ISO/IEC 21122-2:2022

INTERNATIONAL ISO/IEC
STANDARD 21122-2
Second edition
2022-03
Information technology — JPEG XS
low-latency lightweight image coding
system —
Part 2:
Profiles and buffer models
Technologies de l'information — Système de codage d'images léger à
faible latence JPEG XS —
Partie 2: Profils et modèles tampons
Reference number
© ISO/IEC 2022
© ISO/IEC 2022
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© ISO/IEC 2022 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms . 4
3.3 Symbols . 4
4 Conventions . 6
4.1 Conformance language . 6
4.2 Operators . 6
4.2.1 Arithmetic operators . 6
4.2.2 Logical operators . 6
4.2.3 Relational operators . 6
4.2.4 Precedence order of operators . 6
4.2.5 Mathematical functions . 7
5 Buffer model . 7
5.1 General system block diagram . 7
5.2 Influencing variables on the required buffer sizes . 8
5.3 Role of the buffer model . 9
6 Interpretation of Bayer data . 9
Annex A (normative) Profiles, levels and sublevels .11
Annex B (normative) Packet-based JPEG XS decoder model .25
Annex C (normative) Packet-based constant bit rate buffer model .31
Annex D (informative) Encoder model, latency bounds and codestream conformance
properties for the packet-based constant bit rate buffer model .37
Annex E (informative) JPEG XS latency analysis .42
Bibliography .49
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© ISO/IEC 2022 – 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).
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) or the IEC
list of patent declarations received (see patents.iec.ch).
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 21122-2:2019), which has been
technically revised.
The main changes are as follows:
— addition of new profiles to compress colour filter array images (CFA images), to allow mathematically
lossless image compression, and to compress 4:2:0 colour sampled images.
A list of all parts in the ISO/IEC 21122 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.
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© ISO/IEC 2022 – All rights reserved

Introduction
This document is part of a series of standards for a low-latency lightweight image coding system,
denoted as JPEG XS.
While ISO/IEC 21122-1 specifies a full set of compression coding tools needed to satisfy all of the
requirements of JPEG XS, a targeted application can often work with a simpler and reduced set
of coding tools, and with or without tighter constraints, to meet its targeted goals. For this reason,
profiles, levels, and sublevels are defined in this document. These three concepts facilitate partial and
reduced complexity implementations of ISO/IEC 21122-1 for such specific application use cases, while
also safeguarding interoperability.
This document specifies a limited number of profiles to represent interoperability subsets of the
codestream syntax specified in ISO/IEC 21122-1 with each profile serving specific application use
cases. In other word, profiles select a subset of the available coding tools. In addition, levels and
sublevels provide limits to the maximum throughput in respectively the encoded (codestream) and the
decoded (spatial/pixel) domains. In this way, profiles, levels and sublevels allow designing cost-efficient
implementations that serve the needs of the desired applications.
In addition to being light-weight, another major requirement of JPEG XS is to allow low end-to-end
latency, limited to a fraction of the frame size. To ensure this low-latency property, this document
also specifies a buffer model, consisting of a decoder model and a transmission channel model. The
models show the interaction of a hypothetical reference decoder, including its smoothing buffer with a
constant bitrate channel feeding this buffer. The size of the decoder smoothing buffer is computed from
the profile, level, and sublevel. Codestreams are formed such that the buffer of a decoder, operating
according to this buffer model, never overflows or underflows. In effect, the buffer model provides
encoders with the necessary information to generate codestreams that can be decoded by an arbitrary
decoder implementation, ensuring system interoperability.
In addition to the size of the decoder smoothing buffer, end-to-end latency also depends on the latency
inherent to each processing step of the encoding-decoding chain whose methods are described in
ISO/IEC 21122-1. To help implementers estimate the latency of their device, this document gives extra
information on the minimum latency that can be achieved by the different methods described in
ISO/IEC 21122-1.
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© ISO/IEC 2022 – All rights reserved

