ISO/IEC 23008-2:2020

INTERNATIONAL ISO/IEC
STANDARD 23008-2
Fourth edition
2020-08
Information technology — High
efficiency coding and media delivery
in heterogeneous environments —
Part 2:
High efficiency video coding
Technologies de l'information — Codage à haute efficacité et livraison
des medias dans des environnements hétérogènes —
Partie 2: Codage vidéo à haute efficacité
Reference number
©
ISO/IEC 2020
© ISO/IEC 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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ii © ISO/IEC 2020 – All rights reserved

Contents  Page
Foreword . vii
Introduction . viii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms .21
5 Conventions.23
5.1 General . 23
5.2 Arithmetic operators . 23
5.3 Logical operators . 23
5.4 Relational operators . 24
5.5 Bit-wise operators . 24
5.6 Assignment operators. 24
5.7 Range notation . 25
5.8 Mathematical functions . 25
5.9 Order of operation precedence . 26
5.10 Variables, syntax elements, and tables . 27
5.11 Text description of logical operations . 28
5.12 Processes . 29
6 Bitstream and picture formats, partitionings, scanning processes, and neighbouring
relationships .30
6.1 Bitstream formats. 30
6.2 Source, decoded, and output picture formats . 30
6.3 Partitioning of pictures, slices, slice segments, tiles, CTUs, and CTBs . 33
6.3.1 Partitioning of pictures into slices, slice segments, and tiles . 33
6.3.2 Block and quadtree structures . 34
6.3.3 Spatial or component-wise partitionings . 35
6.4 Availability processes . 36
6.4.1 Derivation process for z-scan order block availability. 36
6.4.2 Derivation process for prediction block availability . 37
6.5 Scanning processes . 38
6.5.1 CTB raster and tile scanning conversion process . 38
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6.5.2 Z-scan order array initialization process . 39
6.5.3 Up-right diagonal scan order array initialization process . 40
6.5.4 Horizontal scan order array initialization process . 40
6.5.5 Vertical scan order array initialization process . 41
6.5.6 Traverse scan order array initialization process . 41
7 Syntax and semantics . 41
7.1 Method of specifying syntax in tabular form . 41
7.2 Specification of syntax functions and descriptors . 43
7.3 Syntax in tabular form . 45
7.3.1 NAL unit syntax . 45
7.3.2 Raw byte sequence payloads, trailing bits, and byte alignment syntax . 45
7.3.3 Profile, tier and level syntax . 54
7.3.4 Scaling list data syntax . 57
7.3.5 Supplemental enhancement information message syntax . 58
7.3.6 Slice segment header syntax . 59
7.3.7 Short-term reference picture set syntax . 63
7.3.8 Slice segment data syntax. 64
7.4 Semantics . 80
7.4.1 General . 80
7.4.2 NAL unit semantics . 80
7.4.3 Raw byte sequence payloads, trailing bits, and byte alignment semantics . 90
7.4.4 Profile, tier, and level semantics . 113
7.4.5 Scaling list data semantics . 117
7.4.6 Supplemental enhancement information message semantics . 120
7.4.7 Slice segment header semantics . 121
7.4.8 Short-term reference picture set semantics . 130
7.4.9 Slice segment data semantics . 133
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8 Decoding process . 149
8.1 General decoding process . 149
8.1.1 General . 149
8.1.2 CVSG decoding process. 150
8.1.3 Decoding process for a coded picture with nuh_layer_id equal to 0 . 150
8.2 NAL unit decoding process . 153
8.3 Slice decoding process . 153
8.3.1 Decoding process for picture order count . 153
8.3.2 Decoding process for reference picture set . 154
8.3.3 Decoding process for generating unavailable reference pictures . 159
8.3.4 Decoding process for reference picture lists construction . 160
8.3.5 Decoding process for collocated picture and no backward prediction flag . 161
8.4 Decoding process for coding units coded in intra prediction mode . 162
8.4.1 General decoding process for coding units coded in intra prediction mode . 162
8.4.2 Derivation process for luma intra prediction mode . 166
8.4.3 Derivation process for chroma intra prediction mode . 169
8.4.4 Decoding process for intra blocks . 170
8.5 Decoding process for coding units coded in inter prediction mode . 183
8.5.1 General decoding process for coding units coded in inter prediction mode . 183
8.5.2 Inter prediction process . 184
8.5.3 Decoding process for prediction units in inter prediction mode . 187
8.5.4 Decoding process for the residual signal of coding units coded in inter prediction mode220
8.6 Scaling, transformation and array construction process prior to deblocking filter process . 224
8.6.1 Derivation process for quantization parameters . 224
8.6.2 Scaling and transformation process . 226
8.6.3 Scaling process for transform coefficients . 228
8.6.4 Transformation process for scaled transform coefficients . 229
