ISO/IEC 23090-5:2023

Information technology - Coded representation of immersive media - Part 5: Visual volumetric video-based coding (V3C) and video-based point cloud compression (V-PCC)

This document specifies the syntax, semantics and decoding for visual volumetric media using video‑based coding methods. This document also specifies processes that can be needed for reconstruction of visual volumetric media, which can also include additional processes such as post‑decoding, pre-reconstruction, post‑reconstruction and adaptation.

Technologie de l'information — Représentation codée de média immersifs — Partie 5: Codage basé sur la vidéo volumétrique (V3C) et compression de nuage de points basée sur la vidéo (V-PCC)

General Information

• Status: Published
• Publication Date: 09-Nov-2023
• 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 7 - MPEG 3D Graphics coding
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 03-Mar-2025
• Completion Date: 30-Oct-2025

Relations

• Revised: ISO/IEC 23090-5:2025 - Information technology - Coded representation of immersive media - Part 5: Visual volumetric video-based coding (V3C) and video-based point cloud compression (V-PCC)
• Effective Date: 17-Feb-2024
• Revises: ISO/IEC 23090-5:2021 - Information technology -- Coded representation of immersive media
• Effective Date: 21-Aug-2021

Overview

ISO/IEC 23090-5:2023 defines the coded representation and decoding model for visual volumetric media using video‑based methods. Commonly referenced as V3C (Visual Volumetric Video‑based Coding) and covering V‑PCC (Video‑based Point Cloud Compression), the standard specifies the syntax, semantics and decoding processes for bitstreams that represent volumetric/point‑cloud scenes. It also details auxiliary processes that support reconstruction - including post‑decoding, pre‑reconstruction, post‑reconstruction and adaptation - enabling interoperable delivery and rendering of immersive media.

Key topics and technical requirements

• Bitstream structure and formats: Definitions for V3C unit and NAL (Network Abstraction Layer) bitstream formats, partitioning of atlas frames into tiles, and sample stream layouts.
• Syntax and semantics: Tabular specification of syntax elements, descriptors, and semantics for V3C parameter sets, atlas tile data units, SEI (Supplemental Enhancement Information) messages, and raw byte payloads.
• Decoding pipeline: Detailed decoding processes for atlas data, occupancy, geometry, attribute, and packed videos; sub‑bitstream extraction; and parsing (including Exp‑Golomb coding handling).
• Reconstruction & post‑processing: Processes required to convert decoded video streams into volumetric geometry/attributes, including optional conversion to nominal video formats and adaptation for varying client capabilities.
• Profiles, tiers and levels: Conformance points that define interoperability ranges (see normative annexes).
• V‑PCC integration: Normative Annex H specifies the video‑based point cloud compression workflow and requirements for representing point clouds using video coding primitives.
• Reference materials: Annexes include sample stream formats, a hypothetical reference decoder, and volumetric usability information for implementers.

Practical applications

• Streaming and delivery of volumetric video for VR/AR/immersive experiences
• Real‑time telepresence and free‑viewpoint video applications
• Efficient transmission and storage of 3D point clouds for mapping, digital twins, and cultural heritage capture
• Authoring and playback toolchains that reconstruct geometry and texture from compressed atlases
• Networked experiences that require adaptation of volumetric content to device capabilities and bandwidth

Who should use this standard

• Codec and middleware implementers building V3C / V‑PCC encoders and decoders
• Immersive media platform and streaming providers
• VR/AR application developers and graphics engine integrators
• Hardware vendors (SoC, GPU) implementing decoding acceleration
• Researchers and standards professionals working on 3D media interoperability

Related standards

• Other parts of the ISO/IEC 23090 series (Coded representation of immersive media)
• References and additions for ISO/IEC 23090‑12 (MPEG Immersive Video) are reflected in this edition

Keywords: ISO/IEC 23090-5:2023, V3C, V‑PCC, visual volumetric video, video‑based point cloud compression, immersive media, volumetric video, atlas, NAL, decoding, reconstruction, point cloud compression.