INTERNATIONAL STANDARD ISO/IEC 21122-2:2022(E)
Information technology — JPEG XS low-latency lightweight
image coding system —
Part 2:
Profiles and buffer models
1 Scope
This document defines a number of subsets of the syntax specified in ISO/IEC 21122-1 as profiles. It
also defines lower bounds on the throughput in the decoded domain via levels and the encoded domain
via sublevels that a conforming decoder implementation shall support. Furthermore, it defines a buffer
model to ensure interoperability between implementations in the presence of a latency constraint.
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/IEC 21122-1, JPEG XS low-latency lightweight image coding system — Part 1: Core coding system
3 Terms, definitions, symbols and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 21122-1 and the following
apply.
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/
3.1.1
blanking codestream fragment
placeholder codestream fragment representing blanking periods
3.1.2
buffer model
combination of a decoder model and a channel model whose behaviour can be defined by a set of
parameters
3.1.3
buffer model instance
specific configuration of a buffer model specified by the assignment of well-defined values to the buffer
model parameters
3.1.4
channel model
model describing the temporal behaviour of the transmission channel connecting an encoder and a
decoder
© ISO/IEC 2022 – All rights reserved

3.1.5
coded codestream fragment
continuous sequence of bits in the codestream containing exactly one packet body and a well-defined
number of packet headers, markers and marker segments
3.1.6
codestream fragment
either coded codestream fragment, or blanking codestream fragment
3.1.7
cycle
single clock period of an encoder or decoder clocked implementation
3.1.8
decoder model
combination of a decoder unit and a decoder smoothing buffer
3.1.9
decoder smoothing buffer
memory buffer that is used to level out changes in the number of bits read by a decoder unit per time
unit
3.1.10
decoder unit
module reading a variable number of bits per time unit to generate decoded output pixels with a fixed
rate
3.1.11
decomposition level
set of wavelet coefficients resulting from a particular level of recursive application of a wavelet
transform
3.1.12
encoder model
combination of an encoder unit and an encoder smoothing buffer
3.1.13
encoder smoothing buffer
memory buffer that is used to level out changes in the number of bits generated by an encoder unit per
time unit
3.1.14
encoder unit
module transforming a sequence of input pixels with constant rate into a conforming codestream,
producing a bit sequence with variable number of bits generated per time unit
3.1.15
fill level
number of bits stored in the encoder or decoder smoothing buffer
3.1.16
horizontal blanking period
timespan expressed in units of the grid point sampling rate between the last pixel of an image line ― not
being the last line of an image ― and the first pixel of the next image line
© ISO/IEC 2022 – All rights reserved

3.1.17
level
defined set of constraints on the amount of decoded samples to be processed by an encoder or decoder,
both in the spatial and time dimensions
Note 1 to entry: The same set of levels is defined for all profiles. Individual implementations may, within the
specified constraints, support a different level for each supported profile.
3.1.18
nominal bits per pixel value
mean number of bits allocated per encoded pixel which is used to derive the sublevel constraints by
assuming an image with well-defined dimensions and frame rate derived from the level
3.1.19
profile
specified subset of the codestream syntax together with admissible parameter values
3.1.20
sampling grid point
position on the sample grid, specified by integer horizontal and vertical offset relative to the origin of
the sample grid
3.1.21
smoothing buffer unit
level and sublevel dependent number of bits by which the smoothing buffer size of the decoder model is
specified
3.1.22
start of transmission
SoT
time at which the transmission channel starts transmission relative to the start of encoding of the first
codestream fragment of a codestream
3.1.23
sublevel
defined set of constraints on the amount of codestream bits to be processed by an encoder or decoder,
per unit of time, per column, and per image
Note 1 to entry: The same set of sublevels is defined for all profiles. Individual implementations may, within the
specified constraints, support a different sublevel for each supported profile.
3.1.24
transmission channel
facility transferring bits from a source entity to a target entity
3.1.25
transmission channel capacity
maximum number of bits per time unit that a transmission channel can transfer from a source entity to
a target entity
3.1.26
vertical blanking period
timespan in units of the grid point sampling rate between the last line of an image ― including the
horizontal blanking periods ― and the first line of the next image
© ISO/IEC 2022 – All rights reserved

