ISO/IEC 14496-15:2022/Amd 1:2023
(Amendment)Information technology — Coding of audio-visual objects — Part 15: Carriage of network abstraction layer (NAL) unit structured video in the ISO base media file format — Amendment 1: Support for LCEVC
Information technology — Coding of audio-visual objects — Part 15: Carriage of network abstraction layer (NAL) unit structured video in the ISO base media file format — Amendment 1: Support for LCEVC
Technologies de l'information — Codage des objets audiovisuels — Partie 15: Transport de vidéo structurée en unités NAL sur la couche réseau au format ISO de base pour les fichiers médias — Amendement 1: Support pour LCEVC
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INTERNATIONAL ISO/IEC
STANDARD 14496-15
Sixth edition
2022-10
AMENDMENT 1
2023-10
Information technology — Coding of
audio-visual objects —
Part 15:
Carriage of network abstraction layer
(NAL) unit structured video in the ISO
base media file format
AMENDMENT 1: Support for LCEVC
Technologies de l'information — Codage des objets audiovisuels —
Partie 15: Transport de vidéo structurée en unités NAL sur la couche
réseau au format ISO de base pour les fichiers médias
AMENDEMENT 1: Support pour LCEVC
Reference number
ISO/IEC 14496-15:2022/Amd. 1:2023(E)
© ISO/IEC 2023
ISO/IEC 14496-15:2022/Amd. 1:2023(E)
© ISO/IEC 2023
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© ISO/IEC 2023 – All rights reserved
ISO/IEC 14496-15:2022/Amd. 1:2023(E)
Foreword
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accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives or
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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 14496 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
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© ISO/IEC 2023 – All rights reserved
ISO/IEC 14496-15:2022/Amd. 1:2023(E)
Information technology — Coding of audio-visual
objects —
Part 15:
Carriage of network abstraction layer (NAL) unit
structured video in the ISO base media file format
AMENDMENT 1: Support for LCEVC
Normative references
Add the following reference:
ISO/IEC 23094-2:2021, Information technology – General Video Coding – Part 2: Low Complexity
Enhancement Video Coding
3.1 Terms and definitions
Add the following terms and definitions:
3.1.67
parameter sets for LCEVC
sequence_configuration, global_configuration, or additional_info
Note 1 to entry: As defined in ISO/IEC 23094-2:2021, 7.3.4, 7.3.5, 7.3.10.
3.1.68
picture dimensions for LCEVC
width and height of the decoded picture as specified by the referenced global_configuration
Note 1 to entry: As defined in ISO/IEC 23094-2:2021, 7.3.5.
3.2 Abbreviated terms
Add the following abbreviated terms:
LCEVC Low Complexity Enhancement Video Coding [ISO/IEC 23094-2]
GC Global Configuration for LCEVC [ISO/IEC 23094-2]
SC Sequence Configuration for LCEVC [ISO/IEC 23094-2]
AI Additional Information for LCEVC [ISO/IEC 23094-2]
© ISO/IEC 2023 – All rights reserved
ISO/IEC 14496-15:2022/Amd. 1:2023(E)
4.2.3.3
Replace
“The syntax of a NAL unit is defined in the appropriate specification (e.g. ISO/IEC 14496-10) and
includes both the one byte NAL header and the variable length encapsulated byte stream payload.”
with
“NALUnit contains a single NAL unit. The syntax of a NAL unit is defined in the appropriate specification
(e.g. ISO/IEC 14496-10) and includes both the NAL unit header and the variable length NAL unit
payload.”
