Method and apparatus for video processing, method and medium for storing bitstream

Abstract

Examples of video encoding methods and apparatuses and video decoding methods and apparatuses are described. An example method of video processing includes performing a conversion between a video and a bitstream of the video according to a rule, wherein the rule specifies a sub-bitstream extraction process by which an output sub-bitstream is extracted from the bitstream without removing particular types of and having particular network abstraction layer (NAL) unit header identification NAL units, wherein the particular types include access unit delimiter (AUD) NAL units.

Description

[0001] Cross-references to related applications

[0002] Pursuant to the applicable patent law and / or rules of the Paris Convention, this application claims priority and interest in U.S. Provisional Patent Application No. 63 / 029,308, filed May 22, 2020. For all purposes required by law, the entire disclosure of the aforementioned application is incorporated herein by reference as part of the disclosure of this application. Technical Field

[0003] The patent document relates to image and video encoding and decoding. Background Technology

[0004] Digital video consumes the largest share of bandwidth in the internet and other digital communication networks. As the number of connected user devices capable of receiving and displaying video increases, the bandwidth demand for digital video is expected to continue to grow. Summary of the Invention

[0005] This document discloses techniques that can be used by video encoders and decoders to perform video encoding or decoding.

[0006] In one example aspect, a method for video processing is disclosed. This method includes performing a conversion between a multi-layered video and a bitstream of the video, based on rules specifying maximum allowed values ​​for temporal layer identifier values ​​of sub-bitstreams extracted from the bitstream.

[0007] In another example, a method for video processing is disclosed. This method includes: performing a conversion between video and a video bitstream according to a rule, wherein the rule defines Network Abstraction Layer (NAL) units to be extracted from the bitstream during a sub-bitstream extraction process of the output sub-bitstream, and wherein the rule specifies that the sub-bitstream is derived based on whether a list of NAL unit header identifier values ​​in the output layer set (OLS) with a target OLS index excludes all values ​​of NAL unit header identifiers in all Video Codec Layer (VCL) NAL units in the bitstream input to the sub-bitstream extraction process.

[0008] In another example, a method for video processing is disclosed. This method includes performing a conversion between video and a video bitstream according to rules, wherein the rules define Network Abstraction Layer (NAL) units to be extracted from the bitstream during a sub-bitstream extraction process of the output sub-bitstream, and wherein the rules specify that, in response to the payload type of a first Supplemental Enhancement Information (SEI) message included in the SEI NAL unit, the SEI NAL unit is not allowed to contain an SEI message with a specific payload type.

[0009] In another example, a method for video processing is disclosed. This method includes performing a conversion between video and a video bitstream according to format rules, wherein the format rules specify that the bitstream includes a flag indicating whether one or more non-scalable nested supplementary enhancement information (SEI) messages of one or more specific payload types are applied to all output layer sets of the codec layer reference.

[0010] In another example, a method for video processing is disclosed. This method includes performing a conversion between a video and a video bitstream according to rules, wherein the rules specify a sub-bitstream extraction process by which an output sub-bitstream is extracted from the bitstream without removing specific types of Network Abstraction Layer (NAL) units with specific NAL unit header identifier values, wherein the specific type includes Access Unit Delimiter (AUD) NAL units.

[0011] In another example, a method for video processing is disclosed. This method includes performing a conversion between a video comprising one or more layers and a video bitstream according to a rule, wherein the rule specifies the removal of Network Abstraction Layer (NAL) units, including Scalable Nested Supplementary Enhancement Information (SEI) messages applied to layers not included in the Target Output Layer Set (OLS), during sub-bitstream extraction.

[0012] In another example, a method for video processing is disclosed. This method includes performing a conversion between a video comprising one or more layers and a bitstream of that video according to a rule, wherein the rule specifies that, during sub-bitstream extraction, a non-scalable nested SEI message is generated by extracting a scalable nested SEI message from a scalable nested SEI message based on a first flag indicating whether a Supplemental Enhancement Information (SEI) message is applied to a specific Output Layer Set (OLS) and a second flag indicating whether the SEI message is applied to all sub-pictures or only to a specific sub-picture.

[0013] In another example, a method for video processing is disclosed. This method includes performing a conversion between a video comprising one or more layers and a video bitstream according to a rule, wherein the rule specifies that, during sub-bitstream extraction, a non-scalable nested SEI message is generated by extracting multiple scalable nested SEI messages from a first Supplemental Enhancement Information (SEI) Network Abstraction Layer (NAL) unit in the picture unit.

[0014] In another example, a method for video processing is disclosed. This method includes performing a conversion between a video comprising one or more layers and a video bitstream according to rules, wherein the rules specify a sub-bitstream extraction process to generate an output bitstream, and wherein the rules specify processing of one or more Supplemental Enhancement Information (SEI) Network Abstraction Layer (NAL) units during the sub-bitstream extraction process.

[0015] In yet another example, a video encoder apparatus is disclosed. The video encoder includes a processor configured to implement the methods described above.

[0016] In yet another example, a video decoder apparatus is disclosed. The video decoder includes a processor configured to implement the methods described above.

[0017] In yet another example, a computer-readable medium on which code is stored is disclosed. This code embodies one of the methods described herein in the form of processor-executable code.

[0018] These and other features will be described in this document. Attached Figure Description

[0019] Figure 1 This is a block diagram illustrating a video encoding and decoding system according to some embodiments of the disclosed technology.

[0020] Figure 2 This is a block diagram of an example hardware platform used for video processing.

[0021] Figure 3 This is a flowchart of an example method for video processing.

[0022] Figure 4 This is a block diagram illustrating an example video encoding / decoding system.

[0023] Figure 5 This is a block diagram illustrating an encoder according to some embodiments of the disclosed technology.

[0024] Figure 6 This is a block diagram illustrating a decoder according to some embodiments of the disclosed technology.

[0025] Figures 7A to 7D This is a flowchart of an example method for video processing based on some implementations of the disclosed technology.

[0026] Figure 8 This is a flowchart of an example method for video processing based on some implementations of the disclosed technology.

[0027] Figure 9 This is a flowchart of an example method for video processing based on some implementations of the disclosed technology.

[0028] Figures 10A to 10C This is a flowchart of an example method for video processing based on some implementations of the disclosed technology. Detailed Implementation

[0029] The use of section headings in this document is for ease of understanding and not to limit the applicability of the techniques and embodiments disclosed in each section to that section only. Furthermore, the use of H.266 terminology in some descriptions is merely for ease of understanding and not to limit the scope of the disclosed techniques. Therefore, the techniques described herein are also applicable to other video codec protocols and designs.

[0030] 1. Introduction

[0031] This document relates to video codec techniques. Specifically, it concerns improvements to the general sub-bitstream extraction process, signaling for picture-level HRD parameters, and the inclusion of SEI messages in the SEI NAL unit. These ideas can be applied individually or in various combinations to any video codec standard or non-standard video codec that supports multi-layer video codecs, such as the Universal Video Codec (VVC) currently under development.

[0032] 2. Abbreviations

[0033] APS Adapter Parameter Set

[0034] AU Access Unit

[0035] AUD Access Unit Delimiter

[0036] AVC Advanced Video Codec

[0037] CLVS codec layer video sequence

[0038] CPB image buffer for encoding / decoding

[0039] CRA Cleans up random access

[0040] CTU (Codec Tree Unit)

[0041] CVS encoded video sequences

[0042] DCI decoding capability information

[0043] DPB decoding image buffer

[0044] End of EOB bitstream

[0045] End of EOS sequence

[0046] GDR Progressive Decoding Refresh

[0047] HEVC High-Efficiency Video Encoding and Decoding

[0048] HRD Assumption Reference Decoder

[0049] IDR instantaneous decoding refresh

[0050] Interlayer prediction in ILP

[0051] ILRP interlayer reference image

[0052] JEM Joint Exploration Model

[0053] LTRP Long-Term Reference Image

[0054] MCTS Motion Constraint Pieces

[0055] NAL Network Abstraction Layer

[0056] OLS Output Layer Set

[0057] PH image header

[0058] PPS Image Parameter Set

[0059] PTL configuration files, hierarchies, and levels

[0060] PU Image Unit

[0061] RAP Random Access Point

[0062] RBSP raw byte sequence payload

[0063] SEI Supplemental Enhancement Information

[0064] SPS Sequence Parameter Set

[0065] STRP Short-Term Reference Image

[0066] SVC Scalable Video Codec

[0067] VCL (Video Codec Layer)

[0068] VPS Video Parameter Set

[0069] VTM VVC Test Model

[0070] VUI Video Availability Information

[0071] VVC Multi-Functional Video Encoding and Decoding

[0072] 3. Preliminary Discussion

[0073] Video codec standards have primarily evolved through the development of well-known ITU-T and ISO / IEC standards. ITU-T developed H.261 and H.263, while ISO / IEC developed MPEG-1 and MPEG-4 Visual. These two organizations jointly developed the H.262 / MPEG-2 video and H.264 / MPEG-4 Advanced Video Codec (AVC) and H.265 / HEVC standards. Since H.262, video codec standards have been based on a hybrid video codec architecture, utilizing temporal prediction plus transform coding. To explore future video codec technologies beyond HEVC, VCEG and MPEG jointly established the Joint Video Exploration Group (JVET) in 2015. Since then, JVET has adopted many new methods and incorporated them into reference software called the Joint Exploration Model (JEM). JVET meetings are held quarterly, and the goal of the new codec standard is to reduce the bitrate by 50% compared to HEVC. The new video codec standard was officially named Universal Video Codec (VVC) at the JVET meeting in April 2018, and the first version of the VVC Test Model (VTM) was also released at that time. Due to ongoing efforts to standardize VVC, the new codec technology has been adopted into the VVC standard at every JVET meeting. The VVC working draft and the VTM test model are updated after each meeting. The current goal of the VVC project is to achieve Technical Finalization (FDIS) at the meeting in July 2020.