3.2 Abbreviated terms
bpp bits per pixel
CFA colour filter array
DWT discrete wavelet transform
IDWT inverse discrete wavelet transform
RCT reversible colour transform
IRCT inverse reversible colour transform
3.3 Symbols
C(i) codestream i
D number of clock cycles between the first bit written into the decoding smoothing buffer and
c2d
the decoding start of the first codestream fragment of a stream of codestream fragments
F (C(i)) first codestream fragment of codestream C(i)
first
F (C(i)) last codestream fragment of codestream C(i)
last
H height of the image in sampling grid points
f
H maximum picture height in sampling grid points
max
L maximum number of sampling grid points per image
max
l (t) fill level of the encoding smoothing buffer in bits at the end of cycle t
enc
l (t) fill level of the decoding smoothing buffer in bits at the end of cycle t
dec
l capacity in bits of the encoding smoothing buffer
enc,max
l capacity in bits of the decoding smoothing buffer
dec,max
Ĩ (t) number of bits that can be read from the decoding smoothing buffer in cycle t
dec
l (t) sum of encoder and decoder smoothing buffer fill level in bits at cycle t
sum

all integer numbers being strictly larger than zero
 all integer numbers being greater than or equal to zero
N size of the horizontal blanking line in sampling grid point clock periods
b,x
N size of the vertical blanking period in sampling grid lines
b,y
N nominal number of bits allocated per pixel for compression
bpp
N number of components in an image
c
N ( f ) number of coefficient groups within codestream fragment f
cg
N number of coefficient groups associated to a codestream fragment representing a hori-
cg,hz
zontal blanking period
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N number of coefficient groups associated to a codestream fragment representing a vertical
cg,vt
blanking period
N (i) number of codestream fragments within a codestream i
f
N number of coefficients in a code group
g
N number of horizontal decomposition levels
L,x
N number of vertical decomposition levels
L,y
N number of precincts per sampling grid line
p,x
N number of precincts per sampling grid column
p,y
N number of decoder smoothing buffer units for a given profile
sbu
ℚ set of rational numbers
r (t) number of bits read and removed from the decoder smoothing buffer in clock cycle t
dec
R transmission channel capacity, expressed in bits per cycle (having a duration of T)
trans
R (l , l ) maximum admissible encoded throughput in bits per second for a given level
t,max m s
R maximum grid point sample rate (in samples per second) at decoder output
s,max
S ( f ) number of bits forming the codestream fragment f
bits
S targeted maximum number of bytes of an encoded codestream
c,max
S (l , l ) size of the smoothing buffer unit in bytes for level l and sublevel l
sbu m s m s
S (p) smoothing buffer offset in bits for a profile p
sbo
S (l , l ) maximum size of an encoded codestream in bytes of level l and sublevel l
sl,max m s m s
s [i] sampling factor of component i in horizontal direction
x
s [i] sampling factor of component i in vertical direction
y
T clock period defining the frequency by which code groups are processed by an encoder
enc
T clock period defining the frequency by which code groups are processed by a decoder
dec
t ( f ) timestamp in cycles at which the codestream fragment f is written to the encoder smooth-
enc,write
ing buffer
t ( f ) timestamp in cycles at which decoder starts decoding codestream fragment f
dec,start
t ( f ) timestamp in cycles at which codestream fragment f is removed from the decoder smooth-
dec,read
ing buffer
Tbmd buffer model type
W [i] width of component i in samples
c
W maximum column width in sampling grid points for a given profile
c,max
w (t) number of bits written into the decoder smoothing buffer in clock cycle t
dec
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W width of the image in sampling grid points
f
W maximum picture width in sampling grid points
max

set of all integer numbers
4 Conventions
4.1 Conformance language
The keyword "reserved" indicates a provision that is not specified at this time, shall not be used, and
may be specified in the future. The keyword "forbidden" indicates "reserved" and in addition indicates
that the provision will never be specified in the future.
4.2 Operators
NOTE Many of the operators used in document are similar to those used in the C programming language.
4.2.1 Arithmetic operators
+ addition
− subtraction (as a binary operator) or negation (as a unary prefix operator)
× multiplication
/ division without truncation or rounding
4.2.2 Logical operators
|| logical OR
&& logical AND
! logical NOT
4.2.3 Relational operators
> greater than
≥ greater than or equal to
< less than
≤ less than or equal to
== equal to
!= not equal to
4.2.4 Precedence order of operators
Operators are listed in descending order of precedence. If several operators appear in the same line,
they have equal precedence. When several operators of equal precedence appear at the same level in an
expression, evaluation proceeds according to the associativity of the operator either from right to left
or from left to right.
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Operators Type of operation Associativity
() expression left to right
[] indexing of arrays left to right
– unary negation
×, / multiplication, division left to right
+, − addition and subtraction left to right
< , >, ≤, ≥ relational left to right
& bitwise AND left to right
| bitwise OR left to right
4.2.5 Mathematical functions
x
  ceil of x: returns the smallest integer that is greater than or equal to x
 