8.6.5 Residual modification process for blocks using a transform bypass . 232
8.6.6 Residual modification process for transform blocks using cross-component prediction 233
8.6.7 Picture construction process prior to in-loop filter process . 233
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8.6.8 Residual modification process for blocks using adaptive colour transform . 234
8.7 In-loop filter process . 236
8.7.1 General . 236
8.7.2 Deblocking filter process . 237
8.7.3 Sample adaptive offset process . 255
9 Parsing process . 258
9.1 General . 258
9.2 Parsing process for 0-th order Exp-Golomb codes . 258
9.2.1 General . 258
9.2.2 Mapping process for signed Exp-Golomb codes . 260
9.3 CABAC parsing process for slice segment data . 260
9.3.1 General . 260
9.3.2 Initialization process . 263
9.3.3 Binarization process . 277
9.3.4 Decoding process flow . 287
9.3.5 Arithmetic encoding process . 303
10 Sub-bitstream extraction process . 309
Annex A (normative) Profiles, tiers and levels . 311
Annex B (normative) Byte stream format . 339
Annex C (normative) Hypothetical reference decoder . 342
Annex D (normative) Supplemental enhancement information . 363
Annex E (normative) Video usability information . 523
Annex F (normative) Common specifications for multi-layer extensions . 552
Annex G (normative) Multiview high efficiency video coding . 708
Annex H (normative) Scalable high efficiency video coding . 733
Annex I (normative) 3D high efficiency video coding . 763
Bibliography . 888

vi © ISO/IEC 2020 – 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent
rights. Details of any patent rights identified during the development of the document will be in the
Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation 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 the following URL:
www.iso.org/iso/foreword.html.
This document was prepared by ISO/IEC JTC 1, Information technology, Subcommittee SC 29, Coding of
audio, picture, multimedia and hypermedia information, in collaboration with ITU-T. The technically
identical text is published as Rec. ITU-T H.265.
This fourth edition cancels and replaces the third edition (ISO/IEC 23008-2:2017), which has been
technically revised. It also incorporates the amendments ISO/IEC 23008-2:2017/Amd 1:2018,
ISO/IEC 23008-2:2017/Amd 2:2018, and ISO/IEC 23008-2:2017/Amd 3:2018).
The main changes compared to the previous edition are:
 the specification of two additional profiles (the Monochrome 10 and Main 10 Still Picture profiles);
 the specification of additional supplemental enhancement information (SEI) messages and
additional colour-related video usability information codepoint identifiers;
 corrections to various minor defects.
A list of all parts in the ISO/IEC 23008 series can be found on the ISO website.
vii
© ISO/IEC 2020 – All rights reserved

Introduction
As the costs for both processing power and memory have reduced, network support for coded video data
has diversified, and advances in video coding technology have progressed. The need has arisen for an
industry standard for compressed video representation with substantially increased coding efficiency
and enhanced robustness to network environments. Toward these ends, the ITU-T Video Coding Experts
Group (VCEG) and the ISO/IEC Moving Picture Experts Group (MPEG) formed a Joint Collaborative Team
on Video Coding (JCT-VC) in 2010 and a Joint Collaborative Team on 3D Video Coding Extension
Development (JCT-3V) in 2012 for development of a new Recommendation | International Standard. This
document was developed in the JCT-VC and the JCT-3V.
Purpose
This document was developed in response to the growing need for higher compression of moving
pictures for various applications such as videoconferencing, digital storage media, television
broadcasting, internet streaming, and communications. It is also designed to enable the use of the coded
video representation in a flexible manner for a wide variety of network environments as well as to enable
the use of multi-core parallel encoding and decoding devices. The use of this document allows motion
video to be manipulated as a form of computer data and to be stored on various storage media,
transmitted and received over existing and future networks and distributed on existing and future
broadcasting channels. Supports for higher bit depths and enhanced chroma formats, including the use
of full-resolution chroma are provided. Support for scalability enables video transmission on networks
with varying transmission conditions and other scenarios involving multiple bit rate services. Support
for multiview enables representation of video content with multiple camera views and optional auxiliary
information. Support for 3D enables joint representation of video content and depth information with
multiple camera views.
