Transform skip residual coding

Abstract

Several techniques for video encoding and video decoding are described. An example method includes performing a conversion between a block of a video and a bitstream of the video according to a rule. The rule provides that a presence of a syntax flag indicating whether transform skip residual coding is enabled at a video unit level in the bitstream is based on values of a first syntax element indicating a use of sign data hiding in the video unit and a second syntax element indicating a use of dependent quantization in the video unit.

Description

[0001] Cross-reference to related applications

[0002] This application is based on International Patent Application No. PCT / CN2021 / 088056, filed on April 19, 2021, which claims priority and interest in International Patent Application No. PCT / CN2020 / 085489, filed on April 19, 2020. All of the aforementioned patent applications are incorporated herein by reference in their entirety. Technical Field

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

[0004] Digital video accounts for the largest share of bandwidth usage on 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 the codec representation of video using control information useful for decoding the codec representation.

[0006] In one example aspect, a video processing method is disclosed. The method includes performing a conversion between a video image and a video bitstream according to rules. The rules specify that at least one of the scaling window offsets applied to the video image is allowed to be negative.

[0007] In another example, a video processing method is disclosed. This method includes performing a conversion between video blocks and a video bitstream according to rules. The rules specify whether transform skipping residual encoding / decoding is enabled at the video unit level, and whether a syntax flag exists in the bitstream based on the values ​​of a first syntax element indicating the use of symbolic data hiding in the video unit and a second syntax element indicating the use of associated quantization in the video unit.

[0008] In another example, a video processing method is disclosed. This method includes performing a conversion between a video and a video bitstream according to rules. The rules specify that the maximum number of syntax elements supporting sub-block-based merge motion vector prediction candidates, defined by a sequence parameter set subtracted from 5, is in the range of 0 to N (inclusive), where N is an integer equal to 5 minus the value of a syntax flag indicating whether a sub-block-based temporal motion vector predictor is enabled for the conversion.

[0009] In another example, a video processing method is disclosed. This method includes performing a conversion between videos comprising one or more video images, wherein the codec representation conforms to a format rule; wherein the format rule specifies that two or more syntax fields in a sequence parameter set control the reference image resolution (RPR) variation in the video.

[0010] In another example, a different video processing method is disclosed. This method includes performing a conversion between videos comprising one or more video images, wherein the codec representation conforms to a format rule; wherein the format rule specifies that a single syntax field in a sequence parameter set controls the reference image resolution (RPR) variation in the video; and wherein the format rule specifies that resampling of the inter-frame layer reference image is permitted for use in the conversion, regardless of the value of the single syntax field.

[0011] In another example, a different video processing method is disclosed. This method includes performing a transformation between videos comprising one or more layers, each layer comprising one or more video images, each video image comprising one or more sub-images, wherein the codec representation conforms to a format rule; wherein the format rule specifies a first constraint on cross-layer alignment or a second constraint on a combination of scalability of sub-images and inter-frame layer images.

[0012] In another example, a different video processing method is disclosed. This method includes performing a transformation between videos comprising one or more layers, each layer comprising one or more video images, each video image comprising one or more sub-images, wherein the transformation conforms to a format rule that prohibits inter-frame layer reference images or long-term reference images from being used as juxtaposed images of the current image used for the transformation.

[0013] In another example, a different video processing method is disclosed. This method includes performing a conversion between a video comprising multiple images and its codec representation, wherein the conversion conforms to a rule stipulating that for any two images within a codec video sequence of the same codec layer or a codec video sequence having the same values ​​for pic_width_in_luma_samples and pic_height_in_luma_samples, the values ​​of each of scaling_win_left_offset, scaling_win_right_offset, scaling_win_top_offset, and scaling_win_bottom_offset are identical.

[0014] In another example, a different video processing method is disclosed. This method includes performing a conversion between a video comprising multiple images and a codec representation of that video, wherein the conversion conforms to a rule that specifies that inter-frame layer prediction is allowed only if the current image is an intra-frame random access point image, provided that the image resolution or scaling window differs for the current image and other images in the same access unit.

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

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

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

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

[0019] 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.

[0020] Figure 2 The image is shown as an example of rectangular strip segmentation, where the image is divided into 24 slices (6 slice columns and 4 slice rows) and 9 rectangular strips.

[0021] Figure 3 The image shown is divided into slices and rectangular strips, with the image divided into 4 slices (2 slice columns and 2 slice rows) and 4 rectangular strips.

[0022] Figure 4 The image is displayed as being divided into 15 slices, 24 strips, and 24 sub-images.

[0023] Figure 5 This is a block diagram of an example video processing system.

[0024] Figure 6 This is a block diagram of a video processing device.

[0025] Figure 7 A flowchart of an example method for video processing.

[0026] Figure 8 This is a block diagram illustrating a video encoding / decoding system according to some embodiments of the present disclosure.

[0027] Figure 9This is a block diagram illustrating an encoder according to some embodiments of the present disclosure.

[0028] Figure 10 This is a block diagram illustrating a decoder according to some embodiments of the present disclosure.

[0029] Figure 11 An example of a typical sub-picture-based viewport-dependent 360° video encoding / decoding scheme is shown.

[0030] Figure 12 A viewport-dependent 360° video encoding and decoding scheme based on sub-images and spatial scalability is shown.

[0031] Figure 13 This is a flowchart representation of a video processing method according to the present technology.

[0032] Figure 14 This is a flowchart representation of another video processing method according to the present technology.

[0033] Figure 15 This is a flowchart representation of another video processing method according to the present technology. Detailed Implementation

[0034] The use of chapter headings in this document is for ease of understanding and does not limit the applicability of the techniques and embodiments disclosed in each chapter to that chapter only. Furthermore, the use of H.266 terminology in some descriptions is merely for ease of understanding and not to limit the scope of the disclosed techniques. Therefore, the techniques described herein are also applicable to other video codec protocols and designs. In this document, edit changes to text relative to the current draft of the VVC specification are indicated by strikethrough to indicate canceled text and highlighting to indicate added text (including bold and italics).

[0035] 1. Overview

[0036] This document relates to video codec techniques. Specifically, it concerns 1) combinations of two or more of the following in video codecs: Reference Picture Resampling (RPR), subpictures, and scalability; 2) the use of RPR between the current picture and a reference picture with the same spatial resolution; and 3) combinations of long-term reference pictures and juxtaposed pictures. These ideas can be applied individually or in various combinations to any video codec standard or non-standard video codec that supports multi-layer video codecs (e.g., the Multi-Functional Video Codec (VVC) under development).

[0037] 2. Abbreviation

[0038] APS Adaptive Parameter Set

[0039] AU Access Unit

[0040] AUD Access Unit Separator

[0041] AVC Advanced Video Codec

[0042] CLVS codec layer video sequence

[0043] CCALF Cross-Component Adaptive Loop Filter

[0044] CPB image buffer

[0045] CRA Clean Random Access

[0046] CTU (Codec Tree Unit)

[0047] CVS codec video sequence

[0048] DCI decoding capability information

[0049] DPB Decoding Image Buffer

[0050] EOB bitstream end

[0051] EOS sequence ends

[0052] GDR Gradual Decoding and Refresh

[0053] HEVC High-Efficiency Video Encoding and Decoding

[0054] HRD Assumption Reference Decoder

[0055] IDR Instant Decoding and Refresh

[0056] ILP Inter-Frame Prediction

[0057] ILRP True Gradient Reference Image

[0058] IRAP Intra-Frame Random Access Images

[0059] JEM Joint Exploration Model

[0060] LTRP Long-Term Reference Image

[0061] MCTS Motion Constraint Pieces

[0062] NAL Network Abstraction Layer

[0063] OLS Output Layer Set

[0064] PH image header

[0065] PPS Image Parameter Set

[0066] PTL (Level, Grade, Class)

[0067] PU Image Unit

[0068] RAP Random Access Point

[0069] RBSP raw byte sequence payload

[0070] SEI Supplemental Enhancement Information

[0071] SPS Sequence Parameter Set

[0072] STRP Short-Term Reference Image

[0073] SVC Scalable Video Codec

[0074] VCL (Video Codec Layer)

[0075] VPS Video Parameter Set

[0076] VTM VVC Test Model

[0077] VUI Video Availability Information

[0078] VVC Multi-Functional Video Encoding and Decoding

[0079] 3. Preliminary Discussion

[0080] Video codec standards have primarily evolved through the development of well-known ITU-T and ISO / IEC standards. ITU-T developed the H.261 and H.263 standards, while ISO / IEC developed the MPEG-1 and MPEG-4 Visual standards. The two organizations jointly developed the H.262 / MPEG-2 video standard, the H.264 / MPEG-4 Advanced Video Codec (AVC) standard, and the H.265 / HEVC standard. Starting with H.262, video codec standards are based on a hybrid video codec architecture, utilizing temporal prediction plus transform coding. To explore future video codec technologies beyond HEVC, the Joint Video Exploration Team (JVET) was jointly established by VCEG and MPEG in 2015. Since then, JVET has adopted many new methods and incorporated them into reference software called the Joint Exploration Model (JEM). JVET meetings are held quarterly, and the goal of new codec standards is to reduce the bitrate by 50% compared to HEVC. The new video codec standard was officially named Multifunctional Video Coding (VVC) at the JVET meeting in April 2018, and the first version of the VVC Test Model (VTM) was also released at that time. With ongoing efforts to standardize VVC, new codec technologies have been adopted into the VVC standard at each JVET meeting. The VVC working draft and test model VTM are updated after each meeting. The current goal of the VVC project is to achieve Technical Completion (FDIS) at the meeting in July 2020.

[0081] 3.1. Image Segmentation Schemes in HEVC

[0082] HEVC includes four different image segmentation schemes: regular striping, non-independent striping, slice, and wavefront parallel processing (WPP). These can be applied to maximum transmission unit (MTU) size matching, parallel processing, and reduction of end-to-end latency.

[0083] Regular slices are similar to those in H.264 / AVC. Each regular slice is encapsulated in its own NAL unit, and intra-frame prediction (intra-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).

[0084] Regular striping is the only tool available for parallelization, and it is available in almost the same form in H.264 / AVC. Parallelization based on regular striping requires minimal inter-processor or inter-core communication (except for inter-processor or inter-core data sharing for motion compensation during decoding prediction of encode-decode images, which is typically much heavier than inter-processor or inter-core data sharing due to intra-frame image prediction). However, for the same reason, using regular striping can incur 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, regular striping (compared to other tools mentioned below) can also serve as a key mechanism for bitstream segmentation to match MTU size requirements. In many cases, the goals of parallelization and MTU size matching are contradictory in terms of stripe layout requirements within the image. The implementation of such situations led to the development of the parallelization tools mentioned below.

[0085] Non-independent striping has a short stripe header and allows the bitstream to be split at tree block boundaries without disrupting any intra-picture predictions. Essentially, non-independent striping divides a regular stripe into multiple NAL units, reducing end-to-end latency by allowing a portion of the regular stripe to be sent before the entire regular stripe's encoding is complete.

[0086] In WPP, images are segmented into single-row codec tree blocks (CTBs). Entropy decoding and prediction are allowed to utilize data from CTBs in other segments. Parallel processing is possible through parallel decoding of CTB rows, where the decoding of a CTB row begins with a delay of two CTBs to ensure that data associated with CTBs above and to the right of the main CTB is available before the main CTB being decoded. Using this staggered start (which looks like a wavefront when represented graphically), as many processors / cores as images containing CTB rows can be parallelized. Because intra-image prediction is allowed between neighboring tree block rows within an image, the inter-processor / inter-core communication required to achieve intra-image prediction can be substantial. WPP segmentation does not result in additional NAL units compared to segmentation without WPP application, 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.

[0087] A slice is defined by 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.

[0088] Before decoding the top left CTB of the next slice in the order of the slice raster scans of the image, the scan order of the CTBs is changed to the local scan order within the slice (according to the order of the slice's CTB raster scans). Similar to regular stripes, slices break the intra-image prediction dependency and the entropy decoding dependency. However, they do not need to be contained in separate NAL units (the 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 in the case of a stripe spanning multiple slices, the inter-processor / inter-core communication required for intra-image prediction between processing units decoding neighboring slices is limited to transmitting the shared stripe header and loop filtering associated with the sharing of reconstructed samples and metadata. When a stripe contains more than one slice or WPP segment, the entry point byte offset of each slice or WPP segment in the stripe, except for the first one, is signaled in the stripe header.

[0089] For simplicity, restrictions are specified in HEVC for the application of four different image segmentation schemes. For most profiles specified in HEVC, a given codec video sequence cannot contain both slices and wavefronts simultaneously. 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, then that strip must end within the same CTB line.

[0090] With recent modifications to HEVC, HEVC has specified three SEI messages related to MCT: the Instantaneous MCTS SEI message, the MCTS Extracted Message Set SEI message, and the MCTS Extracted Message Nested SEI message.

[0091] The temporal MCTS SEI message indicates the presence of an MCTS in the bitstream and signals this 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 temporal motion vector predictions from blocks outside the MCTS are not allowed. This allows each MCTS to be decoded independently even if no slices are included in the MCTS.

[0092] The MCTS Extraction Information Set (SEI) message provides supplementary information that can be used for MCTS sub-bitstream extraction (specified as part of the SEI message's semantics) to generate a bitstream conforming to 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 to be used during the MCTS sub-bitstream extraction process. When extracting the 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 syntax elements related to the slice address (including first_slice_segment_in_pic_flag and slice_segment_address) typically need to have different values.

[0093] 3.2. Image Segmentation in VVC

[0094] 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 covering a rectangular area of ​​the image. The CTUs within a slice are scanned in raster scan order within that slice.

[0095] A strip consists of an integer number of complete slices or an integer number of consecutive complete CTU lines within a slice of an image.

[0096] Two stripe modes are supported: raster scan stripe mode and rectangular stripe mode. In raster scan stripe mode, a stripe contains a complete stripe sequence within a sheet raster scan of the image. In rectangular stripe mode, a stripe contains multiple complete sheets that together form a rectangular area of ​​the image, or multiple consecutive complete CTU rows of a sheet that together forms a rectangular area of ​​the image. Sheets within a rectangular stripe are scanned in sheet raster scan order within the rectangular area corresponding to that stripe.

[0097] A sub-image contains one or more stripes that collectively cover a rectangular area of ​​the image.

[0098] 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.

[0099] 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 slices.

[0100] 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.

[0101] Figure 4 An example of sub-image segmentation of an image is shown, where the image is segmented into 18 pieces: 12 pieces on the left (each covering a strip with 4x4 CTUs) and 6 pieces on the right (each covering two vertically stacked strips with 2x2 CTUs), resulting in a total of 24 strips and 24 sub-images of different sizes (each strip being a sub-image).

[0102] 3.3. Image resolution variations within a sequence

[0103] In AVC and HEVC, the spatial resolution of an image cannot be changed unless a new sequence with a new SPS begins with an IRAP image. VVC allows changing the image resolution within a sequence at locations where IRAP images are not encoded; IRAP images are always intra-frame encoded and decoded. This feature is sometimes called Reference Image Resampling (RPR) because it requires resampling the reference image used for inter-frame prediction when the reference image has a different resolution than the current image being decoded.

