Processing of supplemental enhancement information in subpicture sub-bitstream extraction process

Abstract

A method of video data processing includes performing a conversion between a video and a video bitstream. The bitstream includes one or more layers, the layer includes one or more pictures, the picture includes one or more sub-pictures, and a rule specifies a selective processing of first supplemental enhancement information network abstraction layer (SEI) NAL units of a target output sub-picture sub-bitstream extracted during a sub-picture sub-bitstream extraction process in response to a condition.

Description

[0001] Cross-references to related applications

[0002] This application is an application filed on June 8, 2021, under International Patent Application No. PCT / US2021 / 036369, which entered the Chinese national phase. This application aims to promptly claim priority to U.S. Provisional Patent Application No. 63 / 036,908, filed on June 9, 2020. The entire disclosure of the above applications is incorporated herein by reference and forms part of this application. Technical Field

[0003] This patent document relates to image and video data processing. 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 process encoded or decoded representations of video or images.

[0006] In one representative aspect, a method for processing video data is disclosed. The method includes: performing a conversion between a video and a bitstream of the video, wherein, according to a rule, the bitstream comprises multiple layers, each layer comprising one or more sub-pictures; wherein the rule specifies that, during a sub-picture bitstream extraction process to extract an output bitstream from the bitstream, a Supplemental Enhanced Information Network Abstraction Layer (SEI NAL) unit is omitted from the output bitstream, the SEI unit comprising scalable nested SEI messages not applicable to the output bitstream.

[0007] In one representative aspect, a method for processing video data is disclosed. The method includes: performing a conversion between a video and a bitstream of the video, wherein, according to a rule, the bitstream comprises multiple layers, each layer comprising one or more images, and each image comprising one or more sub-images; wherein the rule specifies that a first sub-image index identifying a sequence of sub-images extracted from the bitstream by a sub-image sub-bitstream extraction process, and a second sub-image index based on a layer of the bitstream having multiple sub-images per image.

[0008] In one representative aspect, a method for processing video data is disclosed. The method includes: performing a conversion between a video and a bitstream of the video, wherein, according to rules, the bitstream comprises one or more layers, each layer comprises one or more sub-layers, each sub-layer comprises one or more pictures, and each picture comprises one or more sub-pictures, wherein the rules specify a rewrite operation selectively performed on one or more syntax structures during a sub-picture sub-bitstream extraction process from the bitstream to extract an output target sub-bitstream, wherein the one or more syntax elements include information about the output target sub-bitstream.

[0009] In one representative aspect, a method for processing video data is disclosed. The method includes: performing a conversion between a video and a bitstream of the video, wherein the bitstream comprises one or more layers according to a rule, the layers comprise one or more pictures, the pictures comprise one or more sub-pictures, wherein the rule specifies selective processing of a first Supplemental Enhanced Information Network Abstraction Layer (SEI NAL) unit of a target output sub-picture sub-bitstream extracted during a sub-picture sub-bitstream extraction process in response to conditions.

[0010] In yet another representative aspect, a video encoding apparatus is disclosed. This video encoding apparatus includes a processor configured to perform the methods described above.

[0011] In another representative aspect, a video decoding apparatus is disclosed. This video decoding apparatus includes a processor configured to perform the methods described above.

[0012] In another representative aspect, a computer-readable medium having code stored thereon is disclosed. This code embodies one of the methods described herein in the form of processor-executable code.

[0013] These and other features are described in this document. Attached Figure Description

[0014] Figure 1 An example of raster scan strip segmentation of an image is shown, where the image is divided into 12 slices and 3 raster scan strips.

[0015] Figure 2 An example of rectangular strip segmentation of an image is shown, where the image is divided into 24 slices (6 slice columns and 4 slice rows) and 9 rectangular strips.

[0016] Figure 3 An example of an image divided into slices and rectangular strips is shown, where the image is divided into 4 slices (2 slice columns and 2 slice rows) and 4 rectangular strips.

[0017] Figure 4The image is shown as being divided into 15 slices, 24 strips, and 24 sub-images.

[0018] Figure 5 This is a block diagram of an example video processing system.

[0019] Figure 6 This is a block diagram of a video processing device.

[0020] Figure 7 This is a flowchart of an example method for video processing.

[0021] Figure 8 This is a block diagram illustrating a video encoding / decoding system according to some embodiments of the present disclosure.

[0022] Figure 9 This is a block diagram illustrating an encoder according to some embodiments of the present disclosure.

[0023] Figure 10 This is a block diagram illustrating an encoder according to some embodiments of the present disclosure.

[0024] Figure 11 An example of a typical sub-picture-based viewport-dependent 360° video encoding / decoding scheme is shown.

[0025] Figure 12 A 360° video encoding and decoding scheme based on sub-pictures and spatially scalable viewport-dependent methods is presented.

[0026] Figures 13A to 13D An example flowchart of a video data processing method is shown. Detailed Implementation

[0027] Chapter headings are used in this document for ease of understanding and not to limit the applicability of the techniques and embodiments disclosed in each chapter to that chapter. 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. In this document, current drafts of the VVC specification, editorial changes are indicated in the text by strikethrough indicating undoing and highlighted text indicating addition (including bold and italic).

[0028] 1. Introduction

[0029] This document relates to video codec technology. Specifically, it concerns the specification and signaling of level information for sub-picture sequences. It can be applied to any video codec standard or non-standard video codec that supports single-layer and multi-layer video codecs, such as the Universal Video Codec (VVC) currently under development.

[0030] 2. Abbreviations

[0031] APS Adaptive Parameter Set

[0032] AU Access Unit

[0033] AUD (Access Unit Delimiter)

[0034] AVC (Advanced Video Coding)

[0035] CLVS (Coded Layer Video Sequence)

[0036] CPB Coded Picture Buffer

[0037] CRA Clean Random Access

[0038] CTU (Coding Tree Unit)

[0039] CVS (Coded Video Sequence)

[0040] DCI Decoding Capability Information

[0041] DPB Decoded Picture Buffer

[0042] End of Bitstream (EOB)

[0043] End of Sequence in EOS

[0044] GDR Gradual Decoding Refresh

[0045] HEVC (High Efficiency Video Coding)

[0046] HRD (Hypothetical Reference Decoder)

[0047] Instantaneous Decoding Refresh (IDR)

[0048] Inter-Layer Prediction (ILP)

[0049] ILRP Inter-Layer Reference Picture

[0050] JEM Joint Exploration Model

[0051] LTRP Long-Term Reference Picture

[0052] MCTS Motion-Constrained Tile Sets

[0053] NAL Network Abstraction Layer

[0054] OLS Output Layer Set

[0055] PH Picture Header

[0056] PPS Image Parameter Set

[0057] PTL (Profile, Tier, Level)

[0058] PU Picture Unit

[0059] RAP Random Access Point

[0060] RBSP Raw Byte Sequence Payload

[0061] SEI Supplemental Enhancement Information

[0062] SLI Subpicture Level Information

[0063] SPS Sequence Parameter Set

[0064] STRP Short-Term Reference Picture

[0065] SVC (Scalable Video Coding)

[0066] VCL (Video Coding Layer)

[0067] VPS Video Parameter Set

[0068] VTM VVC Test Model

[0069] VUI Video Usability Information

[0070] VVC (Versatile Video Coding)

[0071] 3. Preliminary Exploration

[0072] Video coding standards have evolved primarily through the development of well-known ITU-T and ISO / IEC standards. ITU-T developed the H.261 and H.263 video standards, ISO / IEC developed the MPEG-1 and MPEG-4 video standards, and the two organizations jointly developed the H.262 / MPEG-2 video standard and the H.264 / MPEG-4 Advanced Video Coding (AVC) and H.265 / HEVC[1]. Since H.262, video coding standards have been based on hybrid video coding architectures, which utilize temporal prediction plus transform coding. In order to explore future video coding 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 a reference software called the Joint Exploration Model (JEM)[2]. JVET meetings are held quarterly in the same location, and the goal of the new coding standard is to reduce the bit rate by 50% compared to HEVC. The new video codec standard was officially named Multifunctional Video Codec (VVC) at the JVET meeting in April 2018, and the first version of the VVC Test Model (VTM) was released at that time. Due to ongoing efforts to standardize VVC, new codec technologies have been adopted into the VVC standard at every JVET meeting. The VVC working draft and test model VTM are updated after each meeting. The VVC project now aims to achieve Technical Finality (FDIS) at the July 2020 meeting.

[0073] 3.1. Image Segmentation Schemes in HEVC

[0074] HEVC includes four different image segmentation schemes: regular striping, dependent striping, slice, and wavefront parallel processing (WPP), which can be used for maximum transmission unit (MTU) size matching, parallel processing, and reduced end-to-end latency.

[0075] Regular slices are similar to slices in H.264 / AVC. Each regular slice is encapsulated in its own NAL unit, and intra-image prediction (inter-frame sample prediction, motion information prediction, and encoding / decoding mode prediction) and entropy encoding / decoding dependencies across slice boundaries are disabled. Therefore, regular slices can be reconstructed independently of other regular slices within the same image (although interdependencies may still exist due to loop filtering operations).

