ISO/IEC 23000-19:2018/Amd 1:2018
(Amendment)Information technology — Multimedia application format (MPEG-A) — Part 19: Common media application format (CMAF) for segmented media — Amendment 1: SHVC media profile and additional audio media profiles
Information technology — Multimedia application format (MPEG-A) — Part 19: Common media application format (CMAF) for segmented media — Amendment 1: SHVC media profile and additional audio media profiles
Technologies de l'information — Format pour application multimédia (MPEG-A) — Partie 19: Format CMAF (Common Media Application Format) pour médias segmentés — Amendement 1: Profil média SHVC et profils médias audio supplémentaires
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INTERNATIONAL ISO/IEC
STANDARD 23000-19
First edition
2018-01
AMENDMENT 1
2018-10
Information technology — Multimedia
application format (MPEG-A) —
Part 19:
Common media application format
(CMAF) for segmented media
AMENDMENT 1: SHVC media profile and
additional audio media profiles
Technologies de l'information — Format pour application multimédia
(MPEG-A) —
Partie 19: Format CMAF (Common Media Application Format) pour
médias segmentés
AMENDEMENT 1: Profil média SHVC et profils médias audio
supplémentaires
Reference number
ISO/IEC 23000-19:2018/Amd.1:2018(E)
©
ISO/IEC 2018
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ISO/IEC 23000-19:2018/Amd.1:2018(E)
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ISO/IEC 23000-19:2018/Amd.1:2018(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
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ISO/IEC JTC 1.
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This document was prepared by Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information.
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ISO/IEC 23000-19:2018/Amd.1:2018(E)
Information technology — Multimedia application format
(MPEG-A) —
Part 19:
Common media application format (CMAF) for
segmented media
AMENDMENT 1: SHVC media profile and additional audio
media profiles
Clause 2
Add the following normative references:
1)
ISO/IEC 23008-3:— , Information technology — High efficiency coding and media delivery in
heterogeneous environments — Part 3: 3D audio
ISO/IEC 23091-3, Information technology — Coding-independent code points — Part 3: Audio
ISO/IEC 23003-4:2015, MPEG audio technologies — Part 4: Dynamic range control
Clause 3
Add the following terms and definitions to subclause 3.2:
3.2.10
audio programme
complete collection of all audio programme components and, if present, a set of accompanying presets
3.2.11
audio programme component
smallest addressable unit of an audio programme
Clause 5
Add the following new paragraphs at the end of Clause 5:
Annex H specifies the CMAF media profile for scalable HEVC (SHVC).
Annex I specifies the CMAF media profile for multichannel AAC.
Annex J specifies the CMAF media profile for MPEG-H audio.
1) Under preparation. Stage at the time of publication: ISO/FDIS 23008-3:2018.
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ISO/IEC 23000-19:2018/Amd.1:2018(E)
Subclause 9.1
Before the last paragraph in subclause 9.1, add a new paragraph:
An additional CMAF media profile for scalable HEVC (SHVC) is defined in Annex H.
Subclause 10.1
Replace the first sentence with:
This clause specifies CMAF audio tracks derived from the CMAF track format, with additional
constraints specific to CMAF audio tracks and audio CMAF media profiles.
Additional CMAF media profiles are defined in
— Annex I for multichannel AAC, and
— Annex J for MPEG-H 3D audio.
Annex G
Following Annex G, add new Annexes H, I and J:
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ISO/IEC 23000-19:2018/Amd.1:2018(E)
Annex H
(normative)
Scalable HEVC media profile and track format
H.1 Dependent CMAF tracks
Dependent CMAF tracks can only be processed with the availability of one or more CMAF tracks.
Specifically, CMAF fragments of dependent CMAF track can only be decoded and/or rendered if the
corresponding CMAF fragment of all of the CMAF tracks it depends on are available. CMAF tracks that
are not dependent CMAF tracks are regular CMAF tracks.
In a hypothetical CMAF receiver, the corresponding CMAF fragments of CMAF tracks depended on, are
expected to be available prior to the CMAF fragments of the dependent CMAF track.
A manifest offering CMAF presentations with dependent CMAF tracks is expected to provide signalling
of dependent and required CMAF tracks.
