPredCoefsArray[cpb] = prevCoef +

dpcm_icpcoeff[cpb] – 60;
prevCoef = icpPredCoefsArray[cpb];
}
}
© ISO/IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/FDAM 1:2026(en)
TTabablele 4 4.110055 ((ccoonnttiinnueuedd))
Syntax No. of bits Mnemonic
}
}
}
Table 4.106 — Syntax of lms_data()
Syntax No. of bits Mnemonic
lms_data()
{
lmsFlag; 1 uimsbf
lmsCcFlag = 0;
if (num_prev_channels > 0) {
lmsCcFlag; 1 uimsbf
}
if (lmsFlag == 1) {
lmsOrderOver2Minus1; 3 uimsbf
lmsOrder = (lmsOrderOver2Minus1 + 1) << 1;
} else {
lmsOrder = 0;
}
}
Table 4.107 — Syntax of zlsb_data()
Syntax No. of bits Mnemonic
zlsb_data()
{
num_zlsb_left = num_zlsb_right = 0;
any_zero_lsbs; 1 uimsbf
if (any_zero_lsbs) {
num_zlsb_left; 4 uimsbf
if (num_zlsb_left == 0) {
...

ISO/IEC 14496-3:2019/FDAMFDAmd 1:2026(en)
ISO/IEC JTC1JTC 1/SC 29/WG 6
Secretariat: JISC
Date: 2026-06-1907-09
Information technology — Coding of audio-visual objects —
Part 3:
Audio
Amendment AMENDMENT 1: Media authenticity and immersive
interchange format
FDIS stage
ISO/IEC 14496-3:2019/DAM 1:2026(en)
© ISO/IEC 20252026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
EmailE-mail: [e-mail]
Website: www.iso.orgwww.iso.org
Published in Switzerland
© ISO/IEC 2026 – All rights reserved
iii
ISO #####-#:####(X)
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.
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/directiveswww.iso.org/directives or
www.iec.ch/members_experts/refdocswww.iec.ch/members_experts/refdocs).
ISO and IEC draw attention to the possibility that the implementation of this document may involve the
use of (a) patent(s). ISO and IEC take no position concerning the evidence, validity or applicability of any
claimed patent rights in respect thereof. As of the date of publication of this document, ISO and IEC
[had/had not] received notice of (a) patent(s) which may be required to implement this document.
However, implementers are cautioned that this may not represent the latest information, which may be
obtained from the patent database available at www.iso.org/patents and
https://patents.iec.ch.www.iso.org/patents and https://patents.iec.ch. ISO and IEC shall not be held
responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, 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
www.iso.org/iso/foreword.html.www.iso.org/iso/foreword.html. In the IEC, see
www.iec.ch/understanding-standardswww.iec.ch/understanding-standards.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information.
A list of all parts in the ISO/IEC 14496 series can be found on the ISO and IEC websites.
Any feedback or questions on this document should be directed to the user’s national standards body.
A complete listing of these bodies can be found at
www.iso.org/members.htmlwww.iso.org/members.html and www.iec.ch/national-
committeeswww.iec.ch/national-committees.
.
iv © ISO ###w – All rights reserved

ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)
© ISO/IEC 2026 – All rights reserved
v
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)
Information technology — Coding of audio-visual objects —
Part 3:
Audio
AMENDMENT 1: Media authenticity and immersive
interchange format
Replace T.130 and T.131 with the following:
T.130
NCC
number of considered channels
number of channels represented by the elements SCE, independently switched CCE and
CPE, i.e. once the number of SCEs plus once the number of independently switched CCEs plus twice
the number of CPEs.
Note 1 to entry: This number is used to derive the required decoder input buffer size (see subpart 4,
subclause 4.5.3.1).
Add the following at the end of Section 1.2:
IETF RFC 3986, Uniform Resource Identifier (URI): Generic Syntax
IETF RFC 9562, Universally Unique IDentifiers (UUIDs)
ISO/IEC 23091-3, Information technology — Coding-independent code-points — Part 3: Audio

Add the following line in Section 1.4.7 below the line defining “uimsbf” and before the line
defining “vlclbf”:
tcimsbf Two’s complement integer, most significant (sign) bit first.

Add the following lines at the end of Table 1.1:
4 A
7 A
C
I
I
© ISO/IEC 2026 – All rights reserved
ISO #####-#:####(X/IEC 14496-3:2019/FDAmd 1(en)
F
a
4 R
8 e
- s
6 e
3 r
v
e
d
f
o
r
-
6 R
4 e
- s
9 e
5 r
v
e
d
f
o
r
-
a Details on syntax elements and tools are defined in 1.5.1.2.43.

