ISO/IEC 23094-2:2021/Amd 1:2024

International
Standard
ISO/IEC 23094-2
First edition
Information technology – General
2021-11
video coding —
AMENDMENT 1
Part 2:
2024-01
Low complexity enhancement video
coding
AMENDMENT 1: Additional levels
Technologies de l'information – Codage vidéo général —
Partie 2: Codage vidéo d'amélioration de faible complexité
AMENDEMENT 1: Niveaux supplémentaires
Reference number
ISO/IEC 23094-2:2021/Amd. 1:2024(en) © ISO/IEC 2024

ISO/IEC 23094-2:2021/Amd. 1:2024(en)
© ISO/IEC 2024
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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO/IEC 2024 – All rights reserved
ii
ISO/IEC 23094-2:2021/Amd. 1:2024(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 23094 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 2024 – All rights reserved
iii
ISO/IEC 23094-2:2021/Amd. 1:2024(en)
Information technology – General video coding —
Part 2:
Low complexity enhancement video coding
AMENDMENT 1: Additional levels

Normative references
Replace "ITU-T H.273 | ISO/IEC 23091-2:2019" with "ITU-T H.273 | ISO/IEC 23091-2".

6.2
Replace:
The variables ShiftWidthC and ShiftHeightC are specified in Table 2, depending on the chroma format
sampling structure, which is specified through chroma_format_idc and separate_colour_plane_flag. Other
values of chroma_format_idc, ShiftWidthC and ShiftHeightC may be specified in the future by ISO/IEC.
with:
The variables ShiftWidthC and ShiftHeightC are specified in Table 2, depending on the chroma format
sampling structure, which is specified through chroma_sampling_type.

7.3.9
Replace Table 13 with the following table:
Table 13 — Process payload – surface
Syntax Descriptor
process_surface(surface) {
if (surface.entropy_enabled_flag) {
if (compression_type_size_per_tile == 0) {
surface.size mb
}
if (surface.rle_only_flag) {
surface.data_rle surface.size
} else {
surface.data_prefix_coding surface.size
}
}
}
© ISO/IEC 2024 – All rights reserved
ISO/IEC 23094-2:2021/Amd. 1:2024(en)
7.3.12
Replace Table 16 with the following table:
Table 16 — Byte alignment syntax
Syntax Descriptor
byte_alignment( ) {
while(!byte_aligned( ))
alignment_bit_equal_to_zero /* equal to 0 */ f(1)
}
7.4.2.2
In Table 19, replace "per picture (if no_enhancement_bit_flag == 0)" with:
per picture (if no_enhancement_bit_flag == 0 or temporal_signalling_present == 1)
Add the following sentence below Table 19:
If a NAL unit as specified in Sec. 7.3.2 contains more than one payload of the same payload_type (where
payload_type is equal to 0, 1, or 2), the values given by the last payload of such payload_type within the NAL
unit shall be used.
7.4.3.3
Replace
In order to prevent incomplete TUs, as defined in 6.3.2, custom_tile_width shall be an integer multiple of the
TU size (nTbS = 2 if transform_type is equal to 0 and nTbS = 4 if transform_type is equal to 1) for each sub-
layer and for each plane within a sub-layer.
with
In order to prevent incomplete entropy encoded quantized transform coefficient tiles, as defined in 9.1.1,
custom_tile_width shall be an integer multiple of 64 for each sub-layer and for each plane within a sub-layer.
Replace
In order to prevent incomplete Tus, as defined in 6.3.2, custom_tile_height shall be an integer multiple of the
TU size (nTbS = 2 if transform_type is equal to 0 and nTbS = 4 if transform_type is equal to 1) for each sub-
layer and for each plane within a sub-layer.
with
In order to prevent incomplete entropy encoded quantized transform coefficient tiles, as defined in 9.1.1,
custom_tile_height shall be an integer multiple of 64 for each sub-layer and for each plane.
Replace
planes_type specifies the planes to be processed by the decoder according to Table 25.
with
planes_type specifies the planes to be processed by the decoder according to Table 25. If chroma_sampling_
type is equal to 0, planes_type shall be equal to 0.

© ISO/IEC 2024 – All rights reserved
ISO/IEC 23094-2:2021/Amd. 1:2024(en)
7.4.3.4
Replace:
temporal_signalling_present_flag specifies whether the temporal signalling coefficient group is present
in the bitstream.
with:
temporal_signalling_present_flag specifies whether the temporal signalling coefficient group is present
in the bitstream. If temporal_enabled_flag is equal to 0 or temporal_refresh_bit_flag is equal to 1, temporal_
signalling_present_flag shall be equal to 0.

8.3.2
Delete the following:
— variable nPlanes is derived as follows:
if (processed_planes_type_flag == 0)
nPlanes = 1
else
nPlanes = 3
Delete "data = read_byte(bitstream)” from the condition branch below
if (surfaces[planeIdx][levelIdx][layerIdx].rle_only_flag) {
multibyte = read_multibyte(bitstream)
surfaces[planeIdx][levelIdx][layerIdx].size = multibyte
surfaces[planeIdx][levelIdx][layerIdx].data_rle =
bytestream_current(bitstream)
} else {
data = read_byte(bitstream)
multibyte = read_multibyte(bitstream)
surfaces[planeIdx][levelIdx][layerIdx].size = multibyte
surfaces[planeIdx][levelIdx][layerIdx].data_prefix_coding =
bytestream_current(bitstream)
bytestream_seek(bitstream, surfaces[planeIdx][levelIdx][layerIdx].size)
}
Delete "data = read_byte(bitstream)” from the condition branch below
if (temporal_signalling_present_flag == 1) {
if (temporal_surfaces[planeIdx].entropy_enabled_flag) {
if (temporal_surfaces[planeIdx].rle_only_flag) {
multibyte = read_multibyte(bitstream)
temporal_surfaces[planeIdx].size = multibyte
temporal_surfaces[planeIdx].data_rle = bytestream_current(bitstream)
} else {
data = read_byte(bitstream)
multiby
...