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 23090-5
Second edition
2023-11
Information technology — Coded
representation of immersive media —
Part 5:
Visual volumetric video-based coding
(V3C) and video-based point cloud
compression (V-PCC)
Technologie de l'information — Représentation codée de média
immersifs —
Partie 5: Codage basé sur la vidéo volumétrique (V3C) et compression
de nuage de points basée sur la vidéo (V-PCC)
Reference number
© ISO/IEC 2023
© ISO/IEC 2023
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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
© ISO/IEC 2023 – All rights reserved

Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms .15
5 Conventions .16
5.1 General . 16
5.2 Arithmetic operators . 17
5.3 Logical operators . 17
5.4 Relational operators . 17
5.5 Bit-wise operators . 17
5.6 Assignment operators . 18
5.7 Other operators . 18
5.8 Mathematical functions . 18
5.9 Order of operation precedence . 19
5.10 Variables, syntax elements, and tables . 20
5.11 Text description of logical operations . 21
5.12 Processes . 23
6 Overall V3C characteristics, decoding operations, and post-decoding processes .23
6.1 V3C characteristics .23
6.2 V3C bitstream characteristics, decoding operations, and post-decoding processes .26
7 Bitstream format, partitioning, and scanning processes .27
7.1 General . 27
7.2 V3C bitstream formats . 27
7.3 NAL bitstream formats .28
7.4 Partitioning of atlas frames into tiles .28
7.5 Tile partition scanning process .29
8 Syntax and semantics .30
8.1 Method of specifying syntax in tabular form . .30
8.2 Specification of syntax functions and descriptors . 31
8.3 Syntax in tabular form . 33
8.3.1 General . 33
8.3.2 V3C unit syntax . 35
8.3.3 Byte alignment syntax .36
8.3.4 V3C parameter set syntax . 36
8.3.5 NAL unit syntax . . 42
8.3.6 Raw byte sequence payloads, trailing bits, and byte alignment syntax . 43
8.3.7 Atlas tile data unit syntax .50
8.3.8 Supplemental enhancement information message syntax .54
8.4 Semantics . 55
8.4.1 General . 55
8.4.2 V3C unit semantics .55
8.4.3 Byte alignment semantics . 57
8.4.4 V3C parameter set semantics . 57
8.4.5 NAL unit semantics . 67
8.4.6 Raw byte sequence payloads, trailing bits, and byte alignment semantics .77
8.4.7 Atlas tile data unit semantics . 91
8.4.8 Supplemental enhancement information message semantics .99
9 Decoding process .99
9.1 General decoding process .99
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© ISO/IEC 2023 – All rights reserved

9.2 Atlas data decoding process .101
9.2.1 General atlas data decoding process . 101
9.2.2 Decoding process for a coded atlas frame . 101
9.2.3 Atlas NAL unit decoding process .102
9.2.4 Atlas tile header decoding process .103
9.2.5 Decoding process for patch data units .107
9.2.6 Decoding process of the block to patch map .122
9.2.7 Conversion of tile level patch information to atlas level patch information .123
9.3 Occupancy video decoding process .125
9.4 Geometry video decoding process .126
9.5 Attribute video decoding process .129
9.6 Packed video decoding process .131
9.7 Common atlas data decoding process.132
9.7.1 General common atlas data decoding process.132
9.7.2 Decoding process for a coded common atlas frame .133
9.7.3 Common atlas NAL unit decoding process . .133
9.7.4 Common atlas frame order count derivation process . .133
9.8 Sub-bitstream extraction process .135
9.8.1 General .135
9.8.2 V3C unit extraction .135
9.8.3 NAL unit extraction process .136
10 Pre-reconstruction process . 136
11 Reconstruction process . 136
12 Post-reconstruction process . 137
13 Adaptation process . 137
14 Parsing process . 137
14.1 General .137
14.2 Parsing process for 0-th order Exp-Golomb codes.137
14.2.1 General .137
14.2.2 Mapping process for signed Exp-Golomb codes .138
Annex A (normative) Profiles, tiers, and levels . 140
Annex B (informative) Post-decoding conversion to nominal video formats . 152
Annex C (informative) V3C sample stream format.179
Annex D (normative) NAL sample stream format . 181
Annex E (normative) Atlas hypothetical reference decoder . 183
Annex F (normative) Supplemental enhancement information . 200
Annex G (informative) Volumetric usability information . 257
Annex H (normative) Video-based Point Cloud Coding .268
Bibliography . 351
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© ISO/IEC 2023 – 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.
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 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.
This second edition cancels and replaces the first edition (ISO/IEC 23090-5:2021), which has been
technically revised.
The main changes are as follows:
— Additions needed for ISO/IEC 23090-12 MPEG Immersive video
— Various minor improvements and corrections.
A list of all parts in the ISO/IEC 23090 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.
v
© ISO/IEC 2023 – All rights reserved