[0104] The scaling ratio is limited to greater than or equal to 1 / 2 (2x downsampling from the reference image to the current image) and less than or equal to 8 (8x upsampling). Three sets of resampling filters with different frequency cutoffs are specified to handle various scaling ratios between the reference and current images. The three sets of resampling filters are applied to scaling ratios ranging from 1 / 2 to 1 / 1.75, from 1 / 1.75 to 1 / 1.25, and from 1 / 1.25 to 8, respectively. Each set of resampling filters has 16 phases for luma and 32 phases for chroma, similar to the case for motion-compensated interpolation filters. In fact, the normal MC interpolation process is a special case of the resampling process where the scaling ratio ranges from 1 / 1.25 to 8. The horizontal and vertical scaling ratios are derived based on the image width and height, as well as the left, right, top, and bottom scaling offsets specified for the reference and current images.

[0105] Other aspects of VVC designs that support this feature, unlike HEVC, include: i) signaling the image resolution and corresponding consistency window in the PPS instead of the SPS, while in the SPS the signaling indicates the maximum image resolution. ii) for a single-layer bitstream, each image storage (the slot in the DPB used to store one decoded image) occupies the buffer size required to store the decoded image with the maximum image resolution.

[0106] 3.4. Scalable Video Codec (SVC) in General and VVC

[0107] Scalable video codec (SVC, sometimes also called 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 base quality level. One or more enhancement layers can carry additional video data to support, for example, higher spatial, temporal, and / or signal-to-noise ratio (SNR) levels. Enhancement layers can be defined relative to previously encoded 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., a layer that is neither the lowest nor the highest layer) can be an EL of a layer below the intermediate layer (e.g., a base layer or any intermediate enhancement layer) and simultaneously used as an RL of one or more enhancement layers above the intermediate layer. Similarly, in the Multiview or 3D extension of the HEVC standard, multiple views may exist, 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).

[0108] In SVC, the parameters used by the encoder or decoder are grouped into parameter sets based on the codec level in which they can be used (e.g., video level, sequence level, picture level, stripe level, etc.). For example, parameters that can be used by one or more codec video sequences at different layers in a bitstream can be included in the Video Parameter Set (VPS), and parameters that can be 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 strip can be included in the stripe header. Likewise, indications of which parameter set(s) a particular layer uses at a given time can be provided at various codec levels.

[0109] Because of VVC's support for Reference Picture Resampling (RPR), support for multi-layered bitstreams can be designed without requiring any additional signaling notification processing level codec tools. For example, two layers in VVC with SD and HD resolutions can be supported because the upsampling required for spatial scalability can be achieved using only RPR upsampling filters. However, supporting scalability requires a higher level of syntax changes (compared to not supporting scalability at all). Scalability support was specified in VVC version 1. Unlike scalability support in any earlier video codec standards, including extensions to AVC and HEVC, VVC scalability was designed to be as friendly as possible to single-layer decoder designs. The decoding capability of multi-layered bitstreams is specified as if there were only a single layer in the bitstream. For example, decoding capabilities such as DPB size are specified in a way that is independent of the number of layers in the bitstream to be decoded. Essentially, decoders designed for single-layered bitstreams do not require many changes to decode multi-layered bitstreams. Compared to the multi-layered 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.

[0110] 3.5. Viewport-dependent 360° video stream based on sub-images

[0111] In 360° video (also known as omnidirectional video) streaming, at any given moment, only a subset of the entire omnidirectional video sphere (e.g., the current viewport) is presented to the user, who can at any time rotate their head to change their viewing orientation, thus changing the current viewport. While it's desirable to have at least some lower-quality representations of areas not covered by the current viewport on the client side, ready to be presented to the user in case they suddenly change their viewing orientation to any location on the sphere, the high-quality representation of the omnidirectional video is only needed for the current viewport being presented to the user. This optimization can be achieved by dividing the high-quality representation of the entire omnidirectional video into sub-pictures with appropriate granularity. Using VVC, these two representations can be encoded as two independent layers.

[0112] A typical sub-image-based viewport-dependent 360° video transmission scheme is as follows: Figure 11 As shown, the higher resolution representation of the complete video consists of sub-pictures, while the lower resolution representation of the complete video does not use sub-pictures and can be encoded using random access points with a lower frequency, as shown in the higher resolution representation. The client receives the lower resolution complete video, while for the higher resolution video, it only receives and decodes the sub-pictures covering the current viewport.

[0113] 3.6. Parameter Set

[0114] AVC, HEVC, and VVC specify parameter sets. Parameter set types include SPS, PPS, APS, and VPS. All AVC, HEVC, and VVC versions 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.

[0115] SPS is designed to carry sequence-level header information, and PPS is designed to carry infrequently changing image-level header information. Using SPS and PPS eliminates the need to repeat infrequently changing information for each sequence or image, thus avoiding redundant signaling notifications. Furthermore, using SPS and PPS enables out-of-band transmission of critical header information, thereby not only avoiding redundant transmission but also improving error recovery capabilities.

[0116] The purpose of introducing a VPS is to carry sequence-level header information common to all layers in a multi-layer bitstream.

[0117] The purpose of APS is to carry such image-level or stripe-level information, which requires a considerable number of bits for encoding and decoding, can be shared by multiple images, and can have many different variations in the sequence.

[0118] The following are the semantics of SPS / PPS / APS in some embodiments:

[0119] sps_seq_parameter_set_id provides an identifier for SPS to reference by other syntax elements.

[0120] Regardless of the nuh_layer_id value, SPS NAL cells share the same value space as sps_seq_parameter_set_id.

[0121] Let spsLayerId be the nuh_layer_id value of a specific SPS NAL cell, and vclLayerId be the nuh_layer_id value of a specific VCLNAL cell. A specific VCL NAL cell should not reference a specific SPSNAL cell unless spsLayerId is less than or equal to vclLayerId and the decoded OLS contains both a layer with nuh_layer_id equal to spsLayerId and a layer with nuh_layer_id equal to vclLayerId.

[0122] The pps_pic_parameter_set_id identifies the PPS referenced by other syntax elements. The value of pps_pic_parameter_set_id should be in the range of 0 to 63 (inclusive).

[0123] Regardless of the nuh_layer_id value, PPS NAL units share the same value space for pps_pic_parameter_set_id.

[0124] Let ppsLayerId be the value of numh_layer_id for a specific PPS NAL unit, and vclLayerId be the value of numh_layer_id for a specific VCL NAL unit. A specific VCL NAL unit should not refer to a specific PPS NAL unit unless ppsLayerId is less than or equal to vclLayerId and the decoded OLS contains both a layer with nuh_layer_id equal to ppsLayerId and a layer with nuh_layer_id equal to vclLayerId.

[0125] The adaptation_parameter_set_id provides an identifier for APS for reference by other syntax elements.

[0126] When aps_params_type is equal to ALF_APS or SCALING_APS, the value of adaptation_parameter_set_id should be in the range of 0 to 7 (inclusive).

[0127] When aps_params_type equals LMCS_APS, the value of adaptation_parameter_set_id should be in the range of 0 to 3 (inclusive).

[0128] Let apsLayerId be the nuh_layer_id value of a specific APS NAL unit, and vclLayerId be the nuh_layer_id value of a specific VCL NAL unit. A specific VCL NAL unit should not reference a specific APS NAL unit unless apsLayerId is less than or equal to vclLayerId, and the decoded OLS contains both layers with nuh_layer_id equal to apsLayerId and layers with nuh_layer_id equal to vclLayerId.

[0129] 3.7. Sub-bit Stream Extraction Process

[0130] The inputs to this process are the bitstream inBitstream, the target OLS index targetOlsIdx, and the highest target TemporalId value tIdTarget.

[0131] The output of this process is the sub-bit stream outBitstream.

[0132] The requirement for bitstream consistency of the input bitstream is that any output sub-bitstream that satisfies all of the following conditions should be a compliant bitstream:

[0133] – The output sub-bitstream is the output of the process specified in this clause, where, as input, the bitstream targetOlsIdx is equal to the index of the list of OLS specified by the VPS, and tIdTarget is equal to any value in the range of 0 to 6 (inclusive).

[0134] – The output sub-bitstream contains at least one VCLNAL unit whose nuh_layer_id is equal to each nuh_layer_id value in LayerIdInOls[targetOlsIdx].

[0135] – The output sub-bitstream contains at least one VCL NAL unit with TemporalId equal to tIdTarget. Note: A valid bitstream contains one or more encoded / decoded stripe NAL units with TemporalId equal to 0, but does not necessarily contain encoded / decoded stripe NAL units with nuh_layer_id equal to 0. The output sub-bitstream OutBitstream is exported as follows:

[0136] – The outBitstream setting is the same as the inBitstream setting.

[0137] Remove all NAL cells from outBitstream whose TemporalId is greater than tIdTarget.

[0138] – Remove all NAL units from outBitstream whose nal_unit_type is not equal to any of VPS_NUT, DCI_NUT, and EOB_NUT and whose nuh_layer_id is not included in the list LayerIdInOls[targetOlsIdx].

[0139] Remove all NAL units from outBitstream where all of the following conditions are true:

[0140] –nal_unit_type is not equal to IDR_W_RADL, IDR_N_LP or CRA_NUT.

[0141] – For values ​​of j in the range of 0 to NumLayersInOls[targetOlsIdx]-1 (inclusive), nuh_layer_id is equal to LayerIdInOls[targetOlsIdx][j].

[0142] –TemporalId is greater than or equal to NumSubLayersInLayerInOLS[targetOlsIdx][j].

[0143] – Remove all SEI NAL cells from outBitstream that contain scalable nested SEI messages with nesting_ols_flag equal to 1 and no i value in the range from 0 to nesting_num_olss_minus1 (inclusive), such that NestingOlsIdx[i] equals targetOlsIdx.

[0144] – When LayerIdInOls[targetOlsIdx] does not include all values ​​of nuh_layer_id in all NAL units of the bitstream, the following applies:

[0145] Remove all SEI NAL units from outBitstream that contain non-scalable nested SEI messages with payloadType equal to 0 (buffer cycle) or 130 (decoding unit information).

[0146] – When general_same_pic_timing_in_all_ols_flag equals 0, remove all SEI NAL units from outBitstream that contain non-scalable nested SEI messages (picture timing) with payloadType equal to 1.

[0147] – When outBitstream contains SEI NAL units and is applied to outBitstream (NestingOlsIdx[i] equals targetOlsIdx), and these units contain scalable nested SEI messages with nesting_ols_flag equal to 1, the following applies:

[0148] – If same_pic_timing_within_ols_flag equals 0, extract the appropriate non-scalable nested SEI messages with payloadType equal to 0 (buffer cycle), 1 (picture timing), or 130 (decoding unit information) from the scalable nested SEI messages, and include these SEI messages in outBitstream.

[0149] - Otherwise (same_pic_timing_within_ols_flag equals 1), extract the appropriate non-scalable nested SEI messages with payloadType equal to 0 (buffer cycle) or 130 (decoding unit information) from the scalable nested SEI messages, and include these SEI messages in the outBitstream.

[0150] 4. The technical problem solved by the disclosed technical solution

[0151] The existing design in the latest VVC documentation has the following issues:

[0152] 1) Current VVC designs support typical encoding and decoding schemes for 360° video, such as... Figure 11 As shown. However, although scalability is supported in current VVC designs, it is not supported as... Figure 12 The improved 360-degree video encoding and decoding scheme is shown. (Compared to...) Figure 11 The only difference between the methods shown is that inter-frame layer prediction (ILP) is applied to the method described above. Figure 12 The method shown in the figure.

[0153] The following two places in the VVC draft do not allow the combination of sub-images and spatial scalability:

[0154] a. The spatial scalability design of VVC relies on RPR features. However, the combination of RPR and sub-images is currently prohibited by the following semantic constraints:

[0155] When res_change_in_clvs_allowed_flag equals 1, the value of subpic_info_present_flag should be equal to 0.

[0156] Therefore, the improved encoding and decoding scheme is not allowed because, for SPS referenced by a higher layer, the above constraints do not allow setting subpic_info_present_flag to 1 (to use multiple subpics per picture) while setting res_change_in_clvs_allowed_flag to 1 (to enable RPR, which is required for the spatial scalability of ILP).

[0157] b. The current VVC draft imposes the following constraints on the combination of sub-images and scalability:

[0158] When subpic_treatment_as_pic_flag[i] equals 1, the bitstream consistency requirement is that for each output layer and its reference layer in an OLS that includes the layer containing the i-th subpic as the output layer, all of the following conditions are true:

[0159] – All images in the output layer and its reference layer should have the same value for pic_width_in_luma_samples and pic_height_in_luma_samples.

[0160] – For each j value in the range of 0 to sps_num_subpics_minus1 (inclusive), all SPS referenced by the output layer and its reference layer should have the same value of sps_num_subpics_minus1, and should have the same values ​​of subpic_ctu_top_left_x[j], subpic_ctu_top_left_y[j], subpic_width_minus1[j], subpic_height_minus1[j], and loop_filter_across_subpic_enabled_flag[j], respectively.

[0161] For each j value in the range of 0 to sps_num_subpics_minus1 (inclusive), all pictures in each access unit of the output layer and its reference layer should have the same value of SubpicIdVal[j].

[0162] Apart from the restricted combination of sub-images and SNR scalability, the above constraints essentially do not allow any other combination of sub-images and ILP scalability, where each layer within a dependency tree must have the same spatial resolution and the same sub-image layout.

[0163] 2) When `subpic_treatment_as_pic_flag[i]` equals 1, the subpicture boundary of the i-th subpicture will be considered as the picture boundary in motion compensation. In the VVC draft text, this is achieved by applying certain cropping operations during the decoding process related to motion compensation. However, for Figure 12 The improved encoding and decoding scheme shown does not require such cropping in this case, since the lower layers are fully available to the decoder and not just the region corresponding to the i-th sub-image, thus avoiding unnecessary encoding and decoding efficiency loss.

[0164] 3) Not considering Figure 12 With the support of the improved encoding / decoding scheme shown, the existing constraints on the combination of sub-images and ILP scalability (described in the description of Problem 1b) have the following problems:

[0165] a. This constraint should also apply when the layer containing the i-th sub-image is not an output layer of OLS. The entire constraint should be specified in a way that does not consider whether the layer is an output layer of OLS.

[0166] b. It should include the requirement for cross-layer alignment of the value of subpic_treated_as_pic_flag[i], otherwise it will be impossible to extract subpicture sequences with the same index across layers.

[0167] c. The requirement for cross-layer alignment of the value of loop_filter_across_subpic_enabled_flag[i] should be eliminated because regardless of the value of this flag, as long as subpic_treated_as_pic_flag[i] is equal to 1, the subpic sequence can be extracted. The setting of the value of loop_filter_across_subpic_enabled_flag[i] should be left to the encoder to determine the trade-off between the quality of a single extractable subpic sequence and the quality of multiple sets of extractable subpic sequences, just as these two flags are signaled independently of each other.

[0168] d. The entire constraint should only be applied when sps_num_subpics_minus1 is greater than 0, to avoid unintentionally covering one subpic at a time for each subpic in all cases.

[0169] e. The time domain to which the constraints apply needs to be clearly defined, for example, a set of AUs.