At the end of 1.5.1.2, add the following:
1.5.1.2.43  AAC - Immersive Interchange Format (IIF) object type
The AAC IIF object type contains the codec defined in 4.6.21.4.6.21.
It is based on the ER AAC LD object type and contains the tools and modules of the ER AAC LD
object type according to Table 1.1 except for the AAC ER tools, the ER payload syntax module, the
EP tool, the LTP tool and pulse data.
It contains all characteristics, tools, modules, processing steps and syntax elements defined in
4.6.21, 4.4.2.10,4.6.21, 4.4.2.10, 4.5.2.18 and Annex 4.C.
8 © ISO ###w /IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)

At the end of 1.5.2.1, add the following:
16. The Immersive Interchange Profile contains the audio object type 47 (AAC IIF).

16.  The Immersive Interchange Profile contains the audio object type 47 (AAC IIF).

Replace Table 1.3 with the following:
Table 1.3 — Audio Profiles definition
M L H A L I
o o ig L o m
b w h S w m
i D D Si D e
H
l e ef m el r
H i
H e l i p a s
i g
i A a n le y i
S L g h
g u y it P A v
S c o h E
h d A i r A e
S y a w N E f
Q i A o o C I
p n l D a f f
M u o C n fi v n
e t a e t f i
ai a I P A le 2 t
O e h b l u A i c
n l n r A P e
b c e l a r A c i
A i t o C r r
je h ti e y al C i e
u t e f P o c
ct A c A A A P e n
d y r i r fi h
T Audio u A u u u r n c
i A n l o le a
y Object Type d u d d d o c y
o u e e fi n
p i d i i i f y A
P d t le g
e o i o o o i A A
r i w e
I P o P P P l A C
o o o P
D r P r r r e C v
fi P r r
o r o o o P 2
le r k o
fi o f f fi r P
o i f
le fi i i le o r
f n i
le l l f o
i g l
e e i f
l P e
l i
e r
e l
o
e
f
i
l
e
0 Null
1 AAC main    X   X
2 AAC LC   X X X  X  X X X  X
© ISO/IEC 2026 – All rights reserved
ISO #####-#:####(X/IEC 14496-3:2019/FDAmd 1(en)
M L H A L I
o o ig L o m
b w h S w m
i D D Si D e
H
l e ef m el r
H i
H e l i p a s
i g
i A a n le y i
S L g h
g u y it P A v
S c o h E
h d A i r A e
S y a w N E f
Q i A o o C I
p n l D a f f
M u o C n fi v n
e t a e t f i
ai a I P A le 2 t
O e h b l u A i c
n l n r A P e
b c e l a r A c i
A i t o C r r
je h ti e y al C i e
u t e f P o c
ct A c A A A P e n
d y r i r fi h
T Audio u A u u u r n c
i A n l o le a
y Object Type d u d d d o c y
o u e e fi n
p i d i i i f y A
P d t le g
e o i o o o i A A
r i w e
I P o P P P l A C
o o o P
D r P r r r e C v
fi P r r
o r o o o P 2
le r k o
fi o f f fi r P
o i f
le fi i i le o r
f n i
le l l f o
i g l
e e i f
l P e
l i
e r
e l
o
e
f
i
l
e
3 AAC SSR    X   X
4 AAC LTP   X X X  X
5 SBR          X X
6 AAC Scalable   X X X  X
7 TwinVQ   X X   X
8 CELP X  X X X X X
9 HVXC X  X X  X X
1 (reserved)
1 (reserved)
1 TTSI X X X X  X X
1 Main  X  X
3 synthetic
10 © ISO ###w /IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)
M L H A L I
o o ig L o m
b w h S w m
i D D Si D e
H
l e ef m el r
H i
H e l i p a s
i g
i A a n le y i
S L g h
g u y it P A v
S c o h E
h d A i r A e
S y a w N E f
Q i A o o C I
p n l D a f f
M u o C n fi v n
e t a e t f i
ai a I P A le 2 t
O e h b l u A i c
n l n r A P e
b c e l a r A c i
A i t o C r r
je h ti e y al C i e
u t e f P o c
ct A c A A A P e n
d y r i r fi h
T Audio u A u u u r n c
i A n l o le a
y Object Type d u d d d o c y
o u e e fi n
p i d i i i f y A
P d t le g
e o i o o o i A A
r i w e
I P o P P P l A C
o o o P
D r P r r r e C v
fi P r r
o r o o o P 2
le r k o
fi o f f fi r P
o i f
le fi i i le o r
f n i
le l l f o
i g l
e e i f
l P e
l i
e r
e l
o
e
f
i
l
e
1 Wavetable  X X
4 synthesis * *
1 General MIDI  X X
5 * *
1 Algorithmic  X X
6 Synthesis * *
and Audio
FX
1 ER AAC LC     X  X X
(reserved)
1 ER AAC LTP     X  X
2 ER AAC     X  X X
0 Scalable
© ISO/IEC 2026 – All rights reserved
ISO #####-#:####(X/IEC 14496-3:2019/FDAmd 1(en)
M L H A L I
o o ig L o m
b w h S w m
i D D Si D e
H
l e ef m el r
H i
H e l i p a s
i g
i A a n le y i
S L g h
g u y it P A v
S c o h E
h d A i r A e
S y a w N E f
Q i A o o C I
p n l D a f f
M u o C n fi v n
e t a e t f i
ai a I P A le 2 t
O e h b l u A i c
n l n r A P e
b c e l a r A c i
A i t o C r r
je h ti e y al C i e
u t e f P o c
ct A c A A A P e n
d y r i r fi h
T Audio u A u u u r n c