[0074] 3.1 Changes in image resolution within a sequence

[0075] In AVC and HEVC, the spatial resolution of an image cannot be changed unless a new sequence with a new SPS begins with an IRAP image. VVC allows changing the image resolution within a sequence at points where IRAP images are not encoded or decoded; IRAP images are always intra-frame encoded and decoded. This feature is sometimes called Reference Image Resampling (RPR) because it requires resampling the reference image used for inter-frame prediction when the reference image has a different resolution than the current image being decoded.

[0076] The scaling ratio is limited to greater than or equal to 1 / 2 (2x downsampling from the reference image to the current image) and less than or equal to 8 (8x upsampling). Three sets of resampling filters with different frequency cutoffs are specified to handle various scaling ratios between the reference and current images. The three sets of resampling filters are applied to scaling ratios ranging from 1 / 2 to 1 / 1.75, from 1 / 1.75 to 1 / 1.25, and from 1 / 1.25 to 8, respectively. Each set of resampling filters has 16 phases for luma and 32 phases for chroma, which is the same as in the case of motion-compensated interpolation filters. In fact, the normal MC interpolation process is a special case of the resampling process, with scaling ratios ranging from 1 / 1.25 to 8. The horizontal and vertical scaling ratios are derived based on the image width and height, as well as the left, right, top, and bottom scaling offsets specified for the reference and current images.

[0077] Other aspects of the VVC design that support this feature differ from HEVC include: i) Picture resolution and the corresponding consistency window are signaled in the PPS instead of the SPS, where the maximum picture resolution is signaled. ii) For a single-layer bitstream, each picture memory (a slot in the DPB used to store a decoded picture) occupies the buffer size required to store the decoded picture with the maximum picture resolution.

[0078] 3.2 General and Scalable Video Codec (SVC) in VVC

[0079] Scalable video codec (SVC, sometimes also called scalability in video codec) refers to video codec that uses a base layer (BL), sometimes called a reference layer (RL), and one or more scalable enhancement layers (EL). In SVC, the base layer can carry video data with a base quality level. One or more enhancement layers can carry additional video data to support, for example, higher spatial, temporal, and / or signal-to-noise ratio (SNR) levels. Enhancement layers can be defined relative to previously codecped layers. For example, the bottom layer can be used as a BL, while the top layer can be used as an EL. Intermediate layers can act as ELs or RLs, or both. For example, an intermediate layer (e.g., a layer that is neither the lowest nor the highest layer) can be an EL of the layer below the intermediate layer (e.g., the base layer or any intermediate enhancement layer) and simultaneously act as an RL of one or more enhancement layers above the intermediate layer. Similarly, in the multi-view or 3D extension of the HEVC standard, there can be multiple views, and information from one view can be used to codec (e.g., encode or decode) information from another view (e.g., motion estimation, motion vector prediction, and / or other redundancy).

[0080] In SVC, the parameters used by the encoder or decoder are grouped into parameter sets based on the codec level they might utilize (e.g., video level, sequence level, picture level, stripe level, etc.). For example, parameters that can be used by one or more codecs of different layers in a bitstream for a video sequence may be included in the Video Parameter Set (VPS), and parameters that can be used by one or more pictures in a codec video sequence may be included in the Sequence Parameter Set (SPS). Similarly, parameters used by one or more stripes in a picture may be included in the Picture Parameter Set (PPS), and additional parameters specific to a single strip may be included in the stripe header. Likewise, indications of which parameter set(s) a particular layer uses at a given time can be provided at various codec levels.

[0081] Because of the support for Reference Picture Resampling (RPR) in VVC, it is possible to design support for bitstreams containing multiple layers (e.g., two layers with SD and HD resolutions in VVC) without requiring any additional signal processing-level codec tools, as the upsampling required for spatial scalability support can be achieved using only RPR upsampling filters. However, supporting scalability requires a high level of syntax changes (compared to not supporting scalability at all). Scalability support was specified in VVC version 1. Unlike scalability support in any earlier video codec standards (including extensions to AVC and HEVC), VVC's scalability is designed to be as friendly as possible to single-layer decoder designs. The decoding capability of multi-layer bitstreams is specified as if there were only a single layer in the bitstream. For example, decoding capabilities such as DPB size are specified in a way that is independent of the number of layers in the bitstream to be decoded. Essentially, decoders designed for single-layer bitstreams do not require many changes to be able to decode multi-layer bitstreams. Compared to the multi-layer extension designs of AVC and HEVC, HLS is significantly simplified at the expense of some flexibility. For example, IRAPU requires a picture of every layer present in CVS.

[0082] 3.3 Parameter Set

[0083] AVC, HEVC, and VVC specify parameter sets. Parameter set types include SPS, PPS, APS, and VPS. AVC, HEVC, and VVC all support SPS and PPS. VPS was introduced with HEVC and is used in both HEVC and VVC. APS is not included in AVC or HEVC, but it is included in the latest VVC draft text.

[0084] SPS is designed to carry sequence-level header information, while PPS is designed to carry infrequently changing image-level header information. Using SPS and PPS, infrequently changing information does not need to be repeated for each sequence or image, thus avoiding redundant signaling. Furthermore, the use of SPS and PPS enables out-of-band transmission of important header information, thereby not only avoiding the need for redundant transmission but also improving error resilience.

[0085] The VPS was introduced to carry sequence-level header information common to all layers in a multi-layer bitstream.

[0086] The purpose of introducing APS is to carry such image-level or stripe-level information, which requires a considerable number of bits to encode and decode, can be shared by multiple images, and can have a considerable number of different variations in the sequence.

[0087] 3.4 General Sub-Bitstream Extraction Process

[0088] Clause C.6 of the latest VVC text specifies the general sub-bitstream extraction procedure as follows:

[0089] C6 sub-bit stream extraction process

[0090] The inputs to this process are the bitstream inBitstream, the target OLS index targetOlsIdx, and the highest target TemporalId value tIdTarget.

[0091] The output of this process is the sub-bit stream outBitstream.

[0092] The requirement for bitstream consistency of the input bitstream is that any output sub-bitstream that satisfies all of the following conditions should be a consistent bitstream:

[0093] – The output sub-bitstream is the output of the procedure specified in this clause, where the bitstream targetOlsIdx is equal to the index of the OLS list specified by the VPS, and tIdTarget is equal to any value in the range of 0 to 6 (inclusive).

[0094] – The output sub-bitstream contains at least one VCL NAL unit, where nuh_layer_id is equal to each nuh_layer_id value in LayerIdInOls[targetOlsIdx].

[0095] – The output sub-bitstream contains at least one VCL NAL unit, where TemporalId is equal to tIdTarget.

[0096] Note – A consistent bitstream contains one or more codec stripe NAL units with TemporalId equal to 0, but not necessarily codec stripe NAL units with nuh_layer_id equal to 0.

[0097] The following is an example of exporting the sub-bitstream:

[0098] 1. The bitstream outBitstream is set to be the same as the bitstream inBitstream.

[0099] 2. Remove all NAL cells from outBitstream whose TemporalId is greater than tIdTarget.

[0100] 3. Remove all NAL units from outBitstream whose nal_unit_type is not equal to any of VPS_NUT, DCI_NUT, and EOB_NUT and whose nuh_layer_id is not included in the list LayerIdInOls[targetOlsIdx].