x
floor of x: returns the largest integer that is less than or equal to x
 
|x| absolute value of x, |x| equals –x for x < 0, otherwise x
sign(x) sign of x, 0 if x is 0, +1 if x is positive, −1 if x is negative
10t ≥

ξ t
() step function ξ t =
()

0otherwise

max (x ) maximum of a sequence of numbers [x ] enumerated by the index i
i i i
5 Buffer model
5.1 General system block diagram
The JPEG XS coding system addresses applications where coded images are transferred from a source
to a target, as shown in Figure 1. To this end, the encoder is compressing a continuous stream of input
pixels into a sequence of bits. These bits are forwarded by means of a transmission channel to the
decoder that decompresses the bits to produce a continuous stream of output pixels.
© ISO/IEC 2022 – All rights reserved

Key
1 encoder clock 6 decoder smoothing buffer
2 pixel data 7 decoder unit
3 encoder unit 8 decoder clock
4 encoder smoothing buffer 9 variable bit rate
5 transmission channel
Figure 1 — General system block diagram
The time instances at which the encoder processes each pixel are determined by an encoding clock.
Similarly, the time instances at which the decoder produces each output pixel are determined by a
decoding clock. Both clocks are generated by the system.
NOTE In implementations, these clocks can be the same or differ in both frequency and phase. The presented
model is independent of whether clocks are synchronized or not.
In accordance with ISO/IEC 21122-1, the pixels of an image are translated into coefficient groups
represented as code groups in the codestream. The number of bits necessary to code these code groups
may vary from group to group. As a consequence, the encoder writes encoded bits at a variable rate into
the encoder smoothing buffer. Similarly, the decoder reads the codestream at a variable rate from the
decoder smoothing buffer.
In case the maximum bit rate of the transmission channel is below the peak bit rate generated by the
encoder, an encoder smoothing buffer is necessary to decouple generation of bits by the encoder from
transmission of bits over the transmission channel. Similarly, a decoder smoothing buffer needs to be
provided that decouples the arrival of bits at the rate afforded by the transmission channel and the
consumption of bits by the decoder per clock.
Correct operation requires that the decoder buffer never overflows. This is because the decoder is
not able to pause the arrival of bits from the transmission channel. Moreover, a buffer underflow in
the decoder buffer needs to be avoided. This is because the decoder is required to output pixels in
accordance with the timing of its output interface. Hence it needs to be ensured that the bits to be read
from the decoding buffer to produce the next pixel in accordance with the decoding clock are available
in this decoding buffer.
5.2 Influencing variables on the required buffer sizes
Avoiding any buffer overflow or underflow, as discussed in subclause 5.1, requires sizing the decoder
smoothing buffer properly. Moreover, the time at which decoding starts is delayed relative to the
starting time of encoding and the start of transmission needs to be carefully set. Those values are
influenced by many system parameters, for example:
— The maximum transmission channel bit rate.
— The granularity at which the encoder writes the encoded data and the decoder reads the encoded
data.
© ISO/IEC 2022 – All rights reserved