i A n l o le a
y Object Type d u d d d o c y
o u e e fi n
p i d i i i f y A
P d t le g
e o i o o o i A A
r i w e
I P o P P P l A C
o o o P
D r P r r r e C v
fi P r r
o r o o o P 2
le r k o
fi o f f fi r P
o i f
le fi i i le o r
f n i
le l l f o
i g l
e e i f
l P e
l i
e r
e l
o
e
f
i
l
e
2 ER TwinVQ       X X
2 ER BSAC       X X
2 ER AAC LD      X X X    X   X
2 ER CELP     X X X
2 ER HVXC      X X
ER HILN       X
2 ER       X
7 Parametric
2 SSC
12 © ISO ###w /IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)
M L H A L I
o o ig L o m
b w h S w m
i D D Si D e
H
l e ef m el r
H i
H e l i p a s
i g
i A a n le y i
S L g h
g u y it P A v
S c o h E
h d A i r A e
S y a w N E f
Q i A o o C I
p n l D a f f
M u o C n fi v n
e t a e t f i
ai a I P A le 2 t
O e h b l u A i c
n l n r A P e
b c e l a r A c i
A i t o C r r
je h ti e y al C i e
u t e f P o c
ct A c A A A P e n
d y r i r fi h
T Audio u A u u u r n c
i A n l o le a
y Object Type d u d d d o c y
o u e e fi n
p i d i i i f y A
P d t le g
e o i o o o i A A
r i w e
I P o P P P l A C
o o o P
D r P r r r e C v
fi P r r
o r o o o P 2
le r k o
fi o f f fi r P
o i f
le fi i i le o r
f n i
le l l f o
i g l
e e i f
l P e
l i
e r
e l
o
e
f
i
l
e
2 PS           X
3 MPEG
0 Surround
3 (escape)
3 Layer-1
3 Layer-2
3 Layer-3
3 DST
3 ALS              X
© ISO/IEC 2026 – All rights reserved
ISO #####-#:####(X/IEC 14496-3:2019/FDAmd 1(en)
M L H A L I
o o ig L o m
b w h S w m
i D D Si D e
H
l e ef m el r
H i
H e l i p a s
i g
i A a n le y i
S L g h
g u y it P A v
S c o h E
h d A i r A e
S y a w N E f
Q i A o o C I
p n l D a f f
M u o C n fi v n
e t a e t f i
ai a I P A le 2 t
O e h b l u A i c
n l n r A P e
b c e l a r A c i
A i t o C r r
je h ti e y al C i e
u t e f P o c
ct A c A A A P e n
d y r i r fi h
T Audio u A u u u r n c
i A n l o le a
y Object Type d u d d d o c y
o u e e fi n
p i d i i i f y A
P d t le g
e o i o o o i A A
r i w e
I P o P P P l A C
o o o P
D r P r r r e C v
fi P r r
o r o o o P 2
le r k o
fi o f f fi r P
o i f
le fi i i le o r
f n i
le l l f o
i g l
e e i f
l P e
l i
e r
e l
o
e
f
i
l
e
3 SLS             X
3 SLS non-core
3 ER AAC ELD               X
4 SMR Simple
4 SMR Main
USAC
4 SAOC
4 LD MPEG               X
4 Surround
14 © ISO ###w /IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)
M L H A L I
o o ig L o m
b w h S w m
i D D Si D e
H
l e ef m el r
H i
H e l i p a s
i g
i A a n le y i
S L g h
g u y it P A v
S c o h E
h d A i r A e
S y a w N E f
Q i A o o C I
p n l D a f f
M u o C n fi v n
e t a e t f i
ai a I P A le 2 t
O e h b l u A i c
n l n r A P e
b c e l a r A c i
A i t o C r r
je h ti e y al C i e
u t e f P o c
ct A c A A A P e n
d y r i r fi h
T Audio u A u u u r n c
i A n l o le a
y Object Type d u d d d o c y
o u e e fi n
p i d i i i f y A
P d t le g
e o i o o o i A A
r i w e
I P o P P P l A C
o o o P
D r P r r r e C v
fi P r r
o r o o o P 2
le r k o
fi o f f fi r P
o i f
le fi i i le o r
f n i
le l l f o
i g l
e e i f
l P e
l i
e r
e l
o
e
f
i
l
e
4 SAOC-DE
4 Audio Sync
4 AAC IIF                X
*) Subset of Main Synthetic
0 Null
1 AAC main  X  X
2 AAC LC  X X X X X X X X
3 AAC SSR  X  X
4 AAC LTP  X X X X
5 SBR     X X
6 AAC Scalable  X X X X
7 TwinVQ  X X  X
8 CELP X X X X X X
9 HVXC X X X X X
10 (reserved)
11 (reserved)
12 TTSI X X X X X X
© ISO/IEC 2026 – All rights reserved
ISO #####-#:####(X/IEC 14496-3:2019/FDAmd 1(en)
13 Main synthetic X X
14 Wavetable synthesis X* X*
15 General MIDI X* X*
16 Algorithmic Synthesis X* X*
and Audio FX
17 ER AAC LC   X X X
18 (reserved)
19 ER AAC LTP   X X
20 ER AAC Scalable   X X X
21 ER TwinVQ    X X
22 ER BSAC    X X
23 ER AAC LD   X X X  X  X
24 ER CELP   X X X
25 ER HVXC   X X
26 ER HILN    X
27 ER Parametric    X
28 SSC
29 PS      X
30 MPEG Surround
31 (escape)
32 Layer-1
33 Layer-2
34 Layer-3
35 DST
36 ALS       X
37 SLS       X
38 SLS non-core
39 ER AAC ELD        X
40 SMR Simple
41 SMR Main
42 USAC
43 SAOC
44 LD MPEG Surround        X
45 SAOC-DE
46 Audio Sync
47 AAC IIF        X
*) Subset of Main Synthetic
At the end of 1.5.2.3, add the following:
— Levels for the Immersive Interchange Profile

