rfc9328.original   rfc9328.txt 
avtcore S. Zhao Internet Engineering Task Force (IETF) S. Zhao
Internet-Draft Intel Request for Comments: 9328 Intel
Intended status: Standards Track S. Wenger Category: Standards Track S. Wenger
Expires: 2 February 2023 Tencent ISSN: 2070-1721 Tencent
Y. Sanchez Y. Sanchez
Fraunhofer HHI Fraunhofer HHI
Y.-K. Wang Y.-K. Wang
Bytedance Inc. Bytedance Inc.
M. M Hannuksela M. M Hannuksela
Nokia Technologies Nokia Technologies
1 August 2022 December 2022
RTP Payload Format for Versatile Video Coding (VVC) RTP Payload Format for Versatile Video Coding (VVC)
draft-ietf-avtcore-rtp-vvc-18
Abstract Abstract
This memo describes an RTP payload format for the video coding This memo describes an RTP payload format for the Versatile Video
standard ITU-T Recommendation H.266 and ISO/IEC International Coding (VVC) specification, which was published as both ITU-T
Standard 23090-3, both also known as Versatile Video Coding (VVC) and Recommendation H.266 and ISO/IEC International Standard 23090-3. VVC
developed by the Joint Video Experts Team (JVET). The RTP payload was developed by the Joint Video Experts Team (JVET). The RTP
format allows for packetization of one or more Network Abstraction payload format allows for packetization of one or more Network
Layer (NAL) units in each RTP packet payload as well as fragmentation Abstraction Layer (NAL) units in each RTP packet payload, as well as
of a NAL unit into multiple RTP packets. The payload format has wide fragmentation of a NAL unit into multiple RTP packets. The payload
applicability in videoconferencing, Internet video streaming, and format has wide applicability in videoconferencing, Internet video
high-bitrate entertainment-quality video, among other applications. streaming, and high-bitrate entertainment-quality video, among other
applications.
Status of This Memo Status of This Memo
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction
1.1. Overview of the VVC Codec . . . . . . . . . . . . . . . . 3 1.1. Overview of the VVC Codec
1.1.1. Coding-Tool Features (informative) . . . . . . . . . 4 1.1.1. Coding-Tool Features (Informative)
1.1.2. Systems and Transport Interfaces (informative) . . . 6 1.1.2. Systems and Transport Interfaces (Informative)
1.1.3. High-Level Picture Partitioning (informative) . . . . 11 1.1.3. High-Level Picture Partitioning (Informative)
1.1.4. NAL Unit Header . . . . . . . . . . . . . . . . . . . 13 1.1.4. NAL Unit Header
1.2. Overview of the Payload Format . . . . . . . . . . . . . 15 1.2. Overview of the Payload Format
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 15 2. Conventions
3. Definitions and Abbreviations . . . . . . . . . . . . . . . . 15 3. Definitions and Abbreviations
3.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 15 3.1. Definitions
3.1.1. Definitions from the VVC Specification . . . . . . . 16 3.1.1. Definitions from the VVC Specification
3.1.2. Definitions Specific to This Memo . . . . . . . . . . 19 3.1.2. Definitions Specific to This Memo
3.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 19 3.2. Abbreviations
4. RTP Payload Format . . . . . . . . . . . . . . . . . . . . . 20 4. RTP Payload Format
4.1. RTP Header Usage . . . . . . . . . . . . . . . . . . . . 21 4.1. RTP Header Usage
4.2. Payload Header Usage . . . . . . . . . . . . . . . . . . 22 4.2. Payload Header Usage
4.3. Payload Structures . . . . . . . . . . . . . . . . . . . 22 4.3. Payload Structures
4.3.1. Single NAL Unit Packets . . . . . . . . . . . . . . . 23 4.3.1. Single NAL Unit Packets
4.3.2. Aggregation Packets (APs) . . . . . . . . . . . . . . 23 4.3.2. Aggregation Packets (APs)
4.3.3. Fragmentation Units . . . . . . . . . . . . . . . . . 28 4.3.3. Fragmentation Units
4.4. Decoding Order Number . . . . . . . . . . . . . . . . . . 31 4.4. Decoding Order Number
5. Packetization Rules . . . . . . . . . . . . . . . . . . . . . 33 5. Packetization Rules
6. De-packetization Process . . . . . . . . . . . . . . . . . . 34 6. De-packetization Process
7. Payload Format Parameters . . . . . . . . . . . . . . . . . . 36 7. Payload Format Parameters
7.1. Media Type Registration . . . . . . . . . . . . . . . . . 36 7.1. Media Type Registration
7.2. Optional Parameters Definition . . . . . . . . . . . . . 37 7.2. Optional Parameters Definition
7.3. SDP Parameters . . . . . . . . . . . . . . . . . . . . . 47 7.3. SDP Parameters
7.3.1. Mapping of Payload Type Parameters to SDP . . . . . . 48 7.3.1. Mapping of Payload Type Parameters to SDP
7.3.2. Usage with SDP Offer/Answer Model . . . . . . . . . . 50 7.3.2. Usage with SDP Offer/Answer Model
7.3.3. Multicast . . . . . . . . . . . . . . . . . . . . . . 59 7.3.3. Multicast
7.3.4. Usage in Declarative Session Descriptions . . . . . . 59 7.3.4. Usage in Declarative Session Descriptions
7.3.5. Considerations for Parameter Sets . . . . . . . . . . 61 7.3.5. Considerations for Parameter Sets
8. Use with Feedback Messages
8. Use with Feedback Messages . . . . . . . . . . . . . . . . . 61 8.1. Picture Loss Indication (PLI)
8.1. Picture Loss Indication (PLI) . . . . . . . . . . . . . . 61 8.2. Full Intra Request (FIR)
8.2. Full Intra Request (FIR) . . . . . . . . . . . . . . . . 61 9. Security Considerations
9. Security Considerations . . . . . . . . . . . . . . . . . . . 62 10. Congestion Control
10. Congestion Control . . . . . . . . . . . . . . . . . . . . . 63 11. IANA Considerations
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 64 12. References
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 64 12.1. Normative References
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 64 12.2. Informative References
13.1. Normative References . . . . . . . . . . . . . . . . . . 64 Acknowledgements
13.2. Informative References . . . . . . . . . . . . . . . . . 66 Authors' Addresses
Appendix A. Change History . . . . . . . . . . . . . . . . . . . 68
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 68
1. Introduction 1. Introduction
The Versatile Video Coding specification was formally published as The Versatile Video Coding specification was formally published as
both ITU-T Recommendation H.266 [VVC] and ISO/IEC International both ITU-T Recommendation H.266 [VVC] and ISO/IEC International
Standard 23090-3 [ISO23090-3]. VVC is reported to provide Standard 23090-3 [ISO23090-3]. VVC is reported to provide
significant coding efficiency gains over High Efficiency Video Coding significant coding efficiency gains over High Efficiency Video Coding
[HEVC], also known as H.265, and other earlier video codecs. [HEVC], also known as H.265, and other earlier video codecs.
This memo specifies an RTP payload format for VVC. It shares its This memo specifies an RTP payload format for VVC. It shares its
basic design with the NAL (Network Abstraction Layer) unit based RTP basic design with the NAL-unit-based RTP payload formats of Advanced
payload formats of AVC Video Coding [RFC6184], Scalable Video Coding Video Coding (AVC) [RFC6184], Scalable Video Coding (SVC) [RFC6190],
(SVC) [RFC6190], High Efficiency Video Coding (HEVC) [RFC7798] and and High Efficiency Video Coding (HEVC) [RFC7798], as well as their
their respective predecessors. With respect to design philosophy, respective predecessors. With respect to design philosophy,
security, congestion control, and overall implementation complexity, security, congestion control, and overall implementation complexity,
it has similar properties to those earlier payload format it has similar properties to those earlier payload format
specifications. This is a conscious choice, as at least RFC 6184 is specifications. This is a conscious choice, as at least [RFC6184] is
widely deployed and generally known in the relevant implementer widely deployed and generally known in the relevant implementer
communities. Certain scalability-related mechanisms known from communities. Certain scalability-related mechanisms known from
[RFC6190] were incorporated into this document, as VVC version 1 [RFC6190] were incorporated into this document, as VVC version 1
supports temporal, spatial, and signal-to-noise ratio (SNR) supports temporal, spatial, and signal-to-noise ratio (SNR)
scalability. scalability.
1.1. Overview of the VVC Codec 1.1. Overview of the VVC Codec
VVC and HEVC share a similar hybrid video codec design. In this VVC and HEVC share a similar hybrid video codec design. In this
memo, we provide a very brief overview of those features of VVC that memo, we provide a very brief overview of those features of VVC that
are, in some form, addressed by the payload format specified herein. are, in some form, addressed by the payload format specified herein.
Implementers have to read, understand, and apply the ITU-T/ISO/IEC Implementers have to read, understand, and apply the ITU-T/ISO/IEC
specifications pertaining to VVC to arrive at interoperable, well- specifications pertaining to VVC to arrive at interoperable, well-
performing implementations. performing implementations.
Conceptually, both VVC and HEVC include a Video Coding Layer (VCL), Conceptually, both VVC and HEVC include a Video Coding Layer (VCL),
which is often used to refer to the coding-tool features, and a NAL, which is often used to refer to the coding-tool features, and a NAL,
which is often used to refer to the systems and transport interface which is often used to refer to the systems and transport interface
aspects of the codecs. aspects of the codecs.
1.1.1. Coding-Tool Features (informative) 1.1.1. Coding-Tool Features (Informative)
Coding tool features are described below with occasional reference to Coding-tool features are described below with occasional reference to
the coding tool set of HEVC, which is well known in the community. the coding-tool set of HEVC, which is well known in the community.
Similar to earlier hybrid-video-coding-based standards, including Similar to earlier hybrid-video-coding-based standards, including
HEVC, the following basic video coding design is employed by VVC. A HEVC, the following basic video coding design is employed by VVC. A
prediction signal is first formed by either intra- or motion- prediction signal is first formed by either intra- or motion-
compensated prediction, and the residual (the difference between the compensated prediction, and the residual (the difference between the
original and the prediction) is then coded. The gains in coding original and the prediction) is then coded. The gains in coding
efficiency are achieved by redesigning and improving almost all parts efficiency are achieved by redesigning and improving almost all parts
of the codec over earlier designs. In addition, VVC includes several of the codec over earlier designs. In addition, VVC includes several
tools to make the implementation on parallel architectures easier. tools to make the implementation on parallel architectures easier.
Finally, VVC includes temporal, spatial, and SNR scalability as well Finally, VVC includes temporal, spatial, and SNR scalability, as well
as multiview coding support. as multiview coding support.
Coding blocks and transform structure Coding blocks and transform structure
Among major coding-tool differences between HEVC and VVC, one of
Among major coding-tool differences between HEVC and VVC, one of the the important improvements is the more flexible coding tree
important improvements is the more flexible coding tree structure in structure in VVC, i.e., multi-type tree. In addition to quadtree,
VVC, i.e., multi-type tree. In addition to quadtree, binary and binary and ternary trees are also supported, which contributes
ternary trees are also supported, which contributes significant significant improvement in coding efficiency. Moreover, the
improvement in coding efficiency. Moreover, the maximum size of a maximum size of a coding tree unit (CTU) is increased from 64x64
coding tree unit (CTU) is increased from 64x64 to 128x128. To to 128x128. To improve the coding efficiency of chroma signal,
improve the coding efficiency of chroma signal, luma chroma separated luma-chroma-separated trees at CTU level may be employed for intra
trees at CTU level may be employed for intra-slices. The square slices. The square transforms in HEVC are extended to non-square
transforms in HEVC are extended to non-square transforms for transforms for rectangular blocks resulting from binary and
rectangular blocks resulting from binary and ternary tree splits. ternary tree splits. Besides, VVC supports multiple transform
Besides, VVC supports multiple transform sets (MTS), including DCT-2, sets (MTSs), including DCT-2, DST-7, and DCT-8, as well as the
DST-7, and DCT-8 as well as the non-separable secondary transform. non-separable secondary transform. The transforms used in VVC can
The transforms used in VVC can have different sizes with support for have different sizes with support for larger transform sizes. For
larger transform sizes. For DCT-2, the transform sizes range from DCT-2, the transform sizes range from 2x2 to 64x64, and for DST-7
2x2 to 64x64, and for DST-7 and DCT-8, the transform sizes range from and DCT-8, the transform sizes range from 4x4 to 32x32. In
4x4 to 32x32. In addition, VVC also support sub-block transform for addition, VVC also support sub-block transform for both intra- and
both intra and inter coded blocks. For intra coded blocks, intra inter-coded blocks. For intra-coded blocks, intra sub-
sub-partitioning (ISP) may be used to allow sub-block based intra partitioning (ISP) may be used to allow sub-block-based intra
prediction and transform. For inter blocks, sub-block transform may prediction and transform. For inter blocks, sub-block transform
be used assuming that only a part of an inter-block has non-zero may be used assuming that only a part of an inter block has non-
transform coefficients. zero transform coefficients.
Entropy coding Entropy coding
Similar to HEVC, VVC uses a single entropy-coding engine, which is
Similar to HEVC, VVC uses a single entropy-coding engine, which is based on context adaptive binary arithmetic coding [CABAC] but
based on context adaptive binary arithmetic coding [CABAC], but with with the support of multi-window sizes. The window sizes can be
the support of multi-window sizes. The window sizes can be initialized differently for different context models. Due to such
initialized differently for different context models. Due to such a a design, it has more efficient adaptation speed and better coding
design, it has more efficient adaptation speed and better coding efficiency. A joint chroma residual coding scheme is applied to
efficiency. A joint chroma residual coding scheme is applied to further exploit the correlation between the residuals of two color
further exploit the correlation between the residuals of two color components. In VVC, different residual coding schemes are applied
components. In VVC, different residual coding schemes are applied for regular transform coefficients and residual samples generated
for regular transform coefficients and residual samples generated using transform-skip mode.
using transform-skip mode.
In-loop filtering In-loop filtering
VVC has more feature support in loop filters than HEVC. The
VVC has more feature support in loop filters than HEVC. The deblocking filter in VVC is similar to HEVC but operates at a
deblocking filter in VVC is similar to HEVC but operates at a smaller smaller grid. After deblocking and sample adaptive offset (SAO),
grid. After deblocking and sample adaptive offset (SAO), an adaptive an adaptive loop filter (ALF) may be used. As a Wiener filter,
loop filter (ALF) may be used. As a Wiener filter, ALF reduces ALF reduces distortion of decoded pictures. Besides, VVC
distortion of decoded pictures. Besides, VVC introduces a new module introduces a new module called luma mapping with chroma scaling to
called luma mapping with chroma scaling to fully utilize the dynamic fully utilize the dynamic range of signal so that rate-distortion
range of signal so that rate-distortion performance of both Standard performance of both Standard Dynamic Range (SDR) and High Dynamic
Dynamic Range (SDR) and High Dynamic Range (HDR) content is improved. Range (HDR) content is improved.
Motion prediction and coding Motion prediction and coding
Compared to HEVC, VVC introduces several improvements in this
area. First, there is the adaptive motion vector resolution
(AMVR), which can save bit cost for motion vectors by adaptively
signaling motion vector resolution. Then, the affine motion
compensation is included to capture complicated motion-like
zooming and rotation. Meanwhile, prediction refinement with the
optical flow (PROF) with affine mode is further deployed to mimic
affine motion at the pixel level. Thirdly, the decoder-side
motion vector refinement (DMVR) is a method to derive the motion
vector at the decoder side based on block matching so that fewer
bits may be spent on motion vectors. Bidirectional optical flow
(BDOF) is a similar method to PROF. BDOF adds a sample-wise
offset at the 4x4 sub-block level that is derived with equations
based on gradients of the prediction samples and a motion
difference relative to coding-unit (CU) motion vectors.
Furthermore, merge with motion vector difference (MMVD) is a
special mode that further signals a limited set of motion vector
differences on top of merge mode. In addition to MMVD, there are
another three types of special merge modes, i.e., sub-block merge,
triangle, and combined intra/inter prediction (CIIP). The sub-
block merge list includes one candidate of sub-block temporal
motion vector prediction (SbTMVP) and up to four candidates of
affine motion vectors. Triangle is based on triangular block
motion compensation. CIIP combines intra and inter predictions
with weighting. Adaptive weighting may be employed with a block-
level tool called bi-prediction with CU-based weighting (BCW),
which provides more flexibility than in HEVC.
Compared to HEVC, VVC introduces several improvements in this area. Intra prediction and intra coding
First, there is the adaptive motion vector resolution (AMVR), which To capture the diversified local image texture directions with
can save bit cost for motion vectors by adaptively signaling motion finer granularity, VVC supports 65 angular directions instead of
vector resolution. Then the affine motion compensation is included 33 directions in HEVC. The intra mode coding is based on a 6-
to capture complicated motion like zooming and rotation. Meanwhile, most-probable-modes scheme, and the 6 most probable modes are
prediction refinement with the optical flow with affine mode (PROF) derived using the neighboring intra prediction directions. In
is further deployed to mimic affine motion at the pixel level. addition, to deal with the different distributions of intra
Thirdly the decoder side motion vector refinement (DMVR) is a method prediction angles for different block aspect ratios, a wide-angle-
to derive MV vector at decoder side based on block matching so that intra-prediction (WAIP) scheme is applied in VVC by including
fewer bits may be spent on motion vectors. Bi-directional optical intra prediction angles beyond those present in HEVC. Unlike
flow (BDOF) is a similar method to PROF. BDOF adds a sample wise HEVC, which only allows using the most adjacent line of reference
offset at 4x4 sub-block level that is derived with equations based on samples for intra prediction, VVC also allows using two further
gradients of the prediction samples and a motion difference relative reference lines, known as multi-reference-line (MRL) intra
to CU motion vectors. Furthermore, merge with motion vector prediction. The additional reference lines can be only used for
difference (MMVD) is a special mode, which further signals a limited the 6 most probable intra prediction modes. To capture the strong
set of motion vector differences on top of merge mode. In addition correlation between different color components, in VVC, a cross-
to MMVD, there are another three types of special merge modes, i.e., component linear mode (CCLM) is utilized, which assumes a linear
sub-block merge, triangle, and combined intra-/inter-prediction relationship between the luma sample values and their associated
(CIIP). Sub-block merge list includes one candidate of sub-block chroma samples. For intra prediction, VVC also applies a
temporal motion vector prediction (SbTMVP) and up to four candidates position-dependent prediction combination (PDPC) for refining the
of affine motion vectors. Triangle is based on triangular block prediction samples closer to the intra prediction block boundary.
motion compensation. CIIP combines intra- and inter- predictions Matrix-based intra prediction (MIP) modes are also used in VVC,
with weighting. Adaptive weighting may be employed with a block- which generates an up to 8x8 intra prediction block using a
level tool called bi-prediction with CU based weighting (BCW) which weighted sum of downsampled neighboring reference samples, and the
provides more flexibility than in HEVC. weights are hard-coded constants.
Intra prediction and intra-coding
To capture the diversified local image texture directions with finer
granularity, VVC supports 65 angular directions instead of 33
directions in HEVC. The intra mode coding is based on a 6-most-
probable-mode scheme, and the 6 most probable modes are derived using
the neighboring intra prediction directions. In addition, to deal
with the different distributions of intra prediction angles for
different block aspect ratios, a wide-angle intra prediction (WAIP)
scheme is applied in VVC by including intra prediction angles beyond
those present in HEVC. Unlike HEVC which only allows using the most
adjacent line of reference samples for intra prediction, VVC also
allows using two further reference lines, as known as multi-
reference-line (MRL) intra prediction. The additional reference
lines can be only used for the 6 most probable intra prediction
modes. To capture the strong correlation between different colour
components, in VVC, a cross-component linear mode (CCLM) is utilized
which assumes a linear relationship between the luma sample values
and their associated chroma samples. For intra prediction, VVC also
applies a position-dependent prediction combination (PDPC) for
refining the prediction samples closer to the intra prediction block
boundary. Matrix-based intra prediction (MIP) modes are also used in
VVC which generates an up to 8x8 intra prediction block using a
weighted sum of downsampled neighboring reference samples, and the
weights are hardcoded constants.
Other coding-tool features Other coding-tool features
VVC introduces dependent quantization (DQ) to reduce quantization
error by state-based switching between two quantizers.
VVC introduces dependent quantization (DQ) to reduce quantization 1.1.2. Systems and Transport Interfaces (Informative)
error by state-based switching between two quantizers.
1.1.2. Systems and Transport Interfaces (informative)
VVC inherits the basic systems and transport interfaces designs from VVC inherits the basic systems and transport interface designs from
HEVC and AVC. These include the NAL-unit-based syntax structure, the HEVC and AVC. These include the NAL-unit-based syntax structure, the
hierarchical syntax and data unit structure, the supplemental hierarchical syntax and data unit structure, the supplemental
enhancement information (SEI) message mechanism, and the video enhancement information (SEI) message mechanism, and the video
buffering model based on the hypothetical reference decoder (HRD). buffering model based on the hypothetical reference decoder (HRD).
The scalability features of VVC are conceptually similar to the The scalability features of VVC are conceptually similar to the
scalable variant of HEVC known as SHVC. The hierarchical syntax and scalable extension of HEVC, known as SHVC. The hierarchical syntax
data unit structure consists of parameter sets at various levels and data unit structure consists of parameter sets at various levels
(decoder, sequence (pertaining to all), sequence (pertaining to a (i.e., decoder, sequence (pertaining to all), sequence (pertaining to
single), picture), picture-level header parameters, slice-level a single), and picture), picture-level header parameters, slice-level
header parameters, and lower-level parameters. header parameters, and lower-level parameters.
A number of key components that influenced the network abstraction A number of key components that influenced the network abstraction
layer design of VVC as well as this memo are described below layer design of VVC, as well as this memo, are described below
Decoding capability information Decoding capability information
The decoding capability information includes parameters that stay The decoding capability information (DCI) includes parameters that
constant for the lifetime of a VVC bitstream in the duration of a stay constant for the lifetime of a VVC bitstream in the duration
video conference, continuous video stream, and similar--any video of a video conference, continuous video stream, and similar, i.e.,
that is processed by a decoder between setup and teardown. For any video that is processed by a decoder between setup and
streaming, the requirement of constant parameters pertains through teardown. For streaming, the requirement of constant parameters
splicing. Such information includes profile, level, and sub-profile pertains through splicing. Such information includes profile,
information to determine a maximum capability interop point that is level, and sub-profile information to determine a maximum
guaranteed to be never exceeded, even if splicing of video sequences capability interop point that is guaranteed to never be exceeded,
occurs within a session. It further includes constraint fields (most even if splicing of video sequences occurs within a session. It
of which are flags), which can optionally be set to indicate that the further includes constraint fields (most of which are flags),
video bitstream will be constrained in the use of certain features as which can optionally be set to indicate that the video bitstream
indicated by the values of those fields. With this, a bitstream can will be constrained in the use of certain features, as indicated
be labeled as not using certain tools, which allows among other by the values of those fields. With this, a bitstream can be
things for resource allocation in a decoder implementation. labeled as not using certain tools, which allows, among other
things, for resource allocation in a decoder implementation.
Video parameter set Video parameter set
The video parameter set (VPS) pertains to one or more coded video
The video parameter set (VPS) pertains to one or more coded video sequences (CVSs) of multiple layers covering the same range of
sequences (CVSs) of multiple layers covering the same range of access access units and includes, among other information, decoding
units, and includes, among other information, decoding dependency dependency expressed as information for reference-picture-list
expressed as information for reference picture list construction of construction of enhancement layers. The VPS provides a "big
enhancement layers. The VPS provides a "big picture" of a scalable picture" of a scalable sequence, including what types of operation
sequence, including what types of operation points are provided, the points are provided; the profile, tier, and level of the operation
profile, tier, and level of the operation points, and some other points; and some other high-level properties of the bitstream that
high-level properties of the bitstream that can be used as the basis can be used as the basis for session negotiation and content
for session negotiation and content selection, etc. One VPS may be selection, etc. One VPS may be referenced by one or more sequence
referenced by one or more sequence parameter sets. parameter sets.
Sequence parameter set Sequence parameter set
The sequence parameter set (SPS) contains syntax elements
The sequence parameter set (SPS) contains syntax elements pertaining pertaining to a coded layer video sequence (CLVS), which is a
to a coded layer video sequence (CLVS), which is a group of pictures group of pictures belonging to the same layer, starting with a
belonging to the same layer, starting with a random access point, and random access point, and followed by pictures that may depend on
followed by pictures that may depend on each other, until the next each other until the next random access point picture. In MPEG-2,
random access point picture. In MPEG-2, the equivalent of a CVS was the equivalent of a CVS was a group of pictures (GOP), which
a group of pictures (GOP), which normally started with an I frame and normally started with an I frame and was followed by P and B
was followed by P and B frames. While more complex in its options of frames. While more complex in its options of random access
random access points, VVC retains this basic concept. One remarkable points, VVC retains this basic concept. One remarkable difference
difference of VVC is that a CLVS may start with a Gradual Decoding of VVC is that a CLVS may start with a Gradual Decoding Refresh
Refresh (GDR) picture, without requiring presence of traditional (GDR) picture without requiring presence of traditional random
random access points in the bitstream, such as instantaneous decoding access points in the bitstream, such as instantaneous decoding
refresh (IDR) or clean random access (CRA) pictures. In many TV-like refresh (IDR) or clean random access (CRA) pictures. In many TV-
applications, a CVS contains a few hundred milliseconds to a few like applications, a CVS contains a few hundred milliseconds to a
seconds of video. In video conferencing (without switching MCUs few seconds of video. In video conferencing (without switching
involved), a CVS can be as long in duration as the whole session. Multipoint Control Units (MCUs) involved), a CVS can be as long in
duration as the whole session.
Picture and adaptation parameter set Picture and adaptation parameter set
The picture parameter set and the adaptation parameter set (PPS and The picture parameter set (PPS) and the adaptation parameter set
APS, respectively) carry information pertaining to zero or more (APS) carry information pertaining to zero or more pictures and
pictures and zero or more slices, respectively. The PPS contains zero or more slices, respectively. The PPS contains information
information that is likely to stay constant from picture to picture, that is likely to stay constant from picture to picture, at least
at least for pictures for a certain type-whereas the APS contains for pictures for a certain type, whereas the APS contains
information, such as adaptive loop filter coefficients, that are information, such as adaptive loop filter coefficients, that are
likely to change from picture to picture or even within a picture. A likely to change from picture to picture or even within a picture.
single APS is referenced by all slices of the same picture if that A single APS is referenced by all slices of the same picture if
APS contains information about luma mapping with chroma scaling that APS contains information about luma mapping with chroma
(LMCS) or scaling list. Different APSs containing ALF parameters can scaling (LMCS) or a scaling list. Different APSs containing ALF
be referenced by slices of the same picture. parameters can be referenced by slices of the same picture.