Introduction
Advances in 3D capturing and rendering technologies have unleashed a new wave of innovation in
Virtual/Augmented/Mixed reality (VR/AR/MR) content creation and communication, of which visual
volumetric video is an integral part.
Visual volumetric video, a sequence of visual volumetric frames, if uncompressed, may be represented
by a large amount of data, which can be costly in terms of storage and transmission. This has led to the
need for a high coding efficiency standard for the compression of visual volumetric data.
Visual volumetric frames can be coded by converting the 3D volumetric information into a collection of
2D images and associated data. The converted 2D images can be coded using widely available video and
image coding specifications, such as ISO/IEC 14492-10 and ISO/IEC 23008-2 and the associated data
can be coded with mechanisms specified in this document. The coded images and the associated data
can then be decoded and used to reconstruct the 3D volumetric information. This document specifies
a generic mechanism for visual volumetric video coding, i.e. visual volumetric video-based coding. The
generic mechanism may be used by applications targeting volumetric content, such as point clouds,
immersive video with depth, mesh representations of visual volumetric frames, etc.
In addition to the generic mechanism of coding volumetric content, this document specifies one of the
applications of visual volumetric video-based coding targeting point cloud representations of visual
volumetric frames. In a point cloud sequence, each point cloud frame contains a collection of points.
Each point has a 3D position, i.e., geometry information, and each point may also be associated with a
number of attributes, such as colour, reflectance, surface normal, etc.
vi
© ISO/IEC 2023 – All rights reserved

INTERNATIONAL STANDARD ISO/IEC 23090-5:2023(E)
Information technology — Coded representation of
immersive media —
Part 5:
Visual volumetric video-based coding (V3C) and video-
based point cloud compression (V-PCC)
1 Scope
This document specifies the syntax, semantics, and decoding for visual volumetric media using
video-based coding methods. Furthermore, this document specifies processes that may be needed
for reconstruction of visual volumetric media, and may also include additional processes such as
post-decoding, pre-reconstruction, post-reconstruction, and adaptation.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitute requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 10646, Information technology — Universal coded character set (UCS)
ISO/IEC 14496-10, Information technology — Coding of audio-visual objects — Part 10: Advanced video
coding
ISO/IEC 14496-12, Information technology — Coding of audio-visual objects — Part 12: ISO base media file
format
ISO/IEC 14496-15, Information technology — Coding of audio-visual objects — Part 15: Carriage of
network abstraction layer (NAL) unit structured video in the ISO base media file format
ISO/IEC 23008-2, Information technology — High efficiency coding and media delivery in heterogeneous
environments — Part 2: High efficiency video coding
ISO/IEC 23090-3, Information technology — Coded representation of immersive media — Part 3: Versatile
video coding
ISO/IEC 23091-2, Coding-independent code points for video signal type identification
Rec. ITU-T T.35, Procedure for the allocation of ITU-T defined codes for non standard facilities
Rec. ITU-T H.271, Video back-channel messages for conveyance of status information and requests from a
video receiver to a video sender
IEEE 754-2019, IEEE Standard for Floating-Point Arithmetic
IETF RFC 1321, The MD5 Message-Digest Algorithm
IETF RFC 5646, Tags for Identifying Languages
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
© ISO/IEC 2023 – All rights reserved

ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
3D bounding box
volume defined as a cuboid solid having six rectangular faces placed at right angles
3.2
associated non-ACL NAL unit
non-ACL NAL unit (3.81) that is associated with an ACL NAL unit (3.5) for the purpose of decoding or
other operations specified by this document
3.3
atlas
collection of 2D bounding boxes and their associated information placed onto a rectangular frame and
corresponding to a volume in 3D space on which volumetric data is rendered
3.4
atlas bitstream
sequence of bits that forms the representation of atlas frames (3.7) and associated data forming one or
more CASs (3.35)
3.5
atlas coding layer NAL unit
ACL NAL unit
collective term for coded atlas tile layer NAL units (3.79) and the subset of NAL units (3.79) that have
reserved values of nal_unit_type that are classified as being of type class equal to ACL in this document
3.6
atlas coordinates
two scalars (x, y) with finite precision and dynamic range that indicate the location of an atlas sample
relative to the top left corner of an atlas frame, with x and y indicating the horizontal and vertical
direction, respectively
3.7
atlas frame
2D rectangular array of atlas samples onto which patches (3.88) are projected and additional
information related to the patches (3.88), corresponding to a volumetric frame (3.139)
3.8
atlas frame parameter set
AFPS
syntax structure (3.121) containing syntax elements (3.120) that apply to zero or more entire coded atlas
frames (3.7) as determined by the content of a syntax element (3.120) found in each tile header
3.9
atlas sample
position on the rectangular frame onto which patches (3.88) that are associated with an atlas (3.3) are
projected
3.10
atlas sequence
collection of atlas frames (3.7)
© ISO/IEC 2023 – All rights reserved

3.11
atlas sequence parameter set
ASPS
syntax structure (3.121) containing syntax elements (3.120) that apply to zero or more entire coded atlas
sequences (3.34) as determined by the content of a syntax element (3.120) found in the AFPS referred to
by a syntax element found in each tile header
3.12
atlas sub-bitstream
extracted sub-bitstream (3.109) from the V3C bitstream (3.129) containing a part of an atlas NAL
bitstream
3.13
atlas unit
set of NAL units (3.79) that contain all ACL NAL units (3.5) of a coded atlas (3.33) and their associated
non-ACL NAL units (3.2)
3.14
attribute
scalar or vector property optionally associated with each point in a volumetric frame (3.139) such as
colour, reflectance, surface normal, transparency, material ID, etc.
3.15
attribute access unit
collection of attribute maps (3.17) and auxiliary attribute frames, if available, for a specific attribute
(3.14) that correspond to the same time instance
3.16
attribute frame
2D rectangular array created through the aggregation of patches (3.88) containing values of a specific
attribute (3.14)
3.17
attribute map
attribute frame (3.16) containing attribute patch (3.88) information projected at a particular depth
indicated by the corresponding geometry map (3.64)
3.18
auxiliary attribute frame
2D rectangular array that is associated with RAW patches (3.104) and EOM patches (3.56), and contains
values of a specific attribute (3.14)
3.19
auxiliary geometry frame
2D rectangular array that is associated with RAW patches (3.104) and contains geometry (3.61) values
3.20
auxiliary video component
video component (3.126) indicated as being of auxiliary type through an appropriate flag in the VPS
(3.135) and containing data only associated with RAW patches (3.104) and/or EOM patches (3.56)
3.21
auxiliary video sub-bitstream
video sub-bitstream (3.128) indicated as being of auxiliary type through an appropriate flag in the VPS
(3.135) and containing data only associated with RAW patches (3.104) and/or EOM patches (3.56)
3.22
bitstream
ordered series of bits that forms the coded representation of the data
© ISO/IEC 2023 – All rights reserved