[0101] 4. Remove all VCL NAL units from outBitstream that satisfy all of the following conditions, as well as associated non-VCL NAL units whose nal_unit_type is equal to PH_NUT, FD_NUT, SUFFIX_SEI_NUT, and PREFIX_SEI_NUT and whose PayloadType is not equal to 0, 1, or 130:

[0102] –nal_unit_type equals TRAIL_NUT, STSA_NUT, RADL_NUT, or RASL_NUT, or nal_unit_type equals GDR_NUT, and the associated ph_recovery_poc_cnt is not equal to 0.

[0103] – For j values ​​in the range of 0 to NumLayersInOls[targetOlsIdx]-1 (inclusive), nuh_layer_id is equal to LayerIdInOls[targetOlsIdx][j].

[0104] –TemporalId is greater than or equal to NumSubLayersInLayerInOLS[targetOlsIdx][GeneralLayerIdx[nuh_layer_id]].

[0105] 5. Remove all SEI NAL units from outBitstream that contain scalable nested SEI messages with sn_ols_flag equal to 1 and no i value in the range from 0 to sn_num_olss_minus1 (inclusive), such that NestingOlsIdx[i] equals targetOlsIdx.

[0106] 6. When LayerIdInOls[targetOlsIdx] does not include all values ​​of nuh_layer_id in all NAL units of the bitstream, the following applies:

[0107] a. Remove all SEI NAL units from outBitstream that contain non-scalable nested SEI messages with payloadType equal to 0 (BP) or 130 (DUI).

[0108] b. When general_same_pic_timing_in_all_ols_flag equals 0, remove all SEI NAL cells from outBitstream that contain non-scalable nested SEI messages with payloadType equal to 1 (PT).

[0109] c. When outBitstream contains SEI NAL cells with scalable nested SEI messages containing sn_ols_flag equal to 1, and when it applies to outBitstream (NestingOlsIdx[i] equals targetOlsIdx), the following applies:

[0110] – If general_same_pic_timing_in_all_ols_flag equals 0, then extract the appropriate non-scalable nested SEI messages with payloadType equal to 0 (BP), 1 (PT), or 130 (DUI) from the scalable nested SEI messages and include these SEI messages in outBitstream.

[0111] - Otherwise (general_same_pic_timing_in_all_ols_flag equals 1), extract the appropriate non-scalable nested SEI messages with payloadType equal to 0 (BP) or 130 (DUI) from the scalable nested SEI messages, and include these SEI messages in outBitstream.

[0112] 4. The technical problem solved by the disclosed technical solution

[0113] The existing design of the general sub-bitstream extraction process and related other parts in the latest VVC text (in JVET-R2001-vA / v10) has the following problems:

[0114] 1) When the output sub-bitstream is required to be a consistent bitstream, the value of tIdTarget is in the range of 0 to 6 (inclusive). However, in many bitstreams, the highest TemporalId value is less than 6, which is specified by the syntax element vps_max_sublayers_minus1.

[0115] 2) When present, the Access Unit Delimiter (AUD) NAL unit can have any nuh_layer_id value. However, step 3 of the sub-bitstream extraction process removes the AUD NAL unit, whose nuh_layer_id value is not included in the list LayerIdInOls[targetOlsIdx].

[0116] 3) Some SEI NAL units contain scalable nested SEI messages with sn_ols_flag equal to 0, and the applicable layer indicated in the scalable nested SEI message does not include any layer in the target OLS; that is, no applicable layer's nuh_layer_id value is not included in the list LayerIdInOls[targetOlsIdx]. These SEI NAL units should also be removed.

[0117] 4) The condition in step 6, namely "when LayerIdInOls[targetOlsIdx] does not include all values ​​of nuh_layer_id in all NAL units of the bitstream", has the following two problems.

[0118] a. This condition does not apply when a DCI, VPS, AUD, or EOB NAL cell exists and its nuh_layer_id is not equal to any nuh_layer_id value of the VCL NAL cell.

[0119] b. The phrase “bit stream” is unclear because it involves two bit streams in the context: inBitstream and outBitstream.

[0120] 5) Step 6.c extracts scalable nested SEI messages from scalable nested SEI messages where sn_ols_flag equals 1 and sn_subpic_flag equals 1, to generate non-scalable nested SEI messages. Such scalable nested SEI messages only correspond to specific sub-images and therefore should not be extracted.

[0121] 6) In step 6.c, when multiple scalable nested SEI messages are extracted from a SEI NAL unit seiNalUnitA as non-scalable nested SEI messages, they should still be included in a single SEI NAL unit seiNalUnitB, and the SEI NAL unit seiNalUnitB should be included in the same PU that contains the SEI NAL unit seiNalUnitA. However, this is not specifically stipulated.

[0122] 7) Step 6.c should remove all SEI NAL cells from outBitstream, from which some SEI messages have been extracted and included as non-scalable nested SEI messages. However, this is not specifically stipulated.

[0123] 8) The constraint that an SEI NAL unit should not contain SEI messages with payloadTypes other than 0 (BP), 1 (PT), 130 (DUI), or 133 (scalable nesting) when the SEI NAL unit contains SEI messages with payloadTypes equal to 0, 1, or 130 is missing. This results in the removal of SEI messages in step 4 involving more than just the removal of SEI NAL units.

[0124] 9) The flag `general_same_pic_timing_in_all_ols_flag` only specifies whether non-scalable nested PT SEI messages apply to all OLS. However, the information carried in DUI SEI messages is similar in purpose to that in PT SEI messages.

[0125] 5. List of technical solutions and implementation examples

[0126] To address the aforementioned and other issues, the following summarized methods are presented. These items should be considered as examples for explaining general concepts, not as narrow interpretations. Furthermore, these items can be used individually or in combination in any way.

[0127] 1) To solve problem 1, the condition that the output sub-bitstream is a consistent bitstream is specified, such that the value of tIdTarget is specified in the range of 0 to vps_max_sublayers_minus1 (inclusive of the endpoint).

[0128] a. Alternatively, specify the condition that the output sub-bitstream must be a consistent bitstream, such that when there are more than one layer in the input bitstream, the value of tIdTarget is specified in the range of 0 to vps_max_sublayers_minus1 (inclusive of the endpoint), and when there is only one layer in the input bitstream, the value of tIdTarget is specified in the range of 0 to sps_max_sublayers_minus1 (inclusive of the endpoint).

[0129] 2) To address problem 2, a generic sub-bitstream extraction procedure is defined, ensuring that AUD NAL units are processed in the same way as NAL units with nal_unit_type equal to VPS_NUT, DCI_NUT, or EOB_NUT. In other words, based on the nuh_layer_id value, no AUD NAL units are removed from the output bitstream outBitstream.

[0130] 3) To address problem 3, a general sub-bitstream extraction process is defined, such that the output bitstream outBitstream will remove the SEINAL unit containing the scalable nested SEI message with sn_ols_flag equal to 0, and the applicable layer indicated in the scalable nested SEI message does not include any layer in the target OLS.

[0131] a. In one example, it is specified that all SEINAL units containing scalable nested SEI messages with a sn_ols_flag equal to 0 are removed from outBitstream, and that no value of i in the range of 0 to nestingNumLayers-1 (inclusive) exists in the list nestingLayerId[i] in the list LayerIdInOls[targetOlsIdx].

[0132] 4) To solve problem 4, the condition "when LayerIdInOls[targetOlsIdx] does not include all values ​​of nuh_layer_id in all NAL units of the bitstream" is changed to "when the list LayerIdInOls[targetOlsIdx] does not include all values ​​of nuh_layer_id in all VCL NAL units of the bitstream inBitstream".

[0133] 5) To solve problem 5, a general sub-bit stream extraction process is defined, which extracts scalable nested SEI messages only from scalable nested SEI messages where sn_ols_flag is equal to 1 and sn_subpic_flag is equal to 0, in order to generate non-scalable nested SEI messages.

[0134] 6) To address problem 6, a general sub-bitstream extraction process is defined such that when multiple scalable nested SEI messages are extracted from a SEI NAL unit SeiNalUnitA as non-scalable nested SEI messages, they are still included in a SEI NAL unit seiNalUnitB in the output bitstream outBitstream, and the SEI NAL unit seiNalUnitB is included in the PU containing the SEI NAL unit SeiNalUnitA.

[0135] 7) To address problem 7, a general sub-bitstream extraction process is defined, which removes all SEI NAL units from the output bitstream outBitstream, from which some SEI messages have been extracted and included as non-scalable nested SEI messages.

[0136] a. Alternatively, remove the SEI NAL unit from outBitstream when the scalable nested SEI message in such a SEI NAL unit applies only to the target OLS (i.e., the targetOlsIdx OLS specified by the VPS).

[0137] b. Alternatively, remove the SEI NAL unit from outBitstream when there is no OLS containing all layers included in the list LayerIdInOls[targetOlsIdx] except for the target OLS in the OLS to which the scalable nested SEI message in this SEI NAL unit is applied.