Picture header Picture header
A picture header (PH) contains information that is common to all
A Picture Header contains information that is common to all slices slices that belong to the same picture. Being able to send that
that belong to the same picture. Being able to send that information information as a separate NAL unit when pictures are split into
as a separate NAL unit when pictures are split into several slices several slices allows for saving bitrate, compared to repeating
allows for saving bitrate, compared to repeating the same information the same information in all slices. However, there might be
in all slices. However, there might be scenarios where low-bitrate scenarios where low-bitrate video is transmitted using a single
video is transmitted using a single slice per picture. Having a slice per picture. Having a separate NAL unit to convey that
separate NAL unit to convey that information incurs in an overhead information incurs in an overhead for such scenarios. For such
for such scenarios. For such scenarios, the picture header syntax scenarios, the picture header syntax structure is directly
structure is directly included in the slice header, instead of its included in the slice header, instead of its own NAL unit. The
own NAL unit. The mode of the picture header syntax structure being mode of the picture header syntax structure being included in its
included in its own NAL unit or not can only be switched on/off for own NAL unit or not can only be switched on/off for an entire CLVS
an entire CLVS, and can only be switched off when in the entire CLVS and can only be switched off when, in the entire CLVS, each
each picture contains only one slice. picture contains only one slice.
Profile, tier, and level Profile, tier, and level
The profile, tier, and level syntax structures in DCI, VPS, and
The profile, tier and level syntax structures in DCI, VPS and SPS SPS contain profile, tier, and level information for all layers
contain profile, tier, level information for all layers that refer to that refer to the DCI, for layers associated with one or more
the DCI, for layers associated with one or more output layer sets output layer sets specified by the VPS, and for any layer that
specified by the VPS, and for any layer that refers to the SPS, refers to the SPS, respectively.
respectively.
Sub-profiles Sub-profiles
Within the VVC specification, a sub-profile is a 32-bit number,
Within the VVC specification, a sub-profile is a 32-bit number, coded coded according to ITU-T Recommendation T.35, that does not carry
according to ITU-T Rec. T.35, that does not carry a semantics. It is semantics. It is carried in the profile_tier_level structure and
carried in the profile_tier_level structure and hence (potentially) hence is (potentially) present in the DCI, VPS, and SPS. External
present in the DCI, VPS, and SPS. External registration bodies can registration bodies can register a T.35 codepoint with ITU-T
register a T.35 codepoint with ITU-T registration authorities and registration authorities and associate with their registration a
associate with their registration a description of bitstream description of bitstream restrictions beyond the profiles defined
restrictions beyond the profiles defined by ITU-T and ISO/IEC. This by ITU-T and ISO/IEC. This would allow encoder manufacturers to
would allow encoder manufacturers to label the bitstreams generated label the bitstreams generated by their encoder as complying with
by their encoder as complying with such sub-profile. It is expected such sub-profile. It is expected that upstream standardization
that upstream standardization organizations (such as: DVB and ATSC), organizations (such as Digital Video Broadcasting (DVB) and
as well as walled-garden video services will take advantage of this Advanced Television Systems Committee (ATSC)), as well as walled-
labeled system. In contrast to "normal" profiles, it is expected garden video services, will take advantage of this labeled system.
that sub-profiles may indicate encoder choices traditionally left In contrast to "normal" profiles, it is expected that sub-profiles
open in the (decoder-centric) video coding specs, such as GOP may indicate encoder choices traditionally left open in the
structures, minimum/maximum QP values, and the mandatory use of (decoder-centric) video coding specifications, such as GOP
certain tools or SEI messages. structures, minimum/maximum Quantizer Parameter (QP) values, and
the mandatory use of certain tools or SEI messages.
General constraint fields General constraint fields
The profile_tier_level structure carries a considerable number of
The profile_tier_level structure carries a considerable number of constraint fields (most of which are flags), which an encoder can
constraint fields (most of which are flags), which an encoder can use use to indicate to a decoder that it will not use a certain tool
to indicate to a decoder that it will not use a certain tool or or technology. They were included in reaction to a perceived
technology. They were included in reaction to a perceived market market need to label a bitstream as not exercising a certain tool
need for labeled a bitstream as not exercising a certain tool that that has become commercially unviable.
has become commercially unviable.
Temporal scalability support Temporal scalability support
VVC includes support of temporal scalability, by the inclusion of
VVC includes support of temporal scalability, by inclusion of the the signaling of TemporalId in the NAL unit header, the
signaling of TemporalId in the NAL unit header, the restriction that restriction that pictures of a particular temporal sublayer cannot
pictures of a particular temporal sublayer cannot be used for inter be used for inter prediction reference by pictures of a lower
prediction reference by pictures of a lower temporal sublayer, the temporal sublayer, the sub-bitstream extraction process, and the
sub-bitstream extraction process, and the requirement that each sub- requirement that each sub-bitstream extraction output be a
bitstream extraction output be a conforming bitstream. Media-Aware conforming bitstream. Media-Aware Network Elements (MANEs) can
Network Elements (MANEs) can utilize the TemporalId in the NAL unit utilize the TemporalId in the NAL unit header for stream
header for stream adaptation purposes based on temporal scalability. adaptation purposes based on temporal scalability.
Reference picture resampling (RPR) Reference picture resampling (RPR)
In AVC and HEVC, the spatial resolution of pictures cannot change
In AVC and HEVC, the spatial resolution of pictures cannot change unless a new sequence using a new SPS starts, with an intra random
unless a new sequence using a new SPS starts, with an Intra random access point (IRAP) picture. VVC enables picture resolution
access point (IRAP) picture. VVC enables picture resolution change change within a sequence at a position without encoding an IRAP
within a sequence at a position without encoding an IRAP picture, picture, which is always intra coded. This feature is sometimes
which is always intra-coded. This feature is sometimes referred to referred to as reference picture resampling (RPR), as the feature
as reference picture resampling (RPR), as the feature needs needs resampling of a reference picture used for inter prediction
resampling of a reference picture used for inter prediction when that when that reference picture has a different resolution than the
reference picture has a different resolution than the current picture current picture being decoded. RPR allows resolution change
being decoded. RPR allows resolution change without the need of without the need of coding an IRAP picture and hence avoids a
coding an IRAP picture and hence avoids a momentary bit rate spike momentary bit rate spike caused by an IRAP picture in streaming or
caused by an IRAP picture in streaming or video conferencing video conferencing scenarios, e.g., to cope with network condition
scenarios, e.g., to cope with network condition changes. RPR can changes. RPR can also be used in application scenarios wherein
also be used in application scenarios wherein zooming of the entire zooming of the entire video region or some region of interest is
video region or some region of interest is needed. needed.
Spatial, SNR, and multiview scalability Spatial, SNR, and multiview scalability
VVC includes support for spatial, SNR, and multiview scalability. VVC includes support for spatial, SNR, and multiview scalability.
Scalable video coding is widely considered to have technical benefits Scalable video coding is widely considered to have technical
and enrich services for various video applications. Until recently, benefits and enrich services for various video applications.
however, the functionality has not been included in the first version Until recently, however, the functionality has not been included
of specifications of the video codecs. In VVC, however, all those in the first version of specifications of the video codecs. In
forms of scalability are supported in the first version of VVC VVC, however, all those forms of scalability are supported in the
natively through the signaling of the nuh_layer_id in the NAL unit first version of VVC natively through the signaling of the
header, the VPS which associates layers with given nuh_layer_id to nuh_layer_id in the NAL unit header, the VPS that associates
each other, reference picture selection, reference picture resampling layers with the given nuh_layer_id to each other, reference
for spatial scalability, and a number of other mechanisms not picture selection, reference picture resampling for spatial
relevant for this memo. scalability, and a number of other mechanisms not relevant for
this memo.
Spatial scalability Spatial scalability
With the existence of reference picture resampling (RPR), the
With the existence of Reference Picture Resampling (RPR), the
additional burden for scalability support is just a additional burden for scalability support is just a
modification of the high-level syntax (HLS). The inter-layer modification of the high-level syntax (HLS). The inter-layer
prediction is employed in a scalable system to improve the prediction is employed in a scalable system to improve the
coding efficiency of the enhancement layers. In addition to coding efficiency of the enhancement layers. In addition to
the spatial and temporal motion-compensated predictions that the spatial and temporal motion-compensated predictions that
are available in a single-layer codec, the inter-layer are available in a single-layer codec, the inter-layer
prediction in VVC uses the possibly resampled video data of the prediction in VVC uses the possibly resampled video data of the
reconstructed reference picture from a reference layer to reconstructed reference picture from a reference layer to
predict the current enhancement layer. The resampling process predict the current enhancement layer. The resampling process
for inter-layer prediction, when used, is performed at the for inter-layer prediction, when used, is performed at the
block-level, reusing the existing interpolation process for block level, reusing the existing interpolation process for
motion compensation in single-layer coding. It means that no motion compensation in single-layer coding. It means that no
additional resampling process is needed to support spatial additional resampling process is needed to support spatial
scalability. scalability.
SNR scalability SNR scalability
SNR scalability is similar to spatial scalability except that
SNR scalability is similar to spatial scalability except that
the resampling factors are 1:1. In other words, there is no the resampling factors are 1:1. In other words, there is no
change in resolution, but there is inter-layer prediction. change in resolution, but there is inter-layer prediction.
Multiview scalability Multiview scalability
The first version of VVC also supports multiview scalability,
The first version of VVC also supports multiview scalability,
wherein a multi-layer bitstream carries layers representing wherein a multi-layer bitstream carries layers representing
multiple views, and one or more of the represented views can be multiple views, and one or more of the represented views can be
output at the same time. output at the same time.
SEI messages SEI messages
Supplemental enhancement information (SEI) messages are
information in the bitstream that do not influence the decoding
process as specified in the VVC specification but address issues
of representation/rendering of the decoded bitstream, label the
bitstream for certain applications, and other, similar tasks. The
overall concept of SEI messages and many of the messages
themselves has been inherited from the AVC and HEVC
specifications. Except for the SEI messages that affect the
specification of the hypothetical reference decoder (HRD), other
SEI messages for use in the VVC environment, which are generally
useful also in other video coding technologies, are not included
in the main VVC specification but in a companion specification
[VSEI].
Supplemental enhancement information (SEI) messages are information 1.1.3. High-Level Picture Partitioning (Informative)
in the bitstream that do not influence the decoding process as
specified in the VVC spec, but address issues of representation/
rendering of the decoded bitstream, label the bitstream for certain
applications, among other, similar tasks. The overall concept of SEI
messages and many of the messages themselves has been inherited from
the AVC and HEVC specs. Except for the SEI messages that affect the
specification of the hypothetical reference decoder (HRD), other SEI
messages for use in the VVC environment, which are generally useful
also in other video coding technologies, are not included in the main
VVC specification but in a companion specification [VSEI].
1.1.3. High-Level Picture Partitioning (informative)
VVC inherited the concept of tiles and wavefront parallel processing VVC inherited the concept of tiles and wavefront parallel processing
(WPP) from HEVC, with some minor to moderate differences. The basic (WPP) from HEVC, with some minor to moderate differences. The basic
concept of slices was kept in VVC but designed in an essentially concept of slices was kept in VVC but designed in an essentially
different form. VVC is the first video coding standard that includes different form. VVC is the first video coding standard that includes
subpictures as a feature, which provides the same functionality as subpictures as a feature, which provides the same functionality as
HEVC motion-constrained tile sets (MCTSs) but designed differently to HEVC motion-constrained tile sets (MCTSs) but designed differently to
have better coding efficiency and to be friendlier for usage in have better coding efficiency and to be friendlier for usage in
application systems. More details of these differences are described application systems. More details of these differences are described
below. below.
Tiles and WPP Tiles and WPP
Same as in HEVC, a picture can be split into tile rows and tile
Same as in HEVC, a picture can be split into tile rows and tile columns in VVC, in-picture prediction across tile boundaries is
columns in VVC, in-picture prediction across tile boundaries is disallowed, etc. However, the syntax for signaling of tile
disallowed, etc. However, the syntax for signaling of tile partitioning has been simplified by using a unified syntax design
partitioning has been simplified, by using a unified syntax design for both the uniform and the non-uniform mode. In addition,
for both the uniform and the non-uniform mode. In addition, signaling of entry point offsets for tiles in the slice header is
signaling of entry point offsets for tiles in the slice header is optional in VVC, while it is mandatory in HEVC. The WPP design in
optional in VVC while it is mandatory in HEVC. The WPP design in VVC VVC has two differences compared to HEVC: i) the CTU row delay is
has two differences compared to HEVC: i) The CTU row delay is reduced reduced from two CTUs to one CTU, and ii) signaling of entry point
from two CTUs to one CTU; ii) signaling of entry point offsets for offsets for WPP in the slice header is optional in VVC while it is
WPP in the slice header is optional in VVC while it is mandatory in mandatory in HEVC.
HEVC.
Slices Slices
In VVC, the conventional slices based on CTUs (as in HEVC) or
macroblocks (as in AVC) have been removed. The main reasoning
behind this architectural change is as follows. The advances in
video coding since 2003 (the publication year of AVC v1) have been
such that slice-based error concealment has become practically
impossible due to the ever-increasing number and efficiency of in-
picture and inter-picture prediction mechanisms. An error-
concealed picture is the decoding result of a transmitted coded
picture for which there is some data loss (e.g., loss of some
slices) of the coded picture or a reference picture, as at least
some part of the coded picture is not error-free (e.g., that
reference picture was an error-concealed picture). For example,
when one of the multiple slices of a picture is lost, it may be
error-concealed using an interpolation of the neighboring slices.
While advanced video coding prediction mechanisms provide
significantly higher coding efficiency, they also make it harder
for machines to estimate the quality of an error-concealed
picture, which was already a hard problem with the use of simpler
prediction mechanisms. Advanced in-picture prediction mechanisms
also cause the coding efficiency loss due to splitting a picture
into multiple slices to be more significant. Furthermore, network
conditions become significantly better while, at the same time,
techniques for dealing with packet losses have become
significantly improved. As a result, very few implementations
have recently used slices for maximum-transmission-unit-size
matching. Instead, substantially all applications where low-delay
error resilience is required (e.g., video telephony and video
conferencing) rely on system/transport-level error resilience
(e.g., retransmission or forward error correction) and/or picture-
based error resilience tools (e.g., feedback-based error
resilience, insertion of IRAPs, scalability with a higher
protection level of the base layer, and so on). Considering all
the above, nowadays, it is very rare that a picture that cannot be
correctly decoded is passed to the decoder, and when such a rare
case occurs, the system can afford to wait for an error-free
picture to be decoded and available for display without resulting
in frequent and long periods of picture freezing seen by end
users.
In VVC, the conventional slices based on CTUs (as in HEVC) or Slices in VVC have two modes: rectangular slices and raster-scan
macroblocks (as in AVC) have been removed. The main reasoning behind slices. The rectangular slice, as indicated by its name, covers a
this architectural change is as follows. The advances in video rectangular region of the picture. Typically, a rectangular slice
coding since 2003 (the publication year of AVC v1) have been such consists of several complete tiles. However, it is also possible
that slice-based error concealment has become practically impossible, that a rectangular slice is a subset of a tile and consists of one
due to the ever-increasing number and efficiency of in-picture and or more consecutive, complete CTU rows within a tile. A raster-
inter-picture prediction mechanisms. An error-concealed picture is scan slice consists of one or more complete tiles in a tile
the decoding result of a transmitted coded picture for which there is raster-scan order; hence, the region covered by raster-scan slices
some data loss (e.g., loss of some slices) of the coded picture or a need not but could have a non-rectangular shape, but it may also
reference picture for at least some part of the coded picture is not happen to have the shape of a rectangle. The concept of slices in
error-free (e.g., that reference picture was an error-concealed VVC is therefore strongly linked to or based on tiles instead of
picture). For example, when one of the multiple slices of a picture CTUs (as in HEVC) or macroblocks (as in AVC).
is lost, it may be error-concealed using an interpolation of the
neighboring slices. While advanced video coding prediction
mechanisms provide significantly higher coding efficiency, they also
make it harder for machines to estimate the quality of an error-
concealed picture, which was already a hard problem with the use of
simpler prediction mechanisms. Advanced in-picture prediction
mechanisms also cause the coding efficiency loss due to splitting a
picture into multiple slices to be more significant. Furthermore,
network conditions become significantly better while at the same time
techniques for dealing with packet losses have become significantly
improved. As a result, very few implementations have recently used
slices for maximum transmission unit size matching. Instead,
substantially all applications where low-delay error resilience is
required (e.g., video telephony and video conferencing) rely on
system/transport-level error resilience (e.g., retransmission,
forward error correction) and/or picture-based error resilience tools
(feedback-based error resilience, insertion of IRAPs, scalability
with higher protection level of the base layer, and so on).
Considering all the above, nowadays it is very rare that a picture
that cannot be correctly decoded is passed to the decoder, and when
such a rare case occurs, the system can afford to wait for an error-
free picture to be decoded and available for display without
resulting in frequent and long periods of picture freezing seen by
end users.
Slices in VVC have two modes: rectangular slices and raster-scan
slices. The rectangular slice, as indicated by its name, covers a
rectangular region of the picture. Typically, a rectangular slice
consists of several complete tiles. However, it is also possible
that a rectangular slice is a subset of a tile and consists of one or
more consecutive, complete CTU rows within a tile. A raster-scan
slice consists of one or more complete tiles in a tile raster scan
order, hence the region covered by a raster-scan slices need not but
could have a non-rectangular shape, but it may also happen to have
the shape of a rectangle. The concept of slices in VVC is therefore
strongly linked to or based on tiles instead of CTUs (as in HEVC) or
macroblocks (as in AVC).
Subpictures Subpictures
VVC is the first video coding standard that includes the support
of subpictures as a feature. Each subpicture consists of one or
more complete rectangular slices that collectively cover a
rectangular region of the picture. A subpicture may be either
specified to be extractable (i.e., coded independently of other
subpictures of the same picture and of earlier pictures in
decoding order) or not extractable. Regardless of whether a
subpicture is extractable or not, the encoder can control whether
in-loop filtering (including deblocking, SAO, and ALF) is applied
across the subpicture boundaries individually for each subpicture.
VVC is the first video coding standard that includes the support of Functionally, subpictures are similar to the motion-constrained
subpictures as a feature. Each subpicture consists of one or more tile sets (MCTSs) in HEVC. They both allow independent coding and
complete rectangular slices that collectively cover a rectangular extraction of a rectangular subset of a sequence of coded pictures
region of the picture. A subpicture may be either specified to be for use cases like viewport-dependent 360-degree video streaming
extractable (i.e., coded independently of other subpictures of the optimization and region of interest (ROI) applications.
same picture and of earlier pictures in decoding order) or not
extractable. Regardless of whether a subpicture is extractable or
not, the encoder can control whether in-loop filtering (including
deblocking, SAO, and ALF) is applied across the subpicture boundaries
individually for each subpicture.
Functionally, subpictures are similar to the motion-constrained tile
sets (MCTSs) in HEVC. They both allow independent coding and
extraction of a rectangular subset of a sequence of coded pictures,
for use cases like viewport-dependent 360o video streaming
optimization and region of interest (ROI) applications.
There are several important design differences between subpictures There are several important design differences between subpictures
and MCTSs. First, the subpictures feature in VVC allows motion and MCTSs. First, the subpictures featured in VVC allow motion
vectors of a coding block pointing outside of the subpicture even vectors of a coding block to point outside of the subpicture, even
when the subpicture is extractable by applying sample padding at when the subpicture is extractable by applying sample padding at
subpicture boundaries in this case, similarly as at picture the subpicture boundaries, in this case, similarly as at picture
boundaries. Second, additional changes were introduced for the boundaries. Second, additional changes were introduced for the
selection and derivation of motion vectors in the merge mode and in selection and derivation of motion vectors in the merge mode and
the decoder side motion vector refinement process of VVC. This in the decoder-side motion vector refinement process of VVC. This
allows higher coding efficiency compared to the non-normative motion allows higher coding efficiency compared to the non-normative
constraints applied at the encoder-side for MCTSs. Third, rewriting motion constraints applied at the encoder-side for MCTSs. Third,
of SHs (and PH NAL units, when present) is not needed when extracting rewriting of slice headers (SHs) (and PH NAL units, when present)
one or more extractable subpictures from a sequence of pictures to is not needed when extracting one or more extractable subpictures
create a sub-bitstream that is a conforming bitstream. In sub- from a sequence of pictures to create a sub-bitstream that is a
bitstream extractions based on HEVC MCTSs, rewriting of SHs is conforming bitstream. In sub-bitstream extractions based on HEVC
needed. Note that in both HEVC MCTSs extraction and VVC subpictures MCTSs, rewriting of SHs is needed. Note that, in both HEVC MCTSs
extraction, rewriting of SPSs and PPSs is needed. However, typically extraction and VVC subpictures extraction, rewriting of SPSs and
there are only a few parameter sets in a bitstream, while each PPSs is needed. However, typically, there are only a few
picture has at least one slice, therefore rewriting of SHs can be a parameter sets in a bitstream, whereas each picture has at least
significant burden for application systems. Fourth, slices of one slice; therefore, rewriting of SHs can be a significant burden
different subpictures within a picture are allowed to have different for application systems. Fourth, slices of different subpictures
NAL unit types. Fifth, VVC specifies HRD and level definitions for within a picture are allowed to have different NAL unit types.
subpicture sequences, thus the conformance of the sub-bitstream of Fifth, VVC specifies HRD and level definitions for subpicture
each extractable subpicture sequence can be ensured by encoders. sequences, thus the conformance of the sub-bitstream of each
extractable subpicture sequence can be ensured by encoders.
1.1.4. NAL Unit Header 1.1.4. NAL Unit Header
VVC maintains the NAL unit concept of HEVC with modifications. VVC VVC maintains the NAL unit concept of HEVC with modifications. VVC
uses a two-byte NAL unit header, as shown in Figure 1. The payload uses a two-byte NAL unit header, as shown in Figure 1. The payload
of a NAL unit refers to the NAL unit excluding the NAL unit header. of a NAL unit refers to the NAL unit excluding the NAL unit header.
+---------------+---------------+ +---------------+---------------+
|0|1|2|3|4|5|6|7|0|1|2|3|4|5|6|7| |0|1|2|3|4|5|6|7|0|1|2|3|4|5|6|7|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|F|Z| LayerID | Type | TID | |F|Z| LayerID | Type | TID |
+---------------+---------------+ +---------------+---------------+
The Structure of the VVC NAL Unit Header. Figure 1: The Structure of the VVC NAL Unit Header
Figure 1
The semantics of the fields in the NAL unit header are as specified The semantics of the fields in the NAL unit header are as specified
in VVC and described briefly below for convenience. In addition to in VVC and described briefly below for convenience. In addition to
the name and size of each field, the corresponding syntax element the name and size of each field, the corresponding syntax element
name in VVC is also provided. name in VVC is also provided.
F: 1 bit F: 1 bit
forbidden_zero_bit. This field is required to be zero in VVC.
forbidden_zero_bit. Required to be zero in VVC. Note that the Note that the inclusion of this bit in the NAL unit header was to
inclusion of this bit in the NAL unit header was to enable enable transport of VVC video over MPEG-2 transport systems
transport of VVC video over MPEG-2 transport systems (avoidance of (avoidance of start code emulations) [MPEG2S]. In the context of
start code emulations) [MPEG2S]. In the context of this payload this payload format, the value 1 may be used to indicate a syntax
format, the value 1 may be used to indicate a syntax violation, violation, e.g., for a NAL unit resulted from aggregating a number
e.g., for a NAL unit resulted from aggregating a number of of fragmented units of a NAL unit but missing the last fragment,
fragmented units of a NAL unit but missing the last fragment, as as described in the last sentence of Section 4.3.3.
described in the last sentence of section 4.3.3.
Z: 1 bit Z: 1 bit
nuh_reserved_zero_bit. This field is required to be zero in VVC,
nuh_reserved_zero_bit. Required to be zero in VVC, and reserved and reserved for future extensions by ITU-T and ISO/IEC.
for future extensions by ITU-T and ISO/IEC. This memo does not overload the "Z" bit for local extensions a)
This memo does not overload the "Z" bit for local extensions, as because overloading the "F" bit is sufficient and b) in order to
a) overloading the "F" bit is sufficient and b) to preserve the preserve the usefulness of this memo to possible future versions
usefulness of this memo to possible future versions of [VVC]. of [VVC].
LayerId: 6 bits LayerId: 6 bits
nuh_layer_id. This field identifies the layer a NAL unit belongs
nuh_layer_id. Identifies the layer a NAL unit belongs to, wherein to, wherein a layer may be, e.g., a spatial scalable layer, a
a layer may be, e.g., a spatial scalable layer, a quality scalable quality scalable layer, a layer containing a different view, etc.
layer, a layer containing a different view, etc.
Type: 5 bits Type: 5 bits
nal_unit_type. This field specifies the NAL unit type, as defined
nal_unit_type. This field specifies the NAL unit type as defined
in Table 5 of [VVC]. For a reference of all currently defined NAL in Table 5 of [VVC]. For a reference of all currently defined NAL
unit types and their semantics, please refer to Section 7.4.2.2 in unit types and their semantics, please refer to Section 7.4.2.2 in
[VVC]. [VVC].
TID: 3 bits TID: 3 bits
nuh_temporal_id_plus1. This field specifies the temporal nuh_temporal_id_plus1. This field specifies the temporal
identifier of the NAL unit plus 1. The value of TemporalId is identifier of the NAL unit plus 1. The value of TemporalId is
equal to TID minus 1. A TID value of 0 is illegal to ensure that equal to TID minus 1. A TID value of 0 is illegal to ensure that
there is at least one bit in the NAL unit header equal to 1, so to there is at least one bit in the NAL unit header equal to 1 in
enable the consideration of start code emulations in the NAL unit order to enable the consideration of start code emulations in the
payload data independent of the NAL unit header. NAL unit payload data independent of the NAL unit header.