[0076] Regular striping is the only tool available for parallelization, and it is also available in H.264 / AVC in almost the same form. Parallelized regular striping requires minimal inter-processor or inter-core communication (except for inter-processor or inter-core data sharing for motion compensation during image decoding prediction, which is typically much more burdensome than inter-processor or inter-core data sharing due to intra-image prediction). However, for the same reason, the use of regular striping can introduce significant encoding / decoding overhead due to the bit cost of the stripe header and the lack of prediction across stripe boundaries. Furthermore, due to the intra-image independence of regular striping, and the fact that each regular stripe is encapsulated in its own NAL unit, regular striping (as opposed to other tools mentioned below) also serves as a key mechanism for bitstream segmentation to match MTU size requirements. In many cases, the goals of parallelization and MTU size matching impose conflicting requirements on the stripe layout within the image. The implementation of this situation led to the development of the parallelization tools mentioned below.

[0077] Dependency striping features a short stripe header and allows for the segmentation of the bitstream at tree block boundaries without disrupting any in-picture predictions. Essentially, dependency striping provides the option to divide a regular stripe into multiple NAL units to offer reduced end-to-end latency by allowing a portion of the regular stripe to be sent before the entire regular stripe's encoding is complete.

[0078] In WPP, images are segmented into single-row codec tree blocks (CTBs). Entropy decoding and prediction are allowed to use data from CTBs in other segments. Parallel processing is possible through parallel decoding of CTB rows, where the start of CTB row decoding is delayed by two CTBs to ensure that data related to the CTBs above and to the right of the topic CTB is available before decoding the topic CTB. Using this staggered start (which looks like a wavefront when graphically represented), parallelization can be implemented with up to as many processors / cores as the number of CTB rows contained in the image. Because intra-image prediction between adjacent tree block rows within an image is permitted, the inter-processor / inter-core communication required to enable intra-image prediction can be critical. WPP segmentation does not result in the generation of additional NAL units compared to when WPP segmentation is not applied, therefore WPP is not a tool for MTU size matching. However, if MTU size matching is required, regular striping can be used with WPP, but with some encoding / decoding overhead.

[0079] Pieces define the horizontal and vertical boundaries that divide an image into slice columns and slice rows. Slice columns extend from the top to the bottom of the image. Similarly, slice rows extend from the left to the right of the image. The number of slices in an image can be simply derived by multiplying the number of slice columns by the number of slice rows.

[0080] Before decoding the top-left CTB of the next slice in the order of slice raster scans of the image, the CTB scan order is changed to intra-slice local (by slice CTB raster scan order). Similar to regular stripes, slices break intra-image prediction dependencies and entropy decoding dependencies. However, they do not need to be included in separate NAL units (same as WPP in this respect); therefore, slices cannot be used for MTU size matching. Each slice can be processed by one processor / core, and the inter-processor / inter-core communication required for decoding intra-image predictions between processing units of adjacent slices is limited to transmitting a shared stripe header when the slice spans more than one slice, and sharing associated with loop filtering of reconstructed samples and metadata. When more than one slice or WPP segment is included in a stripe, the entry point byte offset of each slice or WTP segment other than the first slice in the stripe is signaled in the stripe header.

[0081] For simplicity, HEVC specifies restrictions on the application of four different image segmentation schemes. For most profiles specified in HEVC, a given codec video sequence cannot simultaneously include slices and wavefronts. For each strip and slice, one or both of the following conditions must be met: 1) All codec tree blocks in a strip belong to the same slice; 2) All codec tree blocks in a slice belong to the same strip. Finally, a wavefront segment contains exactly one CTB line, and when using WPP, if a strip begins within a CTB line, it must end within the same CTB line.

[0082] The recent revisions to HEVC are specified in the JCT-VC output file JCTVC-AC1005, J. Boyce, A. Ramasubramonian, R. Skupin, GJ Sullivan, A. Tourapis, Y.-K. Wang (eds.), “HEVC Additional Supplemental Enhancement Information (Draft 4)”, October 24, 2017, publicly available here: http: / / phenix.int-evry.fr / jct / doc_end_user / documents / 29_Macau / wg11 / JCTVC-AC1005-v2.zip. Including this revision, HEVC specifies three MCTS-related SEI messages: the i-domain MCTS SEI message, the MCTS extracted information set SEI message, and the MCTS extracted data nested SEI message.

[0083] The temporal MCTS SEI message indicates the presence of an MCTS in the bitstream and signals this information to the MCTS. For each MCTS, motion vectors are restricted to pointing to full-sample locations within the MCTS and fractional-sample locations that require interpolation only from full-sample locations within the MCTS. Motion vector candidates derived from blocks outside the MCTS for temporal motion vector prediction are not allowed. This ensures that each MCTS can be decoded independently, without any fragments not included in the MCTS.

[0084] The MCTS Extraction Information Set (SEI) message provides supplementary information that can be used in MCTS sub-bitstream extraction (specified as part of the SEI message semantics) to generate a consistent bitstream for the MCTS set. This information consists of multiple extraction information sets, each defining multiple MCTS sets and containing RBSP bytes for replacing the VPS, SPS, and PPS used in the MCTS sub-bitstream extraction process. When extracting a sub-bitstream according to the MCTS sub-bitstream extraction process, the parameter sets (VPS, SPS, and PPS) need to be rewritten or replaced, and the slice header needs to be slightly updated because one or all slice addresses associated with syntax elements (including first_slice_segment_in_pic_flag and slice_segment_address) typically need to have different values.

[0085] 3.2. Image Segmentation in VVC

[0086] In VVC, an image is divided into one or more slice rows and one or more slice columns. A slice is a sequence of CTUs that covers a rectangular area of ​​the image. The CTUs in a slice are scanned within that slice in raster scan order.

[0087] A strip consists of an integer number of complete slices, or an integer number of consecutive complete CTU rows in a slice of an image.

[0088] Two stripe modes are supported: raster scan stripe mode and rectangular stripe mode. In raster scan stripe mode, a stripe contains a series of complete slices within a sheet raster scan of the image. In rectangular stripe mode, a stripe contains multiple complete slices that together form a rectangular area of ​​the image, or multiple consecutive complete CTU rows of a single slice that together form a rectangular area of ​​the image. Slices within a rectangular stripe are scanned in sheet raster scan order within the rectangular area corresponding to that stripe.

[0089] A sub-image contains one or more stripes that collectively cover a rectangular area of ​​the image.

[0090] Figure 1 An example of raster scan strip segmentation of an image is shown, where the image is divided into 12 slices and 3 raster scan strips.

[0091] Figure 2 An example of rectangular strip segmentation of an image is shown, where the image is divided into 24 slices (6 slice columns and 4 slice rows) and 9 rectangular strips.

[0092] Figure 3 An example is shown where an image is divided into slices and rectangular strips, where the image is divided into 4 slices (2 slice columns and 2 slice rows) and 4 rectangular strips.

[0093] Figure 4 An example of sub-image segmentation of an image is shown, where the image is segmented into 18 slices. Each of the 12 slices on the left side is covered by a 4×4 CTU strip, and each of the 6 slices on the right side is covered by two vertically stacked 2×2 CTU strips, resulting in a total of 24 strips and 24 sub-images of different dimensions (each strip is a sub-image).

[0094] 3.3. Image resolution changes within a sequence

[0095] 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 the image resolution to be changed at some point within the sequence without encoding the IRAP image, which is always intra-frame encoded / decoded. This feature is sometimes called Reference Image Resampling (RPR) because it requires resampling the reference image used for inter-frame prediction when the resolution of the reference image differs from the resolution of the current image being decoded.

[0096] 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 suitable for scaling ratios 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 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 and the left, right, top, and bottom scaling offsets specified for the reference and current images.

[0097] Other aspects of the VVC design that support this feature that differ from HEVC include: i) Picture resolution and the corresponding consistency window are signaled in the PPS instead of the SPS, while the maximum picture resolution is signaled in the SPS. ii) For a single-layer bitstream, each picture storage (the slot in the DPB used to store one decoded picture) occupies the buffer size required to store the decoded picture with the maximum picture resolution.

[0098] 3.4. General Scalable Video Codec (SVC) in VVC

[0099] Scalable video codec (SVC, sometimes also referred to as scalability in video codec) refers to video codec using 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 basic 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 previous coding 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 be used as ELs or RLs, or both. For example, an intermediate layer (e.g., neither the lowest nor the highest layer) can be an EL used for layers below the intermediate layer, such as a base layer or any intermediate enhancement layer, and simultaneously used as an RL for 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).