[0138] 8) To solve problem 8, add a constraint that when the SEI NAL cell contains an SEI message with payloadType equal to 0, 1 or 130, the SEI NAL cell should not contain an SEI message with payloadType not equal to 0 (BP), 1 (PT), 130 (DUI) or 133 (scalable nesting).

[0139] 9) To address issue 9, the flag general_same_pic_timing_in_all_ols_flag specifies whether non-scalable nested PT and DUI SEI messages apply to all OLS.

[0140] a. Alternatively, the flag general_same_pic_timing_in_all_ols_flag specifies whether non-scalable nested BP, PT, and DUI SEI messages apply to all OLS.

[0141] i. In one example, the flag general_same_pic_timing_in_all_ols_flag is renamed to the flag general_same_pic_level_hrd_info_in_all_ols_flag, which specifies whether non-scalable nested BP, PT, and DUI SEI messages apply to all OLS.

[0142] b. Alternatively, add a new flag, such as named general_same_dui_in_all_ols_flag, to specify whether non-scalable nested DUI SEI messages apply to all OLS.

[0143] c. Alternatively, add a new flag, such as named general_same_bp_in_all_ols_flag, to specify whether non-scalable nested BP SEI messages apply to all OLS.

[0144] 6. Example

[0145] The following are some example embodiments of aspects of the invention summarized in Section 5 above, which can be applied to the VVC specification. The modified text is based on the latest VVC text in JVET-R2001-vA / v10. Most of the relevant additions or modifications are highlighted in bold and italics, and some deleted parts are marked with double brackets (e.g., [[a]] indicates the deletion of the character "a"). There may be other editable changes, which are not highlighted.

[0146] 6.1 First Embodiment

[0147] This embodiment applies to items 1, 2, 3, 3.a, 4, 5, 6, 7.b, and 8.

[0148] C6 General Sub-Bitstream Extraction Process

[0149] The inputs to this process are the bitstream inBitstream, the target OLS index targetOlsIdx, and the highest target TemporalId value tIdTarget.

[0150] The output of this process is the sub-bit stream outBitstream.

[0151] The requirement for bitstream consistency of the input bitstream is that any output sub-bitstream that satisfies all of the following conditions should be a consistent bitstream:

[0152] – The output sub-bitstream is the output of the procedure specified in this clause, where the bitstream targetOlsIdx is equal to the index of the OLS list specified by the VPS, and tIdTarget is equal to 0 to 1. Any value within the range (inclusive).

[0153] – The output sub-bitstream contains at least one VCL NAL unit, where nuh_layer_id is equal to each nuh_layer_id value in LayerIdInOls[targetOlsIdx].

[0154] – The output sub-bitstream contains at least one VCL NAL unit, where TemporalId is equal to tIdTarget.

[0155] Note – A consistent bitstream contains one or more codec stripe NAL units with TemporalId equal to 0, but not necessarily codec stripe NAL units with nuh_layer_id equal to 0.

[0156] To export the output sub-bitstream:

[0157] 1. The bitstream outBitstream is set to be the same as the bitstream inBitstream.

[0158] 2. Remove all NAL cells from outBitstream whose TemporalId is greater than tIdTarget.

[0159] 3. Remove nal_unit_type from outBitstream that is not equal to DCI_NUT.

[0160] VPS_NUT, And any of the EOB_NUTs, and nuh_layer_id is not included in all NAL units in the list LayerIdInOls[targetOlsIdx].

[0161] 4. Remove all VCL NAL units from outBitstream that satisfy all of the following conditions, and nal_unit_type is equal to PH_NUT or FD_NUT. SUFFIX_SEI_NUT PREFIX_SEI_NUT, Not equal to 0 (BP), 1 (PT), or 130 (DUI) The non-VCL NAL unit associated with the SEI message:

[0162] –nal_unit_type equals TRAIL_NUT, STSA_NUT, RADL_NUT, or RASL_NUT, or nal_unit_type equals GDR_NUT, and the associated ph_recovery_poc_cnt is not equal to 0.

[0163] –[[For j values ​​in the range of 0 to NumLayersInOls[targetOlsIdx]-1 (inclusive), nuh_layer_id is equal to LayerIdInOls[targetOlsIdx][j]]]

[0164] –temporal id is greater than or equal to NumSubLayersInLayerInOLS[targetOlsIdx][GeneralLayerIdx[nuh_layer_id]].

[0165] 5. Remove all SEI NAL units from outBitstream that contain scalable nested SEI messages with sn_ols_flag equal to 1 and no i value in the range from 0 to sn_num_olss_minus1 (inclusive), such that NestingOlsIdx[i] equals targetOlsIdx.

[0166]

[0167] 7. When LayerIdInOls[targetOlsIdx] does not include the bitstream. All When all values ​​of nuh_layer_id are in the NAL unit, the following are... Applicable to:

[0168] a. Remove all SEI NAL units from outBitstream that contain non-scalable nested SEI messages with payloadType equal to 0 (BP) or 130 (DUI).

[0169] b. When general_same_pic_timing_in_all_ols_flag equals 0, remove all SEI NAL cells from outBitstream that contain non-scalable nested SEI messages with payloadType equal to 1 (PT).

[0170] c. When outBitstream contains sn_ols_flag equal to 1 and The scalable nested SEI message's SEI NAL unit, which is applicable to the targetOlsIdx-th OLS (i.e., there is at least one i value in the range from 0 to sn_num_olss_minus1 (inclusive) such that NestingOlsIdx[i] equals targetOlsIdx), is as follows: Applicable to:

[0171] i. For each scalable nested BP or DUI SEI message in such a SEI NAL unit SeiNalUnitA outBitstream

[0172] ii. When general_same_pic_timing_in_all_ols_flag is equal to 0, for each scalable nested PT SEI message in such SEI NAL unit SeiNalUnitA, outBitstream .

[0173]

[0174] D.2.2 General SEI Payload Semantics ...

[0176] The following restrictions apply to the inclusion of SEI messages in SEINAL units and are requirements for bitstream consistency:

[0177] – When a SEINAL cell contains a non-scalable nested BP SEI message, a non-scalable nested PT SEI message, or a non-scalable nested DUI SEI message, the SEI NAL cell must not contain any other SEI message whose payload type is not equal to 0 (BP), 1 (PT), or 130 (DUI).

[0178] – When the SEI NAL cell contains a scalable nested BP SEI message, a scalable nested PT SEI message, or a scalable nested DUI SEI message, the SEI NAL cell should not contain any other SEI message with a payloadType that is not equal to 0 (BP), 1 (PT), 130 (DUI), or 133 (scalable nested).

[0179] – ...

[0181] Figure 1 This is a block diagram illustrating an example video processing system 1900, in which various techniques disclosed herein can be implemented. Various implementations may include some or all of the components of system 1900. System 1900 may include an input 1902 for receiving video content. The video content may be received in a raw or uncompressed format (e.g., 8- or 10-bit multi-component pixel values), or in a compressed or encoded format. Input 1902 may represent a network interface, a peripheral bus interface, or a storage interface. Examples of network interfaces include wired interfaces such as Ethernet, Passive Optical Networking (PON), etc., and wireless interfaces such as Wi-Fi or cellular interfaces.

[0182] System 1900 may include codec component 1904, which can implement the various encoding or codec methods described in this document. Codec component 1904 can reduce the average bit rate of the video from input 1902 to the output of codec component 1904 to produce a codec representation of the video. Therefore, codec techniques are sometimes referred to as video compression or video transcoding techniques. As indicated by component 1906, the output of codec component 1904 can be stored or transmitted via connected communication. Component 1908 can use the stored or transmitted bitstream (or codec) representation of the video received at input 1902 to generate pixel values ​​or displayable video sent to display interface 1910. The process of generating user-visible video from the bitstream representation is sometimes referred to as video decompression. Furthermore, although some video processing operations are referred to as “encoding” operations or tools, it should be understood that encoding tools or operations are used at the encoder, and corresponding decoding tools or operations, the opposite of the encoded result, are performed by the decoder.

[0183] Examples of peripheral bus interfaces or display interfaces may include Universal Serial Bus (USB), High Definition Multimedia Interface (HDMI), or DisplayPort. Examples of storage interfaces include SATA (Serial Advanced Technology Accessory), PCI, IDE, etc. The technologies described in this document can be implemented in a variety of electronic devices, such as mobile phones, laptops, smartphones, or other devices capable of performing digital data processing and / or video display.

[0184] Figure 2This is a block diagram of a video processing apparatus 3600. Apparatus 3600 can be used to implement one or more methods described herein. Apparatus 3600 can be embodied in smartphones, tablets, computers, Internet of Things (IoT) receivers, etc. Apparatus 3600 may include one or more processors 3602, one or more memories 3604, and video processing hardware 3606. Processor 3602 can be configured to implement one or more methods described in this document. Memory 3604 can be used to store data and code for implementing the methods and techniques described herein. Video processing hardware 3606 can be used to implement some of the techniques described in this document in hardware circuitry.