1.2. Overview of the Payload Format 1.2. Overview of the Payload Format
This payload format defines the following processes required for This payload format defines the following processes required for
transport of VVC coded data over RTP [RFC3550]: transport of VVC coded data over RTP [RFC3550]:
* Usage of RTP header with this payload format * usage of the RTP header with this payload format
* Packetization of VVC coded NAL units into RTP packets using three * packetization of VVC coded NAL units into RTP packets using three
types of payload structures: a single NAL unit packet, aggregation types of payload structures: a single NAL unit packet, aggregation
packet, and fragment unit packet, and fragment unit
* Transmission of VVC NAL units of the same bitstream within a * transmission of VVC NAL units of the same bitstream within a
single RTP stream single RTP stream
* Media type parameters to be used with the Session Description * media type parameters to be used with the Session Description
Protocol (SDP) [RFC8866] Protocol (SDP) [RFC8866]
* Usage of RTCP feedback messages * usage of RTCP feedback messages
2. Conventions 2. Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. Definitions and Abbreviations 3. Definitions and Abbreviations
3.1. Definitions 3.1. Definitions
This document uses the terms and definitions of VVC. Section 3.1.1 This document uses the terms and definitions of VVC. Section 3.1.1
lists relevant definitions from [VVC] for convenience. Section 3.1.2 lists relevant definitions from [VVC] for convenience. Section 3.1.2
provides definitions specific to this memo. All the used terms and provides definitions specific to this memo. All the used terms and
definitions in this memo are verbatim copies of [VVC] specification. definitions in this memo are verbatim copies from the [VVC]
specification.
3.1.1. Definitions from the VVC Specification 3.1.1. Definitions from the VVC Specification
Access unit (AU): A set of PUs that belong to different layers and Access unit (AU):
contain coded pictures associated with the same time for output from A set of PUs that belong to different layers and contain coded
the DPB. pictures associated with the same time for output from the DPB.
Adaptation parameter set (APS): A syntax structure containing syntax Adaptation parameter set (APS):
elements that apply to zero or more slices as determined by zero or A syntax structure containing syntax elements that apply to zero
more syntax elements found in slice headers. or more slices as determined by zero or more syntax elements found
in slice headers.
Bitstream: A sequence of bits, in the form of a NAL unit stream or a Bitstream:
byte stream, that forms the representation of a sequence of AUs A sequence of bits, in the form of a NAL unit stream or a byte
forming one or more coded video sequences (CVSs). stream, that forms the representation of a sequence of AUs forming
one or more coded video sequences (CVSs).
Coded picture: A coded representation of a picture comprising VCL NAL Coded picture:
units with a particular value of nuh_layer_id within an AU and A coded representation of a picture comprising VCL NAL units with
containing all CTUs of the picture. a particular value of nuh_layer_id within an AU and containing all
CTUs of the picture.
Clean random access (CRA) PU: A PU in which the coded picture is a Clean random access (CRA) PU:
CRA picture. A PU in which the coded picture is a CRA picture.
Clean random access (CRA) picture: An IRAP picture for which each VCL Clean random access (CRA) picture:
NAL unit has nal_unit_type equal to CRA_NUT. An IRAP picture for which each VCL NAL unit has nal_unit_type
equal to CRA_NUT.
Coded video sequence (CVS): A sequence of AUs that consists, in Coded video sequence (CVS):
decoding order, of a CVSS AU, followed by zero or more AUs that are A sequence of AUs that consists, in decoding order, of a CVSS AU,
not CVSS AUs, including all subsequent AUs up to but not including followed by zero or more AUs that are not CVSS AUs, including all
any subsequent AU that is a CVSS AU. subsequent AUs up to but not including any subsequent AU that is a
CVSS AU.
Coded video sequence start (CVSS) AU: An AU in which there is a PU Coded video sequence start (CVSS) AU:
for each layer in the CVS and the coded picture in each PU is a CLVSS An AU in which there is a PU for each layer in the CVS and the
picture. coded picture in each PU is a CLVSS picture.
Coded layer video sequence (CLVS): A sequence of PUs with the same Coded layer video sequence (CLVS):
value of nuh_layer_id that consists, in decoding order, of a CLVSS A sequence of PUs with the same value of nuh_layer_id that
PU, followed by zero or more PUs that are not CLVSS PUs, including consists, in decoding order, of a CLVSS PU, followed by zero or
all subsequent PUs up to but not including any subsequent PU that is more PUs that are not CLVSS PUs, including all subsequent PUs up
a CLVSS PU. to but not including any subsequent PU that is a CLVSS PU.
Coded layer video sequence start (CLVSS) PU: A PU in which the coded Coded layer video sequence start (CLVSS) PU:
picture is a CLVSS picture. A PU in which the coded picture is a CLVSS picture.
Coded layer video sequence start (CLVSS) picture: A coded picture Coded layer video sequence start (CLVSS) picture:
that is an IRAP picture with NoOutputBeforeRecoveryFlag equal to 1 or A coded picture that is an IRAP picture with
a GDR picture with NoOutputBeforeRecoveryFlag equal to 1. NoOutputBeforeRecoveryFlag equal to 1 or a GDR picture with
NoOutputBeforeRecoveryFlag equal to 1.
Coding tree unit (CTU): A CTB of luma samples, two corresponding CTBs Coding Tree Block (CTB):
of chroma samples of a picture that has three sample arrays, or a CTB An NxN block of samples for some value of N such that the division
of samples of a monochrome picture or a picture that is coded using of a component into CTBs is a partitioning.
three separate colour planes and syntax structures used to code the
samples.
Decoding Capability Information (DCI): A syntax structure containing Coding tree unit (CTU):
syntax elements that apply to the entire bitstream. A CTB of luma samples, two corresponding CTBs of chroma samples of
a picture that has three sample arrays, or a CTB of samples of a
monochrome picture or a picture that is coded using three separate
colour planes and syntax structures used to code the samples.
Decoded picture buffer (DPB): A buffer holding decoded pictures for Coding Unit (CU):
reference, output reordering, or output delay specified for the A coding block of luma samples, two corresponding coding blocks of
hypothetical reference decoder. chroma samples of a picture that has three sample arrays in the
single tree mode, or a coding block of luma samples of a picture
that has three sample arrays in the dual tree mode, or two coding
blocks of chroma samples of a picture that has three sample arrays
in the dual tree mode, or a coding block of samples of a
monochrome picture, and syntax structures used to code the
samples.
Gradual decoding refresh (GDR) picture: A picture for which each VCL Decoding Capability Information (DCI):
NAL unit has nal_unit_type equal to GDR_NUT. A syntax structure containing syntax elements that apply to the
entire bitstream.
Instantaneous decoding refresh (IDR) PU: A PU in which the coded Decoded picture buffer (DPB):
picture is an IDR picture. A buffer holding decoded pictures for reference, output
reordering, or output delay specified for the hypothetical
reference decoder.
Instantaneous decoding refresh (IDR) picture: An IRAP picture for Gradual decoding refresh (GDR) picture:
which each VCL NAL unit has nal_unit_type equal to IDR_W_RADL or A picture for which each VCL NAL unit has nal_unit_type equal to
IDR_N_LP. GDR_NUT.
Intra random access point (IRAP) AU: An AU in which there is a PU for Instantaneous decoding refresh (IDR) PU:
each layer in the CVS and the coded picture in each PU is an IRAP A PU in which the coded picture is an IDR picture.
picture.
Intra random access point (IRAP) PU: A PU in which the coded picture Instantaneous decoding refresh (IDR) picture:
is an IRAP picture. An IRAP picture for which each VCL NAL unit has nal_unit_type
equal to IDR_W_RADL or IDR_N_LP.
Intra random access point (IRAP) picture: A coded picture for which Intra random access point (IRAP) AU:
all VCL NAL units have the same value of nal_unit_type in the range An AU in which there is a PU for each layer in the CVS and the
of IDR_W_RADL to CRA_NUT, inclusive. coded picture in each PU is an IRAP picture.
Layer: A set of VCL NAL units that all have a particular value of Intra random access point (IRAP) PU:
nuh_layer_id and the associated non-VCL NAL units. A PU in which the coded picture is an IRAP picture.
Network abstraction layer (NAL) unit: A syntax structure containing Intra random access point (IRAP) picture:
an indication of the type of data to follow and bytes containing that A coded picture for which all VCL NAL units have the same value of
data in the form of an RBSP interspersed as necessary with emulation nal_unit_type in the range of IDR_W_RADL to CRA_NUT, inclusive.
prevention bytes.
Network abstraction layer (NAL) unit stream: A sequence of NAL units. Layer:
A set of VCL NAL units that all have a particular value of
nuh_layer_id and the associated non-VCL NAL units.
Output Layer Set (OLS): A set of layers for which one or more layers Network abstraction layer (NAL) unit:
are specified as the output layers. A syntax structure containing an indication of the type of data to
follow and bytes containing that data in the form of an RBSP
interspersed as necessary with emulation prevention bytes.
Operation point (OP): A temporal subset of an OLS, identified by an Network abstraction layer (NAL) unit stream:
OLS index and a highest value of TemporalId. A sequence of NAL units.
Picture parameter set (PPS): A syntax structure containing syntax Output Layer Set (OLS):
elements that apply to zero or more entire coded pictures as A set of layers for which one or more layers are specified as the
determined by a syntax element found in each slice header. output layers.
Picture unit (PU): A set of NAL units that are associated with each Operation point (OP):
other according to a specified classification rule, are consecutive A temporal subset of an OLS, identified by an OLS index and a
in decoding order, and contain exactly one coded picture. highest value of TemporalId.
Random access: The act of starting the decoding process for a Picture Header (PH):
bitstream at a point other than the beginning of the stream. A syntax structure containing syntax elements that apply to all
slices of a coded picture.
Sequence parameter set (SPS): A syntax structure containing syntax Picture parameter set (PPS):
elements that apply to zero or more entire CLVSs as determined by the A syntax structure containing syntax elements that apply to zero
content of a syntax element found in the PPS referred to by a syntax or more entire coded pictures as determined by a syntax element
element found in each picture header. found in each slice header.
Slice: An integer number of complete tiles or an integer number of Picture unit (PU):
consecutive complete CTU rows within a tile of a picture that are A set of NAL units that are associated with each other according
exclusively contained in a single NAL unit. to a specified classification rule, are consecutive in decoding
order, and contain exactly one coded picture.
Slice header (SH): A part of a coded slice containing the data Random access:
elements pertaining to all tiles or CTU rows within a tile The act of starting the decoding process for a bitstream at a
represented in the slice. point other than the beginning of the bitstream.
Sublayer: A temporal scalable layer of a temporal scalable bitstream Raw Byte Sequence Payload (RBSP):
consisting of VCL NAL units with a particular value of the TemporalId A syntax structure containing an integer number of bytes that is
variable, and the associated non-VCL NAL units. encapsulated in a NAL unit and is either empty or has the form of
a string of data bits containing syntax elements followed by an
RBSP stop bit and zero or more subsequent bits equal to 0.
Subpicture: An rectangular region of one or more slices within a Sequence parameter set (SPS):
picture. A syntax structure containing syntax elements that apply to zero
or more entire CLVSs as determined by the content of a syntax
element found in the PPS referred to by a syntax element found in
each picture header.
Sublayer representation: A subset of the bitstream consisting of NAL Slice:
units of a particular sublayer and the lower sublayers. An integer number of complete tiles or an integer number of
consecutive complete CTU rows within a tile of a picture that are
exclusively contained in a single NAL unit.
Tile: A rectangular region of CTUs within a particular tile column Slice header (SH):
and a particular tile row in a picture. A part of a coded slice containing the data elements pertaining to
all tiles or CTU rows within a tile represented in the slice.
Tile column: A rectangular region of CTUs having a height equal to Sublayer:
the height of the picture and a width specified by syntax elements in A temporal scalable layer of a temporal scalable bitstream
the picture parameter set. consisting of VCL NAL units with a particular value of the
TemporalId variable, and the associated non-VCL NAL units.
Tile row: A rectangular region of CTUs having a height specified by Subpicture:
syntax elements in the picture parameter set and a width equal to the A rectangular region of one or more slices within a picture.
width of the picture.
Video coding layer (VCL) NAL unit: A collective term for coded slice Sublayer representation:
NAL units and the subset of NAL units that have reserved values of A subset of the bitstream consisting of NAL units of a particular
nal_unit_type that are classified as VCL NAL units in this sublayer and the lower sublayers.
Specification.
Tile:
A rectangular region of CTUs within a particular tile column and a
particular tile row in a picture.
Tile column:
A rectangular region of CTUs having a height equal to the height
of the picture and a width specified by syntax elements in the
picture parameter set.
Tile row:
A rectangular region of CTUs having a height specified by syntax
elements in the picture parameter set and a width equal to the
width of the picture.
Video coding layer (VCL) NAL unit:
A collective term for coded slice NAL units and the subset of NAL
units that have reserved values of nal_unit_type that are
classified as VCL NAL units in this Specification.
3.1.2. Definitions Specific to This Memo 3.1.2. Definitions Specific to This Memo
Media-Aware Network Element (MANE): A network element, such as a Media-Aware Network Element (MANE):
middlebox, selective forwarding unit, or application-layer gateway A network element, such as a middlebox, selective forwarding unit,
that is capable of parsing certain aspects of the RTP payload headers or application-layer gateway that is capable of parsing certain
or the RTP payload and reacting to their contents. aspects of the RTP payload headers or the RTP payload and reacting
to their contents.
Informative note: The concept of a MANE goes beyond normal routers | Informative note: The concept of a MANE goes beyond normal
or gateways in that a MANE has to be aware of the signaling (e.g., | routers or gateways in that a MANE has to be aware of the
to learn about the payload type mappings of the media streams), | signaling (e.g., to learn about the payload type mappings of
and in that it has to be trusted when working with Secure RTP | the media streams), and in that it has to be trusted when
(SRTP). The advantage of using MANEs is that they allow packets | working with Secure RTP (SRTP). The advantage of using
to be dropped according to the needs of the media coding. For | MANEs is that they allow packets to be dropped according to
example, if a MANE has to drop packets due to congestion on a | the needs of the media coding. For example, if a MANE has
certain link, it can identify and remove those packets whose | to drop packets due to congestion on a certain link, it can
elimination produces the least adverse effect on the user | identify and remove those packets whose elimination produces
experience. After dropping packets, MANEs must rewrite RTCP | the least adverse effect on the user experience. After
packets to match the changes to the RTP stream, as specified in | dropping packets, MANEs must rewrite RTCP packets to match
Section 7 of [RFC3550]. | the changes to the RTP stream, as specified in Section 7 of
| [RFC3550].
NAL unit decoding order: A NAL unit order that conforms to the NAL unit decoding order:
constraints on NAL unit order given in Section 7.4.2.4 in [VVC], A NAL unit order that conforms to the constraints on NAL unit
follow the Order of NAL units in the bitstream. order given in Section 7.4.2.4 in [VVC], follow the order of NAL
units in the bitstream.
RTP stream (See [RFC7656]): Within the scope of this memo, one RTP RTP stream (see [RFC7656]):
stream is utilized to transport a VVC bitstream, which may contain Within the scope of this memo, one RTP stream is utilized to
one or more layers, and each layer may contain one or more temporal transport a VVC bitstream, which may contain one or more layers,
sublayers. and each layer may contain one or more temporal sublayers.
Transmission order: The order of packets in ascending RTP sequence Transmission order:
number order (in modulo arithmetic). Within an aggregation packet, The order of packets in ascending RTP sequence number order (in
the NAL unit transmission order is the same as the order of modulo arithmetic). Within an aggregation packet, the NAL unit
appearance of NAL units in the packet. transmission order is the same as the order of appearance of NAL
units in the packet.
3.2. Abbreviations 3.2. Abbreviations
AU Access Unit AU Access Unit
AP Aggregation Packet AP Aggregation Packet
APS Adaptation Parameter Set APS Adaptation Parameter Set
CTU Coding Tree Unit CTU Coding Tree Unit
CVS Coded Video Sequence
DPB Decoded Picture Buffer CVS Coded Video Sequence
DCI Decoding Capability Information DPB Decoded Picture Buffer
DON Decoding Order Number DCI Decoding Capability Information
FIR Full Intra Request DON Decoding Order Number
FU Fragmentation Unit FIR Full Intra Request
GDR Gradual Decoding Refresh FU Fragmentation Unit
HRD Hypothetical Reference Decoder GDR Gradual Decoding Refresh
IDR Instantaneous Decoding Refresh HRD Hypothetical Reference Decoder
IRAP Intra Random Access Point IDR Instantaneous Decoding Refresh
MANE Media-Aware Network Element IRAP Intra Random Access Point
MTU Maximum Transfer Unit MANE Media-Aware Network Element
NAL Network Abstraction Layer MTU Maximum Transfer Unit
NALU Network Abstraction Layer Unit NAL Network Abstraction Layer
OLS Output Layer Set NALU Network Abstraction Layer Unit
PLI Picture Loss Indication OLS Output Layer Set
PPS Picture Parameter Set PLI Picture Loss Indication
RPSI Reference Picture Selection Indication PPS Picture Parameter Set
SEI Supplemental Enhancement Information RPSI Reference Picture Selection Indication
SLI Slice Loss Indication SEI Supplemental Enhancement Information
SPS Sequence Parameter Set SLI Slice Loss Indication
VCL Video Coding Layer SPS Sequence Parameter Set
VPS Video Parameter Set VCL Video Coding Layer
VPS Video Parameter Set
4. RTP Payload Format 4. RTP Payload Format
4.1. RTP Header Usage 4.1. RTP Header Usage
The format of the RTP header is specified in [RFC3550] (reprinted as The format of the RTP header is specified in [RFC3550] (reprinted as
Figure 2 for convenience). This payload format uses the fields of Figure 2 for convenience). This payload format uses the fields of
the header in a manner consistent with that specification. the header in a manner consistent with that specification.
The RTP payload (and the settings for some RTP header bits) for The RTP payload (and the settings for some RTP header bits) for
aggregation packets and fragmentation units are specified in aggregation packets and fragmentation units are specified in Sections
Section 4.3.2 and Section 4.3.3, respectively. 4.3.2 and 4.3.3, respectively.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|V=2|P|X| CC |M| PT | sequence number | |V=2|P|X| CC |M| PT | sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| timestamp | | timestamp |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| synchronization source (SSRC) identifier | | synchronization source (SSRC) identifier |
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
| contributing source (CSRC) identifiers | | contributing source (CSRC) identifiers |
| .... | | .... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
RTP Header According to [RFC3550] Figure 2: RTP Header According to RFC 3550
Figure 2
The RTP header information to be set according to this RTP payload The RTP header information to be set according to this RTP payload
format is set as follows: format is set as follows:
Marker bit (M): 1 bit Marker bit (M): 1 bit
Set for the last packet, in transmission order, among each set of Set for the last packet, in transmission order, among each set of
packets that contain NAL units of one access unit. This is in packets that contain NAL units of one access unit. This is in
line with the normal use of the M bit in video formats to allow an line with the normal use of the M bit in video formats to allow an
efficient playout buffer handling. efficient playout buffer handling.
Payload Type (PT): 7 bits Payload Type (PT): 7 bits
The assignment of an RTP payload type for this new packet format The assignment of an RTP payload type for this new packet format
is outside the scope of this document and will not be specified is outside the scope of this document and will not be specified
here. The assignment of a payload type has to be performed either here. The assignment of a payload type has to be performed either
through the profile used or in a dynamic way. through the profile used or in a dynamic way.
Sequence Number (SN): 16 bits Sequence Number (SN): 16 bits
Set and used in accordance with [RFC3550]. Set and used in accordance with [RFC3550].
Timestamp: 32 bits Timestamp: 32 bits
The RTP timestamp is set to the sampling timestamp of the content. The RTP timestamp is set to the sampling timestamp of the content.
A 90 kHz clock rate MUST be used. If the NAL unit has no timing A 90 kHz clock rate MUST be used. If the NAL unit has no timing
properties of its own (e.g., parameter set and SEI NAL units), the properties of its own (e.g., parameter set and SEI NAL units), the
RTP timestamp MUST be set to the RTP timestamp of the coded RTP timestamp MUST be set to the RTP timestamp of the coded
pictures of the access unit in which the NAL unit (according to pictures of the access unit in which the NAL unit (according to
Section 7.4.2.4 of [VVC]) is included. Receivers MUST use the RTP Section 7.4.2.4 of [VVC]) is included. Receivers MUST use the RTP
timestamp for the display process, even when the bitstream timestamp for the display process, even when the bitstream
contains picture timing SEI messages or decoding unit information contains picture timing SEI messages or decoding unit information
SEI messages as specified in [VVC]. SEI messages, as specified in [VVC].
Informative note: When picture timing SEI messages are present, | Informative note: When picture timing SEI messages are
the RTP sender is responsible to ensure that the RTP timestamps | present, the RTP sender is responsible to ensure that the
are consistent with the timing information carried in the | RTP timestamps are consistent with the timing information
picture timing SEI messages. | carried in the picture timing SEI messages.
Synchronization source (SSRC): 32 bits Synchronization source (SSRC): 32 bits
Used to identify the source of the RTP packets. A single SSRC is Used to identify the source of the RTP packets. A single SSRC is
used for all parts of a single bitstream. used for all parts of a single bitstream.
4.2. Payload Header Usage 4.2. Payload Header Usage
The first two bytes of the payload of an RTP packet are referred to The first two bytes of the payload of an RTP packet are referred to
as the payload header. The payload header consists of the same as the payload header. The payload header consists of the same
fields (F, Z, LayerId, Type, and TID) as the NAL unit header as shown fields (F, Z, LayerId, Type, and TID) as the NAL unit header shown in
in Section 1.1.4, irrespective of the type of the payload structure. Section 1.1.4, irrespective of the type of the payload structure.
The TID value indicates (among other things) the relative importance The TID value indicates (among other things) the relative importance
of an RTP packet, for example, because NAL units belonging to higher of an RTP packet, for example, because NAL units belonging to higher
temporal sublayers are not used for the decoding of lower temporal temporal sublayers are not used for the decoding of lower temporal
sublayers. A lower value of TID indicates a higher importance. sublayers. A lower value of TID indicates a higher importance. More
More-important NAL units MAY be better protected against transmission important NAL units MAY be better protected against transmission
losses than less-important NAL units. losses than less-important NAL units.
4.3. Payload Structures 4.3. Payload Structures
Three different types of RTP packet payload structures are specified. Three different types of RTP packet payload structures are specified.
A receiver can identify the type of an RTP packet payload through the A receiver can identify the type of an RTP packet payload through the
Type field in the payload header. Type field in the payload header.
The three different payload structures are as follows: The three different payload structures are as follows:
skipping to change at page 23, line 14 skipping to change at line 1079
* Aggregation Packet (AP): Contains more than one NAL unit within * Aggregation Packet (AP): Contains more than one NAL unit within
one access unit. This payload structure is specified in one access unit. This payload structure is specified in
Section 4.3.2. Section 4.3.2.
* Fragmentation Unit (FU): Contains a subset of a single NAL unit. * Fragmentation Unit (FU): Contains a subset of a single NAL unit.
This payload structure is specified in Section 4.3.3. This payload structure is specified in Section 4.3.3.
4.3.1. Single NAL Unit Packets 4.3.1. Single NAL Unit Packets
A single NAL unit packet contains exactly one NAL unit, and consists A single NAL unit packet contains exactly one NAL unit and consists
of a payload header as defined in Table 5 of [VVC] (denoted here as of a payload header, as defined in Table 5 of [VVC] (denoted here as
PayloadHdr), following with a conditional 16-bit DONL field (in PayloadHdr), following with a conditional 16-bit DONL field (in
network byte order), and the NAL unit payload data (the NAL unit network byte order), and the NAL unit payload data (the NAL unit
excluding its NAL unit header) of the contained NAL unit, as shown in excluding its NAL unit header) of the contained NAL unit, as shown in
Figure 3. Figure 3.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PayloadHdr | DONL (conditional) | | PayloadHdr | DONL (conditional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| NAL unit payload data | | NAL unit payload data |
| | | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| :...OPTIONAL RTP padding | | :...OPTIONAL RTP padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Structure of a Single NAL Unit Packet Figure 3: The Structure of a Single NAL Unit Packet
Figure 3
The DONL field, when present, specifies the value of the 16 least The DONL field, when present, specifies the value of the 16 least
significant bits of the decoding order number of the contained NAL significant bits of the decoding order number of the contained NAL
unit. If sprop-max-don-diff (see definition in Section 7.2) is unit. If sprop-max-don-diff (defined in Section 7.2) is greater than
greater than 0, the DONL field MUST be present, and the variable DON 0, the DONL field MUST be present, and the variable DON for the
for the contained NAL unit is derived as equal to the value of the contained NAL unit is derived as equal to the value of the DONL
DONL field. Otherwise (sprop-max-don-diff is equal to 0), the DONL field. Otherwise (sprop-max-don-diff is equal to 0), the DONL field
field MUST NOT be present. MUST NOT be present.
4.3.2. Aggregation Packets (APs) 4.3.2. Aggregation Packets (APs)
Aggregation Packets (APs) can reduce packetization overhead for small Aggregation packets (APs) can reduce packetization overhead for small
NAL units, such as most of the non-VCL NAL units, which are often NAL units, such as most of the non-VCL NAL units, which are often
only a few octets in size. only a few octets in size.
An AP aggregates NAL units of one access unit and it MUST NOT contain An AP aggregates NAL units of one access unit, and it MUST NOT
NAL units from more than one AU. Each NAL unit to be carried in an contain NAL units from more than one AU. Each NAL unit to be carried
AP is encapsulated in an aggregation unit. NAL units aggregated in in an AP is encapsulated in an aggregation unit. NAL units
one AP are included in NAL unit decoding order. aggregated in one AP are included in NAL-unit-decoding order.
An AP consists of a payload header as defined in Table 5 of [VVC] An AP consists of a payload header, as defined in Table 5 of [VVC]
(denoted here as PayloadHdr with Type=28) followed by two or more (denoted here as PayloadHdr with Type=28), followed by two or more
aggregation units, as shown in Figure 4. aggregation units, as shown in Figure 4.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PayloadHdr (Type=28) | | | PayloadHdr (Type=28) | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | | |
| two or more aggregation units | | two or more aggregation units |
| | | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| :...OPTIONAL RTP padding | | :...OPTIONAL RTP padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Structure of an Aggregation Packet Figure 4: The Structure of an Aggregation Packet
Figure 4
The fields in the payload header of an AP are set as follows. The F The fields in the payload header of an AP are set as follows. The F
bit MUST be equal to 0 if the F bit of each aggregated NAL unit is bit MUST be equal to 0 if the F bit of each aggregated NAL unit is
equal to zero; otherwise, it MUST be equal to 1. The Type field MUST equal to zero; otherwise, it MUST be equal to 1. The Type field MUST
be equal to 28. be equal to 28.
The value of LayerId MUST be equal to the lowest value of LayerId of The value of LayerId MUST be equal to the lowest value of LayerId of
all the aggregated NAL units. The value of TID MUST be the lowest all the aggregated NAL units. The value of TID MUST be the lowest
value of TID of all the aggregated NAL units. value of TID of all the aggregated NAL units.
Informative note: All VCL NAL units in an AP have the same TID | Informative note: All VCL NAL units in an AP have the same TID
value since they belong to the same access unit. However, an AP | value since they belong to the same access unit. However, an
may contain non-VCL NAL units for which the TID value in the NAL | AP may contain non-VCL NAL units for which the TID value in the
unit header may be different than the TID value of the VCL NAL | NAL unit header may be different than the TID value of the VCL
units in the same AP. | NAL units in the same AP.