[0100] In SVC, the parameters used by the encoder or decoder are grouped into parameter sets based on the codec level they can use (e.g., video level, sequence level, picture level, stripe level, etc.). For example, parameters used by one or more codec video sequences from different layers in a bitstream can be included in the Video Parameter Set (VPS), and parameters used by one or more pictures in a codec video sequence can be included in the Sequence Parameter Set (SPS). Similarly, parameters used by one or more stripes in a picture can be included in the Picture Parameter Set (PPS), and additional parameters specific to a single stripe can be included in the stripe header. Likewise, an indication of which parameter set a particular layer uses at a given time can be provided at various codec levels.

[0101] Because VVC supports Reference Picture Resampling (RPR), it's possible to design support for bitstreams containing multiple layers, such as 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, scalability support requires advanced syntax changes (compared to no scalability support). Scalability support was specified in VVC version 1. Unlike scalability support in any earlier video codec standard, including extensions to AVC and HEVC, VVC scalability is designed to be as friendly as possible to single-layer decoder designs. The decoding capability of multi-layer bitstreams is specified in a way that only a single layer exists in the bitstream. For example, decoding capabilities, such as DPB size, are specified independently of the number of layers in the bitstream to be decoded. Essentially, decoders designed for single-layer bitstreams don't require many changes to decode multi-layer bitstreams. Compared to the multi-layer extensions of AVC and HEVC, the HLS aspect is significantly simplified at the expense of some flexibility. For example, IRAP AU requires a picture of every layer present in CVS.

[0102] 3.5. Viewport-dependent 360° video streaming based on sub-images

[0103] In 360° video streaming, also known as panoramic video streaming, at any given moment, only a subset of the entire panoramic video range (i.e., the current viewport) is presented to the user, who can change their viewing direction at any time by turning their head, thus changing the current viewport. While it is desirable to have at least some lower-quality representation in areas not covered by the currently available viewport, and to be prepared for the user to suddenly change their viewing angle to any location within the range, a high-quality representation of the panoramic video is only needed for the current viewport being presented to the user. This optimization is achieved by dividing the high-quality representation of the entire panoramic video into sub-pictures with appropriate granularity. Using VVC, these two representations can be encoded as two independent layers.

[0104] A typical sub-image-based viewport-dependent 360° video transmission scheme is shown below. Figure 11 In this context, a higher-resolution representation of the complete video consists of sub-pictures, while a lower-resolution representation of the complete video does not use sub-pictures and can be encoded and decoded using less frequent random access points than the higher-resolution representation. The client receives the complete video at the lower resolution, and for the higher-resolution video, it only receives and decodes the sub-pictures covering the current viewport.

[0105] The latest VVC draft specification also supports improved 360° video codec schemes, such as... Figure 12 As shown. With Figure 11The only difference between the methods shown is that intra-frame prediction (ILP) is applied. Figure 12 The method shown in the figure.

[0106] 3.6. Parameter Set

[0107] AVC, HEVC, and VVC specify parameter sets. Parameter set types include SPS, PPS, APS, and VPS. All AVC, HEVC, and VVC implementations support SPS and PPS. VPS was introduced with HEVC and is included in both HEVC and VVC. APS is not included in AVC or HEVC but is included in the latest VVC draft text.

[0108] SPS is designed to carry sequence-level header information, and PPS is designed to carry infrequently changing image-level header information. With SPS and PPS, it is unnecessary to repeat infrequently changing information for each sequence or image, thus avoiding redundant signaling. Furthermore, using SPS and PPS enables out-of-band transmission of important header information, thereby not only avoiding the need for redundant transmission but also improving fault tolerance.

[0109] The VPS was introduced to carry sequence-level header information that is common to all layers in a multi-layer bitstream.

[0110] The purpose of APS is to carry image-level or strip-level information, which requires a considerable number of bits to encode and decode. This information can be shared by multiple images and can have many different variations within a sequence.

[0111] 3.7. Sub-image Sub-bitstream Extraction Process

[0112] The proposed changes to the sub-image sub-bitstream extraction process in the latest VVC text clause C.7, plus ByteDance ID FP2005612001H_v0, are as follows.

[0113] C.7 Sub-image Sub-bitstream Extraction Process

[0114] The input to this process is a bitstream inBitstream, a target OLS index targetOlsIdx, a target highest TemporalId value tIdTarget, and a list of target subpic index values ​​subpicIdxTarget[i] from 0 to NumLayersInOls[targetOLsIdx] - 1 (inclusive of 0 and NumLayersInOls[targetOLsIdx] - 1).

[0115] The output of this process is the sub-bitstream outBitstream.

[0116] The bitstream consistency requirement for the input bitstream is that any output sub-bitstream that satisfies all of the following conditions should be a consistent bitstream:

[0117] – The output sub-bitstream is the output of the procedure with bitstream specified in this clause, where targetOlsIdx is equal to the index of the OLS list specified by the VPS, tIdTarget is equal to any value in the range 0 to vps_max_sublayers_minus1 (inclusive), and a list subpicIdxTarget[i] from 0 to NumLayersInOls[targetOLsIdx] - 1 (inclusive) satisfies the following conditions as input:

[0118] – All layers in the targetOLsIdx OLS have the same spatial resolution, the same sps_num_subpics_minus1 value, and the same subpic layout, and all subpics have sps_subpic_treated_as_pic_flag[] equal to 1.

[0119] The value of –subpicIdxTarget[i] is the same for all i values ​​and is equal to a specific value in the range of 0 to sps_num_subpics_minus1 (inclusive).

[0120] – When NumLayersInOls[targetOlsIdx] is greater than 1 and sps_num_subpics_minus1 is greater than 0, the subpicture level information SEI message should exist in a scalable nesting SEI message in which sn_ols_flag is equal to 1 and for an i value in the range of 0 to sn_num_olss_minus1 (inclusive), NestingOlsIdx[i] is equal to targetOlsIdx.

[0121] For use with multi-tiered OLS, the SLI SEI message should be included in a scalable nested SEI message, and the scalable nested SEI message should indicate whether it is applicable to a specific OLS or applicable to all layers in a specific OLS.

[0122] – The output sub-bitstream contains at least one VCL NAL unit whose nuh_layer_id is equal to each nuh_layer_id value in the list LayerIdInOls[targetOlsIdx].

[0123] – The output sub-bitstream contains at least one VCL NAL unit whose TemporalId is equal to tIdTarget.

[0124] Note – A consistent bitstream contains one or more codec stripe NAL units with TemporalId equal to 0, but does not necessarily contain codec stripe NAL units with nuh_layer_id equal to 0.

[0125] – The output sub-bitstream contains at least one VCL NAL unit where nuh_layer_id is equal to LayerIdInOls[targetOlsIdx][i] and sh_subpic_id is equal to SubpicIdVal[subpicIdxTarget[i]], where each i is in the range from 0 to NumLayersInOls[targetOlsIdx]-1 (inclusive of 0 and NumLayersInOls[targetOlsIdx]-1).

[0126] The derivation of the output sub-bitstream, outBitstream, is as follows:

[0127] – The sub-bitstream extraction procedure specified in Appendix C.6 is called with inBitstream, targetOlsIdx, and tIdTarget as inputs, and the output of the procedure is assigned to outBitstream.

[0128] For each i value in the range from 0 to NumLayersInOls[targetOLsIdx] - 1 (inclusive), remove from outBitstream all VCL NAL units whose nuh_layer_id is equal to LayerIdInOls[targetOLsIdx][i] and sh_subpic_id is not equal to SubpicIdVal[subpicIdxTarget[i]], their associated padding data NAL units, and the SEINAL unit containing the padding payload SEI message.

[0129] – When sli_cbr_constraint_flag equals 0, remove all NAL units with nal_unit_type equal to FD_NUT and SEI NAL units containing SEI messages that fill the payload.

[0130] –If certain external means not specified in this specification are available to provide a replacement parameter set for the sub-bitstream outBitstream, then replace all parameter sets with the replacement parameter set.

[0131] – Otherwise, when the sub-image level information SEI message exists in inBitstream, the following applies:

[0132] – Rewrite the value of general_level_idc in the vps_ols_ptl_idx[targetOlsIdx]th entry of the profile_tier_level() syntax structure list in all referenced VPS NAL units, making it equal to SubpicSetLevelIdc, which is derived from equation D.11 for the subpick set consisting of subpicks whose subpick index is equal to subpicIdx.

[0133] – When VCL HRD parameters or NAL HRDs exist, rewrite the corresponding values ​​of cpb_size_value_minus1[tIdTarget][j] and bit_rate_value_minus1[tIdTarget][j] in the ols_hrd_idx[MultiLayerOlsIdx[targetOlsIdx]] syntax structure of the j-th CPB in all referenced VPS NAL units, as well as in the ols_hrd_parameters() syntax structure of all SPS NAL units referenced at the i-th layer, such that they correspond to the values ​​of SubpicCpbSizeVcl[SubpicSetLevelIdx][subpicIdx] and SubpicCpbSizeNal[SubpicSetLevelIdx][subpicIdx] derived from Equations D.6 and D.7, respectively. , and respectively corresponding to SubpicBitrateVcl[SubpicSetLevelIdx] and SubpicBitrateNal[SubpicSetLevelIdx][subpicIdx] derived from equations D.8 and D.9, where SubpicSetLevelIdx is derived from equation D.11 for the subpick index equal to subpicIdx, j is in the range from 0 to hrd_cpb_cnt_minus1 (inclusive of 0 and hrd_cpb_cnt_minus1), and i is in the range from 0 to NumLayersInOls[targetOlsIdx]-1 (inclusive of 0 and NumLayersInOls[targetOlsIdx]-1).