3.23
byte
sequence of 8 bits, within which, when written or read as a sequence of bit values, the left-most and
right-most bits represent the most and least significant bits, respectively
3.24
broken link access access unit
BLA access unit
access unit in which the coded atlas (3.33) with nal_layer_id equal to 0 is a BLA coded atlas (3.25)
3.25
broken link access coded atlas frame
BLA coded atlas
BLA atlas frame
IRAP coded atlas (3.75) frame for which each ACL NAL unit (3.5) has nal_unit_type equal to NAL_BLA_W_
LP, NAL_GBLA_W_LP, NAL_BLA_W_RADL NAL_GBLA_W_RADL, NAL_BLA_N_LP or NAL_GBLA_N_LP.
Note 1 to entry: A BLA coded atlas does not use inter prediction in its decoding process, and could be the first
coded atlas in the bitstream in decoding order, or could appear later in the bitstream. Each BLA coded atlas
begins a new CAS, and has the same effect on the decoding process as an instantaneous decoding refresh (IDR)
coded atlas. However, a BLA coded atlas contains syntax elements that specify a non-empty DAB. When a BLA
coded atlas frame for which each ACL NAL unit has nal_unit_type equal to NAL_BLA_W_LP or NAL_GBLA_W_LP,
it may have associated random access skipped leading (RASL) coded atlas frames, which are not output by the
decoder and may not be decodable, as they may contain references to atlas frames that are not present in the
bitstream. When a BLA coded atlas frame for which each ACL NAL unit has nal_unit_type equal to NAL_BLA_W_
LP or NAL_GBLA_W_LP, it may also have associated RADL coded atlas frames, which are specified to be decoded.
When a BLA coded atlas frame for which each ACL NAL unit has nal_unit_type equal to NAL_BLA_W_RADL or
NAL_GBLA_W_RADL, it does not have associated RASL coded atlas frames but may have associated random
access decodable leading (RADL) coded atlas frames. When a BLA coded atlas frame for which each ACL NAL unit
has nal_unit_type equal to NAL_BLA_N_LP or NAL_GBLA_N_LP, it does not have any associated leading coded
atlas frames.
3.26
byte-aligned
positioned as an integer multiple of 8 bits from the position of the first bit in the bitstream (3.22)
3.27
byte-aligned position
position in a bitstream (3.22) that is byte-aligned (3.26)
3.28
byte-aligned byte
byte (3.23) that appears in a position in a bitstream (3.22) that is byte-aligned (3.26)
3.29
Cartesian coordinates
three scalars (x, y, z) with finite precision and dynamic range that indicate the location of a point relative
to a fixed reference point (the origin)
3.30
clean random access access unit
CRA access unit
access unit in which the coded atlas (3.33) with nal_layer_id equal to 0 is a CRA coded atlas (3.31)
© ISO/IEC 2023 – All rights reserved