Informative Note: If a system envisions sub-picture level or | Informative note: If a system envisions subpicture-level or
picture level modifications, for example by removing sub-pictures | picture-level modifications, for example, by removing
or pictures of a particular layer, a good design choice on the | subpictures or pictures of a particular layer, a good design
sender's side would be to aggregate NAL units belonging to only | choice on the sender's side would be to aggregate NAL units
the same sub-picture or picture of a particular layer. | belonging to only the same subpicture or picture of a
| particular layer.
An AP MUST carry at least two aggregation units and can carry as many An AP MUST carry at least two aggregation units and can carry as many
aggregation units as necessary; however, the total amount of data in aggregation units as necessary; however, the total amount of data in
an AP obviously MUST fit into an IP packet, and the size SHOULD be an AP obviously MUST fit into an IP packet, and the size SHOULD be
chosen so that the resulting IP packet is smaller than the MTU size chosen so that the resulting IP packet is smaller than the MTU size
so to avoid IP layer fragmentation. An AP MUST NOT contain FUs in order to avoid IP layer fragmentation. An AP MUST NOT contain the
specified in Section 4.3.3. APs MUST NOT be nested; i.e., an AP can FUs specified in Section 4.3.3. APs MUST NOT be nested, i.e., an AP
not contain another AP. cannot contain another AP.
The first aggregation unit in an AP consists of a conditional 16-bit The first aggregation unit in an AP consists of a conditional 16-bit
DONL field (in network byte order) followed by a 16-bit unsigned size DONL field (in network byte order), followed by 16 bits of unsigned
information (in network byte order) that indicates the size of the size information (in network byte order) that indicate the size of
NAL unit in bytes (excluding these two octets, but including the NAL the NAL unit in bytes (excluding these two octets but including the
unit header), followed by the NAL unit itself, including its NAL unit NAL unit header), followed by the NAL unit itself, including its NAL
header, as shown in Figure 5. unit header, as shown in Figure 5.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : DONL (conditional) | NALU size | | : DONL (conditional) | NALU size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NALU size | | | NALU size | |
+-+-+-+-+-+-+-+-+ NAL unit | +-+-+-+-+-+-+-+-+ NAL unit |
| | | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : | :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Structure of the First Aggregation Unit in an AP Figure 5: The Structure of the First Aggregation Unit in an AP
Figure 5
Informative Note: The first octet of Figure 5 (indicated by the | Informative note: The first octet of Figure 5 (indicated by the
first colon) belongs to a previous aggregation unit. It is | first colon) belongs to a previous aggregation unit. It is
depicted to emphasize that aggregation units are octet-aligned | depicted to emphasize that aggregation units are octet aligned
only. Similarly, the NAL unit carried in the aggregation unit can | only. Similarly, the NAL unit carried in the aggregation unit
terminate at the octet boundary. | can terminate at the octet boundary.
The DONL field, when present, specifies the value of the 16 least The DONL field, when present, specifies the value of the 16 least
significant bits of the decoding order number of the aggregated NAL significant bits of the decoding order number of the aggregated NAL
unit. unit.
If sprop-max-don-diff is greater than 0, the DONL field MUST be If sprop-max-don-diff is greater than 0, the DONL field MUST be
present in an aggregation unit that is the first aggregation unit in present in an aggregation unit that is the first aggregation unit in
an AP, and the variable DON for the aggregated NAL unit is derived as an AP, and the variable DON for the aggregated NAL unit is derived as
equal to the value of the DONL field, and the variable DON for an equal to the value of the DONL field, and the variable DON for an
aggregation unit that is not the first aggregation unit in an AP aggregation unit that is not the first aggregation unit in an AP-
aggregated NAL unit is derived as equal to the DON of the preceding aggregated NAL unit is derived as equal to the DON of the preceding
aggregated NAL unit in the same AP plus 1 modulo 65536. Otherwise aggregated NAL unit in the same AP plus 1 modulo 65536. Otherwise
(sprop-max-don-diff is equal to 0), the DONL field MUST NOT be (sprop-max-don-diff is equal to 0), the DONL field MUST NOT be
present in an aggregation unit that is the first aggregation unit in present in an aggregation unit that is the first aggregation unit in
an AP. an AP.
An aggregation unit that is not the first aggregation unit in an AP An aggregation unit that is not the first aggregation unit in an AP
will be followed immediately by a 16-bit unsigned size information will be followed immediately by 16 bits of unsigned size information
(in network byte order) that indicates the size of the NAL unit in (in network byte order) that indicate the size of the NAL unit in
bytes (excluding these two octets, but including the NAL unit bytes (excluding these two octets but including the NAL unit header),
header), followed by the NAL unit itself, including its NAL unit followed by the NAL unit itself, including its NAL unit header, as
header, as shown in Figure 6. shown in Figure 6.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : NALU size | NAL unit | | : NALU size | NAL unit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : | :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Structure of an Aggregation Unit That Is Not the First Figure 6: The Structure of an Aggregation Unit That Is Not the First
Aggregation Unit in an AP Aggregation Unit in an AP
Figure 6
Informative Note: The first octet of Figure 6 (indicated by the | Informative note: The first octet of Figure 6 (indicated by the
first colon) belongs to a previous aggregation unit. It is | first colon) belongs to a previous aggregation unit. It is
depicted to emphasize that aggregation units are octet-aligned | depicted to emphasize that aggregation units are octet aligned
only. Similarly, the NAL unit carried in the aggregation unit can | only. Similarly, the NAL unit carried in the aggregation unit
terminate at the octet boundary. | can terminate at the octet boundary.
Figure 7 presents an example of an AP that contains two aggregation Figure 7 presents an example of an AP that contains two aggregation
units, labeled as 1 and 2 in the figure, without the DONL field being units, labeled as 1 and 2 in the figure, without the DONL field being
present. present.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RTP Header | | RTP Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 27, line 26 skipping to change at line 1260
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| . . . | NALU 2 Size | NALU 2 HDR | | . . . | NALU 2 Size | NALU 2 HDR |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NALU 2 HDR | | | NALU 2 HDR | |
+-+-+-+-+-+-+-+-+ NALU 2 Data | +-+-+-+-+-+-+-+-+ NALU 2 Data |
| . . . | | . . . |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| :...OPTIONAL RTP padding | | :...OPTIONAL RTP padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
An Example of an AP Packet Containing Figure 7: An Example of an AP Packet Containing Two Aggregation
Two Aggregation Units without the DONL Field Units without the DONL Field
Figure 7
Figure 8 presents an example of an AP that contains two aggregation Figure 8 presents an example of an AP that contains two aggregation
units, labeled as 1 and 2 in the figure, with the DONL field being units, labeled as 1 and 2 in the figure, with the DONL field being
present. present.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RTP Header | | RTP Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 28, line 27 skipping to change at line 1289
+ . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| : NALU 2 Size | | : NALU 2 Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NALU 2 HDR | | | NALU 2 HDR | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ NALU 2 Data | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ NALU 2 Data |
| | | |
| . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| :...OPTIONAL RTP padding | | :...OPTIONAL RTP padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
An Example of an AP Containing Figure 8: An Example of an AP Containing Two Aggregation Units
Two Aggregation Units with the DONL Field with the DONL Field
Figure 8
4.3.3. Fragmentation Units 4.3.3. Fragmentation Units
Fragmentation Units (FUs) are introduced to enable fragmenting a Fragmentation Units (FUs) are introduced to enable fragmenting a
single NAL unit into multiple RTP packets, possibly without single NAL unit into multiple RTP packets, possibly without
cooperation or knowledge of the [VVC] encoder. A fragment of a NAL cooperation or knowledge of the [VVC] encoder. A fragment of a NAL
unit consists of an integer number of consecutive octets of that NAL unit consists of an integer number of consecutive octets of that NAL
unit. Fragments of the same NAL unit MUST be sent in consecutive unit. Fragments of the same NAL unit MUST be sent in consecutive
order with ascending RTP sequence numbers (with no other RTP packets order with ascending RTP sequence numbers (with no other RTP packets
within the same RTP stream being sent between the first and last within the same RTP stream being sent between the first and last
fragment). fragment).
When a NAL unit is fragmented and conveyed within FUs, it is referred When a NAL unit is fragmented and conveyed within FUs, it is referred
to as a fragmented NAL unit. APs MUST NOT be fragmented. FUs MUST to as a fragmented NAL unit. APs MUST NOT be fragmented. FUs MUST
NOT be nested; i.e., an FU can not contain a subset of another FU. NOT be nested, i.e., an FU cannot contain a subset of another FU.
The RTP timestamp of an RTP packet carrying an FU is set to the NALU- The RTP timestamp of an RTP packet carrying an FU is set to the NALU-
time of the fragmented NAL unit. time of the fragmented NAL unit.
An FU consists of a payload header as defined in Table 5 of [VVC] An FU consists of a payload header as defined in Table 5 of [VVC]
(denoted here as PayloadHdr with Type=29), an FU header of one octet, (denoted here as PayloadHdr with Type=29), an FU header of one octet,
a conditional 16-bit DONL field (in network byte order), and an FU a conditional 16-bit DONL field (in network byte order), and an FU
payload, as shown in Figure 9. payload (as shown in Figure 9).
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PayloadHdr (Type=29) | FU header | DONL (cond) | | PayloadHdr (Type=29) | FU header | DONL (cond) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
| DONL (cond) | | | DONL (cond) | |
|-+-+-+-+-+-+-+-+ | |-+-+-+-+-+-+-+-+ |
| FU payload | | FU payload |
| | | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| :...OPTIONAL RTP padding | | :...OPTIONAL RTP padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Structure of an FU Figure 9: The Structure of an FU
Figure 9
The fields in the payload header are set as follows. The Type field The fields in the payload header are set as follows. The Type field
MUST be equal to 29. The fields F, LayerId, and TID MUST be equal to MUST be equal to 29. The fields F, LayerId, and TID MUST be equal to
the fields F, LayerId, and TID, respectively, of the fragmented NAL the fields F, LayerId, and TID, respectively, of the fragmented NAL
unit. unit.
The FU header consists of an S bit, an E bit, an R bit and a 5-bit The FU header consists of an S bit, an E bit, an R bit, and a 5-bit
FuType field, as shown in Figure 10. FuType field, as shown in Figure 10.
+---------------+ +---------------+
|0|1|2|3|4|5|6|7| |0|1|2|3|4|5|6|7|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|S|E|P| FuType | |S|E|P| FuType |
+---------------+ +---------------+
The Structure of FU Header Figure 10: The Structure of the FU Header
Figure 10
The semantics of the FU header fields are as follows: The semantics of the FU header fields are as follows:
S: 1 bit S: 1 bit
When set to 1, the S bit indicates the start of a fragmented NAL When set to 1, the S bit indicates the start of a fragmented NAL
unit, i.e., the first byte of the FU payload is also the first unit, i.e., the first byte of the FU payload is also the first
byte of the payload of the fragmented NAL unit. When the FU byte of the payload of the fragmented NAL unit. When the FU
payload is not the start of the fragmented NAL unit payload, the S payload is not the start of the fragmented NAL unit payload, the S
bit MUST be set to 0. bit MUST be set to 0.
skipping to change at page 30, line 11 skipping to change at line 1356
The semantics of the FU header fields are as follows: The semantics of the FU header fields are as follows:
S: 1 bit S: 1 bit
When set to 1, the S bit indicates the start of a fragmented NAL When set to 1, the S bit indicates the start of a fragmented NAL
unit, i.e., the first byte of the FU payload is also the first unit, i.e., the first byte of the FU payload is also the first
byte of the payload of the fragmented NAL unit. When the FU byte of the payload of the fragmented NAL unit. When the FU
payload is not the start of the fragmented NAL unit payload, the S payload is not the start of the fragmented NAL unit payload, the S
bit MUST be set to 0. bit MUST be set to 0.
E: 1 bit E: 1 bit
When set to 1, the E bit indicates the end of a fragmented NAL When set to 1, the E bit indicates the end of a fragmented NAL
unit, i.e., the last byte of the payload is also the last byte of unit, i.e., the last byte of the payload is also the last byte of
the fragmented NAL unit. When the FU payload is not the last the fragmented NAL unit. When the FU payload is not the last
fragment of a fragmented NAL unit, the E bit MUST be set to 0. fragment of a fragmented NAL unit, the E bit MUST be set to 0.
P: 1 bit P: 1 bit
When set to 1, the P bit indicates the last FU of the last VCL NAL When set to 1, the P bit indicates the last FU of the last VCL NAL
unit of a coded picture, i.e., the last byte of the FU payload is unit of a coded picture, i.e., the last byte of the FU payload is
also the last byte of the last VCL NAL unit of the coded picture. also the last byte of the last VCL NAL unit of the coded picture.
When the FU payload is not the last fragment of the last VCL NAL When the FU payload is not the last fragment of the last VCL NAL
unit of a coded picture, the P bit MUST be set to 0. unit of a coded picture, the P bit MUST be set to 0.
FuType: 5 bits FuType: 5 bits
The field FuType MUST be equal to the field Type of the fragmented The field FuType MUST be equal to the field Type of the fragmented
NAL unit. NAL unit.
The DONL field, when present, specifies the value of the 16 least The DONL field, when present, specifies the value of the 16 least
significant bits of the decoding order number of the fragmented NAL significant bits of the decoding order number of the fragmented NAL
unit. unit.
If sprop-max-don-diff is greater than 0, and the S bit is equal to 1, If sprop-max-don-diff is greater than 0, and the S bit is equal to 1,
the DONL field MUST be present in the FU, and the variable DON for the DONL field MUST be present in the FU, and the variable DON for
the fragmented NAL unit is derived as equal to the value of the DONL the fragmented NAL unit is derived as equal to the value of the DONL
field. Otherwise (sprop-max-don-diff is equal to 0, or the S bit is field. Otherwise (sprop-max-don-diff is equal to 0, or the S bit is
equal to 0), the DONL field MUST NOT be present in the FU. equal to 0), the DONL field MUST NOT be present in the FU.
A non-fragmented NAL unit MUST NOT be transmitted in one FU; i.e., A non-fragmented NAL unit MUST NOT be transmitted in one FU, i.e.,
the Start bit and End bit must not both be set to 1 in the same FU the Start bit and End bit must not both be set to 1 in the same FU
header. header.
The FU payload consists of fragments of the payload of the fragmented The FU payload consists of fragments of the payload of the fragmented
NAL unit so that if the FU payloads of consecutive FUs, starting with NAL unit so that, if the FU payloads of consecutive FUs, starting
an FU with the S bit equal to 1 and ending with an FU with the E bit with an FU with the S bit equal to 1 and ending with an FU with the E
equal to 1, are sequentially concatenated, the payload of the bit equal to 1, are sequentially concatenated, the payload of the
fragmented NAL unit can be reconstructed. The NAL unit header of the fragmented NAL unit can be reconstructed. The NAL unit header of the
fragmented NAL unit is not included as such in the FU payload, but fragmented NAL unit is not included as such in the FU payload, but
rather the information of the NAL unit header of the fragmented NAL rather the information of the NAL unit header of the fragmented NAL
unit is conveyed in F, LayerId, and TID fields of the FU payload unit is conveyed in the F, LayerId, and TID fields of the FU payload
headers of the FUs and the FuType field of the FU header of the FUs. headers of the FUs and the FuType field of the FU header of the FUs.
An FU payload MUST NOT be empty. An FU payload MUST NOT be empty.
If an FU is lost, the receiver SHOULD discard all following If an FU is lost, the receiver SHOULD discard all following
fragmentation units in transmission order corresponding to the same fragmentation units in transmission order, corresponding to the same
fragmented NAL unit, unless the decoder in the receiver is known to fragmented NAL unit, unless the decoder in the receiver is known to
be prepared to gracefully handle incomplete NAL units. be prepared to gracefully handle incomplete NAL units.
A receiver in an endpoint or in a MANE MAY aggregate the first n-1 A receiver in an endpoint or in a MANE MAY aggregate the first n-1
fragments of a NAL unit to an (incomplete) NAL unit, even if fragment fragments of a NAL unit to an (incomplete) NAL unit, even if fragment
n of that NAL unit is not received. In this case, the n of that NAL unit is not received. In this case, the
forbidden_zero_bit of the NAL unit MUST be set to 1 to indicate a forbidden_zero_bit of the NAL unit MUST be set to 1 to indicate a
syntax violation. syntax violation.
4.4. Decoding Order Number 4.4. Decoding Order Number
skipping to change at page 32, line 20 skipping to change at line 1445
If (DON[n] < DON[n-1] and DON[n-1] - DON[n] >= 32768), If (DON[n] < DON[n-1] and DON[n-1] - DON[n] >= 32768),
AbsDon[n] = AbsDon[n-1] + 65536 - DON[n-1] + DON[n] AbsDon[n] = AbsDon[n-1] + 65536 - DON[n-1] + DON[n]
If (DON[n] > DON[n-1] and DON[n] - DON[n-1] >= 32768), If (DON[n] > DON[n-1] and DON[n] - DON[n-1] >= 32768),
AbsDon[n] = AbsDon[n-1] - (DON[n-1] + 65536 - DON[n]) AbsDon[n] = AbsDon[n-1] - (DON[n-1] + 65536 - DON[n])
If (DON[n] < DON[n-1] and DON[n-1] - DON[n] < 32768), If (DON[n] < DON[n-1] and DON[n-1] - DON[n] < 32768),
AbsDon[n] = AbsDon[n-1] - (DON[n-1] - DON[n]) AbsDon[n] = AbsDon[n-1] - (DON[n-1] - DON[n])
For any two NAL units m and n, the following applies: For any two NAL units (m and n), the following applies:
* AbsDon[n] greater than AbsDon[m] indicates that NAL unit n follows * When AbsDon[n] is greater than AbsDon[m], this indicates that NAL
NAL unit m in NAL unit decoding order. unit n follows NAL unit m in NAL unit decoding order.
* When AbsDon[n] is equal to AbsDon[m], the NAL unit decoding order * When AbsDon[n] is equal to AbsDon[m], the NAL unit decoding order
of the two NAL units can be in either order. of the two NAL units can be in either order.
* AbsDon[n] less than AbsDon[m] indicates that NAL unit n precedes * When AbsDon[n] is less than AbsDon[m], this indicates that NAL
NAL unit m in decoding order. unit n precedes NAL unit m in decoding order.
Informative note: When two consecutive NAL units in the NAL | Informative note: When two consecutive NAL units in the NAL
unit decoding order have different values of AbsDon, the | unit decoding order have different values of AbsDon, the
absolute difference between the two AbsDon values may be | absolute difference between the two AbsDon values may be
greater than or equal to 1. | greater than or equal to 1.
Informative note: There are multiple reasons to allow for the | Informative note: There are multiple reasons to allow for the
absolute difference of the values of AbsDon for two consecutive | absolute difference of the values of AbsDon for two consecutive
NAL units in the NAL unit decoding order to be greater than | NAL units in the NAL unit decoding order to be greater than
one. An increment by one is not required, as at the time of | one. An increment by one is not required, as at the time of
associating values of AbsDon to NAL units, it may not be known | associating values of AbsDon to NAL units, it may not be known
whether all NAL units are to be delivered to the receiver. For | whether all NAL units are to be delivered to the receiver. For
example, a gateway might not forward VCL NAL units of higher | example, a gateway might not forward VCL NAL units of higher
sublayers or some SEI NAL units when there is congestion in the | sublayers or some SEI NAL units when there is congestion in the
network. In another example, the first intra-coded picture of | network. In another example, the first intra-coded picture of
a pre-encoded clip is transmitted in advance to ensure that it | a pre-encoded clip is transmitted in advance to ensure that it
is readily available in the receiver, and when transmitting the | is readily available in the receiver, and when transmitting the
first intra-coded picture, the originator does not exactly know | first intra-coded picture, the originator does not exactly know
how many NAL units will be encoded before the first intra-coded | how many NAL units will be encoded before the first intra-coded
picture of the pre-encoded clip follows in decoding order. | picture of the pre-encoded clip follows in decoding order.
Thus, the values of AbsDon for the NAL units of the first | Thus, the values of AbsDon for the NAL units of the first
intra-coded picture of the pre-encoded clip have to be | intra-coded picture of the pre-encoded clip have to be
estimated when they are transmitted, and gaps in values of | estimated when they are transmitted, and gaps in values of
AbsDon may occur. | AbsDon may occur.
5. Packetization Rules 5. Packetization Rules
The following packetization rules apply: The following packetization rules apply:
* If sprop-max-don-diff is greater than 0, the transmission order of * If sprop-max-don-diff is greater than 0, the transmission order of
NAL units carried in the RTP stream MAY be different than the NAL NAL units carried in the RTP stream MAY be different than the NAL
unit decoding order. Otherwise (sprop-max-don-diff is equal to unit decoding order. Otherwise (sprop-max-don-diff is equal to
0), the transmission order of NAL units carried in the RTP stream 0), the transmission order of NAL units carried in the RTP stream
MUST be the same as the NAL unit decoding order. MUST be the same as the NAL unit decoding order.
* A NAL unit of a small size SHOULD be encapsulated in an * A NAL unit of a small size SHOULD be encapsulated in an
aggregation packet together with one or more other NAL units in aggregation packet together with one or more other NAL units in
order to avoid the unnecessary packetization overhead for small order to avoid the unnecessary packetization overhead for small
NAL units. For example, non-VCL NAL units such as access unit NAL units. For example, non-VCL NAL units, such as access unit
delimiters, parameter sets, or SEI NAL units are typically small delimiters, parameter sets, or SEI NAL units, are typically small
and can often be aggregated with VCL NAL units without violating and can often be aggregated with VCL NAL units without violating
MTU size constraints. MTU size constraints.
* Each non-VCL NAL unit SHOULD, when possible from an MTU size match * Each non-VCL NAL unit SHOULD, when possible from an MTU size match
viewpoint, be encapsulated in an aggregation packet together with viewpoint, be encapsulated in an aggregation packet together with
its associated VCL NAL unit, as typically a non-VCL NAL unit would its associated VCL NAL unit, as typically a non-VCL NAL unit would
be meaningless without the associated VCL NAL unit being be meaningless without the associated VCL NAL unit being
available. available.
* For carrying exactly one NAL unit in an RTP packet, a single NAL * For carrying exactly one NAL unit in an RTP packet, a single NAL
skipping to change at page 34, line 22 skipping to change at line 1524
the following description should be seen as an example of a suitable the following description should be seen as an example of a suitable
implementation. Other schemes may be used as well, as long as the implementation. Other schemes may be used as well, as long as the
output for the same input is the same as the process described below. output for the same input is the same as the process described below.
The output is the same when the set of output NAL units and their The output is the same when the set of output NAL units and their
order are both identical. Optimizations relative to the described order are both identical. Optimizations relative to the described
algorithms are possible. algorithms are possible.
All normal RTP mechanisms related to buffer management apply. In All normal RTP mechanisms related to buffer management apply. In
particular, duplicated or outdated RTP packets (as indicated by the particular, duplicated or outdated RTP packets (as indicated by the
RTP sequence number and the RTP timestamp) are removed. To determine RTP sequence number and the RTP timestamp) are removed. To determine
the exact time for decoding, factors such as a possible intentional the exact time for decoding, factors, such as a possible intentional
delay to allow for proper inter-stream synchronization MUST be delay to allow for proper inter-stream synchronization, MUST be
factored in. factored in.
NAL units with NAL unit type values in the range of 0 to 27, NAL units with NAL unit type values in the range of 0 to 27,
inclusive, may be passed to the decoder. NAL-unit-like structures inclusive, may be passed to the decoder. NAL-unit-like structures
with NAL unit type values in the range of 28 to 31, inclusive, MUST with NAL unit type values in the range of 28 to 31, inclusive, MUST
NOT be passed to the decoder. NOT be passed to the decoder.
The receiver includes a receiver buffer, which is used to compensate The receiver includes a receiver buffer, which is used to compensate
for transmission delay jitter within individual RTP stream, and to for transmission delay jitter within individual RTP streams and to
reorder NAL units from transmission order to the NAL unit decoding reorder NAL units from transmission order to the NAL unit decoding
order. In this section, the receiver operation is described under order. In this section, the receiver operation is described under
the assumption that there is no transmission delay jitter within an the assumption that there is no transmission delay jitter within an
RTP stream. To make a difference from a practical receiver buffer RTP stream. To make a difference from a practical receiver buffer
that is also used for compensation of transmission delay jitter, the that is also used for compensation of transmission delay jitter, the
receiver buffer is hereafter called the de-packetization buffer in receiver buffer is hereafter called the de-packetization buffer in
this section. Receivers should also prepare for transmission delay this section. Receivers should also prepare for transmission delay
jitter; that is, either reserve separate buffers for transmission jitter, that is, either reserve separate buffers for transmission
delay jitter buffering and de-packetization buffering or use a delay jitter buffering and de-packetization buffering or use a
receiver buffer for both transmission delay jitter and de- receiver buffer for both transmission delay jitter and de-
packetization. Moreover, receivers should take transmission delay packetization. Moreover, receivers should take transmission delay
jitter into account in the buffering operation, e.g., by additional jitter into account in the buffering operation, e.g., by additional
initial buffering before starting of decoding and playback. initial buffering before starting of decoding and playback.
The de-packetization process extracts the NAL units from the RTP The de-packetization process extracts the NAL units from the RTP
packets in an RTP stream as follows. When an RTP packet carries a packets in an RTP stream as follows. When an RTP packet carries a
single NAL unit packet, the payload of the RTP packet is extracted as single NAL unit packet, the payload of the RTP packet is extracted as
a single NAL unit, excluding the DONL field, i.e., third and fourth a single NAL unit, excluding the DONL field, i.e., third and fourth
bytes, when sprop-max-don-diff is greater than 0. When an RTP packet bytes, when sprop-max-don-diff is greater than 0. When an RTP packet
carries an Aggregation Packet, several NAL units are extracted from carries an aggregation packet, several NAL units are extracted from
the payload of the RTP packet. In this case, each NAL unit the payload of the RTP packet. In this case, each NAL unit
corresponds to the part of the payload of each aggregation unit that corresponds to the part of the payload of each aggregation unit that
follows the NALU size field as described in Section 4.3.2. When an follows the NALU size field, as described in Section 4.3.2. When an
RTP packet carries a Fragmentation Unit (FU), all RTP packets from RTP packet carries a Fragmentation Unit (FU), all RTP packets from
the first FU (with the S field equal to 1) of the fragmented NAL unit the first FU (with the S field equal to 1) of the fragmented NAL unit
up to the last FU (with the E field equal to 1) of the fragmented NAL up to the last FU (with the E field equal to 1) of the fragmented NAL
unit are collected. The NAL unit is extracted from these RTP packets unit are collected. The NAL unit is extracted from these RTP packets
by concatenating all FU payloads in the same order as the by concatenating all FU payloads in the same order as the
corresponding RTP packets and appending the NAL unit header with the corresponding RTP packets and appending the NAL unit header with the
fields F, LayerId, and TID, set to equal to the values of the fields fields F, LayerId, and TID set to equal the values of the fields F,
F, LayerId, and TID in the payload header of the FUs respectively, LayerId, and TID in the payload header of the FUs, respectively, and
and with the NAL unit type set equal to the value of the field FuType with the NAL unit type set equal to the value of the field FuType in
in the FU header of the FUs, as described in Section 4.3.3. the FU header of the FUs, as described in Section 4.3.3.