The levels for the Immersive Interchange Profile are specified in Table 1.17.
16 © ISO ###w /IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)
Table 1.17 — Levels for the Immersive Interchange Profile
Leve Max. Max. Max. Max. Max. Max. Max. Max. Max.
l NCC audio_b out_sa audio_b numbe frame_l IIF buffer metada
us_widt mpling_ us_widt r of ength_i Block for ta
a
h rate_m h predefi dx Stream metada instanc
ultiplie ned s ta es
multipli
b
r audio (accum
ed by (numbe
present ulated)
out_sa r of
ations [KiB]
mpling_ differe
(num_a
rate_m nt
udio_pr
ultiplie metada
b esentat
r ta_insta
ions)
nce_tag
values)
1 6 8 1 2 1 15 4 8 1
2 24 32 2 16 32 31 32 64 24
3 48 64 2 32 64 31 32 128 64
4 48 128 2 48 128 31 32 256 128
5 48 256 4 64 256 31 32 512 256
6 768 256 4 256 256 31 32 8,192 256
7 3072 256 4 1024 256 31 32 8,192 256
a    These restrictions apply if lossless coding is disabled, i.e. if none of the elements in the vector
b_block_priority0_is_lossless is equal to 1 in an iif_specific_config().
b    These restrictions apply if lossless coding is enabled, i.e. if any of the elements in the vector
b_block_priority0_is_lossless is equal to 1 in an iif_specific_config().

All levels shall support Media Authenticity as defined in 4.5.2.17, including the Media Authenticity
Interface according to 4.5.2.17.3.

Update numbering of Table 1.17 to 1.18 and add the following rows after the row starting with
“0x5E”:
0x5F ALS Simple Profile L5
0x60 ALS Simple Profile L6
0x61 ALS Simple Profile L7
0x62 AAC IIF Profile L1
0x63 AAC IIF Profile L2
0x64 AAC IIF Profile L3
0x65 AAC IIF Profile L4
0x66 AAC IIF Profile L5
© ISO/IEC 2026 – All rights reserved
ISO #####-#:####(X/IEC 14496-3:2019/FDAmd 1(en)
0x67 AAC IIF Profile L6
0x68 AAC IIF Profile L7
0x69 - reserved for ISO/IEC 14496-3 -
0x6F
0x70 - reserved for ISO/IEC 23003-3 -
0x7F
Update numbering of Table 1.19 to Table 1.20, after “break;” for “case 46:” add the following:
case 47:
iif_specific_config(samplingFrequencyIndex);
break;
case 64: … case 95:
UsacAotSpecificConfig(audioObjectType);
break;
After 1.6.2.1.22, add the following:
1.6.2.1.23  iif_specific_config
Defined in subpart 4.
1.6.2.1.24  UsacAotSpecificConfig
Defined in ISO/IEC 23003-3.
Update numbering of Table 1.21 to 1.22 and add the following at the end of Table:
47 AAC IIF ISO/IEC 14496--3 Subpart 4 see
subclause 1.6.2.2.2.6
After 1.6.2.2.2.5, add the following:
1.6.2.2.2.6  AAC IIF
One top level payload (iif_access_unit()) is mapped into one access unit. A sequence of access units
forms one elementary stream.
18 © ISO ###w /IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)

Update numbering of Table 1.22 and following tables accordingly.

