Prediction refinement for affine MERGE and affine motion vector prediction modes

Abstract

Methods and apparatus for video processing are disclosed. The processing may include video encoding, video decoding, or video transcoding. An example method includes: for conversion between a video block of a video and a bitstream of the video, determining a size of a prediction block corresponding to the video block according to a rule; and performing the conversion based on the determination, wherein the rule stipulates that a first size of the prediction block is determined in response to whether a prediction refinement technique using optical flow is used to encode and decode the video block, and wherein the video block has a second size and is encoded and decoded using an affine merge mode or an affine advanced motion vector prediction mode.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is to timely claim the priority and benefits of International Patent Application No. PCT / CN2020 / 080602 filed on March 23, 2020. The entire disclosure of the above application is incorporated by reference as part of the disclosure of this application. Technical Field

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

[0004] Digital video accounts for the largest use of bandwidth on the Internet and other digital communications networks. Bandwidth demand for digital video usage is expected to continue to grow as the number of connected user devices capable of receiving and displaying video increases. Summary of the invention

[0005] This document discloses techniques that can be used by video encoders and decoders for processing a codec representation of a 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 conversion between a video including a picture including one or more slices and a bitstream of the video, wherein the conversion complies with a rule that specifies whether a deblocking filter is applied to one or more slices of a reference picture parameter set based on at least a first syntax element included in the picture parameter set, and wherein the first syntax element indicates whether the deblocking filter is disabled for the picture.

[0007] In another example aspect, a video processing method is disclosed. The method includes performing conversion between a video including a picture including one or more slices and a bitstream of the video,

[0008] Among other things, the conversion complies with a rule that specifies whether a deblocking filter is applied to one or more slices of a reference picture parameter set based solely on a syntax element included in the picture parameter set that indicates whether the deblocking filter is disabled.

[0009] In another example aspect, a video processing method is disclosed. The method performs conversion between a video including one or more pictures and a bitstream of the video, the one or more pictures including one or more slices, wherein the bitstream complies with a rule, wherein the rule provides for determining whether to override deblocking of the slice or the picture at a slice level or at a picture level based on a first value of a first syntax element at a slice level or a second value of a second syntax element at a picture level, and wherein the rule provides for determining a first value of the first syntax element independently of a second value of a second syntax element at a picture level in response to the first syntax element not being present in a slice header.

[0010] In another example aspect, a video processing method is disclosed. The method performs conversion between a video including one or more pictures and a bitstream of the video, the one or more pictures including one or more slices, wherein the bitstream complies with a rule, wherein the rule provides for determining whether a deblocking parameter is included in a slice header or a picture header based on a first value of a first syntax element at a slice level or a second value of a second syntax element at a picture level, and wherein the rule provides for determining a first value of the first syntax element independently of a second value of a second syntax element at a picture level in response to the first syntax element not being present in the slice header.

[0011] In another example aspect, a video processing method is disclosed. The method performs conversion between a video including one or more pictures and a bitstream of the video, the one or more pictures including one or more slices, wherein the bitstream conforms to a format rule, the format rule dictating whether a first syntax element and a second syntax element are included in a picture header and a slice header, respectively, or whether the first syntax element and the second syntax element are inferred based on a value of a third syntax element in a picture parameter set, wherein the first syntax element indicates whether a deblocking filter is disabled at a picture level of the video, wherein the second syntax element indicates whether a deblocking filter is disabled at a slice level of the video, and wherein the third syntax element indicates whether a deblocking filter is enabled for one or more pictures of a reference picture parameter set.

[0012] In another example aspect, a video processing method is disclosed. The method performs conversion between a video including one or more pictures and a bitstream of the video, the one or more pictures including one or more slices, wherein the conversion complies with a rule, the rule dictating whether a deblocking filter is applied to a slice is based on a syntax element included in a slice header and / or a picture header and / or a picture parameter set referenced by the slice, and wherein the syntax element indicates whether the deblocking filter is enabled at a picture parameter set level and / or a slice level and / or a picture level.

[0013] In another example aspect, a video processing method is disclosed. The method performs conversion between a video including one or more pictures and a bitstream of the video, the one or more pictures including one or more slices, wherein the conversion complies with a rule that specifies whether a deblocking filter is applied to the slice is based on a syntax element included in a sequence parameter set referenced by the slice, and wherein the syntax element includes a first syntax element indicating whether the deblocking filter is enabled and / or a set of syntax elements indicating a first set of parameters for the deblocking filter.

[0014] In another example aspect, a video processing method is disclosed. A conversion between a video including one or more pictures and a bitstream of the video is performed, the one or more pictures including one or more slices, wherein the conversion complies with a rule that specifies whether a deblocking filter is applied to the slice is based on a non-binary syntax element included in a video unit level, and wherein the non-binary syntax element indicates whether and / or how a deblocking filter is applied to the one or more slices.

[0015] In another example aspect, a video processing method is disclosed. A conversion between a video including one or more pictures and a bitstream of the video is performed, the one or more pictures including one or more slices, wherein the conversion complies with a rule that specifies that: (1) a deblocking filter is enabled at a picture level of the video or a slice level of the video, and (2) a zero-valued deblocking parameter offset of β and tC is used for parameters of the deblocking filter.

[0016] In another example aspect, a video processing method is disclosed. The method includes: determining a size of a prediction block corresponding to a video block for conversion between a video block of a video and a bitstream of the video according to a rule; and performing the conversion based on the determination, wherein the rule specifies determining a first size of the prediction block in response to whether a prediction refinement technique using optical flow is used to encode and decode the video block, and wherein the video block has a second size and is encoded and decoded using an affine merge mode or an affine advanced motion vector prediction mode.

[0017] In another example aspect, a video processing method is disclosed. The method includes performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video, wherein a rule specifies indicating a first syntax element in a video level higher than a picture level or a slice level, and wherein the first syntax element indicates whether the picture level or the slice level includes a quantization parameter increment.

[0018] In another example aspect, a video processing method is disclosed. The method includes performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video, wherein a first rule specifies that a first flag in a first video level indicates whether one or more chroma quantization parameter offsets are included in the first video level, wherein the first video level is higher than the slice level, wherein a second rule specifies that a second flag in a second video level indicates whether one or more chroma quantization parameter offsets are included in a picture header or a slice header, and wherein the second video level is higher than the picture level.

[0019] In another example aspect, a video processing method is disclosed. The method includes performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video, wherein the bitstream includes a first syntax element indicating a codec block subdivision value, and wherein the codec block subdivision value has a range according to a rule.

[0020] In another example aspect, a video processing method is disclosed. The method includes performing a conversion between videos including one or more video pictures, the one or more video pictures including one or more video slices, wherein the conversion complies with a first rule that specifies that a decision regarding applicability of a deblocking filter for one or more video slices of a reference video picture parameter set is performed based on a deblocking syntax field included in a picture header of the corresponding video picture.

[0021] In another example aspect, another video processing method is disclosed. The method includes performing a conversion between videos including one or more video pictures, the one or more video pictures including one or more video slices, wherein the conversion complies with a rule that constrains applicability of a deblocking filter for a video slice based on fields included at a slice header level and / or a picture header level and / or a picture parameter set level of the video slice.

[0022] In another example aspect, another video processing method is disclosed. The method includes determining the applicability of a prediction refinement based optical flow (PROF) codec and an affine advanced motion vector prediction codec based on a first rule or an affine merge mode based on a second rule; and performing conversion between a video block of a video and a codec representation of the video based on the determination.

[0023] In another example aspect, another video processing method is disclosed. The method includes performing conversion between a video including one or more pictures including one or more slices and a codec representation of the video, wherein a first syntax element at a picture level or a slice level and / or a second syntax element at another level indicating quantization parameter increment or offset signaling is conditionally included in the codec representation according to a rule.

[0024] In another example aspect, another video processing method is disclosed. The method includes performing a conversion between a video including one or more pictures including one or more slices and a codec representation of the video, wherein the codec representation includes a syntax element indicating a codec block subdivision value (cbSubDiv), the range of the codec block subdivision value according to a rule.

[0025] In yet another example aspect, a video codec apparatus is disclosed. The video codec includes a processor configured to implement the above method.

[0026] In yet another example aspect, a video decoder apparatus is disclosed. The video decoder includes a processor configured to implement the above method.

[0027] In yet another exemplary aspect, a computer readable medium having code stored thereon is disclosed. The code is in the form of processor executable code embodying one of the methods described herein.

[0028] These and other features are described throughout this document. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a block diagram of an example video processing system.

[0030] Figure 2 A block diagram of a video processing device.

[0031] Figure 3 A flow chart of an example method for video processing.

[0032] Figure 4 is a block diagram illustrating a video encoding and decoding system according to some embodiments of the present disclosure.

[0033] Figure 5 is a block diagram illustrating an encoder according to some embodiments of the present disclosure.

[0034] Figure 6 is a block diagram illustrating a decoder according to some embodiments of the present disclosure.

[0035] Figures 7 to 19 is a flow chart of an example method of video processing. DETAILED DESCRIPTION

[0036] The section titles used in this document are for ease of understanding and do not limit the applicability of the techniques and embodiments disclosed in each section to only that section. In addition, the use of H.266 terminology in some descriptions is only for ease of understanding and is not intended to limit the scope of the disclosed technology. Therefore, the techniques described herein are also applicable to other video codec protocols and designs.

[0037] 1. Introduction

[0038] This document relates to video codec technology. Specifically, it is about supporting deblocking signaling, QP increment (delta) / offset signaling, cbSubdiv value definition for quantization groups, and PROF processing in video codecs. These ideas can be applied alone or in various combinations to any video codec standard or non-standard video codec that supports multi-layer video codecs (e.g., the Versatile Video Codec (VVC) under development).

[0039] 2. Abbreviations

[0040] APS Adaptive Parameter Set

[0041] AU Access Unit

[0042] AUD Access Unit Delimiter

[0043] AVC Advanced Video Codec

[0044] CLVS Codec Layer Video Sequence

[0045] CPB Codec Picture Buffer

[0046] CRA Clean Random Access

[0047] CTU Codec Tree Unit

[0048] CVS codec video sequence

[0049] DPB Decoded Picture Buffer

[0050] DPS Decoding Parameter Set

[0051] EOB End of bitstream

[0052] EOS sequence ends

[0053] GDR Gradual Decode Refresh

[0054] HEVC High Efficiency Video Codec

[0055] HRD Hypothesized Reference Decoder

[0056] IDR Instant Decode Refresh

[0057] JEM Joint Exploration Model

[0058] MCTS Motion Constraint Episodes

[0059] NAL Network Abstraction Layer

[0060] OLS output layer set

[0061] PH Image Header

[0062] PPS Picture Parameter Set

[0063] PROF Prediction refinement using optical flow

[0064] PTL grade, level, level

[0065] PU Picture Unit

[0066] RBSP Raw Byte Sequence Payload

[0067] SEI Supplemental Enhancement Information

[0068] SH Strip Header

[0069] SPS Sequence Parameter Set

[0070] SVC Scalable Video Codec

[0071] VCL video codec layer

[0072] VPS Video Parameter Set

[0073] VTM VVC test model

[0074] VUI Video Availability Information

[0075] VVC Multi-functional Video Codec

[0076] 3. Preliminary Discussion

[0077] Video codec standards have evolved primarily through the development of the well-known ITU-T and ISO / IEC standards. ITU-T produced the H.261 and H.263 standards, ISO / IEC produced the MPEG-1 and MPEG-4 Visual standards, and the two organizations jointly produced 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 structure, which utilizes temporal prediction plus transform codec. In order 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 simultaneously every quarter, and the goal of the new codec standard is to reduce the bit rate by 50% compared to HEVC. The new video codec standard was officially named Versatile 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 the continuous efforts of VVC standardization, new codec technologies are adopted into the VVC standard at each JVET meeting. The working draft of VVC and the test model VTM are updated after each meeting. The VVC project now aims to be technically completed (FDIS) at the meeting in July 2020.

[0078] 3.1.PPS Syntax and Semantics

[0079] In the latest VVC draft text, the GCI syntax and semantics are as follows:

[0080]

[0081]

[0082]

[0083]

[0084]

[0085] The PPS RBSP shall be available to the decoding process before being referenced, included in at least one AU with a TemporalId less than or equal to the TemporalId of the PPS NAL unit, or provided by external means.

[0086] All PPS NAL units within a PU with a specific value of pps_pic_parameter_set_id shall have the same content.

[0087] pps_pic_parameter_set_id identifies the PPS referenced by other syntax elements. The value of pps_pic_parameter_set_id shall be in the range of 0 to 63 (inclusive).

[0088] Regardless of the nuh_layer_id value, PPS NAL units share the same value space of pps_pic_parameter_set_id.

[0089] Let ppsLayerId be the value of numh_layer_id of a particular PPS NAL unit, and vclLayerId be the value of numh_layer_id of a particular VCL NAL unit. A particular VCL NAL unit shall not refer to a particular PPS NAL unit unless a layer with ppsLayerId less than or equal to vclLayerId and nuh_layer_id equal to ppsLayerId is contained in at least one OLS that includes a layer with nuh_layer_id equal to vclLayerId.

[0090] pps_seq_parameter_set_id specifies the value of sps_seq_parameter_set_id of the SPS. The value of pps_seq_parameter_set_id shall be in the range of 0 to 15 (inclusive). The value of pps_seq_parameter_set_id shall be the same in all PPSs referenced by a codec picture in CLVS.

[0091] mixed_nalu_types_in_pic_flag equal to 1 specifies that each picture of the referenced PPS has multiple VCL NAL units, the VCL NAL units do not have the same nal_unit_type value, and the picture is not an IRAP picture. mixed_nalu_types_in_pic_flag equal to 0 specifies that each picture of the referenced PPS has one or more VCL NAL units, and the VCL NAL units of each picture of the referenced PPS have the same nal_unit_type value.

[0092] When no_mixed_nalu_types_in_pic_constraint_flag is equal to 1, the value of mixed_nalu_types_in_pic_flag shall be equal to 0.

[0093] For each slice having a nal_unit_type value nalUnitTypeA in the range IDR_W_RADL to CRA_NUT (inclusive) in a picture picA that also contains one or more slices having another value of nal_unit_type (i.e., the value of mixed_nalu_types_in_pic_flag of picture picA is equal to 1), the following applies:

[0094] - The slice shall belong to the sub-picture subpicA for which the value of subpic_treated_as_pic_flag[i] is equal to 1.

[0095] - A slice shall not belong to a sub-picture of picA that contains VCL NAL units whose nal_unit_type is not equal to nalUnitTypeA.

[0096] - If nalUnitTypeA is equal to CRA, then for all subsequent PUs in the CLVS that follow the current picture in decoding order and output order, the RefPicList[0] and RefPicList[1] of the slices in subpicA in these PUs shall not include any pictures that precede picA in decoding order in the active entry.

[0097] - Otherwise (i.e., nalUnitTypeA is equal to IDR_W_RADL or IDR_N_LP), for all PUs in the CLVS that follow the current picture in decoding order, neither RefPicList[0] nor RefPicList[1] of the slices in subpicA in these PUs should include any picture that precedes picA in decoding order in the active entry.

[0098] NOTE 1 – mixed_nalu_types_in_pic_flag equal to 1 indicates that the picture referencing the PPS contains slices with different NAL unit types, for example, a codec picture originating from a sub-picture bitstream merge operation, and the encoder must ensure matching bitstream structure and further alignment of parameters of the original bitstream. An example of such alignment is as follows: When the value of sps_idr_rpl_flag is equal to 0 and mixed_nalu_types_in_pic_flag is equal to 1, the picture referencing the PPS shall not have slices with nal_unit_type equal to IDR_W_RADL or IDR_N_LP.

[0099] pic_width_in_luma_samples specifies the width of each decoded picture that references the PPS, in units of luma samples. pic_width_in_luma_samples shall not be equal to 0, shall be an integer multiple of Max(8, MinCbSizeY), and shall be less than or equal to pic_width_max_in_luma_samples.

[0100] When res_change_in_clvs_allowed_flag is equal to 0, the value of pic_width_in_luma_samples shall be equal to pic_width_max_in_luma_samples.

[0101] pic_height_in_luma_samples specifies the height in luma samples of each decoded picture that references the PPS. pic_height_in_luma_samples shall not be equal to 0, and shall be an integer multiple of Max(8, MinCbSizeY), and shall be less than or equal to pic_height_max_in_luma_samples.

[0102] When res_change_in_clvs_allowed_flag is equal to 0, the value of pic_height_in_luma_samples shall be equal to pic_height_max_in_luma_samples.