When sprop-max-don-diff is equal to 0, the de-packetization buffer When sprop-max-don-diff is equal to 0, the de-packetization buffer
size is zero bytes, and the NAL units carried in the single RTP size is zero bytes, and the NAL units carried in the single RTP
stream are directly passed to the decoder in their transmission stream are directly passed to the decoder in their transmission
order, which is identical to their decoding order. order, which is identical to their decoding order.
When sprop-max-don-diff is greater than 0, the process described in When sprop-max-don-diff is greater than 0, the process described in
the remainder of this section applies. the remainder of this section applies.
There are two buffering states in the receiver: initial buffering and There are two buffering states in the receiver: initial buffering and
skipping to change at page 35, line 47 skipping to change at line 1598
Initial buffering lasts until the difference between the greatest and Initial buffering lasts until the difference between the greatest and
smallest AbsDon values of the NAL units in the de-packetization smallest AbsDon values of the NAL units in the de-packetization
buffer is greater than or equal to the value of sprop-max-don-diff. buffer is greater than or equal to the value of sprop-max-don-diff.
After initial buffering, whenever the difference between the greatest After initial buffering, whenever the difference between the greatest
and smallest AbsDon values of the NAL units in the de-packetization and smallest AbsDon values of the NAL units in the de-packetization
buffer is greater than or equal to the value of sprop-max-don-diff, buffer is greater than or equal to the value of sprop-max-don-diff,
the following operation is repeatedly applied until this difference the following operation is repeatedly applied until this difference
is smaller than sprop-max-don-diff: is smaller than sprop-max-don-diff:
* The NAL unit in the de-packetization buffer with the smallest The NAL unit in the de-packetization buffer with the smallest
value of AbsDon is removed from the de-packetization buffer and value of AbsDon is removed from the de-packetization buffer and
passed to the decoder. passed to the decoder.
When no more NAL units are flowing into the de-packetization buffer, When no more NAL units are flowing into the de-packetization buffer,
all NAL units remaining in the de-packetization buffer are removed all NAL units remaining in the de-packetization buffer are removed
from the buffer and passed to the decoder in the order of increasing from the buffer and passed to the decoder in the order of increasing
AbsDon values. AbsDon values.
7. Payload Format Parameters 7. Payload Format Parameters
This section specifies the optional parameters. A mapping of the This section specifies the optional parameters. A mapping of the
parameters with Session Description Protocol (SDP) [RFC4556] is also parameters with Session Description Protocol (SDP) [RFC8866] is also
provided for applications that use SDP. provided for applications that use SDP.
Parameters starting with the string "sprop" for stream properties can Parameters starting with the string "sprop" for stream properties can
be used by a sender to provide a receiver with the properties of the be used by a sender to provide a receiver with the properties of the
stream that is or will be sent. The media sender (and not the stream that is or will be sent. The media sender (and not the
receiver) selects whether, and with what values, "sprop" parameters receiver) selects whether, and with what values, "sprop" parameters
are being sent. This uncommon characteristic of the "sprop" are being sent. This uncommon characteristic of the "sprop"
parameters may not be intuitive in the context of some signaling parameters may not be intuitive in the context of some signaling
protocol concepts, especially with offer/answer. Please see protocol concepts, especially with offer/answer. Please see
Section 7.3.2 for guidance specific to the use of sprop parameters in Section 7.3.2 for guidance specific to the use of sprop parameters in
the Offer/Answer case. the offer/answer case.
7.1. Media Type Registration 7.1. Media Type Registration
The receiver MUST ignore any parameter unspecified in this memo. The receiver MUST ignore any parameter unspecified in this memo.
Type name: video Type name: video
Subtype name: H266 Subtype name: H266
Required parameters: N/A Required parameters: N/A
Optional parameters: Optional parameters: profile-id, tier-flag, sub-profile-id, interop-
constraints, level-id, sprop-sublayer-id, sprop-ols-id, recv-
profile-id, tier-flag, sub-profile-id, interop-constraints, level- sublayer-id, recv-ols-id, max-recv-level-id, sprop-dci, sprop-vps,
id, sprop-sublayer-id, sprop-ols-id, recv-sublayer-id, recv-ols- sprop-sps, sprop-pps, sprop-sei, max-lsr, max-fps, sprop-max-don-
id, max-recv-level-id, sprop-dci, sprop-vps, sprop-sps, sprop-pps, diff, sprop-depack-buf-bytes, depack-buf-cap (refer to Section 7.2
sprop-sei, max-lsr, max-fps, sprop-max-don-diff, sprop-depack-buf- for definitions).
bytes, depack-buf-cap (Refer to Section 7.2 for definitions).
Encoding considerations:
This type is only defined for transfer via RTP (RFC 3550).
Security considerations:
See Section 9 of RFC XXXX. Encoding considerations: This type is only defined for transfer via
RTP [RFC3550].
Interoperability considerations: N/A Security considerations: See Section 9 of RFC 9328.
Published specification:
Please refer to RFC XXXX and VVC coding specification [VVC]. Interoperability considerations: N/A
Applications that use this media type: Published specification: Please refer to RFC 9328 and VVC coding
specification [VVC].
Any application that relies on VVC-based video services over RTP Applications that use this media type: Any application that relies
on VVC-based video services over RTP
Fragment identifier considerations: N/A Fragment identifier considerations: N/A
Additional information: N/A Additional information: N/A
Person & email address to contact for further information: Person & email address to contact for further information:
Stephan Wenger (stewe@stewe.org) Stephan Wenger (stewe@stewe.org)
Intended usage: COMMON Intended usage: COMMON
Restrictions on usage: N/A
Author: See Authors' Addresses section of RFC XXXX. Restrictions on usage: N/A
Change controller: Author: See Authors' Addresses section of RFC 9328.
IETF <avtcore@ietf.org> Change controller: IETF <avtcore@ietf.org>
7.2. Optional Parameters Definition 7.2. Optional Parameters Definition
profile-id, tier-flag, sub-profile-id, interop-constraints, and profile-id, tier-flag, sub-profile-id, interop-constraints, and
level-id: level-id:
These parameters indicate the profile, the tier, the default
These parameters indicate the profile, tier, default level, sub- level, the sub-profile, and some constraints of the bitstream
profile, and some constraints of the bitstream carried by the RTP carried by the RTP stream, or a specific set of the profile, the
stream, or a specific set of the profile, tier, default level, tier, the default level, the sub-profile, and some constraints the
sub-profile and some constraints the receiver supports. receiver supports.
The subset of coding tools that may have been used to generate the The subset of coding tools that may have been used to generate the
bitstream or that the receiver supports, as well as some bitstream or that the receiver supports, as well as some
additional constraints are indicated collectively by profile-id, additional constraints, are indicated collectively by profile-id,
sub-profile-id, and interop-constraints. sub-profile-id, and interop-constraints.
Informative note: There are 128 values of profile-id. The | Informative note: There are 128 values of profile-id. The
subset of coding tools identified by the profile-id can be | subset of coding tools identified by profile-id can be
further constrained with up to 255 instances of sub-profile-id. | further constrained with up to 255 instances of sub-profile-
In addition, 68 bits included in interop-constraints, which can | id. In addition, 68 bits included in interop-constraints,
be extended up to 324 bits provide means to further restrict | which can be extended up to 324 bits, provide means to
tools from existing profiles. To be able to support this fine- | further restrict tools from existing profiles. To be able
granular signaling of coding tool subsets with profile-id, sub- | to support this fine-granular signaling of coding-tool
profile-id and interop-constraints, it would be safe to require | subsets with profile-id, sub-profile-id, and interop-
symmetric use of these parameters in SDP offer/answer unless | constraints, it would be safe to require symmetric use of
recv-ols-id is included in the SDP answer for choosing one of | these parameters in SDP offer/answer unless recv-ols-id is
the layers offered. | included in the SDP answer for choosing one of the layers
| offered.
The tier is indicated by tier-flag. The default level is The tier is indicated by tier-flag. The default level is
indicated by level-id. The tier and the default level specify the indicated by level-id. The tier and the default level specify the
limits on values of syntax elements or arithmetic combinations of limits on values of syntax elements or arithmetic combinations of
values of syntax elements that are followed when generating the values of syntax elements that are followed when generating the
bitstream or that the receiver supports. bitstream or that the receiver supports.
In SDP offer/answer, when the SDP answer does not include the In SDP offer/answer, when the SDP answer does not include the
recv-ols-id parameter that is less than the sprop-ols-id parameter recv-ols-id parameter that is less than the sprop-ols-id parameter
in the SDP offer, the following applies: in the SDP offer, the following applies:
- The tier-flag, profile-id, sub-profile-id, and interop- * The tier-flag, profile-id, sub-profile-id, and interop-
constraints parameters MUST be used symmetrically, i.e., the constraints parameters MUST be used symmetrically, i.e., the
value of each of these parameters in the offer MUST be the same value of each of these parameters in the offer MUST be the same
as that in the answer, either explicitly signaled or implicitly as that in the answer, either explicitly signaled or implicitly
inferred. inferred.
- The level-id parameter is changeable as long as the highest * The level-id parameter is changeable as long as the highest
level indicated by the answer is either equal to or lower than level indicated by the answer is either equal to or lower than
that in the offer. Note that a highest level higher than that in the offer. Note that the highest level higher than
level-id in the offer for receiving can be included as max- level-id in the offer for receiving can be included as max-
recv-level-id. recv-level-id.
In SDP offer/answer, when the SDP answer does include the recv- In SDP offer/answer, when the SDP answer does include the recv-
ols-id parameter that is less than the sprop-ols-id parameter ols-id parameter that is less than the sprop-ols-id parameter in
in the SDP offer, the set of tier-flag, profile-id, sub- the SDP offer, the set of tier-flag, profile-id, sub-profile-id,
profile-id, interop-constraints, and level-id parameters interop-constraints, and level-id parameters included in the
included in the answer MUST be consistent with that for the answer MUST be consistent with that for the chosen output layer
chosen output layer set as indicated in the SDP offer, with the set as indicated in the SDP offer, with the exception that the
exception that the level-id parameter in the SDP answer is level-id parameter in the SDP answer is changeable as long as the
changeable as long as the highest level indicated by the answer highest level indicated by the answer is either lower than or
is either lower than or equal to that in the offer. equal to that in the offer.
More specifications of these parameters, including how they relate More specifications of these parameters, including how they relate
to syntax elements specified in [VVC] are provided below. to syntax elements specified in [VVC], are provided below.
profile-id: profile-id:
When profile-id is not present, a value of 1 (i.e., the Main 10 When profile-id is not present, a value of 1 (i.e., the Main 10
profile) MUST be inferred. profile) MUST be inferred.
When used to indicate properties of a bitstream, profile-id is When used to indicate properties of a bitstream, profile-id is
derived from the general_profile_idc syntax element that applies derived from the general_profile_idc syntax element that applies
to the bitstream in an instance of the profile_tier_level( ) to the bitstream in an instance of the profile_tier_level( )
syntax structure. syntax structure.
VVC bitstreams transported over RTP using the technologies of this VVC bitstreams transported over RTP using the technologies of this
memo SHOULD contain only a single profile_tier_level( ) structure memo SHOULD contain only a single profile_tier_level( ) structure
in the DCI, unless the sender can assure that a receiver can in the DCI, unless the sender can assure that a receiver can
correctly decode the VVC bitstream regardless of which correctly decode the VVC bitstream, regardless of which
profile_tier_level( ) structure contained in the DCI was used for profile_tier_level( ) structure contained in the DCI was used for
deriving profile-id and other parameters for the SDP O/A exchange. deriving profile-id and other parameters for the SDP offer/answer
exchange.
As specified in [VVC], a profile_tier_level( ) syntax structure As specified in [VVC], a profile_tier_level( ) syntax structure
may be contained in an SPS NAL unit, and one or more may be contained in an SPS NAL unit, and one or more
profile_tier_level( ) syntax structures may be contained in a VPS profile_tier_level( ) syntax structures may be contained in a VPS
NAL unit and in a DCI NAL unit. One of the following three cases NAL unit and in a DCI NAL unit. One of the following three cases
applies to the container NAL unit of the profile_tier_level( ) applies to the container NAL unit of the profile_tier_level( )
syntax structure containing syntax elements used to derive the syntax structure containing syntax elements used to derive the
values of profile-id, tier-flag, level-id, sub-profile-id, or values of profile-id, tier-flag, level-id, sub-profile-id, or
interop-constraints: 1) The container NAL unit is an SPS, the interop-constraints:
bitstream is a single-layer bitstream, and the profile_tier_level(
) syntax structures in all SPSs referenced by the CVSs in the 1. The container NAL unit is an SPS, the bitstream is a single-
bitstream has the same values respectively for those layer bitstream, and the profile_tier_level( ) syntax
profile_tier_level( ) syntax elements; 2) The container NAL unit structures in all SPSs referenced by the CVSs in the bitstream
is a VPS, the profile_tier_level( ) syntax structure is the one in have the same values respectively for those
the VPS that applies to the OLS corresponding to the bitstream, profile_tier_level( ) syntax elements.
and the profile_tier_level( ) syntax structures applicable to the
OLS corresponding to the bitstream in all VPSs referenced by the 2. The container NAL unit is a VPS, the profile_tier_level( )
CVSs in the bitstream have the same values respectively for those syntax structure is the one in the VPS that applies to the OLS
profile_tier_level( ) syntax elements; 3) The container NAL unit corresponding to the bitstream, and the profile_tier_level( )
is a DCI NAL unit and the profile_tier_level( ) syntax structures syntax structures applicable to the OLS corresponding to the
in all DCI NAL units in the bitstream has the same values bitstream in all VPSs referenced by the CVSs in the bitstream
respectively for those profile_tier_level( ) syntax elements. have the same values respectively for those
profile_tier_level( ) syntax elements.
3. The container NAL unit is a DCI NAL unit, and the
profile_tier_level( ) syntax structures in all DCI NAL units
in the bitstream have the same values respectively for those
profile_tier_level( ) syntax elements.
[VVC] allows for multiple profile_tier_level( ) structures in a [VVC] allows for multiple profile_tier_level( ) structures in a
DCI NAL unit, which may contain different values for the syntax DCI NAL unit, which may contain different values for the syntax
elements used to derive the values of profile-id, tier-flag, elements used to derive the values of profile-id, tier-flag,
level-id, sub-profile-id, or interop-constraints in the different level-id, sub-profile-id, or interop-constraints in the different
entries. However, herein defined is only a single profile-id, entries. However, herein defined is only a single profile-id,
tier-flag, level-id, sub-profile-id, or interop-constraints. When tier-flag, level-id, sub-profile-id, or interop-constraints. When
signaling these parameters and a DCI NAL unit is present with signaling these parameters and a DCI NAL unit is present with
multiple profile_tier_level( ) structures, these values SHOULD be multiple profile_tier_level( ) structures, these values SHOULD be
the same as the first profile_tier_level structure in the DCI, the same as the first profile_tier_level structure in the DCI,
skipping to change at page 40, line 4 skipping to change at line 1789
level-id, sub-profile-id, or interop-constraints in the different level-id, sub-profile-id, or interop-constraints in the different
entries. However, herein defined is only a single profile-id, entries. However, herein defined is only a single profile-id,
tier-flag, level-id, sub-profile-id, or interop-constraints. When tier-flag, level-id, sub-profile-id, or interop-constraints. When
signaling these parameters and a DCI NAL unit is present with signaling these parameters and a DCI NAL unit is present with
multiple profile_tier_level( ) structures, these values SHOULD be multiple profile_tier_level( ) structures, these values SHOULD be
the same as the first profile_tier_level structure in the DCI, the same as the first profile_tier_level structure in the DCI,
unless the sender has ensured that the receiver can decode the unless the sender has ensured that the receiver can decode the
bitstream when a different value is chosen. bitstream when a different value is chosen.
tier-flag, level-id: tier-flag, level-id:
The value of tier-flag MUST be in the range of 0 to 1, inclusive. The value of tier-flag MUST be in the range of 0 to 1, inclusive.
The value of level-id MUST be in the range of 0 to 255, inclusive. The value of level-id MUST be in the range of 0 to 255, inclusive.
If the tier-flag and level-id parameters are used to indicate If the tier-flag and level-id parameters are used to indicate
properties of a bitstream, they indicate the tier and the highest properties of a bitstream, they indicate the tier and the highest
level the bitstream complies with. level the bitstream complies with.
If the tier-flag and level-id parameters are used for capability If the tier-flag and level-id parameters are used for capability
exchange, the following applies. If max-recv-level-id is not exchange, the following applies. If max-recv-level-id is not
present, the default level defined by level-id indicates the present, the default level defined by level-id indicates the
highest level the codec wishes to support. Otherwise, max-recv- highest level the codec wishes to support. Otherwise, max-recv-
level-id indicates the highest level the codec supports for level-id indicates the highest level the codec supports for
receiving. For either receiving or sending, all levels that are receiving. For either receiving or sending, all levels that are
lower than the highest level supported MUST also be supported. lower than the highest level supported MUST also be supported.
If no tier-flag is present, a value of 0 MUST be inferred; if no If no tier-flag is present, a value of 0 MUST be inferred; if no
level-id is present, a value of 51 (i.e., level 3.1) MUST be level-id is present, a value of 51 (i.e., level 3.1) MUST be
inferred. inferred.
Informative note: The level values currently defined in the VVC | Informative note: The level values currently defined in the
specification are in the form of "majorNum.minorNum", and the | VVC specification are in the form of "majorNum.minorNum",
value of the level-id for each of the levels is equal to | and the value of the level-id for each of the levels is
majorNum * 16 + minorNum * 3. It is expected that if any | equal to majorNum * 16 + minorNum * 3. It is expected that,
levels are defined in the future, the same convention will be | if any levels are defined in the future, the same convention
used, but this cannot be guaranteed. | will be used, but this cannot be guaranteed.
When used to indicate properties of a bitstream, the tier-flag and When used to indicate properties of a bitstream, the tier-flag and
level-id parameters are derived respectively from the syntax level-id parameters are derived respectively from the syntax
element general_tier_flag, and the syntax element element general_tier_flag, and the syntax element
general_level_idc or sub_layer_level_idc[j], that apply to the general_level_idc or sub_layer_level_idc[j], that apply to the
bitstream, in an instance of the profile_tier_level( ) syntax bitstream in an instance of the profile_tier_level( ) syntax
structure. structure.
If the tier-flag and level-id are derived from the If the tier-flag and level-id are derived from the
profile_tier_level( ) syntax structure in a DCI NAL unit, the profile_tier_level( ) syntax structure in a DCI NAL unit, the
following applies: following applies:
- tier-flag = general_tier_flag * tier-flag = general_tier_flag
- level-id = general_level_idc * level-id = general_level_idc
Otherwise, if the tier-flag and level-id are derived from the Otherwise, if the tier-flag and level-id are derived from the
profile_tier_level( ) syntax structure in an SPS or VPS NAL unit, profile_tier_level( ) syntax structure in an SPS or VPS NAL unit,
and the bitstream contains the highest sublayer representation in and the bitstream contains the highest sublayer representation in
the OLS corresponding to the bitstream, the following applies: the OLS corresponding to the bitstream, the following applies:
- tier-flag = general_tier_flag * tier-flag = general_tier_flag
- level-id = general_level_idc
* level-id = general_level_idc
Otherwise, if the tier-flag and level-id are derived from the Otherwise, if the tier-flag and level-id are derived from the
profile_tier_level( ) syntax structure in an SPS or VPS NAL profile_tier_level( ) syntax structure in an SPS or VPS NAL unit,
unit, and the bitstream does not contain the highest sublayer and the bitstream does not contain the highest sublayer
representation in the OLS corresponding to the bitstream, the representation in the OLS corresponding to the bitstream, the
following applies, with j being the value of the sprop- following applies, with j being the value of the sprop-sublayer-id
sublayer-id parameter: parameter:
- tier-flag = general_tier_flag * tier-flag = general_tier_flag
- level-id = sub_layer_level_idc[j] * level-id = sub_layer_level_idc[j]
sub-profile-id: sub-profile-id:
The value of the parameter is a comma-separated (',') list of data The value of the parameter is a comma-separated (',') list of data
using base64 encoding (Section 4 of [RFC4648]) representation using base64 encoding (Section 4 of [RFC4648]) representation
without "==" padding. without "==" padding.
When used to indicate properties of a bitstream, sub-profile-id is When used to indicate properties of a bitstream, sub-profile-id is
derived from each of the ptl_num_sub_profiles derived from each of the ptl_num_sub_profiles
general_sub_profile_idc[i] syntax elements that apply to the general_sub_profile_idc[i] syntax elements that apply to the
bitstream in a profile_tier_level( ) syntax structure. bitstream in a profile_tier_level( ) syntax structure.
interop-constraints: interop-constraints:
skipping to change at page 41, line 29 skipping to change at line 1861
The value of the parameter is a comma-separated (',') list of data The value of the parameter is a comma-separated (',') list of data
using base64 encoding (Section 4 of [RFC4648]) representation using base64 encoding (Section 4 of [RFC4648]) representation
without "==" padding. without "==" padding.
When used to indicate properties of a bitstream, sub-profile-id is When used to indicate properties of a bitstream, sub-profile-id is
derived from each of the ptl_num_sub_profiles derived from each of the ptl_num_sub_profiles
general_sub_profile_idc[i] syntax elements that apply to the general_sub_profile_idc[i] syntax elements that apply to the
bitstream in a profile_tier_level( ) syntax structure. bitstream in a profile_tier_level( ) syntax structure.
interop-constraints: interop-constraints:
A base64 encoding (Section 4 of [RFC4648]) representation of the A base64 encoding (Section 4 of [RFC4648]) representation of the
data that includes the syntax elements data that includes the ptl_frame_only_constraint_flag syntax
ptl_frame_only_constraint_flag and ptl_multilayer_enabled_flag and element, the ptl_multilayer_enabled_flag syntax element, and the
the general_constraints_info( ) syntax structure that apply to the general_constraints_info( ) syntax structure that apply to the
bitstream in an instance of the profile_tier_level( ) syntax bitstream in an instance of the profile_tier_level( ) syntax
structure. structure.
If the interop-constraints parameter is not present, the following If the interop-constraints parameter is not present, the following
MUST be inferred: MUST be inferred:
- ptl_frame_only_constraint_flag = 1 * ptl_frame_only_constraint_flag = 1
- ptl_multilayer_enabled_flag = 0 * ptl_multilayer_enabled_flag = 0
- gci_present_flag in the general_constraints_info( ) syntax * gci_present_flag in the general_constraints_info( ) syntax
structure = 0 structure = 0
Using interop-constraints for capability exchange results in a Using interop-constraints for capability exchange results in a
requirement on any bitstream to be compliant with the interop- requirement on any bitstream to be compliant with the interop-
constraints. constraints.
sprop-sublayer-id: sprop-sublayer-id:
This parameter MAY be used to indicate the highest allowed value This parameter MAY be used to indicate the highest allowed value
of TID in the bitstream. When not present, the value of sprop- of TID in the bitstream. When not present, the value of sprop-
sublayer-id is inferred to be equal to 6. sublayer-id is inferred to be equal to 6.
The value of sprop-sublayer-id MUST be in the range of 0 to 6, The value of sprop-sublayer-id MUST be in the range of 0 to 6,
inclusive. inclusive.
sprop-ols-id: sprop-ols-id:
This parameter MAY be used to indicate the OLS that the bitstream This parameter MAY be used to indicate the OLS that the bitstream
applies to. When not present, the value of sprop-ols-id is applies to. When not present, the value of sprop-ols-id is
inferred to be equal to TargetOlsIdx as specified in 8.1.1 in inferred to be equal to TargetOlsIdx, as specified in
[VVC]. If this optional parameter is present, sprop-vps MUST also Section 8.1.1 of [VVC]. If this optional parameter is present,
be present or its content MUST be known a priori at the receiver. sprop-vps MUST also be present or its content MUST be known a
priori at the receiver.
The value of sprop-ols-id MUST be in the range of 0 to 256, The value of sprop-ols-id MUST be in the range of 0 to 256,
inclusive. inclusive.
Informative note: VVC allows having up to 257 output layer sets | Informative note: VVC allows having up to 257 output layer
indicated in the VPS as the number of output layer sets minus 2 | sets indicated in the VPS, as the number of output layer
is indicated with a field of 8 bits. | sets minus 2 is indicated with a field of 8 bits.
recv-sublayer-id: recv-sublayer-id:
This parameter MAY be used to signal a receiver's choice of the This parameter MAY be used to signal a receiver's choice of the
offered or declared sublayer representations in the sprop-vps and offered or declared sublayer representations in sprop-vps and
sprop-sps. The value of recv-sublayer-id indicates the TID of the sprop-sps. The value of recv-sublayer-id indicates the TID of the
highest sublayer that a receiver supports. When not present, the highest sublayer that a receiver supports. When not present, the
value of recv-sublayer-id is inferred to be equal to the value of value of recv-sublayer-id is inferred to be equal to the value of
the sprop-sublayer-id parameter in the SDP offer. the sprop-sublayer-id parameter in the SDP offer.
The value of recv-sublayer-id MUST be in the range of 0 to 6, The value of recv-sublayer-id MUST be in the range of 0 to 6,
inclusive. inclusive.
recv-ols-id: recv-ols-id:
This parameter MAY be used to signal a receiver's choice of the This parameter MAY be used to signal a receiver's choice of the
offered or declared output layer sets in the sprop-vps. The value offered or declared output layer sets in sprop-vps. The value of
of recv-ols-id indicates the OLS index of the bitstream that a recv-ols-id indicates the OLS index of the bitstream that a
receiver supports. When not present, the value of recv-ols-id is receiver supports. When not present, the value of recv-ols-id is
inferred to be equal to value of the sprop-ols-id parameter inferred to be equal to the value of the sprop-ols-id parameter
inferred from or indicated in the SDP offer. When present, the inferred from or indicated in the SDP offer. When present, the
value of recv-ols-id must be included only when sprop-ols-id was value of recv-ols-id must be included only when sprop-ols-id was
received and must refer to an output layer set in the VPS that received and must refer to an output layer set in the VPS that
includes no layers other than all or a subset of the layers of the includes no layers other than all or a subset of the layers of the
OLS referred to by sprop-ols-id. If this optional parameter is OLS referred to by sprop-ols-id. If this optional parameter is
present, sprop-vps must have been received or its content must be present, sprop-vps must have been received or its content must be
known a priori at the receiver. known a priori at the receiver.