In Annex 1.C, replace “ISO/IEC14496-5 :2001, Information technology — Coding of audio-visual
objects — Part 5: Reference software” with:
ISO/IEC 14496-35, Information technology — Coding of audio-visual objects — Part 35: Audio
reference software
In 4.4.2.7, Table 4.59 “Syntax of extension_payload()”, after “return uniDrc();”, add the following:
case EXT_AUTH_DATA:
fill_nibble; /* 4 uimsbf
shall be ‘0000’ */
return
auth_extension();
case EXT_ADD_TYPES:
4 uimsbf
extension_type_add;
extension_type = 0xF + extension_type_add;
switch(
extension_type ) {
default:
for (i=0; i<8*(cnt-1); i++) {
1 uimsbf
other_bits[i];
}               }

return cnt;
}         }
For the base document ISO/IEC 14496-3:2019, before application of the present amendment, in
sequential order,
Increment numbering of Table 4.166 to 4.201 by 48 (resulting in numbers ranging from 4.214 to
4.249).
© ISO/IEC 2026 – All rights reserved
ISO #####-#:####(X/IEC 14496-3:2019/FDAmd 1(en)
Increment numbering of Table 4.144 to 4.165 by 36 (resulting in numbers ranging from 4.180 to
4.201).
Increment numbering of TableRenumber Tables 4.87 to 4.143 by 21 (resulting in numbers ranging
fromas Tables 4.108 to 4.164).
Renumber Tables 4.144 to 4.165 as Tables 4.180 to 4.201.
Renumber Tables 4.166 to 4.201 as Tables 4.214 to 4.249.

Add the following after 4.4.2.9:
4.4.2.10  Payloads for the audio object type AAC IIF

The following table shows an overview of syntax elements for payloads for the audio object type
AAC IIF.
Syntax Element Description
iif_access_unit() Table 4.87Table 4.87
iif_block() Table 4.88Table 4.88
iif_block_header() Table 4.89Table 4.89
iif_block_payload() Table 4.90Table 4.90
iif_audio_payload() Table 4.91Table 4.91
iif_metadata_payload() Table 4.92Table 4.92
metadata_section() Table 4.93Table 4.93
md_size(is_bytes) Table 4.94Table 4.94
iif_metadata_frame() Table 4.95Table 4.95
iif_config_update() Table 4.96Table 4.96
iif_block_footer() Table 4.97Table 4.97
wtdav_data() Table 4.98Table 4.98
lsb_plane_data() Clause 4.6.21.8.7.2Clause 4.6.21.8.7.2
single_channel_element_iif() Table 4.99Table 4.99
pred_data() Table 4.100Table 4.100
channel_pair_element_iif() Table 4.101Table 4.101
individual_channel_stream_iif() Table 4.102Table 4.102
hgr_section_data() Table 4.103Table 4.103
gr_data() Table 4.104Table 4.104
icp_data() Table 4.105Table 4.105
lms_data() Table 4.106Table 4.106
20 © ISO ###w /IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)
Syntax Element Description
zlsb_data() Table 4.107Table 4.107
Table 4.87 — Syntax of iif_access_unit()
Syntax No. of bits Mnemoni
c
iif_access_unit()
{
while (bits_to_decode() > 23) {
iif_block();
}
}
Table 4.88 — Syntax of iif_block()
Syntax No. of Mnemoni
bits c
iif_block()
{
iif_block_header();
iif_block_payload();
iif_block_footer();
}
Table 4.89 — Syntax of iif_block_header()
Syntax No. of bits Mnemon
ic
iif_block_header()
{
frame_counter; 4 uimsbf
block_id; 5 uimsbf
block_priority; 2 uimsbf
block_size; 11 uimsbf
b_block_protected; 1 uimsbf
reserved; 1 uimsbf
block_bytes_left = block_size;
if (block_size == 0x7ff) {
ext_block_size = 0;
ext_blk_size_loop_cnt = 0;
b_more_bits = 1;
© ISO/IEC 2026 – All rights reserved
ISO #####-#:####(X/IEC 14496-3:2019/FDAmd 1(en)
Syntax No. of bits Mnemon
ic
while (0 != b_more_bits) {
if (ext_blk_size_loop_cnt < 2) {
block_size_extension; 7 uimsbf
b_more_bits; 1 uimsbf
ext_block_size <<= 7;
} else {
block_size_extension; 8 uimsbf
b_more_bits = 0;
ext_block_size <<= 8;
}
ext_block_size += block_size_extension;
ext_blk_size_loop_cnt += 1;
}
block_size += ext_block_size + ext_blk_size_loop_cnt;
block_bytes_left = block_size – ext_blk_size_loop_cnt;
}
if (b_block_protected) {
block_bytes_left = block_bytes_left – 2;
}
}
frame_counter; 4 uimsbf
block_id; 5 uimsbf
block_priority; 2 uimsbf
block_size; 11 uimsbf
b_block_protected; 1 uimsbf
reserved; 1 uimsbf
block_bytes_left = block_size;