[0170] f. This should include requirements for cross-layer alignment of the values ​​of each scaling window parameter scaling_win_left_offset, scaling_win_right_offset, scaling_win_top_offset, and scaling_win_bottom_offset to ensure that ITRP's RPR is not needed when each image has multiple sub-images.

[0171] 4) Currently, the juxtaposed image of the current image can be a Long-Term Reference Image (LTRP) at the same layer as the current image, or it can be an Inter-Layer Reference Image (ILRP), such as a reference image at a different layer than the current image. However, in either case, motion vector scaling based on Proof-of-Concept (POC) will not be applied, so the encoding / decoding performance resulting from allowing this is expected to be very low. Therefore, it is best to prevent the juxtaposed image of the current image from being an LTRP or an ILRP.

[0172] 5) Currently, images with the same spatial resolution in CLVS are allowed to have different scaling windows. However, this should not be allowed; otherwise, the SPS flag and general constraint flags of RPR would not be able to be used to completely disable the RPR tool.

[0173] 6) Currently, when performing sub-bitstream extraction, parameter sets (SPS / PPS / VPS) of layers not included in the current / target OLS can also be included in the extracted bitstream. However, it is not by design that as long as an OLS containing both layer A and layer B is defined in the VPS, even if layer A and layer B are not included in the current OLS being decoded, the stripes in layer A referencing the parameter set in layer B is not intended.

[0174] 7) The number of allowed APSs depends on the APS type. However, the signaling notification for the APS ID is fixed at u(5), regardless of the allowed APSs, which may waste unnecessary bits.

[0175] 8) Currently, the scaling window offset is signaled as a positive value, thus only positive vertical and horizontal offsets are supported. However, it is possible to allow signaling of negative scaling window offsets, thereby deriving negative vertical and horizontal offsets even when the reference picture does not include the scaling window. Allowing scaling factors greater than 1 would also benefit subpicture use cases in 360° video encoding / decoding, such as a base layer with full 360° video content but a lower resolution, and subsequent enhancements to specific viewports encoded at higher resolution (like zooming in from a picture in the base layer). However, several places in the current specification should be modified to support this functionality.

[0176] 9) Currently, when Transform Skip Residual Coding (TSRC) is enabled, Symbol Data Hiding (SDH) and Correlated Quantization (DQ) can also be used, which violates the concept of lossless coding and decoding. TSRC is a mode that encodes and decodes the quantization indexes of all scan positions of the transform block. SDH is a coding and decoding technique that omits symbols with non-zero indices. DQ is a mode where the quantization of a sample depends on the state of the previous sample.

[0177] 5. List of technical solutions and embodiments

[0178] To address the aforementioned and other issues, the following summarized methods are disclosed. These items should be considered as examples for explaining general concepts, and not interpreted in a narrow way. Furthermore, these items can be used individually or in combination in any way.

[0179] 1) To address issue 1a, instead of having only one SPS flag (e.g., res_change_in_clvs_allowed_flag as in the current VVC draft) to control RPR, multiple (e.g., two) SPS flags can be specified and / or signaled for this purpose.

[0180] a. For example, the first flag (e.g., ref_pic_resampling_enabled_flag) specifies whether RPR is required to decode one or more images, while the second flag (e.g., res_change_in_clvs_allowed_flag) specifies whether changing the image resolution within CLVS is allowed.

[0181] b. Alternatively, the second flag may be signaled only if the first flag indicates that RPR may be needed to decode one or more images. Furthermore, when no signaling is given, the value of the second flag is inferred to indicate that changing the image resolution within the CLVS is not permitted.

[0182] i. Alternatively, the two flags can signal each other independently.

[0183] c. Alternatively, add a more general constraint flag such that there exists a general constraint flag for each of the first and second flags.

[0184] d. In addition, combinations of multiple sub-pictures for each picture where RES_change_in_clvs_allowed_flag is equal to 1 are not allowed, but combinations of multiple sub-pictures for each picture where ref_pic_resampling_enabled_flag is equal to 1 are allowed.

[0185] e. Furthermore, the constraint on the value of scaling_window_explicit_signaling_flag based on the value of res_change_in_clvs_allowed_flag is changed to be based on the value of ref_pic_resampling_enabled_flag, as follows: when ref_pic_resampling_enabled_flag When the value is 0, the value of scaling_window_explicit_signalling_flag should be 0.

[0186] f. Alternatively, one or all of multiple (e.g., two) flags can be signaled in the VPS instead of the SPS.

[0187] i. In one example, one or all of the multiple (e.g., two) flags in a VPS may be applied to all tiers specified by the VPS.

[0188] ii. In another example, one or all of the multiple (e.g., two) flags in a VPS may each have multiple instances of signaling notification in the VPS, and each instance applies to all layers in a dependency tree.

[0189] g. In one example, each of the multiple flags is encoded as an unsigned integer using l bits u(1).

[0190] h. Alternatively, a non-binary value (e.g., in SPS / VPS) can be used to signal a syntax element to specify the use of RPR during decoding and the allowance for image resolution changes within CLVS.

[0191] i. In one example, when the value of a syntax element is equal to 0, it specifies that RPR is not required to decode one or more images.

[0192] ii. In one example, when the value of the syntax element is equal to 1, it specifies that RPR may be used to decode one or more images, and does not allow changing the image resolution within CLVS.

[0193] iii. In one example, when the value of the syntax element is equal to 2, it specifies that RPR may be used to decode one or more images, while allowing the image resolution to be changed within CLVS.

[0194] iv. Alternatively, how signaling informs syntax elements may depend on whether inter-frame layer prediction is allowed.

[0195] v. In one example, the syntax element is encoded using ue(v), which indicates the syntax element of the left-first unsigned integer 0-order Exp-Golomb encoding.

[0196] vi. In another example, the syntax element is encoded as an unsigned integer using N bits u(N), for example, where N equals 2.

[0197] 2) Alternatively, in addition to item 1 used to address problem 1a, there could still be only one flag, such as res_change_in_clvs_allowed_flag, but the semantics could be changed so that resampling of inter-layer reference images is allowed regardless of the value of the flag.

[0198] a. In one example, the semantics can be changed as follows: `res_change_in_clvs_allowed_flag` equal to 1 indicates that the image spatial resolution can be changed within the CLVS of the reference SPS. A value of 0 for `res_change_in_clvs_allowed_flag` indicates that the spatial resolution of the image will not change within any CLVS referenced to the SPS.

[0199] b. With this change, even when res_change_in_clvs_allowed_flag equals 0, the decoding of sub-pictures / pictures can still use the RPR of the Inter-Frame Layer Reference Picture (ILRP).

[0200] 3) To address problem 1b, the constraint on the combination of sub-image and ILP scalability was updated so that the constraint only imposes cross-layer alignment constraints on the current layer and all higher layers that depend on the current layer, and not on higher or lower layers that do not depend on the current layer.

[0201] a. Alternatively, update the constraints to apply cross-layer alignment constraints only to the current layer and all layers above the current layer.

[0202] b. Alternatively, update the constraints to apply cross-layer alignment constraints only to the current layer and all higher layers in each OLS that contains the current layer.

[0203] c. Alternatively, update the constraints to apply cross-layer alignment constraints only to the current layer and all lower layers that serve as the reference layer for the current layer.

[0204] d. Alternatively, update the constraints to apply cross-layer alignment constraints only to the current layer and all layers below it.

[0205] e. Alternatively, update the constraints to apply cross-layer alignment constraints only to the current layer and all lower layers in each OLS that contains the current layer.

[0206] f. Alternatively, update the constraints to apply cross-layer alignment restrictions only to all layers below the highest layer.

[0207] g. Alternatively, update the constraints to apply cross-layer alignment restrictions only to all layers above the lowest layer.

[0208] 4) To address issue 2, in one or more decoding processes involving cropping operations in the inter-frame prediction correlation process used to process sub-image boundaries in motion compensation / motion prediction as image boundaries (e.g., in the derivation process for temporal luma motion vector prediction in clause 8.5.2.11, the luma sample bilinear interpolation process in clause 8.5.3.2.2, the derivation process for sub-block-based temporal merge candidates in clause 8.5.5.3, the derivation process for sub-block-based temporal merge underlying motion data in clause 8.5.5.4, the derivation process for constructed affine control point motion vector merge candidates in clause 8.5.6.3.2, the luma sample interpolation filtering process in clause 8.5.6.3.3, the luma integer sample acquisition process in clause 8.5.6.3.4, and the chromaticity sample interpolation process in clause 8.5.6.3.4), the following changes are applied:

[0209] a. In one example, the process is modified so that if subpic_treatment_as_pic_flag[CurrSubpicIdx] equals 1 and the reference image refPicLX has a sps_num_subpics_minus1 greater than 0, then the clipping operation is applied; otherwise, the clipping operation is not applied.

[0210] i. Alternatively, when the juxtaposed images are not allowed to be ILRP, as described above, only change the process of the reference image refPicLX not being a juxtaposed image, and do not change the process of the reference image refPicLX being a juxtaposed image.

[0211] b. In one example, the process is modified so that if `subpic_treatment_as_pic_flag[CurrSubpicIdx]` equals 1 and the current stripe's `nal_unit_type` value is not equal to `IDR_W_RADL`, `IDR_N_LP`, or `CRA_NUT`, then a cropping operation is applied; otherwise, no cropping operation is applied. Additionally, ILP is only permitted for encoding and decoding IRAP images.

[0212] c. In one example, these decoding processes are not changed. For example, if subpic_treated_as_pic_flag[CurrSubpicIdx] equals 1, the cropping operation is applied; otherwise, the cropping operation is not applied, just like in the current VVC text.

[0213] 5) To address problem 3a, update the constraint on the combination of scalability of sub-images and ILPs so that the constraint imposes cross-layer alignment restrictions on all layers in each dependency tree. The dependency tree contains a specific layer, all layers that use that specific layer as a reference layer, and all reference layers of that specific layer, regardless of whether any of these layers is an output layer of the OLS.

[0214] 6) To address problem 3b, the constraint on the combination of subpic and ILP scalability was updated so that the constraint imposed a cross-layer alignment constraint on the value of subpic_treatment_as_pic_flag[i].

[0215] 7) To address problem 3c, the constraint on the combination of subpic and ILP scalability was updated so that the constraint does not impose cross-layer alignment restrictions on the value of loop_filter_across_subpic_enabled_flag[i].

[0216] 8) To address the 3D issue, the constraints on the combination of subpics and ILP scalability were updated so that the constraints do not apply when sps_num_subpics_minus1 equals 0.

[0217] a. Alternatively, update the constraints so that they do not apply when subpic_info_present_flag equals 0.

[0218] 9) To address problem 3e, the constraints on the combination of sub-image and ILP scalability were updated so that the constraints impose cross-layer alignment restrictions on images in AUs of a specific target group.

[0219] a. In one example, for each CLVS of the current layer of the reference SPS, assume that the AUtargetAuSet of the target group is all the AUs from the AU containing the first picture of the CLVS in decoding order to the AU containing the last picture of the CLVS in decoding order (including end values).

[0220] 10) To address problem 3f, update the constraints on the combination of sub-image and ILP scalability such that the constraints impose cross-layer alignment restrictions on the values ​​of each of the scaling window parameters scaling_win_left_offset, scaling_win_right_offset, scaling_win_top_offset, and scaling_win_bottom_offset.

[0221] 11) To solve problem 4, constrain the juxtaposed image of the current image to not be a long-term reference image (LTRP).

[0222] a. Alternatively, constrain the juxtaposed image of the current image to not be an inter-layer reference image (ILRP).

[0223] b. Alternatively, constrain the juxtaposed images of the current image to be neither LTRP nor ILRP.

[0224] c. Alternatively, if the juxtaposed image of the current image is LTRP or ILRP, scaling should not be applied to obtain the motion vector pointing to the juxtaposed image.

[0225] 12) To solve problem 5, the value of each of scaling_win_left_offset, scaling_win_right_offset, scaling_win_top_offset, and scaling_win_bottom_offset must be the same for any two images within the same CLVS that have the same values ​​of pic_width_in_luma_samples and pic_height_in_luma_samples, respectively.

[0226] a. Alternatively, replace "within the same CLVS" with "within the same CVS" above.

[0227] b. Alternatively, the constraints are as follows:

[0228] Let ppsA and ppsB be any two PPSs referencing the same SPS. The requirement for bitstream consistency is that when ppsA and ppsB have the same values ​​for pic_width_in_luma_samples and pic_height_in_luma_samples, respectively, ppsA and ppsB should also have the same values ​​for scaling_win_left_offset, scaling_win_right_offset, scaling_win_top_offset, and scaling_win_bottom_offset, respectively.

[0229] c. Alternatively, the constraints are as follows:

[0230] The values ​​of scaling_win_left_offset, scaling_win_right_offset, scaling_win_top_offset, and scaling_win_bottom_offset should be identical for any two images within the same CVS, and should satisfy all of the following conditions:

[0231] i. The two images have the same values ​​for pic_width_in_luma_samples and pic_height_in_luma_samples, respectively.

[0232] ii. Two images belong to the same layer or two layers, where one layer is a reference layer for the other.

[0233] 13) It was proposed that when the image resolution / scaling window is different for the current image and other images in the same access unit, ILP should only be allowed if the current image is an IRAP image.

[0234] 14) In this document, image resolution may refer to the width and / or height of the image, or the width and / or height and / or top-left corner position of the image's zoom window and / or consistency window.

[0235] 15) In this document, not using RPR may mean that any reference image of the current image has the same resolution as the current image.

[0236] 16) Regarding the bitstream extraction for problem 6, one or more of the following solutions are proposed:

[0237] a. In one example, to export the output sub-bitstream, remove the parameter set (e.g., SPS / PPS / APS NAL unit) that has nuh_layer_id not included in the list LayerIdInOls[t argetOlsIdx].

[0238] b. For example, the derivation of the output sub-bitstream OutBitstream may depend on one or more of the following:

[0239] i. Remove all NAL units from outBitstream whose nal_unit_type is equal to SPS_NUT and whose nuh_layer_id is not included in the list LayerIdInOls[targetOlsIdx].

[0240] ii. Remove all NAL units from outBitstream whose nal_unit_type is equal to PPS_NUT and whose nuh_layer_id is not included in the list LayerIdInOls[targetOlsIdx].

[0241] iii. Remove all NAL units from outBitstream whose nal_unit_type is equal to APS_NUT and whose nuh_layer_id is not included in the list LayerIdInOls[targetOlsIdx].

[0242] iv. Remove all NAL units from outBitstream whose nal_unit_type is equal to any one of SPS_NUT, PPS_NUT, and APS_NUT and for which any of the following conditions are true:

[0243] 1. For at least one j value in the range of 0 to NumLayersInOls[targetOlsIdx]-1 (inclusive), nuh_layer_id is greater than LayerIdInOls[targetOlsIdx][j].

[0244] 2. nuh_layer_id is not included in the list LayerIdInOls[targetOlsIdx].

[0245] v. When the first NAL unit, whose nal_unit_type is equal to any one of SPS_NUT, PPS_NUT, and APS_NUT, is removed during extraction, the second NAL unit referencing the first NAL unit should also be removed.