[0134] – For each i value in the range from 0 to NumLayersInOls[targetOlsIdx] - 1, the following applies.

[0135] – The variable spIdx is set to be equal to subpicIdxTarget[i].

[0136] – Rewrite the value of general_level_idc in the profile_tier_level() syntax structure of all referenced SPS NAL units where sps_ptl_dpb_hrd_params_present_flag is equal to 1. This value is equal to SubpicSetLevelIdc, which is derived from Equation D.11 for the set of subpicks consisting of subpicks whose subpick index is equal to spIdx.

[0137] The derivation of variables subpicWidthInLumaSamples and subpicHeightInLumaSamples is as follows:

[0138]

[0139] – Rewrite the values ​​of sps_pic_width_max_in_luma_samples and sps_pic_height_max_in_luma_samples in all referenced SPS NAL cells, and the values ​​of pps_pic_width_in_luma_samples and pps_pic_height_in_luma_samples in all referenced PPS NAL cells, so that they are equal to subpicWidthInLumaSamples and subpicHeightInLumaSamples, respectively.

[0140] – Rewrite the value of sps_num_subpics_minus1 in all referenced SPS NAL cells and pps_num_subpics_minus1 in all referenced PPS NAL cells to 0.

[0141] – Rewrite the syntax elements sps_subpic_ctu_top_left_x[spIdx] and sps_subpic_ctu_top_left_y[spIdx] (if they exist) in all referenced SPS NAL units to 0.

[0142] – Remove the syntax elements sps_subpic_ctu_top_left_x[j], sps_subpic_ctu_top_left_y[j], sps_subpic_width_minus1[j], sps_subpic_height_minus1[j], sps_subpic_treated_as_pic_flag[j], sps_loop_filter_across_subpic_enabled_flag[j], and sps_subpic_id[j] from all referenced SPS NAL units, where j is not equal to spIdx.

[0143] – Rewrite all syntax elements in the reference PPS to signal slices and stripes to remove all slice rows, slice columns, and stripes that are not related to the sub-image with a sub-image index equal to spIdx.

[0144] The derivation of the variables subpicConfWinLeftOffset, subpicConfWinRightOffset, subpicConfWinTopOffset, and subpicConfWinBottomOffset is as follows:

[0145]

[0146] In the above equation, sps_subpic_ctu_top_left_x[spIdx], sps_subpic_width_minus1[spIdx], sps_subpic_ctu_top_left_y[spIdx], sps_subpic_height_minus1[spIdx], sps_pic_width_max_in_luma_samples, sps_pic_height_max_in_luma_samples, sps_conf_win_left_offset, sps_conf_win_right_offset, sps_conf_win_top_offset, and sps_conf_win_bottom_offset come from the original SPS before its rewrite.

[0147] – Rewrite the values ​​of sps_conf_win_left_offset, sps_conf_win_right_offset, sps_conf_win_top_offset, and sps_conf_win_bottom_offset in all referenced SPS NAL units, and the values ​​of pps_conf_win_left_offset, pps_conf_win_right_offset, pps_conf_win_top_offset, and pps_conf_win_bottom_offset in all referenced PPS NAL units, so that they are equal to subpicConfWinLeftOffset, subpicConfWinRightOffset, subpicConfWinTopOffset, and subpicConfWinBottomOffset, respectively.

[0148] The derivation of the variables subpicScalWinLeftOffset, subpicScalWinRightOffset, subpicScalWinTopOffset, and subpicScalWinBotOffset is as follows:

[0149]

[0150] In the above equation, sps_subpic_ctu_top_left_x[spIdx], sps_subpic_width_minus1[spIdx], sps_subpic_ctu_top_left_y[spIdx], sps_subpic_height_minus1[spIdx], sps_pic_width_max_in_luma_samples, and sps_pic_height_max_in_luma_samples come from the original SPS before its rewrite, and pps_scaling_win_left_offset, pps_scaling_win_right_offset, pps_scaling_win_top_offset, and pps_scaling_win_bottom_offset come from the original PPS before its rewrite.

[0151] – Rewrite the values ​​of pps_scaling_win_left_offset, pps_scaling_win_right_offset, pps_scaling_win_top_offset, and pps_scaling_win_bottom_offset in all reference PPS NAL units to be equal to subpicScalWinLeftOffset, subpicScalWinRightOffset, subpicScalWinTopOffset, and subpicScalWinBotOffset, respectively.

[0152] – If sli_cbr_constraint_flag equals 1, then set cbr_flag[tIdTarget][j] to 1, which is the value of the j-th CPB in the vps_ols_hrd_idx[MultiLayerOlsIdx[targetOlsIdx]]-th ols_hrd_parameters() syntax structure in all referenced VPS NAL units and SPS NAL units, and j is in the range from 0 to hrd_cpb_cnt_minus1. Otherwise (sli_cbr_constraint_flag equals 0), set cbr_flag[tIdTarget][j] to 0.

[0153] – When outBitstream contains an SEI NAL unit (where the SEI NAL unit contains a scalable nested SEI message applicable to outBitstream with sn_ols_flag equal to 1 and sn_subpic_flag equal to 1), extract the appropriate non-scalable-nested SEI message with payloadType equal to 1 (PT), 130 (DUI), or 132 (decoded image hash) from the scalable nested message, and put the extracted SEI message into outBitstream.

[0154] 4. The technical problem solved by the disclosed technical solution

[0155] The latest design of the sub-image sub-bitstream extraction process has the following problems:

[0156] 1)1) SEI NAL units include scalable-nested SEI messages in scalable-nested SEI messages with sn_subpic_flag equal to 1. These messages are not applicable to the output bitstream and should be removed from the output bitstream.

[0157] 2) The sub-image index used to identify the sub-image sequence should be the sub-image index of the layer where each image has multiple sub-images, rather than the sub-image index of the sub-image to be extracted in the layer where each image has only one sub-image.

[0158] 3) The rewriting of sublayer_level_idc[k] in the range of 0 to tIdTarget - 1 (inclusive) is missing, and it is not explicitly specified under what conditions the execution level information of the reference VPS and / or reference SPS should be rewritten.

[0159] 4) The rewriting of cpb_size_value_minus1[k][j] and bit_rate_value_minus1[k][j] in the range of k from 0 to tIdTarget - 1 (inclusive) is missing, and it is not explicitly specified under what conditions the CPB size and bit rate information should be rewritten for the reference VPS and / or reference SPS.

[0160] 5) It is not clearly specified under what conditions cbr_flag[tIdTarget][j] should be overridden for reference VPS and / or reference SPS.

[0161] 6) There are several problems with the final step of making a scalable nested SEI message a non-scalable nested SEI message:

[0162] a. When the decoded image hash SEI message is contained within a scalable nested SEI message, the value of sn_ols_flag needs to be equal to 0, while the current text in the last step assumes that sn_ols_flag is equal to 1.

[0163] b. SLI messages and BP SEI messages are not overwritten when sn_ols_flag equals 1 and sn_subpic_flag equals 1.

[0164] c. SEI messages are not overwritten when sn_ols_flag equals 0 and sn_subpic_flag equals 1.

[0165] d. The location in the output bitstream where the resulting non-scalable nested SEI messages should be placed is not specified (in which SEI NAL, where the SEI NAL unit should be located).

[0166] e. The original container SEI NAL unit should be removed from the output bitstream.

[0167] 5. List of Solutions and Implementation Examples

[0168] To address the aforementioned and other issues, methods outlined below are disclosed. These solution items should be considered as examples to illustrate general concepts, and not interpreted narrowly. Furthermore, these items can be applied individually or in combination in any way.

[0169] 1) To solve problem 1, during the sub-image sub-bitstream extraction process, it can be specified that SEI NAL units containing scalable nested SEI messages that are not applicable to the output bitstream are removed from the output bitstream.

[0170] 2) To solve problem 2, the following can be specified during the sub-image sub-bitstream extraction process: the sub-image index used to identify the sub-image sequence is specified as the sub-image index of the sub-image to be extracted in the layer where each image has multiple sub-images, rather than the layer where each image has only one sub-image.

[0171] 3) To address problem 3, during the sub-image sub-bitstream extraction process, the following can be specified: For k in the range of 0 to tIdTarget - 1 (inclusive), both general_level_idc and sublayer_level_idc[k] in the reference VPS (if present) and the reference SPS (when NumLayersInOls[targetOLsIdx] equals 0) are rewritten to appropriate values ​​(e.g., as described in this paper).