H.2 Scalable HEVC CMAF tracks
Scalable HEVC CMAF tracks shall conform to Clauses 7, 8, 9, and 12, and shall additionally conform to
the constraints specified in this Annex.
Each scalable HEVC CMAF track that does not contain VCL NAL units with nuh_layer_id and
TemporalID both equal to 0 is a dependent CMAF track and the constraints specified for dependent
CMAF tracks in Clause H.1 shall apply. It is expected that the manifest provides signalling to express the
dependency of a dependent CMAF track on another CMAF track, for example, using the @dependencyID
in a DASH MPD.
H.3 CMAF switching set constraints for scalable HEVC CMAF tracks and media
profiles
H.3.1 General
Subclause 9.2.3 applies, and additionally the following constraints apply:
— Each CMAF track with sample entry 'hev1' shall conform to the HEVC media profile and track
format as specified in Annex B.
— Each CMAF track containing a scalable HEVC bitstream or part thereof shall contain exactly one ISO
BMFF track.
— When multiple CMAF tracks are present for carrying a scalable HEVC bitstream, the corresponding
ISO BMFF tracks shall use distinct track IDs.
— CMAF switching sets containing a media profile listed in Clause H.6 with sample entry 'hev2' and
'lhe1' shall conform to single initialization CMAF switching set constraints.
Each coded video sequence in a scalable HEVC bitstream shall contain the necessary sequence
parameter set and picture parameter set NAL units to signal decoding parameters changes allowed
between CMAF tracks in the same switching set.
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ISO/IEC 23000-19:2018/Amd.1:2018(E)
H.3.2 Sample Description Box ('stsd')
Subclauses 9.2.4 and 9.3.2.2 shall apply with the following additional restrictions:
A decoder configuration record:
— shall signal other sequence parameter set and picture parameter set fields used by the video track
as specified in ISO/IEC 14496-15:2017, subclause 8.3.3.1,
— For a visual sample entry with codingname 'hev1', 'hev2', and 'lhe1' shall contain one or more
decoding parameter sets (containing VPS, SPS, and PPS NALs for HEVC video). Each video sample in
the CMAF track shall reference a parameter set in the sample entry.
— may contain additional SEI NAL units to signal colour encoding and rendering, such as mastering_
display_colour_volume, SEI payloadType=137 (ISO/IEC 23008-2), or alternative_
transfer_characteristics, SEI payloadType =147 (ISO/IEC 23008-2).
H.3.3 Track Header Box ('tkhd')
The requirements of 7.5.4 apply.
NOTE Normalized width and height can be derived from a sequence parameter set NAL in each segment
and coded video sequence for 'hev1', 'hev2', and 'lhe1' video samples. See subclause 9.2.3.3 for the storage and
semantics of video sequence parameter sets.
H.3.4 Access units
Clause 9.2.6 applies.
Access units shall conform to the requirements of a sample of the indicated description ('hev1', 'hev2',
or 'lhe1') as specified in ISO/IEC 14496-15.
CMAF fragments containing samples identified by the 'hev1', 'hev2', or 'lhe1' type shall contain
all SPS and PPS NALs referenced by a coded video sequence in the first access unit of that sequence,
immediately following its first access unit delimiter NAL (if any).
NOTE Access units of type 'hev1', 'hev2', and 'lhe1' can retain filler data (NAL units or SEI messages) and
SEI messages that would change hypothetical reference decoder bitstream conformance if such conformance is
necessary, such as the case where bitstreams are to be repackaged and conformance tested in MPEG-2 transport
streams.
H.3.5 Decoding of adaptively switched scalable HEVC CMAF tracks
Subclause 6.6.6 applies to switching between single-layer bitstreams, wherein a “conceptual” track is
generated by concatenating segments from different tracks among which the switching occurs. The
same applies for each of the multiple tracks carrying a scalable bitstream, with the only difference
being that, in this case multiple “conceptual” tracks are generated by concatenation of CMAF fragments.
Once the multiple “conceptual” tracks are generated, the process specified in ISO/IEC 14496-15:2017,
Clause 9 is applied to construct the bitstream to be decoded by the video decoder.
H.4 Sample and CMAF fragment constraints
H.4.1 Storage of scalable high efficiency video coding elementary streams
H.4.1.1 Conformance
Scalable high efficiency video coding (scalable HEVC) video tracks shall comply with ISO/IEC 14496-
15:2017, Clause 9, with the following constraints:
— Each track shall carry only one layer or only a subset of one layer.