[0185] Figure 4 This is a block diagram illustrating an example video encoding / decoding system 100 that can utilize the technology of the present invention.

[0186] like Figure 4 As shown, the video encoding / decoding system 100 may include a source device 110 and a destination device 120. The source device 110 generates encoded video data, which may be referred to as a video encoding device. The destination device 120 decodes the encoded / decoded video data generated by the source device 110, and may be referred to as a video decoding device.

[0187] The source device 110 may include a video source 112, a video encoder 114, and an input / output (I / O) interface 116.

[0188] Video source 112 may include sources such as video capture devices, interfaces for receiving video data from video content providers, and / or computer graphics systems for generating video data, or combinations thereof. Video data may include one or more pictures. Video encoder 114 encodes the video data from video source 112 to generate a bitstream. The bitstream may include a sequence of bits forming an encoded representation of the video data. The bitstream may include encoded pictures and associated data. The encoded pictures are an encoded representation of the pictures. The associated data may include sequence parameter sets, picture parameter sets, and other syntax structures. I / O interface 116 may include a modulator / demodulator (modem) and / or a transmitter. Encoded video data may be transmitted directly to destination device 120 via network 130a through I / O interface 116. Encoded video data may also be stored on storage media / server 130b for access by destination device 120.

[0189] Destination device 120 may include I / O interface 126, video decoder 124 and display device 122.

[0190] I / O interface 126 may include a receiver and / or a modem. I / O interface 126 may acquire encoded video data from source device 110 or storage medium / server 130b. Video decoder 124 may decode the encoded video data. Display device 122 may display the decoded video data to a user. Display device 122 may be integrated with destination device 120, or it may be external to destination device 120, which is configured to interface with an external display device.

[0191] The video encoder 114 and the video decoder 124 can operate according to video compression standards such as the High Efficiency Video Codec (HEVC) standard, the Universal Video Codec (VVC) standard, and other current and / or further standards.

[0192] Figure 5 This is a block diagram illustrating an example of a video encoder 200, which may be... Figure 4 The video encoder 114 in the system 100 shown.

[0193] The video encoder 200 can be configured to perform any or all of the technologies disclosed herein. Figure 5 In the example, the video encoder 200 includes multiple functional components. The techniques described in this invention can be shared among the various components of the video encoder 200. In some examples, the processor can be configured to perform any or all of the techniques described in this disclosure.

[0194] The functional components of the video encoder 200 may include a segmentation unit 201, a prediction unit 202 (including a mode selection unit 203), a motion estimation unit 204, a motion compensation unit 205, an intra-frame prediction unit 206, a residual generation unit 207, a transform unit 208, a quantization unit 209, an inverse quantization unit 210, an inverse transform unit 211, a reconstruction unit 212, a buffer 213, and an entropy coding unit 214.

[0195] In other examples, the video encoder 200 may include more, fewer, or different functional components. In one example, the prediction unit 202 may include an intra-block copy (IBC) unit. The IBC unit can perform prediction in IBC mode, where at least one reference picture is the picture containing the current video block.

[0196] Furthermore, some components, such as the motion estimation unit 204 and the motion compensation unit 205, can be highly integrated, but for illustrative purposes, in Figure 5 The examples are shown separately.

[0197] The segmentation unit 201 can segment an image into one or more video blocks. The video encoder 200 and the video decoder 300 can support various video block sizes.

[0198] The mode selection unit 203 can select one of the encoding / decoding modes, such as intra-frame or inter-frame, based on the error result, and provide the resulting intra-frame or inter-frame encoded / decoded blocks to the residual generation unit 207 to generate residual block data, and provide it to the reconstruction unit 212 to reconstruct the encoded blocks as reference images. In some examples, the mode selection unit 203 can select a combination of intra-frame and inter-frame prediction (CIIP) modes, where prediction is based on inter-frame prediction signals and intra-frame prediction signals. In the case of inter-frame prediction, the mode selection unit 203 can also select the precision of the motion vectors for the blocks (e.g., sub-pixel or integer pixel precision).

[0199] To perform inter-frame prediction on the current video block, motion estimation unit 204 can generate motion information for the current video block by comparing one or more reference frames from buffer 213 with the current video block. Motion compensation unit 205 can determine the predicted video block for the current video block based on motion information from images other than those associated with the current video block from buffer 213 and decoded samples.

[0200] The motion estimation unit 204 and the motion compensation unit 205 can perform different operations on the current video block, for example, depending on whether the current video block is in an I-band, P-band, or B-band.

[0201] In some examples, motion estimation unit 204 can perform unidirectional prediction on the current video block, and can search for a reference video block for the current video block in reference images in list 0 or list 1. Motion estimation unit 204 can then generate a reference index indicating the reference image in list 0 or list 1, the reference image containing the reference video block and a motion vector indicating the spatial displacement between the current video block and the reference video block. Motion estimation unit 204 can output the reference index, prediction direction indicator, and motion vector as motion information for the current video block. Motion compensation unit 205 can generate a predicted video block for the current block based on the reference video block indicated by the motion information of the current video block.

[0202] In other examples, motion estimation unit 204 can perform bidirectional prediction on the current video block. Motion estimation unit 204 can search for a reference video block for the current video block in the reference images in list 0, and can also search for another reference video block for the current video block in the reference images in list 1. Motion estimation unit 204 can then generate a reference index and a motion vector. The reference index indicates the reference images in lists 0 and 1 that contain the reference video block, and the motion vector indicates the spatial displacement between the reference video block and the current video block. Motion estimation unit 204 can output the reference index and motion vector of the current video block as motion information for the current video block. Motion compensation unit 205 can generate a predicted video block for the current video block based on the reference video block indicated by the motion information of the current video block.

[0203] In some examples, the motion estimation unit 204 can output a complete set of motion information for the decoder's decoding processing.

[0204] In some examples, motion estimation unit 204 may not output the complete set of motion information for the current video. Instead, motion estimation unit 204 may signal the motion information of the current video block to another video block by referring to the motion information of that other video block. For example, motion estimation unit 204 may determine that the motion information of the current video block is sufficiently similar to the motion information of neighboring video blocks.

[0205] In one example, the motion estimation unit 204 may indicate a value in the syntax structure associated with the current video block that indicates to the video decoder 300 that the current video block has the same motion information as another video block.

[0206] In another example, motion estimation unit 204 may identify another video block and motion vector difference (MVD) in the syntax structure associated with the current video block. The motion vector difference indicates the difference between the motion vector of the current video block and the motion vector of the indicated video block. Video decoder 300 can use the motion vector of the indicated video block and the motion vector difference to determine the motion vector of the current video block.

[0207] As described above, the video encoder 200 can predictively signal motion vectors. Two examples of predictive signaling techniques that can be implemented by the video encoder 200 include Advanced Motion Vector Prediction (AMVP) and Combined Mode Signaling.

[0208] Intra-prediction unit 206 can perform intra-prediction on the current video block. When intra-prediction unit 206 performs intra-prediction on the current video block, it can generate prediction data for the current video block based on the decoded samples of other video blocks in the same frame. The prediction data for the current video block may include the predicted video block and various syntax elements.

[0209] The residual generation unit 207 can generate residual data for the current video block by subtracting (e.g., indicated by a negative sign) one or more predicted video blocks from the current video block. The residual data for the current video block may include residual video blocks corresponding to different sample components of the samples in the current video block.

[0210] In other examples, the current video block may not have residual data, such as in skip mode, and the residual generation unit 207 may not perform the subtraction operation.

[0211] Transform unit 208 can generate one or more transform coefficient video blocks of the current video block by applying one or more transforms to the residual video block associated with the current video block.

[0212] After the transform unit 208 generates a transform coefficient video block associated with the current video block, the quantization unit 209 can quantize the transform coefficient video block associated with the current video block based on one or more quantization parameter (QP) values ​​associated with the current video block.

[0213] Inverse quantization unit 210 and inverse transform unit 211 can apply inverse quantization and inverse transform to the transform coefficient video block, respectively, to reconstruct the residual video block from the transform coefficient video block. Reconstruction unit 212 can add the reconstructed residual video block to the corresponding samples from one or more predicted video blocks generated by prediction unit 202 to produce a reconstructed video block associated with the current block, which is then stored in buffer 213.

[0214] After the video block is reconstructed by reconstruction unit 212, a loop filtering operation can be performed to reduce video block artifacts.

[0215] Entropy encoding unit 214 can receive data from other functional components of video encoder 200. When entropy encoding unit 214 receives data, it can perform one or more entropy encoding operations to generate entropy-encoded data and output a bitstream including the entropy-encoded data.