[0246] c. For example, the derivation of the output sub-bitstream OutBitstream may depend on one or more of the following:

[0247] i. Remove all NAL units from outBitstream whose nal_unit_type is equal to any of VPS_NUT, DCI_NUT, and EOB_NUT and whose nuh_layer_id is not included in the list LayerIdInOls[targetOlsIdx].

[0248] 17) The bits required for signaling notification of the APS ID (e.g., adaptation_parameter_set_id) depend on the APS type.

[0249] a. The bits required for signaling notification of APS ID (e.g., adaptation_parameter_set_id) are changed from u(3) to u(v).

[0250] i. In one example, for an adaptive loop filter (ALF) APS, the APS ID can be encoded and decoded using u(a).

[0251] ii. In one example, for a luminance map with chroma scaling (LMCS), the APS ID can be encoded and decoded using u(b).

[0252] iii. In one example, for a scaled list APS, the APS ID can be encoded and decoded using u(c).

[0253] iv. In one example, a / b / c depends on the maximum allowed number of APS of the corresponding type.

[0254] 1. In one example, a>b and a>c.

[0255] 2. In one example, a >= b and a > c.

[0256] 3. In one example, c > b.

[0257] 4. In one example, b = 2.

[0258] 5. In one example, c = 3.

[0259] 6. In one example, a = 3 or greater than 3 (e.g., 4, 5, 6, 7, 8, 9).

[0260] 18) The encoding / decoding order of APS ID (e.g., adaptation_parameter_set_id) and APS type (e.g., aps_params_type in VVC text) is switched so that the APS type appears before the APS ID in the bitstream.

[0261] 19) The total number of filters allowed in APS can be limited based on encoding / decoding information, such as image / strip type, encoding / decoding structure (dual tree or single tree), and layer information.

[0262] a. The total number of filters allowed in an APS can include the total number of ALFs in all APS NAL units with PUs and the total number of luminance / chrominance ALFs and CC-ALFs in the APS.

[0263] b. The total number of filters allowed in the APS may include the total number of adaptive loop filter classes for the luminance component (or luminance ALF filter), the total number of alternative filters for the chrominance component (chrominance ALF filter), and / or the total number of cross-component filters in all APS NAL units with PU.

[0264] 20) Regarding the scaling factor greater than 1 in solving the eighth problem, one or more solutions are proposed as follows:

[0265] a. In one example, the scaling window offset applied to the image size for scaling ratio calculation can be negative.

[0266] i. For example, syntax elements for scaling window offsets (e.g., scaling_win_left_offset, scaling_win_right_offset, scaling_win_top_offset, scaling_win_bottom_offset) can be encoded and decoded using signed binarization, such as ae(v), f(n), i(n), se(v), etc.

[0267] b. In one example, how the scaling window offset is constrained based on the image size (e.g., image width / height) may depend on whether the scaling window offset is negative.

[0268] i. For example, the constraints between offset and image width / height can vary depending on whether the scaling window offset is negative.

[0269] 1. For example, one or more constraints can be specified based on whether both the left and right offsets are negative, and / or whether one of the left and right offsets is negative / positive, and / or whether both the left and right offsets are positive.

[0270] 2. For example, one or more constraints can be specified based on whether both the top and bottom offsets are negative, and / or whether one of the top and bottom offsets is negative / positive, and / or whether both the top and bottom offsets are positive.

[0271] ii. For example, the value of the scaling window offset is limited based on the image size only when the value of the scaling window offset is positive or 0.

[0272] 1. For example, when scaling_win_left_offset and scaling_win_right_offset are not negative (or positive), the value of SubWidthC*(scaling_win_left_offset+scaling_win_right_offset) should be less than pic_width_in_luma_samples.

[0273] 2. For example, when scaling_win_top_offset and scaling_win_bottom_offset are not negative (or positive), the value of SubHeightC*(scaling_win_top_offset+scaling_win_bottom_offset) should be less than pic_height_in_luma_samples.

[0274] iii. For example, absolute offsets can be used to specify constraints.

[0275] 1. For example, the value of SubWidthC*(abs(scaling_win_left_offset)+abs(scaling_win_right_offset)) should be less than X1*pic_width_in_luma_samples, where X1 is a positive integer, such as X1>=1.

[0276] 2. For example, the value of SubHeightC*(abs(scaling_win_top_offset)+abs(scaling_win_bottom_offset)) should be less than X2*pic_height_in_luma_samples, where X2 is a positive integer, such as X2>=1.

[0277] iv. Alternatively, do not constrain the offset value on the image width / height when any scaling window offset value is negative (e.g., treat negative offsets as 0-value offsets).

[0278] 1. For example, the value of SubWidthC*(max(0,scaling_win_left_offset)+max(0,scaling_win_right_offset)) should be less than pic_width_in_luma_samples.

[0279] 2. For example, the value of SubHeightC*(max(0,scaling_win_top_offset)+max(0,scaling_win_bottom_offset)) should be less than pic_height_in_luma_samples.

[0280] c. In one example, how bitstream consistency / constraints are performed between the reference image output width / height, the current image output width / height, the reference image width / height, the current image width / height, and the maximum image width / height (e.g., refPicOutputWidthL, refPicOutputHeightL, PicOutputWidthL, PicOutputHeightL, refPicWidthInLumaSamples, refPicHeightInLumaSamples, pic_width / height_in_luma_samples, pic_width / height_max_in_luma_samples) can depend on whether the scaling window offset value is negative.

[0281] d. In one example, how the width / height of the exported image (e.g., PicOutputWidthL, PicOutputHeightL) is exported may depend on whether the scaling window offset value is negative.

[0282] i. For example, when the scaling offset of the reference image is negative, it can be treated as a 0-value offset to calculate the width / height of the output image of the reference image.

[0283] ii. For example, the variable PicOutputWidthL can be derived as follows: PicOutputWidthL = pic_width_in_luma_samples - SubWidthC * (max(0, scaling_win_right_offset) + max(0, scaling_win_left_offset)).

[0284] iii. The variable PicOutputHeightL can be derived as follows: PicOutputHeightL=pic_height_in_luma_samples-SubWidthC*(max(0,scaling_win_bottom_offset)+max(0,scaling_win_top_offset)).

[0285] e. In one example, how fractional sample interpolation is performed may depend on whether the value of the scaling window offset is negative.

[0286] i. For example, when the scaling window offset of the reference image is negative, it can be treated as a 0-value offset for motion compensation.

[0287] 1. For example, the variable fRefLeftOffset can be set to equal to ((SubWidthC*max(0,scaling_win_left_offset))<<10), where scaling_win_left_offset is the scaling_win_left_offset of the reference image.

[0288] 2. For example, the variable fRefTopOffset can be set to equal to ((SubWidthC*max(0,scaling_win_top_offset))<<10), where scaling_win_top_offset is the scaling_win_top_offset of the reference image.

[0289] ii. For example, when the zoom window offset of the current image is negative, it can be treated as a 0-value offset for fractional sample interpolation.

[0290] 1. For example, suppose (refxSb) L ,refySb L ) represents the brightness position pointed to by the motion vector (refMvLX[0], refMvLX[1]) given in units of 1 / 16 samples. The variable refxSb L and refySb L It can be exported as follows:

[0291] a.refxSb L =(((xSb-(SubWidthC*max(0,scaling_win_left_offset)))<<4)+refMvLX[0])*scalingRatio[0]

[0292] b.refySb L =(((ySb-(SubWidthC*max(0,scaling_win_top_offset)))<<4)+refMvLX[1])*scalingRatio[1]

[0293] 2. For example, let (refxSb) C ,refySb C ) is the chromaticity position pointed to by the motion vector (refMvLX[0], refMvLX[1]) given in units of 1 / 32 samples. Variable refxSb C and refySb C The export is as follows:

[0294] a.refxSb C =(((xSb-(SubWidthC*max(0,scaling_win_left_offset))) / SubWidthC<<5)+refMvLX[0])*scalingRatio[0]+addX

[0295] b.refySb C =(((ySb-(SubWidthC*max(0,scaling_win_top_offset))) / SubHeightC<<5)+refMvLX[1])*scalingRatio[1]+addY21) Regarding the signaling notification for solving the ninth problem of TSRC / DQ / SHD, one or more solutions are proposed as follows:

[0296] a. In one example, at the video unit level (e.g., at the picture sequence / picture group / picture / strip level), the signaling notification of the Symbolic Data Hiding (SDH) and Related Quantization (DQ) enable / disable flags may depend on whether Transform Skip Residual Coding (TSRC) is enabled.

[0297] i. For example, whether TSRC is enabled (e.g., sps / pps / ph / slice_ts_residual_coding_disabled_flag) can be signaled before the enable / disable flags of SDH / DQ at the same level (e.g., named sps / pps / ph / slice_dep_quant_enabled_flag, sps / pps / ph / slice_sign_data_hiding_enabled_flag).

[0298] ii. For example, signaling notifications of SDH / DQ enable / disable flags at the SPS / PPS / PH / SH level (e.g., named SPS / PPS / PH / slice_dep_quant_enabled_flag, SPS / PPS / PH / slice_sign_data_hiding_enabled_flag) can be conditional on whether the TSRC is disabled at the same or higher level (e.g., whether SPS / PPS / PH / slice_ts_residual_coding_disabled_flag is equal to 1).

[0299] The syntax signaling in iii.SH (on top of JVET-Q2001-vE) can be modified as follows:

[0300]

[0301] iv. Additionally, it is inferred that if sps / pps / ph / slice_dep_quant_enabled_flag does not exist, it is equal to a certain value (e.g., 0).

[0302] v. Furthermore, it is inferred that sps / pps / ph / slice_sign_data_hiding_enabled_flag is equal to a certain value (e.g., 0) if it does not exist.

[0303] b. In one example, signaling can be used at the video unit level (e.g., at the sequence / picture group / picture / strip level) to indicate whether TSRC is enabled.

[0304] i. For example, a signaling notification in SPS / PPS / PH / SH may include a flag named (sps / pps / ph / slice)_ts_residual_coding_enabled_flag.

[0305] ii. Alternatively, signaling can be used at the video unit level (e.g., at the image sequence / image group / image / strip level) to notify whether TSRC is disabled.

[0306] iii. For example, a flag named (sps / pps / ph / slice)_ts_residual_coding_disabled_flag can be signaled in SPS / PPS / PH / SH.

[0307] c. In one example, based on transform skipping and whether DQ and SDH are enabled at the same or higher levels, a conditional signaling notification is made to indicate whether TSRC is enabled.

[0308] i. For example, conditional signaling notification of slice_ts_residual_coding_disabled_flag based on (sps_transform_skip_enabled_flag = 1 && !slice_dep_quant_enabled_flag && !slice_sign_data_hiding_enabled_flag).

[0309] ii. For example, conditionally signal ph_ts_residual_coding_disabled_flag based on (sps_transform_skip_enabled_flag = 1 && !ph_dep_quant_enabled_flag && !ph_sign_data_hiding_enabled_flag).

[0310] iii. For example, conditionally signal pps_ts_residual_coding_disabled_flag based on (sps_transform_skip_enabled_flag = 1 && !pps_dep_quant_enabled_flag && !pps_sign_data_hiding_enabled_flag).

[0311] iv. In the example above, sps_transform_skip_enabled_flag can be replaced with the SPS TSRC enable flag / SPS TSRC disable flag.

[0312] v. In the example above, sps_transform_skip_enabled_flag can be replaced with PPS TS enable flag / PPS TSRC enable flag / PPS TSRC disable flag.

[0313] d. In one example, whether to apply SDH or DQ in a block may depend on whether TS and / or TSRS are used.

[0314] e. In one example, when TS and / or TSRS are used in a block, SDH and / or DQ are not applied. ii. In one example, when TS and / or TSRS are used in a block, no signaling notification indicates whether SDH and / or DQ(multiple) SEs are used and it is inferred that they are not used.

[0315] f. In one example, if TS and / or TSRS are used in a block, then the constraint cannot use SDH and / or DQ.

[0316] 22) It may be necessary to scale the window offset (e.g., scaling_win_right_offset, scaling_win_left_offset, scaling_win_top_offset, scaling_win_bottom_offset) to be greater than (or not less than) an integer X, where X is negative.

[0317] a. In one example, X may depend on the image size.

[0318] 23) The variables PicOutputWidthL and PicOutputHeightL are derived as follows: PicOutputWidthL=pic_width_in_luma_samples-SubWidthC*(scaling_win_right_offset+scal ing_win_left_offset)PicOutputHeightL=pic_height_in_luma_samples-SubWidthC*(scaling_win_bottom_offset+scaling_win_top_offset).

[0319] Then one or more of the following restrictions can be applied:

[0320] a.((aX1*PicOutputWidthL+bX1)>>cX1)<=((dX1*X1+eX1)>>fX1), where X1 is a non-negative integer.

[0321] b.((aX0*PicOutputWidthL+bX0)>>cX0)>=((dX0*X1+eX0)>>fX0), where X0 is a non-negative integer.

[0322] c.((aY1*PicOutputHeightL+bY1)>>cY1)<=(dY1*Y1+eY1)>>fY1, where Y1 is a non-negative integer.

[0323] d.((aY0*PicOutputHeightL+bY0)>>cY0)<=(dY0*Y0+eY0)>>fY0, where Y0 is a non-negative integer.

[0324] e.((aXY1*PicOutputWidthL*PicOutputHeightL+bXY1)>>cXY1)<=(dXY1*XY1+eXY1)>>fXY1, where XY1 is a non-negative integer.

[0325] f.((aXY0*PicOutputWidthL*PicOutputHeightL+bXY0)>>cXY0)<=(dXY0*Y0+eXY0)>>fXY0, where XY0 is a non-negative integer.

[0326] In the above constraints, aX1, bX1, ..., eX1, fX1, aX0, bX0, ..., eX0, fX0, aY1, bY1, ..., eY1, fY1, aY0, bY0, ..., eY0, fY0, aXY1, bXY1, ..., eXY1, fXY1, aXY0, bXY0, ..., eXY0, fXY0 are all integers. In one example, aX1 = aX0 = aY1 = aY0 = aXY1 = aXY0 = 1, bX1 = bX0 = bY1 = bY0 = bXY1 = bXY0 = 0, cX1 = cX0 = cY1 = cY0 = cXY1 = cXY0 = 0, dX1 = dX0 = dY1 = dY0 = dXY1 = dXY0 = 1, eX1 = eX0 = eY1 = eY0 = eXY1 = eXY0 = 0, fX1 = fX0 = fY1 = fY0 = fXY1 = fXY0

[0327] h. In the above constraints, X1 and / or X0 may depend on pic_width_in_luma_samples.

[0328] i. In one example, X1 equals pic_width_in_luma_samples

[0329] ii. In one example, PicOutputWidthL <= pic_width_in_luma_samples*K, where K is a positive integer, such as 2, 3, 4, 5, 6, 7, 8.

[0330] i. In the above constraints, Y1 and / or Y0 may depend on pic_height_in_luma_samples.

[0331] i. In one example, Y1 equals pic_height_in_luma_samples

[0332] ii. In one example, PicOutputHeightL <= pic_height_in_luma_samples*K, where K is a positive integer, such as 2, 3, 4, 5, 6, 7, 8.