— The rate control strategy applied by the encoder.
These dependencies cause that encoders and decoders are only interoperable in well-defined conditions.
Defining these conditions is the purpose of the buffer model defined in Annex B and Annex C.
5.3 Role of the buffer model
The core coding system defined in ISO/IEC 21122-1 can be implemented on a large variety of platforms
using many different implementation strategies. Thus, interoperability cannot be achieved by precisely
specifying the temporal behaviour of a conforming decoding implementation. Instead, the buffer model
defines a simplified decoder model. Interoperability is then achieved by mandating that a conforming
decoder shall decode all bit streams being decodable by the simplified decoder model. Similarly, a
conforming encoder shall not create bit streams that cannot be decoded by the simplified decoder
model.
To this end, Annex B defines a generic JPEG XS decoder model that precisely defines the temporal
behaviour of the decoder model assuming a processing granularity of codestream packets. While such
a model already defines some fundamental properties of the decodable codestreams, it is still not
sufficient to ensure interoperability. The reason is that otherwise codestreams could be constructed
that would only be decodable by the decoder model if the transmission channel could transport bits
arbitrarily fast. In practice, this is obviously not the case. Consequently, interoperability also requires
defining a channel model over which an encoder sends the codestreams to the decoder.
Annex C defines such a channel model assuming a transmission channel with a fixed upper bit
rate that is related to the target compression ratio. Together with the decoder model of Annex B, it
defines the packet-based constant bit rate buffer model. It describes the conditions for a low latency
interoperability between any conforming encoder and any decoder. These conditions are expressed by
buffer model parameters that are specified by the profiles and levels defined in Annex A. The properties
of such conforming implementations are exemplified in Annex D. Since these properties are direct
consequences of Annex B and Annex C, Annex D is informative only.
6 Interpretation of Bayer data
ISO/IEC 21122-1 defines coding tools and signalling for compression of Bayer-type CFA image data.
According to this specification, each sampling grid point represents a super-pixel of four sensor elements
containing at least one sample of each component. Thus Bayer data is interpreted as an image having
four components, where each sampling grid point describes four spatially disjoint sensor elements (one
element per Bayer channel).
© ISO/IEC 2022 – All rights reserved

Squares represent individual sensor elements and circles represent sampling grid points. Groups of four sensor
elements overlapping with the same sampling grid point form one super-pixel.
Figure 2 — Example of the interpretation of a GRBG Bayer-type CFA image
Moreover, regardless of the Bayer sensor spatial subpixel arrangement, the Star-Tetrix color transform
of ISO/IEC 21122-1 defines a strict order on the components assigning the red channel to component 0,
the green channels to components 1 and 2, and the blue channel to component 3. The spatial subpixel
arrangement is signalled by the CRG marker. Figure 2 shows only one of the four potential subpixel
arrangements of a Bayer-type CFA.
© ISO/IEC 2022 – All rights reserved

Annex A
(normative)
Profiles, levels and sublevels
A.1 General
Profiles, levels and sublevels specify restrictions on codestreams and hence limits on the capabilities
needed to decode the codestreams. Profiles, levels and sublevels may also be used to indicate
interoperability points between individual decoder implementations.
Each profile specifies a subset of algorithmic features and limits on their parameterization that shall
be supported by all decoders conforming to that profile. Encoders are not required to make use of all
features supported in a profile.
The combination of a level and a sublevel defines a lower bound on the throughput a conforming decoder
implementation shall support. To this end, the level gives upper bounds for the image parameters in the
decoded domain, namely the maximum image width, the maximum image height and the maximum
number of sampling grid points to be processed per second.
The sublevel defines upper bounds in the coded domain, such as the nominal bits per pixel value
allocated for an encoded image having maximum width and height. In combination with the constraints
set by the levels in the decoded domain, this allows the derivation of upper bounds on the admissible
encoded image size and the upper number of bits a decoder is required to decode per second. Moreover,
it defines the decoder smoothing buffer unit, whose size is specified in subclause A.4.1.
By these means, the decoding smoothing buffer size can be derived from the profile. In combination
with the tool selection performed by a profile, this allows to control the complexity of a decoder
implementation.
Figure A.1 depicts the relation between level, sublevel, profile and the corresponding constraints they
impose.
© ISO/IEC 2022 – All rights reserved

Figure A.1 — Relationship between the different conformance constraints and the impact on
the decoder complexity
A.2 Profiles
A.2.1 Definitions of profiles
Profiles specify subsets of coding tools which conforming decoders shall support. Moreover, profiles
limit the permitted parameter values. Consequently, profiles are differentiated along the following
features:
— decoder smoothing buffer size expressed in smoothing buffer units (N );
sbu
— smoothing buffer offset (S );
sbo
— component bit precision (B[i]);
— internal precision (Bw, see ISO/IEC 21122-1);
— number of fractional bits for DWT coefficients (Fq, see ISO/IEC 21122-1);
— non-linear transform;
— raw-mode selection per packet flag (Rl, see ISO/IEC 21122-1);
— chroma sampling formats;
— colour transformation (Cpih, see ISO/IEC 21122-1);
— size and extent of the colour tranformation (Cf, see ISO/IEC 21122-1) ;
— number of vertical wavelet decompositions;
— number of horizontal wavelet decompositions ;
— number of components for which to suppress the wavelet decomposition (Sd, see ISO/IEC 21122-1);
© ISO/IEC 2022 – All rights reserved