[0216] Figure 6 This is a block diagram illustrating an example of a video decoder 300, which may be... Figure 4 The video decoder 124 in the system 100 shown.

[0217] The video decoder 300 can be configured to perform any or all of the techniques of this invention. Figure 5 In the example, the video decoder 300 includes multiple functional components. The techniques described in this disclosure can be shared among the various components of the video decoder 300. In some examples, the processor can be configured to perform any or all of the techniques described in this disclosure.

[0218] exist Figure 6 In the example, the video decoder 300 includes an entropy decoding unit 301, a motion compensation unit 302, an intra-frame prediction unit 303, an inverse quantization unit 304, an inverse transform unit 305, a reconstruction unit 306, and a buffer 307. In some examples, the video decoder 300 can perform functions typically associated with the video encoder 200. Figure 5 The decoding process is the inverse of the encoding process described.

[0219] The entropy decoding unit 301 can retrieve the encoded bitstream. The encoded bitstream may include entropy-coded video data (e.g., encoded blocks of video data). The entropy decoding unit 301 can decode the entropy-coded video data, and from the entropy-decoded video data, the motion compensation unit 302 can determine motion information, including motion vectors, motion vector precision, reference image list index, and other motion information. The motion compensation unit 302 may determine this information, for example, by performing AMVP and merging modes.

[0220] The motion compensation unit 302 can generate blocks of motion compensation, possibly performing interpolation based on an interpolation filter. The syntax elements may include identifiers of the interpolation filter to be used with sub-pixel precision.

[0221] The motion compensation unit 302 can use interpolation filters, such as those used by the video encoder 200 during the encoding of a video block, to calculate interpolated values ​​for sub-integer pixels of the reference block. The motion compensation unit 302 can determine the interpolation filter used by the video encoder 200 based on the received syntax information and use the interpolation filter to generate a prediction block.

[0222] The motion compensation unit 302 may use some syntax information to determine the size of the blocks of (one or more) frames and / or (one or more) stripes of the video sequence used for encoding, segmentation information describing how each macroblock of the picture of the encoded video sequence is segmented, a mode indicating how each segment is encoded, one or more reference frames (and a list of reference frames) of the blocks encoded between each frame, and other information for decoding the encoded video sequence.

[0223] Intra-prediction unit 303 can use, for example, an intra-prediction mode received in the bitstream to form prediction blocks from spatially adjacent blocks. Inverse quantization unit 304 inverse quantizes (i.e., dequantizes) the quantized video block coefficients provided in the bitstream and decoded by entropy decoding unit 301. Inverse transform unit 305 applies the inverse transform.

[0224] The reconstruction unit 306 can add the residual block to the corresponding prediction block generated by the motion compensation unit 302 or the intra-frame prediction unit 303 to form a decoded block. If necessary, a deblocking filter can also be applied to filter the decoded block to remove block artifacts. The decoded video block is then stored in a buffer 307, which provides a reference block for subsequent motion compensation / intra-frame prediction and also generates the decoded video for presentation on the display device.

[0225] The solution list describes some embodiments of the disclosed technology.

[0226] The first set of solutions is presented below. The following solutions illustrate example embodiments of the techniques discussed in the previous section (e.g., items 1-9).

[0227] 1. A method for video processing (e.g., Figure 3 Method 600 in the example includes performing (602) a conversion between a video comprising one or more video layers and a video codec representation, the one or more video layers comprising one or more video pictures, wherein the codec representation conforms to format rules associated with the extraction of sub-bitstreams from the codec representation.

[0228] 2. The method of Solution 1 also includes: extracting sub-bit streams from the encoded and decoded representations according to format rules.

[0229] The following solutions show example embodiments of the techniques discussed in the previous section (e.g., item 1).

[0230] 3. The method of any one of solutions 1-2, wherein, during the extraction of sub-bit streams, the target id for extraction is allowed to be in the range of 0 to the value of the syntax field indicated in the video parameter set for the representation used for encoding and decoding.

[0231] The following solutions illustrate example embodiments of the techniques discussed in the previous section (e.g., item 2).

[0232] 4. The method of any one of solutions 1-3, wherein the sub-bitstream is extracted without removing the Access Unit Delimiter Network Abstraction Layer (AUD NAL) from the output bitstream based on the layer ID.

[0233] The following solutions illustrate example embodiments of the techniques discussed in the previous section (e.g., item 3).

[0234] 5. The method of any one of solutions 1-4, wherein a sub-bitstream is extracted by selectively removing network abstraction layer units, said network abstraction layer units including scalable nested supplementary enhancement information messages that are not applicable to the output layer being extracted.

[0235] The following solutions illustrate example embodiments of the techniques discussed in the previous section (e.g., item 5).

[0236] 6. The method of any one of solutions 1-5, wherein the sub-bitstream is extracted by constraining the extraction to generate non-scalable nested supplementary enhancement information (SEI) from scalable nested supplementary enhancement information (SEI) messages by setting a flag for the output layer set and disabling a flag for sub-pictures.

[0237] The following solutions show example embodiments of the techniques discussed in the previous section (e.g., item 6).

[0238] 7. The method of any one of solutions 1-6, wherein the sub-bit stream is extracted according to a rule specifying the extraction of multiple scalable nested supplementary enhancement information (SEI) messages from a single SEI network abstraction layer unit.

[0239] The following solutions show example embodiments of the techniques discussed in the previous section (e.g., item 7).

[0240] 8. The method of any one of solutions 1-7, wherein a sub-bit stream is extracted according to a rule for removing all Supplemental Enhanced Information Network Abstraction Layer (SEI) NAL units from the encoded and decoded representation, some SEI messages having been extracted from the SEI units and included as non-scalable nested SEI messages.

[0241] The following solutions show example embodiments of the techniques discussed in the previous section (e.g., item 8).

[0242] 9. The method of any one of solutions 1-8, wherein the format rule specifies that when a Supplemental Enhanced Information Network Abstraction Layer (SEI NAL) unit contains an SEI message with payloadType equal to 0, 1, or 130, the SEI NAL unit is not allowed to contain SEI messages with payloadType not equal to 0 (BP), 1 (PT), 130 (DUI), or 133 (Scalable Nested).

[0243] 10. The method of any one of solutions 1-9, wherein performing the conversion includes encoding and decoding the video into an encoded and decoded representation.

[0244] 11. The method of any one of solutions 1-9, wherein performing the conversion includes parsing and decoding the encoded / decoded representation to generate a video.

[0245] 12. A video decoding apparatus, comprising a processor configured to implement the method described in one or more of solutions 1 to 11.

[0246] 13. A video encoding apparatus, comprising a processor configured to implement the method described in one or more of solutions 1 to 11.

[0247] 14. A computer program product having computer code stored thereon, which, when executed by a processor, causes the processor to implement the method of any one of solutions 1 to 11.

[0248] 15. The methods, apparatus or systems described in this document.

[0249] The second set of solutions shows example embodiments of the techniques discussed in the previous section (e.g., items 1, 4, 8, and 9).

[0250] 1. A method for video processing (e.g., such as...) Figure 7A The method 700 shown includes: performing 702 a conversion between multi-layered video and video bitstreams according to a rule, wherein the rule specifies the maximum allowed value of the temporal layer identifier value of the sub-bitstream extracted from the bitstream.

[0251] 2. The method of Solution 1, wherein the rule responds to the number of layers in the bitstream.

[0252] 3. The method of Solution 1 or 2, wherein, when the number of layers is greater than 1, the rule specifies that the maximum allowed value of the temporal layer identifier is in the range of 0 to the value of the first syntax element in the video parameter set based on the bitstream reference.

[0253] 4. The method of solution 1 or 2, wherein, when the number of layers is equal to 1, the rule specifies that the maximum allowed value of the time-domain layer identifier is in the range of 0 to the value of the second syntax element in the sequence parameter set referenced by the bitstream.

[0254] 5. The method of Solution 3, wherein the first syntax element specifies the maximum number of temporal sublayers allowed to exist in the layer specified by the video parameter set minus 1.

[0255] 6. The approach of Solution 4, wherein the second syntax element specifies the maximum number of temporal sublayers allowed to exist in the layer specified by the sequence parameter set minus 1.

[0256] 7. The method of Solution 3, wherein the first syntax element in the video parameter set is vps_max_sublayers_minus1.

[0257] 8. The method of Solution 4, wherein the second syntax element in the sequence parameter set is sps_max_sublayers_minus1.

[0258] 9. The method of solution 3 or 4, wherein the value is equal to the value of the first syntax element or the second syntax element.