5.4.2.1.1
Replace:
“The sample entry name 'avc1' or 'avc3' may only be used when the stream to which this sample entry
applies is a compliant and AVC stream as viewed by an AVC decoder operating under the configuration
(including profile and level) given in the AVCConfigurationBox. The file format specific structures that
resemble NAL units (see Annex A) may be present but shall not be used to access the AVC base data; that
is, the AVC data shall not be contained in Aggregators (though they may be included within the bytes
referenced by the additional_bytes field) nor referenced by Extractors.”
with:
“The sample entry name 'avc1' or 'avc3' may only be used when the stream to which this sample entry
applies is a compliant and AVC stream as viewed by an AVC decoder operating under the configuration
(including profile and level) given in the AVCConfigurationBox. Extractor and aggregator NAL-unit-like
structures (see Annex A) shall not be present.”
6.5.3.1.1
Replace “Extractors or aggregators may be used for SVC VCL NAL units in 'avc1', 'avc2', 'avc3', 'avc4',
'svc1' or 'svc2' tracks” with "Extractors or aggregators may be used for SVC VCL NAL units 'avc2', 'avc4',
'svc1' or 'svc2' tracks.”
11.2.4.1.2
Replace "ptl_multi_layer_enabled_flag" with "ptl_multilayer_enabled_flag".
11.2.4.1.3
Replace "ptl_multi_layer_enabled_flag" with "ptl_multilayer_enabled_flag".
12.5.4.2
Replace subclause 12.5.4.2 with the following:
12.5.4.2 Sample entry for EVC slice base track
12.5.4.2.1 Definition
© ISO/IEC 2023 – All rights reserved
ISO/IEC 14496-15:2022/Amd. 1:2023(E)
'evm1'
Sample Entry Type:
Container: Sample Table Box ('stbl')
Mandatory: An 'evm1' sample entry is mandatory for EVC slice base track
Quantity: One or more sample entries may be present
An EVC visual sample entry shall contain an EVC Configuration Box as defined in the subclause 12.4.1.1
when a track is an EVC slice base track. This includes an EVCDecoderConfigurationRecord defined in the
subclause 12.3.3.
An optional BitRateBox may be present in the EVC visual sample entry to signal the bit rate information
of the EVC slice data in this track.
Multiple sample entries may be used, as permitted by the ISO Base Media File Format specification, to
indicate sections of video that use different configurations or parameter sets.
12.5.4.2.2 Syntax
class EVCSampleEntry() extends VisualSampleEntry('evm1'){
EVCConfigurationBox config;
MPEG4ExtensionDescriptorsBox(); // optional
}
12.5.4.2.3 Semantics
Compressorname in the base class VisualSampleEntry indicates the name of the compressor used
with the value "\012EVC Coding" being recommended (\012 is 10, the length of the string in
bytes).
EVCDecoderConfigurationRecord is defined in subclause 12.3.3.
Clause 13
Add the following clause after Clause 12, before Annex A:
13 LCEVC elementary streams and sample definitions
13.1 Overview
The Low Complexity Enhancement Video Coding (LCEVC) standard, specified in ISO/IEC 23094-2:2021,
is a low complexity solution to apply enhancement to existing video coding bitstreams generated using
other video coding systems (e.g. AVC, HEVC, EVC, VVC).
Since the LCEVC elementary streams carry enhancement to a "base" codec such as the ones listed above,
the LCEVC elementary stream in its own track makes reference to a "base" codec elementary stream in
a separate track, so that the LCEVC stream can be decoded in conjunction with the "base" stream, while
the "base" stream can be decoded independently of the LCEVC stream.
This clause defines the carriage of LCEVC elementary streams in the ISO base media file format as
defined in this document.
The Elementary Stream Structure is provided in subclause 13.2.
The Sample and Configuration Definitions are provided in subclause 13.3.
© ISO/IEC 2023 – All rights reserved
ISO/IEC 14496-15:2022/Amd. 1:2023(E)
Deviations from ISO base media file format are provided in subclause 13.4.
Internet media applications require defined values for the codecs parameter specified in IETF RFC
6381 for ISOBMFF Media tracks. The 'codecs' parameter string for the LCEVC codec is defined in
subclause E.10.