[0333] 24) In one example, the maximum allowed value of five_minus_max_num_subblock_merge_cand can be equal to X, where X is less than 5. For example, X = 4.

[0334] a. For example, `five_minus_max_num_subblock_merge_cand` specifies the maximum number of subblock-based merge motion vector prediction candidates supported from the SPS subtracted from 5. The value of `five_minus_max_num_subblock_merge_cand` should be in the range of 0 to 4 (inclusive). When it does not exist, the value of `five_minus_max_num_subblock_merge_cand` is inferred to be equal to 5.

[0335] 25) How to define the valid range of five_minus_max_num_subblock_merge_cand may depend on whether five_minus_max_num_subblock_merge exists.

[0336] a. For example, the valid range of five_minus_max_num_subblock_merge is defined only if five_minus_max_num_subblock_merge exists.

[0337] b. For example, different valid ranges of five_minus_max_num_subblock_merge are defined based on whether five_minus_max_num_subblock_merge exists.

[0338] c. For example, `five_minus_max_num_subblock_merge_cand` specifies the maximum number of subblock-based merge motion vector prediction candidates supported in the SPS, subtracted from 5. When `five_minus_max_num_subblock_merge_cand` exists, its value should be in the range of 0 to 5 – `sps_sbtmvp_enabled_flag` (inclusive). When it does not exist, its value is inferred to be equal to 5.

[0339] d. For example, `five_minus_max_num_subblock_merge_cand` specifies the maximum number of subblock-based merge motion vector prediction candidates supported in the SPS, subtracted from 5. When it does not exist, it is inferred that the value of `five_minus_max_num_subblock_merge_cand` is equal to 5. Otherwise (if `Five_minus_max_num_subblock_merge_cand` exists), the value of `five_minus_max_num_subblock_merge_cand` should be in the range of 0 to 5 – `sps_sbtmvp_enabled_flag` (inclusive). For example, `five_minus_max_num_subblock_merge_cand` specifies the maximum number of subblock-based merge motion vector prediction candidates supported in the SPS, subtracted from 5. When five_minus_max_num_subblock_merge_cand exists, its value should be in the range of 0 to 5 – sps_affine_enabled_flag (inclusive). When it does not exist, the value of five_minus_max_num_subblock_merge_cand is inferred to be equal to 5.

[0340] e. For example, `five_minus_max_num_subblock_merge_cand` specifies the maximum number of subblock-based merge motion vector prediction candidates supported in the SPS, subtracted from 5. When it does not exist, the value of `five_minus_max_num_subblock_merge_cand` is inferred to be equal to 5. Otherwise (if `five_minus_max_num_subblock_merge_cand` exists), the value of `five_minus_max_num_subblock_merge_cand` should be in the range of 0 to 5 – `sps_affine_enabled_flag` (inclusive).

[0341] f. For example, `five_minus_max_num_subblock_merge_cand` specifies the maximum number of subblock-based merge motion vector prediction candidates supported in the SPS, subtracted from 5. When `five_minus_max_num_subblock_merge_cand` exists, its value should be in the range of 0 to 4 (inclusive). When it does not exist, the value of `five_minus_max_num_subblock_merge_cand` is inferred to be equal to 5.

[0342] g. For example, `five_minus_max_num_subblock_merge_cand` specifies the maximum number of subblock-based merge motion vector prediction candidates supported in the SPS, subtracted from 5. When it does not exist, the value of `five_minus_max_num_subblock_merge_cand` is inferred to be equal to 5. Otherwise (if `five_minus_max_num_subblock_merge_cand` exists), the value of `five_minus_max_num_subblock_merge_cand` should be in the range of 0 to 4 (inclusive).

[0343] 6. Example

[0344] The following are some example embodiments of the inventions summarized in Section 5 of the previous article, which can be applied to the VVC specification. Most of the relevant parts that have been added or modified are... bold italics Underlined parts are used to indicate deletions, and some deleted parts are indicated by [[]].

[0345] 6.1. First Embodiment

[0346] This embodiment applies to items 1, 1.a, 1.b, 1.c, 1.d, 3, 4.ai, 5, 6, 7, 8, 9, 9.a, 10, 11 and 12b.

[0347] 7.3.2.3 Sequence Parameter Set Syntax

[0348]

[0349] 7.4.3.3 Sequence Parameter Set (RBSP) Semantics ...

[0351]

[0352] A value of 1 for `res_change_in_clvs_allowed_flag` indicates that the spatial resolution of the image can be changed within the CLVS of the reference SPS. A value of 0 for `res_change_in_clvs_allowed_flag` indicates that the spatial resolution of the image will not be changed within any CLVS of the reference SPS. ...

[0354] A subpic_treated_as_pic_flag[i] equal to 1 indicates that the i-th subpic of each encoded / decoded image in CLVS is treated as an image excluded from loop filtering during decoding. A subpic_treated_as_pic_flag[i] equal to 0 indicates that the i-th subpic of each encoded / decoded image in CLVS is not treated as an image excluded from loop filtering during decoding. When it does not exist, the value of subpic_treated_as_pic_flag[i] is inferred to be equal to sps_independent_subpics_flag.

[0355] when When subpic_treated_as_pic_flag[i] equals 1 The requirement for bitstream consistency is that, All of the following conditions are true.

[0356] All images should have the same values ​​for pic_width_in_luma_samples and pic_height_in_luma_samples.

[0357]

[0358] For each j value in the range from 0 to sps_num_subpics_minus1 (inclusive), All referenced SPSs should have subpic_ctu_top_left_x[j], subpic_ctu_top_left_y[j], subpic_width_minus1[j], subpic_height_minus1[j], and subpic_ctu_top_left_y[j], respectively. The same value for [[loop_filter_cross_subpic_enabled_flag[j],]].

[0359] For each j value in the range from 0 to sps_num_subpics_minus1 (inclusive), All images should have the same value for SubpicIdVal[j]. ...

[0361] 7.4.3.4 Image Parameter Set RBSP Semantics ...

[0363] A scaling_window_explicit_signaling_flag value of 1 indicates that the scaling window offset parameter exists in the PPS. A scaling_window_explicit_signaling_flag value of 0 indicates that the scaling window offset parameter does not exist in the PPS. When [[res_change_in_clvs_allowed_flag]] equals 0, the value of scaling_window_explicit_signaling_flag should also be 0.

[0364] `scaling_win_left_offset`, `scaling_win_right_offset`, `scaling_win_top_offset`, and `scaling_win_bottom_offset` specify the offsets of the image size applied to the scaling calculation. When these values ​​are not present, they are inferred to be equal to `pps_conf_win_left_offset`, `pps_conf_win_right_offset`, `pps_conf_win_top_offset`, and `pps_conf_win_bottom_offset`, respectively.

[0365] The value of SubWidthC*(scaling_win_left_offset+scaling_win_right_offset) should be less than pic_width_in_luma_samples, and the value of SubHeightC*(scaling_win_top_offset+scaling_win_bottom_offset) should be less than pic_height_in_luma_samples.

[0366]

[0367] The variables PicOutputWidthL and PicOutputHeightL are derived as follows:

[0368]

[0369]

[0370] Assume that refPicOutputWidthL and refPicOutputHeightL are the PicOutputWidthL and PicOutputHeightL of the reference image to the current image of this PPS, respectively. Bitstream consistency requires that all of the following conditions be met:

[0371] –PicOutputWidthL*2 should be greater than or equal to refPicWidthInLumaSamples.

[0372] –PicOutputHeightL*2 should be greater than or equal to refPicHeightInLumaSamples.

[0373] –PicOutputWidthL should be less than or equal to refPicWidthInLumaSamples*8.

[0374] –PicOutputHeightL should be less than or equal to refPicHeightInLumaSamples*8.

[0375] –PicOutputWidthL*pic_width_max_in_luma_samples should be greater than or equal to refPicOutputWidthL*(pic_width_in_luma_samples-Max(8,MinCbSizeY)). –PicOutputHeightL*pic_height_max_in_luma_samples should be greater than or equal to refPicOutputHeightL*(pic_height_in_luma_samples-Max(8,MinCbSizeY)). ...

[0377] 7.3.3.2 General Constraint Information Syntax

[0378]

[0379] 7.4.4.2 General Constraint Information Semantics ...

[0381]

[0382] A value of 1 for `no_res_change_in_clvs_constraint_flag` specifies that `res_change_in_clvs_allowed_flag` should be 0. A value of 0 for `no_res_change_in_clvs_constraint_flag` does not impose such a constraint. ...

[0384] 7.4.8.1 General Strip Header Semantics ...

[0386] A slice_collocated_from_l0_flag value of 1 specifies that the co-located image used for temporal motion vector prediction is derived from reference image list 0. A slice_collocated_from_l0_flag value of 0 specifies that the co-located image used for temporal motion vector prediction is derived from reference image list 1.

[0387] When slice_type equals B or P, ph_temporal_mvp_enabled_flag equals 1, and slice_collocated_from_l0_flag does not exist, the following applies:

[0388] --If rpl_info_in_ph_flag equals 1, then it is inferred that slice_collocated_from_l0_flag equals ph_collocated_from_l0_flag.

[0389] --Otherwise (rpl_info_in_ph_flag equals 0 and slice_type equals P), the value of slice_collocated_from_l0_flag is inferred to be equal to 1.

[0390] The slice_collocated_ref_idx specifies the reference index of the co-located image used for temporal motion vector prediction.

[0391] When slice_type equals P or when slice_type equals B and slice_collocated_from_l0_flag equals 1, slice_collocated_ref_idx references the entry in reference image list 0, and the value of slice_collocated_ref_idx should be in the range of 0 to NumRefIdxActive[0]–1 (inclusive).

[0392] When slice_type equals B and slice_collocated_from_l0_flag equals 0, slice_collocated_ref_idx references the entry in reference image list 1, and the value of slice_collocated_ref_idx should be in the range of 0 to NumRefIdxActive[1]–1 (inclusive).

[0393] The following applies when slice_collocated_ref_idx does not exist:

[0394] --If rpl_info_in_ph_flag equals 1, then it is inferred that the value of slice_collocated_ref_idx is equal to ph_collocated_ref_idx.

[0395] --Otherwise (rpl_info_in_ph_flag equals 0), the value of slice_collocated_ref_idx is inferred to be equal to 0.

[0396] The requirement for bitstream consistency is that the image referenced by slice_collocated_ref_idx should be identical across all slices of the encoded and decoded image.

[0397] The requirement for bitstream consistency is that the values ​​of pic_width_in_luma_samples and pic_height_in_luma_samples of the reference image referenced by slice_collocated_ref_idx should be equal to the values ​​of pic_width_in_luma_samples and pic_height_in_luma_samples of the current image, respectively, and RprConstraintsActive[slice_collocated_from_l0_flag? 0:1][slice_collocated_ref_idx] should be equal to 0.

[0398] 8.5.3.2.2 Bilinear Interpolation Process for Luminance Samples ...

[0400] For i = 0, the total sample unit (xInt) i ,yInt i The brightness position is exported as follows:

[0401] – If subpic_treated_as_pic_flag[CurrSubpicIdx] equals 1 The following applies:

[0402] xInt i =Clip3(SubpicLeftBoundaryPos,SubpicRightBoundaryPos,xInt L +i)(640)

[0403] yInt i=Clip3(SubpicTopBoundaryPos,SubpicBotBoundaryPos,yInt L +i) (641)

[0404] Otherwise, (subpic_treated_as_pic_flag[CurrSubpicIdx] equals 0)

[0405] The following applies:

[0406] xInt i =Clip3(0,picW-1,refWraparoundEnabledFlag?ClipH((PpsRefWraparoundOffset)*MinCbSizeY,picW,(xInt L +i)):xInt L +i) (642)

[0407] yInt i =Clip3(0,picH-1,yInt) L +i) (643) ...

[0409] 8.5.6.3.2 Luma Sample Interpolation Filtering Process ...

[0411] – If subpic_treatment_as_pic_flag[CurrSubpicIdx] equals 1 The following applies:

[0412] xInt i =Clip3(SubpicLeftBoundaryPos,SubpicRightBoundaryPos,xInt i (959)

[0413] yInt i =Clip3(SubpicTopBoundaryPos,SubpicBotBoundaryPos,yInt i (960)

[0414] Otherwise, (subpic_treatment_as_pic_flag[CurrSubpicIdx] equals 0) The following applies:

[0415] xInt i =Clip3(0,picW-1,refWraparoundEnabledFlag?ClipH((PpsRefWraparoundOffset)*MinCbSizeY,picW,xInt i ):xInt i (961)

[0416] yInt i =Clip3(0,picH-1,yInt) i (962) ...

[0418] 8.5.6.3.3 Luma Integer Sample Acquisition Process ...

[0420] The brightness position of the full sample unit (xInt, yInt) is exported as follows:

[0421] – If subpic_treatment_as_pic_flag[CurrSubpicIdx] equals 1 The following applies:

[0422] xInt=Clip3(SubpicLeftBoundaryPos,SubpicRightBoundaryPos,xInt L (968)

[0423] yInt=Clip3(SubpicTopBoundaryPos,SubpicBotBoundaryPos,yInt L (969)

[0424] -otherwise The following applies:

[0425]

[0426] yInt = Clip3(0, picH-1, yInt) L ) ...

[0428] 8.5.6.3.4 Chromaticity Sample Interpolation Process ...

[0430] – If subpic_treatment_as_pic_flag[CurrSubpicIdx] equals 1 Then the following applies:

[0431] xInt i =Clip3(SubpicLeftBoundaryPos / SubWidthC,SubpicRightBoundaryPos / SubWidthC,xInt i (977)

[0432] yInt i =Clip3(SubpicTopBoundaryPos / SubHeightC,SubpicBotBoundaryPos / SubHeightC,yInt i (978)

[0433] Otherwise, (subpic_treatment_as_pic_flag[CurrSubpicIdx] equals 0) The following applies:

[0434]

[0435] yInt i =Clip3(0,picH C -1,yInt i (980) ...

[0437] Alternatively, the highlighted part "and the reference image refPicLX's sps_num_subpics_minus1 is greater than 0" can be replaced with "and if the reference image refPicLX is an ILRP with the same spatial resolution as the current image".

[0438] Alternatively, the highlighted part “or the reference image refPicLX’s sps_num_subpics_minus1 is equal to 0” can be replaced with “or if the reference image refPicLX is an ILRP with a different spatial resolution than the current image”.

[0439] Alternatively, regarding the requirements for juxtaposed images, for example, "the requirement for bitstream consistency is that the image referenced by slice_collocated_ref_idx should be identical across all slices of the encoded / decoded image." "This can be replaced with "The requirement for bitstream consistency is that the image referenced by slice_collocated_ref_idx should be identical for all stripes of the encoded and decoded image." ".

[0440] Alternatively, regarding the requirements for juxtaposed images, for example, "the requirement for bitstream consistency is that the image referenced by slice_collocated_ref_idx should be identical across all slices of the encoded / decoded image." "This can be replaced with "The requirement for bitstream consistency is that the image referenced by slice_collocated_ref_idx should be identical for all stripes of the encoded and decoded image." .

[0441] 6.2. Second Embodiment

[0442] In some alternative embodiments, the following constraints of the first embodiment are applied:

[0443] when When subpic_treated_as_pic_flag[i] equals 1 The requirement for bitstream consistency is that, All of the following conditions are true.