Applications
This document is designed to cover a broad range of applications for video content including but not
limited to the following:
— broadcast (cable TV on optical networks / copper, satellite, terrestrial, etc.);
— camcorders;
— content production and distribution;
— digital cinema;
— home cinema;
— internet streaming, download and play;
— medical imaging;
— mobile streaming, broadcast and communications;
— real-time conversational services (videoconferencing, videophone, telepresence, etc.);
— remote video surveillance;
— storage media (optical disks, digital video tape recorder, etc.);
— wireless display.
viii © ISO/IEC 2020 – All rights reserved

Publication and versions of this document
This document has been jointly developed by ITU-T Video Coding Experts Group (VCEG) and the ISO/IEC
Moving Picture Experts Group (MPEG). It is published as technically-aligned twin text in both ITU-T and
ISO/IEC. As the basis text has been drafted to become both an ITU-T Recommendation and an ISO/IEC
International Standard, the term "Specification" (with capitalization to indicate that it refers to the whole
of the text) is used herein when the text refers to itself.
This is the fifth version of this document and the fourth edition published by ISO/IEC.
Rec. ITU-T H.265 | ISO/IEC 23008-2 version 1 refers to the first approved version of this document. The
first edition published by ISO/IEC as ISO/IEC 23008-2:2013 corresponded to the first version.
Rec. ITU-T H.265 | ISO/IEC 23008-2 version 2 refers to the integrated text additionally containing format
range extensions, scalability extensions, multiview extensions, additional supplement enhancement
information, and corrections to various minor defects in the prior content of the specification. The second
edition published by ISO/IEC as ISO/IEC 23008-2:2015 corresponded to the second version.
Rec. ITU-T H.265 | ISO/IEC 23008-2 version 3 refers to the integrated text additionally containing 3D
extensions, additional supplement enhancement information, and corrections to various minor defects
in the prior content of the specification.
Rec. ITU-T H.265 | ISO/IEC 23008-2 version 4 refers to the integrated text additionally containing screen
content coding extensions profiles, scalable range extensions profiles, additional high throughput
profiles, additional supplement enhancement information, additional colour representation identifiers,
and corrections to various minor defects in the prior content of the specification. The third edition
published by ISO/IEC as ISO/IEC 23008-2:2017 corresponded to the fourth version.
Rec. ITU-T H.265 | ISO/IEC 23008-2 version 5 refers to the integrated text additionally containing
additional SEI messages that include omnidirectional video specific SEI messages, a Monochrome 10
profile, a Main 10 Still Picture profile, and corrections to various minor defects in the prior content of the
specification.
Rec. ITU-T H.265 | ISO/IEC 23008-2 version 6 refers to the integrated text additionally containing
additional SEI messages for SEI manifest and SEI prefix, and corrections to various minor defects in the
prior content of the specification.
Rec. ITU-T H.265 | ISO/IEC 23008-2 version 7 (the current version) refers to the integrated text
additionally containing the fisheye video information SEI message and the annotated regions SEI
message, and corrections to various minor defects in the prior content of the specification. The fourth
edition published by ISO/IEC as ISO/IEC 23008-2:2020 corresponds to the fifth version.
Profiles, tiers, and levels
This document is designed to be generic in the sense that it serves a wide range of applications, bit rates,
resolutions, qualities, and services. Applications should cover, among other things, digital storage media,
television broadcasting, and real-time communications. In the course of creating this document, various
requirements from typical applications have been considered, necessary algorithmic elements have been
developed, and these have been integrated into a single syntax. Hence, this document will facilitate video
data interchange among different applications.
Considering the practicality of implementing the full syntax of this document, however, a limited number
of subsets of the syntax are also stipulated by means of "profiles", "tiers", and "levels". These and other
related terms are formally defined in Clause 3.
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A “profile” is a subset of the entire bitstream syntax that is specified in this document. Within the bounds
imposed by the syntax of a given profile it is still possible to require a very large variation in the
performance of encoders and decoders depending upon the values taken by syntax elements in the
bitstream such as the specified size of the decoded pictures. In many applications, it is currently neither
practical nor economical to implement a decoder capable of dealing with all hypothetical uses of the
syntax within a particular profile.