13.2 Elementary stream structure
LCEVC elementary streams are structured as NAL units and their storage in the ISO Base Media File
Format follows principles similar to other NAL structured video formats.
The storage of LCEVC elementary streams is subdivided into two parts: static information that is
globally used in the elementary stream and dynamic information that may vary per sample.
The sequence_configuration (SC), global_configuration (GC), and additional_info (AI), are considered to
be part of the information that rarely changes and is considered to be static.
In case these parameter sets change in the elementary stream, a sample grouping is defined that
indicates at which sample the parameter sets change.
13.3 Sample and configuration definitions
13.3.1 Overview
An LCEVC Sample follows the same structure of the “General Definitions” as defined in subclause 4.2.3
of this document.
The only additional constraint is that the DecoderConfigurationRecord shall follow the syntax and
semantics specific for LCEVC, i.e. LCEVCDecoderConfigurationRecord.
An LCEVC Sample contains an access unit as defined in ISO/IEC 23094-2:2021, 3.1.
13.3.2 Canonical order
The canonical stream format is an LCEVC elementary stream that satisfies the general conditions in
subclauses 6.1 and 7.3 of ISO/IEC 23094-2:2021.
The following additional constraints apply:
— SC, GC, AI: sequence_configuration, global_configuration, and additional_info to be used in a picture
must be sent prior to the sample containing that picture or in the sample for that picture. At least
the one sequence_configuration and one global_configuration must be stored in the sample entry
of the track that contains the LCEVC elementary stream. The sequence_configuration and global_
configuration, when carried in a sample for a specific picture, shall be present at least in each sync
sample.
— SEI messages: SEI messages of declarative nature may be stored in the sample entry; there is no
prescription about removing such SEI messages from the samples.
— Filler data. Video data is naturally represented as variable bit rate in the file format and should be
filled for transmission if needed.
13.3.3 Decoder Configuration Information
13.3.3.1 Definition
This subclause specifies the Decoder Configuration Information for ISO/IEC 23094-2 video content.
This record contains a version field. This version of the specification defines version 1 of this record.
Incompatible changes to the record will be indicated by a change of version number. Readers shall not
attempt to decode this record or the streams to which it applies if the version number is unrecognised.
© ISO/IEC 2023 – All rights reserved
ISO/IEC 14496-15:2022/Amd. 1:2023(E)
Compatible extensions to this record will extend it and will not change the configuration version
code. Readers should be prepared to ignore unrecognised data beyond the definition of the data they
understand.
The values for LCEVCProfileIndication, LCEVCLevelIndication, chroma_format_idc, pic_width_in_
luma_samples, pic_height_in_luma_samples, bit_depth_luma_minus8, and bit_depth_chroma_minus8
shall be valid for all parameter sets (SC, GC, AI) that are activated when the stream described by this
record is decoded (referred to as "all the parameter sets" in the reminder of this clause).
Specifically, the following restrictions apply:
— The profile indication LCEVCProfileIndication shall indicate a profile to which the stream
associated with this configuration record conforms.
— The level indication LCEVCLevelIndication shall indicate a level of capability equal to or greater
than the highest level indicated in all the parameter sets of this configuration record.
— The pic_width_in_luma_samples and pic_height_in_luma_samples shall contain the highest values
of all parameter sets of this configuration record.
— The value of chroma_format_idc in all the parameter sets shall be identical.
— The value of bit_depth_luma_minus8 in all the parameter sets shall be identical.
— The value of bit_depth_chroma_minus8 in all the parameter sets shall be identical.
Explicit indication is provided in the LCEVC Decoder Configuration Information about the chroma
format and bit depth used by the LCEVC video elementary stream. Each instance of such information
shall be identical in all parameter sets, if present, in a single LCEVC configuration record. If two
sequences differ in any instance of such information, two different LCEVC sample entries shall be used.
The length field is used in each sample to indicate the length of its contained NAL units as well as the
parameter sets,
...
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