[0444] All images should have the same values ​​for pic_width_in_luma_samples and pic_height_in_luma_samples.

[0445]

[0446] For each j value in the range from 0 to sps_num_subpics_minus1 (inclusive), All referenced SPSs should have subpic_ctu_top_left_x[j], subpic_ctu_top_left_y[j], subpic_width_minus1[j], subpic_height_minus1[j], and subpic_ctu_top_left_y[j], respectively.

[0447] The same value for [[loop_filter_cross_subpic_enabled_flag[j],]].

[0448] For each j value in the range from 0 to sps_num_subpics_minus1 (inclusive), All images should have the same value for SubpicIdVal[j].

[0449] Replace with one of the following:

[0450] 1) When When subpic_treated_as_pic_flag[i] equals 1 The requirement for bitstream consistency is that, All of the following conditions are true.

[0451] All images should have the same values ​​for pic_width_in_luma_samples and pic_height_in_luma_samples.

[0452]

[0453] For each j value in the range from 0 to sps_num_subpics_minus1 (inclusive), All referenced SPSs should have subpic_ctu_top_left_x[j], subpic_ctu_top_left_y[j], and subpic_width_minus1[j] respectively. The same value as subpic_height_minus1[j][[and loop_filter_cross_subpic_enabled_flag[j],]].

[0454] For each j value in the range from 0 to sps_num_subpics_minus1 (inclusive), All images should have the same value for SubpicIdVal[j].

[0455] 2) When When subpic_treated_as_pic_flag[i] equals 1 The requirement for bitstream consistency is that, All of the following conditions are true.

[0456] All images should have the same values ​​for pic_width_in_luma_samples and pic_height_in_luma_samples.

[0457]

[0458] For each j value in the range from 0 to sps_num_subpics_minus1 (inclusive), All referenced SPSs should have the same values ​​for subpic_ctu_top_left_x[j], subpic_ctu_top_left_y[j], subpic_width_minus1[j], subpic_height_minus1[j], and loop_filter_cross_subpic_enabled_flag[j].

[0459] For each j value in the range from 0 to sps_num_subpics_minus1 (inclusive), All images should have the same value for SubpicIdVal[j].

[0460] 3) When subpic_treated_as_pic_flag[i] equals 1, The requirement for bitstream consistency is that, All of the following conditions are true:

[0461] All images should have the same values ​​for pic_width_in_luma_samples and pic_height_in_luma_samples.

[0462]

[0463] For each j value in the range from 0 to sps_num_subpics_minus1 (inclusive), All referenced SPSs should have subpic_ctu_top_left_x[j], subpic_ctu_top_left_y[j], subpic_width_minus1[j], subpic_height_minus1[j], and subpic_ctu_top_left_y[j], respectively. The same value for [[loop_filter_cross_subpic_enabled_flag[j],]].

[0464] For each j value in the range from 0 to sps_num_subpics_minus1 (inclusive), All images should have the same value for SubpicIdVal[j].

[0465] 4) When When subpic_treated_as_pic_flag[i] equals 1 The requirement for bitstream consistency is that, All of the following conditions are true.

[0466] All images should have the same values ​​for pic_width_in_luma_samples and pic_height_in_luma_samples.

[0467]

[0468] For each j value in the range from 0 to sps_num_subpics_minus1 (inclusive), All referenced SPSs should have subpic_ctu_top_left_x[j], subpic_ctu_top_left_y[j], subpic_width_minus1[j], subpic_height_minus1[j], and subpic_ctu_top_left_y[j] respectively. Same value as loop_filter_cross_subpic_enabled_flag[j].

[0469] For each j value in the range from 0 to sps_num_subpics_minus1 (inclusive), All images should have the same value for SubpicIdVal[j].

[0470] 6.3. Third Embodiment

[0471] This example highlights the following limitations regarding the maximum number of ALF and CC-ALF filters:

[0472] 1) Replace the limit on the number of ALF APS with a limit on the number of filters. More specifically, it is recommended to add the following constraints:

[0473] The total number of adaptive loop filter categories for the luminance component, the total number of alternative filters for the chrominance component, and the total number of cross-component filters in all APS NAL units of the PU should be less than or equal to 200, 64, and 64, respectively.

[0474] 2) Based on Project 1), the encoding and decoding of APS ID in the APS syntax is further changed from u(5) to u(v), with lengths of 9, 2 and 3 respectively, which are used for ALF, LMCS and scaling list APS respectively.

[0475] 3) Building upon Project 1), further change the encoding and decoding of the ALF APS index and the number of ALF APS in PH and SH from u(v) to ue(v).

[0476] 7.3.2.5 Adaptive Parameter Set (RBSP) Syntax

[0477]

[0478] 7.3.2.7 Image Header Structure Syntax

[0479]

[0480]

[0481] 7.3.7.1 General Strip Header Syntax

[0482]

[0483]

[0484] 7.4.3.5 Adaptive Parameter Set Semantics

[0485] Each APS RBSP should be available for the decoding process before being referenced, either in at least one AU whose TemporalId is less than or equal to the TemporalId of the NAL unit of the stripe being encoded or decoded, or provided by external means.

[0486] All APS NAL cells within the PU that have specific values ​​for adaptation_parameter_set_id and aps_params_type, regardless of whether they are prefix APS NAL cells or suffix APS NAL cells, should have the same content.

[0487] The `adaptation_parameter_set_id` provides an identifier for the APS (Adaptation Parameter Set), which is then referenced by other syntax elements. The length (in bits) of the syntax element `adaptation_parameter_set_id` is: `aps_params_type = ALF_APS? 9 :(aps_params_type == LMCS_APS? 2 :3)`.

[0488] When aps_params_type equals ALF_APS[[or SCALING_APS]], the value of adaptation_parameter_set_id should be between 0 and [[7]]. Within the range of (including endpoints).

[0489] When aps_params_type equals LMCS_APS, the value of adaptation_parameter_set_id should be in the range of 0 to 3 (inclusive).

[0490] Let apsLayerId be the value of nuh_layer_id for a specific APS NAL cell, and vclLayerId be the value of nuh_layer_id for a specific VCL NAL cell. A specific VCL NAL cell should not reference a specific APS NAL cell unless apsLayerId is less than or equal to vclLayerId, and the layer whose nuh_layer_id is equal to apsLayerId is contained in at least one OLS containing a layer whose nuh_layer_id is equal to vclLayerId.

[0491] aps_params_type specifies the type of APS parameters carried in APS, as specified in Table 6.

[0492] …

[0493]

[0494] All APS NAL cells with a specific value of aps_params_type share the same value space for adaptation_parameter_set_id, regardless of the nuh_layer_id value. APS NAL cells with different values ​​of aps_params_type use a separate value space for adaptation_parameter_set_id.

[0495] 7.4.3.7 Image header structure and semantics

[0496] ph_num_alf_aps_ids_luma specifies the number of ALF APSs associated with the PH band reference.

[0497] ph_alf_aps_id_luma[i] specifies the adaptation_parameter_set_id of the i-th ALFAPS referenced by the luminance component of the strip associated with PH.

[0498] The ph_alf_aps_id_chroma specification defines the adaptation_parameter_set_id of the ALF APS referenced by the chromaticity components of the bands associated with PH.

[0499] ph_cc_alf_cb_aps_id specifies the adaptation_parameter_set_id of the ALF APS referenced by the Cb color component of the band associated with PH.

[0500] ph_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id of the ALF APS referenced by the Cr color component of the band associated with PH.

[0501] 7.4.8.1 General Strip Header Semantics

[0502] `slice_num_alf_aps_ids_luma` specifies the number of ALF APS referenced by the slice. When `slice_alf_enabled_flag` is equal to 1 and `slice_num_alf_aps_ids_luma` does not exist, the value of `slice_num_alf_aps_ids_luma` is inferred to be equal to the value of `ph_num_alf_aps_ids_luma`.

[0503] `slice_alf_aps_id_luma[i]` specifies the `adaptation_parameter_set_id` of the i-th ALF APS referenced by the luminance component of the slice. The `temporalId` of the APS NAL unit where `aps_params_type` equals `ALF_APS` and `adaptation_parameter_set_id` equals `slice_alf_aps_id_luma[i]` should be less than or equal to the `temporalId` of the NAL unit of the codec slice. When `slice_alf_enabled_flag` equals 1 and `slice_alf_aps_id_luma[i]` does not exist, the value of `slice_alf_aps_id_luma[i]` is inferred to be equal to the value of `ph_alf_aps_id_luma[i]`.

[0504]

[0505] `slice_alf_aps_id_chroma` specifies the `adaptation_parameter_set_id` of the ALF APS referenced by the chroma components of the slice. The `temporalId` of the APS NAL unit where `aps_params_type` equals `ALF_APS` and `adaptation_parameter_set_id` equals `slice_alf_aps_id_chroma` should be less than or equal to the `temporalId` of the NAL unit of the codec slice. When `slice_alf_enabled_flag` equals 1 and `slice_alf_aps_id_chroma` does not exist, the value of `slice_alf_aps_id_chroma` is inferred to be equal to the value of `ph_alf_aps_id_chroma`.

[0506]

[0507] slice_cc_alf_cb_aps_id specifies the adaptation_parameter_set_id referenced by the Cb color component of the stripe.

[0508] The TemporalId of the APS NAL unit whose aps_params_type equals ALF_APS and whose adaptation_parameter_set_id equals slice_cc_alf_cb_aps_id should be less than or equal to the TemporalId of the codec slice NAL unit. When slice_cc_alf_cb_enabled_flag equals 1 and slice_cc_alf_cb_aps_id does not exist, the value of slice_cc_alf_cb_aps_id is inferred to be equal to the value of ph_cc_alf_cb_aps_id.

[0509]

[0510] The value of alf_cc_cb_filter_signal_flag for the APS NAL cell whose aps_params_type is equal to ALF_APS and whose adaptation_parameter_set_id is equal to slice_cc_alf_cb_aps_id should be equal to 1.

[0511] `slice_cc_alf_cr_aps_id` specifies the `adaptation_parameter_set_id` referenced by the Cr color component of the slice. The `TemporalId` of the APS NAL unit where `aps_params_type` equals `ALF_APS` and `adaptation_parameter_set_id` equals `slice_cc_alf_cr_aps_id` should be less than or equal to the `TemporalId` of the NAL unit of the codec slice. When `slice_cc_alf_cr_enabled_flag` equals 1 and `slice_cc_alf_cr_aps_id` does not exist, the value of `slice_cc_alf_cr_aps_id` is inferred to be equal to the value of `ph_cc_alf_cr_aps_id`.

[0512]

[0513] The value of alf_cc_cr_filter_signal_flag for an APS NAL cell whose aps_params_type is equal to ALF_APS and whose adaptation_parameter_set_id is equal to slice_cc_alf_cr_aps_id should be equal to 1.

[0514] In the example above, the following can be used instead:

[0515] The `adaptation_parameter_set_id` provides an identifier for the APS for reference by other syntax elements. The length (in bits) of the syntax element `adaptation_parameter_set_id` is `aps_params_type = ALF_APS? M : (aps_params_type == LMCS_APS? 2 : 3)`, where M is equal to a value not less than 3 (e.g., 4, 5, 6, 7, 8, 9).

[0516] The values ​​“200, 64, 64” can be replaced with other non-zero integer values.

[0517] The value of “327” can be replaced with other non-zero integer values.

[0518] Figure 5 This is a block diagram of an example video processing system 1900 that can implement the various techniques disclosed herein. Various implementations may include some or all of the components in system 1900. System 1900 may include an input 1902 for receiving video content. The video content may be received in a raw or uncompressed format (e.g., 8 or 10-bit multi-component pixel values), or in a compressed or encoded format. Input 1902 may represent a network interface, a peripheral bus interface, or a storage interface. Examples of network interfaces include wired interfaces (such as Ethernet, Passive Optical Networking (PON), etc.) and wireless interfaces (such as Wi-Fi or cellular interfaces).

[0519] System 1900 may include a codec component 1904 capable of implementing the various codec or encoding methods described in this document. Codec component 1904 can reduce the average bit rate of the video from input 1902 to the output of codec component 1904 to produce a codec representation of the video. Therefore, codec techniques are sometimes referred to as video compression or video transcoding techniques. The output of codec component 1904 can be stored or transmitted via connected communication, as represented by component 1906. The stored or communicated bitstream (or codec) representation of the video received at input 1902 can be used by component 3108 to generate pixel values ​​or displayable video that are sent to display interface 1910. The process of generating user-visible video from the bitstream representation is sometimes referred to as video decompression. Furthermore, although some video processing operations are referred to as "codec" operations or tools, it should be understood that the codec tool or operation is used at the encoder, and the corresponding decoding tool or operation will be inverted by the decoder to retrieve the result of the codec.

[0520] Examples of peripheral bus interfaces or display interfaces may include Universal Serial Bus (USB), High Definition Multimedia Interface (HDMI), or DisplayPort. Examples of storage interfaces include SATA (Serial Advanced Technology Accessory), PCI, IDE, etc. The technologies described in this document can be implemented in a variety of electronic devices, such as mobile phones, laptops, smartphones, or other devices capable of digital data processing and / or video display.

[0521] Figure 6 This is a block diagram of a video processing apparatus 3600. Apparatus 3600 can be used to implement one or more of the methods described herein. Apparatus 3600 can be implemented 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) 3602 can be configured to implement one or more methods described herein. The memories(multiple) 3604 can be used to store data and code used to implement the methods and techniques described herein. The video processing hardware 3606 can be used to implement some of the techniques described herein in hardware circuitry.

[0522] Figure 8 This is a block diagram illustrating an example video codec system 100 that can utilize the techniques disclosed herein.

[0523] 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, which 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 destination device 120 may be referred to as a video decoding device.

[0524] The source device 110 may include a video source 112, a video encoder 114, and an input / output (I / O) interface 116.

[0525] 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 that generate video data, or combinations of these sources. Video data may include one or more pictures. Video encoder 114 encodes the video data from video source 112 to generate a bitstream. The bitstream may include a sequence of bits forming a codec representation of the video data. The bitstream may include codec pictures and associated data. A codec picture is a codec representation of a picture. Associated data may include sequence parameter sets, picture parameter sets, and other syntax elements. I / O interface 116 includes 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 medium / server 130b for access by destination device 120.

[0526] Destination device 120 may include I / O interface 126, video decoder 124 and display device 122.

[0527] 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 may be external to destination device 120 configured to connect to an external display device.

[0528] The video encoder 114 and the video decoder 124 can operate according to video compression standards such as High Efficiency Video Codec (HEVC), Multi-Functional Video Codec (VVC), and other current and / or other standards.

[0529] Figure 9 This is a block diagram illustrating an example of a video encoder 200, which may be... Figure 8 The video encoder 114 in the system 100 shown in the figure.

[0530] The video encoder 200 can be configured to perform any or all of the techniques 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.

[0531] The functional components of the video encoder 200 may include a segmentation unit 201, a prediction unit 202 (which may include a mode selection unit 203, a motion estimation unit 204, a motion compensation unit 205, and 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.

[0532] 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 may perform prediction in IBC mode, where at least one reference picture is the picture in which the current video block is located.