[0103] The variables PicWidthInCtbsY, PicHeightInCtbsY, PicSizeInCtbsY, PicWidthInMinCbsY, PicHeightInMinCbsY, PicSizeInMinCbsY, PicSizeInSamplesY, PicWidthInSamplesC, and PicHeightInSamplesC are derived as follows:

[0104] PicWidthInCtbsY=Ceil(pic_width_in_luma_samples÷CtbSizeY) (69)

[0105] PicHeightInCtbsY=Ceil(pic_height_in_luma_samples÷CtbSizeY) (70)

[0106] PicSizeInCtbsY=PicWidthInCtbsY*PicHeightInCtbsY (71)

[0107] PicWidthInMinCbsY=pic_width_in_luma_samples / MinCbSizeY (72)

[0108] PicHeightInMinCbsY=pic_height_in_luma_samples / MinCbSizeY (73)

[0109] PicSizeInMinCbsY=PicWidthInMinCbsY*PicHeightInMinCbsY (74)

[0110] PicSizeInSamplesY=pic_width_in_luma_samples*pic_height_in_luma_samples (75)

[0111] PicWidthInSamplesC=pic_width_in_luma_samples / SubWidthC (76)

[0112] PicHeightInSamplesC=pic_height_in_luma_samples / SubHeightC (77)

[0113] pps_conformance_window_flag equal to 1 indicates that the conformance cropping window offset parameter follows immediately in the PPS. pps_conformance_window_flag equal to 0 indicates that the conformance cropping window offset parameter does not exist in the PPS.

[0114] pps_conf_win_left_offset, pps_conf_win_right_offset, pps_conf_win_top_offset, and pps_conf_win_bottom_offset specify the samples of the picture in the CLVS output from the decoding process, output according to the rectangular area specified in the picture coordinates. When pps_conformance_window_flag is equal to 0, the values ​​of pps_conf_win_left_offset, pps_conf_win_right_offset, pps_conf_win_top_offset, and pps_conf_win_bottom_offset are inferred to be equal to 0.

[0115] The consistent cropping window contains luma samples with horizontal picture coordinates from SubWidthC*pps_conf_win_left_offset to pic_width_in_luma_samples-(SubWidthC*pps_conf_win_right_offset+1), and vertical picture coordinates from SubHeightC*pps_conf_win_top_offset to pic_height_in_luma_samples-(SubHeightC*pps_conf_win_bottom_offset+1), inclusive.

[0116] The value of SubWidthC*(pps_conf_win_left_offset+pps_conf_win_right_offset) should be less than pic_width_in_luma_samples, and the value of SubHeightC*(pps_conf_win_top_offset+pps_conf_win_bottom_offset) should be less than pic_height_in_luma_samples.

[0117] When ChromaArrayType is not equal to 0, the corresponding specified samples of the two chroma arrays are samples with picture coordinates (x / SubWidthC, y / SubHeightC), where (x, y) are the picture coordinates of the specified luma sample.

[0118] NOTE 2 – The consistency crop window offset parameter applies only to output. All internal decoding processes are applied to the uncropped picture size.

[0119] Assume that ppsA and ppsB are any two PPSs that reference the same SPS. The bitstream conformance requirement is that when ppsA and ppsB have the same value of pic_width_in_luma_samples and pic_height_in_luma_samples, ppsA and ppsB shall have the same value of pps_conf_win_left_offset, pps_conf_win_right_offset, pps_conf_win_top_offset, and pps_conf_win_bottom_offset, respectively.

[0120] When pic_width_in_luma_samples is equal to pic_width_max_in_luma_samples and pic_height_in_luma_samples is equal to pic_height_max_in_luma_samples, the bitstream conformance requirement is that pps_conf_win_left_offset, pps_conf_win_right_offset, pps_conf_win_top_offset and pps_conf_win_bottom_offset are equal to sps_conf_win_left_offset, sps_conf_win_right_offset, sps_conf_win_top_offset and sps_conf_win_bottom_offset, respectively.

[0121] scaling_window_explicit_signaling_flag equal to 1 specifies that the scaling window offset parameters are present in the PPS. scaling_window_explicit_signaling_flag equal to 0 specifies that the scaling window offset parameters are not present in the PPS. When res_change_in_clvs_allowed_flag is equal to 0, the value of scaling_window_explicit_signaling_flag shall be equal to 0.

[0122] scaling_win_left_offset, scaling_win_right_offset, scaling_win_top_offset, and scaling_win_bottom_offset specify offsets to the picture size that should be used for scaling calculations. When not present, the values ​​of scaling_win_left_offset, scaling_win_right_offset, scaling_win_top_offset, and scaling_win_bottom_offset 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.

[0123] 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.

[0124] The variables PicOutputWidthL and PicOutputHeightL are derived as follows:

[0125] PicOutputWidthL=pic_width_in_luma_samples- (78)

[0126] SubWidthC*(scaling_win_right_offset+scaling_win_left_offset)

[0127] PicOutputHeightL=pic_height_in_luma_samples- (79)

[0128] SubWidthC*(scaling_win_bottom_offset+scaling_win_top_offset)

[0129] Assume that refPicOutputWidthL and refPicOutputHeightL are the PicOutputWidthL and PicOutputHeightL of the reference picture of the current picture that refers to this PPS. The requirement for bitstream conformance is that all of the following conditions are met:

[0130] –PicOutputWidthL*2 should be greater than or equal to refPicWidthInLumaSamples.

[0131] –PicOutputHeightL*2 should be greater than or equal to refPicHeightInLumaSamples.

[0132] –PicOutputWidthL should be less than or equal to refPicWidthInLumaSamples*8.

[0133] –PicOutputHeightL should be less than or equal to refPicHeightInLumaSamples*8.

[0134] –PicOutputWidthL*pic_width_max_in_luma_samples shall be greater than or equal to refPicOutputWidthL*(pic_width_in_luma_samples-Max(8,MinCbSizeY)).

[0135] –PicOutputHeightL*pic_height_max_in_luma_samples shall be greater than or equal to refPicOutputHeightL*(pic_height_in_luma_samples-Max(8,MinCbSizeY)).

[0136] output_flag_present_flag equal to 1 indicates that the pic_output_flag syntax element is present in the slice header referencing the PPS. output_flag_present_flag equal to 0 indicates that the pic_output_flag syntax element is not present in the slice header referencing the PPS.

[0137] subpic_id_mapping_in_pps_flag equal to 1 specifies that sub-picture ID mapping is signaled in the PPS. subpic_id_mapping_in_pps_flag equal to 0 specifies that sub-picture ID mapping is not signaled in the PPS. If subpic_id_mapping_explicitly_signalled_flag is 0 or subpic_id_mapping_in_sps_flag is equal to 1, the value of subpic_id_mapping_in_pps_flag shall be equal to 0. Otherwise (subpic_id_mapping_explicitly_signalled_flag is equal to 1 and subpic_id_mapping_in_sps_flag is equal to 0), the value of subpic_id_mapping_in_pps_flag shall be equal to 1.

[0138] pps_num_subpics_minus1 shall be equal to sps_num_subpics_minus1.

[0139] pps_subpic_id_len_minus1 shall be equal to sps_subpic_id_len_minus1.

[0140] pps_subpic_id[i] specifies the sub-picture ID of the i-th sub-picture. The length of the pps_subpic_id[i] syntax element is pps_subpic_id_len_minus1+1 bits.

[0141] For each value of i in the range of 0 to sps_num_subpics_minus1 (inclusive), the variable SubpicIdVal[i] is derived as follows:

[0142]

[0143]

[0144] The requirement for bitstream conformance is that the following two constraints apply:

[0145] --For any two different values ​​of i and j in the range of 0 to sps_num_subpics_minus1 (inclusive), SubpicIdVal[i] shall not be equal to SubpicIdVal[j].

[0146] --When the current picture is not the first picture of the CLVS, for each value of i in the range of 0 to sps_num_subpics_minus1 (inclusive), if the value of SubpicIdVal[i] is not equal to the value of SubpicIdVal[i] of the previous picture in the same layer in decoding order, the nal_unit_type of all codec slice NAL units of the subpictures in the current picture with subpicture index i shall be equal to a specific value in the range of IDR_W_RADL to CRA_NUT (inclusive).

[0147] no_pic_partition_flag equal to 1 specifies that no picture partitioning is applied to each picture of the referenced PPS. no_pic_partition_flag equal to 0 specifies that each picture of the referenced PPS may be partitioned into multiple slices or slices.

[0148] A bitstream conformance requirement is that the value of no_pic_partition_flag should be the same for all PPSs referenced by a coded picture within a CLVS.

[0149] It is a bitstream conformance requirement that when the value of sps_num_subpics_minus1+1 is greater than 1, the value of no_pic_partition_flag shall not be equal to 1.

[0150] pps_log2_ctu_size_minus5 plus 5 specifies the luma codec treeblock size for each CTU. pps_log2_ctu_size_minus5 shall be equal to sps_log2_ctu_size_minus5.

[0151] num_exp_tile_columns_minus1 plus 1 specifies the number of explicitly provided tile column widths. The value of num_exp_tile_columns_minus1 shall be in the range of 0 to PicWidthInCtbsY–1, inclusive. When no_pic_partition_flag is equal to 1, the value of num_exp_tile_columns_minus1 is inferred to be equal to 0.

[0152] num_exp_tile_rows_minus1 plus 1 specifies the number of explicitly provided tile row heights. The value of num_exp_tile_rows_minus1 shall be in the range of 0 to PicHeightInCtbsY–1, inclusive. When no_pic_partition_flag is equal to 1, the value of num_tile_rows_minus1 is inferred to be equal to 0.

[0153] tile_column_width_minus1[i] plus 1 specifies the width of the i-th tile column for i in the range 0 to num_exp_tile_columns_minus1-1 (inclusive) in units of CTBs. tile_column_width_minus1[num_exp_tile_columns_minus1] is used to derive the width of tile columns with indices greater than or equal to num_exp_tile_columns_minus1 as specified in clause 6.5.1. The value of tile_column_width_minus1[i] shall be in the range 0 to PicWidthInCtbsY–1 (inclusive). When not present, the value of tile_column_width_minus1[0] is inferred to be equal to PicWidthInCtbsY-1.

[0154] tile_row_height_minus1[i] plus 1 specifies the height of the i-th tile row for i in the range 0 to num_exp_tile_rows_minus1-1 (inclusive) in units of CTBs. tile_row_height_minus1[num_exp_tile_rows_minus1] is used to derive the height of tile rows for indices greater than or equal to num_exp_tile_rows_minus1 as specified in clause 6.5.1. The value of tile_row_height_minus1[i] shall be in the range 0 to PicHeightInCtbsY–1 (inclusive). When not present, the value of tile_row_height_minus1[0] is inferred to be equal to PicHeightInCtbsY-1.

[0155] rect_slice_flag equal to 0 specifies that the slices within each slice are in raster scan order, and the slice information is not signaled in the PPS. rect_slice_flag equal to 1 specifies that the slices within each slice cover a rectangular area of ​​the picture, and the slice information is signaled in the PPS. When not present, rect_slice_flag is inferred to be equal to 1. When subpic_info_present_flag is equal to 1, the value of rect_slice_flag shall be equal to 1.

[0156] single_slice_per_subpic_flag equal to 1 specifies that each sub-picture consists of one and only one rectangular slice. single_slice_per_subpic_flag equal to 0 specifies that each sub-picture may consist of one or more rectangular slices. When single_slice_per_subpic_flag is equal to 1, num_slices_in_pic_minus1 is inferred to be equal to sps_num_subpics_minus1. When not present, the value of single_slice_per_subpic_flag is inferred to be equal to 0.

[0157] num_slices_in_pic_minus1 plus 1 specifies the number of rectangular slices in each picture referencing the PPS. The value of num_slices_in_pic_minus1 shall be in the range of 0 to MaxSlicesPerPicture–1, inclusive, where MaxSlicesPerPicture is specified in Annex A. When no_pic_partition_flag is equal to 1, the value of num_slices_in_pic_minus1 is inferred to be equal to 0.

[0158] tile_idx_delta_present_flag equal to 0 specifies that tile_idx_delta values ​​are not present in the PPS, and all rectangular slices in pictures referencing the PPS are specified in raster order according to the procedure defined in clause 6.5.1. tile_idx_delta_present_flag equal to 1 specifies that tile_idx_delta values ​​may be present in the PPS, and all rectangular slices in pictures referencing the PPS are specified in the order indicated by the tile_idx_delta values. When not present, the value of tile_idx_delta_present_flag is inferred to be equal to 0.

[0159] slice_width_in_tiles_minus1[i] plus 1 specifies the width of the i-th rectangular strip in units of tile columns. The value of slice_width_in_tiles_minus1[i] shall be in the range of 0 to NumTileColumns–1 (inclusive).

[0160] When slice_width_in_tiles_minus1[i] is not present, the following applies:

[0161] --If NumTileColumns is equal to 1, the value of slice_width_in_tiles_minus1[i] is inferred to be equal to 0.

[0162] -- Otherwise, the value of slice_width_in_tiles_minus1[i] is inferred as specified in clause 6.5.1.

[0163] slice_height_in_tiles_minus1[i] plus 1 specifies the height of the i-th rectangular strip in units of tile rows. The value of slice_height_in_tiles_minus1[i] shall be in the range of 0 to NumTileRows–1 (inclusive).

[0164] When slice_height_in_tiles_minus1[i] is not present, the following applies:

[0165] --If NumTileRows is equal to 1, or tile_idx_delta_present_flag is equal to 0, and tileIdx%NumTileColumns is greater than 0, then the value of slice_height_in_tiles_minus1[i] is inferred to be equal to 0.

[0166] --Otherwise (NumTileRows is not equal to 1, and tile_idx_delta_present_flag is equal to 1 or tileIdx%NumTileColumns is equal to 0), when tile_idx_delta_present_flag is equal to 1 or tileIdx%NumTileColumns is equal to 0, the value of slice_height_in_tiles_minus1[i] is inferred to be equal to slice_height_in_tiles_minus1[i-1].

[0167] num_exp_slices_in_tile[i] specifies the number of strip heights explicitly provided in the current tile containing multiple rectangular strips. The value of num_exp_slices_in_tile[i] shall be in the range of 0 to RowHeight[tileY]–1 (inclusive), where tileY is the index of the tile row containing the i-th strip. When not present, the value of num_exp_slices_in_tile[i] is inferred to be equal to 0. When num_exp_slices_in_tile[i] is equal to 0, the value of the variable NumSlicesInTile[i] is derived to be equal to 1.

[0168] exp_slice_height_in_ctus_minus1[j] plus 1 specifies the height of the j-th rectangular slice in the current slice in CTU rows. The value of exp_slice_height_in_ctus_minus1[j] shall be in the range of 0 to RowHeight[tileY]–1 (inclusive), where tileY is the slice row index of the current slice.

[0169] When num_exp_slices_in_tile[i] is greater than 0, the variables NumSlicesInTile[i] and SliceHeightInCtusMinus1[i+k] with k in the range of 0 to NumSlicesInTile[i]-1 (inclusive) are derived as follows:

[0170]

[0171] tile_idx_delta[i] specifies the difference between the tile index of the first tile in the i-th rectangular strip and the tile index of the first tile in the i+1-th rectangular strip. The value of tile_idx_delta[i] shall be in the range -NumTilesInPic+1 to NumTilesInPic–1, inclusive. When not present, the value of tile_idx_delta[i] is inferred to be equal to 0. When present, the value of tile_idx_delta[i] shall not be equal to 0.

[0172] loop_filter_across_tiles_enabled_flag equal to 1 specifies that loop filtering operations may be performed across slice boundaries in pictures that reference the PPS. loop_filter_cross_tiles_enabled_flag equal to 0 specifies that loop filtering operations are not performed across slice boundaries in pictures that reference the PPS. Loop filtering operations include deblocking filter, sample adaptive offset filter, and adaptive loop filter operations. When not present, the value of loop_filter_cross_tiles_enabled_flag is inferred to be equal to 1.

[0173] loop_filter_cross_slices_enabled_flag equal to 1 specifies that loop filtering operations may be performed across slice boundaries in pictures that reference a PPS. loop_filter_cross_slice_enabled_flag equal to 0 specifies that loop filtering operations are not performed across slice boundaries in pictures that reference a PPS. Loop filtering operations include deblocking filter, sample adaptive offset filter, and adaptive loop filter operations. When not present, the value of loop_filter_cross_slices_enabled_flag is inferred to be equal to 0.

[0174] cabac_init_present_flag equal to 1 specifies that cabac_init_flag is present in the slice header of the referenced PPS. cabac_init_present_flag equal to 0 specifies that cabac_init_flag is not present in the slice header of the referenced PPS.

[0175] num_ref_idx_default_active_minus1[i] increments by 1 and, when equal to 0, specifies the inferred value of the variable NumRefIdxActive[0] for a P slice or B slice with num_ref_idx_active_override_flag equal to 0, and, when i is equal to 1, specifies the inferred value of NumRefIdxActive[1] for a B slice with num_ref_idx_active_override_flag equal to 0. The value of num_ref_idx_default_active_minus1[i] shall be in the range of 0 to 14, inclusive.