3.31
clean random access coded atlas frame
CRA coded atlas
CRA atlas frame
IRAP coded atlas (3.75) for which each ACL NAL unit (3.5) has nal_unit_type equal to NAL_CRA or NAL_
GCRA
Note 1 to entry: A CRA coded atlas does not use inter prediction in its decoding process, and could be the first
coded atlas in the bitstream in decoding order, or could appear later in the bitstream. A CRA coded atlas could
have associated RADL or RASL coded atlas frames. When a CRA coded atlas has NoOutputBeforeRecoveryFlag
equal to 1, the associated RASL coded atlas frames are not output by the decoder, because they might not be
decodable, as they could contain references to coded atlas frames that are not present in the bitstream.
3.32
codec
specification, device, or system that specifies or uses well defined instructions for encoding or decoding
a digital data, i.e. image or video, stream or signal
3.33
coded atlas
coded atlas frame
coded representation of an atlas (3.3)
3.34
coded atlas access unit
set of atlas NAL units (3.79) that are associated with each other according to a specified classification
rule, are consecutive in decoding order, and contain all atlas NAL units (3.79) pertaining to one
particular output time
3.35
coded atlas sequence
CAS
sequence of coded atlas access units (3.34), in decoding order, of an IRAP coded atlas access unit (3.74)
with NoOutputBeforeRecoveryFlag equal to 1, followed by zero or more coded atlas access units (3.34)
that are not IRAP coded atlas access units (3.74) with NoOutputBeforeRecoveryFlag equal to 1, including
all subsequent access units (3.34) up to but not including any subsequent coded atlas access unit (3.34)
that is an IRAP coded atlas access unit (3.74) with NoOutputBeforeRecoveryFlag equal to 1.
Note 1 to entry: An IRAP coded atlas access unit may be an IDR coded atlas access unit, a BLA coded atlas access
unit, or a CRA coded atlas access unit. The value of NoOutputBeforeRecoveryFlag is equal to 1 for each IDR coded
atlas access unit, each BLA coded atlas access unit, and each CRA coded atlas access unit that is the first coded
atlas access unit in the atlas bitstream in decoding order, is the first coded atlas access unit that follows an end of
sequence NAL unit in decoding order, or has HandleCraAsBlaFlag equal to 1.
3.36
coded common atlas access unit
set of common atlas non-ACL NAL units (3.81) that are associated with each other according to a
specified classification rule, are consecutive in decoding order, and contain all common atlas NAL units
(3.79) pertaining to one particular output time
3.37
coded common atlas frame
coded representation of a common atlas frame (3.44)
© ISO/IEC 2023 – All rights reserved

3.38
coded common atlas sequence
CCAS
sequence of coded common atlas access units (3.36), in decoding order, of an IRAP coded common atlas
access unit (3.77), followed by zero or more coded common atlas access units (3.36) that are not IRAP
coded common atlas access units (3.77), including all subsequent access units (3.36) up to but not
including any subsequent coded common atlas access unit (3.36) that is an IRAP coded common atlas
access unit (3.77)
3.39
coded volumetric frame
collection of coded representations of an atlas (3.3), occupancy (3.86), geometry access unit (3.62), and,
for each available attribute (3.14), attribute access unit (3.15), pertaining to one particular time instance
3.40
coded V3C sequence
CVS
sequence of V3C sub-bitstreams (3.134) identified and separated by appropriate delimiters, required to
start with a VPS (3.135), included in at least one V3C unit (3.136) or provided through external means,
and contains one or more V3C units that can be factored into V3C composition units (3.132), where the
first V3C composition unit is a V3C IRAP composition unit (3.133)
3.41
coded representation
data element as represented in its coded form
3.42
coded sub-bitstream sequence
sub-bitstream IRAP composition unit (3.111) followed by zero or more sub-bitstream composition units
(3.110)
3.43
coded V3C component
coded representation of a V3C component (3.130)
3.44
common atlas frame
CAF
common information (e.g. projection parameters) that applies to all atlas frames (3.7) in a volumetric
frame (3.139)
3.45
common atlas sequence
collection of common atlas frames (3.44)
3.46
common atlas sub-bitstream
extracted sub-bitstream (3.109) from the V3C bitstream (3.129) containing a part of a common atlas
NAL bitstream
3.47
component bitstream
bitstream (3.22) representing a V3C component (3.130)
3.48
component sub-bitstream
portion of component bitstream (3.44)
3.49
composition time
time or time period at which a frame needs to be composed, used for reconstruction, or presented
© ISO/IEC 2023 – All rights reserved