[0533] Furthermore, some components, such as the motion estimation unit 204 and the motion compensation unit 205, can be highly integrated, but for interpretive purposes... Figure 9 The examples are shown separately.

[0534] 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.

[0535] The mode selection unit 203 can, for example, select one of the intra-frame or inter-frame codec modes based on the error result, and provide the obtained intra-frame or inter-frame codec block to the residual generation unit 207 to generate residual block data and to the reconstruction unit 212 to reconstruct the codec block for use as a reference picture. In some examples, the mode selection unit 203 can select a combined intra-frame and inter-frame prediction (CIIP) mode, where the prediction is based on the inter-frame prediction signal and the intra-frame prediction signal. The mode selection unit 203 can also select the resolution of the motion vector (e.g., sub-pixel or full-pixel accuracy) for the block in the inter-frame prediction case.

[0536] To perform inter-frame prediction for 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 the motion information of the image from buffer 213 (rather than the image associated with the current video block) and decoded samples.

[0537] The motion estimation unit 204 and the motion compensation unit 205 can perform different operations on the current video block, for example, the different operations performed depend on whether the current video block is in an I-strip, a P-strip, or a B-strip.

[0538] In some examples, motion estimation unit 204 can perform unidirectional prediction of 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 that the reference image in list 0 or list 1 contains 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.

[0539] In other examples, motion estimation unit 204 can perform bidirectional prediction of the current video block. Motion estimation unit 204 can search for a reference video block for the current video block in the reference images of list 0 and can also search for another reference video block for the current video block in the reference images of list 1. Motion estimation unit 204 can then generate a reference index indicating that the reference images in list 0 or list 1 contain the reference video block, and a motion vector indicating the spatial displacement between the reference video block and the current video block. Motion estimation unit 204 can output the reference index and the motion vector of the current video block as the motion information of the current video block. Motion compensation unit 205 can generate a predicted video block for the current video block based on the reference video block indicated by the motion information of the current video block.

[0540] In some examples, the motion estimation unit 204 can output the complete set of motion information for the decoder's decoding process.

[0541] In some examples, motion estimation unit 204 may not output the complete set of motion information for the current video. Instead, motion estimation unit 204 may signal the motion information of the current video block by referencing the motion information of another video block. For example, motion estimation unit 204 may determine that the motion information of the current video block is sufficiently similar to the motion information of neighboring video blocks.

[0542] In one example, the motion estimation unit 204 may indicate in the syntax structure associated with the current video block that the current video block has the same motion information value as another video block.

[0543] In another example, motion estimation unit 204 can identify another video block and motion vector difference (MVD) in the syntax structure associated with the current video block. The motion vector difference indicates the difference between the motion vector of the current video block and the motion vector of the indicating video block. Video decoder 300 can use the motion vector of the indicating video block and the motion vector difference to determine the motion vector of the current video block.

[0544] As discussed above, the video encoder 200 can predictively signal motion vectors. Two examples of predictive signaling notification techniques that can be implemented by the video encoder 200 include Advanced Motion Vector Prediction (AMVP) and merge pattern signaling notification.

[0545] 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 can include the predicted video block and various syntax elements.

[0546] The residual generation unit 207 can generate residual data for the current video block by subtracting (e.g., indicated by a minus sign) multiple predicted video blocks from the current video block. The residual data for the current video block can include residual video blocks corresponding to different sample components of the samples in the current video block.

[0547] In other examples, such as in skip mode, residual data for the current video block may not exist, and the residual generation unit 207 may not perform a subtraction operation.

[0548] 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.

[0549] 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.

[0550] The inverse quantization unit 210 and the 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. The reconstruction unit 212 can add the reconstructed residual video block to the corresponding samples of one or more predicted video blocks generated by the prediction unit 202 to produce a reconstructed video block associated with the current block for storage in the buffer 213.

[0551] After the video block is reconstructed in reconstruction unit 212, a loop filtering operation can be performed to reduce video block artifacts in the video block.

[0552] Entropy encoding unit 214 can receive data from other functional components of video encoder 200. When entropy encoding unit 214 receives data, it can perform one or more entropy encoding operations to generate entropy encoded data and output a bitstream including the entropy encoded data.

[0553] Figure 10 This is a block diagram illustrating an example of a video decoder 300, which may be... Figure 8 The video decoder 114 in the system 100 shown in the figure.

[0554] The video decoder 300 can be configured to perform any or all of the techniques 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.

[0555] exist Figure 10 In the example, the video decoder 300 includes an entropy decoding unit 301, a motion compensation unit 302, an intra-frame prediction unit 303, an inverse quantization unit 304, an inverse transform unit 305, a reconstruction unit 306, and a buffer 307. In some examples, the video decoder 300 can perform operations related to the video encoder 200 ( Figure 9 The decoding process is the overall inversion of the encoding process described.

[0556] Entropy decoding unit 301 can retrieve the encoded bitstream. The encoded bitstream may include entropy-encoded video data (e.g., encoded blocks of video data). Entropy decoding unit 301 can decode the entropy-encoded video, and based on the entropy-encoded 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 such information, for example, by performing AMVP and merge modes.

[0557] The motion compensation unit 302 can generate motion compensation blocks, possibly based on interpolation filters. The identifier of the interpolation filter to be used at sub-pixel precision can be included in the syntax element.

[0558] The motion compensation unit 302 can use the interpolation filter used by the video encoder 200 during the encoding of the video block to calculate the interpolation values ​​of a sub-integer number of 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.

[0559] The motion compensation unit 302 can use some syntax information to determine: the size of the blocks used to encode (multiple) frames and / or (multiple) stripes of the encoded video sequence, segmentation information describing how each macroblock of the image of the encoded video sequence is segmented, the mode indicating how each segment is encoded, one or more reference frames (and a list of reference frames) for each inter-frame codec block, and other information for decoding the encoded video sequence.

[0560] 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.

[0561] The reconstruction unit 306 can sum the residual blocks using the corresponding prediction blocks generated by the motion compensation unit 202 or the intra-frame prediction unit 303 to form a decoded block. As desired, a deblocking filter can also be applied to filter the decoded block to remove blocking 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 produces the decoded video for presentation on the display device.

[0562] The following provides a list of preferred solutions for some embodiments.

[0563] The following solutions show example implementations of the techniques discussed in the previous chapter (e.g., Project 1).

[0564] 1. A video processing method (e.g., Figure 7 The method 700 shown includes: performing (702) a conversion between videos comprising one or more video pictures, wherein the encoding / decoding representation conforms to a format rule; wherein the format rule specifies that two or more syntax fields in a sequence parameter set control the reference picture resolution (RPR) variation in the video.

[0565] 2. The method as described in Solution 1, wherein a first syntax field of two or more syntax fields indicates whether RPR is used for one or more images, and a second syntax field of two or more syntax fields indicates whether changing the image resolution is permitted in the sequence-level codec representation.

[0566] The following solutions show example implementations of the techniques discussed in the previous chapter (e.g., Project 2).

[0567] 3. A video processing method, comprising: performing a conversion between videos including one or more video images, wherein the encoding / decoding representation conforms to a format rule; wherein the format rule specifies that a single syntax field in a sequence parameter set controls the reference image resolution (RPR) variation in the video; and wherein the format rule specifies that resampling of the inter-frame layer reference image is permitted for use in the conversion, regardless of the value of the single syntax field.

[0568] The following solutions show example implementations of the techniques discussed in the previous chapter (e.g., items 3, 5, 6, 7, 9, 10).

[0569] 4. A video processing method, comprising: performing a conversion between videos comprising one or more layers, the one or more layers comprising one or more video images, the one or more video images comprising one or more sub-images, wherein the encoding / decoding representation conforms to a format rule; wherein the format rule specifies a first constraint on cross-layer alignment or a second constraint on a combination of scalability of sub-images and inter-frame layer images.

[0570] 5. The method described in Solution 4, wherein the first constraint defines cross-layer alignment constraints on the current layer and all higher layers that depend on the current layer, but does not impose alignment constraints on lower layers of the current layer and all higher layers that do not depend on the current layer.

[0571] 6. The method described in Solution 4, wherein the second constraint imposes cross-layer alignment restrictions on all layers in each dependency tree of a particular layer.

[0572] 7. The method as described in Scheme 4, wherein the second constraint limits the value of subpic_treatment_as_pic_flag[i] based on the cross-layer alignment constraint.

[0573] 8. The method described in Solution 4, wherein the second constraint limits the value of loop_filter_across_subpic_enabled_flag[i] according to the cross-layer alignment constraint.

[0574] 9. The method of any one of solutions 4 to 8, wherein the first constraint and / or the second constraint are specified for the target group access unit.

[0575] 10. The method as described in Solution 4, wherein the second constraint limits the value of each of the scaling window parameters scaling_win_left_offset, scaling_win_right_offset, scaling_win_top_offset, and scaling_win_bottom_offset according to the cross-layer alignment constraint.

[0576] The following solutions show example implementations of the techniques discussed in the previous chapter (e.g., Project 11).

[0577] 11. A video processing method, comprising: performing a conversion between videos comprising one or more layers, the one or more layers comprising one or more video images, the one or more video images comprising one or more sub-images, wherein the conversion conforms to a format rule that specifies that an inter-frame layer reference image or a long-term reference image is not permitted as a juxtaposed image of the current image used for the conversion.

[0578] The following solutions show example implementations of the techniques discussed in the previous chapter (e.g., Item 12).

[0579] 12. A video processing method, comprising: performing a conversion between a video comprising multiple images and a codec representation of the video, wherein the conversion conforms to a rule that specifies that for any two images within a codec video sequence of the same codec layer or a codec video sequence having the same values ​​of pic_width_in_luma_samples and pic_height_in_luma_samples, the values ​​of each of scaling_win_left_offset, scaling_win_right_offset, scaling_win_top_offset, and scaling_win_bottom_offset are the same.

[0580] The following solutions show example implementations of the techniques discussed in the previous chapter (e.g., Item 13).

[0581] 13. A video processing method, comprising: performing a conversion between a video comprising multiple images and a codec representation of the video, wherein the conversion conforms to a rule that specifies that inter-frame layer prediction is allowed only if the current image is an intra-frame random access point image, provided that the image resolution or scaling window differs for the current image and other images in the same access unit.

[0582] 14. The method of any one of solutions 1 to 13, wherein the conversion includes encoding the video into a codec representation.

[0583] 15. The method of any one of solutions 1 to 13, wherein the conversion includes decoding the codec representation to generate pixel values ​​of the video.

[0584] 16. A video decoding apparatus, comprising a processor configured to implement the method described in one or more of solutions 1 to 15.

[0585] 17. A video encoding / decoding apparatus, comprising a processor configured to implement the method described in one or more of solutions 1 to 15.

[0586] 18. A computer program product having computer code stored thereon, which, when executed by a processor, causes the processor to implement the method described in any one of solutions 1 to 15.

[0587] 19. A method, apparatus or system described in this document.

[0588] Figure 13 This is a flowchart representation of a method 1300 for video processing according to the present technology. Method 1300 includes, in operation 1310, performing a conversion between a video image and a video bitstream according to rules. The rules specify that at least one of the scaling window offsets applicable to the video image is allowed to be negative.

[0589] In some embodiments, the scaling window offset includes at least one of a right scaling window offset, a left scaling window offset, a top scaling window offset, or a bottom scaling window offset. In some embodiments, at least one of the scaling window offsets is not less than an integer X, where X is a negative number. In some embodiments, at least one of the scaling window offsets is greater than an integer X, where X is a negative number. In some embodiments, X is based on the size of the video image.

[0590] In some embodiments, at least one of the scaling window offsets is associated with the size of the video image. In some embodiments, the size of the video image includes the image width or the image height in luminance samples.

[0591] In some embodiments, the output image is determined based on a scaled video image. A first variable defining the width of the output image is equal to the width of the video image in luminance samples minus the weighted sum of the right and left offsets of the scaling window. In some embodiments, a second variable defining the height of the output image is equal to the height of the video image in luminance samples minus the weighted sum of the top and bottom offsets of the scaling window. In some embodiments, the rule further specifies that the first and second variables satisfy constraints. In some embodiments, the first variable is represented as WidthL, and the constraint specifies that X*WidthL is greater than or equal to a first integer and less than or equal to a second integer, where X is an integer. In some embodiments, the second variable is represented as HeightL, and the constraint specifies that Y*WidthL is greater than or equal to a third integer and less than or equal to a fourth integer, where Y is an integer. In some embodiments, the first or third integer is represented as A*(BC), where A, B, and C are integers.

[0592] In some embodiments, at least one of the scaling window offsets indicates a scaling ratio used to resample a reference image of the video image. In some embodiments, at least one of the scaling window offsets is encoded and decoded using signed binarization.

[0593] In some embodiments, the rule specifies a constraint between at least one scaling window offset and the size of the video image based on whether at least one of the scaling window offsets is negative. In some embodiments, the constraint is specified based on whether at least one of the left window offset and / or right window offset is negative. In some embodiments, the constraint is specified based on whether at least one of the top window offset and / or bottom window offset is negative. In some embodiments, the constraint between at least one scaling window offset and the size of the video image is specified only if at least one of the scaling window offsets is zero. In some embodiments, if at least one of the left or right window offsets is not negative, the weighted sum of the left and right window offsets is less than the width of the video image in the luminance sample. In some embodiments, if at least one of the top or bottom window offsets is not negative, the weighted sum of the top and bottom window offsets is less than the height of the video image in the luminance sample.

[0594] In some embodiments, the constraints are defined based on the absolute value of at least one of the scaling window offsets. In some embodiments, the weighted sum of the absolute values ​​of the left and right window offsets is less than X1 multiplied by the width of the video image in the luminance sample, where X1 is a positive integer greater than or equal to 1. In some embodiments, the weighted sum of the absolute values ​​of the top and bottom window offsets is less than X2 multiplied by the height of the video image in the luminance sample, where X2 is a positive integer greater than or equal to 1.

[0595] In some embodiments, the rule specifies that the constraint does not apply if any of the scaling window offsets is negative. In some embodiments, the rule specifies that the size of the video image or the size of the reference image of the video image is based on whether the scaling window offset is negative. In some embodiments, the size of the output image of the video image is determined based on whether at least one of the scaling window offsets is negative. In some embodiments, if the scaling window offset of the reference image is negative, the size of the output image is determined by treating the scaling window offset as zero.

[0596] In some embodiments, the rule specifies that fractional sample interpolation is performed based on whether at least one of the scaling window offsets is negative. In some embodiments, when the scaling window offset of the reference image is negative, motion compensation is performed for the transformation by treating the scaling window offset as zero. In some embodiments, when the scaling window offset of the video image is negative, fractional sample interpolation is performed for the transformation by treating the scaling window offset as zero.

[0597] Figure 14 This is a flowchart representation of a method 1400 for video processing according to the present technology. Method 1400 includes, in operation 1410, performing a conversion between video blocks and a video bitstream according to rules. The rules specify whether transform skipping is enabled at the video unit level, the presence of a syntax flag in the residual codec at the video unit level, and the value of a first syntax element indicating the use of symbolic data hiding in the video unit and a second syntax element indicating the use of associated quantization in the video unit.