In order to deal with this problem, "tiers" and "levels" are specified within each profile. A level of a tier is
a specified set of constraints imposed on values of the syntax elements in the bitstream. These constraints
may be simple limits on values. Alternatively they may take the form of constraints on arithmetic
combinations of values (e.g. picture width multiplied by picture height multiplied by number of pictures
decoded per second). A level specified for a lower tier is more constrained than a level specified for a
higher tier.
Coded video content conforming to this document uses a common syntax. In order to achieve a subset of
the complete syntax, flags, parameters, and other syntax elements are included in the bitstream that
signal the presence or absence of syntactic elements that occur later in the bitstream.
Overview of the design characteristics
The coded representation specified in the syntax is designed to enable a high compression capability for
a desired image or video quality. The algorithm is typically not lossless, as the exact source sample values
are typically not preserved through the encoding and decoding processes. A number of techniques may
be used to achieve highly efficient compression. Encoding algorithms (not specified in this
Recommendation | International Standard) may select between inter and intra coding for block-shaped
regions of each picture. Inter coding uses motion vectors for block-based inter prediction to exploit
temporal statistical dependencies between different pictures. Intra coding uses various spatial prediction
modes to exploit spatial statistical dependencies in the source signal for a single picture. Motion vectors
and intra prediction modes may be specified for a variety of block sizes in the picture. The prediction
residual may then be further compressed using a transform to remove spatial correlation inside the
transform block before it is quantized, producing a possibly irreversible process that typically discards
less important visual information while forming a close approximation to the source samples. Finally, the
motion vectors or intra prediction modes may also be further compressed using a variety of prediction
mechanisms, and, after prediction, are combined with the quantized transform coefficient information
and encoded using arithmetic coding.
How to read this document
It is suggested that the reader starts with Clause 1 (Scope) and moves on to Clause 3 (Terms and
definitions). Clause 6 should be read for the geometrical relationship of the source, input, and output of
the decoder. Clause 7 (Syntax and semantics) specifies the order to parse syntax elements from the
bitstream. See 7.1 to 7.3 for syntactical order and see 7.4 for semantics; e.g. the scope, restrictions, and
conditions that are imposed on the syntax elements. The actual parsing for most syntax elements is
specified in Clause 9 (Parsing process). Clause 10 (Sub-bitstream extraction process) specifies the sub-
bitstream extraction process. Finally, Clause 8 (Decoding process) specifies how the syntax elements are
mapped into decoded samples. Throughout reading this document, the reader should refer to Clauses 2
(Normative references), 4 (Abbreviations), and 5 (Conventions) as needed. Annexes A through I also form
an integral part of this document.
Annex A specifies profiles each being tailored to certain application domains, and defines the so-called
tiers and levels of the profiles. Annex B specifies syntax and semantics of a byte stream format for delivery
of coded video as an ordered stream of bytes. Annex C specifies the hypothetical reference decoder,
bitstream conformance, decoder conformance, and the use of the hypothetical reference decoder to check
bitstream and decoder conformance. Annex D specifies syntax and semantics for supplemental
x © ISO/IEC 2020 – All rights reserved

enhancement information message payloads. Annex E specifies syntax and semantics of the video
usability information parameters of the sequence parameter set. Annex F specifies general multi-layer
support for bitstreams and decoders. Annex G contains support for multiview coding. Annex H contains
support for scalability. Annex I contains support for 3D coding.
Throughout this document, statements appearing with the preamble "NOTE" are informative and are not
an integral part of this document.
Patent rights identified
The International Organization for Standardization (ISO) and International Electrotechnical Commission
(IEC) draw attention to the fact that it is claimed that compliance with this document may involve the use
of patents.
ISO and IEC take no position concerning the evidence, validity and scope of these patent rights.
The holders of these patent rights have assured ISO and IEC that they are willing to negotiate licences
under reasonable and non-discriminatory terms and conditions with applicants throughout the world. In
this respect, the statements of the holders of these patent rights are registered with ISO and IEC.
Information may be obtained from the patent database available at www.iso.org/patents.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights other than those in the patent database. ISO and IEC shall not be held responsible for
identifying any or all such patent rights.