[0176] rpl1_idx_present_flag equal to 0 specifies that ref_pic_list_sps_flag[1] and ref_pic_list_idx[1] are not present in the PH syntax structure or in the slice header of the pictures referencing the PPS. rpl1_idx_present_flag equal to 1 specifies that ref_pic_list_sps_flag[1] and ref_pic_list_idx[1] may be present in the PH syntax structure or in the slice header of the pictures referencing the PPS.

[0177] init_qp_minus26 plus 26 specifies the SliceQp of each slice of the reference PPS Y When a non-zero value of ph_qp_delta is decoded, SliceQp Y The initial value of SliceQp is modified at the picture level, or when a non-zero value of slice_qp_delta is decoded. Y The initial value of init_qp_minus26 is modified at the stripe level. The value of init_qp_minus26 should be in the range of -(26+QpBdOffset) to +37 (inclusive).

[0178] cu_qp_delta_enabled_flag equal to 1 specifies that ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slice syntax elements are present in the PH referencing the PPS and cu_qp_delta_abs may be present in the transform unit syntax. cu_qp_delta_enabled_flag equal to 0 specifies that ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slice syntax elements are not present in the PH referencing the PPS and cu_qp_delta_abs is not present in the transform unit syntax.

[0179] pps_chroma_tool_offsets_present_flag equal to 1 specifies that syntax elements related to chroma tool offsets are present in the PPS RBSP syntax structure. pps_chroma_tool_offsets_present_flag equal to 0 specifies that syntax elements related to chroma tool offsets are not present in the PPS RBSP syntax structure. When ChromaArrayType is equal to 0, the value of pps_chroma_tool_offsets_present_flag shall be equal to 0.

[0180] pps_cb_qp_offset and pps_cr_qp_offset are defined to derive Qp′ Cb and Qp′ Cr The brightness quantization parameter Qp′ Y The value of pps_cb_qp_offset and the value of pps_cr_qp_offset should be in the range of -12 to +12 (inclusive). When ChromaArrayType is equal to 0, pps_cb_qp_offset and pps_cr_qp_offset are not used in the decoding process and the decoder should ignore their values. When not present, the values ​​of pps_cb_qp_offset and pps_cr_qp_offset are inferred to be equal to 0.

[0181] pps_joint_cbcr_qp_offset_present_flag equal to 1 specifies that pps_joint_cbcr_qp_offset_value and joint_cbcr_qp_offset_list[i] are present in the PPS RBSP syntax structure. pps_joint_cbcr_qp_offset_present_flag equal to 0 specifies that pps_joint_cbcr_qp_offset_value and joint_cbcr_qp_offset_list[i] are not present in the PPS RBSP syntax structure. When ChromaArrayType is equal to 0 or sps_joint_cbcr_enabled_flag is equal to 0, the value of pps_joint_cbcr_qp_offset_present_flag shall be equal to 0. When not present, the value of pps_joint_cbcr_qp_offset_present_flag is inferred to be equal to 0.

[0182] pps_joint_cbcr_qp_offset_value is defined to derive Qp′ CbCr The brightness quantization parameter Qp′ YThe value of pps_joint_cbcr_qp_offset_value shall be in the range of -12 to +12 (inclusive). When ChromaArrayType is equal to 0 or sps_joint_cbcr_enabled_flag is equal to 0, pps_joint_cbcr_qp_offset_value is not used during decoding and the decoder shall ignore its value. When pps_joint_cbcr_qp_offset_present_flag is equal to 0, pps_joint_cbcr_qp_offset_value does not exist and is inferred to be equal to 0.

[0183] pps_slice_chroma_qp_offsets_present_flag equal to 1 specifies that the slice_cb_qp_offset and slice_cr_qp_offset syntax elements are present in the associated slice header. pps_slice_chroma_qp_offsets_present_flag equal to 0 specifies that the slice_cb_qp_offset and slice_cr_qp_offset syntax elements are not present in the associated slice header. When not present, the value of pps_slice_chroma_qp_offsets_present_flag is inferred to be equal to 0.

[0184] pps_cu_chroma_qp_offset_list_enabled_flag equal to 1 specifies that the ph_cu_chroma_qp_offset_subdiv_intra_slice and ph_cu_chroma_qp_offset_subdiv_inter_slice syntax elements are present in the PH referencing the PPS, and that cu_chroma_qp_offset_flag may be present in transform unit syntax and palette codec syntax. pps_cu_chroma_qp_offset_list_enabled_flag equal to 0 specifies that the ph_cu_chroma_qp_offset_subdiv_intra_slice and ph_cu_chroma_qp_offset_subdiv_inter_slice syntax elements are not present in the PH referencing the PPS, and that cu_chroma_qp_offset_flag is not present in transform unit syntax and palette codec syntax. When not present, the value of pps_cu_chroma_qp_offset_list_enabled_flag is inferred to be equal to 0.

[0185] chroma_qp_offset_list_len_minus1 plus 1 specifies the number of syntax elements cb_qp_offset_list[i], cr_qp_offset_list[i] and joint_cbcr_qp_offset_list[i] present in the PPS RBSP syntax structure. The value of chroma_qp_offset_list_len_minus1 shall be in the range of 0 to 5 (inclusive).

[0186] cb_qp_offset_list[i], cr_qp_offset_list[i] and joint_cbcr_qp_offset_list[i] respectively specify Qp′ Cb , Qp′ Cr and Qp′ CbCr The offset used in the derivation of . The values ​​of cb_qp_offset_list[i], cr_qp_offset_list[i], and joint_cbcr_qp_offset_list[i] shall be in the range -12 to +12 (inclusive). When pps_joint_cbcr_qp_offset_present_flag is equal to 0, joint_cbcr_qp_offset_list[i] is not present and is inferred to be equal to 0.

[0187] pps_weighted_pred_flag equal to 0 specifies that weighted prediction is not applied to P slices that reference a PPS. pps_weighted_pred_flag equal to 1 specifies that weighted prediction is applied to P slices that reference a PPS. When sps_weighted_pred_flag is equal to 0, the value of pps_weighted_pred_flag shall be equal to 0.

[0188] pps_weighted_bipred_flag equal to 0 specifies that explicit weighted prediction is not applied to B slices referencing the PPS. pps_weighted_bipred_flag equal to 1 specifies that explicit weighted prediction is applied to B slices referencing the PPS. When sps_weighted_bipred_flag is equal to 0, the value of pps_weighted_bipred_flag shall be equal to 0.

[0189] deblocking_filter_control_present_flag equal to 1 specifies that the deblocking filter control syntax element is present in the PPS. deblocking_filter_control_present_flag equal to 0 specifies that the deblocking filter control syntax element is not present in the PPS.

[0190] deblocking_filter_override_enabled_flag equal to 1 specifies that ph_deblocking_filter_override_flag is present in the PH of the referenced PPS, or slice_deblocking_filter_override_flag is present in the slice header of the referenced PPS. deblocking_filter_override_enabled_flag equal to 0 specifies that ph_deblocking_filter_override_flag is not present in the PH of the referenced PPS, or slice_deblocking_filter_override_flag is not present in the slice header of the referenced PPS. When not present, the value of deblocking_filter_override_enabled_flag is inferred to be equal to 0.

[0191] pps_deblocking_filter_disabled_flag equal to 1 specifies that the operation of the deblocking filter is not applied to slices referencing a PPS for which slice_deblocking_filter_disabled_flag is not present. pps_deblocking_filter_disabled_flag equal to 0 specifies that the operation of the deblocking filter is applied to slices referencing a PPS for which slice_deblocking_filter_disabled_flag is not present. When not present, the value of pps_deblocking_filter_disabled_flag is inferred to be equal to 0.

[0192] pps_beta_offset_div2 and pps_tc_offset_div2 specify default deblocking parameter offsets for β and tC (divided by 2) that are applied to the luma component of slices referencing the PPS, unless the default deblocking parameter offsets are overridden by deblocking parameter offsets present in the picture header or slice header of slices referencing the PPS. The values ​​of pps_beta_offset_div2 and pps_tc_offset_div2 shall both be in the range -12 to 12 (inclusive). When not present, the values ​​of pps_beta_offset_div2 and pps_tc_offset_div2 are both inferred to be equal to 0.

[0193] pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 specify default deblocking parameter offsets for β and tC (divided by 2) that are applied to the Cb component of slices referencing the PPS, unless the default deblocking parameter offsets are overridden by deblocking parameter offsets present in the picture header or slice header of slices referencing the PPS. The values ​​of pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 shall both be in the range -12 to 12, inclusive. When not present, the values ​​of pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 are both inferred to be equal to 0.

[0194] pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 specify default deblocking parameter offsets for β and tC (divided by 2) that are applied to the Cr component of slices referencing the PPS, unless the default deblocking parameter offsets are overridden by deblocking parameter offsets present in the picture header or slice header of slices referencing the PPS. The values ​​of pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 shall both be in the range -12 to 12, inclusive. When not present, the values ​​of pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 are both inferred to be equal to 0.

[0195] rpl_info_in_ph_flag equal to 1 specifies that the reference picture list information is present in the PH syntax structure and not in the slice headers referencing a PPS that does not contain the PH syntax structure. rpl_info_in_ph_flag equal to 0 specifies that the reference picture list information is not present in the PH syntax structure and may be present in the slice headers referencing a PPS that does not contain the PH syntax structure.

[0196] dbf_info_in_ph_flag equal to 1 specifies that the deblocking filter information is present in the PH syntax structure and not in the slice headers referencing a PPS that does not contain a PH syntax structure. dbf_info_in_ph_flag equal to 0 specifies that the deblocking filter information is not present in the PH syntax structure and may be present in the slice headers referencing a PPS that does not contain a PH syntax structure. When not present, the value of dbf_info_in_ph_flag is inferred to be equal to 0.

[0197] sao_info_in_ph_flag equal to 1 specifies that SAO filter information is present in the PH syntax structure and not in slice headers referencing a PPS that does not contain a PH syntax structure. sao_info_in_ph_flag equal to 0 specifies that SAO filter information is not present in the PH syntax structure and may be present in slice headers referencing a PPS that does not contain a PH syntax structure.

[0198] alf_info_in_ph_flag equal to 1 specifies that ALF information is present in the PH syntax structure and not in slice headers referencing PPSs that do not contain the PH syntax structure. alf_info_in_ph_flag equal to 0 specifies that ALF information is not present in the PH syntax structure and may be present in slice headers referencing PPSs that do not contain the PH syntax structure.

[0199] wp_info_in_ph_flag equal to 1 specifies that weighted prediction information may be present in the PH syntax structure, but not in slice headers referencing a PPS that does not contain a PH syntax structure. wp_info_in_ph_flag equal to 0 specifies that weighted prediction information is not present in the PH syntax structure, and may be present in slice headers referencing a PPS that does not contain a PH syntax structure. When not present, the value of wp_info_in_ph_flag is inferred to be equal to 0.

[0200] qp_delta_info_in_ph_flag equal to 1 specifies that QP delta information is present in the PH syntax structure and not in slice headers referencing PPSs that do not contain the PH syntax structure. qp_delta_info_in_ph_flag equal to 0 specifies that QP delta information is not present in the PH syntax structure and may be present in slice headers referencing PPSs that do not contain the PH syntax structure.

[0201] pps_ref_wraparound_enabled_flag equal to 1 specifies that horizontal wraparound motion compensation is applied in inter prediction. pps_ref_wraparound_enabled_flag equal to 0 specifies that horizontal wraparound motion compensation is not applied. When the value of CtbSizeY / MinCbSizeY+1 is greater than pic_width_in_luma_samples / MinCbSizeY-1, the value of pps_ref_wraparound_enabled_flag shall be equal to 0. When sps_ref_wraparound_enabled_flag is equal to 0, the value of pps_ref_wraparound_enabled_flag shall be equal to 0.

[0202] pps_ref_wraparound_offset plus (CtbSizeY / MinCbSizeY)+2 specifies the offset used to calculate the horizontal wrapping position in units of MinCbSizeY luma samples. The value of pps_ref_wraparound_offset shall be in the range of 0 to (pic_width_in_luma_samples / MinCbSizeY)-(CtbSizeY / MinCbSizeY)-2, inclusive.

[0203] The variable PpsRefWraparoundOffset is set equal to pps_ref_wraparound_offset+(CtbSizeY / MinCbSizeY)+2.

[0204] picture_header_extension_present_flag equal to 0 specifies that the PH extension syntax element is not present in the PH referencing the PPS. picture_header_extension_present_flag equal to 1 specifies that the PH extension syntax element is present in the PH referencing the PPS. picture_header_extension_present_flag shall be equal to 0 in bitstreams conforming to this version of this specification.

[0205] slice_header_extension_present_flag equal to 0 specifies that the slice header extension syntax element is not present in the slice header of the codec pictures referencing the PPS. slice_header_extension_present_flag equal to 1 specifies that the slice header extension syntax element is present in the slice header of the codec pictures referencing the PPS. slice_header_extension_present_flag shall be equal to 0 in bitstreams conforming to this version of this specification.

[0206] pps_extension_flag equal to 0 specifies that the pps_extension_data_flag syntax element is not present in the PPS RBSP syntax structure. pps_extension_flag equal to 1 specifies that the pps_extension_data_flag syntax element is present in the PPS RBSP syntax structure.

[0207] pps_extension_data_flag can have any value. Its presence and value do not affect decoder conformance to the profiles specified in this version of this specification. Decoders conforming to this version of this specification shall ignore all pps_extension_data_flag syntax elements.

[0208] PH Syntax and Semantics

[0209] In the latest VVC draft text, the PH syntax and semantics are as follows:

[0210]

[0211] The PH RBSP contains the PH syntax structure, namely picture_header_structure().

[0212]

[0213]

[0214]

[0215]

[0216]

[0217]

[0218]

[0219] The PH syntax structure contains information common to all slices of the coded picture associated with the PH syntax structure.

[0220] gdr_or_irap_pic_flag equal to 1 specifies that the current picture is a GDR picture or an IRAP picture. gdr_or_irap_pic_flag equal to 0 specifies that the current picture may or may not be a GDR picture or an IRAP picture.

[0221] gdr_pic_flag equal to 1 specifies that the picture associated with the PH is a GDR picture. gdr_pic_flag equal to 0 specifies that the picture associated with the PH is not a GDR picture. When not present, the value of gdr_pic_flag is inferred to be equal to 0. When gdr_enabled_flag is equal to 0, the value of gdr_pic_flag shall be equal to 0.

[0222] ph_inter_slice_allowed_flag equal to 0 specifies that all codec slices of the picture have slice_type equal to 2. ph_inter_slice_allowed_flag equal to 1 specifies that there may or may not be one or more codec slices with slice_type equal to 0 or 1 in the picture.

[0223] ph_intra_slice_allowed_flag equal to 0 specifies that all codec slices of the picture have slice_type equal to 0 or 1. ph_intra_slice_allowed_flag equal to 1 specifies that the picture may or may not have one or more codec slices with slice_type equal to 2. When not present, the value of ph_intra_slice_allowed_flag is inferred to be equal to 1.

[0224] NOTE 1 – For bitstreams where sub-picture based bitstream merging should be performed without changing the PH NAL units, the codec shall set the values ​​of ph_inter_slice_allowed_flag and ph_intra_slice_allowed_flag equal to 1.

[0225] non_reference_picture_flag equal to 1 specifies that the picture associated with the PH is never used as a reference picture. non_reference_picture_flag equal to 0 specifies that the picture associated with the PH may or may not be used as a reference picture.

[0226] ph_pic_parameter_set_id specifies the value of pps_pic_parameter_set_id for the PPS being used. The value of ph_pic_parameter_set_id shall be in the range of 0 to 63 (inclusive).

[0227] The bitstream conformance requirement is that the value of TemporalId of the PH shall be greater than or equal to the value of TemporalId of the PPS with pps_pic_parameter_set_id equal to ph_pic_parameter_set_id.

[0228] ph_pic_order_cnt_lsb specifies the picture order count modulo MaxPicOrderCntLsb of the current picture. The length of the ph_pic_order_cnt_lsb syntax element is log2_max_pic_order_cnt_lsb_minus4+4 bits. The value of ph_pic_order_cnt_lsb shall be in the range of 0 to MaxPicOrderCntLsb–1, inclusive.

[0229] no_output_of_prior_pics_flag affects the output of previously decoded pictures in the DPB after decoding a CLVSS picture that is not the first picture in the bitstream as specified in Annex C.

[0230] recovery_poc_cnt specifies the recovery point of the decoded picture in output order. If the current picture is a GDR picture associated with PH, and there is a picture picA in CLVS that follows the current GDR picture in decoding order, whose PicOrderCntVal is equal to the PicOrderCntVal of the current GDR picture plus the value of recovery_poc_cnt, then the picture picA is called the recovery point picture. Otherwise, the first picture in the output order whose PicOrderCntVal is greater than the PicOrderCntVal of the current picture plus the value of recovery_poc_cnt is called the recovery point picture. In decoding order, the recovery point picture should not precede the current GDR picture. The value of recovery_poc_cnt should be in the range of 0 to MaxPicOrderCntLsb–1 (including the end value).