[0172] 4) To address problem 4, during the sub-image sub-bitstream extraction process, the following can be specified: For all k values ​​in the range of 0 to tIdTarget (inclusive), rewrite cpb_size_value_minus1[k][j] and bit_rate_value_minus1[k][j] in the reference VPS (if present) and the reference SPS (when NumLayersInOls[targetOLsIdx] equals 0) to appropriate values ​​(e.g., as described in this paper).

[0173] 5) To solve problem 5, during the extraction of sub-image sub-bitstreams, the following can be specified: rewrite cbr_flag[tIdTarget][j] in the referenced VPS (if it exists) and the referenced SPS (when NumLayersInOls[targetOLsIdx] equals 0) to an appropriate value (e.g., as described in this article).

[0174] 6) To solve problem 6, under certain conditions, one or more of the following operations can be performed:

[0175] a. Generate a new SEI NAL unit seiNalUnitB.

[0176] b. Include seiNalUnitB in the PU that contains seiNalUnitA.

[0177] c. In a PU that contains seiNalUnitA, seiNalUnitB is included immediately following seiNalUnitA.

[0178] d. Extract the scalable nested SEI message from the scalable nested SEI message and include it directly in seiNalUnitB (as a non-scalable nested SEI message).

[0179] e. Remove seiNalUnitA from outBitstream.

[0180] 7) In one example, a certain condition in item 6) is as follows: when outBitstream contains a SEI NAL unit seiNalUnitA, where the SEI NAL unit contains a scalable nested SEI message with sn_subpic_flag equal to 1, the scalable nested SEI message applies to OLS (when sn_ols_flag equals 1) or layers whose layer set is exactly the same as the layer set in outBitstream (when sn_ols_flag equals 0) and applies to subpicks whose subpicks are the same as the subpicks in outBitstream.

[0181] 8) In one example, during the extraction of a sub-image sub-bitstream, when LayerIdInOls[targetOlsIdx] does not include all values ​​of nuh_layer_id in all NAL units in the bitstream, and outBitstream contains SEI NAL units seiNalUnitA containing scalable nested SEI messages, keep seiNal UnitA unchanged in the output bitstream.

[0182] 6. Examples

[0183] The following are some example embodiments of some aspects of the invention outlined in Section 5 above, which are applicable to the VVC specification. The modified text is based on the latest VVC text in JVET-S0152-v5. Most of the relevant added or modified sections are... Highlighted, some deleted sections are... Highlighted. There may be other editable changes, which are not highlighted.

[0184] 6.1. First Embodiment

[0185] This embodiment applies to items 1 through 7 and their sub-items.

[0186] C.7 Sub-image Sub-bitstream Extraction Process

[0187] The inputs to this process are the bitstream inBitstream, the target OLS index targetOlsIdx, the highest target TemporalId value tIdTarget, and... Target sub-image index value subpicIdxTarget .

[0188] The output of this process is the sub-bitstream outBitstream.

[0189]

[0190] The bitstream consistency requirement for the input bitstream is that any output sub-bitstream that satisfies all of the following conditions should be a consistent bitstream:

[0191] – The output sub-bitstream is the output of the procedure with bitstream specified in this clause, where targetOlsIdx is equal to the index of the OLS list specified by the VPS.

[0192] – The output sub-bitstream contains at least one VCL NAL unit whose nuh_layer_id is equal to Each value in the nuh_layer_id value in LayerIdInOls[targetOlsIdx].

[0193] – The output sub-bitstream contains at least one VCL NAL unit whose TemporalId is equal to tIdTarget.

[0194] Notice - A consistent bitstream contains one or more codec stripe NAL units with TemporalId equal to 0, but does not necessarily contain codec stripe NAL units with nuh_layer_id equal to 0.

[0195] For each value of i in the range of 0 to NumLayersInOls[targetOlsIdx]-1 (inclusive), the output sub-bitstream contains nuh_layer_id equal to LayerIdInOls[targetOlsIdx][i] and sh_subpic_id equal to SubpicIdVal[subpicIdxTarget[i]]. At least one VCL NAL unit.

[0196] output sub-bitstream Derivation:

[0197] 1. The sub-bitstream extraction procedure specified in Appendix C.6 is called with inBitstream, targetOlsIdx, and tIdTarget as inputs, and the output of the procedure is assigned to outBitstream.

[0198]

[0199] 5. If certain external means not specified in this specification are available to provide a replacement parameter set for the sub-bitstream outBitstream, then all parameter sets shall be replaced with the replacement parameter set. Otherwise, when the SLI SEI message is present in inBitstream, the following...

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[0201]

[0202]

[0203]

[0204]

[0205]

[0206]

[0207] Figure 5 This is a block diagram illustrating an example video processing system 1900 to 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 and Passive Optical Network (PON), and wireless interfaces such as Wi-Fi or cellular interfaces.

[0208] System 1900 may include a codec component 1904 capable of implementing the various codec or encoding methods described herein. 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. The stored or transmitted bitstream (or codec) representation of the video received at input 1902 can be used by component 1908 to generate pixel values ​​or displayable video that is sent to display interface 1810. The process of generating a user-viewable video from the bitstream representation is sometimes referred to as video decompression. Furthermore, although some video processing operations are referred to as "codec" operations or tools, it should be understood that encoding tools or operations are used at the encoder, and corresponding decoding tools or operations will be performed by the decoder to reverse the encoded results.

[0209] 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, and so on. The technologies described herein can be found 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.

[0210] Figure 6 This 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. The processors (multiple processors) 3602 can be configured to implement one or more methods described herein. The memories (multiple memories) 3604 can be used to store data and code for implementing the methods and techniques described herein. The video processing hardware 3606 can be used to implement some of the techniques described in this document in hardware circuitry.

[0211] Figure 8 This is a block diagram illustrating an example video codec system 100 that can utilize the techniques disclosed herein.

[0212] like Figure 8 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 and may be referred to as a video encoding device. The destination device 120 can decode the encoded video data generated by the source device 110, and the source device may be referred to as a video decoding device.

[0213] The source device 110 may include a video source 112, a video encoder 114, and an input / output (I / O) interface 116.

[0214] 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 images. Video encoder 114 encodes the video data from video source 112 to generate a bitstream. The bitstream may include a sequence of bits forming a codec representation of the video data. The bitstream may include codec images and associated data. A codec image is a codec representation of an image. Associated data may include sequence parameter sets, image 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.

[0215] The target device 120 may include an I / O interface 126, a video decoder 124, and a display device 122.

[0216] 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.

[0217] 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 (VVM) standard, and other current and / or further standards.

[0218] Figure 9 This is a block diagram illustrating an example of a video encoder 200. The video encoder can be... Figure 8 The video encoder 114 in the system 100 shown.

[0219] The video encoder 200 can be configured to perform any or all of the technologies disclosed herein. Figure 9 In the example, the video encoder 200 includes multiple functional components. The techniques described in this disclosure 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.

[0220] 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.

[0221] 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.

[0222] Furthermore, some components (e.g., motion estimation unit 204 and motion compensation unit 205) can be highly integrated, but for interpretative purposes... Figure 9 The example is shown separately.

[0223] 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.

[0224] The mode selection unit 203 may, for example, select one of multiple encoding / decoding modes (intra-frame or inter-frame) based on the error result, and provide the resulting intra-frame or inter-frame encoded / decoded block to the residual generation unit 207 to generate residual block data, and to the reconstruction unit 212 to reconstruct the encoded block for use as a reference picture. In some examples, the mode selection unit 203 may select a combination of intra-frame and inter-frame prediction (CIIP) modes, where prediction is based on inter-frame prediction signaling and intra-frame prediction signaling. In the case of inter-frame prediction, the mode selection unit 203 may also select the resolution of the motion vector for the block (e.g., sub-pixel or integer pixel precision).

[0225] 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 and decoded samples from images other than those associated with the current video block from buffer 213.

[0226] 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.

[0227] 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 the reference images of list 0 or list 1. Motion estimation unit 204 can then generate a reference index indicating the reference images in list 0 or list 1, which includes 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.

[0228] 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, where the reference index indicates the reference images in lists 0 and 1 containing 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 blocks indicated by the motion information of the current video block.

[0229] In some examples, the motion estimation unit 204 can output a complete set of motion information for the decoder's decoding processing.

[0230] In some examples, the motion estimation unit 204 may not output the complete set of motion information for the current video. Instead, the motion estimation unit 204 may signal the motion information of the current video block to another video block. For example, the 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.

[0231] 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.

[0232] In another example, motion estimation unit 204 can identify another video block and motion vector difference (MVD) within the syntactic 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.

[0233] As discussed 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 merge mode signaling.

[0234] 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 decoded samples from 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.

[0235] The residual generation unit 207 can generate residual data for the current video block by subtracting (e.g., indicated by a negative sign) the predicted video block of the current video block 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.

[0236] 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.

[0237] The transform processing 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.

[0238] After the transform processing 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.

[0239] 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 of one or more predicted video blocks generated by prediction unit 202 to generate a reconstructed video block associated with the current block, which is stored in buffer 213.

[0240] After the video block is reconstructed by reconstruction unit 212, a loop filtering operation can be performed to reduce video block artifacts in the video block.