[0259] 10. A method for video processing (e.g., such as...) Figure 7B The method 710 shown includes: performing a conversion between a video and a video bitstream according to a rule 712, wherein the rule defines the Network Abstraction Layer (NAL) units to be extracted from the bitstream during the sub-bitstream extraction process to output a sub-bitstream, and wherein the rule specifies that the sub-bitstream is derived based on whether the list of NAL unit header identifier values ​​in the Output Layer Set (OLS) with the target OLS index does not include all values ​​of the NAL unit header identifiers in all Video Codec Layer (VCL) NAL units in the bitstream input to the sub-bitstream extraction process.

[0260] 11. The method of Solution 10, wherein, in the case that the list of NAL unit header identifier values ​​in the output layer set does not include all values ​​of the NAL unit header identifier in all VCL NAL units in the bitstream, the rule specifies the removal from the sub-bitstream of all Supplemental Enhancement Information (SEI) NAL units containing non-scalable nested SEI messages with payload type equal to 0 or 130.

[0261] 12. A method for video processing (e.g., Figure 7C The method 720 shown includes: performing a conversion between a video and a video bitstream according to a rule 722, wherein the rule defines a Network Abstraction Layer (NAL) unit to be extracted from the bitstream during the sub-bitstream extraction process to output a sub-bitstream, and wherein the rule specifies that, in response to the payload type of a first Supplemental Enhancement Information (SEI) message included in the SEI Network Abstraction Layer (NAL) unit, the SEI NAL unit is prohibited from containing an SEI message with a specific payload type.

[0262] 13. The method of Solution 12, wherein the payload type of the first SEI message is 0, 1 or 130, and the rule stipulates that SEI NAL units are not allowed to contain SEI messages with a specific payload type that is not equal to 0, 1, 130 or 133.

[0263] 14. A method for video processing (e.g., such as...) Figure 7D The method shown (730) includes: performing a conversion between 732 video and video bitstreams according to format rules, wherein the format rules specify that the bitstreams include flags indicating whether one or more non-scalable nested supplementary enhancement information (SEI) messages of one or more specific payload types are applied to all output layer sets of the codec layer reference.

[0264] 15. The method of Solution 14, wherein one or more specific payload types are equal to 1 and 130.

[0265] 16. The method of Solution 14, wherein one or more non-scalable SEI messages are Picture Timing (PT) SEI messages and Decoding Unit Information (DUI) SEI messages.

[0266] 17. The method of Solution 14, wherein one or more specific payload types are equal to 0, 1, and 130.

[0267] 18. The method of Solution 14, wherein one or more non-scalable SEI messages are buffer period (BP) SEI messages and decode unit information (DUI) SEI messages.

[0268] 19. The method of Solution 14, wherein one or more specific payload types are equal to 130.

[0269] 20. The method of Solution 14, wherein one or more non-scalable SEI messages are Decoding Unit Information (DUI) SEI messages.

[0270] 21. The method of Solution 14, wherein one or more specific payload types are equal to 0.

[0271] 22. The method of Solution 1, wherein one or more non-scalable SEI messages are buffered (BP) SEI messages.

[0272] 23. The method of any one of solutions 1 to 22, wherein the conversion includes encoding and decoding the video into a bitstream.

[0273] 24. The method of any one of solutions 1 to 22, wherein the conversion includes decoding video from the bitstream.

[0274] 25. The method of any one of solutions 1 to 22, wherein the conversion includes generating a bitstream from video, and the method further includes storing the bitstream in a non-transitory computer-readable recording medium.

[0275] 26. A video processing apparatus comprising a processor configured to implement the method described in any one or more of solutions 1 to 25.

[0276] 27. A method for storing a bitstream of video, comprising the method of any one of solutions 1 to 25, and further comprising storing the bitstream to a non-transitory computer-readable recording medium.

[0277] 28. A computer-readable medium storing program code that, when executed, causes a processor to implement the method described in any one or more of solutions 1 to 25.

[0278] 29. A computer-readable medium for storing a bit stream generated according to any of the above methods.

[0279] 30. A video processing apparatus for storing a bitstream representation, wherein the video processing apparatus is configured to implement the method described in any one or more of solutions 1 to 25.

[0280] The third set of solutions shows example embodiments of the techniques discussed in the previous section (e.g., item 2).

[0281] 1. A method for video processing (e.g., such as...) Figure 8 The method 800 shown includes: performing a conversion between 802 video and video bitstream according to a rule, wherein the rule specifies a sub-bitstream extraction process by which an output sub-bitstream is extracted from the bitstream without removing NAL units of a specific type and having a specific Network Abstraction Layer (NAL) unit header identifier value, wherein the specific type includes Access Unit Delimiter (AUD) NAL units.

[0282] 2. The approach of Solution 1, wherein the specific type includes Video Parameter Set (VPS) NAL units.

[0283] 3. The method of Solution 1 or 2, wherein a specific type includes a decoding capability information NAL unit.

[0284] 4. The method of any one of solutions 1-3, wherein the specific type includes the bitstream end NAL unit.

[0285] 5. The method of any one of solutions 1-4, wherein a particular type includes a supplemental enhancement information NAL unit, the supplemental enhancement information unit containing a non-scalable nested SEI message having a payload type equal to 0, 1, 130 or 203.

[0286] 6. The method of any one of solutions 1-6, wherein the specific NAL cell header identifier value includes a layer identifier value, which is included in the layer value list of the output sub-bitstream.

[0287] 7. The method of Solution 1, wherein the rule stipulates that a specific type of NAL cell shall not be removed from the output bitstream based on an exception, regardless of the NAL cell header identifier value associated with the specific type of NAL cell.

[0288] 8. The method of any one of solutions 1 to 7, wherein the conversion includes encoding the video into a bitstream.

[0289] 9. The method of any one of solutions 1 to 7, wherein the conversion includes decoding video from the bitstream.

[0290] 10. The method of any one of solutions 1 to 7, wherein the conversion includes generating a bitstream from video, and the method further includes storing the bitstream in a non-transitory computer-readable recording medium.

[0291] 11. A video processing apparatus comprising a processor configured to implement the method described in any one or more of solutions 1 to 10.

[0292] 12. A method for storing a bitstream of video, comprising the method of any one of solutions 1 to 10, and further comprising storing the bitstream to a non-transitory computer-readable recording medium.

[0293] 13. A computer-readable medium storing program code that, when executed, causes a processor to implement the method described in any one or more of solutions 1 to 10.

[0294] 14. A computer-readable medium for storing a bit stream generated according to any of the above methods.

[0295] 15. A video processing apparatus for storing a bitstream representation, wherein the video processing apparatus is configured to implement the method described in any one or more of solutions 1 to 10.

[0296] The fourth set of solutions shows example embodiments of the techniques discussed in the previous section (e.g., item 3).

[0297] 1. A method for video processing (e.g., such as...) Figure 9 The method 900 shown includes: performing 902 a conversion between a video comprising one or more layers and a bitstream of the video according to a rule, wherein the rule specifies the removal of Network Abstraction Layer (NAL) units including Scalable Nested Supplementary Enhancement Information (SEI) messages during sub-bitstream extraction, which are applied to layers not included in the target output layer set (OLS).

[0298] 2. The method of Solution 1, wherein the scalable nested SEI message is associated with a flag having a value equal to the specific value to which the scalable nested SEI message is applied to the layer.

[0299] 3. The method of Solution 2, where the specific value is 0.

[0300] 4. The method of Solution 1, wherein the rule further specifies the removal of NAL units of SEI messages that have no value in the first list (NestingLayerID[i]) included in the second list (LayerIdInOls[targetOlsIdx]), whereby the first list specifies the NAL unit header identifier value of the layer to which the scalable nested SEI message is applied, and I is in the range of 0 to NumLayers-1, where NumLayers indicates the number of layers to which the scalable nested SEI message is applied, and the second list specifies the NAL unit header identifier value in the target output layer set with the target output layer index.

[0301] 5. The method of any one of solutions 1 to 4, wherein the conversion includes encoding the video into a bitstream.

[0302] 6. The method of any one of solutions 1 to 4, wherein the conversion includes decoding video from the bitstream.

[0303] 7. The method of any one of solutions 1 to 4, wherein the conversion includes generating a bitstream from video, and the method further includes storing the bitstream in a non-transitory computer-readable recording medium.

[0304] 8. A video processing apparatus comprising a processor configured to implement the method described in any one or more of solutions 1 to 7.

[0305] 9. A method for storing a bitstream of video, comprising the method of any one of solutions 1 to 7, and further comprising storing the bitstream to a non-transitory computer-readable recording medium.

[0306] 10. A computer-readable medium storing program code that, when executed, causes a processor to implement the method described in any one or more of solutions 1 to 7.

[0307] 11. A computer-readable medium for storing a bit stream generated according to any of the above methods.