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INTERNATIONAL STANDARD ISO/IEC 23008-2:2020(E)
Information technology — High efficiency coding and
media delivery in heterogeneous environments —
Part 2:
High efficiency video coding
1 Scope
This document specifies high efficiency video coding.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes 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 11664-1, Colorimetry — Part 1: CIE standard colorimetric observers
ISO 12232, Photography — Digital still cameras — Determination of exposure index, ISO speed ratings,
standard output sensitivity, and recommended exposure index
ISO/IEC 10646, Information technology — Universal Coded Character Set (UCS)
ISO/IEC 11578, Information technology — Open Systems Interconnection — Remote Procedure Call (RPC)
ISO/IEC 23001-11, Information technology — MPEG systems technologies — Part 11: Energy-efficient
media consumption (green metadata)
IETF RFC 1321, The MD5 Message-Digest Algorithm
IETF RFC 5646, Tags for Identifying Languages
Recommendation ITU-T T.35, Procedure for the allocation of ITU-T defined codes for non-standard facilities
CEN/TR 13233, Advanced technical ceramics — Notations and symbols
3 Terms and definitions
For the purposes of this document, the terms and definitions given in CEN/TR 13233 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
© ISO/IEC 2020 – All rights reserved 1

3.1
access unit
set of NAL units (3.87) that are associated with each other according to a specified classification rule,
are consecutive in decoding order (3.44), and contain exactly one coded picture (3.25) with nuh_layer_id
equal to 0
Note 1 to entry: In addition to containing the VCL NAL units (3.181) of the coded picture with nuh_layer_id equal
to 0, an access unit may also contain non-VCL NAL units. The decoding of an access unit with the decoding process
specified in Clause 8 always results in a decoded picture with nuh_layer_id equal to 0.
Note 2 to entry: An access unit is defined differently in Annex F and does not need to contain a coded picture with
nuh_layer_id equal to 0.
3.2
AC transform coefficient
transform coefficient (3.175) for which the frequency index (3.58) in at least one of the two dimensions
is non-zero
3.3
associated IRAP picture
previous IRAP picture (3.71) in decoding order (3.44) (when present)
3.4
associated non-VCL NAL unit
non-VCL NAL unit (3.91) (when present) for a VCL NAL unit (3.180) where the VCL NAL unit is the
associated VCL NAL unit (3.5) of the non-VCL NAL unit
3.5
associated VCL NAL unit
preceding VCL NAL unit (3.180) in decoding order (3.44) for a non-VCL NAL unit (3.91) with nal_unit_
type equal to EOS_NUT, EOB_NUT, FD_NUT, or SUFFIX_SEI_NUT, or in the ranges of RSV_NVCL45.RSV_
NVCL47 or UNSPEC56.UNSPEC63; or otherwise, the next VCL NAL unit in decoding order
3.6
azimuth circle
circle on a sphere connecting all points with the same azimuth value
Note 1 to entry: An azimuth circle is always a great circle like a longitude line on the earth.
3.7
base layer
layer in which all NAL units (3.87) have nuh_layer_id equal to 0
3.8
bin
one bit of a bin string (3.11)
3.9
binarization
set of bin strings (3.11) for all possible values of a syntax element (3.162)
3.10
binarization process
unique mapping process of all possible values of a syntax element (3.162) onto a set of bin strings (3.11)
3.11
bin string
intermediate binary representation of values of syntax elements (3.162) from the binarization (3.9) of
the syntax element
2 © ISO/IEC 2020 – All rights reserved

3.12
bi-predictive slice
B slice
slice (3.143) that is decoded using intra prediction (3.69) or using inter prediction (3.67) with at most
two motion vectors (3.86) and reference indices (3.127) to predict the sample values of each block (3.14)
3.13
bitstream
sequence of bits, in the form of a NAL unit stream (3.88) or a byte stream (3.21), that forms the
representation of coded pictures (3.25) and associated data forming one or more CVSs (3.30)
3.14
block
MxN (M-column by N-row) array of samples or an MxN array of transform coefficients (3.175)
3.15
broken link
location in a bitstream (3.13) at which it is indicated that some subsequent pictures (3.99) in decoding
order (3.44) may contain serious visual artefacts due to unspecified operations performed in the
generation of the bitstream
3.16
broken link access access unit
BLA access unit
access unit (3.1) in which the coded picture (3.25) with nuh_layer_id equal to 0 is a BLA picture (3.17)
3.17
broken link access picture
BLA picture
IRAP picture (3.71) for which each VCL NAL unit (3.181) has nal_unit_type equal to BLA_W_LP, BLA_W_
RADL, or BLA_N_LP
Note 1 to entry: A BLA picture does not refer to any pictures other than itself for inter prediction (3.67) in its
decoding process (3.45), and may be the first picture in the bitstream (3.13) in decoding order, or may appear
later in the bitstream. Each BLA picture begins a new CVS (3.30), and has the same effect on the decoding process
as an IDR picture (3.65). However, a BLA picture contains syntax elements (3.162) that specify a non-empty RPS
(3.132). When a BLA picture for which each VCL NAL unit has nal_unit_type equal to BLA_W_LP, it may have
associated RASL pictures, which are not output by the decoder and may not be decodable, as they may contain
references to pictures that are not present in the bitstream. When a BLA picture for which each VCL NAL unit has
nal_unit_type equal to BLA_W_LP, it may also have associated RADL pictures, which are specified to be decoded.