[0231] When the current picture is a GDR picture, the variable RpPicOrderCntVal is derived as follows:

[0232] RpPicOrderCntVal=PicOrderCntVal+recovery_poc_cnt (82)

[0233] NOTE 2 – When gdr_enabled_flag is equal to 1 and the PicOrderCntVal of the current picture is greater than or equal to the RpPicOrderCntVal of the associated GDR picture, the current and subsequent decoded pictures in output order exactly match the corresponding pictures produced by starting the decoding process from the previous IRAP picture (if any) preceding the associated GDR picture in decoding order.

[0234] ph_extra_bit[i] may be equal to 1 or 0. A decoder conforming to this version of this specification shall ignore the value of ph_extra_bit[i]. Its value shall not affect the conformance of the decoder to the profile specified in this version of this specification.

[0235] ph_poc_msb_present_flag equal to 1 specifies that the syntax element poc_msb_val is present in the PH. ph_poc_msb_present_flag equal to 0 specifies that the syntax element poc_msb_val is not present in the PH. The value of ph_poc_msb_present_flag shall be 0 when vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is equal to 0 and there is a picture in the current AU in the reference layer of the current layer.

[0236] poc_msb_val specifies the POC MSB value of the current picture. The length of the syntax element poc_msb_val is poc_msb_len_minus1+1 bits.

[0237] ph_alf_enabled_flag equal to 1 specifies that the adaptive loop filter is enabled for all slices associated with the PH and may be applied to the Y, Cb or Cr color components in the slice. ph_alf_enabled_flag equal to 0 specifies that the adaptive loop filter may be disabled for one or more or all slices associated with the PH. When not present, ph_alf_enabled_flag is inferred to be equal to 0.

[0238] ph_num_alf_aps_ids_luma specifies the number of ALF APSs referenced by the slice associated with the PH.

[0239] ph_alf_aps_id_luma[i] specifies the adaptation_parameter_set_id of the i-th ALF APS to which the luma components of the slices associated with the PH refer.

[0240] The value of alf_luma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_luma[i].

[0241] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_luma[i] shall be less than or equal to the TemporalId of the picture associated with the PH.

[0242] ph_alf_chroma_idc equal to 0 specifies that the adaptive loop filter is not applied to the Cb color component and the Cr color component. ph_alf_chroma_idc equal to 1 indicates that the adaptive loop filter is applied to the Cb color component. ph_alf_chroma_idc equal to 2 indicates that the adaptive loop filter is applied to the Cr color component. ph_alf_chroma_idc equal to 3 indicates that the adaptive loop filter is applied to the Cb color component and the Cr color component. When ph_alf_chroma_idc is not present, it is inferred to be equal to 0.

[0243] ph_alf_aps_id_chroma specifies the adaptation_parameter_set_id of the ALF APS to which the chroma components of the slice associated with the PH refer.

[0244] The value of alf_chroma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_chroma.

[0245] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_chroma shall be less than or equal to the TemporalId of the picture associated with the PH.

[0246] ph_cc_alf_cb_enabled_flag equal to 1 specifies that the cross-component filter of the Cb color component is enabled for all slices associated with the PH and may be applied to the Cb color components in the slice. ph_cc_alf_cb_enabled_flag equal to 0 specifies that the cross-component filter of the Cb color component may be disabled for one, multiple or all slices associated with the PH. When not present, ph_cc_alf_cb_enabled_flag is inferred to be equal to 0.

[0247] ph_cc_alf_cb_aps_id specifies the adaptation_parameter_set_id of the ALF APS referenced by the Cb color component of the slice associated with the PH.

[0248] The value of alf_cc_cb_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cb_aps_id.

[0249] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cb_aps_id shall be less than or equal to the TemporalId of the picture associated with the PH.

[0250] ph_cc_alf_cr_enabled_flag equal to 1 specifies that cross-component filters for Cr color components are enabled for all slices associated with the PH and may be applied to Cr color components in a slice. ph_cc_alf_cr_enabled_flag equal to 0 specifies that cross-component filters for Cr color components may be disabled for one, multiple or all slices associated with the PH. When not present, ph_cc_alf_cr_enabled_flag is inferred to be equal to 0.

[0251] ph_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id of the ALF APS referenced by the Cr color components of the slice associated with the PH.

[0252] The value of alf_cc_cr_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cr_aps_id.

[0253] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cr_aps_id shall be less than or equal to the TemporalId of the picture associated with the PH.

[0254] ph_lmcs_enabled_flag equal to 1 specifies that luma mapping with chroma scaling is enabled for all slices associated with PH, ph_lmcs_enabled_flag equal to 0 specifies that luma mapping with chroma scaling is disabled for one, multiple or all slices associated with PH, and when not present, the value of ph_lmcs_enabled_flag is inferred to be equal to 0.

[0255] ph_lmcs_aps_id specifies the adaptation_parameter_set_id of the LMCS APS referenced by the slice associated with the PH. The TemporalId of the APS NAL unit with aps_params_type equal to LMCS_APS and adaptation_parameter_set_id equal to ph_lmcs_aps_id shall be less than or equal to the TemporalId of the picture associated with the PH.

[0256] ph_chroma_residual_scale_flag equal to 1 specifies that chroma residual scaling is enabled for all slices associated with PH. ph_chroma_residual_scale_flag equal to 0 specifies that chroma residual scaling may be disabled for one, multiple, or all slices associated with PH. When ph_chroma_residual_scale_flag is not present, it is inferred to be equal to 0.

[0257] ph_scaling_list_present_flag equal to 1 specifies that the scaling list data for the slices associated with the PH is derived based on the scaling list data contained in the reference scaling list APS. ph_scaling_list_present_flag equal to 0 specifies that the scaling list data for the slices associated with the PH is set equal to 16. When not present, the value of ph_scaling_list_present_flag is inferred to be equal to 0.

[0258] ph_scaling_list_aps_id specifies the adaptation_parameter_set_id of the scaling list APS. The TemporalId of the APS NAL unit with aps_params_type equal to SCALING_APS and adaptation_parameter_set_id equal to ph_scaling_list_aps_id shall be less than or equal to the TemporalId of the picture associated with the PH.

[0259] ph_virtual_boundaries_present_flag equal to 1 specifies that information about virtual boundaries is signaled in the PH. ph_virtual_boundaries_present_flag equal to 0 specifies that information about virtual boundaries is not signaled in the PH. When one or more virtual boundaries are signaled in the PH, loop filtering operations are disabled across virtual boundaries in the picture. Loop filtering operations include deblocking filter, sample adaptive offset filter, and adaptive loop filter operations. When not present, the value of ph_virtual_boundaries_present_flag is inferred to be equal to 0.

[0260] A bitstream conformance requirement is that when subpic_info_present_flag is equal to 1, the value of ph_virtual_boundaries_present_flag shall be equal to 0.

[0261] The variable VirtualBoundariesPresentFlag is exported as follows:

[0262]

[0263] ph_num_ver_virtual_boundaries specifies the number of ph_virtual_boundaries_pos_x[i] syntax elements present in the PH. When ph_num_ver_virtual_boundaries is not present, it is inferred to be equal to 0.

[0264] The variable NumVerVirtualBoundaries is exported as follows:

[0265]

[0266] ph_virtual_boundaries_pos_x[i] specifies the position of the i-th vertical virtual boundary in units of luma samples divided by 8. The value of ph_virtual_boundaries_pos_x[i] shall be in the range of 1 to Ceil(pic_width_in_luma_samples÷8)–1, inclusive.

[0267] The list VirtualBoundariesPosX[i], where i ranges from 0 to NumVerVirtualBoundaries–1 (inclusive), specifies the position of the vertical virtual boundaries in units of luma samples and is derived as follows:

[0268] for(i=0;i <NumVerVirtualBoundaries;i++)

[0269] VirtualBoundariesPosX[i]=(sps_virtual_boundaries_present_flag?

[0270] sps_virtual_boundaries_pos_x[i]:ph_virtual_boundaries_pos_x[i])*8(85)

[0271] The distance between any two vertical virtual boundaries should be greater than or equal to CtbSizeY luminance samples.

[0272] ph_num_hor_virtual_boundaries specifies the number of ph_virtual_boundaries_pos_y[i] syntax elements present in the PH. When ph_num_hor_virtual_boundaries is not present, it is inferred to be equal to 0.

[0273] The parameter NumHorVirtualBoundaries is derived as follows:

[0274]

[0275] When sps_virtual_boundaries_enabled_flag is equal to 1 and ph_virtual_boundaries_present_flag is equal to 1, the sum of ph_num_ver_virtual_boundaries and ph_num_hor_virtual_boundaries shall be greater than zero.

[0276] ph_virtual_boundaries_pos_y[i] specifies the position of the i-th horizontal virtual boundary in units of luma samples divided by 8. The value of ph_virtual_boundaries_pos_y[i] shall be in the range of 1 to Ceil(pic_height_in_luma_samples÷8)–1, inclusive.

[0277] The list VirtualBoundariesPosY[i], where i ranges from 0 to NumHorVirtualBoundaries–1 (inclusive), specifies the position of the horizontal virtual boundaries in units of luma samples and is derived as follows:

[0278] for(i=0;i <NumHorVirtualBoundaries;i++)

[0279] VirtualBoundariesPosY[i]=(sps_virtual_boundaries_present_flag?

[0280] sps_virtual_boundaries_pos_y[i]:ph_virtual_boundaries_pos_y[i])*8(87)

[0281] The distance between any two horizontal virtual boundaries should be greater than or equal to CtbSizeY luminance samples.

[0282] pic_output_flag affects the decoded picture output and removal process as specified in Annex C. When pic_output_flag is not present, it is inferred to be equal to 1.

[0283] partition_constraints_override_flag equal to 1 specifies that the partition constraints parameters are present in the PH. partition_constraints_override_flag equal to 0 specifies that the partition constraints parameters are not present in the PH. When not present, the value of partition_constraints_override_flag is inferred to be equal to 0.

[0284] ph_log2_diff_min_qt_min_cb_intra_slice_luma specifies the difference between the base 2 logarithm of the minimum size of luma samples of luma leaf blocks resulting from quadtree partitioning of the CTU and the base 2 logarithm of the minimum decoded block size of luma samples of luma CUs in slices with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_min_qt_min_cb_intra_slice_luma shall be in the range of 0 to CtbLog2SizeY-MinCbLog2SizeY, inclusive. When not present, the value of ph_log2_diff_min_qt_min_cb_luma is inferred to be equal to sps_log2_diff_min_qt_min_cb_intra_slice_luma.

[0285] ph_max_mtt_hierarchy_depth_intra_slice_luma specifies the maximum hierarchical depth of codec units resulting from multi-type tree partitioning of quadtree leaves in slices with slice_type equal to 2 (I) associated with the PH. The value of ph_max_mtt_hierarchy_depth_intra_slice_luma shall be in the range of 0 to 2*(CtbLog2SizeY - MinCbLog2SizeY), inclusive. When not present, the value of ph_max_mtt_hierarchy_depth_intra_slice_luma is inferred to be equal to sps_max_mtt_hierarchy_depth_intra_slice_luma.

[0286] ph_log2_diff_max_bt_min_qt_intra_slice_luma specifies the difference between the base 2 logarithm of the maximum dimension (width or height) in the luma samples of a luma codec block that can be partitioned using binary partitioning and the base 2 logarithm of the minimum dimension (width or height) in the luma samples of a luma leaf block resulting from a quadtree partitioning of a CTU in a slice with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_max_bt_min_qt_intra_slice_luma shall be in the range of 0 to CtbLog2SizeY - MinQtLog2SizeIntraY, inclusive. When not present, the value of ph_log2_diff_max_bt_min_qt_intra_slice_luma is inferred to be equal to sps_log2_diff_max_bt_min_qt_intra_slice_luma.

[0287] ph_log2_diff_max_tt_min_qt_intra_slice_luma specifies the difference between the base 2 logarithm of the maximum dimension (width or height) in the luma samples of a luma codec block that can be partitioned using ternary partitioning and the base 2 logarithm of the minimum dimension (width or height) in the luma samples of a luma leaf block resulting from a quadtree partitioning of a CTU in a slice with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_max_tt_min_qt_intra_slice_luma shall be in the range of 0 to CtbLog2SizeY - MinQtLog2SizeIntraY, inclusive. When not present, the value of ph_log2_diff_max_tt_min_qt_intra_slice_luma is inferred to be equal to sps_log2_diff_max_tt_min_qt_intra_slice_luma.

[0288] ph_log2_diff_min_qt_min_cb_intra_slice_chroma specifies the difference between the base 2 logarithm of the minimum size among the luma samples of the chroma leaf blocks resulting from the quadtree partitioning of the chroma CTU with treeType equal to DUAL_TREE_CHROMA and the base 2 logarithm of the minimum decoded block size among the luma samples of the chroma CU with treeType equal to DUAL_TREE_CHROMA in the slice with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_min_qt_min_cb_intra_slice_chroma shall be in the range of 0 to CtbLog2SizeY-MinCbLog2SizeY, inclusive. When not present, the value of ph_log2_diff_min_qt_min_cb_intra_slice_chroma is inferred to be equal to sps_log2_diff_min_qt_min_cb_intra_slice_chroma.

[0289] ph_max_mtt_hierarchy_depth_intra_slice_chroma specifies the maximum hierarchy depth of chroma codec units resulting from multi-type tree partitioning of chroma quadtree leaves with treeType equal to DUAL_TREE_CHROMA in slices with slice_type equal to 2(I) associated with the PH. The value of ph_max_mtt_hierarchy_depth_intra_slice_chroma shall be in the range of 0 to 2*(CtbLog2SizeY-MinCbLog2SizeY), inclusive. When not present, the value of ph_max_mtt_hierarchy_depth_intra_slice_chroma is inferred to be equal to sps_max_mtt_hierarchy_depth_intra_slice_chroma.

[0290] ph_log2_diff_max_bt_min_qt_intra_slice_chroma specifies the difference between the base 2 logarithm of the maximum dimension (width or height) in the luma samples of a chroma codec block that can be partitioned using binary partitioning and the base 2 logarithm of the minimum dimension (width or height) in the luma samples of a chroma leaf block resulting from a quadtree partitioning of a chroma CTU with treeType equal to DUAL_TREE_CHROMA in a slice with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_max_bt_min_qt_intra_slice_chroma shall be in the range of 0 to CtbLog2SizeY - MinQtLog2SizeIntraC, inclusive. When not present, the value of ph_log2_diff_max_bt_min_qt_intra_slice_chroma is inferred to be equal to sps_log2_diff_max_bt_min_qt_intra_slice_chroma.

[0291] ph_log2_diff_max_tt_min_qt_intra_slice_chroma specifies the difference between the base 2 logarithm of the maximum dimension (width or height) in the luma samples of a chroma codec block that can be partitioned using ternary partitioning and the base 2 logarithm of the minimum dimension (width or height) in the luma samples of a chroma leaf block resulting from a quadtree partitioning of a chroma CTU with treeType equal to DUAL_TREE_CHROMA in a slice with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_max_tt_min_qt_intra_slice_chroma shall be in the range of 0 to CtbLog2SizeY - MinQtLog2SizeIntraC, inclusive. When not present, the value of ph_log2_diff_max_tt_min_qt_intra_slice_chroma is inferred to be equal to sps_log2_diff_max_tt_min_qt_intra_slice_chroma.

[0292] ph_cu_qp_delta_subdiv_intra_slice specifies the maximum cbSubdiv value for codec units in intra slices that convey cu_qp_delta_abs and cu_qp_delta_sign_flag. The value of ph_cu_qp_delta_subdiv_intra_slice shall be in the range of 0 to 2*(CtbLog2SizeY - MinQtLog2SizeIntraY + ph_max_mtt_hierarchy_depth_intra_slice_luma), inclusive.

[0293] When not present, the value of ph_cu_qp_delta_subdiv_intra_slice is inferred to be equal to 0.

[0294] ph_cu_chroma_qp_offset_subdiv_intra_slice specifies the maximum cbSubdiv value for codec units in intra slices that transmit cu_chroma_qp_offset_flag. The value of ph_cu_chroma_qp_offset_subdiv_intra_slice shall be in the range of 0 to 2*(CtbLog2SizeY - MinQtLog2SizeIntraY + ph_max_mtt_hierarchy_depth_intra_slice_luma), inclusive.

[0295] When not present, the value of ph_cu_chroma_qp_offset_subdiv_intra_slice is inferred to be equal to 0.