[0308] 12. A video processing apparatus for storing a bitstream representation, wherein the video processing apparatus is configured to implement the method described in any one or more of solutions 1 to 7.

[0309] The fifth set of solutions illustrates example embodiments of the techniques discussed in the previous section (e.g., items 5-7).

[0310] 1. A method for video processing (e.g., such as...) Figure 10AThe method 1000 shown includes: performing 1002 a conversion between a video comprising one or more layers and a bitstream of the video according to a rule, wherein the rule specifies that, during sub-bitstream extraction, a non-scalable nested SEI message is generated by extracting a scalable nested SEI message from scalable nested SEI messages based on a first flag indicating whether a Supplemental Enhancement Information (SEI) message is applied to a specific Output Layer Set (OLS) and a second flag indicating whether the SEI message is applied to all sub-pictures or only to a specific sub-picture.

[0311] 2. The method of Solution 1, wherein the rule specifies that a non-scalable nested SEI message is generated in response to the following conditions: i) a first flag has a first value specifying that the SEI message is applied to a particular output layer set (OLS), and ii) a second flag has a second value specifying that the SEI message applied to a particular OLS is applied to all subgraphs of the specified OLS that are satisfied.

[0312] 3. A method for video processing (e.g., such as...) Figure 10B The method 1010 shown includes: performing 1012 a conversion between a video comprising one or more layers and a bitstream of the video according to a rule, wherein the rule specifies that, during the sub-bitstream extraction process, a non-scalable nested SEI message is generated by extracting multiple scalable nested supplementary enhancement information (SEI) messages from a first supplementary enhancement information (SEI) network abstraction layer (NAL) unit in the picture unit.

[0313] 4. The method of Solution 3, wherein multiple scalable nested SEI messages are included in a second SEINAL unit included in the picture unit.

[0314] 5. The method of Solution 4, wherein the second SEI NAL unit is immediately following the first SEI NAL unit.

[0315] 6. A method for video processing (e.g., such as...) Figure 10C The method 1020 shown includes: performing a conversion between a video comprising one or more layers and a bitstream of the video according to a rule 1022, wherein the rule specifies a sub-bitstream extraction process to generate an output bitstream, wherein the rule specifies processing of one or more Supplemental Enhancement Information (SEI) Network Abstraction Layer (NAL) units during the sub-bitstream extraction process.

[0316] 7. The method of Solution 6, wherein the rule specifies the removal of one or more SEI NAL units from which some SEI messages have been extracted and included as non-scalable nested SEI messages.

[0317] 8. The approach of Solution 6, wherein the rule specifies the removal of SEINAL units containing scalable nested SEI messages that apply only to the target output layer set.

[0318] 9. The method of Solution 6, wherein the rule specifies the removal of SEI NAL units containing scalable nested SEI messages, the scalable nested SEI messages being applied to an output layer set (OLS) in which there are no OLSs other than the target OLS.

[0319] 10. The method of any one of solutions 1 to 9, wherein the conversion includes encoding the video into a bitstream.

[0320] 11. The method of any one of solutions 1 to 9, wherein the conversion includes decoding video from the bitstream.

[0321] 12. The method of any one of solutions 1 to 9, wherein the conversion includes generating a bitstream from video, and the method further includes storing the bitstream in a non-transitory computer-readable recording medium.

[0322] 13. A video processing apparatus comprising a processor configured to implement the method described in any one or more of solutions 1 to 12.

[0323] 14. A method for storing a bitstream of video, comprising the method of any one of solutions 1 to 12, and further comprising storing the bitstream to a non-transitory computer-readable recording medium.

[0324] 15. A computer-readable medium storing program code that, when executed, causes a processor to implement the method described in any one or more of solutions 1 to 12.

[0325] 16. A computer-readable medium for storing a bit stream generated according to any of the methods described above.

[0326] 17. A video processing apparatus for storing a bitstream representation, wherein the video processing apparatus is configured to implement the method described in any one or more of solutions 1 to 12.

[0327] The disclosed and other solutions, examples, embodiments, modules, and functional operations described herein can be implemented in digital electronic circuits, or in computer software, firmware, or hardware, including the structures disclosed herein and their structural equivalents, or in combinations of one or more of them. The disclosed and other embodiments can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer-readable medium for execution by or control of the operation of a data processing apparatus. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a storage device, a combination of materials that implement machine-readable propagating signals, or a combination of one or more of them. The term "data processing apparatus" includes all means, devices, and machines for processing data, including, for example, a programmable processor, a computer, or multiple processors or computers. In addition to hardware, the apparatus may include code that creates an execution environment for the computer program in question, for example, code constituting processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. Propagating signals are artificially generated signals, such as machine-generated electrical, optical, or electromagnetic signals, which are generated to encode information for transmission to a suitable receiving device.

[0328] Computer programs (also known as programs, software, software applications, scripts, or code) can be written in any programming language, including compiled or interpreted languages, and can be deployed in any form, including as standalone programs or as modules, components, subroutines, or other units suited to a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored as a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple collaborative files (e.g., a file storing one or more modules, subroutines, or code sections). Computer programs can be deployed to execute on a single computer or on multiple computers located in one place or distributed across multiple locations and interconnected via a communication network.

[0329] The processes and logic flows described herein can be executed by one or more programmable processors that execute one or more computer programs to perform functions by manipulating input data and generating outputs. The processes and logic flows can also be executed by dedicated logic circuits, and the devices can be implemented as dedicated logic circuits, such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits).

[0330] For example, processors suitable for executing computer programs include general-purpose and special-purpose microprocessors, as well as any one or more processors in any kind of digital computer. Typically, the processor receives instructions and data from read-only memory or random access memory, or both. The basic components of a computer are a processor for executing instructions and one or more storage devices for storing instructions and data. Typically, a computer will also include, or be operatively coupled to, one or more mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks, to receive data from or transfer data to, or both. However, a computer does not need to have such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and storage devices, including, for example, semiconductor storage devices such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD-ROMs and DVD-ROMs. The processor and memory may be supplemented or incorporated therein by dedicated logic circuitry.

[0331] While this patent document contains numerous details, these details should not be construed as limiting the scope of any subject matter or claimed content, but rather as descriptions of features characteristic of specific embodiments of a particular technology. Certain features described in the context of independent embodiments in this patent document may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments. Furthermore, although features may be described above as functioning in certain combinations, and even initially claimed in this way, one or more features from a claimed combination may be removed from that combination in some cases, and the claimed combination may be for sub-combinations or variations thereof.

[0332] Similarly, although operations are described in a specific order in the accompanying drawings, this should not be construed as requiring these operations to be performed in the specific order or sequence shown, or requiring all illustrated operations to be performed to obtain the desired result. Furthermore, the separation of various system components in the embodiments described in this patent document should not be construed as requiring such separation in all embodiments.

[0333] Only some implementation methods and examples are described, and other implementation methods, enhancements and variations can be made based on the content described and shown in this patent document.

Claims

1. A video processing method, comprising: Perform the conversion between the video and the video bitstream according to the rules. The rules specify a sub-bitstream extraction process, through which an output sub-bitstream is extracted from the bitstream without removing NAL units of a specific type that have a specific Network Abstraction Layer (NAL) unit header identifier value. The specific type includes Access Element Delimiter (AUD) NAL units. The rule states that regardless of the NAL unit header identifier value associated with a particular type of NAL unit, the particular type of NAL unit will not be removed from the output sub-bitstream.

2. The method according to claim 1, wherein, The specific type includes the Video Parameter Set (VPS) NAL unit.

3. The method according to claim 1 or 2, wherein, The specific type includes the decoding capability information NAL unit.

4. The method according to claim 1 or 2, wherein, The specific type includes the bitstream end-of-line NAL unit.

5. The method according to claim 1 or 2, wherein, The specific type includes a Supplemental Enhancement Information (NAL) unit, which contains a non-scalable nested SEI message with a payload type equal to 0, 1, 130, or 203.

6. The method according to claim 1 or 2, wherein, The specific NAL unit header identifier value includes a layer identifier value, which is included in the layer value list of the output sub-bitstream.

7. The method according to claim 1 or 2, wherein, The conversion includes encoding the video into the bitstream.

8. The method according to claim 1 or 2, wherein, The conversion includes decoding the video from the bitstream.

9. The method according to claim 1 or 2, wherein, The conversion includes generating the bitstream from the video, and the method further includes storing the bitstream in a non-transitory computer-readable recording medium.

10. A video processing apparatus comprising a processor configured to implement the method of any one of claims 1 to 9.

11. A method for storing a video bitstream, comprising: The method of any one of claims 1 to 8 is used to generate a bit stream and to store the bit stream in a non-transitory computer-readable recording medium.

12. A computer-readable medium storing program code, which, when executed, causes a processor to implement the method according to any one of claims 1 to 9.

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