[0241] 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 bit stream including the entropy encoded data.

[0242] Figure 10 This is a block diagram illustrating an example of a video decoder 300, which can be... Figure 8 The video decoder 114 in the system 100 shown.

[0243] The video encoder 300 can be configured to perform any or all of the technologies disclosed herein. Figure 10 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.

[0244] exist Figure 10 In the example, 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, video decoder 300 can perform functions typically associated with video encoder 200. Figure 9 The decoding process is the inverse of the encoding process described.

[0245] Entropy decoding unit 301 can retrieve encoded bitstreams. The encoded bitstreams may include entropy-encoded / decoded video data (e.g., encoded blocks of video data). Entropy decoding unit 301 can decode the entropy-encoded / decoded video data, and from the entropy-decoded video data, motion compensation unit 302 can determine motion information, including motion vectors, motion vector precision, reference image list index, and other motion information. Motion compensation unit 302 can determine this information, for example, by performing AMVP and merge modes.

[0246] The motion compensation unit 302 can generate motion compensation blocks and can perform interpolation based on an interpolation filter. The identifier of the interpolation filter to be used at sub-pixel precision can be included in the syntax element.

[0247] The motion compensation unit 302 can use interpolation filters, such as those used by the video encoder 200 during the encoding of video blocks, to calculate interpolated 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 the prediction block.

[0248] The motion compensation unit 302 may use some syntax information to determine the size of the blocks of frames and / or stripes used to encode the encoded video sequence, 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) for each inter-frame coded block, and other information for decoding the encoded video sequence.

[0249] 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 303 inverse quantizes (i.e., dequantizes) the quantized video block coefficients provided in the bitstream and decoded by entropy decoding unit 301. Inverse transform unit 303 applies an inverse transform.

[0250] The reconstruction unit 306 can add the residual block to the corresponding prediction block generated by the motion compensation unit 202 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 decoded video for presentation on a display device.

[0251] The following is a list of preferred solutions for some embodiments.

[0252] The following solutions show example embodiments of the techniques discussed in the previous section (e.g., items 1 through 8).

[0253] 1. A video processing method (e.g., Figure 7 The method 700 shown includes: performing (702) a conversion between a video comprising one or more sub-images and a codec representation of the video, wherein the codec representations are organized in one or more Network Abstraction Layer (NAL) units, wherein the conversion is performed according to rules that specify the configuration or extraction of sub-bitstreams of sub-images through a sub-image sub-bitstream extraction process.

[0254] The following solutions show example embodiments of the techniques discussed in the previous section (e.g., item 1).

[0255] 2. The method according to Solution 1, wherein the rule specifies the removal of Supplemental Enhancement Information (SEI) NAL units, including scalable nested SEI messages that are not applicable to the output bitstream, from the output bitstream.

[0256] The following solutions show example embodiments of the techniques discussed in the previous section (e.g., item 2).

[0257] 3. The method according to any one of solutions 1 to 2, wherein the rule specifies that the sub-image index used to identify the sub-image sequence corresponds to the sub-image index of the sub-image to be extracted in the video layer where each image includes multiple sub-images.

[0258] The following solutions show example embodiments of the techniques discussed in the previous section (e.g., item 3).

[0259] 4. The method according to any one of solutions 1 to 3, wherein the rule specifies that, when the number of layers in the output layer set is 1, the first syntax element indicating the general level and the second syntax element indicating the layer level are rewritten to another value.

[0260] The following solutions show example embodiments of the techniques discussed in the previous section (e.g., item 4).

[0261] 5. The method according to any one of solutions 1 to 4, wherein the rule specifies that, when the number of layers in the output layer set is 1, the first syntax element indicating the size of the codec image buffer and the second syntax element indicating the bit rate are rewritten to another value (e.g., an appropriate value as described herein).

[0262] The following solutions show example embodiments of the techniques discussed in the previous section (e.g., items 5 through 8).

[0263] 6. The method according to any one of solutions 1 to 5, wherein the rule specifies that the value of the syntax field indicating the codec bit rate in the reference video parameter set or sequence parameter set is rewritten to another value (e.g., an appropriate value as described herein).

[0264] 7. The method according to any one of solutions 1 to 6, wherein the conversion includes encoding the video into the codec representation.

[0265] 8. The method according to any one of solutions 1 to 6, wherein the conversion includes decoding the codec representation to generate pixel values ​​of the video.

[0266] 9. A video decoding apparatus, comprising a processor configured to implement one or more of the methods described in solutions 1 to 8.

[0267] 10. A video encoding apparatus, comprising a processor configured to implement one or more of the methods described in solutions 1 to 8.

[0268] 11. 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 8.

[0269] 12. A method, apparatus or system described in this document.

[0270] In the solution described in this paper, the encoder conforms to the format rules by generating a codec representation based on those rules. In the solution described in this paper, the decoder can use the format rules to parse the syntax elements in the codec representation, knowing whether or not they exist, to generate the decoded video.

[0271] In this paper, the term "video processing" can refer to video encoding, video decoding, video compression, or video decompression. For example, a video compression algorithm can be applied during the conversion from a pixel representation of a video to a corresponding bitstream representation, and vice versa. As defined by the syntax, the bitstream representation of the current video block can, for example, correspond to bits juxtaposed or scattered at different positions within the bitstream. For example, macroblocks can be encoded based on the transform and encoding / decoding error residuals, and can also utilize bits in the header and other fields in the bitstream. Furthermore, during the conversion, the decoder can parse the bitstream based on determining whether some fields may be present or absent, as described in the solutions above. Similarly, the encoder can determine whether to include or exclude certain syntax fields and generate the codec representation accordingly by including or excluding syntax fields from the codec representation.

[0272] In some preferred embodiments, the first set of solutions may be implemented as further described in items 1 and 2 of Section 5.

[0273] 1. A method for processing video data (e.g., Figure 13A The method shown (1300) includes: performing (1302) a conversion between a video and a bitstream of the video, wherein, according to a rule, the bitstream includes multiple layers, each layer including one or more sub-pictures; wherein, the rule specifies that, during the sub-picture sub-bitstream extraction process of extracting the output bitstream from the bitstream, a Supplemental Enhanced Information Network Abstraction Layer (SEI NAL) unit, which includes scalable nested SEI messages that are not applicable to the output bitstream, is omitted from the output bitstream.

[0274] 2. The method according to Solution 1, wherein the output bitstream includes one or more output layers, the output layers including sub-pictures identified by one or more target sub-picture indices, and wherein, in response to the scalable nested SEI including a flag with a predetermined value and one or more first sub-picture indices of the SEI-NAL unit not matching one or more second sub-picture indices in the output bitstream, the SEI NAL unit is considered unsuitable for the output bitstream.

[0275] 3. The method according to Solution 2, wherein a flag with a predetermined value indicates that the SEI NAL unit is applicable to a specific sub-picture of a specific layer.

[0276] 4. The method according to solutions 2 to 3, wherein the flag is sn_subpic_flag.

[0277] 5. The method according to any one of solutions 2 to 4, wherein the one or more first subpick indices are sn_subpic_idx[j], where j is an integer and the value of j ranges from 0 to sn_num_subpics_minus1, and wherein the one or more second subpick indices are subpicIdxTarget[i], which is used for layers in the output bitstream where each picture has multiple subpicks, where i is an integer.

[0278] 6. A method for processing video data (e.g., Figure 13B The method shown (1310) includes: performing a conversion between a video and a bitstream of the video, wherein, according to a rule, the bitstream includes multiple layers, each layer including one or more pictures, and each picture including one or more sub-pictures; wherein, the rule specifies that a first sub-picture index identifying a sequence of sub-pictures extracted by a sub-picture sub-bitstream extraction process on the bitstream is a second sub-picture index based on a layer of the bitstream where each picture has multiple sub-pictures.

[0279] 7. The method according to Solution 6, wherein the rule specifies that the first sub-picture index responds to a Sub-Picture Level Information Supplemental Enhancement Information (SLI SEI) message included in the bitstream.

[0280] In some preferred embodiments, the second set of solutions may be implemented as further described in items 3, 4 and 5 of Section 5.

[0281] 1. A method for processing video data (e.g., Figure 13C The method shown (1320) includes: performing (1322) a conversion between a video and a bitstream of the video, wherein, according to a rule, the bitstream includes one or more layers, the layers include one or more sub-layers, the sub-layers include one or more pictures, the pictures include one or more sub-pictures, wherein the rule specifies a rewrite operation selectively performed on one or more syntax structures during the extraction process of sub-picture sub-bitstreams from the bitstream to extract the output target sub-bitstream, wherein the one or more syntax elements include information about the output target sub-bitstream.

[0282] 2. The method according to Solution 1, wherein the one or more syntax elements include a first syntax structure and a second syntax structure, the first syntax structure indicating the encoding / decoding level conformed to by the output target sub-bitstream, and the second syntax structure indicating the encoding / decoding level conformed to by the sub-layer sequence in the output target sub-bitstream with index values ​​from 0 to tIdTarget-1, wherein tIdTarget is an integer representing the highest temporal layer identifier of the sub-layer in the output target sub-bitstream.