[0296] ph_log2_diff_min_qt_min_cb_inter_slice specifies the difference between the base 2 logarithm of the minimum size of luma samples of luma leaf blocks resulting from quadtree partitioning of a CTU and the base 2 logarithm of the minimum luma codec block size in luma samples of luma CUs in slices with slice_type equal to 0 (B) or 1 (P) associated with the PH. The value of ph_log2_diff_min_qt_min_cb_inter_slice shall be in the range of 0 to CtbLog2SizeY-MinCbLog2SizeY, inclusive. When not present, the value of ph_log2_diff_min_qt_min_cb_luma is inferred to be equal to sps_log2_diff_min_qt_min_cb_inter_slice.

[0297] ph_max_mtt_hierarchy_depth_inter_slice specifies the maximum hierarchy depth of a codec unit resulting from a multi-type tree partitioning of quadtree leaves in slices with slice_type equal to 0 (B) or 1 (P) associated with the PH. The value of ph_max_mtt_hierarchy_depth_inter_slice shall be in the range of 0 to 2*(CtbLog2SizeY - MinCbLog2SizeY), inclusive. When not present, the value of ph_max_mtt_hierarchy_depth_inter_slice is inferred to be equal to sps_max_mtt_hierarchy_depth_inter_slice.

[0298] ph_log2_diff_max_bt_min_qt_inter_slice specifies the difference between the base 2 logarithm of the maximum dimension (width or height) in the luma samples of a luma codec block that can be partitioned using binary partitioning and the base 2 logarithm of the minimum dimension (width or height) in the luma samples of luma leaf blocks resulting from quadtree partitioning of CTUs in slices with slice_type equal to 0 (B) or 1 (P) associated with the PH. The value of ph_log2_diff_max_bt_min_qt_inter_slice shall be in the range of 0 to CtbLog2SizeY - MinQtLog2SizeInterY, inclusive. When not present, the value of ph_log2_diff_max_bt_min_qt_inter_slice is inferred to be equal to sps_log2_diff_max_bt_min_qt_inter_slice.

[0299] ph_log2_diff_max_tt_min_qt_inter_slice specifies the difference between the base 2 logarithm of the maximum dimension (width or height) in the luma samples of a luma codec block that can be partitioned using ternary partitioning and the base 2 logarithm of the minimum dimension (width or height) in the luma samples of luma leaf blocks resulting from a quadtree partitioning of a CTU in a slice with slice_type equal to 0 (B) or 1 (P) associated with the PH. The value of ph_log2_diff_max_tt_min_qt_inter_slice shall be in the range of 0 to CtbLog2SizeY - MinQtLog2SizeInterY, inclusive. When not present, the value of ph_log2_diff_max_tt_min_qt_inter_slice is inferred to be equal to sps_log2_diff_max_tt_min_qt_inter_slice.

[0300] ph_cu_qp_delta_subdiv_inter_slice specifies the maximum cbSubdiv value of the codec unit that transmits cu_qp_delta_abs and cu_qp_delta_sign_flag in inter slices. The value of ph_cu_qp_delta_subdiv_inter_slice shall be in the range of 0 to 2*(CtbLog2SizeY - MinQtLog2SizeInterY + ph_max_mtt_hierarchy_depth_inter_slice), inclusive.

[0301] When not present, the value of ph_cu_qp_delta_subdiv_inter_slice is inferred to be equal to 0.

[0302] ph_cu_chroma_qp_offset_subdiv_inter_slice specifies the maximum cbSubdiv value of the codec unit that transmits cu_chroma_qp_offset_flag in inter slices. The value of ph_cu_chroma_qp_offset_subdiv_inter_slice shall be in the range of 0 to 2*(CtbLog2SizeY - MinQtLog2SizeInterY + ph_max_mtt_hierarchy_depth_inter_slice), inclusive.

[0303] When not present, the value of ph_cu_chroma_qp_offset_subdiv_inter_slice is inferred to be equal to 0.

[0304] ph_temporal_mvp_enabled_flag specifies whether the temporal motion vector predictor can be used for inter prediction of the slices associated with the PH. If ph_temporal_mvp_enabled_flag is equal to 0, the syntax elements of the slices associated with the PH shall be constrained so that the temporal motion vector predictor is not used in the decoding of the slices. Otherwise (ph_temporal_mvp_enabled_flag is equal to 1), the temporal motion vector predictor can be used for decoding the slices associated with the PH. When not present, the value of ph_temporal_mvp_enabled_flag is inferred to be equal to 0. The value of ph_temporal_mvp_enabled_flag should be equal to 0 when no reference picture in the DPB has the same spatial resolution as the current picture.

[0305] The maximum number of sub-block-based merge MVP candidates, MaxNumSubblockMergeCand, is derived as follows:

[0306]

[0307] The value of MaxNumSubblockMergeCand should be in the range of 0 to 5 (inclusive).

[0308] ph_collocated_from_l0_flag equal to 1 specifies that the collocated picture used for temporal motion vector prediction is derived from reference picture list 0. ph_collocated_from_l0_flag equal to 0 specifies that the collocated picture used for temporal motion vector prediction is derived from reference picture list 1.

[0309] ph_collocated_ref_idx specifies the reference index of the collocated picture used for temporal motion vector prediction.

[0310] When ph_collocated_from_l0_flag is equal to 1, ph_collocated_ref_idx refers to the entry in reference picture list 0, and the value of ph_collocated_ref_idx shall be in the range of 0 to num_ref_entries[0][RplsIdx[0]]−1 (inclusive).

[0311] When ph_collocated_from_l0_flag is equal to 0, ph_collocated_ref_idx refers to an entry in reference picture list 1, and the value of ph_collocated_ref_idx shall be in the range of 0 to num_ref_entries[1][RplsIdx[1]]-1 (inclusive).

[0312] When not present, the value of ph_collocated_ref_idx is inferred to be equal to 0.

[0313] mvd_l1_zero_flag equal to 1 indicates that the mvd_coding(x0,y0,1) syntax structure is not parsed and for compIdx=0..1 and cpIdx=0..2, MvdL1[x0][y0][compIdx] and MvdCpL1[x0][y0][cpIdx][compIdx] are set equal to 0. mvd_l1_zero_flag equal to 0 indicates that the mvd_coding(x0,y0,1) syntax structure is parsed.

[0314] ph_fpel_mmvd_enabled_flag equal to 1 specifies that merge mode with motion vector differences uses integer sample precision in slices associated with PH. ph_fpel_mmvd_enabled_flag equal to 0 specifies that merge mode with motion vector differences may use fractional sample precision in slices associated with PH. When not present, the value of ph_fpel_mmvd_enabled_flag is inferred to be 0.

[0315] ph_disable_bdof_flag equal to 1 specifies that inter-frame bi-directional prediction based on bidirectional optical flow inter-frame prediction is disabled in the slice associated with PH. ph_disable_bdof_flag equal to 0 specifies that inter-frame bi-directional prediction based on bidirectional optical flow inter-frame prediction may be enabled or not enabled in the slice associated with PH.

[0316] When ph_disable_bdof_flag is not present, the following applies:

[0317] --If sps_bdof_enabled_flag is equal to 1, the value of ph_disable_bdof_flag is inferred to be equal to 0.

[0318] --Otherwise (sps_bdof_enabled_flag is equal to 0), the value of ph_disable_bdof_flag is inferred to be equal to 1.

[0319] ph_disable_dmvr_flag equal to 1 specifies that inter bi-prediction based on decoder motion vector refinement is disabled in slices associated with the PH. ph_disable_dmvr_flag equal to 0 specifies that inter bi-prediction based on decoder motion vector refinement may or may not be enabled in slices associated with the PH.

[0320] When ph_disable_dmvr_flag is not present, the following applies:

[0321] --If sps_dmvr_enabled_flag is equal to 1, the value of ph_disable_dmvr_flag is inferred to be equal to 0.

[0322] --Otherwise (sps_dmvr_enabled_flag is equal to 0), the value of ph_disable_dmvr_flag is inferred to be equal to 1.

[0323] ph_disable_prof_flag equal to 1 specifies that prediction refinement of optical flow is disabled in slices associated with PH. ph_disable_prof_flag equal to 0 specifies that prediction refinement of optical flow may be enabled or not enabled in slices associated with PH.

[0324] When ph_disable_prof_flag is not present, the following applies:

[0325] --If sps_affine_prof_enabled_flag is equal to 1, the value of ph_disable_prof_flag is inferred to be equal to 0.

[0326] --Otherwise (sps_affine_prof_enabled_flag is equal to 0), the value of ph_disable_prof_flag is inferred to be equal to 1.

[0327] ph_qp_delta specifies the Qp used for the codec blocks in the picture Y The initial value of until it is modified by the value of CuQpDeltaVal in the codec unit layer.

[0328] When qp_delta_info_in_ph_flag is equal to 1, the Qp of all slices of the picture Y The initial value of the quantization parameter SliceQp Y is exported as follows:

[0329] SliceQp Y=26+init_qp_minus26+ph_qp_delta (89)

[0330] SliceQp Y The value should be in the range of -QpBdOffset to +63 (inclusive).

[0331] ph_joint_cbcr_sign_flag specifies whether the co-located residual samples of the two chroma components have inverted signs in a transform unit for which tu_joint_cbcr_residual_flag[x0][y0] is equal to 1. When tu_joint_cbcr_residual_flag[x0][y0] is equal to 1 for a transform unit, ph_joint_cbcr_sign_flag equal to 0 specifies that the sign of each residual sample of the Cr (or Cb) component is the same as the sign of the co-located Cb (or Cr) residual sample, and ph_joint_cbcr_sign_flag equal to 1 specifies that the sign of each residual sample of the Cr (or Cb) component is given by the inverted sign of the co-located Cb (or Cr) residual sample.

[0332] ph_sao_luma_enabled_flag equal to 1 specifies that SAO is enabled for luma components in all slices associated with the PH; ph_sao_luma_enabled_flag equal to 0 specifies that SAO for luma components may be disabled for one, multiple, or all slices associated with the PH, and when ph_sao_luma_enabled_flag is not present, it is inferred to be equal to 0.

[0333] ph_sao_chroma_enabled_flag equal to 1 specifies that SAO is enabled for chroma components in all slices associated with the PH; ph_sao_chroma_enabled_flag equal to 0 specifies that SAO for chroma components may be disabled for one, multiple, or all slices associated with the PH. When ph_sao_chroma_enabled_flag is not present, it is inferred to be equal to 0.

[0334] ph_dep_quant_enabled_flag equal to 0 specifies that dependent quantization is disabled for the current picture. ph_dep_quant_enabled_flag equal to 1 specifies that dependent quantization is enabled for the current picture. When ph_dep_quant_enabled_flag is not present, it is inferred to be equal to 0.

[0335] pic_sign_data_hiding_enabled_flag equal to 0 specifies that sign bit hiding is disabled for the current picture. pic_sign_data_hiding_enabled_flag equal to 1 specifies that sign bit hiding is enabled for the current picture. When pic_sign_data_hiding_enabled_flag is not present, it is inferred to be equal to 0.

[0336] ph_deblocking_filter_override_flag equal to 1 specifies that deblocking parameters are present in PH. ph_deblocking_filter_override_flag equal to 0 specifies that deblocking parameters are not present in PH. When not present, the value of ph_deblocking_filter_override_flag is inferred to be equal to 0.

[0337] ph_deblocking_filter_disabled_flag equal to 1 specifies that the operation of the deblocking filter is not applicable to slices associated with the PH. ph_deblocking_filter_disabled_flag equal to 0 specifies that the operation of the deblocking filter is applicable to slices associated with the PH. When ph_deblocking_filter_disabled_flag is not present, it is inferred to be equal to pps_deblocking_filter_disabled_flag.

[0338] ph_beta_offset_div2 and ph_tc_offset_div2 specify the deblocking parameter offsets of beta and tc (divided by 2) that are applied to the luma component of the slice associated with the PH. The values ​​of ph_beta_offset_div2 and ph_tc_offset_div2 should both be in the range of -12 to 12, inclusive. When not present, the values ​​of ph_beta_offset_div2 and ph_tc_offset_div2 are inferred to be equal to pps_beta_offset_div2 and pps_tc_offset_div2, respectively.

[0339] ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2 specify the deblocking parameter offsets of β and tC (divided by 2) that are applied to the Cb component of the slice associated with the PH. The values ​​of ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2 should both be in the range -12 to 12, inclusive. When not present, the values ​​of ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2 are inferred to be equal to pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2, respectively.

[0340] ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2 specify the deblocking parameter offsets of β and tC (divided by 2) that are applied to the Cr component of the slice associated with the PH. The values ​​of ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2 should both be in the range of -12 to 12, inclusive. When not present, the values ​​of ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2 are inferred to be equal to pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2, respectively.

[0341] ph_extension_length specifies the length of the PH extension data in bytes, excluding the bits used to signal the ph_extension_length itself. The value of ph_extension_length shall be in the range of 0 to 256 (inclusive). When not present, the value of ph_extension_length is inferred to be equal to 0.

[0342] ph_extension_data_byte can have any value. Decoders conforming to this version of this specification shall ignore the value of ph_extension_data_byte. Its value does not affect the conformance of the decoder to the profile specified in this version of the specification.

[0343] SH Syntax and Semantics

[0344] In the latest VVC draft text, the SH syntax and semantics are as follows:

[0345]

[0346]

[0347]

[0348]

[0349]

[0350] The variable CuQpDeltaVal, which specifies the difference between the luma quantization parameter of the codec containing cu_qp_delta_abs and its prediction, is set equal to 0. The variable CuQpDeltaVal, which specifies the difference between the luma quantization parameter of the codec containing cu_qp_delta_abs and its prediction, is set equal to 0. Cb , Qp′ Cr and Qp′ CbCr The value of the variable CuQpOffset to use when the corresponding value of the quantization parameter Cb 、CuQpOffset Cr and CuQpOffset CbCr are all set equal to 0.

[0351] picture_header_in_slice_header_flag equal to 1 specifies that the PH syntax structure is present in the slice header. picture_header_in_slice_header_flag equal to 0 specifies that the PH syntax structure is not present in the slice header.

[0352] A bitstream conformance requirement is that the value of picture_header_in_slice_header_flag shall be the same in all codec slices in CLVS.

[0353] When picture_header_in_slice_header_flag is equal to 1 for a codec slice, the bitstream conformance requirement is that there shall be no VCL NAL units with nal_unit_type equal to PH_NUT in the CLVS.

[0354] When picture_header_in_slice_header_flag is equal to 0, all coded slices in the current picture shall have picture_header_in_slice_header_flag equal to 0, and the current PU shall have a PH NAL unit.

[0355] slice_subpic_id specifies the sub-picture ID of the sub-picture containing the slice. If slice_subpic_id exists, the value of the variable CurrSubpicIdx is derived such that SubpicIdVal[CurrSubpicIdx] is equal to slice_subpic_id. Otherwise (slice_subpic_id does not exist), CurrSubpicIdx is derived equal to 0. The length of slice_subpic_id is sps_subpic_id_len_minus1+1 bits.

[0356] slice_address specifies the slice address of the slice. When not present, the value of slice_address is inferred to be equal to 0. When rect_slice_flag is equal to 1 and NumSlicesInSubpic[CurrSubpicIdx] is equal to 1, the value of slice_address is inferred to be equal to 0.

[0357] If rect_slice_flag is equal to 0, the following applies:

[0358] --The stripe address is the raster scan stripe index.

[0359] --slice_address has a length of Ceil(Log2(NumTilesInPic)) bits.

[0360] The value of --slice_address should be in the range of 0 to NumTilesInPic–1 (inclusive).

[0361] Otherwise (rect_slice_flag is equal to 1), the following applies:

[0362] --The strip address is the sub-picture level strip index of the strip.

[0363] --The length of slice_address is Ceil(Log2(NumSlicesInSubpic[CurrSubpicIdx])) bits.

[0364] --slice_address values ​​should be in the range of 0 to NumSlicesInSubpic[CurrSubpicIdx]–1 (inclusive).

[0365] The requirement for bitstream conformance is that the following constraints apply:

[0366] --If rect_slice_flag is equal to 0 or subpic_info_present_flag is equal to 0, the value of slice_address shall not be equal to the value of slice_address of any other codec slice NAL unit of the same codec picture.

[0367] -- Otherwise, a pair of slice_subpic_id and slice_address values ​​shall not be equal to a pair of slice_subpic_id and slice_address values ​​of any other codec slice NAL unit of the same codec picture.

[0368] -- The shape of the slices of a picture shall be such that, when each CTU is decoded, its entire left and entire top borders shall consist of either the picture boundary or the boundaries of the previously decoded CTU(s).

[0369] sh_extra_bit[i] may be equal to 1 or 0. Decoders conforming to this version of this specification shall ignore the value of sh_extra_bit[i]. Its value does not affect the conformance of the decoder to the profile specified in this version of this specification.

[0370] num_tiles_in_slice_minus1 plus 1 (if present) specifies the number of tiles in a slice. The value of num_tiles_in_slice_minus1 should be in the range of 0 to NumTilesInPic–1, inclusive.