if (block_size == 0x7ff) {
ext_block_size = 0;
ext_blk_size_loop_cnt = 0;
b_more_bits = 1;
while (0 != b_more_bits) {
if (ext_blk_size_loop_cnt
< 2) {
7 uimsbf
block_size_extension;
1 uimsbf
b_more_bits;
ext_block_size <<= 7;
22 © ISO ###w /IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)

} else {
8 uimsbf
block_size_extension;
b_more_bits = 0;
ext_block_size <<= 8;
}
ext_block_size +=
block_size_extension;
ext_blk_size_loop_cnt +=
1;
}
block_size += ext_block_size +
ext_blk_size_loop_cnt;
block_bytes_left = block_size –
ext_blk_size_loop_cnt;
}
if (b_block_protected) {
block_bytes_left = block_bytes_left – 2;

}
}
Table 4.90 — Syntax of iif_block_payload()
No. of Mnemon
Syntax
bits ic
iif_block_payload()
{
/* Config Update */
b_use_default_config; 1 uimsbf
if (!b_use_default_config) {
b_config_update_inband; 1 uimsbf
if (b_config_update_inband) {
iif_config_update(0);
} else {
dynamic_config_upd_idx_minus1; 3 uimsbf
}
}
iif_metadata_payload();
/* Audio Data */
if (audio_signals_in_source_block[block_id] > 0) {
© ISO/IEC 2026 – All rights reserved
ISO #####-#:####(X/IEC 14496-3:2019/FDAmd 1(en)
No. of Mnemon
Syntax
bits ic
samplingFrequency = block_sampling_rate[block_id];
iif_audio_payload();
}
byte_alignment();
}
/* Config Update */
b_use_default_config; 1 uimsbf
if (!b_use_default_config) {
b_config_update_inband; 1 uimsbf
if (b_config_update_inband) {
iif_config_update(0);
} else {
3 uimsbf
dynamic_config_upd_idx_minus1;
}
}
iif_metadata_payload();
/* Audio Data */
if (audio_signals_in_source_block[block_id] > 0) {
samplingFrequency =
block_sampling_rate[block_id];
iif_audio_payload();
}
byte_alignment();
}
Table 4.91 — Syntax of iif_audio_payload()
No.
Mnemoni
Syntax of
c
bits
iif_audio_payload()
{
iif_lossless_enabled =
((block_priority == 0 && b_block_priority0_is_lossless[block_id] == 1) ||

(block_priority == 1 && b_block_priority1_is_lossless[block_id] == 1));

24 © ISO ###w /IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)
No.
Mnemoni
Syntax of
c
bits
b_iif_lossless_mode = b_channel_permute =

b_permute_cpe_channels = 0;
b_lsb_data = gr_par_offset = 0;

if (iif_lossless_enabled) {
b_iif_lossless_mode; 1 uimsbf
if (b_iif_lossless_mode) {
if
(audio_signals_in_source_block[block_id] > 1) {

1 uimsbf
b_channel_permute;
if
(b_channel_permute == 1) {
1 uimsbf
b_permute_cpe_channels;
ch_bits =
ceil(log2(audio_signals_in_source_block[block_id]));
}            }
}         }
b_lsb_data; 1 uimsbf
gr_par_offset; 3 uimsbf
}
}
n_channels = 0;
while (n_channels < audio_signals_in_source_block[block_id])
{
b_element_is_cpe; 1 uimsbf
if (b_element_is_cpe == 0) {
single_channel_element_iif(
n_channels,
b_iif_lossless_mode,
© ISO/IEC 2026 – All rights reserved
ISO #####-#:####(X/IEC 14496-3:2019/FDAmd 1(en)
No.
Mnemoni
Syntax of
c
bits
b_channel_permute,
b_lsb_data);
n_channels += 1;
} else {
channel_pair_element_iif(
n_channels,
b_iif_lossless_mode,
b_channel_permute + b_permute_cpe_channels,

b_lsb_data);
n_channels += 2;
}
}
}
Table 4.92 — Syntax of iif_metadata_payload()
No. of Mnemon
Syntax
bits ic
iif_metadata_payload(num_block_bits_left)
{
num_bits_left = num_block_bits_left;
num_metadata_sections = 0;
metadata_section_entry[num_metadata_sections] = -1;

if (use_explicit_metadata_signalling[block_id]) {
b_more_md_sections; 1 uimsbf
while (b_more_md_sections) {
md_type_idx; 4 uimsbf
26 © ISO ###w /IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)
No. of Mnemon
Syntax
bits ic
metadata_section_entry[num_metadata_sections] =

md_entry[block_id][md_type_idx];

num_metadata_sections += 1;
metadata_section_entry[num_metadata_sections] = -1;