The value of recv-ols-id MUST be in the range of 0 to 256, The value of recv-ols-id MUST be in the range of 0 to 256,
inclusive. inclusive.
skipping to change at page 43, line 23 skipping to change at line 1947
The value of max-recv-level-id MUST be in the range of 0 to 255, The value of max-recv-level-id MUST be in the range of 0 to 255,
inclusive. inclusive.
When max-recv-level-id is not present, the value is inferred to be When max-recv-level-id is not present, the value is inferred to be
equal to level-id. equal to level-id.
max-recv-level-id MUST NOT be present when the highest level the max-recv-level-id MUST NOT be present when the highest level the
receiver supports is not higher than the default level. receiver supports is not higher than the default level.
sprop-dci: sprop-dci:
This parameter MAY be used to convey a decoding capability This parameter MAY be used to convey a decoding capability
information NAL unit of the bitstream for out-of-band information NAL unit of the bitstream for out-of-band
transmission. The parameter MAY also be used for capability transmission. The parameter MAY also be used for capability
exchange. The value of the parameter a base64 encoding (Section 4 exchange. The value of the parameter is a base64 encoding
of [RFC4648]) representations of the decoding capability (Section 4 of [RFC4648]) representation of the decoding capability
information NAL unit as specified in Section 7.3.2.1 of [VVC]. information NAL unit, as specified in Section 7.3.2.1 of [VVC].
sprop-vps: sprop-vps:
This parameter MAY be used to convey any video parameter set to
This parameter MAY be used to convey any video parameter set NAL the NAL unit of the bitstream for out-of-band transmission of
unit of the bitstream for out-of-band transmission of video video parameter sets. The parameter MAY also be used for
parameter sets. The parameter MAY also be used for capability capability exchange and to indicate substream characteristics
exchange and to indicate sub-stream characteristics (i.e., (i.e., properties of output layer sets and sublayer
properties of output layer sets and sublayer representations as representations, as defined in [VVC]). The value of the parameter
defined in [VVC]). The value of the parameter is a comma- is a comma-separated (',') list of base64 encoding (Section 4 of
separated (',') list of base64 encoding (Section 4 of [RFC4648]) [RFC4648]) representations of the video parameter set NAL units,
representations of the video parameter set NAL units as specified as specified in Section 7.3.2.3 of [VVC].
in Section 7.3.2.3 of [VVC].
The sprop-vps parameter MAY contain one or more than one video The sprop-vps parameter MAY contain one or more than one video
parameter set NAL units. However, all other video parameter sets parameter set NAL units. However, all other video parameter sets
contained in the sprop-vps parameter MUST be consistent with the contained in the sprop-vps parameter MUST be consistent with the
first video parameter set in the sprop-vps parameter. A video first video parameter set in the sprop-vps parameter. A video
parameter set vpsB is said to be consistent with another video parameter set vpsB is said to be consistent with another video
parameter set vpsA if the number of OLSs in vpsA and vpsB is the parameter set vpsA if the number of OLSs in vpsA and vpsB are the
same and any decoder that conforms to the profile, tier, level, same and any decoder that conforms to the profile, tier, level,
and constraints indicated by the data starting from the syntax and constraints indicated by the data starting from the syntax
element general_profile_idc to the syntax structure element general_profile_idc to the syntax structure
general_constraints_info(), inclusive, in the profile_tier_level( general_constraints_info(), inclusive, in the profile_tier_level(
) syntax structure corresponding to any OLS with index olsIdx in ) syntax structure corresponding to any OLS with index olsIdx in
vpsA can decode any CVS(s) referencing vpsB when TargetOlsIdx is vpsA can decode any CVS(s) referencing vpsB when TargetOlsIdx is
equal to olsIdx that conforms to the profile, tier, level, and equal to olsIdx that conforms to the profile, tier, level, and
constraints indicated by the data starting from the syntax element constraints indicated by the data starting from the syntax element
general_profile_idc to the syntax structure general_profile_idc to the syntax structure
general_constraints_info(), inclusive, in the profile_tier_level( general_constraints_info(), inclusive, in the profile_tier_level(
skipping to change at page 44, line 14 skipping to change at line 1985
) syntax structure corresponding to any OLS with index olsIdx in ) syntax structure corresponding to any OLS with index olsIdx in
vpsA can decode any CVS(s) referencing vpsB when TargetOlsIdx is vpsA can decode any CVS(s) referencing vpsB when TargetOlsIdx is
equal to olsIdx that conforms to the profile, tier, level, and equal to olsIdx that conforms to the profile, tier, level, and
constraints indicated by the data starting from the syntax element constraints indicated by the data starting from the syntax element
general_profile_idc to the syntax structure general_profile_idc to the syntax structure
general_constraints_info(), inclusive, in the profile_tier_level( general_constraints_info(), inclusive, in the profile_tier_level(
) syntax structure corresponding to the OLS with index ) syntax structure corresponding to the OLS with index
TargetOlsIdx in vpsB. TargetOlsIdx in vpsB.
sprop-sps: sprop-sps:
This parameter MAY be used to convey sequence parameter set NAL This parameter MAY be used to convey sequence parameter set NAL
units of the bitstream for out-of-band transmission of sequence units of the bitstream for out-of-band transmission of sequence
parameter sets. The value of the parameter is a comma-separated parameter sets. The value of the parameter is a comma-separated
(',') list of base64 encoding (Section 4 of [RFC4648]) (',') list of base64 encoding (Section 4 of [RFC4648])
representations of the sequence parameter set NAL units as representations of the sequence parameter set NAL units, as
specified in Section 7.3.2.4 of [VVC]. specified in Section 7.3.2.4 of [VVC].
A sequence parameter set spsB is said to be consistent with A sequence parameter set spsB is said to be consistent with
another sequence parameter set spsA if any decoder that conforms another sequence parameter set spsA if any decoder that conforms
to the profile, tier, level, and constraints indicated by the data to the profile, tier, level, and constraints indicated by the data
starting from the syntax element general_profile_idc to the syntax starting from the syntax element general_profile_idc to the syntax
structure general_constraints_info(), inclusive, in the structure general_constraints_info(), inclusive, in the
profile_tier_level( ) syntax structure in spsA can decode any profile_tier_level( ) syntax structure in spsA can decode any
CLVS(s) referencing spsB that conforms to the profile, tier, CLVS(s) referencing spsB that conforms to the profile, tier,
level, and constraints indicated by the data starting from the level, and constraints indicated by the data starting from the
skipping to change at page 44, line 35 skipping to change at line 2005
starting from the syntax element general_profile_idc to the syntax starting from the syntax element general_profile_idc to the syntax
structure general_constraints_info(), inclusive, in the structure general_constraints_info(), inclusive, in the
profile_tier_level( ) syntax structure in spsA can decode any profile_tier_level( ) syntax structure in spsA can decode any
CLVS(s) referencing spsB that conforms to the profile, tier, CLVS(s) referencing spsB that conforms to the profile, tier,
level, and constraints indicated by the data starting from the level, and constraints indicated by the data starting from the
syntax element general_profile_idc to the syntax structure syntax element general_profile_idc to the syntax structure
general_constraints_info(), inclusive, in the profile_tier_level( general_constraints_info(), inclusive, in the profile_tier_level(
) syntax structure in spsB. ) syntax structure in spsB.
sprop-pps: sprop-pps:
This parameter MAY be used to convey picture parameter set NAL This parameter MAY be used to convey picture parameter set NAL
units of the bitstream for out-of-band transmission of picture units of the bitstream for out-of-band transmission of picture
parameter sets. The value of the parameter is a comma-separated parameter sets. The value of the parameter is a comma-separated
(',') list of base64 encoding (Section 4 of [RFC4648]) (',') list of base64 encoding (Section 4 of [RFC4648])
representations of the picture parameter set NAL units as representations of the picture parameter set NAL units, as
specified in Section 7.3.2.5 of [VVC]. specified in Section 7.3.2.5 of [VVC].
sprop-sei: sprop-sei:
This parameter MAY be used to convey one or more SEI messages that This parameter MAY be used to convey one or more SEI messages that
describe bitstream characteristics. When present, a decoder can describe bitstream characteristics. When present, a decoder can
rely on the bitstream characteristics that are described in the rely on the bitstream characteristics that are described in the
SEI messages for the entire duration of the session, independently SEI messages for the entire duration of the session, independently
from the persistence scopes of the SEI messages as specified in from the persistence scopes of the SEI messages, as specified in
[VSEI]. [VSEI].
The value of the parameter is a comma-separated (',') list of The value of the parameter is a comma-separated (',') list of
base64 encoding (Section 4 of [RFC4648]) representations of SEI base64 encoding (Section 4 of [RFC4648]) representations of SEI
NAL units as specified in [VSEI]. NAL units, as specified in [VSEI].
Informative note: Intentionally, no list of applicable or
inapplicable SEI messages is specified here. Conveying certain
SEI messages in sprop-sei may be sensible in some application
scenarios and meaningless in others. However, a few examples
are described below:
1) In an environment where the bitstream was created from film-
based source material, and no splicing is going to occur during
the lifetime of the session, the film grain characteristics SEI
message is likely meaningful, and sending it in sprop-sei
rather than in the bitstream at each entry point may help with
saving bits and allows one to configure the renderer only once,
avoiding unwanted artifacts.
2) Examples for SEI messages that would be meaningless to be | Informative note: Intentionally, no list of applicable or
conveyed in sprop-sei include the decoded picture hash SEI | inapplicable SEI messages is specified here. Conveying
message (it is close to impossible that all decoded pictures | certain SEI messages in sprop-sei may be sensible in some
have the same hashtag) or the filler payload SEI message (as | application scenarios and meaningless in others. However, a
there is no point in just having more bits in SDP). | few examples are described below:
|
| In an environment where the bitstream was created from film-
| based source material, and no splicing is going to occur
| during the lifetime of the session, the film grain
| characteristics SEI message is likely meaningful, and
| sending it in sprop-sei, rather than in the bitstream at
| each entry point, may help with saving bits and allows one
| to configure the renderer only once, avoiding unwanted
| artifacts.
|
| Examples for SEI messages that would be meaningless to be
| conveyed in sprop-sei include the decoded picture hash SEI
| message (it is close to impossible that all decoded pictures
| have the same hashtag) or the filler payload SEI message (as
| there is no point in just having more bits in SDP).
max-lsr: max-lsr:
The max-lsr MAY be used to signal the capabilities of a receiver The max-lsr MAY be used to signal the capabilities of a receiver
implementation and MUST NOT be used for any other purpose. The implementation and MUST NOT be used for any other purpose. The
value of max-lsr is an integer indicating the maximum processing value of max-lsr is an integer indicating the maximum processing
rate in units of luma samples per second. The max-lsr parameter rate in units of luma samples per second. The max-lsr parameter
signals that the receiver is capable of decoding video at a higher signals that the receiver is capable of decoding video at a higher
rate than is required by the highest level. rate than is required by the highest level.
Informative note: When the OPTIONAL media type parameters are | Informative note: When the OPTIONAL media type parameters
used to signal the properties of a bitstream, and max-lsr is | are used to signal the properties of a bitstream, and max-
not present, the values of tier-flag, profile-id, sub-profile- | lsr is not present, the values of tier-flag, profile-id,
id interop-constraints, and level-id must always be such that | sub-profile-id, interop-constraints, and level-id must
the bitstream complies fully with the specified profile, tier, | always be such that the bitstream complies fully with the
and level. | specified profile, sub-profile, tier, level, and interop-
| constraints.
When max-lsr is signaled, the receiver MUST be able to decode When max-lsr is signaled, the receiver MUST be able to decode
bitstreams that conform to the highest level, with the exception bitstreams that conform to the highest level, with the exception
that the MaxLumaSr value in Table 136 of [VVC] for the highest that the MaxLumaSr value in Table A.3 of [VVC] for the highest
level is replaced with the value of max-lsr. Senders MAY use this level is replaced with the value of max-lsr. Senders MAY use this
knowledge to send pictures of a given size at a higher picture knowledge to send pictures of a given size at a higher picture
rate than is indicated in the highest level. rate than is indicated in the highest level.
When not present, the value of max-lsr is inferred to be equal to When not present, the value of max-lsr is inferred to be equal to
the value of MaxLumaSr given in Table 136 of [VVC] for the highest the value of MaxLumaSr given in Table A.3 of [VVC] for the highest
level. level.
The value of max-lsr MUST be in the range of MaxLumaSr to 16 * The value of max-lsr MUST be in the range of MaxLumaSr to 16 *
MaxLumaSr, inclusive, where MaxLumaSr is given in Table 136 of MaxLumaSr, inclusive, where MaxLumaSr is given in Table A.3 of
[VVC] for the highest level. [VVC] for the highest level.
max-fps: max-fps:
The value of max-fps is an integer indicating the maximum picture The value of max-fps is an integer indicating the maximum picture
rate in units of pictures per 100 seconds that can be effectively rate in units of pictures per 100 seconds that can be effectively
processed by the receiver. The max-fps parameter MAY be used to processed by the receiver. The max-fps parameter MAY be used to
signal that the receiver has a constraint in that it is not signal that the receiver has a constraint in that it is not
capable of processing video effectively at the full picture rate capable of processing video effectively at the full picture rate
that is implied by the highest level and, when present, max-lsr. that is implied by the highest level and, when present, max-lsr.
The value of max-fps is not necessarily the picture rate at which The value of max-fps is not necessarily the picture rate at which
the maximum picture size can be sent, it constitutes a constraint the maximum picture size can be sent; it constitutes a constraint
on maximum picture rate for all resolutions. on maximum picture rate for all resolutions.
Informative note: The max-fps parameter is semantically | Informative note: The max-fps parameter is semantically
different from max-lsr in that max-fps is used to signal a | different from max-lsr in that max-fps is used to signal a
constraint, lowering the maximum picture rate from what is | constraint, lowering the maximum picture rate from what is
implied by other parameters. | implied by other parameters.
The encoder MUST use a picture rate equal to or less than this The encoder MUST use a picture rate equal to or less than this
value. In cases where the max-fps parameter is absent, the value. In cases where the max-fps parameter is absent, the
encoder is free to choose any picture rate according to the encoder is free to choose any picture rate according to the
highest level and any signaled optional parameters. highest level and any signaled optional parameters.
The value of max-fps MUST be smaller than or equal to the full The value of max-fps MUST be smaller than or equal to the full
picture rate that is implied by the highest level and, when picture rate that is implied by the highest level and, when
present, max-lsr. present, max-lsr.
skipping to change at page 47, line 12 skipping to change at line 2120
of any two NAL units naluA and naluB, where naluA follows naluB in of any two NAL units naluA and naluB, where naluA follows naluB in
decoding order and precedes naluB in transmission order. decoding order and precedes naluB in transmission order.
The value of sprop-max-don-diff MUST be an integer in the range of The value of sprop-max-don-diff MUST be an integer in the range of
0 to 32767, inclusive. 0 to 32767, inclusive.
When not present, the value of sprop-max-don-diff is inferred to When not present, the value of sprop-max-don-diff is inferred to
be equal to 0. be equal to 0.
sprop-depack-buf-bytes: sprop-depack-buf-bytes:
This parameter signals the required size of the de-packetization This parameter signals the required size of the de-packetization
buffer in units of bytes. The value of the parameter MUST be buffer in units of bytes. The value of the parameter MUST be
greater than or equal to the maximum buffer occupancy (in units of greater than or equal to the maximum buffer occupancy (in units of
bytes) of the de-packetization buffer as specified in Section 6. bytes) of the de-packetization buffer, as specified in Section 6.
The value of sprop-depack-buf-bytes MUST be an integer in the The value of sprop-depack-buf-bytes MUST be an integer in the
range of 0 to 4294967295, inclusive. range of 0 to 4294967295, inclusive.
When sprop-max-don-diff is present and greater than 0, this When sprop-max-don-diff is present and greater than 0, this
parameter MUST be present and the value MUST be greater than 0. parameter MUST be present and the value MUST be greater than 0.
When not present, the value of sprop-depack-buf-bytes is inferred When not present, the value of sprop-depack-buf-bytes is inferred
to be equal to 0. to be equal to 0.
Informative note: The value of sprop-depack-buf-bytes indicates | Informative note: The value of sprop-depack-buf-bytes
the required size of the de-packetization buffer only. When | indicates the required size of the de-packetization buffer
network jitter can occur, an appropriately sized jitter buffer | only. When network jitter can occur, an appropriately sized
has to be available as well. | jitter buffer has to be available as well.
depack-buf-cap: depack-buf-cap:
This parameter signals the capabilities of a receiver This parameter signals the capabilities of a receiver
implementation and indicates the amount of de-packetization buffer implementation and indicates the amount of de-packetization buffer
space in units of bytes that the receiver has available for space in units of bytes that the receiver has available for
reconstructing the NAL unit decoding order from NAL units carried reconstructing the NAL unit decoding order from NAL units carried
in the RTP stream. A receiver is able to handle any RTP stream in the RTP stream. A receiver is able to handle any RTP stream
for which the value of the sprop-depack-buf-bytes parameter is for which the value of the sprop-depack-buf-bytes parameter is
smaller than or equal to this parameter. smaller than or equal to this parameter.
When not present, the value of depack-buf-cap is inferred to be When not present, the value of depack-buf-cap is inferred to be
equal to 4294967295. The value of depack-buf-cap MUST be an equal to 4294967295. The value of depack-buf-cap MUST be an
integer in the range of 1 to 4294967295, inclusive. integer in the range of 1 to 4294967295, inclusive.
Informative note: depack-buf-cap indicates the maximum possible | Informative note: depack-buf-cap indicates the maximum
size of the de-packetization buffer of the receiver only, | possible size of the de-packetization buffer of the receiver
without allowing for network jitter. | only, without allowing for network jitter.
7.3. SDP Parameters 7.3. SDP Parameters
The receiver MUST ignore any parameter unspecified in this memo. The receiver MUST ignore any parameter unspecified in this memo.
7.3.1. Mapping of Payload Type Parameters to SDP 7.3.1. Mapping of Payload Type Parameters to SDP
The media type video/H266 string is mapped to fields in the Session The media type video/H266 string is mapped to fields in the Session
Description Protocol (SDP) [RFC8866] as follows: Description Protocol (SDP) [RFC8866] as follows:
* The media name in the "m=" line of SDP MUST be video. * The media name in the "m=" line of SDP MUST be video.
* The encoding name in the "a=rtpmap" line of SDP MUST be H266 (the * The encoding name in the "a=rtpmap" line of SDP MUST be H266 (the
media subtype). media subtype).
* The clock rate in the "a=rtpmap" line MUST be 90000. * The clock rate in the "a=rtpmap" line MUST be 90000.
* The OPTIONAL parameters profile-id, tier-flag, sub-profile-id, * The OPTIONAL parameters profile-id, tier-flag, sub-profile-id,
interop-constraints, level-id, sprop-sublayer-id, sprop-ols-id, interop-constraints, level-id, sprop-sublayer-id, sprop-ols-id,
recv-sublayer-id, recv-ols-id, max-recv-level-id, max-lsr, max- recv-sublayer-id, recv-ols-id, max-recv-level-id, max-lsr, max-
fps, sprop-max-don-diff, sprop-depack-buf-bytes and depack-buf- fps, sprop-max-don-diff, sprop-depack-buf-bytes, and depack-buf-
cap, when present, MUST be included in the "a=fmtp" line of SDP. cap, when present, MUST be included in the "a=fmtp" line of SDP.
The fmtp line is expressed as a media type string, in the form of The fmtp line is expressed as a media type string, in the form of
a semicolon-separated list of parameter=value pairs. a semicolon-separated list of parameter=value pairs.
* The OPTIONAL parameter sprop-vps, sprop-sps, sprop-pps, sprop-sei, * The OPTIONAL parameters sprop-vps, sprop-sps, sprop-pps, sprop-
and sprop-dci, when present, MUST be included in the "a=fmtp" line sei, and sprop-dci, when present, MUST be included in the "a=fmtp"
of SDP or conveyed using the "fmtp" source attribute as specified line of SDP or conveyed using the "fmtp" source attribute as
in Section 6.3 of [RFC5576]. For a particular media format (i.e., specified in Section 6.3 of [RFC5576]. For a particular media
RTP payload type), sprop-vps, sprop-sps, sprop-pps, sprop-sei, or format (i.e., RTP payload type), sprop-vps, sprop-sps, sprop-pps,
sprop-dci MUST NOT be both included in the "a=fmtp" line of SDP sprop-sei, or sprop-dci MUST NOT be both included in the "a=fmtp"
and conveyed using the "fmtp" source attribute. When included in line of SDP and conveyed using the "fmtp" source attribute. When
the "a=fmtp" line of SDP, those parameters are expressed as a included in the "a=fmtp" line of SDP, those parameters are
media type string, in the form of a semicolon-separated list of expressed as a media type string, in the form of a semicolon-
parameter=value pairs. When conveyed in the "a=fmtp" line of SDP separated list of parameter=value pairs. When conveyed in the
for a particular payload type, the parameters sprop-vps, sprop- "a=fmtp" line of SDP for a particular payload type, the parameters
sps, sprop-pps, sprop-sei, and sprop-dci MUST be applied to each sprop-vps, sprop-sps, sprop-pps, sprop-sei, and sprop-dci MUST be
SSRC with the payload type. When conveyed using the "fmtp" source applied to each SSRC with the payload type. When conveyed using
attribute, these parameters are only associated with the given the "fmtp" source attribute, these parameters are only associated
source and payload type as parts of the "fmtp" source attribute. with the given source and payload type as parts of the "fmtp"
source attribute.
Informative note: Conveyance of sprop-vps, sprop-sps, and | Informative note: Conveyance of sprop-vps, sprop-sps, and
sprop-pps using the "fmtp" source attribute allows for out-of- | sprop-pps using the "fmtp" source attribute allows for out-of-
band transport of parameter sets in topologies like Topo-Video- | band transport of parameter sets in topologies like Topo-Video-
switch-MCU as specified in [RFC7667] | switch-MCU, as specified in [RFC7667].
An general usage of media representation in SDP is as follows: A general usage of media representation in SDP is as follows:
m=video 49170 RTP/AVP 98 m=video 49170 RTP/AVP 98
a=rtpmap:98 H266/90000 a=rtpmap:98 H266/90000
a=fmtp:98 profile-id=1; a=fmtp:98 profile-id=1;
sprop-vps=<video parameter sets data>; sprop-vps=<video parameter sets data>;
sprop-sps=<sequence parameter set data>; sprop-sps=<sequence parameter set data>;
sprop-pps=<picture parameter set data>; sprop-pps=<picture parameter set data>;
A SIP Offer/Answer exchange wherein both parties are expected to both A SIP offer/answer exchange wherein both parties are expected to both
send and receive could look like the following. Only the media send and receive could look like the following. Only the media
codec-specific parts of the SDP are shown. Some lines are wrapped codec-specific parts of the SDP are shown. Some lines are wrapped
due to text constraints. due to text constraints.
Offerer->Answerer: Offerer->Answerer:
m=video 49170 RTP/AVP 98 m=video 49170 RTP/AVP 98
a=rtpmap:98 H266/90000 a=rtpmap:98 H266/90000
a=fmtp:98 profile-id=1; level_id=83; a=fmtp:98 profile-id=1; level_id=83;
The above represents an offer for symmetric video communication using The above represents an offer for symmetric video communication using
[VVC] and it's payload specification, at the main profile and level [VVC] and its payload specification at the main profile and level 5.1
5.1 (and, as the levels are downgradable, all lower levels. (and as the levels are downgradable, all lower levels). Informally
Informally speaking, this offer tells the receiver of the offer that speaking, this offer tells the receiver of the offer that the sender
the sender is willing to receive up to 4Kp60 resolution at the is willing to receive up to 4Kp60 resolution at the maximum bitrates
maximum bitrates specified in [VVC]. At the same time, if this offer specified in [VVC]. At the same time, if this offer were accepted
were accepted "as is", the offer can expect that the answerer would "as is", the offer can expect that the answerer would be able to
be able to receive and properly decode H.266 media up to and receive and properly decode H.266 media up to and including level
including level 5.1. 5.1.
Answerer->Offerer: Answerer->Offerer:
m=video 49170 RTP/AVP 98 m=video 49170 RTP/AVP 98
a=rtpmap:98 H266/90000 a=rtpmap:98 H266/90000
a=fmtp:98 profile-id=1; level_id=67 a=fmtp:98 profile-id=1; level_id=67
With this answer to the offer above, the system receiving the offer With this answer to the offer above, the system receiving the offer
advises the offerer that it is incapable of handing H.266 at level advises the offerer that it is incapable of handing H.266 at level
5.1 but is capable of decoding 1080p60. As H.266 video codecs must 5.1 but is capable of decoding 1080p60. As H.266 video codecs must
support decoding at all levels below the maximum level they support decoding at all levels below the maximum level they
implement, the resulting user experience would likely be that both implement, the resulting user experience would likely be that both
systems send video at 1080p60. However, nothing prevents an encoder systems send video at 1080p60. However, nothing prevents an encoder
from further downgrading its sending to, for example 720p30 if it from further downgrading its sending to, for example, 720p30 if it
were short of cycles, bandwidth, or for other reasons. were short of cycles or bandwidth or for other reasons.
7.3.2. Usage with SDP Offer/Answer Model 7.3.2. Usage with SDP Offer/Answer Model
This section describes the negotiation of unicast messages using the This section describes the negotiation of unicast messages using the
offer-answer model as described in [RFC3264] and its updates. The offer/answer model as described in [RFC3264] and its updates. The
section is split into subsections, covering a) media format section is split into subsections, covering a) media format
configurations not involving non-temporal scalability; b) scalable configurations not involving non-temporal scalability; b) scalable
media format configurations; c) the description of the use of those media format configurations; c) the description of the use of those
parameters not involving the media configuration itself but rather parameters not involving the media configuration itself but rather
the parameters of the payload format design; and d) multicast. the parameters of the payload format design; and d) multicast.