— supported quantizer types (Qpih, see ISO/IEC 21122-1);
— maximum column width (Cw, see ISO/IEC 21122-1);
— slice height
— buffer model (Tbmd)
— long precinct header enforcement flag (Lh, see ISO/IEC 21122-1).
NOTE 1 The smoothing buffer unit size is determined by the maximum column width in Light-Subline profile
and the maximum image width in other profiles. See Formulae (A.3) and (A.4).
NOTE 2 The commonly used value of 1024 bits (128 bytes) has been derived from a typical size of the picture
header without any extension markers.
NOTE 3 The size and extent of the colour transformation is signalled in the CTS marker when Cpih is set to 3
(see ISO/IEC 21122-1). For other values of Cpih, the CTS marker is not present.
NOTE 4 As defined in ISO/IEC 21122-1, the number of vertical wavelet decompositions is always lower than or
equal to the number of horizontal wavelet decompositions.
N
Lx,

82××Cw max,()si[] ×>if Cw 0
x

i
NOTE 5 The column width in sampling grid points is given by


W otherwise
f

where Cw is indicated in the picture header (see ISO/IEC 21122-1), W is the image width, s [i] is the sampling
f x
factor for component i, and N is the number of horizontal wavelet decompositions.
L,x
NOTE 6 Tbmd = 2 includes Tbmd = 1. This means that a decoder that supports Tbmd = 2 automatically also
supports Tbmd = 1.
For all profiles, the bit precision B[i] (0 ≤ i < N ) of all components, shall be identical.
c
Profile settings that allow the choice between more than one value shall always be selected in
accordance with ISO/IEC 21122-1.
Table A.1, Table A.2, Table A.3, Table A.4, and Table A.5 list all of the profiles specified in this document.
Table A.1 — JPEG XS Main profiles
Profile Main Main Main Main
420.12 422.10 444.12 4444.12
Number N of smoothing buffer units of 16 16 16 16
sbu
the decoder model
Smoothing buffer offset S in bits 1 024 1 024 1 024 1 024
sbo
Component bit precision (B[i]) 8, 10, 12 8, 10 8, 10, 12 8, 10, 12
Internal precision (Bw) 20 20 20 20
# fractional bits for DWT coefficients (Fq) 8 8 8 8
Non-linear transform Disallowed Disallowed Disallowed Disallowed
Raw-mode selection per packet flag (Rl) 0 0 0 0
Chroma sampling formats 4:2:0 4:0:0 4:0:0 4:0:0
4:2:2 4:2:2 4:2:2
4:4:4 4:4:4
4:2:2:4
4:4:4:4
a
One column of full width if number of vertical decompositions larger than 0, otherwise any column width conforming
with ISO/IEC 21122-1 is allowed.
© ISO/IEC 2022 – All rights reserved