[0283] 3. The method according to Solution 1, wherein the one or more syntax elements include a first syntax structure and a second syntax structure, the first syntax structure indicating the codec image buffer size of each sub-layer sequence in the output target sub-bitstream, and the second syntax structure indicating the bitrate value of each sub-layer sequence in the output target sub-bitstream.

[0284] 4. The method according to Solution 1, wherein the one or more syntax elements include: (a) a first syntax structure indicating whether each sub-layer sequence in the output target sub-bitstream is processed to have a constant bit rate.

[0285] 5. The method according to solutions 1 to 2, wherein the first syntax structure and the second syntax structure are included in a set of video parameters referenced by the output target sub-bitstream.

[0286] 6. The method according to solutions 1 to 2, wherein, in the case that the output target sub-bitstream comprises a single layer, the sequence parameter set referenced by the output target sub-bitstream includes the first syntax structure and the second syntax structure.

[0287] In some preferred embodiments, the third set of solutions may be implemented as further described in items 6, 7 and 8 of Section 5.

[0288] 1. A method for processing video data (e.g., Figure 13D The method shown (1330) includes: performing (1332) a conversion between a video and a bitstream of the video, wherein, according to a rule, the bitstream includes one or more layers, the layers include one or more pictures, the pictures include one or more sub-pictures, wherein the rule specifies selective processing of a first Supplemental Enhanced Information Network Abstraction Layer (SEI NAL) unit of a target output sub-picture sub-bitstream extracted during the sub-picture sub-bitstream extraction process in response to a condition.

[0289] 2. The method according to Solution 1, wherein the process includes generating the first SEI NAL unit.

[0290] 3. The method according to any one of solutions 1 to 2, wherein the processing includes adding the first SEINAL unit to an image unit including the second SEINAL unit.

[0291] 4. The method according to any one of solutions 1 to 3, wherein the processing includes adding the first SEINAL unit to the image unit, the image unit including a second SEINAL unit immediately following the second SEINAL unit.

[0292] 5. The method according to any one of solutions 1 to 4, wherein the processing includes extracting a scalable nested SEI message from the scalable nested SEI message in the second SEINAL unit, and including the extracted scalable nested SEI message as a non-scalable nested SEI message in the first SEINAL unit.

[0293] 6. The method according to any one of solutions 1 to 5, wherein the processing includes removing a second SEI NAL unit from the target output sub-image sub-bitstream.

[0294] 7. The method according to solutions 1 to 6, wherein the conditions include: (a) the target output sub-picture sub-bitstream includes the second SEI NAL unit, the second SEI NAL unit including a scalable nested SEI message; (b) the syntax field in the scalable nested SEI message is set to a value indicating that the scalable nested SEI message is applicable to the same layer set as the layer set in the target output sub-picture sub-bitstream; and (c) the scalable nested SEI message is applicable to the same sub-picture set as the sub-picture set in the target output sub-picture sub-bitstream.

[0295] 8. The method according to Solution 1, wherein the conditions include: (a) the list of layers in the target output sub-image sub-bitstream does not include all layers in the bitstream; (b) the target output sub-image sub-bitstream includes scalable nested SEI messages; and wherein the processing includes keeping the first SEI NAL unit in the target output sub-image sub-bitstream unchanged.

[0296] 9. The method according to any one of solutions 1 to 8, wherein the first SEI NAL unit is seiNalUnitB.

[0297] 10. The method according to any one of solutions 1 to 9, wherein the second SEI NAL unit is seiNalUnitA.

[0298] Referring to the first, second, and third sets of solutions listed above, in some embodiments, the video includes 360-degree video. In some embodiments, the conversion includes encoding the video into a bitstream. In some embodiments, the conversion includes decoding the bitstream to generate pixel values ​​for the video.

[0299] Some embodiments may include a video decoding apparatus that includes a processor configured to implement the methods described in the first, second, or third solution list.

[0300] Some embodiments may include a video encoding apparatus that includes a processor configured to implement one or more of the methods described in solutions 1 to 8.

[0301] In some embodiments, a method for storing a bitstream representing a video to a computer-readable recording medium may be implemented. The method includes generating a bitstream from the video according to the methods described in any one or more of the solutions above; and storing the bitstream in a computer-readable recording medium.

[0302] Some embodiments may include a computer-readable medium that stores a bitstream generated according to any one or more of the solutions described above.

[0303] Some embodiments may include a computer program product having computer code stored thereon, which, when executed by a processor, causes the processor to implement any of the methods described above.

[0304] 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 combinations thereof. 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 memory device, a material composition that enables machine-readable propagation signals, or combinations thereof. The term "data processing apparatus" encompasses all means, devices, and machines for processing data, including, for example, programmable processors, computers, or multiple processors or computers. In addition to hardware, the apparatus may also include code that creates an execution environment for the computer program in question, such as code constituting processor firmware, a protocol stack, a database management system, an operating system, or combinations thereof. Propagation signals are artificially generated signals, such as machine-generated electrical, optical, or electromagnetic signals, generated to encode information for transmission to a suitable receiver device.

[0305] 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 standalone programs or modules, components, subroutines, or other units suitable for use in 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 coordinating files (e.g., a file storing one or more modules, subroutines, or portions of code). Computer programs can be deployed to execute on a single computer or multiple computers located in one location or distributed across multiple locations and interconnected via a communication network.

[0306] The processes and logic flows described in this specification can be executed by one or more programmable processors to execute one or more computer programs, thereby performing functions by manipulating input data and generating output. The processes and logic flows can also be executed by dedicated logic circuitry, and the device can be implemented as dedicated logic circuitry, such as an FPGA (Field-Programmable Gate Array) or an ASIC (Application-Specific Integrated Circuit).

[0307] Processors suitable for executing computer programs include, for example, general-purpose and special-purpose microprocessors, and any one or more processors of any kind of digital computer. Typically, a 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 memory 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 one or more mass storage devices, 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 memory devices, including, for example, semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and memory may be supplemented by or incorporated into special-purpose logic circuitry.

[0308] Although this patent document contains numerous details, these details should not be construed as limiting the scope of any subject matter or claimable content, but rather as a description of features that may be specific to particular embodiments of a particular technology. Certain features described in this patent document in the context of individual embodiments 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 separately in multiple embodiments or in any suitable sub-combination. Furthermore, although features may be described above as functioning in certain combinations and even initially claimed in this way, in some cases one or more features from the claimed combination may be removed from the combination, and the claimed combination may involve sub-combinations or variations of sub-combinations.

[0309] Similarly, although operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring such operations to be performed in the specific order shown or in a sequential order, or to perform all shown operations to achieve 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.

[0310] Only some implementation methods and examples are described, and other implementation methods, enhancements and variations may be made based on the content described and shown in this patent document.

Claims

1. A method for processing video data, comprising: Perform the conversion between the video and the video bitstream. According to the rules, the bitstream comprises one or more layers, each layer comprises one or more images, and each image comprises one or more sub-images. The rule specifies that when the second SEI NAL unit meets the conditions, one or more processes of the first Supplemental Enhanced Information Network Abstraction Layer (SEI NAL) unit of the target output sub-image sub-bitstream extracted during the sub-image sub-bitstream extraction process are performed, and the second SEI NAL unit is removed from the target output sub-image sub-bitstream. The one or more processes include generating the first SEI NAL unit. The one or more processes include: adding the first SEI NAL unit to an image unit that includes the second SEI NAL unit, immediately following the second SEI NAL unit. The one or more processes include: extracting scalable nested SEI messages from scalable nested SEI messages, and including the extracted scalable nested SEI messages as non-scalable nested SEI messages in the first SEI NAL unit.

2. The method of claim 1, wherein the conditions include: (a) the target output sub-picture sub-bitstream includes the second SEI NAL unit, the second SEI NAL unit including scalable nested SEI messages; (b) a first syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message in the scalable nested SEI message applies to the same set of output layers as the target output sub-picture sub-bitstream; and a second syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message applied to a specified set of output layers or layers applies only to a specific sub-picture of the specified set of output layers or layers; and (c) the scalable nested SEI message applies to a set of layers and sub-pictures that are the same as the target output sub-picture sub-bitstream.

3. The method according to claim 1, wherein, The conditions include: (a) the number of layers in the output layer set that is the same as the set of layers in the target output sub-picture sub-bitstream is equal to 1; (b) the target output sub-picture sub-bitstream includes the second SEI NAL unit, the second SEI NAL unit includes scalable nested SEI messages; (c) the first syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message in the scalable nested SEI message applies to the same layer as in the target output sub-picture sub-bitstream; and the second syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message applied to the specified output layer set or layer applies only to a specific sub-picture of the specified output layer set or layer; and (d) the scalable nested SEI message applies to the same layer and sub-picture as in the target output sub-picture sub-bitstream.