7.3.2.1. Non-scalable media format configuration 7.3.2.1. Non-scalable Media Format Configuration
A non-scalable VVC media configuration is such a configuration where A non-scalable VVC media configuration is such a configuration where
no non-temporal scalability mechanisms are allowed. In [VVC] version no non-temporal scalability mechanisms are allowed. In [VVC] version
1, that implies that general_profile_idc indicates one of the 1, it is implied that general_profile_idc indicates one of the
following profiles: Main10, Main10 Still Picture, Main 10 4:4:4, following profiles: Main 10, Main 10 Still Picture, Main 10 4:4:4, or
Main10 4:4:4 Still Picture, with general_profile_idc values of 1, 65, Main 10 4:4:4 Still Picture, with general_profile_idc values of 1,
33, and 97, respectively. Note that non-scalable media 65, 33, and 97, respectively. Note that non-scalable media
configurations includes temporal scalability, inline with VVC's configurations include temporal scalability inline with VVC's design
design philosophy and profile structure. philosophy and profile structure.
The following limitations and rules pertaining to the media The following limitations and rules pertaining to the media
configuration apply: configuration apply:
* The parameters identifying a media format configuration for VVC * The parameters identifying a media format configuration for VVC
are profile-id, tier-flag, sub-profile-id, level-id, and interop- are profile-id, tier-flag, sub-profile-id, level-id, and interop-
constraints. These media configuration parameters, except level- constraints. These media configuration parameters, except level-
id, MUST be used symmetrically. id, MUST be used symmetrically.
The answerer MUST structure its answer in according to one of the The answerer MUST structure its answer according to one of the
following three options: following three options:
1) maintain all configuration parameters with the values remaining 1. maintain all configuration parameters with the values
the same as in the offer for the media format (payload type), with remaining the same as in the offer for the media format
the exception that the value of level-id is changeable as long as (payload type), with the exception that the value of level-id
the highest level indicated by the answer is not higher than that is changeable as long as the highest level indicated by the
indicated by the offer; answer is not higher than that indicated by the offer;
2) include in the answer the recv-sublayer-id parameter, with a 2. include in the answer the recv-sublayer-id parameter, with a
value less than the sprop-sublayer-id parameter in the offer, for value less than the sprop-sublayer-id parameter in the offer,
the media format (payload type), and maintain all configuration for the media format (payload type), and maintain all
parameters with the values remaining the same as in the offer for configuration parameters with the values remaining the same as
the media format (payload type), with the exception that the value in the offer for the media format (payload type), with the
of level-id is changeable as long as the highest level indicated exception that the value of level-id is changeable as long as
by the answer is not higher than the level indicated by the sprop- the highest level indicated by the answer is not higher than
sps or sprop-vps in offer for the chosen sublayer representation; the level indicated by sprop-sps or sprop-vps in offer for the
or chosen sublayer representation; or
3) remove the media format (payload type) completely (when one or
more of the parameter values are not supported).
Informative note: The above requirement for symmetric use 3. remove the media format (payload type) completely (when one or
does not apply for level-id, and does not apply for the more of the parameter values are not supported).
other bitstream or RTP stream properties and capability
parameters as described in Section 7.3.2.3 below. | Informative note: The above requirement for symmetric use does
| not apply for level-id and does not apply for the other
| bitstream or RTP stream properties and capability parameters,
| as described in Section 7.3.2.3 below.
* To simplify handling and matching of these configurations, the * To simplify handling and matching of these configurations, the
same RTP payload type number used in the offer SHOULD also be used same RTP payload type number used in the offer SHOULD also be used
in the answer, as specified in [RFC3264]. in the answer, as specified in [RFC3264].
* The same RTP payload type number used in the offer for the media * The same RTP payload type number used in the offer for the media
subtype H266 MUST be used in the answer when the answer includes subtype H266 MUST be used in the answer when the answer includes
recv-sublayer-id. When the answer does not include recv-sublayer- recv-sublayer-id. When the answer does not include recv-sublayer-
id, the answer MUST NOT contain a payload type number used in the id, the answer MUST NOT contain a payload type number used in the
offer for the media subtype H266 unless the configuration is offer for the media subtype H266 unless the configuration is
exactly the same as in the offer or the configuration in the exactly the same as in the offer or the configuration in the
answer only differs from that in the offer with a different value answer only differs from that in the offer with a different value
of level-id. The answer MAY contain the recv-sublayer-id of level-id. The answer MAY contain the recv-sublayer-id
parameter if an VVC bitstream contains multiple operation points parameter if a VVC bitstream contains multiple operation points
(using temporal scalability and sublayers) and sprop-sps or sprop- (using temporal scalability and sublayers) and sprop-sps or sprop-
vps is included in the offer where information of sublayers are vps is included in the offer where information of sublayers are
present in the first sequence parameter set or video parameter set present in the first sequence parameter set or video parameter set
contained in sprop-sps or sprop-vps respectively. If the sprop- contained in sprop-sps or sprop-vps, respectively. If sprop-sps
sps or sprop-vps is provided in an offer, an answerer MAY select a or sprop-vps is provided in an offer, an answerer MAY select a
particular operation point indicated in the first sequence particular operation point indicated in the first sequence
parameter set or video parameter set contained in sprop-sps or parameter set or video parameter set contained in sprop-sps or
sprop-vps respectively. When the answer includes a recv-sublayer- sprop-vps, respectively. When the answer includes a recv-
id that is less than a sprop-sublayer-id in the offer, the sublayer-id that is less than a sprop-sublayer-id in the offer,
following applies: the following applies:
1) When sprop-sps parameter is present, all sequence parameter 1. When the sprop-sps parameter is present, all sequence
sets contained in the sprop-sps parameter in the SDP answer and parameter sets contained in the sprop-sps parameter in the SDP
all sequence parameter sets sent in-band for either the offerer- answer and all sequence parameter sets sent in-band for either
to-answerer direction or the answerer-to-offerer direction MUST be the offerer-to-answerer direction or the answerer-to-offerer
consistent with the first sequence parameter set in the sprop-sps direction MUST be consistent with the first sequence parameter
parameter of the offer (see the semantics of sprop-sps in set in the sprop-sps parameter of the offer (see the semantics
Section 7.1 of this document on one sequence parameter set being of sprop-sps in Section 7.1 of this document on one sequence
consistent with another sequence parameter set). parameter set being consistent with another sequence parameter
set).
2) When sprop-vps parameter is present, all video parameter sets 2. When the sprop-vps parameter is present, all video parameter
contained in the sprop-vps parameter in the SDP answer and all sets contained in the sprop-vps parameter in the SDP answer
video parameter sets sent in-band for either the offerer-to- and all video parameter sets sent in-band for either the
answerer direction or the answerer-to-offerer direction MUST be offerer-to-answerer direction or the answerer-to-offerer
consistent with the first video parameter set in the sprop-vps direction MUST be consistent with the first video parameter
parameter of the offer (see the semantics of sprop-vps in set in the sprop-vps parameter of the offer (see the semantics
Section 7.1 of this document on one video parameter set being of sprop-vps in Section 7.1 of this document on one video
consistent with another video parameter set). parameter set being consistent with another video parameter
set).
3) The bitstream sent in either direction MUST conform to the 3. The bitstream sent in either direction MUST conform to the
profile, tier, level, and constraints of the chosen sublayer profile, tier, level, and constraints of the chosen sublayer
representation as indicated by the profile_tier_level( ) syntax representation, as indicated by the profile_tier_level( )
structure in the first sequence parameter set in the sprop-sps syntax structure in the first sequence parameter set in the
parameter or by the first profile_tier_level( ) syntax structure sprop-sps parameter or by the first profile_tier_level( )
in the first video parameter set in the sprop-vps parameter of the syntax structure in the first video parameter set in the
offer. sprop-vps parameter of the offer.
Informative note: When an offerer receives an answer that | Informative note: When an offerer receives an answer that does
does not include recv-sublayer-id, it has to compare payload | not include recv-sublayer-id, it has to compare payload types
types not declared in the offer based on the media type | not declared in the offer based on the media type (i.e., video/
(i.e., video/H266) and the above media configuration | H266) and the above media configuration parameters with any
parameters with any payload types it has already declared. | payload types it has already declared. This will enable it to
This will enable it to determine whether the configuration | determine whether the configuration in question is new or if it
in question is new or if it is equivalent to configuration | is equivalent to configuration already offered, since a
already offered, since a different payload type number may | different payload type number may be used in the answer. The
be used in the answer. The ability to perform operation | ability to perform operation point selection enables a receiver
point selection enables a receiver to utilize the temporal | to utilize the temporal scalable nature of a VVC bitstream.
scalable nature of an VVC bitstream.
7.3.2.2. Scalable media format configuration 7.3.2.2. Scalable Media Format Configuration
A scalable VVC media configuration is such a configuration where non- A scalable VVC media configuration is such a configuration where non-
temporal scalability mechanisms are allowed. In [VVC] version 1, temporal scalability mechanisms are allowed. In [VVC] version 1, it
that implies that general_profile_idc indicates one of the following is implied that general_profile_idc indicates one of the following
profiles: Multilayer Main 10, and Multilayer Main 10 4:4:4, with profiles: Multilayer Main 10 and Multilayer Main 10 4:4:4, with
general_profile_idc values of 17 and 49, respectively. general_profile_idc values of 17 and 49, respectively.
The following limitations and rules pertaining to the media The following limitations and rules pertaining to the media
configuration apply. They are listed in an order that would be configuration apply. They are listed in an order that would be
logical for an implementation to follow: logical for an implementation to follow:
* The parameters identifying a media format configuration for * The parameters identifying a media format configuration for
scalable VVC are profile-id, tier-flag, sub-profile-id, level-id, scalable VVC are profile-id, tier-flag, sub-profile-id, level-id,
interop-constraints, and sprop-vps. These media configuration interop-constraints, and sprop-vps. These media configuration
parameters, except level-id, MUST be used symmetrically, except as parameters, except level-id, MUST be used symmetrically, except as
noted below. noted below.
* The answerer MAY include a level-id that MUST be lower than or * The answerer MAY include a level-id that MUST be lower than or
equal to the level-id indicated in the offer (either expressed by equal to the level-id indicated in the offer (either expressed by
level-id in the offer, or implied by the default level as specific level-id in the offer or implied by the default level, as
in Section 7.1). specified in Section 7.1).
* When sprop-ols-id is present in an offer, sprop-vps MUST also be * When sprop-ols-id is present in an offer, sprop-vps MUST also be
present in the same offer and including at least one valid VPS, so present in the same offer and include at least one valid VPS so to
to allow the answerer to meaningfully interpret sprop-ols-id and allow the answerer to meaningfully interpret sprop-ols-id and
select recv-ols-id (see below). select recv-ols-id (see below).
* The answerer MUST NOT include recv-ols-id unless the offer * The answerer MUST NOT include recv-ols-id unless the offer
includes sprop-ols-id. When present, recv-ols-id MUST indicate a includes sprop-ols-id. When present, recv-ols-id MUST indicate a
supported output layer set in the VPS that includes no layers supported output layer set in the VPS that includes no layers
other than all or a subset of the layers of the OLS referred to by other than all or a subset of the layers of the OLS referred to by
sprop-ols-id. If unable, the answerer MUST remove the media sprop-ols-id. If unable, the answerer MUST remove the media
format. format.
Informative note: if an offerer wants to offer more than one | Informative note: If an offerer wants to offer more than one
output layer set, it can do so by offering multiple VVC media | output layer set, it can do so by offering multiple VVC media
with different payload types. | with different payload types.
* The offerer MAY include sprop-sublayer-id which indicates the * The offerer MAY include sprop-sublayer-id, which indicates the
highest allowed value of TID in the bitstream. The answerer MAY highest allowed value of TID in the bitstream. The answerer MAY
include recv-sublayer-id which can be used to reduce the number of include recv-sublayer-id, which can be used to reduce the number
sublayers from the value of sprop-sublayer-id. of sublayers from the value of sprop-sublayer-id.
* When the answerer includes recv-ols-id and configuration * When the answerer includes recv-ols-id and configuration
parameters profile-id, tier-flag, sub-profile-id, level-id, and parameters profile-id, tier-flag, sub-profile-id, level-id, and
interop-constraints, it MUST use the configuration parameter interop-constraints, it MUST use the configuration parameter
values as signaled in the sprop-vps for the operating point with values as signaled in the sprop-vps for the operating point with
the largest number of sublayers for the chosen output layer set, the largest number of sublayers for the chosen output layer set,
with the exception that the value of level-id is changeable as with the exception that the value of level-id is changeable as
long as the highest level indicated by the answer is not higher long as the highest level indicated by the answer is not higher
than the level indicated by the sprop-vps in offer for the than the level indicated by sprop-vps in offer for the operating
operating point with the largest number of sublayers for the point with the largest number of sublayers for the chosen output
chosen output layer set. layer set.
7.3.2.3. Payload format configuration 7.3.2.3. Payload Format Configuration
The following limitations and rules pertain to the configuration of The following limitations and rules pertain to the configuration of
the payload format buffer management mostly and apply to both the payload format buffer management mostly and apply to both
scalable and non-scalable VVC. scalable and non-scalable VVC.
* The parameters sprop-max-don-diff, and sprop-depack-buf-bytes * The parameters sprop-max-don-diff and sprop-depack-buf-bytes
describe the properties of an RTP stream that the offerer or the describe the properties of an RTP stream that the offerer or the
answerer is sending for the media format configuration. This answerer is sending for the media format configuration. This
differs from the normal usage of the offer/answer parameters: differs from the normal usage of the offer/answer parameters;
normally such parameters declare the properties of the bitstream normally, such parameters declare the properties of the bitstream
or RTP stream that the offerer or the answerer is able to receive. or RTP stream that the offerer or the answerer is able to receive.
When dealing with VVC, the offerer assumes that the answerer will When dealing with VVC, the offerer assumes that the answerer will
be able to receive media encoded using the configuration being be able to receive media encoded using the configuration being
offered. offered.
Informative note: The above parameters apply for any RTP | Informative note: The above parameters apply for any RTP
stream, when present, sent by a declaring entity with the same | stream, when present, sent by a declaring entity with the same
configuration. In other words, the applicability of the above | configuration. In other words, the applicability of the above
parameters to RTP streams depends on the source endpoint. | parameters to RTP streams depends on the source endpoint.
Rather than being bound to the payload type, the values may | Rather than being bound to the payload type, the values may
have to be applied to another payload type when being sent, as | have to be applied to another payload type when being sent, as
they apply for the configuration. | they apply for the configuration.
* The capability parameter max-lsr MAY be used to declare further * The capability parameter max-lsr MAY be used to declare further
capabilities of the offerer or answerer for receiving. It MUST capabilities of the offerer or answerer for receiving. It MUST
NOT be present when the direction attribute is sendonly. NOT be present when the direction attribute is sendonly.
* The capability parameter max-fps MAY be used to declare lower * The capability parameter max-fps MAY be used to declare lower
capabilities of the offerer or answerer for receiving. It MUST capabilities of the offerer or answerer for receiving. It MUST
NOT be present when the direction attribute is sendonly. NOT be present when the direction attribute is sendonly.
* When an offerer offers an interleaved stream, indicated by the * When an offerer offers an interleaved stream, indicated by the
presence of sprop-max-don-diff with a value larger than zero, the presence of sprop-max-don-diff with a value larger than zero, the
offerer MUST include the size of the de-packetization buffer offerer MUST include the size of the de-packetization buffer
sprop-depack-buf-bytes. sprop-depack-buf-bytes.
* To enable the offerer and answerer to inform each other about * To enable the offerer and answerer to inform each other about
their capabilities for de-packetization buffering in receiving RTP their capabilities for de-packetization buffering in receiving RTP
streams, both parties are RECOMMENDED to include depack-buf-cap. streams, both parties are RECOMMENDED to include depack-buf-cap.
* The sprop-dci, sprop-vps, sprop-sps, or sprop-pps, when present * The parameters sprop-dci, sprop-vps, sprop-sps, or sprop-pps, when
(included in the "a=fmtp" line of SDP or conveyed using the "fmtp" present (included in the "a=fmtp" line of SDP or conveyed using
source attribute as specified in Section 6.3 of [RFC5576]), are the "fmtp" source attribute, as specified in Section 6.3 of
used for out-of-band transport of the parameter sets (DCI, VPS, [RFC5576]), are used for out-of-band transport of the parameter
SPS, or PPS, respectively). sets (DCI, VPS, SPS, or PPS, respectively).
* The answerer MAY use either out-of-band or in-band transport of * The answerer MAY use either out-of-band or in-band transport of
parameter sets for the bitstream it is sending, regardless of parameter sets for the bitstream it is sending, regardless of
whether out-of-band parameter sets transport has been used in the whether out-of-band parameter sets transport has been used in the
offerer-to-answerer direction. Parameter sets included in an offerer-to-answerer direction. Parameter sets included in an
answer are independent of those parameter sets included in the answer are independent of those parameter sets included in the
offer, as they are used for decoding two different bitstreams, one offer, as they are used for decoding two different bitstreams; one
from the answerer to the offerer and the other in the opposit from the answerer to the offerer and the other in the opposite
direction. In case some RTP packets are sent before the SDP direction. In case some RTP packets are sent before the SDP
offer/answer settles down, in-band parameter sets MUST be used for offer/answer settles down, in-band parameter sets MUST be used for
those RTP stream parts sent before the SDP offer/answer. those RTP stream parts sent before the SDP offer/answer.
* The following rules apply to transport of parameter set in the * The following rules apply to transport of parameter sets in the
offerer-to-answerer direction. offerer-to-answerer direction.
- An offer MAY include sprop-dci, sprop-vps, sprop-sps, and/or - An offer MAY include sprop-dci, sprop-vps, sprop-sps, and/or
sprop-pps. If none of these parameters is present in the sprop-pps. If none of these parameters are present in the
offer, then only in-band transport of parameter sets is used. offer, then only in-band transport of parameter sets is used.
- If the level to use in the offerer-to-answerer direction is - If the level to use in the offerer-to-answerer direction is
equal to the default level in the offer, the answerer MUST be equal to the default level in the offer, the answerer MUST be
prepared to use the parameter sets included in sprop-vps, prepared to use the parameter sets included in sprop-vps,
sprop-sps, and sprop-pps (either included in the "a=fmtp" line sprop-sps, and sprop-pps (either included in the "a=fmtp" line
of SDP or conveyed using the "fmtp" source attribute) for of SDP or conveyed using the "fmtp" source attribute) for
decoding the incoming bitstream, e.g., by passing these decoding the incoming bitstream, e.g., by passing these
parameter set NAL units to the video decoder before passing any parameter set NAL units to the video decoder before passing any
NAL units carried in the RTP streams. Otherwise, the answerer NAL units carried in the RTP streams. Otherwise, the answerer
MUST ignore sprop-vps, sprop-sps, and sprop-pps (either MUST ignore sprop-vps, sprop-sps, and sprop-pps (either
included in the "a=fmtp" line of SDP or conveyed using the included in the "a=fmtp" line of SDP or conveyed using the
"fmtp" source attribute) and the offerer MUST transmit "fmtp" source attribute) and the offerer MUST transmit
parameter sets in-band. parameter sets in-band.
* The following rules apply to transport of parameter set in the * The following rules apply to transport of parameter sets in the
answerer-to-offerer direction. answerer-to-offerer direction.
- An answer MAY include sprop-dci, sprop-vps, sprop-sps, and/or - An answer MAY include sprop-dci, sprop-vps, sprop-sps, and/or
sprop-pps. If none of these parameters is present in the sprop-pps. If none of these parameters are present in the
answer, then only in-band transport of parameter sets is used. answer, then only in-band transport of parameter sets is used.
- The offerer MUST be prepared to use the parameter sets included - The offerer MUST be prepared to use the parameter sets included
in sprop-vps, sprop-sps, and sprop-pps (either included in the in sprop-vps, sprop-sps, and sprop-pps (either included in the
"a=fmtp" line of SDP or conveyed using the "fmtp" source "a=fmtp" line of SDP or conveyed using the "fmtp" source
attribute) for decoding the incoming bitstream, e.g., by attribute) for decoding the incoming bitstream, e.g., by
passing these parameter set NAL units to the video decoder passing these parameter set NAL units to the video decoder
before passing any NAL units carried in the RTP streams. before passing any NAL units carried in the RTP streams.
* When sprop-dci, sprop-vps, sprop-sps, and/or sprop-pps are * When sprop-dci, sprop-vps, sprop-sps, and/or sprop-pps are
conveyed using the "fmtp" source attribute as specified in conveyed using the "fmtp" source attribute, as specified in
Section 6.3 of [RFC5576], the receiver of the parameters MUST Section 6.3 of [RFC5576], the receiver of the parameters MUST
store the parameter sets included in sprop-dci, sprop-vps, sprop- store the parameter sets included in sprop-dci, sprop-vps, sprop-
sps, and/or sprop-pps and associate them with the source given as sps, and/or sprop-pps and associate them with the source given as
part of the "fmtp" source attribute. Parameter sets associated part of the "fmtp" source attribute. Parameter sets associated
with one source (given as part of the "fmtp" source attribute) with one source (given as part of the "fmtp" source attribute)
MUST only be used to decode NAL units conveyed in RTP packets from MUST only be used to decode NAL units conveyed in RTP packets from
the same source (given as part of the "fmtp" source attribute). the same source (given as part of the "fmtp" source attribute).
When this mechanism is in use, SSRC collision detection and When this mechanism is in use, SSRC collision detection and
resolution MUST be performed as specified in [RFC5576]. resolution MUST be performed as specified in [RFC5576].
Table 1 lists the interpretation of all the parameters that MAY be Figure 11 lists the interpretation of all the parameters that MAY be
used for the various combinations of offer, answer, and direction used for the various combinations of offer, answer, and direction
attributes. Note that the two columns wherein the recv-ols-id attributes.
parameter is used only apply to answers, whereas the other columns
apply to both offers and answers.
sendonly --+ sendonly --+
answer: recvonly, recv-ols-id --+ | answer: recvonly, recv-ols-id --+ |
recvonly w/o recv-ols-id --+ | | recvonly w/o recv-ols-id --+ | |
answer: sendrecv, recv-ols-id --+ | | | answer: sendrecv, recv-ols-id --+ | | |
sendrecv w/o recv-ols-id --+ | | | | sendrecv w/o recv-ols-id --+ | | | |
| | | | | | | | | |
profile-id C D C D P profile-id C D C D P
tier-flag C D C D P tier-flag C D C D P
level-id D D D D P level-id D D D D P
skipping to change at page 57, line 32 skipping to change at line 2553
sprop-dci P P - - P sprop-dci P P - - P
sprop-sei P P - - P sprop-sei P P - - P
sprop-vps P P - - P sprop-vps P P - - P
sprop-sps P P - - P sprop-sps P P - - P
sprop-pps P P - - P sprop-pps P P - - P
sprop-sublayer-id P P - - P sprop-sublayer-id P P - - P
recv-sublayer-id O O O O - recv-sublayer-id O O O O -
sprop-ols-id P P - - P sprop-ols-id P P - - P
recv-ols-id X O X O - recv-ols-id X O X O -
Table 1. Interpretation of parameters for various combinations of
offers, answers, direction attributes, with and without recv-ols-id.
Columns that do not indicate offer or answer apply to both.
Legend: Legend:
C: configuration for sending and receiving bitstreams C: configuration for sending and receiving bitstreams
D: changeable configuration, same as C except possible D: changeable configuration, same as C, except possible
to answer with a different but consistent value (see the to answer with a different but consistent value (see the
semantics of the six parameters related to profile, tier, semantics of the six parameters related to profile, tier,
and level on these parameters being consistent) and level on these parameters being consistent)
P: properties of the bitstream to be sent P: properties of the bitstream to be sent
R: receiver capabilities R: receiver capabilities
O: operation point selection O: operation point selection
X: MUST NOT be present X: MUST NOT be present
-: not usable, when present MUST be ignored -: not usable, when present MUST be ignored
Figure 11: Interpretation of Parameters for Various Combinations
of Offers, Answers, and Direction Attributes, with and without
recv-ols-id.
Parameters used for declaring receiver capabilities are, in general, Parameters used for declaring receiver capabilities are, in general,
downgradable; i.e., they express the upper limit for a sender's downgradable, i.e., they express the upper limit for a sender's
possible behavior. Thus, a sender MAY select to set its encoder possible behavior. Thus, a sender MAY select to set its encoder
using only lower/lesser or equal values of these parameters. using only lower/lesser or equal values of these parameters.
When the answer does not include a recv-ols-id that is less than the When the answer does not include a recv-ols-id that is less than the
sprop-ols-id in the offer, parameters declaring a configuration point sprop-ols-id in the offer, parameters declaring a configuration point
are not changeable, with the exception of the level-id parameter for are not changeable, with the exception of the level-id parameter for
unicast usage, and these parameters express values a receiver expects unicast usage, and these parameters express values a receiver expects
to be used and MUST be used verbatim in the answer as in the offer. to be used and MUST be used verbatim in the answer as in the offer.
When a sender's capabilities are declared with the configuration When a sender's capabilities are declared with the configuration
skipping to change at page 58, line 26 skipping to change at line 2596
configurations in a single payload type. Thus, when multiple configurations in a single payload type. Thus, when multiple
configuration offers are made, each offer requires its own RTP configuration offers are made, each offer requires its own RTP
payload type associated with the offer. However, it is possible to payload type associated with the offer. However, it is possible to
offer multiple operation points using one configuration in a single offer multiple operation points using one configuration in a single
payload type by including sprop-vps in the offer and recv-ols-id in payload type by including sprop-vps in the offer and recv-ols-id in
the answer. the answer.
An implementation SHOULD be able to understand all media type An implementation SHOULD be able to understand all media type
parameters (including all optional media type parameters), even if it parameters (including all optional media type parameters), even if it
doesn't support the functionality related to the parameter. This, in doesn't support the functionality related to the parameter. This, in
conjunction with proper application logic in the implementation conjunction with proper application logic in the implementation,
allows the implementation, after having received an offer, to create allows the implementation, after having received an offer, to create
an answer by potentially downgrading one or more of the optional an answer by potentially downgrading one or more of the optional
parameters to the point where the implementation can cope, leading to parameters to the point where the implementation can cope, leading to
higher chances of interoperability beyond the most basic interop higher chances of interoperability beyond the most basic interop
points (for which, as described above, no optional parameters are points (for which, as described above, no optional parameters are
necessary). necessary).
Informative note: in implementations of previous H.26x payload | Informative note: In implementations of previous H.26x payload
formats it was occasionally observed that implementations were | formats, it was occasionally observed that implementations were
incapable of parsing most (or all) of the optional parameters. As | incapable of parsing most (or all) of the optional parameters.
a result, the offer-answer exchange resulted in a baseline | As a result, the offer/answer exchange resulted in a baseline
performance (using the default values for the optional parameters) | performance (using the default values for the optional
with the resulting suboptimal user experience. However, there are | parameters) with the resulting suboptimal user experience.
valid reasons to forego the implementation complexity of | However, there are valid reasons to forego the implementation
implementing the parsing of some or all of the optional | complexity of implementing the parsing of some or all of the
parameters, for example, when there is pre-determined knowledge, | optional parameters, for example, when there is predetermined
not negotiated by an SDP-based offer/answer process, of the | knowledge, not negotiated by an SDP-based offer/answer process,
capabilities of the involved systems (walled gardens, baseline | of the capabilities of the involved systems (walled gardens,
requirements defined in application standards higher up in the | baseline requirements defined in application standards higher
stack, and similar). | up in the stack, and similar).