When a BLA picture for which each VCL NAL unit has nal_unit_type equal to BLA_W_RADL, it does not have
associated RASL pictures but may have associated RADL pictures. When a BLA picture for which each VCL NAL
unit has nal_unit_type equal to BLA_N_LP, it does not have any associated leading pictures.
3.18
buffering period
set of access units (3.1) starting with an access unit that contains a buffering period SEI message and
containing all subsequent access units in decoding order (3.44) up to but not including the next access
unit (when present) that contains a buffering period SEI message
3.19
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
3.20
byte-aligned
position in a bitstream (3.13) is byte-aligned when the position is an integer multiple of 8 bits from the
position of the first bit in the bitstream and a bit or byte (3.19) or syntax element (3.162) is said to be
byte-aligned when the position at which it appears in a bitstream is byte-aligned
© ISO/IEC 2020 – All rights reserved 3

3.21
byte stream
sequence of bytes forming an encapsulation of a NAL unit stream (3.88) into a format containing start
code prefixes (3.150) and NAL units (3.87)
Note 1 to entry: See Annex B.
3.22
chroma
Cb
Cr
sample array or single sample representing one of the two colour difference signals related to the
primary colours
Note 1 to entry: The term chroma is used rather than the term chrominance in order to avoid the implication of
the use of linear light transfer characteristics that is often associated with the term chrominance.
3.23
clean random access access unit
CRA access unit
access unit (3.1) in which the coded picture (3.25) with nuh_layer_id equal to 0 is a CRA picture (3.24)
3.24
clean random access picture
CRA picture
IRAP picture (3.71) for which each VCL NAL unit (3.181) has nal_unit_type equal to CRA_NUT
Note 1 to entry: A CRA picture does not refer to any pictures other than itself for inter prediction in its decoding
process, and may be the first picture in the bitstream in decoding order, or may appear later in the bitstream.
A CRA picture may have associated RADL or RASL pictures. As with a BLA picture, a CRA picture may contain
syntax elements that specify a non-empty RPS (3.131). When a CRA picture has NoRaslOutputFlag equal to 1, the
associated RASL pictures are not output by the decoder, because they may not be decodable, as they may contain
references to pictures that are not present in the bitstream.
3.25
coded picture
coded representation of a picture containing all CTUs (3.34) of the picture
3.26
coded picture buffer
CPB
first-in first-out buffer containing decoding units (3.46) in decoding order (3.44) specified in the
hypothetical reference decoder (3.56)Note 1 to entry: The hypothetical reference decoder is defined in
Annex C.
3.27
coded representation
data element as represented in its coded form
3.28
coded slice segment NAL unit
NAL unit (3.87) that has nal_unit_type in the range of TRAIL_N to RASL_R, inclusive, or in the range
of BLA_W_LP to RSV_IRAP_VCL23, inclusive, which indicates that the NAL unit contains a coded slice
segment (3.145)
3.29
coded layer-wise video sequence
CLVS
sequence of pictures (3.99) and the associated non-VCL NAL units (3.91) of the base layer of a CVS (3.30)
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3.30
coded video sequence
CVS
sequence of access units (3.1) that consists, in decoding order (3.44), of an IRAP access unit (3.65) with
NoRaslOutputFlag equal to 1, followed by
...