3.50
composition time index
index to an ordered list of composition times (3.49)
3.51
composition unit
partition of a bitstream (3.22) that has a certain composition time (3.49)
3.52
decoder under test
DUT
decoder that is tested for conformance to this document by operating the hypothetical stream scheduler
to deliver a conforming bitstream (3.22) to the decoder and to the hypothetical reference decoder and
comparing the values and timing or order of the output of the two decoders
3.53
decoding unit
sub-set of a coded atlas access unit (3.34) consisting of one or more ACL NAL units in a coded atlas access
unit (3.34) and the associated non-ACL NAL units (3.2)
3.54
enhanced occupancy mode
EOM
patch coding mode where a patch (3.88) is associated with enhanced occupancy information
3.55
EOM coded points
coded representation of 3D points located at intermediate depth positions for which geometry (3.61)
values are stored as codewords in the occupancy frame (3.87) and their corresponding attributes values
are stored in additional patches, referred to as EOM patches (3.56), in the attribute frames (3.16)
3.56
EOM patch
patch (3.88) with patch mode (3.90) equal to I_EOM, P_EOM, or P_SKIP
3.57
EOM patch type
patch type (3.91) indicating an EOM patch (3.56)
3.58
essential supplemental enhancement information
ESEI
SEI (3.118) that is deemed as essential by the decoding process and should not be ignored or discarded
3.59
essential supplemental enhancement information NAL unit
ESEI NAL unit
NAL unit (3.79) corresponding to an ESEI (3.58) and has nal_unit_type equal to NAL_PREFIX_ESEI or
NAL_SUFFIX_ESEI
3.60
flag
variable or single-bit syntax element that can take one of the two possible values: 0 and 1
3.61
geometry
set of Cartesian coordinates (3.29) associated with a volumetric frame (3.139)
© ISO/IEC 2023 – All rights reserved

3.62
geometry access unit
collection of geometry maps (3.64) and auxiliary geometry frames, if present, corresponding to the
same time instance
3.63
geometry frame
2D array created through the aggregation of the geometry (3.61) information associated with each
patch (3.88)
3.64
geometry map
geometry frame (3.63) containing geometry patch (3.88) information projected at a particular depth
3.65
global broken link access coded atlas frame
GBLA atlas frame
IRAP coded atlas (3.75) frame for which each ACL NAL unit (3.5) has nal_unit_type equal to NAL_
GBLA_W_LP, NAL_GBLA_W_RADL, or NAL_GBLA_N_LP respectively
3.66
global clean random access coded atlas frame
GCRA atlas frame
IRAP coded atlas (3.75) frame for which each ACL NAL unit (3.5) has nal_unit_type equal to NAL_GCRA
3.67
global instantaneous decoding refresh coded atlas frame
GIDR atlas frame
coded atlas (3.33) for which each ACL NAL unit (3.5) has nal_unit_type equal to NAL_GIDR_W_RADL,
NAL_GBLA_N_LP, or NAL_GCRA, or in the range of NAL_GBLA_W_LP to NAL_GBLA_N_LP, inclusive, and
specify a random access association between the current coded atlas and its corresponding coded video
frames at the same composition time
3.68
hypothetical reference decoder
HRD
hypothetical decoder model that specifies constraints on the variability of conforming atlas NAL unit
(3.79) streams or conforming coded atlas (3.33) sample streams that an encoding process may produce
3.69
hypothetical stream scheduler
HSS
hypothetical delivery mechanism used for checking the conformance of an atlas sub-bitstream (3.12) or
a decoder with regards to the timing and data flow of the input of an atlas sub-bitstream (3.12) into the
hypothetical reference decoder (3.68)
3.70
instantaneous decoding refresh coded atlas access unit
IDR coded atlas access unit
access unit in which the coded atlas (3.33) with nal_layer_id equal to 0 is an IDR coded atlas (3.71)
© ISO/IEC 2023 – All rights reserved