1 uimsbf
b_more_md_sections;
}
} else {
for (m=0;
m
1 uimsbf
b_metadata_present;
if
(b_metadata_present) {
metadata_section_entry[num_metadata_sections] =

md_entry[block_id][m];
num_metadata_sections += 1;
metadata_section_entry[num_metadata_sections] = -1;
}         }
}
}
if (num_metadata_sections > 0) {
for (s=0; s
s++) {
num_bits_read =
metadata_section();
num_bits_left -=
num_bits_read;
}
}
}
© ISO/IEC 2026 – All rights reserved
ISO #####-#:####(X/IEC 14496-3:2019/FDAmd 1(en)
Table 4.93 — Syntax of metadata_section()
No. of Mnemoni
Syntax
bits c
metadata_section(b_metadata_framing, b_metadata_is_byte_aligned)
{
if (b_metadata_framing) {
max_chun
uimsbf
num_metadata_chunks_in_section_minus1; ks_bits
for (i = 0; i <
num_metadata_chunks_in_section_minus1 + 1; ++i) {
max_spre
chunk_number; ading_bit uimsbf
s
if
(chunk_number == 0) {
12 uimsbf
sample_offset_from_audio;
max_spre
ading_bit uimsbf
num_chunks_in_metadata_frame_minus1;
s
1 uimsbf
b_audio_time_code_exists;
if (b_audio_time_code_exists) {

64 uimsbf
audio_timestamp_nanosecs;
}
}
1 uimsbf
b_original_audio_time_code_exists;

if (b_original_audio_time_code_exists) {

64 uimsbf
original_audio_timestamp_nanosecs;
}
}
}         }
chunk_len_bytes
= md_size(true) >> 3;
for (i = 0; i <
chunk_len_bytes; ++i) {
8 uimsbf
chunk_byte;
28 © ISO ###w /IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)
No. of Mnemoni
Syntax
bits c
chunk_buffer[md_entry].push_back(chunk_byte);
}         }
if
(chunk_number == num_chunks_in_metadata_frame_minus1) {

iif_metadata_frame(metadata_type, chunk_buffer.size());
}         }
}
} else {
n_metadata_bits =
md_size(b_metadata_is_byte_aligned);
iif_metadata_frame(metadata_type,

n_metadata_bits);
}
return n_metadata_bits;
}
Note 1: chunk_buffer.push_back() inserts one byte at the end of the buffer
Note 2: chunk_buffer.size() returns the size of the buffer in bytes

Table 4.94 — Syntax of md_size()
No. of Mnemoni
Syntax
bits c
md_size(is_bytes)
{
md_size_num_bits_base = 10;
md_size_num_bits_ext = 18;
if (is_bytes) {
md_size_num_bits_base = 7;
md_size_num_bits_ext = 15;
}
md_size_n
md_size_value; um_bits_b uimsbf
ase
© ISO/IEC 2026 – All rights reserved
ISO #####-#:####(X/IEC 14496-3:2019/FDAmd 1(en)
No. of Mnemoni
Syntax
bits c
if (md_size_value == 0) {
md_size_n
ext_md_size_value; um_bits_e uimsbf
xt
md_size_value = (1 <<
md_size_num_bits_base) + ext_md_size_value;
}
if (is_bytes) {
md_size_value = md_size_value * 8;
}
return md_size_value;
}
Table 4.95 — Syntax of iif_metadata_frame()
No. of Mnemoni
Syntax
bits c
iif_metadata_frame(_md_type, _nbits)
{
switch (_md_type) {
case METADATA_TYPE_AUTH:
auth_extension();
break;
default:
_nbits uimsbf
unknown_metadata;
break;
}
}
Table 4.96 — Syntax of iif_config_update()
No. of Mnemoni
Syntax
bits c
iif_config_update(_cfg)
{
for (p = 0; p < num_audio_presentations; p++) {
if (audio_presentation_type[p] ==