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ISO/IEC 23000-19:2018/Amd.1:2018(E)
— Aggregators (as defined in ISO/IEC 14496-15:2017, Annex A) shall not be included in any track.
— The external base layer sample group shall not be included in any track.
The base layer (coded according to HEVC specification) shall be stored as described in subclause B.3.1.
H.4.1.2 Visual sample entry
The base track’s syntax and values for a visual sample entry shall conform to sample entry 'hev1' as
defined in ISO/IEC 14496-15.
— For each track that carries a subset of the base layer where the subset contains VCL NAL units with
TemporalId greater than 0 only, the sample entry type shall be 'hev2'.
— For each track that carries a layer for which the VCL NAL units have nuh_layer_id greater than 0 or
a subset of such a layer, the sample entry type shall be 'lhe1'.
H.4.1.3 HEVCDecoderConfigurationRecord and LHEVCDecoderConfigurationRecord
The HEVCDecoderConfigurationRecord and the HEVC compatible base layer shall conform to
subclause B.3.1.3.
The LHEVCDEcoderConfigurationRecord and the enhancement layers shall conform to subclause
B.3.1.3. inclusion, use and passing of SEI messages.
H.4.2 Constraints on scalable HEVC elementary streams
H.4.2.1 General
The following constraints apply to all CMAF scalable HEVC elementary streams. See Clause H.6 for
media profile constraints on tier, profile, level, and frame rates.
H.4.2.2 General constraints
— The bitstream shall contain at most two layers, a base layer and possibly an enhancement layer.
— The base layer shall conform to HEVC Main 10 profile and main tier.
— The enhancement layer, when present, shall conform to HEVC scalable Main 10 profile and main tier.
— The spatial resolution of the enhancement layer shall be equal to X times that of the base layer both
horizontally and vertically. The value of X shall be 1.5, 2, or 3.
— Each layer shall contain at most two sub-layers, with TemporalId equal to 0 and 1 when there are
two sub-layers, and the value of sps_max_sub_layers_minus1 of each SPS shall be set equal to
0 or 1. If there is only one sub-layer, the TemporalId shall be 0.
— The value of sub_layer_level_present_flag[ 0 ] shall be equal to 1. This constraint requires
the signalling of the level of the sub-layer representation with TemporalId equal to 0.
H.4.2.3 Picture rate related constraints
— An enhancement layer shall only be present, if the base layer has constant picture rate.
— The enhancement layer, if present, shall have the same number of sub-layers as the base layer.
— When a layer has two sub-layers, the sub-layer representation with TemporalId equal to 0 shall
have a constant picture rate (as indicated by the presence of elemental_duration_in_tc_
minus1[ 0 ]), and the picture rate shall be exactly half of that of the entire layer’s picture rate
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ISO/IEC 23000-19:2018/Amd.1:2018(E)
(i.e., elemental_duration_in_tc_minus1[ 0 ] is equal to 2 * elemental_duration_
in_tc_minus1[ 1 ]).
— The enhancement layer, when present, shall have the same picture rate as the base layer.
— The vps_vui_present_flag in each VPS shall be set equal to 1, pic_rate_present_vps_
flag shall be set equal to 1, pic_rate_present_flag[ i ][ j ] shall be set equal to 1 and
constant_pic_rate_idc[ i ][ j ] shall be set equal to 1 for all i, for all j.
— The vui_parameters_present_flag in each SPS shall be set equal to 1, vui_timing_info_
present_flag in each SPS shall be set equal to 1, vui_hrd_parameters_present_flag in each
SPS shall be set equal to 1, and fixed_pic_rate_general_flag[ i ] shall be set equal to 1 or
fixed_pic_rate_within_cvs_flag[ i ] shall be set equal to 1 for all values of i in the range
of 0 to maxNumSubLayersMinus1, inclusive.
— If vps_num_hrd_parameters is greater than 0, the following shall apply:
— For each hrd_parameters() syntax structure in the VPS: fixed_pic_rate_general_
flag[ i ] shall be set equal to 1 or fixed_pic_rate_within_cvs_flag[ i ] shall be set
equal to 1 for all values of i in the range 0 to maxNumSubLayersMinus1, inclusive.