An answerer MAY extend the offer with additional media format An answerer MAY extend the offer with additional media format
configurations. However, to enable their usage, in most cases a configurations. However, to enable their usage, in most cases, a
second offer is required from the offerer to provide the bitstream second offer is required from the offerer to provide the bitstream
property parameters that the media sender will use. This also has property parameters that the media sender will use. This also has
the effect that the offerer has to be able to receive this media the effect that the offerer has to be able to receive this media
format configuration, not only to send it. format configuration, not only to send it.
7.3.3. Multicast 7.3.3. Multicast
For bitstreams being delivered over multicast, the following rules For bitstreams being delivered over multicast, the following rules
apply: apply:
skipping to change at page 59, line 46 skipping to change at line 2659
as long as the three above rules are obeyed. as long as the three above rules are obeyed.
7.3.4. Usage in Declarative Session Descriptions 7.3.4. Usage in Declarative Session Descriptions
When VVC over RTP is offered with SDP in a declarative style, as in When VVC over RTP is offered with SDP in a declarative style, as in
Real Time Streaming Protocol (RTSP) [RFC7826] or Session Announcement Real Time Streaming Protocol (RTSP) [RFC7826] or Session Announcement
Protocol (SAP) [RFC2974], the following considerations are necessary. Protocol (SAP) [RFC2974], the following considerations are necessary.
* All parameters capable of indicating both bitstream properties and * All parameters capable of indicating both bitstream properties and
receiver capabilities are used to indicate only bitstream receiver capabilities are used to indicate only bitstream
properties. For example, in this case, the parameter profile-id, properties. For example, in this case, the parameters profile-id,
tier-id, level-id declares the values used by the bitstream, not tier-id, and level-id declare the values used by the bitstream,
the capabilities for receiving bitstreams. As a result, the not the capabilities for receiving bitstreams. As a result, the
following interpretation of the parameters MUST be used: following interpretation of the parameters MUST be used:
- Declaring actual configuration or bitstream properties: - Declaring actual configuration or bitstream properties:
o profile-id o profile-id
o tier-flag o tier-flag
o level-id o level-id
skipping to change at page 61, line 11 skipping to change at line 2720
reject (RTSP) or not participate in (SAP) the session. It reject (RTSP) or not participate in (SAP) the session. It
falls on the creator of the session to use values that are falls on the creator of the session to use values that are
expected to be supported by the receiving application. expected to be supported by the receiving application.
7.3.5. Considerations for Parameter Sets 7.3.5. Considerations for Parameter Sets
When out-of-band transport of parameter sets is used, parameter sets When out-of-band transport of parameter sets is used, parameter sets
MAY still be additionally transported in-band unless explicitly MAY still be additionally transported in-band unless explicitly
disallowed by an application, and some of these additional parameter disallowed by an application, and some of these additional parameter
sets may update some of the out-of-band transported parameter sets. sets may update some of the out-of-band transported parameter sets.
Update of a parameter set refers to the sending of a parameter set of An update of a parameter set refers to the sending of a parameter set
the same type using the same parameter set ID but with different of the same type using the same parameter set ID but with different
values for at least one other parameter of the parameter set. values for at least one other parameter of the parameter set.
8. Use with Feedback Messages 8. Use with Feedback Messages
The following subsections define the use of the Picture Loss The following subsections define the use of the Picture Loss
Indication (PLI) and Full Intra Request (FIR) feedback messages with Indication (PLI) and Full Intra Request (FIR) feedback messages with
[VVC]. The PLI is defined in [RFC4585], and the FIR message is [VVC]. The PLI is defined in [RFC4585], and the FIR message is
defined in [RFC5104]. In accordance with this memo, unlike [HEVC], a defined in [RFC5104]. In accordance with this memo, unlike [HEVC], a
sender MUST NOT send Slice Loss Indication (SLI) or Reference Picture sender MUST NOT send Slice Loss Indication (SLI) or Reference Picture
Selection Indication (RPSI), and a receiver SHOULD ignore RPSI and Selection Indication (RPSI), and a receiver SHOULD ignore RPSI and
treat a received SLI as a PLI. treat a received SLI as a PLI.
8.1. Picture Loss Indication (PLI) 8.1. Picture Loss Indication (PLI)
As specified in RFC 4585, Section 6.3.1, the reception of a PLI by a As specified in Section 6.3.1 of [RFC4585], the reception of a PLI by
media sender indicates "the loss of an undefined amount of coded a media sender indicates "the loss of an undefined amount of coded
video data belonging to one or more pictures". Without having any video data belonging to one or more pictures". Without having any
specific knowledge of the setup of the bitstream (such as use and specific knowledge of the setup of the bitstream (such as use and
location of in-band parameter sets, non-IRAP decoder refresh points, location of in-band parameter sets, non-IRAP decoder refresh points,
picture structures, and so forth), a reaction to the reception of an picture structures, and so forth), a reaction to the reception of a
PLI by a VVC sender SHOULD be to send an IRAP picture and relevant PLI by a VVC sender SHOULD be to send an IRAP picture and relevant
parameter sets; potentially with sufficient redundancy so to ensure parameter sets, potentially with sufficient redundancy so to ensure
correct reception. However, sometimes information about the correct reception. However, sometimes information about the
bitstream structure is known. For example, state could have been bitstream structure is known. For example, such information can be
established outside of the mechanisms defined in this document that parameter sets that have been conveyed out of band through mechanisms
parameter sets are conveyed out of band only, and stay static for the not defined in this document and that are known to stay static for
duration of the session. In that case, it is obviously unnecessary the duration of the session. In that case, it is obviously
to send them in-band as a result of the reception of a PLI. Other unnecessary to send them in-band as a result of the reception of a
examples could be devised based on a priori knowledge of different PLI. Other examples could be devised based on a priori knowledge of
aspects of the bitstream structure. In all cases, the timing and different aspects of the bitstream structure. In all cases, the
congestion control mechanisms of RFC 4585 MUST be observed. timing and congestion control mechanisms of [RFC4585] MUST be
observed.
8.2. Full Intra Request (FIR) 8.2. Full Intra Request (FIR)
The purpose of the FIR message is to force an encoder to send an The purpose of the FIR message is to force an encoder to send an
independent decoder refresh point as soon as possible, while independent decoder refresh point as soon as possible while observing
observing applicable congestion-control-related constraints, such as applicable congestion-control-related constraints, such as those set
those set out in [RFC8082]). out in [RFC8082].
Upon reception of a FIR, a sender MUST send an IDR picture. Upon reception of a FIR, a sender MUST send an IDR picture.
Parameter sets MUST also be sent, except when there is a priori Parameter sets MUST also be sent, except when there is a priori
knowledge that the parameter sets have been correctly established. A knowledge that the parameter sets have been correctly established. A
typical example for that is an understanding between sender and typical example for that is an understanding between the sender and
receiver, established by means outside this document, that parameter receiver, established by means outside this document, that parameter
sets are exclusively sent out-of-band. sets are exclusively sent out of band.
9. Security Considerations 9. Security Considerations
The scope of this Security Considerations section is limited to the The scope of this section is limited to the payload format itself and
payload format itself and to one feature of [VVC] that may pose a to one feature of [VVC] that may pose a particularly serious security
particularly serious security risk if implemented naively. The risk if implemented naively. The payload format, in isolation, does
payload format, in isolation, does not form a complete system. not form a complete system. Implementers are advised to read and
Implementers are advised to read and understand relevant security- understand relevant security-related documents, especially those
related documents, especially those pertaining to RTP (see the pertaining to RTP (see the Security Considerations section in
Security Considerations section in [RFC3550]), and the security of [RFC3550]) and the security of the call-control stack chosen (that
the call-control stack chosen (that may make use of the media type may make use of the media type registration of this memo).
registration of this memo). Implementers should also consider known Implementers should also consider known security vulnerabilities of
security vulnerabilities of video coding and decoding implementations video coding and decoding implementations in general and avoid those.
in general and avoid those.
Within this RTP payload format, and with the exception of the user Within this RTP payload format, and with the exception of the user
data SEI message as described below, no security threats other than data SEI message as described below, no security threats other than
those common to RTP payload formats are known. In other words, those common to RTP payload formats are known. In other words,
neither the various media-plane-based mechanisms, nor the signaling neither the various media-plane-based mechanisms nor the signaling
part of this memo, seems to pose a security risk beyond those common part of this memo seem to pose a security risk beyond those common to
to all RTP-based systems. all RTP-based systems.
RTP packets using the payload format defined in this specification RTP packets using the payload format defined in this specification
are subject to the security considerations discussed in the RTP are subject to the security considerations discussed in the RTP
specification [RFC3550], and in any applicable RTP profile such as specification [RFC3550] and in any applicable RTP profile, such as
RTP/AVP [RFC3551], RTP/AVPF [RFC4585], RTP/SAVP [RFC3711], or RTP/ RTP/AVP [RFC3551], RTP/AVPF [RFC4585], RTP/SAVP [RFC3711], or RTP/
SAVPF [RFC5124]. However, as "Securing the RTP Framework: Why RTP SAVPF [RFC5124]. However, as "Securing the RTP Framework: Why RTP
Does Not Mandate a Single Media Security Solution" [RFC7202] Does Not Mandate a Single Media Security Solution" [RFC7202]
discusses, it is not an RTP payload format's responsibility to discusses, it is not an RTP payload format's responsibility to
discuss or mandate what solutions are used to meet the basic security discuss or mandate what solutions are used to meet the basic security
goals like confidentiality, integrity and source authenticity for RTP goals, like confidentiality, integrity, and source authenticity for
in general. This responsibility lays on anyone using RTP in an RTP in general. This responsibility lays on anyone using RTP in an
application. They can find guidance on available security mechanisms application. They can find guidance on available security mechanisms
and important considerations in "Options for Securing RTP Sessions" and important considerations in "Options for Securing RTP Sessions"
[RFC7201]. The rest of this section discusses the security impacting [RFC7201]. The rest of this section discusses the security impacting
properties of the payload format itself. properties of the payload format itself.
Because the data compression used with this payload format is applied Because the data compression used with this payload format is applied
end-to-end, any encryption needs to be performed after compression. end to end, any encryption needs to be performed after compression.
A potential denial-of-service threat exists for data encodings using A potential denial-of-service threat exists for data encodings using
compression techniques that have non-uniform receiver-end compression techniques that have non-uniform receiver-end
computational load. The attacker can inject pathological datagrams computational load. The attacker can inject pathological datagrams
into the bitstream that are complex to decode and that cause the into the bitstream that are complex to decode and that cause the
receiver to be overloaded. [VVC] is particularly vulnerable to such receiver to be overloaded. [VVC] is particularly vulnerable to such
attacks, as it is extremely simple to generate datagrams containing attacks, as it is extremely simple to generate datagrams containing
NAL units that affect the decoding process of many future NAL units. NAL units that affect the decoding process of many future NAL units.
Therefore, the usage of data origin authentication and data integrity Therefore, the usage of data origin authentication and data integrity
protection of at least the RTP packet is RECOMMENDED but NOT protection of at least the RTP packet is RECOMMENDED but NOT REQUIRED
REQUIRED, based on the thoughts of [RFC7202] based on the thoughts of [RFC7202].
Like HEVC [RFC7798], [VVC] includes a user data Supplemental Like HEVC [RFC7798], [VVC] includes a user data Supplemental
Enhancement Information (SEI) message. This SEI message allows Enhancement Information (SEI) message. This SEI message allows
inclusion of an arbitrary bitstring into the video bitstream. Such a inclusion of an arbitrary bitstring into the video bitstream. Such a
bitstring could include JavaScript, machine code, and other active bitstring could include JavaScript, machine code, and other active
content. [VVC] leaves the handling of this SEI message to the content. [VVC] leaves the handling of this SEI message to the
receiving system. In order to avoid harmful side effects of the user receiving system. In order to avoid harmful side effects of the user
data SEI message, decoder implementations cannot naively trust its data SEI message, decoder implementations cannot naively trust its
content. For example, it would be a bad and insecure implementation content. For example, it would be a bad and insecure implementation
practice to forward any JavaScript a decoder implementation detects practice to forward any JavaScript a decoder implementation detects
skipping to change at page 63, line 43 skipping to change at line 2848
end points. end points.
10. Congestion Control 10. Congestion Control
Congestion control for RTP SHALL be used in accordance with RTP Congestion control for RTP SHALL be used in accordance with RTP
[RFC3550] and with any applicable RTP profile, e.g., AVP [RFC3551] or [RFC3550] and with any applicable RTP profile, e.g., AVP [RFC3551] or
AVPF [RFC4585]. If best-effort service is being used, an additional AVPF [RFC4585]. If best-effort service is being used, an additional
requirement is that users of this payload format MUST monitor packet requirement is that users of this payload format MUST monitor packet
loss to ensure that the packet loss rate is within an acceptable loss to ensure that the packet loss rate is within an acceptable
range. Packet loss is considered acceptable if a TCP flow across the range. Packet loss is considered acceptable if a TCP flow across the
same network path, and experiencing the same network conditions, same network path and experiencing the same network conditions would
would achieve an average throughput, measured on a reasonable achieve an average throughput, measured on a reasonable timescale,
timescale, that is not less than all RTP streams combined are that is not less than all RTP streams combined are achieved. This
achieved. This condition can be satisfied by implementing condition can be satisfied by implementing congestion-control
congestion-control mechanisms to adapt the transmission rate, the mechanisms to adapt the transmission rate, by implementing the number
number of layers subscribed for a layered multicast session, or by of layers subscribed for a layered multicast session, or by arranging
arranging for a receiver to leave the session if the loss rate is for a receiver to leave the session if the loss rate is unacceptably
unacceptably high. high.
The bitrate adaptation necessary for obeying the congestion control The bitrate adaptation necessary for obeying the congestion control
principle is easily achievable when real-time encoding is used, for principle is easily achievable when real-time encoding is used, for
example, by adequately tuning the quantization parameter. However, example, by adequately tuning the quantization parameter. However,
when pre-encoded content is being transmitted, bandwidth adaptation when pre-encoded content is being transmitted, bandwidth adaptation
requires the pre-coded bitstream to be tailored for such adaptivity. requires the pre-coded bitstream to be tailored for such adaptivity.
The key mechanisms available in [VVC] are temporal scalability, and The key mechanisms available in [VVC] are temporal scalability and
spatial/SNR scalability. A media sender can remove NAL units spatial/SNR scalability. A media sender can remove NAL units
belonging to higher temporal sublayers (i.e., those NAL units with a belonging to higher temporal sublayers (i.e., those NAL units with a
high value of TID) or higher spatio-SNR layers until the sending high value of TID) or higher spatio-SNR layers until the sending
bitrate drops to an acceptable range. bitrate drops to an acceptable range.
The mechanisms mentioned above generally work within a defined The mechanisms mentioned above generally work within a defined
profile and level and, therefore, no renegotiation of the channel is profile and level; therefore no renegotiation of the channel is
required. Only when non-downgradable parameters (such as profile) required. Only when non-downgradable parameters (such as profile)
are required to be changed does it become necessary to terminate and are required to be changed does it become necessary to terminate and
restart the RTP stream(s). This may be accomplished by using restart the RTP stream(s). This may be accomplished by using
different RTP payload types. different RTP payload types.
MANEs MAY remove certain unusable packets from the RTP stream when MANEs MAY remove certain unusable packets from the RTP stream when
that RTP stream was damaged due to previous packet losses. This can that RTP stream was damaged due to previous packet losses. This can
help reduce the network load in certain special cases. For example, help reduce the network load in certain special cases. For example,
MANEs can remove those FUs where the leading FUs belonging to the MANEs can remove those FUs where the leading FUs belonging to the
same NAL unit have been lost or those dependent slice segments when same NAL unit have been lost or those dependent slice segments when
the leading slice segments belonging to the same slice have been the leading slice segments belonging to the same slice have been
lost, because the trailing FUs or dependent slice segments are lost, because the trailing FUs or dependent slice segments are
meaningless to most decoders. MANE can also remove higher temporal meaningless to most decoders. MANE can also remove higher temporal
scalable layers if the outbound transmission (from the MANE's scalable layers if the outbound transmission (from the MANE's
viewpoint) experiences congestion. viewpoint) experiences congestion.
11. IANA Considerations 11. IANA Considerations
A new media type, as specified in Section 7.1 of this memo, has been A new media type has been registered with IANA; see Section 7.1.
registered with IANA.
12. Acknowledgements
Dr. Byeongdoo Choi is thanked for the video codec related technical
discussion and other aspects in this memo. Xin Zhao and Dr. Xiang Li
are thanked for their contributions on [VVC] specification
descriptive content. Spencer Dawkins is thanked for his valuable
review comments that led to great improvements of this memo. Some
parts of this specification share text with the RTP payload format
for HEVC [RFC7798]. We thank the authors of that specification for
their excellent work.
13. References 12. References
13.1. Normative References 12.1. Normative References
[ISO23090-3] [ISO23090-3]
ISO/IEC 23090-3, "Information technology - Coded International Organization for Standardization,
representation of immersive media Part 3 Versatile Video "Information technology - Coded representation of
Coding", 2021, <https://www.iso.org/standard/73022.html>. immersive media - Part 3: Versatile video coding", ISO/
IEC 23090-3:2022, September 2022,
<https://www.iso.org/standard/73022.html>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model [RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model
with Session Description Protocol (SDP)", RFC 3264, with Session Description Protocol (SDP)", RFC 3264,
DOI 10.17487/RFC3264, June 2002, DOI 10.17487/RFC3264, June 2002,
<https://www.rfc-editor.org/info/rfc3264>. <https://www.rfc-editor.org/info/rfc3264>.
skipping to change at page 65, line 35 skipping to change at line 2926
[RFC3551] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and [RFC3551] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and
Video Conferences with Minimal Control", STD 65, RFC 3551, Video Conferences with Minimal Control", STD 65, RFC 3551,
DOI 10.17487/RFC3551, July 2003, DOI 10.17487/RFC3551, July 2003,
<https://www.rfc-editor.org/info/rfc3551>. <https://www.rfc-editor.org/info/rfc3551>.
[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. [RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.
Norrman, "The Secure Real-time Transport Protocol (SRTP)", Norrman, "The Secure Real-time Transport Protocol (SRTP)",
RFC 3711, DOI 10.17487/RFC3711, March 2004, RFC 3711, DOI 10.17487/RFC3711, March 2004,
<https://www.rfc-editor.org/info/rfc3711>. <https://www.rfc-editor.org/info/rfc3711>.
[RFC4556] Zhu, L. and B. Tung, "Public Key Cryptography for Initial
Authentication in Kerberos (PKINIT)", RFC 4556,
DOI 10.17487/RFC4556, June 2006,
<https://www.rfc-editor.org/info/rfc4556>.
[RFC4585] Ott, J., Wenger, S., Sato, N., Burmeister, C., and J. Rey, [RFC4585] Ott, J., Wenger, S., Sato, N., Burmeister, C., and J. Rey,
"Extended RTP Profile for Real-time Transport Control "Extended RTP Profile for Real-time Transport Control
Protocol (RTCP)-Based Feedback (RTP/AVPF)", RFC 4585, Protocol (RTCP)-Based Feedback (RTP/AVPF)", RFC 4585,
DOI 10.17487/RFC4585, July 2006, DOI 10.17487/RFC4585, July 2006,
<https://www.rfc-editor.org/info/rfc4585>. <https://www.rfc-editor.org/info/rfc4585>.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006, Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
<https://www.rfc-editor.org/info/rfc4648>. <https://www.rfc-editor.org/info/rfc4648>.
skipping to change at page 66, line 35 skipping to change at line 2966
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8866] Begen, A., Kyzivat, P., Perkins, C., and M. Handley, "SDP: [RFC8866] Begen, A., Kyzivat, P., Perkins, C., and M. Handley, "SDP:
Session Description Protocol", RFC 8866, Session Description Protocol", RFC 8866,
DOI 10.17487/RFC8866, January 2021, DOI 10.17487/RFC8866, January 2021,
<https://www.rfc-editor.org/info/rfc8866>. <https://www.rfc-editor.org/info/rfc8866>.
[VSEI] "Versatile supplemental enhancement information messages [VSEI] ITU-T, "Versatile supplemental enhancement information
for coded video bitstreams", 2020, messages for coded video bitstreams", ITU-T
Recommendation H.274, May 2022,
<https://www.itu.int/rec/T-REC-H.274>. <https://www.itu.int/rec/T-REC-H.274>.
[VVC] "Versatile Video Coding, ITU-T Recommendation H.266", [VVC] ITU-T, "Versatile Video Coding", ITU-T
2020, <http://www.itu.int/rec/T-REC-H.266>. Recommendation H.266, April 2022,
<http://www.itu.int/rec/T-REC-H.266>.
13.2. Informative References 12.2. Informative References
[CABAC] and et al, "Transform coefficient coding in HEVC, IEEE [CABAC] Sole, J., et al., "Transform coefficient coding in HEVC",
Transactions on Circuits and Systems for Video IEEE Transactions on Circuits and Systems for Video
Technology", DOI 10.1109/TCSVT.2012.2223055, December Technology, DOI 10.1109/TCSVT.2012.2223055, December 2012,
2012, <https://doi.org/10.1109/TCSVT.2012.2223055>. <https://doi.org/10.1109/TCSVT.2012.2223055>.
[HEVC] "High efficiency video coding, ITU-T Recommendation [HEVC] ITU-T, "High efficiency video coding", ITU-T
H.265", 2019, <https://www.itu.int/rec/T-REC-H.265>. Recommendation H.265, August 2021,
<https://www.itu.int/rec/T-REC-H.265>.
[MPEG2S] IS0/IEC, "Information technology - Generic coding of [MPEG2S] International Organization for Standardization,
moving pictures and associated audio information - Part 1: "Information technology - Generic coding of moving
Systems, ISO International Standard 13818-1", 2013. pictures and associated audio information - Part 1:
Systems", ISO/IEC 13818-1:2022, September 2022.
[RFC2974] Handley, M., Perkins, C., and E. Whelan, "Session [RFC2974] Handley, M., Perkins, C., and E. Whelan, "Session
Announcement Protocol", RFC 2974, DOI 10.17487/RFC2974, Announcement Protocol", RFC 2974, DOI 10.17487/RFC2974,
October 2000, <https://www.rfc-editor.org/info/rfc2974>. October 2000, <https://www.rfc-editor.org/info/rfc2974>.
[RFC6184] Wang, Y.-K., Even, R., Kristensen, T., and R. Jesup, "RTP [RFC6184] Wang, Y.-K., Even, R., Kristensen, T., and R. Jesup, "RTP
Payload Format for H.264 Video", RFC 6184, Payload Format for H.264 Video", RFC 6184,
DOI 10.17487/RFC6184, May 2011, DOI 10.17487/RFC6184, May 2011,
<https://www.rfc-editor.org/info/rfc6184>. <https://www.rfc-editor.org/info/rfc6184>.
skipping to change at page 68, line 5 skipping to change at line 3034
[RFC7798] Wang, Y.-K., Sanchez, Y., Schierl, T., Wenger, S., and M. [RFC7798] Wang, Y.-K., Sanchez, Y., Schierl, T., Wenger, S., and M.
M. Hannuksela, "RTP Payload Format for High Efficiency M. Hannuksela, "RTP Payload Format for High Efficiency
Video Coding (HEVC)", RFC 7798, DOI 10.17487/RFC7798, Video Coding (HEVC)", RFC 7798, DOI 10.17487/RFC7798,
March 2016, <https://www.rfc-editor.org/info/rfc7798>. March 2016, <https://www.rfc-editor.org/info/rfc7798>.
[RFC7826] Schulzrinne, H., Rao, A., Lanphier, R., Westerlund, M., [RFC7826] Schulzrinne, H., Rao, A., Lanphier, R., Westerlund, M.,
and M. Stiemerling, Ed., "Real-Time Streaming Protocol and M. Stiemerling, Ed., "Real-Time Streaming Protocol
Version 2.0", RFC 7826, DOI 10.17487/RFC7826, December Version 2.0", RFC 7826, DOI 10.17487/RFC7826, December
2016, <https://www.rfc-editor.org/info/rfc7826>. 2016, <https://www.rfc-editor.org/info/rfc7826>.
Appendix A. Change History Acknowledgements
To RFC Editor: PLEASE REMOVE ThIS SECTION BEFORE PUBLICATION
draft-zhao-payload-rtp-vvc-00 ........ initial version
draft-zhao-payload-rtp-vvc-01 ........ editorial clarifications and
corrections
draft-ietf-payload-rtp-vvc-00 ........ initial WG draft
draft-ietf-payload-rtp-vvc-01 ........ VVC specification update
draft-ietf-payload-rtp-vvc-02 ........ VVC specification update
draft-ietf-payload-rtp-vvc-03 ........ VVC coding tool introduction
update
draft-ietf-payload-rtp-vvc-04 ........ VVC coding tool introduction
update
draft-ietf-payload-rtp-vvc-05 ........ reference udpate and adding
placement for open issues
draft-ietf-payload-rtp-vvc-06 ........ address editor's note
draft-ietf-payload-rtp-vvc-07 ........ address editor's notes
draft-ietf-payload-rtp-vvc-08 ........ address editor's notes
draft-ietf-payload-rtp-vvc-09 ........ address editor's notes
draft-ietf-payload-rtp-vvc-10 ........ address editor's notes
draft-ietf-payload-rtp-vvc-11 ........ address editor's notes
draft-ietf-payload-rtp-vvc-12 ........ address editor's notes
draft-ietf-payload-rtp-vvc-13 ........ address editor's notes
draft-ietf-payload-rtp-vvc-14 ........ address 2nd WGLC comments Dr. Byeongdoo Choi is thanked for the video-codec-related technical
discussion and other aspects in this memo. Xin Zhao and Dr. Xiang Li
are thanked for their contributions on [VVC] specification
descriptive content. Spencer Dawkins is thanked for his valuable
review comments that led to great improvements of this memo. Some
parts of this specification share text with the RTP payload format
for HEVC [RFC7798]. We thank the authors of that specification for
their excellent work.
Authors' Addresses Authors' Addresses
Shuai Zhao Shuai Zhao
Intel Intel
2200 Mission College Blvd 2200 Mission College Blvd
Santa Clara, 95054 Santa Clara, 95054
United States of America United States of America
Email: shuai.zhao@ieee.org Email: shuai.zhao@ieee.org
Stephan Wenger Stephan Wenger
Tencent Tencent
2747 Park Blvd 2747 Park Blvd
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