Table A.1 (continued)
Profile Main Main Main Main
420.12 422.10 444.12 4444.12
Colour transformation (Cpih) 0 (None) 0 (None) 0 (None) for 0 (None) for
any sampling any sampling
format, or op- format, or op-
tionally tionally
1 (RCT) for 1 (RCT) for
4:4:4 4:4:4 and
4:4:4:4
Number of vertical decompositions 1 0, 1 0, 1 0, 1
Number of horizontal decompositions [1-5] [1-5] [1-5] [1-5]
Number components with suppressed 0 0 0 0
decomposition (Sd)
Quantizer type (Qpih) 0 (DZQ) 0 (DZQ) 0 (DZQ) 0 (DZQ)
1 (Uniform) 1 (Uniform) 1 (Uniform) 1 (Uniform)
Column mode (Cw) One column One column One column One column
of full width except when except when except when
the number the number of the number of
of vertical vertical decom- vertical decom-
decomposition position levels position levels
a a a
levels is zero is zero is zero
Slice height in number of image rows 16 16 16 16
Buffer model (Tbmd) 1, 2 1, 2 1, 2 1, 2
Long precinct header enforcement flag 0 0 0 0
(Lh)
a
One column of full width if number of vertical decompositions larger than 0, otherwise any column width conforming
with ISO/IEC 21122-1 is allowed.
Table A.2 — JPEG XS Light profiles
Profile Light Light Light-Subline
422.10 444.12 422.10
Number N of smoothing buffer units of the decoder 4 4 2
sbu
model
Smoothing buffer offset S in bits 1 024 1 024 1 024
sbo
Component bit precision (B[i]) 8, 10 8, 10, 12 8, 10
Internal precision (Bw) 20 20 20
# fractional bits for DWT coefficients (Fq) 8 8 8
Non-linear transform Disallowed Disallowed Disallowed
Raw-mode selection per packet flag (Rl) 0 0 0
Chroma sampling formats 4:0:0 4:0:0 4:0:0
4:2:2 4:2:2 4:2:2
4:4:4
Colour transformation 0 (None) 0 (None) for 0 (None)
any sampling
format, or
optionally
1 (RCT) for
4:4:4
Number of vertical decompositions 0, 1 0, 1 0
Number of horizontal decompositions [1-5] [1-5] [1-5]
Number components with suppressed decomposition (Sd) 0 0 0
© ISO/IEC 2022 – All rights reserved

Table A.2 (continued)
Profile Light Light Light-Subline
422.10 444.12 422.10
Quantizer type (Qpih) 0 (DZQ) 0 (DZQ) 0 (DZQ)
1 (Uniform)
Column mode (Cw) Only one col- Only one col- Maximum
umn permit- umn permit- column width
ted ted of 2 048 grid
(full width) (full width) points
Slice height in number of image rows 16 16 16
Buffer model (Tbmd) 1, 2 1, 2 1, 2
Long precinct header enforcement flag (Lh) 0 0 0
Table A.3 — JPEG XS High profiles
Profile High High
444.12 4444.12
Number N of smoothing buffer units of the decoder model 16 16
sbu
Smoothing buffer offset S in bits 1 024 1 024
sbo
Component bit precision (B[i]) 8, 10, 12 8, 10, 12
Internal precision (Bw) 20 20
# fractional bits for DWT coefficients (Fq) 8 8
Non-linear transform Disallowed Disallowed
Raw-mode selection per packet flag (Rl) 0 0
Chroma sampling formats 4:0:0 4:0:0
4:2:2 4:2:2
4:4:4 4:4:4
4:2:2:4
4:4:4:4
Colour transformation 0 (None) for 0 (None) for
any sampling for- any sampling for-
mat, or optionally mat, or optionally
1 (RCT) for 4:4:4 1 (RCT) for 4:4:4
and 4:4:4:4
Number of vertical decompositions 0, 1, 2 0, 1, 2
Number of horizontal decompositions [1-5] [1-5]
Number components with suppressed decomposition (Sd) 0 0
Quantizer type (Qpih) 0 (DZQ) 0 (DZQ)
1 (Unform) 1 (Unform)
Column mode (Cw) One column except One column except
when the number when the number of
of vertical decom- vertical decomposi-
a
position levels is tion levels is zero
a
zero
Slice height in number of image rows 16 16
Buffer model (Tbmd) 1, 2 1, 2
Long precinct header enforcement flag (Lh) 0 0
a
One column of full width if number of vertical decompositions larger than 0, otherwise any column width conforming
with ISO/IEC 21122-1 is allowed.
© ISO/IEC 2022 – All rights reserved