[0598] In some embodiments, the video unit level includes the stripe level. In some embodiments, the syntax flag is indicated in the stripe header as ts_residual_coding_disabled_flag. In some embodiments, the syntax flag is present in the bitstream based on a third syntax element in the sequence parameter set indicating whether transform skipping is enabled at the sequence level, and wherein the syntax flag is present if: (1) the value of the third syntax element specifies that transform skipping is enabled at the sequence level, (2) the value of the second syntax element specifies that correlated quantization is not used for the video unit, and (3) the value of the first syntax element specifies that symbolic data hiding is not used for the video unit. In some embodiments, the value of the third syntax element specifying that transform skipping is enabled at the sequence level is equal to 1, the value of the second syntax element specifying that correlated quantization is not used for the video unit is equal to 0, and the value of the first syntax element specifying that symbolic data hiding is not used for the video unit is equal to 0.

[0599] In some embodiments, if the first syntax element is absent, the first syntax element indicating the use of hidden symbolic data in the video unit has a default value of 0. In some embodiments, if the second syntax element is absent, the second syntax element indicating the use of correlated quantization in the video unit has a default value of 0. In some embodiments, the first syntax element is based on a fourth syntax element in the sequence parameter set indicating whether to enable symbolic data hiding at the sequence level. In some embodiments, the first syntax element is determined based on the second and fourth syntax elements. In some embodiments, the second syntax element is based on a fifth syntax element in the sequence parameter set indicating whether to enable correlated quantization at the sequence level.

[0600] In some embodiments, whether symbolic data hiding or correlated quantization is applied to the block's transformation is based on whether transform skip residual coding is enabled. In some embodiments, when transform skip residual coding is enabled, symbolic data hiding or correlated quantization is not applied to the block's transformation. In some embodiments, a syntax flag is indicated before a first syntax element or a second syntax element. In some embodiments, the presence of a first syntax element or a second syntax element is based on a syntax element indicating whether transform skip residual coding is enabled in a video unit. In some embodiments, a video unit includes a sequence, a group of pictures, or a picture. In some embodiments, transform skip residual coding is not used when symbolic data hiding or correlated quantization is applied to the transformation. In some embodiments, transform skip residual coding is a transform coefficient coding technique applied to video blocks encoded in a transform skip mode, symbolic data hiding is a technique that omits encoding and decoding the coefficient symbol flag of the last non-zero coefficient, and correlated quantization is a mode where the quantization of a sample depends on the state of the previous sample.

[0601] Figure 15 This is a flowchart representation of a method 1500 for video processing according to the present technology. Method 1500 includes, in operation 1510, performing a conversion between video and a video bitstream according to rules. The rules specify that a maximum number of syntax elements supporting sub-block-based merge motion vector prediction candidates, defined by a sequence parameter set subtracted from 5, are in the range of 0 to N (inclusive), where N is an integer equal to 5 minus the value of a syntax flag indicating whether a sub-block-based temporal motion vector predictor is enabled for the conversion. In some embodiments, the syntax elements are in the range of 0 to 4 (inclusive). In some embodiments, the syntax element is inferred to be equal to 5 if the syntax flag is absent.

[0602] In some embodiments, the conversion includes encoding video into a bitstream. In some embodiments, the conversion includes decoding video from the bitstream.

[0603] 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 uses the format rules to parse the syntax elements in the codec representation, determining the presence or absence of syntax elements according to the format rules to generate the decoded video.

[0604] In this document, 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 the pixel representation of a video to the corresponding bitstream representation, and vice versa. As defined in the syntax, the bitstream representation of the current video block can, for example, correspond to bits that are co-occurring or scattered at different positions within the bitstream. For example, a macroblock can be encoded based on the error residual values ​​of the transformation and encoding / decoding, and also using bits in the header and other fields in the bitstream. Furthermore, during the conversion, the decoder can, based on this determination, parse the bitstream knowing that some fields may or may not be present, 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.

[0605] The disclosures and other schemes, examples, embodiments, modules, and functional operations described in this document can be implemented in digital electronic circuits or in computer software, firmware, or hardware, containing the structures disclosed in this document and their equivalents, or combinations thereof. The disclosed and other embodiments can be implemented as one or more computer program products encoded on a computer-readable medium, such as one or more computer program instruction modules, for execution by a data processing apparatus or for controlling 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 complex influencing machine-readable propagating signals, or combinations thereof. The term "data processing apparatus" encompasses all means, devices, and machines for processing data, including, for example, a programmable processor, a computer, or multiple processors or computers. In addition to hardware, the apparatus may 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. Propagating signals are artificially generated signals, such as machine-generated electrical, optical, or electromagnetic signals, which are generated to encode information for transmission to a suitable receiver device.

[0606] 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 in 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 co-located files (e.g., a file storing one or more modules, subroutines, or code portions). A computer program can be deployed to execute on one computer or on multiple computers located at a single site or distributed across multiple sites and interconnected by a communications network.

[0607] The processes and logic flows described in this document can be performed by one or more programmable processors executing one or more computer programs to perform functions by manipulating input data and generating outputs. The processes and logic flows can also be performed by special-purpose logic circuitry (e.g., field-programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs)), and the apparatus can be implemented as special-purpose logic circuitry (e.g., FPGAs or ASICs).

[0608] Processors suitable for executing computer programs include, for example, both general-purpose and special-purpose microprocessors, and any one or more processors in any type 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 one or more mass storage devices (e.g., magneto-optical, magneto-optical, or optical disc) for storing data, or operatively coupled to receive data from or transfer data to a mass storage device (e.g., magneto-optical, magneto-optical, or optical disc), or both. However, a computer does not necessarily 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 (e.g., EPROM, EEPROM, and flash memory devices); magnetic disks (e.g., internal hard disks or removable disks); magneto-optical disks; and CD-ROM and DVD-ROM disks. Processors and memory may be supplemented by or incorporated into special-purpose logic circuitry.

[0609] While this patent document contains numerous details, these details should not be construed as limiting any subject matter or the scope of the claims, but rather as descriptions of features specific to particular embodiments of a particular art. In this patent document, certain features described 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 various suitable sub-combinations. Furthermore, although features may be described above as operating in certain combinations and even initially claimed in the same manner, in certain circumstances one or more features from the claimed combination may be removed from the combination, and the claimed combination may be for sub-combinations or variations thereof.

[0610] 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 or sequence shown, or to perform all the operations shown, in order 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.

[0611] Only a few implementations and examples are described, and other implementations, enhancements and variations can be made based on what is described and shown in this patent document.

Claims

1. A method for processing video data, comprising: Perform conversion between a video comprising one or more video units and the bitstream of that video according to the rules. The rule specifies that, based on the values ​​of a first syntax element and a second syntax element, syntax flags related to transform skip residual encoding / decoding are conditionally included in the bitstream at the video unit level, wherein the first syntax element indicates the use of symbolic data hiding at the video unit level, and the second syntax element indicates the use of related quantization at the video unit level. Wherein, the video unit in the one or more video units is a stripe, the video unit level corresponds to the stripe level, and the syntax flag is represented as ts_residual_coding_disabled_flag in the stripe header; Whether the syntax flag is included in the bitstream is further based on a third syntax element in the sequence parameter set, which indicates whether transform skipping is allowed at the sequence level. The syntax flags are present when: the value of the third syntax element specifies that the transform is allowed to be skipped at the sequence level; the value of the second syntax element specifies that the correlated quantization is not used for the video unit; and the value of the first syntax element specifies that the symbolic data hiding is not used for the video unit.

2. The method according to claim 1, wherein, The third syntax element is represented as `sps_transform_skip_enabled_flag` in the sequence parameter set. Specifically, the value of the third syntax element that allows the transform to be skipped at the sequence level is specified to be equal to 1; the value of the second syntax element for which the correlated quantization is not used in the video unit is specified to be equal to 0; and the value of the first syntax element for which the symbolic data hiding is not used in the video unit is specified to be equal to 0. Wherein, in the absence of the first syntax element, the first syntax element used to indicate the hiding of symbolic data in the video unit has a default value of 0, and Wherein, if the second syntax element is not present, the second syntax element indicating the use of the relevant quantization in the video unit has a default value of 0.

3. The method according to claim 1, wherein, Based on the fourth syntax element in the sequence parameter set, the second syntax element is conditionally included in the bitstream, and the fourth syntax element in the sequence parameter set indicates whether the associated quantization is enabled at the sequence level.

4. The method according to claim 3, wherein, Based on the fifth syntax element and the second syntax element in the sequence parameter set, the first syntax element is conditionally included in the bitstream, and the fifth syntax element in the sequence parameter set indicates whether the symbolic data hiding is enabled at the sequence level.

5. The method according to claim 1, wherein, When the transform skip residual encoding / decoding is enabled, the symbol data hiding and the correlated quantization are not applicable to the video unit.

6. The method according to claim 1, wherein, The transform skip residual encoding and decoding is a transform coefficient encoding and decoding technique applied to video blocks encoded and decoded in transform skip mode. The symbolic data hiding mentioned above is a technique that omits the encoding and decoding of coefficient symbol flags, or The relevant quantization is a pattern in which the quantization of a sample depends on the state of the previous sample.

7. The method according to claim 1, wherein, The video includes video images, and The rule further specifies that at least one scaling window offset applicable to the scaling window offset of the video image is not less than X, where X is a negative integer value determined based on the size of the video image. The scaling window offset includes at least one of the following: scaling window right offset, scaling window left offset, scaling window top offset, or scaling window bottom offset. The dimensions of the video image include the image width expressed in luminance samples or the image height expressed in luminance samples.

8. The method according to claim 7, wherein, SubWidthC The value of (scaling_win_left_offset + scaling_win_right_offset) is less than the image width expressed in luminance samples, and SubHeightC The value of (scaling_win_top_offset + scaling_win_bottom_offset) is less than the image height represented by luminance samples, where scaling_win_left_offset represents the left offset of the scaling window, scaling_win_right_offset represents the right offset of the scaling window, scaling_win_top_offset represents the top offset of the scaling window, and scaling_win_bottom_offset represents the bottom offset of the scaling window. SubWidthC and SubHeightC are determined based on the chroma format of the video image.

9. The method according to claim 1, wherein, The rule stipulates that the type of the adaptive parameter set should be indicated before the identifier of the adaptive parameter set.

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

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

12. An apparatus for processing video data, comprising a processor and a non-transitory memory having instructions thereon, wherein the instructions, when executed by the processor, cause the processor to: Perform conversion between a video comprising one or more video units and the bitstream of that video according to the rules. in, The rule specifies that, based on the values ​​of a first syntax element and a second syntax element, syntax flags related to transform skip residual encoding / decoding will be conditionally included in the bitstream at the video unit level, wherein the first syntax element indicates the use of symbolic data hiding at the video unit level, and the second syntax element indicates the use of related quantization at the video unit level. Wherein, the video unit in the one or more video units is a stripe, the video unit level corresponds to the stripe level, and the syntax flag is represented as ts_residual_coding_disabled_flag in the stripe header; Whether the syntax flag is included in the bitstream is further based on a third syntax element in the sequence parameter set, which indicates whether transform skipping is allowed at the sequence level. The syntax flags are present when: the value of the third syntax element specifies that the transform is allowed to be skipped at the sequence level; the value of the second syntax element specifies that the correlated quantization is not used for the video unit; and the value of the first syntax element specifies that the symbolic data hiding is not used for the video unit.

13. The apparatus according to claim 12, wherein, The third syntax element is represented as `sps_transform_skip_enabled_flag` in the sequence parameter set. Specifically, the value of the third syntax element that allows the transform to be skipped at the sequence level is specified to be equal to 1; the value of the second syntax element for which the correlated quantization is not used in the video unit is specified to be equal to 0; and the value of the first syntax element for which the symbolic data hiding is not used in the video unit is specified to be equal to 0. Wherein, in the absence of the first syntax element, the first syntax element used to indicate the hiding of symbolic data in the video unit has a default value of 0, and Wherein, if the second syntax element is not present, the second syntax element indicating the use of the relevant quantization in the video unit has a default value of 0.

14. The apparatus according to claim 12, wherein, Based on the fourth syntax element in the sequence parameter set, the second syntax element is conditionally included in the bitstream, and the fourth syntax element in the sequence parameter set indicates whether the relevant quantization is enabled at the sequence level; Specifically, based on the fifth syntax element and the second syntax element in the sequence parameter set, the first syntax element is conditionally included in the bitstream, and the fifth syntax element in the sequence parameter set indicates whether the symbolic data hiding is enabled at the sequence level.

15. The apparatus according to claim 12, wherein, When the transform skip residual encoding / decoding is enabled, the symbol data hiding and the correlated quantization are not applicable to the video unit; The transform skip residual encoding / decoding is a transform coefficient encoding / decoding technique applied to video blocks encoded / decoded in transform skip mode. The symbolic data hiding mentioned above is a technique that omits the encoding and decoding of coefficient symbol flags, or The relevant quantization is a pattern in which the quantization of a sample depends on the state of the previous sample.

16. A non-transitory computer-readable storage medium for storing instructions, said instructions causing a processor to: Perform conversion between a video comprising one or more video units and the bitstream of that video according to the rules. in, The rule specifies that, based on the values ​​of a first syntax element and a second syntax element, syntax flags related to transform skip residual encoding / decoding will be conditionally included in the bitstream at the video unit level, wherein the first syntax element indicates the use of symbolic data hiding at the video unit level, and the second syntax element indicates the use of related quantization at the video unit level. Wherein, the video unit in the one or more video units is a stripe, the video unit level corresponds to the stripe level, and the syntax flag is represented as ts_residual_coding_disabled_flag in the stripe header; Whether the syntax flag is included in the bitstream is further based on a third syntax element in the sequence parameter set, which indicates whether transform skipping is allowed at the sequence level. The syntax flags are present when: the value of the third syntax element specifies that the transform is allowed to be skipped at the sequence level; the value of the second syntax element specifies that the correlated quantization is not used for the video unit; and the value of the first syntax element specifies that the symbolic data hiding is not used for the video unit.

17. A non-transitory computer-readable recording medium storing a bitstream of video, wherein a computer program is also stored thereon, When the computer program is executed by a processor, it generates the bit stream as described in claim 1.

18. A method for storing a bitstream of video, comprising: The bitstream is generated for a video comprising one or more video units according to the rules; The bitstream is stored in a non-transitory computer-readable recording medium. in, The rule specifies that, based on the values ​​of a first syntax element and a second syntax element, syntax flags related to transform skip residual encoding / decoding will be conditionally included in the bitstream at the video unit level, wherein the first syntax element indicates the use of symbolic data hiding at the video unit level, and the second syntax element indicates the use of related quantization at the video unit level. Wherein, the video unit in the one or more video units is a stripe, the video unit level corresponds to the stripe level, and the syntax flag is represented as ts_residual_coding_disabled_flag in the stripe header; Whether the syntax flag is included in the bitstream is further based on a third syntax element in the sequence parameter set, which indicates whether transform skipping is allowed at the sequence level. The syntax flags are present when: the value of the third syntax element specifies that the transform is allowed to be skipped at the sequence level; the value of the second syntax element specifies that the correlated quantization is not used for the video unit; and the value of the first syntax element specifies that the symbolic data hiding is not used for the video unit.

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