ISO/IEC 23090-18:2024/Amd 1:2024
(Amendment)Information technology — Coded representation of immersive media — Part 18: Carriage of geometry-based point cloud compression data — Amendment 1: Support for temporal scalability
Information technology — Coded representation of immersive media — Part 18: Carriage of geometry-based point cloud compression data — Amendment 1: Support for temporal scalability
Technologies de l'information — Représentation codée de média immersifs — Partie 18: Transport des données de compression des nuages de points basée sur la géométrie — Amendement 1: Prise en charge de l'échelonnabilité temporelle
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ISO/IEC 23090-18
First edition
Information technology — Coded
2024-01
representation of immersive media —
AMENDMENT 1
Part 18:
2024-09
Carriage of geometry-based point
cloud compression data
AMENDMENT 1: Support for temporal
scalability
Technologies de l'information — Représentation codée de média
immersifs —
Partie 18: Transport des données de compression des nuages de
points basée sur la géométrie
AMENDEMENT 1: Prise en charge de l'échelonnabilité temporelle
Reference number
ISO/IEC 23090-18:2024/Amd. 1:2024(en) © ISO/IEC 2024
ISO/IEC 23090-18:2024/Amd. 1:2024(en)
© ISO/IEC 2024
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ii
ISO/IEC 23090-18:2024/Amd. 1:2024(en)
Foreword
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This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information.
A list of all parts in the ISO/IEC 23090 series can be found on the ISO and IEC websites.
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© ISO/IEC 2024 – All rights reserved
iii
ISO/IEC 23090-18:2024/Amd. 1:2024(en)
Information technology — Coded representation of
immersive media —
Part 18:
Carriage of geometry-based point cloud compression data
AMENDMENT 1: Support for temporal scalability
Clause 3
Add the following terms:
3.12
temporal level track
volumetric visual track which carries a subset of point cloud frames in the G-PCC bitstream that constitute a
temporal sub-sequence of the actual G-PCC bitstream
3.13
temporal level tile track
volumetric visual track which carries one or more G-PCC tiles of a subset of point cloud frames in the G-PCC
bitstream that constitute a temporal sub-sequence of the actual G-PCC bitstream
7.2.1.2
Replace the content of the subclause with the following:
aligned(8) class GPCCDecoderConfigurationRecord {
unsigned int(8) configurationVersion = 1;
unsigned int(2) reserved = 0;
unsigned int(1) simple_profile_compliant;
unsigned int(1) dense_profile_compliant;
unsigned int(1) predictive_profile_compliant;
unsigned int(1) main_profile_compliant;
unsigned int(18) reserved_profile_18bits
unsigned int(8) level_idc;
unsigned int(7) num_setup_unit_arrays;
unsigned int(1) array_completeness;
for (i=0; i
unsigned int(8) setup_unit_type;
unsigned int(8) num_setup_units;
for (j=0; j
tlv_encapsulation setup_unit; //as defined in ISO/IEC 23090-9, Annex B
}
}
// additional fields
}
7.2.1.3
Replace
— numOfSetupUnits specifies the number of following setupUnit present in the decoder configuration record.
— setupUnit contains one data unit carrying one of SPS, GPS, and APS as defined in ISO/IEC 23090-9.
© ISO/IEC 2024 – All rights reserved
ISO/IEC 23090-18:2024/Amd. 1:2024(en)
with
— num_setup_unit_arrays indicates the number of arrays of setup units of the given type(s).
— array_completeness when equal to 1 indicates all parameter sets of all types are in the following array
and none are in the stream; when equal to 0 indicates that parameter set(s) of one or more types may
be in the stream; the default and permitted values are constrained by the sample entry type. When the
sample entry type of the track is 'gpe1' or 'gpc1', the value of array_completeness shall be equal to 1.
— setup_unit_type indicates the type of G-PCC setup units as defined in Annex B of ISO/IEC 23090-9.
— num_setup_units specifies the number of following setup_unit present in the decoder configuration record.
— setup_unit contains one data unit carrying one of SPS, GPS, and APS as defined in ISO/IEC 23090-9.
7.2.5, 7.26 and 7.2.7
Add the following subclauses after 7.2.4.
7.2.5 G-PCC parameter set sample group
7.2.5.1 Definition
'gpsg'
Group Types:
Container: Sample Group Description Box ('sgpd')
Mandatory: No
Quantity: Zero or more
A G-PCC parameter set sample group entry contains the parameter set information for samples that mapped
to it from SampleToGroupBox. Multiple SampleToGroupBox with grouping_type equal to ‘gpsg’ but with a
different grouping_type_parameter may be present. When multiple instances of the SampleToGroupBox with
grouping_type equal to 'gpsg' are present, the version of all the SampleToGroupBox boxes shall be set to 1.
A G-PCC parameter set sample group may be present in G-PCC tracks with track type 'gpcg’, 'gpeg’,
'gpcb’ and 'gpeb’. A G-PCC parameter set sample group shall not be present in G-PCC tracks with track
type 'gpc1’, 'gpe1’and 'gpt1’.
A SampleToGroupBox with grouping_type equal to ‘gpsg’ with a particular grouping_type_parameter
provides the mapping between samples with G-PCC parameter set sample group entries that contains all
parameter sets of that particular type.
NOTE When a particular G-PCC parameter set sample group entry is referred to / mapped to a sample in a
SampleToGroupBox with grouping_type equal to ‘gpsg’ with a particular grouping_type_parameter, the G-PCC
parameter set sample group entry contains all the parameter sets of that particular type for decoding the sample
while it can also contain other parameter sets as well.
Within a SampleToGroupBox with grouping_type equal to ‘gpsg’ with a particular grouping_type_parameter,
a sample shall be mapped to group_description_index value 0 when one of the following case is satisfied:
— The sample contains parameter set of that particular type.