[0371] The variable NumCtusInCurrSlice specifies the number of CTUs in the current slice, and the list CtbAddrInCurrSlice[i], where i ranges from 0 to NumCtusInCurrSlice–1 (inclusive), specifies the picture raster scan address of the i-th CTB in the slice, derived as follows:

[0372]

[0373] The variables SubpicLeftBoundaryPos, SubpicTopBoundaryPos, SubpicRightBoundaryPos, and SubpicBotBoundaryPos are derived as follows:

[0374]

[0375] slice_type specifies the codec type of the slice according to Table 9.

[0376] Table 9 – Name associations with slice_type

[0377] slice_type The name of slice_type 0 B (B band) 1 P(P stripe) 2 I(I strip)

[0378] When not present, the value of slice_type is inferred to be equal to 2.

[0379] When ph_intra_slice_allowed_flag is equal to 0, the value of slice_type shall be equal to 0 or 1. When nal_unit_type is in the range of IDR_W_RADL to CRA_NUT (inclusive) and vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is equal to 1, slice_type shall be equal to 2.

[0380] The variables MinQtLog2SizeY, MinQtLog2SizeC, MinQtSizeY, MinQtSizeC, MaxBtSizeY, MaxBtSizeC, MinBtSizeY, MaxTtSizeY, MaxTtSizeC, MinTtSizeY, MaxMttDepthY and MaxMttDepthC are derived as follows:

[0381] --If slice_type is equal to 2 (I), the following applies:

[0382] MinQtLog2SizeY=

[0383] MinCbLog2SizeY+ph_log2_diff_min_qt_min_cb_intra_slice_luma (119)

[0384] MinQtLog2SizeC=

[0385] MinCbLog2SizeY+ph_log2_diff_min_qt_min_cb_intra_slice_chroma (120)

[0386] MaxBtSizeY=1<<

[0387] (MinQtLog2SizeY+ph_log2_diff_max_bt_min_qt_intra_slice_luma) (121)

[0388] MaxBtSizeC=1<<

[0389] (MinQtLog2SizeC + ph_log2_diff_max_bt_min_qt_intra_slice_chroma)(122)

[0390] MaxTtSizeY = 1 <<

[0391] (MinQtLog2SizeY + ph_log2_diff_max_tt_min_qt_intra_slice_luma)(123)

[0392] MaxTtSizeC = 1 <<

[0393] (MinQtLog2SizeC + ph_log2_diff_max_tt_min_qt_intra_slice_chroma)(124)

[0394] MaxMttDepthY = ph_max_mtt_hierarchy_depth_intra_slice_luma (125)

[0395] MaxMttDepthC = ph_max_mtt_hierarchy_depth_intra_slice_chroma (126)

[0396] CuQpDeltaSubdiv = ph_cu_qp_delta_subdiv_intra_slice (127)

[0397] CuChromaQpOffsetSubdiv = ph_cu_chroma_qp_offset_subdiv_intra_slice(128)

[0398] -- Otherwise (slice_type equals 0 (B) or 1 (P)), the following applies:

[0399] MinQtLog2SizeY = MinCbLog2SizeY + ph_log2_diff_min_qt_min_cb_inter_slice(129)

[0400] MinQtLog2SizeC = MinCbLog2SizeY + ph_log2_diff_min_qt_min_cb_inter_slice(130)

[0401] MaxBtSizeY = 1 <<

[0402] (MinQtLog2SizeY + ph_log2_diff_max_bt_min_qt_inter_slice) (131)

[0403] MaxBtSizeC = 1 <<

[0404] (MinQtLog2SizeC + ph_log2_diff_max_bt_min_qt_inter_slice) (132)

[0405] MaxTtSizeY = 1 <<

[0406] (MinQtLog2SizeY + ph_log2_diff_max_tt_min_qt_inter_slice) (133)

[0407] MaxTtSizeC = 1 <<

[0408] (MinQtLog2SizeC + ph_log2_diff_max_tt_min_qt_inter_slice) (134)

[0409] MaxMttDepthY = ph_max_mtt_hierarchy_depth_inter_slice (135)

[0410] MaxMttDepthC = ph_max_mtt_hierarchy_depth_inter_slice (136)

[0411] CuQpDeltaSubdiv = ph_cu_qp_delta_subdiv_inter_slice (137)

[0412] CuChromaQpOffsetSubdiv = ph_cu_chroma_qp_offset_subdiv_inter_slice(138)

[0413] -- The following applies:

[0414] MinQtSizeY = 1 << MinQtLog2SizeY (139)

[0415] MinQtSizeC = 1 << MinQtLog2SizeC (140)

[0416] MinBtSizeY=1< <MinCbLog2SizeY (141)

[0417] MinTtSizeY=1< <MinCbLog2SizeY (142)

[0418] slice_alf_enabled_flag equal to 1 specifies that the adaptive loop filter is enabled and can be applied to the Y, Cb or Cr color components in the slice. slice_alf_enabled_flag equal to 0 specifies that the adaptive loop filter is disabled for all color components in the slice. When not present, the value of slice_alf_enabled_flag is inferred to be equal to ph_alf_enabled_flag.

[0419] 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 is not present, the value of slice_num_alf_aps_ids_luma is inferred to be equal to the value of ph_num_alf_aps_ids_luma.

[0420] slice_alf_aps_id_luma[i] specifies the adaptation_parameter_set_id of the i-th ALF APS referenced by the luma component of the slice. The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i] shall be less than or equal to the TemporalId of the coded slice NAL unit. When slice_alf_enabled_flag is equal to 1 and slice_alf_aps_id_luma[i] is not present, the value of slice_alf_aps_id_luma[i] is inferred to be equal to the value of ph_alf_aps_id_luma[i].

[0421] The value of alf_luma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i].

[0422] slice_alf_chroma_idc equal to 0 specifies that the adaptive loop filter is not applied to the Cb and Cr color components. slice_alf_chroma_idc equal to 1 indicates that the adaptive loop filter is applied to the Cb color component. slice_alf_chroma_idc equal to 2 indicates that the adaptive loop filter is applied to the Cr color component. slice_alf_chroma_idc equal to 3 indicates that the adaptive loop filter is applied to the Cb and Cr color components. When slice_alf_chroma_idc is not present, it is inferred to be equal to ph_alf_chroma_idc.

[0423] 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 with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_chroma shall be less than or equal to the TemporalId of the codec slice NAL unit. When slice_alf_enabled_flag is equal to 1 and slice_alf_aps_id_chroma is not present, the value of slice_alf_aps_id_chroma is inferred to be equal to the value of ph_alf_aps_id_chroma.

[0424] The value of alf_chroma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_chroma.

[0425] slice_cc_alf_cb_enabled_flag equal to 0 specifies that the cross-component filter is not applied to the Cb color component. slice_cc_alf_cb_enabled_flag equal to 1 indicates that the cross-component filter is enabled and may be applied to the Cb color component. When slice_cc_alf_cb_enabled_flag is not present, it is inferred to be equal to ph_cc_alf_cb_enabled_flag.

[0426] slice_cc_alf_cb_aps_id specifies the adaptation_parameter_set_id referenced by the Cb color component of the slice.

[0427] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cb_aps_id shall be less than or equal to the TemporalId of the codec slice NAL unit. When slice_cc_alf_cb_enabled_flag is equal to 1 and slice_cc_alf_cb_aps_id is not present, the value of slice_cc_alf_cb_aps_id is inferred to be equal to the value of ph_cc_alf_cb_aps_id.

[0428] The value of alf_cc_cb_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cb_aps_id.

[0429] slice_cc_alf_cr_enabled_flag equal to 0 specifies that the cross-component filter is not applied to Cr color components. slice_cc_alf_cb_enabled_flag equal to 1 indicates that the cross-component adaptive loop filter is enabled and may be applied to Cr color components. When slice_cc_alf_cr_enabled_flag is not present, it is inferred to be equal to ph_cc_alf_cr_enabled_flag.

[0430] slice_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id referenced by the Cr color components of the slice. The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cr_aps_id shall be less than or equal to the TemporalId of the codec slice NAL unit. When slice_cc_alf_cr_enabled_flag is equal to 1 and slice_cc_alf_cr_aps_id is not present, the value of slice_cc_alf_cr_aps_id is inferred to be equal to the value of ph_cc_alf_cr_aps_id.

[0431] The value of alf_cc_cr_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cr_aps_id.

[0432] When separate_colour_plane_flag is equal to 1, colour_plane_id identifies the colour plane associated with the current slice. The value of colour_plane_id shall be in the range 0 to 2, inclusive. colour_plane_id values ​​0, 1 and 2 correspond to the Y, Cb and Cr planes respectively. The value 3 of colour_plane_id is reserved for future use by ITU-T | ISO / IEC.

[0433] NOTE 1 – There is no dependency between the decoding processes of different color planes of a picture.

[0434] num_ref_idx_active_override_flag equal to 1 specifies that the syntax element num_ref_idx_active_minus1[0] is present in P slices and B slices, and the syntax element num_ref_idx_active_minus1[1] is present in B slices. num_ref_idx_active_override_flag equal to 0 specifies that the syntax elements num_ref_idx_active_minus1[0] and num_ref_idx_active_minus1[1] are not present. When not present, the value of num_ref_idx_active_override_flag is inferred to be equal to 1.

[0435] num_ref_idx_active_minus1[i] is used to derive the variable NumRefIdxActive[i] as specified in Equation 143. The value of num_ref_idx_active_minus1[i] shall be in the range of 0 to 14 (inclusive).

[0436] For i equal to 0 or 1, when the current slice is a B slice, num_ref_idx_active_override_flag is equal to 1, and num_ref_idx_active_minus1[i] is not present, num_ref_idx_active_minus1[i] is inferred to be equal to 0.

[0437] When the current slice is a P slice, num_ref_idx_active_override_flag is equal to 1, and num_ref_idx_active_minus1[0] is not present, num_ref_idx_active_minus1[0] is inferred to be equal to 0.

[0438] The variable NumRefIdxActive[i] is derived as follows:

[0439]

[0440] The value of NumRefIdxActive[i]-1 specifies the maximum reference index of reference picture list i that can be used to decode the slice. When the value of NumRefIdxActive[i] is equal to 0, no reference index of reference picture list i is available for decoding the slice.

[0441] When the current slice is a P slice, the value of NumRefIdxActive[0] should be greater than 0.

[0442] When the current slice is a B slice, NumRefIdxActive[0] and NumRefIdxActive[1] should both be greater than 0.

[0443] cabac_init_flag specifies the method used to determine the initialization table used during the initialization of context variables. When cabac_init_flag is not present, it is inferred to be equal to 0.

[0444] slice_collocated_from_l0_flag equal to 1 specifies that the collocated picture used for temporal motion vector prediction is derived from reference picture list 0. slice_collocated_from_l0_flag equal to 0 specifies that the collocated picture used for temporal motion vector prediction is derived from reference picture list 1.

[0445] When slice_type is equal to B or P, ph_temporal_mvp_enabled_flag is equal to 1, and slice_collocated_from_l0_flag is not present, the following applies:

[0446] --If rpl_info_in_ph_flag is equal to 1, slice_collocated_from_l0_flag is inferred to be equal to ph_collocated_from_l0_flag.

[0447] --Otherwise (rpl_info_in_ph_flag is equal to 0 and slice_type is equal to P), the value of slice_collocated_from_l0_flag is inferred to be equal to 1.

[0448] slice_collocated_ref_idx specifies the reference index of the collocated picture used for temporal motion vector prediction.

[0449] When slice_type is equal to P or when slice_type is equal to B and slice_collocated_from_l0_flag is equal to 1, slice_collocated_ref_idx refers to the entry in reference picture list 0, and the value of slice_collocated_ref_idx shall be in the range of 0 to NumRefIdxActive[0]−1, inclusive.

[0450] When slice_type is equal to B and slice_collocated_from_l0_flag is equal to 0, slice_collocated_ref_idx refers to the entry in reference picture list 1, and the value of slice_collocated_ref_idx should be in the range of 0 to NumRefIdxActive[1]−1 (inclusive).

[0451] When slice_collocated_ref_idx is not present, the following applies:

[0452] --If rpl_info_in_ph_flag is equal to 1, the value of slice_collocated_ref_idx is inferred to be equal to ph_collocated_ref_idx.

[0453] --Otherwise (rpl_info_in_ph_flag is equal to 0), the value of slice_collocated_ref_idx is inferred to be equal to 0.

[0454] A bitstream conformance requirement is that the picture referenced by slice_collocated_ref_idx should be the same for all slices of a codec picture.

[0455] The bitstream conformance requirement is that the values ​​of pic_width_in_luma_samples and pic_height_in_luma_samples of the reference picture referred to by slice_collocated_ref_idx shall be equal to the values ​​of pic_width_in_luma_samples and pic_height_in_luma_samples of the current picture, respectively, and RprConstraintsActive[slice_collocated_from_l0_flag? 0:1][slice_collocated_ref_idx] shall be equal to 0.

[0456] slice_qp_delta specifies the Qp used for the codec blocks in the slice. Y The initial value of until it is modified by the value of CuQpDeltaVal in the codec unit layer.

[0457] When qp_delta_info_in_ph_flag is equal to 0, the Qp Y The initial value of the quantization parameter SliceQp Y is exported as follows:

[0458] SliceQp Y =26+init_qp_minus26+slice_qp_delta (144)

[0459] SliceQp Y The value should be in the range of -QpBdOffset to +63 (inclusive).

[0460] When any of the following conditions is true:

[0461] --The value of wp_info_in_ph_flag is equal to 1, the value of pps_weighted_pred_flag is equal to 1, and the value of slice_type is equal to P.

[0462] --The value of wp_info_in_ph_flag is equal to 1, the value of pps_weighted_bipred_flag is equal to 1, and the value of slice_type is equal to B.

[0463] The following applies:

[0464] --The value of NumRefIdxActive[0] shall be less than or equal to the value of NumWeightsL0.

[0465] – For each reference picture index RefPicList[0][i] where i is in the range 0 to NumRefIdxActive[0]-1 (inclusive), the luma weight, Cb weight, and Cr weight applied to the reference picture index are LumaWeightL0[i], ChromaWeightL0[0][i], and ChromaWeightL0[1][i], respectively.

[0466] When wp_info_in_ph_flag is equal to 1, pps_weighted_bipred_flag is equal to 1, and slice_type is equal to B, the following applies:

[0467] --The value of NumRefIdxActive[1] shall be less than or equal to the value of NumWeightsL1.

[0468] – For each reference picture index RefPicList[1][i] where i is in the range 0 to NumRefIdxActive[1]-1 (inclusive), the luma weight, Cb weight, and Cr weight applied to the reference picture index are LumaWeightL1[i], ChromaWeightL1[0][i], and ChromaWeightL1[1][i], respectively.

[0469] slice_cb_qp_offset specifies the time required to determine Qp′ CbThe value of the quantization parameter is the difference to be added to the value of pps_cb_qp_offset. The value of slice_cb_qp_offset shall be in the range -12 to +12, inclusive. When slice_cb_qp_offset is not present, it is inferred to be equal to 0. The value of pps_cb_qp_offset + slice_cb_qp_offset shall be in the range -12 to +12, inclusive.

[0470] slice_cr_qp_offset specifies the time to determine Qp′ Cr The difference to be added to the value of pps_cr_qp_offset when quantizing the parameter value. The value of slice_cr_qp_offset shall be in the range -12 to +12, inclusive. When slice_cr_qp_offset is not present, it is inferred to be equal to 0. The value of pps_cr_qp_offset + slice_cr_qp_offset shall be in the range -12 to +12, inclusive.

[0471] slice_join_cbcr_qp_offset specifies the offset in determining Qp′ CbCr The value of slice_joint_cbcr_qp_offset_value is the difference to be added to the value of pps_joint_cbcr_qp_offset_value. The value of slice_joint_cbcr_qp_offset shall be in the range of -12 to +12, inclusive. When slice_joint_cbcr_qp_offset is not present, it is inferred to be equal to 0. The value of pps_joint_cbcr_qp_offset_value+slice_joint_cbcr_qp_offset shall be in the range of -12 to +12, inclusive.

[0472] cu_chroma_qp_offset_enabled_flag equal to 1 specifies that cu_chroma_qp_offset_flag may be present in transform unit and palette codec syntax. cu_chroma_qp_offset_enabled_flag equal to 0 specifies that cu_chroma_qp_offset_flag is not present in transform unit or palette codec syntax. When not present, the value of cu_chroma_qp_offset_enabled_flag is inferred to be equal to 0.

[0473] slice_sao_luma_flag equal to 1 specifies that SAO is enabled for luma components in the current slice; slice_sao_luma_flag equal to 0 specifies that SAO is disabled for luma components in the current slice. When slice_sao_luma_flag is not present, it is inferred to be equal to ph_sao_luma_enabled_flag.