— For each value of i in the range 0 to maxNumSubLayersMinus1, inclusive, the value of the
syntax element elemental_duration_in_tc_minus1[ i ] in the hrd_parameters()
syntax structure applicable to the enhancement layer shall be equal to the value of the syntax
element elemental_duration_in_tc_minus1[ i ] in the hrd_parameters() syntax
structure applicable to the base layer.
NOTE This profile is restricted to equal picture rates on both layers. Implementations can, however,
be capable of switching between different picture rates.
H.4.2.4 Picture type
All pictures shall be encoded as coded frames, and shall not be encoded as coded fields.
H.4.2.5 Video parameter sets (VPS)
H.4.2.5.1 VPS fields
Each scalable HEVC video sample in the CMAF track shall reference the VPS in the CMAF header sample
entry according to ISO/IEC 14496-15. VPS shall not change within CMAF tracks or between CMAF
tracks in a switching set. A CMAF scalable HEVC track shall conform to ISO/IEC 23008-2:2017, Annexes
F and H with the following additional constraints:
— The following fields shall have values set as follows for each profile_tier_level() structure in VPS:
— general_progressive_source_flag shall be set to 1.
— general_frame_only_constraint_flag shall be set to 1.
— general_interlaced_source_flag shall be set to 0.
— general_non_packed_constraint_flag shall be set to 0.
— vps_extension_flag shall be set to 1.
— vps_vui_present_flag shall be set to 1.
— The condition of the following fields for each profile_tier_level() structure in VPS shall not change
throughout an scalable HEVC elementary stream:
— general_profile_space
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ISO/IEC 23000-19:2018/Amd.1:2018(E)
— general_profile_idc
— general_tier_flag
— general_level_idc
— The value of vps_max_layers_minus1 of each VPS shall be set equal to 1.
— The value of sub_layer_level_present_flag[ 0 ] shall be equal to 1 only when the value of
sub_layer_level_idc[ 0 ] is different than the value of general_level_idc.
H.4.2.5.2 VPS visual usability information (VPS VUI) fields
VPS VUI parameters that occur within a CMAF scalable HEVC track shall conform to ISO/IEC 23008-
2:2017, Annexes F and H with the following additional constraints:
— pic_rate_present_vps_flag shall be set equal to 1.
— pic_rate_present_flag[ i ][ j ] shall be set equal to 1.
— constant_pic_rate_idc[ i ][ j ] shall be set equal to 1 for all i, for j equal to
MaxSubLayersInLayerSetMinus1[ i ].
The values of the following fields in each video_signal_info() in VPS VUI shall not change
throughout a CMAF track and switching set:
— vps_video_format
— video_full_range_vps_flag
— colour_primaries_vps
— transfer_characteristics_vps
— matrix_coeffs_vps
H.4.2.6 Sequence parameter sets (SPS)
H.4.2.6.1 SPS fields
Sequence parameter set NAL units that occur within a CMAF scalable HEVC track shall conform to ISO/
IEC 23008-2:2017, Annexes F and H with the following additional constraints:
— The following fields shall have pre-determined values as follows:
— general_progressive_source_flag shall be set to 1.
— general_frame_only_constraint_flag shall be set to 1.
— general_interlaced_source_flag shall be set to 0.
— general_non_packed_constraint_flag shall be set to 0.
— vui_parameters_present_flag shall be set to 1.
— vui_timing_info_present_flag shall be set to 1, vui_hrd_parameters_present_flag
in shall be set to 1, and fixed_pic_rate_general_flag[ i ] shall be set equal to 1 or fixed_
pic_rate_within_cvs_flag [ maxNumSubLayersMinus1 ] shall be set equal to 1.
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ISO/IEC 23000-19:2018/Amd.1:2018(E)
H.4.2.6.2 Visual usability information (VUI) fields
VUI parameters that occur within a CMAF scalable HEVC track shall conform to ISO/IEC 23008-2:2017,
Annexes F and H with the following additional constraints:
— The following fields shall have pre-determined values as defined:
— video_full_range_flag shall be set to 0.
Specification for:
colour_description_present_flag, overscan_info_present_flag, low_delay_hrd_flag,
colour_description_present_flag, colour_primaries, transfer_characteristics,
matrix_coeffs, vui_time_scal
...
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