— The sample does not contain the parameter set of that type but other parameter sets are present in the
sample entry.
For tracks with types 'gpeg’, 'gpcb’ and 'gpeb’, if only one SampleToGroupBox with grouping_type equal
to ‘gpsg’ is present in the track then grouping_type_parameter shall be set to zero. When a sample is
mapped to a G-PCC parameter set sample group entry in a SampleToGroupBox with grouping_type equal to
© ISO/IEC 2024 – All rights reserved
ISO/IEC 23090-18:2024/Amd. 1:2024(en)
‘gpsg’ and grouping_type_parameter equal to zero, the G-PCC parameter set sample group entry contains
the information to all the required parameter sets for the sample.
Annex L describes how the file player supports the random access.
7.2.5.2 Syntax
aligned(8) class GPCCParameterSetInfoEntry()
extends VolumetricVisualSampleGroupEntry ('gpsg') {
unsigned int(1) gpcc_unit_offset_flag;
unsigned int(7) num_parameter_sets_minus1;
for(int i = 0; i <= num_parameter_sets_minus1; i++) {
unsigned int(4) parameter_set_type;
unsigned int(4) parameter_set_id;
unsigned int(16)sample_offset;
if(gpcc_unit_offset_flag)
unsigned int(8) gpcc_unit_offset;
}
}
7.2.5.3 Semantics
gpcc_unit_offset_flag indicates whether the gpcc_unit offset information is present in the sample
description entry or not.
num_parameter_sets_minus1 plus one indicates the number of parameter sets described in the sample
description entry.
parameter_set_type indicates the type of the i-th parameter set as indicated in Table B.1 of ISO/IEC 23090-9.
parameter_set_id indicates the identifier of parameter set carried in the indicated sample. In case of
geometry parameter set, this value is equal to gps_geom_parameter_set_id present in the GPS. In case
of attribute parameter set, this field value is equal to aps_attr_parameter_set_id present in the APS. In
case of sequence parameter set, this field value is equal to sps_seq_parameter_set_id present in the SPS.
sample_offset specifies the sample offset from the immediately preceding sync sample where the indicated
parameter set is contained. The value of sample_offset shall be equal to or greater than 0.
NOTE When sample_offset is equal to 0, the sample that contains the parameter set is the immediately
preceding sync sample.
gpcc_unit_offset specifies that the i-th parameter set is the (gpcc_unit_offset + 1)-th GPCC unit in the
sample that contains the parameter set. The value of gpcc_unit_offset shall be equal to or greater than 0.
NOTE When gpcc_unit_offset is equal to 0, the parameter set is the 1st GPCC unit in the sample that
contains the parameter set.
7.2.6 Sub-frame timing sample group
7.2.6.1 Definition
This sample group provides sub-frame timing information which indicates a time offset to the composition
time of the G-PCC sample containing the sub-frame. When the track containing this sample group has no
CompositionOffsetBox, the composition time of the G-PCC sample corresponds to the decoding time of
this sample. The composition times for G-PCC sub-frames contained in a G-PCC sample is derived after the
composition time of the containing G-PCC sample is resolved.
— When the difference between sub-frame time offsets is constant (constant_time_offset_delta equals
1) for a group of G-PCC samples, the time offset of the i-th G-PCC sub-frame in a sample is equal to
subframe_time_offset_delta * i and the composition timestamp of the i-th G-PCC sub-frame in a sample
is computed as CTS[i] = CT + subframe_time_offset_delta * i, where CT is the composition time of
the sample containing the G-PCC sub-frame and i is varying from 0 to subframe_count – 1, included.
© ISO/IEC 2024 – All rights reserved
ISO/IEC 23090-18:2024/Amd. 1:2024(en)
— When the difference between sub-frame time offsets is not constant (constant_time_offset_delta
equals 0) for a group of G-PCC samples, the time offset of the i-th G-PCC sub-frame in a sample is equal
to subframe_time_offset[i] and the composition timestamp of the i-th G-PCC sub-frame in a sample is
computed as CTS[i] = CT + subframe_time_offset[i], where CT is the composition time of the sample
containing the sub-frame and i is varying from 0 to subframe_count – 1, included.
The loop on subframe_time_offset[i] is implicitly ordered in the order of sub-frames present in the samples
mapped to this entry with increasing frame index or frame number attribute values.
When a G-PCC bitstream contains sub-frames, i.e. frame number or frame index attribute, the following
constraints are applied:
— For single track encapsulation, when the G-PCC bitstream is carried using G-PCC tracks with ‘gpe1’ or
‘gpeg’ sample entry type, the subframe timing sample group may be present in the G-PCC track.
— For multi-track encapsulation, when the G-PCC bitstream is carried in multiple G-PCC tracks with 'gpc1'
or 'gpcg' sample entry type, the subframe timing sample group may be present only in the G-PCC
attribute track carrying the frame number or frame index attribute data units. The subframe timing
sample group shall not be present in G-PCC geometry track or G-PCC attribute track which does not carry
the frame number or frame index attribute data units.
— For encapsulation with G-PCC tile tracks, the sub-frame timing sample group may be present only in the
G-PCC tile track ('gpt1') carrying all components or in G-PCC attribute tile track carrying the frame
number or frame index attribute data units. The subframe timing sample group shall not be present in a
tile base track. The subframe timing sample group shall not be present in the following G-PCC tile tracks:
— G-PCC tile track carrying all components which are not comprised of the frame number or frame
index attribute data units;
— G-PCC geometry tile track;
— G-PCC attribute tile track which are not comprised of frame number or frame index attribute data units.
— The sub-frame timing sample group may be present in temporal level tracks or tempor
...
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