3.71
instantaneous decoding refresh coded atlas frame
IDR coded atlas
IDR atlas frame
IRAP coded atlas (3.75) for which each ACL NAL unit (3.5) has nal_unit_type equal to NAL_IDR_W_RADL,
or NAL_IDR_N_LP, NAL_GIDR_W_RADL, or NAL_GIDR_N_LP
Note 1 to entry: An IDR coded atlas does not refer to any atlases other than itself for inter prediction in its
decoding process, and may be the first atlas in the bitstream in decoding order, or may appear later in the
bitstream. Each IDR coded atlas is the first atlas of a CAS in decoding order. When an IDR coded atlas for which
each ACL NAL unit has nal_unit_type equal to NAL_IDR_W_RADL or NAL_GIDR_W_RADL, it may have associated
RADL coded atlases. When an IDR coded atlas for which each ACL NAL unit has nal_unit_type equal to NAL_
IDR_N_LP or NAL_GIDR_N_LP, it does not have any associated leading coded atlases. An IDR coded atlas does not
have associated RASL coded atlases.
3.72
inter atlas tile
atlas tile that may be decoded using both intra or inter prediction methods
3.73
intra atlas tile
atlas tile that is decoded using only intra prediction methods
3.74
intra random access point coded atlas access unit
IRAP coded atlas access unit
access unit in which the coded atlas (3.33) with nal_layer_id equal to 0 is an IRAP coded atlas (3.75)
3.75
intra random access point coded atlas frame
IRAP coded atlas
IRAP coded atlas frame
coded atlas (3.33) for which each ACL NAL unit (3.5) has nal_unit_type in the range of NAL_BLA_W_LP to
NAL_RSV_IRAP_ACL_29, inclusive
Note 1 to entry: An IRAP coded atlas does not refer to any coded atlases other than itself for prediction in its
decoding process, and may be a BLA coded atlas, a CRA coded atlas, or an IDR coded atlas. Provided the necessary
parameter sets are available when they need to be activated, the IRAP coded atlas and all subsequent non-RASL
coded atlas in decoding order can be correctly decoded without performing the decoding process of any coded
atlases that precede the IRAP coded atlas in decoding order.
3.76
intra random access point coded common atlas
IRAP coded common atlas
coded common atlas frame (3.37) for which at least one non-ACL NAL unit (3.81) has nal_unit_type equal
to NAL_CAF_IDR
3.77
intra random access point coded common atlas access unit
IRAP coded common atlas access unit
coded common access unit (3.36) in which the coded common atlas frame (3.37) has nal_layer_id equal to
0 is and and nal_unit_type equal to NAL_CAF_IDR
3.78
multi-component collection of V3C sub-bitstreams
V3C sub-bitstreams (3.134) of multiple V3C components (3.130) that, when decoded, enable the
reconstruction of volumetric content
© ISO/IEC 2023 – All rights reserved

3.79
network abstraction layer unit
NAL unit
syntax structure containing an indication of the type of data to follow and bytes (3.23) containing that
data in the form of an RBSP (3.102)
3.80
network abstraction layer unit stream
NAL unit stream
sequence of NAL units (3.79)
3.81
non-ACL NAL unit
NAL unit (3.79) that is not an ACL NAL unit (3.5)
3.82
non-auxiliary video component
regular video component
video component (3.126) indicated as being of non-auxiliary type through an appropriate flag in the VPS
(3.135)
3.83
non-auxiliary video sub-bitstream
regular video sub-bitstream
video sub-bitstream (3.128) indicated as being of non-auxiliary type through an appropriate flag in the
VPS (3.135)
3.84
non-essential supplemental enhancement information
NSEI
SEI (3.118) that is deemed as non essential by the decoding process and may be ignored or discarded
without any adverse effects
3.85
non-essential supplemental enhancement information NAL unit
NSEI NAL unit
NAL unit (3.79) corresponding to a NSEI (3.84) and has nal_unit_type equal to NAL_PREFIX_NSEI or
NAL_SUFFIX_NSEI
3.86
occupancy
values that indicate whether atlas samples (3.9) correspond to associated samples in 3D space
3.87
occupancy frame
collection of occupancy (3.86) values that constitute a 2D array and represents the entire occupancy
(3.86) information of a single atlas frame (3.7)
3.88
patch
rectangular region within an atlas (3.3) associat
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