Table A.4 — JPEG XS MLS profiles
Profile MLS.12
Number N of smoothing buffer units of the decoder model Unconstrained
sbu
Smoothing buffer offset S in bits n.a.
sbo
Component bit precision (B[i]) 8, 10, 12
Internal precision (Bw) Component precision
# fractional bits for DWT coefficients (Fq) 0
Non-linear transform Disallowed
Raw-mode selection per packet flag (Rl) 0
Chroma sampling formats 4:0:0
4:2:0
4:2:2
4:4:4
4:2:2:4
4:4:4:4
Colour transformation 0 (None) for
any sampling format, or
optionally
1 (RCT) for 4:4:4 and
4:4:4:4
b
Number of vertical decompositions 0 (except for 4:2:0), 1, 2
Number of horizontal decompositions [1-5]
Number components with suppressed decomposition (Sd) 0
Quantizer type (Qpih) 0 (DZQ)
1 (Uniform)
Column mode (Cw) One column except when
the number of vertical
decomposition levels is
a
zero
Slice height in number of image rows 16
Buffer model (Tbmd) 0 (Unconstrained)
Long precinct header enforcement flag (Lh) 0
a
One column of full width if number of vertical decompositions larger than 0, otherwise any column
width conforming with ISO/IEC 21122-1 is allowed.
b
Conforming with ISO/IEC 21122-1, zero (0) vertical decompositions cannot be used in combination
with 4:2:0 chroma sampling.
© ISO/IEC 2022 – All rights reserved

Table A.5 — JPEG XS Bayer profiles
Profile LightBayer MainBayer HighBayer
Number N of smoothing buffer units of the decoder 4 8 16
sbu
model
Smoothing buffer offset S in bits 1 024 1 024 1 024
sbo
Component bit precision (B[i]) 10, 12, 14, 16 10, 12, 14, 16 10, 12, 14, 16
Internal precision (Bw) 18 if an NLT is 18 if an NLT is 18 if an NLT is
used, used, used,
20 if no NLT is 20 if no NLT is 20 if no NLT is
a a a
used used used
# fractional bits for DWT coefficients (Fq) 6 if Bw is 18, 6 if Bw is 18, 6 if Bw is 18,
b b b
8 if Bw is 20 8 if Bw is 20 8 if Bw is 20
Non-linear transform None, None, None,
Quadratic, Quadratic, Quadratic,
Extended Extended Extended
c
Raw-mode selection per packet flag (Rl) 1 1 1
Chroma sampling formats Bayer pattern Bayer pattern Bayer pattern
interpreted as interpreted as interpreted as
4-dimensional 4-dimensional 4-dimensional
vectors vectors vectors
Colour transformation (Cpih) 3 (Star-Tetrix) 3 (Star-Tetrix) 3 (Star-Tetrix)
Size and extent of the colour transformation (Cf) 3 (Inline) 0 (Full), 0 (Full),
3 (Inline) 3 (Inline)
Number of vertical decompositions 0 0, 1 0, 1, 2
Number of horizontal decompositions [1-5] [1-5] [1-5]
Number components with suppressed decomposition 1 1 1
(Sd)
Quantizer type (Qpih) 0 (DZQ) 0 (DZQ) 0 (DZQ)
1 (Uniform) 1 (Uniform) 1 (Uniform)
Column mode (Cw) Disallowed Disallowed Disallowed
Slice height in number of image rows 16 16 16
Buffer model (Tbmd) 1, 2 1, 2 1, 2
Long precinct header enforcement flag (Lh) 0, 1 0, 1 0, 1
a
The internal precision (Bw) is selected in conformance with ISO/IEC 21122-1. The value 20 is used when the non-linear
transform is not used (i.e. no NLT is marker is present), otherwise the value 18 is used.
b
The number of fractional bits for DWT coefficients (Fq) is selected as specified in ISO/IEC 21122-1. The value 6 is used
when Bw is set to 18, while the value 8 is used when Bw is set to 20.
c
In this profile, with zero vertical decompositions, the raw-mode selection per packet flag will not influence the
resulting codestream. However, it is set to 1 to match with the MainBayer and HighBayer profiles.
Figure A.2 represents the relation of the profiles defined in Table A.1, Table A.2, Table A.3, Table A.4, and
Table A.5 in terms of inclusivity. The Light422.10 profile is for instance contained in both the Main422.10
profile and the Light444.12 profile. The Main422.10 profile is again included in the Main444.12 profile,
etc. Some profiles are not included in other profiles, like the Main420.12 and the MLS.12 profiles.
The Light and Light-Subline profiles are independent subsets of the Main profile. They need lower
memory and logic resources, and allow for lower latency, at the expense of a lower compression
efficiency.
© ISO/IEC 2022 – All rights reserved

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