[0474] slice_sao_chroma_flag equal to 1 specifies that SAO is enabled for the chroma components in the current slice; slice_sao_chroma_flag equal to 0 specifies that SAO is disabled for the chroma components in the current slice. When slice_sao_chroma_flag is not present, it is inferred to be equal to ph_sao_chroma_enabled_flag.

[0475] slice_deblocking_filter_override_flag equal to 1 specifies that deblocking parameters are present in the slice header. slice_deblocking_filter_override_flag equal to 0 specifies that deblocking parameters are not present in the slice header. When not present, the value of slice_deblocking_filter_override_flag is inferred to be equal to ph_deblocking_filter_override_flag.

[0476] slice_deblocking_filter_disabled_flag equal to 1 specifies that the operation of the deblocking filter is not applied to the current slice. slice_deblocking_filter_disabled_flag equal to 0 specifies that the operation of the deblocking filter is applied to the current slice. When slice_deblocking_filter_disabled_flag is not present, it is inferred to be equal to ph_deblocking_filter_disabled_flag.

[0477] slice_beta_offset_div2 and slice_tc_offset_div2 specify the deblocking parameter offsets of beta and tc (divided by 2) applied to the luma component of the current slice. The values ​​of slice_beta_offset_div2 and slice_tc_offset_div2 shall both be in the range -12 to 12 (inclusive). When not present, the values ​​of slice_beta_offset_div2 and slice_tc_offset_div2 are inferred to be equal to ph_beta_offset_div2 and ph_tc_offset_div2, respectively.

[0478] slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify the deblocking parameter offsets of beta and tc (divided by 2) applied to the Cb component of the current slice. The values ​​of slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 shall both be in the range -12 to 12 (inclusive). When not present, the values ​​of slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 are inferred to be equal to ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2, respectively.

[0479] slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify the deblocking parameter offsets for beta and tc (divided by 2) applied to the Cr components of the current slice. The values ​​of slice_cr_beta_offset_div2 and slice_cr_tc_offset_div2 shall both be in the range -12 to 12, inclusive. When not present, the values ​​of slice_cr_beta_offset_div2 and slice_cr_tc_offset_div2 are inferred to be equal to ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2, respectively.

[0480] slice_ts_residual_coding_disabled_flag equal to 1 specifies that the residual_coding() syntax structure is used to parse the residual samples of the transform skipped blocks of the current slice. slice_ts_residual_coding_disabled_flag equal to 0 specifies that the residual_ts_coding() syntax structure is used to parse the residual samples of the transform skipped blocks of the current slice. When slice_ts_residual_coding_disabled_flag is not present, it is inferred to be equal to 0.

[0481] slice_lmcs_enabled_flag equal to 1 specifies that luma mapping with chroma scaling is enabled for the current slice. slice_lmcs_enabled_flag equal to 0 specifies that luma mapping with chroma scaling is not enabled for the current slice. When slice_lmcs_enabled_flag is not present, it is inferred to be equal to 0.

[0482] slice_scaling_list_present_flag equal to 1 specifies that the scaling list data for the current slice is derived based on the scaling list data contained in the reference scaling list APS, where aps_params_type is equal to SCALING_APS and adaptation_parameter_set_id is equal to ph_scaling_list_aps_id. slice_scaling_list_present_flag equal to 0 specifies that the scaling list data for the current picture is the default scaling list data specified in clause 7.4.3.21. When not present, the value of slice_scaling_list_present_flag is inferred to be equal to 0.

[0483] The variable NumEntryPoints specifies the number of entry points in the current strip and is derived as follows:

[0484]

[0485]

[0486] offset_len_minus1 plus 1 specifies the length in bits of the entry_point_offset_minus1[i] syntax element. The value of offset_len_minus1 shall be in the range of 0 to 31 (inclusive).

[0487] entry_point_offset_minus1[i] plus 1 specifies the i-th entry point offset in bytes and is represented by offset_len_minus1 plus 1 bit. The slice data following the slice header consists of NumEntryPoints+1 subsets, where the subset index values ​​range from 0 to NumEntryPoints (inclusive). The first byte of the slice data is considered to be byte 0. When present, the emulation prevention bytes appearing in the slice data portion of the codec slice NAL unit are counted as part of the slice data for subset identification purposes. Subset 0 consists of bytes 0 to entry_point_offset_minus1[0] (inclusive) of the codec slice data, and subset k (where k ranges from 1 to NumEntryPoints-1 (inclusive)) consists of bytes firstByte[k] to lastByte[k] (inclusive) of the codec slice data, where firstByte[k] and lastByte[k] are defined as:

[0488]

[0489] lastByte[k]=firstByte[k]+entry_point_offset_minus1[k] (147)

[0490] The last subset (where the subset index is equal to NumEntryPoints) consists of the remaining bytes of the encoded and decoded slice data.

[0491] When sps_entropy_coding_sync_enabled_flag is equal to 0 and a slice contains one or more complete slices, each subset shall consist of all codec bits of all CTUs in the slice within the same slice, and the number of subsets (i.e., the value of NumEntryPoints+1) shall be equal to the number of slices in the slice.

[0492] When sps_entropy_coding_sync_enabled_flag is equal to 0 and a slice contains a subset of CTU rows from a single slice, NumEntryPoints shall be 0 and the number of subsets shall be 1. The subset shall consist of all codec bits of all CTUs in the slice.

[0493] When sps_entropy_coding_sync_enabled_flag is equal to 1, each subset k in the range of 0 to NumEntryPoints (including the end value) shall consist of all codec bits of all CTUs in the CTU rows in the slice, and the number of subsets (i.e., the value of NumEntryPoints+1) shall be equal to the total number of slice-specific CTU rows in the slice.

[0494] slice_header_extension_length specifies the length of the slice header extension data in bytes, excluding the bits used to signal the slice_header_extension_length itself. The value of slice_header_extension_length shall be in the range of 0 to 256 (inclusive). When not present, the value of slice_header_extension_length is inferred to be equal to 0.

[0495] slice_header_extension_data_byte[i] can have any value. A decoder conforming to this version of this specification shall ignore the value of all slice_header_extension_data_byte[i] syntax elements. Its value does not affect the conformance of the decoder to the profile specified in this version of this specification.

[0496] 3.4. Inter-frame block decoding process - fractional sample interpolation process

[0497] In the latest VVC draft text, the decoding process of the fractional sample interpolation process is as follows:

[0498] Inputs to this process include:

[0499] – Luma position (xSb, ySb), specifies the top left sample of the current codec subblock relative to the top left luma sample of the current picture,

[0500] – The variable sbWidth specifies the width of the current codec sub-block.

[0501] – The variable sbHeight specifies the height of the current codec sub-block.

[0502] – motion vector offset mvOffset,

[0503] – The exact motion vector refMvLX,

[0504] – The selected reference picture sample array refPicLX,

[0505] – Half-sample interpolation filter index hpelIfIdx,

[0506] – decoder side motion vector refinement flag dmvrFlag,

[0507] – bidirectional optical flow flag bdofFlag,

[0508] – The variable refPicIsScaled indicates whether the selected reference picture needs to be scaled,

[0509] – The variable cIdx specifies the color component index of the current block.

[0510] – List of scalingRatios, horizontal and vertical.

[0511] The output of this process is:

[0512] – The (sbWidth+brdExtSize)x(sbHeight+brdExtSize) array of predicted sample values, predSamplesLX.

[0513] The prediction block boundary extension size brdExtSize is derived as follows:

[0514] brdExtSize=(bdofFlag||(inter_affine_flag[xSb][ySb]&&!ph_disable_prof_flag))? 2:0 (934)

[0515] The variable refWraparoundEnabledFlag is set equal to (pps_ref_wraparound_enabled_flag && !refPicIsScaled).

[0516] The variable fRefLeftOffset is set equal to ((SubWidthC*scaling_win_left_offset)<<10), where scaling_win_left_offset is the scaling_win_left_offset of the reference picture.

[0517] The variable fRefTopOffset is set equal to ((SubWidthC*scaling_win_top_offset)<<10), where scaling_win_top_offset is the scaling_win_top_offset of the reference picture.

[0518] The (sbWidth+brdExtSize)x(sbHeight+brdExtSize) array predSamplesLX of predicted sample values ​​is derived as follows:

[0519] – The motion vector mvLX is set to (refMvLX mvOffset).

[0520] – If cIdx is equal to 0, the following conditions apply:

[0521] –Let (xInt L ,yInt L ) is the brightness position given in units of full samples, and (xFrac L , L ) are offsets given in units of 1 / 16 sample. These variables are used only in this clause to specify fractional sample locations within the reference sample array refPicLX.

[0522] – The upper left coordinate of the boundary block filled with reference samples (xSbInt L ,ySbInt L ) is set equal to (xSb+(mvLX[0]>>4), ySb+(mvLX[1]>>4)).

[0523] – For each brightness sample position (x L =0..sbWidth-1+brdExtSize,y L =0..sbHeight-1+brdExtSize), then the corresponding predicted brightness sample value predSamplesLX[x L ][y L ] is exported as follows

[0524] –Assume (refxSb L , refySb L ) and (refx L , refy L ) is the luminance bit pointed to by the motion vector (refMvLX[0], refMvLX[1]) in units of 1 / 16 samples. L ,refx L 、refySb L and refy L The derivation is as follows:

[0525] sbX L=(((xSb-(SubWidthC*scaling_win_left_offset))<<4)+refMvLX[0])*scalingRatio[0] (935)

[0526] refx L =((Sign(refxSb L )*((Abs(refxSb L )+128)>>8)+x L *((scalingRatio[0]+8)>>4))+fRefLeftOffset+32)>>6 (936)

[0527] sb L =(((ySb-(SubWidthC*scaling_win_top_offset))<<4)+refMvLX[1])*scalingRatio[1] (937)

[0528] refy L =((Sign(refySb L )*((Abs(refySb L )+128)>>8)+yL*((scalingRatio[1]+8)>>4))+fRefTopOffset+32)>>6 (938)

[0529] – Variable xInt L ,yInt L 、xFrac L and yFrac L The derivation is as follows:

[0530] xInt L =refx L >>4 (939)

[0531] yInt L =refy L >>4 (940)

[0532] xFrac L =refx L &15 (941)

[0533] yFrac L =refy L &15 (942)

[0534] – Predicted brightness sample value predSamplesLX[x L][y L ] is derived as follows:

[0535] – If bdofFlag is equal to TRUE or (ph_disable_prof_flag is equal to FALSE and inter_affine_flag[xSb][ySb] is equal to TRUE), and one or more of the following conditions is TRUE, the predicted luma sample values ​​predSamplesLX[xSb][ySb] are derived by invoking the luma integer sample acquisition process specified in clause 8.5.6.3.3: L ][y L ], where (xInt L +(xFrac L >>3)-1, yInt L +(yFrac L >>3)-1, refPicLX and refWraparoundEnabledFlag as input.

[0536] –x L is equal to 0.

[0537] –x L Equal to sbWidth+1.

[0538] –y L is equal to 0.

[0539] –y L Equal to sbHeight+1.

[0540] – Otherwise, the predicted luma sample values ​​predSamplesLX[x L ][y L ], where (xIntL-(brdExtSize>0?1:0), yIntL-(brdExtSize>0?1:0)), (xFracL, yFracL), (xSbInt L ,ySbInt L ), refPicLX, hpelIfIdx, sbWidth, sbHeight, dmvrFlag, refWraparoundEnabledFlag, scalingRatio[0], scalingRatio[1] and (xSb, ySb) as input.

[0541] – Otherwise (cIdx is not equal to 0), the following applies:

[0542] – Let (xIntC, yIntC) be the chroma position given in units of full samples, and (xFracC, yFracC) be the offset given in units of 1 / 32 samples. These variables are used only in this clause to specify general fractional sample positions within the reference sample array refPicLX.

[0543] – The upper left coordinate (xSbIntC, ySbIntC) of the reference sample filled boundary block is set equal to ((xSb / SubWidthC)+(mvLX[0]>>5), (ySb / SubHeightC)+(mvLX[1]>>5)).

[0544] – For each chroma sample position (xC = 0..sbWidth-1, yC = 0..sbHeight-1) in the predicted chroma sample array predSamplesLX, the corresponding predicted chroma sample value predSamplesLX[xC][yC] is derived as follows:

[0545] –Assume (refxSb C , refySb C ) and (refx C , refy C ) is the chroma position pointed to by the motion vector (refMvLX[0], refMvLX[1]) given in units of 1 / 32 samples. The variable refxSb C 、refySb C ,refx C and refy C The derivation is as follows:

[0546] addX=sps_chroma_horizontal_collocated_flag? 0:8*(scalingRatio[0]-(1<<14)) (943)

[0547] addY=sps_chroma_vertical_collocated_flag? 0:8*(scalingRatio[1]-(1<<14)) (944)

[0548] sbX C =(((xSb-(SubWidthC*scaling_win_left_offset)) / SubWidthC<<5)+

[0549] refMvLX[0])*scalingRatio[0]+addX (945)

[0550] refx C = ((Sign(refxSb C ) * ((Abs(refxSb C ) + 256) >> 9)

[0551] + xC * ((scalingRatio[0] + 8) >> 4)) + fRefLeftOffset / SubWidthC + 16) >> 5 (946)

[0552] refySb C

[0553] = (((ySb - (SubWidthC * scaling_win_top_offset)) / SubHeightC << 5) + refMvLX[1]) * scalingRatio[1] + addY (947)

[0554] – refy C = ((Sign(refySb C ) * ((Abs(refySb C ) + 256) >> 9)

[0555] + yC * ((scalingRatio[1] + 8) >> 4)) + fRefTopOffset / SubHeightC + 16) >> 5 (948)

[0556] – variable xInt C 、yIntC、xFrac C and yFrac C are derived as follows:

[0557] xInt C = refx C >> 5 (949)

[0558] yInt C = refy C >> 5 (950)

[0559] xFrac C = refx C & 31 (951)

[0560] yFrac C = refy C & 31 (952)

[0561] – The predicted sample values ​​predSamplesLX[xC][yC] are obtained by invoking the procedure specified in clause 8.5.6.3.4 with (xIntC, yIntC), (xFracC, yFracC), (xSbIntC, ySbIntC), sbWidth, sbHeight, refPicLX, dmvrFlag, refWraparoundEnabledFlag, scalingRatio[0] and scalingRatio[1] as input.

[0562] NOTE – Unlike the process specified in clause 8.4.5.2.13, this process uses sps_chroma_vertical_collocated_flag and sps_chroma_horizontal_collocated_flag.

[0563] 4. Technical problems solved by the technical solutions and implementation examples

[0564] Existing deblocking, scaling and PROF designs have the following problems:

[0565] 1) Currently, there are some problems with the design logic of deblocking (DB) control in PPS, PH and SH syntax elements.

[0566] a. First, according to the current semantics of the PPS syntax element pps_deblocking_filter_disabled_flag, the SH syntax element slice_deblocking_filter_disabled_flag will be checked, which is used to specify whether the deblocking filter is applied to the slices of the reference PPS. However, in addition to slice_deblocking_filter_disabled_flag, the PH syntax element ph_deblocking_filter_disabled_flag should also be checked together with pps_deblocking_filter_disabled_flag. Therefore, the current semantics of pps_deblocking_filter_disabled_flag is incorrect.

[0567] b. Secondly, according to the current draft text, when the SH syntax element slice_deblocking_filter_override_flag is not present, it is inferred to be equal to ph_deblocking_filter_override_flag. However, in addition to implicit or explicit signaling in the PPS, according to dbf_info_in_ph_flag, deblocking parameters can only be signaled in the PH or SH, but not both. Therefore, when dbf_info_in_ph_flag is true, the intention is to allow signaling of override deblocking filter parameters in the PH. In this case, if the PH override flag is true and the SH override flag is not signaled, but is inferred to be equal to the PH override flag, the additional deblocking filter parameters will still be signaled in the SH, which conflicts with the intention.

[0568] c. Third, according to the current draft text, if the PPS syntax element deblocking_filter_override_enabled_flag is equal to 1 and pps_deblocking_filter_disabled_flag is equal to 1, then ph_deblocking_filter_disabled_flag or slice_deblocking_filter_disabled_flag can still be explicitly signaled to be equal to 1. However, this case means that deblocking is disabled in PPS and it will be overridden, but the overriding process does not change anything (e.g., deblocking remains disabled in PH / SH), but wastes bits for signaling.

[0569] d. Fourth, the current deblocking design logic allows deblocking to be enabled in PH / SH even if it is disabled in PPS. Such design logic is very different from the design logic of most other codec tools, such as ALF, SAO, LMCS, TMVP, WP, etc.

[0570] e.PPS DB disable flag (i.e., pps_deblocking_filter_disabled_flag) is signaled only when deblocking_filter_control_present_flag is equal to 1, and if the flag is not present, it is inferred to be equal to 0. That is, the intention is to enable DB by default. The two syntax elements (i.e., PPS DB disable flag and deblocking_filter_control_present_flag) are somewhat redundant. A better design is necessary.