AUDIO_PRESENTATION_TYPE_CHANNELS) {
30 © ISO ###w /IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)
No. of Mnemoni
Syntax
bits c
1 uimsbf
b_active_channel_config_is_super;
if
(b_active_channel_config_is_super) {

active_channel_config_idx[_cfg][p] = 0;
} else {
3 uimsbf
active_channel_config_idx_minus1;

active_channel_config_idx[_cfg][p] =

active_channel_config_idx_minus1 + 1;
}         }
active_channel_mode[_cfg][p] =

channel_config_set_channel_mode

[active_channel_config_idx[_cfg][p]];

active_channel_mask[_cfg][p] =

channel_config_set_channel_mask

[active_channel_config_idx[_cfg][p]];

if (_cfg == 0) {
1 uimsbf
b_active_channel_config_change[_cfg][p];

if (b_active_channel_config_change[_cfg][p]) {

10 uimsbf
next_channel_config_sample_offset_minus1;

next_channel_config_sample_offset[_cfg][p] =

next_channel_config_sample_offset_minus1 + 1;

© ISO/IEC 2026 – All rights reserved
ISO #####-#:####(X/IEC 14496-3:2019/FDAmd 1(en)
No. of Mnemoni
Syntax
bits c
1 uimsbf
b_next_channel_config_is_super;

if (b_next_channel_config_is_super) {

next_channel_config_idx[_cfg][p] = 0;

} else {
3 uimsbf
next_channel_config_idx_minus1;

next_channel_config_idx[_cfg][p] =

next_channel_config_idx_minus1 + 1;

}               }

next_channel_mode[_cfg][p] =
channel_config_set_channel_mode

[next_channel_config_idx[_cfg][p]];

next_channel_mask[_cfg][p] =
channel_config_set_channel_mask

[next_channel_config_idx[_cfg][p]];
}
}
}         }
}
}
if (num_target_devices > 0) {
/* init with defaults */
32 © ISO ###w /IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)
No. of Mnemoni
Syntax
bits c
for (d=0; d
{
for (s=0;
s
audio_signal_role[_cfg][d][s] = default_audio_signal_role[d][s];

audio_signal_gain[_cfg][d][s] = default_audio_signal_gain[d][s];

audio_signal_delay[_cfg][d][s] =

default_audio_signal_delay[d][s];
}         }
}
/* override */
b_override_defaults; 1 uimsbf
if (b_override_defaults == 1) {
for (d=0;
d if (_cfg >0 || device_address_mask[block_id]&(1<
/* only if parent block is addressed to this
device! */
1 uimsbf
b_override_default_role_for_device;

if (b_override_default_role_for_device) {

for (s=0;
s
1 uimsbf
b_signal_connected;
if
(b_signal_connected == 1) {
3          uimsbf
audio_signal_role[_cfg][d][s];

} else
{
© ISO/IEC 2026 – All rights reserved
ISO #####-#:####(X/IEC 14496-3:2019/FDAmd 1(en)
No. of Mnemoni
Syntax
bits c
audio_signal_role[_cfg][d][s] = -1;

}                     }

}                  }

}               }

1 uimsbf
b_override_default_params_for_device;

if (b_override_default_params_for_device) {

for (s=0;
s
if
(audio_signal_role[_cfg][d][s] >= 0) {

1          uimsbf
b_override_default_gain;
if (b_override_default_gain) {

1 uimsbf
b_reset_gain;
if (b_reset_gain) {
audio_signal_gain[_cfg][d][s] = 0;

} else {                           } else {

5 uimsbf
gain_code;
}                           }
34 © ISO ###w /IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)
No. of Mnemoni
Syntax
bits c
}
}
1          uimsbf
b_override_default_delay;
if (b_override_default_delay) {

1 uimsbf
b_relative_delay;
if (b_relative_delay == 1) {
7 uimsbf
rel_delay_code;
} else {                           } else {

12 uimsbf
delay_code;
audio_signal_delay[_cfg][d][s] =

4*delay_code;
}                           }

}
}
}                     }

}                  }

}               }
© ISO/IEC 2026 – All rights reserved
ISO #####-#:####(X/IEC 14496-3:2019/FDAmd 1(en)
No. of Mnemoni
Syntax
bits c
}
}
}         }
}
}
if (_cfg == 0) {
if (b_enable_block_tags) {
1 uimsbf
b_block_tags_update;
if
(b_block_tags_update) {
iif_block_tags_info(block_id);

iif_block_zones_info(block_id);
}         }
}
}
}
Table 4.97 — Syntax of iif_block_footer()
No. of Mnemoni
Syntax
bits c
iif_block_footer()
{
block_byt
block_fill;
es_left * 8
if (b_block_protected) {
block_crc; 16 uimsbf
}
}
Table 4.98 — Syntax of wtdav_data()
No. of Mnemoni
Syntax
bits c
wtdav_data()
{
numBits1 = pcmWordLength + 1;
numBits2 = pcmWordLength;
36 © ISO ###w /IEC 2026 – All rights reserved
ISO/IEC 14496-3:2019/DAMFDAmd 1:2026(en)
No. of Mnemoni
Syntax
...