4. The method of claim 1, wherein the conditions include: (a) the list of layers in the target output sub-image sub-bitstream does not include all layers in the bitstream; (b) the target output sub-image sub-bitstream includes scalable nested SEI messages; and wherein, The processing includes keeping the first SEINAL unit of the target output sub-image sub-bitstream unchanged.

5. The method according to claim 1, wherein, The first SEI NAL unit is seiNalUnitB.

6. The method according to claim 1, wherein, The second SEI NAL unit is seiNalUnitA.

7. The method according to claim 1, wherein, The video includes 360-degree video.

8. The method according to any one of claims 1 to 7, wherein, The conversion includes encoding the video into the bitstream.

9. The method according to any one of claims 1 to 7, wherein, The conversion includes decoding the bitstream to generate pixel values ​​for the video.

10. An apparatus for processing video data, comprising a processor and a non-transitory memory having instructions thereon, wherein, When the instruction is executed by the processor, the processor: Perform the conversion between the video and the video bitstream. According to the rules, the bitstream comprises one or more layers, each layer comprises one or more images, and each image comprises one or more sub-images. The rule specifies that when the second SEI NAL unit meets the conditions, one or more processes of the first Supplemental Enhanced Information Network Abstraction Layer (SEI NAL) unit of the target output sub-image sub-bitstream extracted during the sub-image sub-bitstream extraction process are performed, and the second SEI NAL unit is removed from the target output sub-image sub-bitstream. The one or more processes include generating the first SEI NAL unit. The one or more processes include: adding the first SEI NAL unit to an image unit that includes the second SEI NAL unit, immediately following the second SEI NAL unit. The one or more processes include: extracting scalable nested SEI messages from scalable nested SEI messages, and including the extracted scalable nested SEI messages as non-scalable nested SEI messages in the first SEI NAL unit.

11. The apparatus according to claim 10, wherein, The first SEI NAL unit is seiNalUnitB, and the second SEI NAL unit is seiNalUnitA.

12. The apparatus according to claim 10, wherein, The conditions include: (a) the target output sub-picture sub-bitstream includes the second SEI NAL unit, the second SEI NAL unit includes scalable nested SEI messages; (b) a first syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message in the scalable nested SEI message applies to the same set of output layers as the target output sub-picture sub-bitstream; and a second syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message applied to a specified set of output layers or layers applies only to a specific sub-picture of the specified set of output layers or layers; and (c) the scalable nested SEI message applies to the same set of layers and sub-pictures as the target output sub-picture sub-bitstream.

13. The apparatus according to claim 10, wherein, The conditions include: (a) the number of layers in the output layer set that is the same as the set of layers in the target output sub-picture sub-bitstream is equal to 1; (b) the target output sub-picture sub-bitstream includes the second SEI NAL unit, the second SEI NAL unit includes scalable nested SEI messages; (c) the first syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message in the scalable nested SEI message applies to the same layer as in the target output sub-picture sub-bitstream; and the second syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message applied to the specified output layer set or layer applies only to a specific sub-picture of the specified output layer set or layer; and (d) the scalable nested SEI message applies to the same layer and sub-picture as in the target output sub-picture sub-bitstream.

14. A non-transitory computer-readable storage medium storing instructions that cause a processor to: Perform the conversion between the video and the video bitstream. in, According to the rules, the bitstream comprises one or more layers, each layer comprises one or more images, and each image comprises one or more sub-images. The rule specifies that when the second SEI NAL unit meets the conditions, one or more processes of the first Supplemental Enhanced Information Network Abstraction Layer (SEI NAL) unit of the target output sub-image sub-bitstream extracted during the sub-image sub-bitstream extraction process are performed, and the second SEI NAL unit is removed from the target output sub-image sub-bitstream. The one or more processes include generating the first SEI NAL unit. The one or more processes include: adding the first SEI NAL unit to an image unit that includes the second SEI NAL unit, immediately following the second SEI NAL unit. The one or more processes include: extracting scalable nested SEI messages from scalable nested SEI messages, and including the extracted scalable nested SEI messages as non-scalable nested SEI messages in the first SEI NAL unit.

15. The non-transitory computer-readable storage medium according to claim 14, wherein, The first SEI NAL unit is seiNalUnitB, and the second SEI NAL unit is seiNalUnitA.

16. The non-transitory computer-readable storage medium according to claim 14, wherein, The conditions include: (a) the target output sub-picture sub-bitstream includes the second SEI NAL unit, the second SEI NAL unit includes scalable nested SEI messages; (b) a first syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message in the scalable nested SEI message applies to the same set of output layers as the target output sub-picture sub-bitstream; and a second syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message applied to a specified set of output layers or layers applies only to a specific sub-picture of the specified set of output layers or layers; and (c) the scalable nested SEI message applies to the same set of layers and sub-pictures as the target output sub-picture sub-bitstream; or, The conditions include: (a) the number of layers in the output layer set that is the same as the set of layers in the target output sub-image sub-bitstream is equal to 1; (b) the target output sub-image sub-bitstream includes the second SEI NAL unit, the second SEINAL unit includes scalable nested SEI messages; (c) the first syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message in the scalable nested SEI message applies to the same layer as the target output sub-image sub-bitstream; and the second syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message applied to the specified output layer set or layer applies only to a specific sub-image of the specified output layer set or layer; and (d) the scalable nested SEI message applies to the same layer and sub-image as the target output sub-image sub-bitstream.

17. A non-transitory computer-readable recording medium storing a bitstream of computer instructions and video, wherein, When the computer instructions are executed by the video processing device, a method for processing video data is implemented to generate the bitstream, wherein the method includes: Generate the bitstream of the video. According to the rules, the bitstream comprises one or more layers, each layer comprises one or more images, and each image comprises one or more sub-images. The rule specifies that when the second SEI NAL unit meets the conditions, one or more processes of the first Supplemental Enhanced Information Network Abstraction Layer (SEI NAL) unit of the target output sub-image sub-bitstream extracted during the sub-image sub-bitstream extraction process are performed, and the second SEI NAL unit is removed from the target output sub-image sub-bitstream. The one or more processes include generating the first SEI NAL unit. The one or more processes include: adding the first SEI NAL unit to an image unit that includes the second SEI NAL unit, immediately following the second SEI NAL unit. The one or more processes include: extracting scalable nested SEI messages from scalable nested SEI messages, and including the extracted scalable nested SEI messages as non-scalable nested SEI messages in the first SEI NAL unit.

18. The non-transitory computer-readable recording medium according to claim 17, wherein, The first SEI NAL unit is seiNalUnitB, and the second SEI NAL unit is seiNalUnitA.

19. The non-transitory computer-readable recording medium according to claim 17, wherein, The conditions include: (a) the target output sub-picture sub-bitstream includes the second SEI NAL unit, the second SEI NAL unit includes scalable nested SEI messages; (b) a first syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message in the scalable nested SEI message applies to the same set of output layers as the target output sub-picture sub-bitstream; and a second syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message applied to a specified set of output layers or layers applies only to a specific sub-picture of the specified set of output layers or layers; and (c) the scalable nested SEI message applies to the same set of layers and sub-pictures as the target output sub-picture sub-bitstream; or, The conditions include: (a) the number of layers in the output layer set that is the same as the set of layers in the target output sub-image sub-bitstream is equal to 1; (b) the target output sub-image sub-bitstream includes the second SEI NAL unit, the second SEINAL unit includes scalable nested SEI messages; (c) the first syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message in the scalable nested SEI message applies to the same layer as the target output sub-image sub-bitstream; and the second syntax field in the scalable nested SEI message is equal to a value indicating that the scalable nested SEI message applied to the specified output layer set or layer applies only to a specific sub-image of the specified output layer set or layer; and (d) the scalable nested SEI message applies to the same layer and sub-image as the target output sub-image sub-bitstream.

20. A method for storing a video bitstream, comprising: Generate the bitstream of the video, and The bitstream is stored in a non-transitory computer-readable recording medium; According to the rules, the bitstream comprises one or more layers, each layer comprises one or more images, and each image comprises one or more sub-images. The rule specifies that when the second SEI NAL unit meets the conditions, one or more processes of the first Supplemental Enhanced Information Network Abstraction Layer (SEI NAL) unit of the target output sub-image sub-bitstream extracted during the sub-image sub-bitstream extraction process are performed, and the second SEI NAL unit is removed from the target output sub-image sub-bitstream. The one or more processes include generating the first SEI NAL unit. The one or more processes include: adding the first SEI NAL unit to an image unit that includes the second SEI NAL unit, immediately following the second SEI NAL unit. The one or more processes include: extracting scalable nested SEI messages from scalable nested SEI messages, and including the extracted scalable nested SEI messages as non-scalable nested SEI messages in the first SEI NAL unit.

21. A video decoding apparatus, comprising a processor configured to implement the method of any one of claims 1 to 7 and 9.

22. A video encoding apparatus comprising a processor configured to implement the method of any one of claims 1 to 8.

Images