[0571] 2) According to the latest VVC draft text, the size of the prediction block generated for PROF depends on whether it is affine AMVP or affine MERGE mode. Assuming that sbWidth and sbHeight are the width and height of the sub-block of the affine codec block, in the current text, according to the condition "inter_affine_flag[xSb][ySb]&&!ph_disable_prof_flag", when prof is applied to the affine AMVP block, the prediction block with extended samples (such as (sbWidth+2)x(sbHeight+2)) is used for PROF, however, when PROF is applied to the affine MERGE block, the prediction block of sbWidth x sbHeight is used for PROF. This design leads to different processing mechanisms between PROF with affine AMVP and PROF with affine MERGE.

[0572] a. In addition, an 8-tap interpolation filter is used to generate internal prediction samples within the sub-block of PROF, and integer samples other than the 8-tap filter are used to generate extended prediction samples outside the sub-block of PROF. However, according to the current text, there are no extended samples for PROF with affine MERGE, which leads to the difference between PROF with affine AMVP and PROF with affine MERGE.

[0573] 3) Currently, picture-level or slice-level luma qp increment is always signaled in PH or SH, not in both. While slice-level chroma qp offset is optionally signaled in SH, and there is no PH signaling of picture-level chroma qp offset. This design may be inconsistent / inefficient / inflexible.

[0574] 4) In the latest VVC draft text, the definition of the allowed value ranges of PH syntax elements related to deltaQP signaling (such as ph_cu_qp_delta_subdiv_intra_slice, ph_cu_qp_delta_subdiv_inter_slice, ph_cu_chroma_qp_offset_subdiv_intra_slice, and ph_cu_chroma_qp_offset_subdiv_inter_slice) may not be precise.

[0575] 5. List of examples of solutions and implementations

[0576] In order to solve the above problems and some other problems not mentioned, the methods outlined below are disclosed. These items should be considered as examples to explain the overall concept and should not be interpreted in a narrow way. In addition, these items can be applied alone or in combination in any way.

[0577] In the following discussion, DBF parameters may include DBF on / off control parameters and DBF filtering parameters (eg, an indication of a β (beta) / Tc offset, such as pps_beta_offset_div2).

[0578] In the following discussion, SH may be associated with PH, i.e., SH is associated with a slice in a picture associated with PH. SH may be associated with PPS, i.e., SH is associated with a slice in a picture associated with PPS. PH may be associated with PPS, i.e., PH is associated with a picture, which is associated with PPS.

[0579] In the following discussion, SPS may be associated with PPS, ie, PPS may refer to SPS.

[0580] 1. Regarding the design of deblocking control in PPS, PH and SH for solving the first problem, one or more of the following methods are disclosed, for example in the first group of embodiments:

[0581] a. In one example, whether the operation of the deblocking filter is applied to the slice of the reference PPS may depend on the deblocking on / off flag (eg, ph_deblocking_filter_disabled_flag) of the associated PH.

[0582] i. For example, whether the operation of the deblocking filter is applied to the slice of the reference PPS may depend on whether deblocking is disabled in the PPS (e.g., pps_deblocking_filter_disabled_flag is equal to 1) and whether deblocking is disabled at the picture level (e.g., ph_deblocking_filter_disabled_flag is equal to 1) and whether deblocking is disabled at the slice level (e.g., slice_deblocking_filter_disabled_flag is equal to 1).

[0583] ii. Alternatively, whether the operation of the deblocking filter is applied to the slices of the reference PPS may depend on whether deblocking is disabled in the PPS (eg, pps_deblocking_filter_disabled_flag is equal to 1) and whether deblocking override is disabled at the picture level and the slice level (eg, deblocking_filter_override_enabled_flag is equal to 0).

[0584] iii. Alternatively, whether the operation of the deblocking filter is applied to the slices of the reference PPS may depend only on whether deblocking is disabled in the PPS (eg, pps_deblocking_filter_disabled_flag is equal to 1).

[0585] b. In addition, when slice_deblocking_filter_override_flag is not present, the value of slice_deblocking_filter_override_flag can be independent of ph_deblocking_filter_override_flag (can be inferred to be a specific value, such as 0).

[0586] c. Furthermore, optionally, whether the PH syntax element ph_deblocking_filter_disabled_flag and / or the SH syntax element slice_deblocking_filter_disabled_flag is explicitly signaled or implicitly inferred may depend on the value of the PPS deblocking on / off flag, eg pps_deblocking_filter_disabled_flag.

[0587] d. It is proposed that if DBF is disabled at the first level (eg, in PPS), it is not allowed to be enabled at lower levels (eg, PH / SH).

[0588] i. For example, the presence of picture / slice level DBF on / off control parameters in PH / SH may depend directly on the value of the DBF on / off flag signaled in PPS (eg, pps_deblocking_filter_disabled_flag), rather than the value of the DBF override flag signaled in PH / SH.

[0589] 1) For example, when the PPS DBF on / off control parameters specify that deblocking is disabled for a slice of the reference PPS (pps_deblocking_filter_disabled_flag is equal to 1), the PH / SH DBF on / off control parameters may not be signaled.

[0590] ii. In addition, the presence of DBF on / off control parameters at PPS / PH / SH can be adjusted directly based on the DBF global control flag (e.g., deblocking_filter_control_present_flag in PPS), which specifies the presence of DBF on / off control parameters and DBF filter parameters in PPS, PH and SH.

[0591] 1) For example, when the DBF global control flag specifies that neither DBF on / off control parameters nor DBF filter parameters are signaled (deblocking_filter_control_present_flag is equal to 0), the PPS / PH / SH DBF on / off control parameters may not be signaled.

[0592] iii. In addition, when the PPS deblocking on / off flag is not present, it can be inferred to be equal to a specific value, such as 0 or 1.

[0593] iv. In addition, when the PH deblocking on / off flag does not exist, it can be inferred that it is equal to the value of the PPS deblocking on / off flag.

[0594] v. In addition, when the SH deblocking on / off flag is not present, it can be inferred that it is equal to the value of the PPS / PH deblocking on / off flag.

[0595] e. It is proposed that if DBF is enabled at a first level (eg, in PH), it can be disabled at a lower level (eg, SH).

[0596] i. For example, for multiple slices in a picture, some slices are allowed to use a deblocking filter while some slices are not allowed to use a deblocking filter.

[0597] ii. For example, the signaling notification of the DBF on / off control flag at the SH may depend on the timing of the PH DBF on / off control flag.

[0598] 1) For example, when DBF is enabled for the current picture, a slice-level DBF on / off control flag may be further signaled to specify whether the current slice uses a deblocking filter.

[0599] f. Signaling of the PPS syntax element "dbf_info_in_ph_flag" may be independent of other syntax elements, such as deblocking_filter_override_enabled_flag. The syntax element "dbf_info_in_ph_flag" specifies whether DBF on / off control parameters and / or DBF filter parameters are present in PH or SH.

[0600] i. Additionally, optionally, the signaling of the picture / slice level DBF on / off flag in PH / SH can be adjusted directly based on dbf_info_in_ph_flag and / or pps_deblocking_filter_enabled_flag instead of the PH / SH DBF override flag.

[0601] g. It is proposed that the DBF override flag in PPS / PH / SH is only used to override the DBF filter parameters, not the DBF on / off control parameters.

[0602] i. For example, first signaling the DBF on / off control flag, then signaling the DBF overlay flag, the condition is based on the DBF on / off control flag of the same level (eg, PPS / PH / SH).

[0603] 1) For example, picture / slice level DBF on / off control parameters can be signaled in PH / SH regardless of whether the PH / SH DBF coverage flag is equal to true.

[0604] 2) For example, picture / slice level DBF on / off control parameters may be signaled in PH / SH regardless of whether the PPS DBF coverage flag is equal to true.

[0605] 3) For example, the DBF coverage flag is conditionally signaled based on the DBF on / off control flag at the same level (eg, PPS / PH / SH).

[0606] a. For example, signaling of a PPS deblocking override enabled flag (eg, deblocking_filter_override_enabled_flag) may depend on whether deblocking is enabled in the PPS (eg, pps_deblocking_filter_disabled_flag in the PPS is equal to 0).

[0607] i. For example, when deblocking is disabled in PPS, the PPS syntax element deblocking_filter_override_enabled_flag is not signaled.

[0608] b. For example, signaling of a PH deblocking override flag (eg, ph_deblocking_filter_override_flag) may depend on whether deblocking is enabled in the PH (eg, ph_deblocking_filter_disabled_flag equals 0).

[0609] i. For example, when deblocking is disabled in PH, the PH syntax element ph_deblocking_filter_override_flag is not signaled.

[0610] c. For example, signaling of the SH deblocking override flag (eg, slice_deblocking_filter_override_flag) may depend on whether deblocking is enabled in the SH (eg, slice_deblocking_filter_disabled_flag equals 0).

[0611] i. For example, when deblocking is disabled in SH, the SH syntax element slice_deblocking_filter_override_flag is not signaled.

[0612] d. In addition, when the PPS / PH / SH deblocking cover flag does not exist, it can be inferred to be equal to a specific value (such as 0).

[0613] 4) For example, the signaling of DBF filter parameters may depend directly on the DBF coverage flag, rather than the DBF on / off control flag.

[0614] a. For example, the presence of DBF filter parameters in PH (e.g., ph_beta_offset_div2, ph_tc_offset_div2, ph_cb_beta_offset_div2, ph_cb_tc_offset_div2, ph_cr_beta_offset_div2, ph_cr_tc_offset_div2) can be directly adjusted based on the DBF override flag in PH (e.g., ph_deblocking_filter_override_flag) instead of the DBF on / off flag in PH (e.g., ph_deblocking_filter).

[0615] b. For example, the presence of DBF filter parameters in SH (e.g., slice_beta_offset_div2, slice_tc_offset_div2, slice_cb_beta_offset_div2, slice_cb_tc_offset_div2, slice_cr_beta_offset_div2, slice_cr_tc_offset_div2) can be directly adjusted based on the DBF override flag in SH (e.g., slice_deblocking_filter_override_flag) instead of the DBF on / off flag in SH (e.g., slice_deblocking_filter).

[0616] h. It is proposed that the DBF on / off control in PPS / PH / SH can rely on the DBF "enable" flag instead of the DBF "disable" flag.

[0617] i. For example, a DBF enable flag (eg, named pps_deblocking_filter_enabled_flag) may be signaled in the PPS to specify whether deblocking is enabled for slices that reference the PPS.

[0618] ii. For example, the PPS DBF enable flag may be signaled independently from other syntax elements such as the DBF global control flag (eg, deblocking_filter_control_present_flag in PPS).

[0619] iii. For example, if DBF is disabled at a higher level (e.g., PPS or PH), the signaling notification of the DBF enable flag at the lower level (e.g., PH and / or SH) is absent and is inferred to be equal to the value of the on / off control flag at the higher level (e.g., PPS / PH).

[0620] iv. For example, the DBF global control flag (eg, deblocking_filter_control_present_flag in PPS) may be used only to control the presence of the DBF coverage flag at PPS / PH / SH and the DBF filter parameters at PPS / PH / SH.

[0621] 1) For example, the DBF global control flag (eg, deblocking_filter_control_present_flag in PPS) is not used to control the presence of DBF on / off control parameters at PPS / PH / SH.

[0622] 2) For example, the DBF global control flag is signaled only when DBF is enabled in PPS (eg, pps_deblocking_filter_enabled_flag is equal to 1).

[0623] a. For example, when DBF is disabled at PPS (eg, pps_deblocking_filter_enabled_flag is equal to 0), the DBF global control flag is not signaled.

[0624] b. Additionally, when deblocking is disabled in the PPS, deblocking_filter_control_present_flag is inferred to be equal to 0.

[0625] 3) For example, the signaling of the DBF override enable / disable flag in the PPS (eg, deblocking_filter_override_enabled_falg in the PPS) can be directly adjusted based on the DBF global control flag in the PPS instead of the DBF on / off flag.

[0626] 4) For example, the signaling of PPS DBF parameters (such as increment and tc value) can be adjusted directly based on the DBF global control flag in PPS instead of the DBF on / off flag.

[0627] i. It is proposed to allow overwriting of DBF on / off control parameters or DBF filter parameters, but not both.

[0628] i. In one example, an overlay mechanism may be allowed at PPS / PH / SH.

[0629] ii. In one example, if only DBF on / off control parameters can be overridden at different levels (e.g., PPS / PH / SH), the following may further apply:

[0630] 1) If DBF is enabled for smaller video units, DBF filter parameters may be signaled only at the first level (eg, in the PPS), and all smaller video units (eg, pictures / slices) inherit the parameters associated with the first level.

[0631] iii. In one example, if only DBF filter parameters can be overridden at different levels (e.g., PPS / PH / SH), the following may further apply:

[0632] 1) If DBF is enabled for smaller video units, the DBF on / off control parameters may be signaled only at the first level (eg, in the PPS), and then all smaller video units (eg, pictures / slices) inherit the parameters associated with the first level.

[0633] j. It is proposed that when DBF is disabled at a higher level (eg, in PPS), overriding DBF on / off control parameters in smaller video units (eg, in PH / SH) is not allowed.

[0634] i. Optionally, furthermore, the signaling notification of the DBF on / off control parameter at a smaller video unit level (eg, in PH / SH) may be checked under the condition that the DBF on / off control parameter at a higher level (eg, in PPS) is turned on.

[0635] 1) Optionally, further, when not present at a smaller video unit level, DBF is inferred to be disabled or enabled at a higher video unit level, or equal to an on / off state.

[0636] k. In PPS, “deblocking_filter_control_present_flag” may be removed, and the first syntax element indicating enabling / disabling of DBF may be directly signaled instead of being controlled by “deblocking_filter_control_present_flag”.

[0637] i. Optionally, in addition, a second syntax element for informing whether overwriting of DBF filter parameters is allowed may be further signaled based on the first syntax element corresponding to enabling DBF.

[0638] 1) Alternatively, furthermore, the DBF filter parameters may be signaled according to a second syntax element informing about the allowed overlay.

[0639] 1. In PPS, “deblocking_filter_control_present_flag” may be removed, and the first syntax element telling whether overwriting DBF parameters is allowed may be directly signaled instead of being controlled by “deblocking_filter_control_present_flag”.

[0640] i. Alternatively, in addition, the second syntax element informing of enabling / disabling DBF may be further signaled according to the first syntax element corresponding to allowing overlay.

[0641] 1) Optionally, in addition, DBF filter parameters may be signaled according to a second syntax element informing that DBF is enabled.

[0642] m. The syntax element indicating whether the DBF on / off control flag and / or DBF parameters are signaled in the PH or SH (eg, dbf_info_in_ph_flag) may be signaled in the PH instead of the PPS.

[0643] n. In one example, DBF on / off control flag and / or DBF parameters may be signaled in PH and SH.

[0644] i. For example, the DBF on / off control flag and / or DBF parameters signaled in the SH may overwrite the DBF on / off control flag and / or DBF parameters signaled in the PH.

[0645] o. It is proposed that the DBF on / off control flag and / or DBF parameters can be signaled in the SPS.

[0646] i. The DBF on / off control flag signaled in SPS can be overwritten by the DBF on / off control flag signaled in lower-level video units (such as PPS, PH or SH).

[0647] ii. The DBF parameters signaled in the SPS may be overwritten by the DBF parameters signaled in lower level video units (such as PPS, PH or SH).

[0648] p. Syntax with non-binary values ​​(e.g., indicators other than flags) may be signaled at the video unit level (e.g., PPS / SPS) to specify a deblocking mode, for example, as in the first set of embodiments (such as the embodiments in Section 6.1.4 of this document). In one example, an N-bit mode indicator may be signaled at the PPS to specify a deblocking filter mode.

[0649] i. For example, N=2.

[0650] ii. For example, a 2-bit mode indicator (e.g., named deblocking_filter_mode_idc) is added to the PPS with the following semantics:

[0651] deblocking_filter_mode_idc equal to 0 specifies that the deblocking filter is not applied to all slices of the referenced PPS. deblocking_filter_mode_idc equal to 1 specifies that the deblocking filter is applied to all slices of the referenced PPS using deblocking parameter offsets of 0 for β and tC. deblocking_filter_mode_idc equal to 2 specifies that the deblocking filter is applied to all slices of the referenced PPS using deblocking parameter offsets of β and tC explicitly signaled in the PPS. deblocking_filter_mode_idc equal to 3 specifies that whether the deblocking filter is applied to the slices of the referenced PPS is controlled by parameters present in the PH of the slice or in the slice header.

[0652] iii. Furthermore, the signaling of the DBF filter parameters in the PPS depends on the value of the mode indicator.

[0653] a. For example, if the mode indicator meets a certain condition (eg, is greater than a certain value X, such as X=1), the DBF filter parameters are signaled in the PPS. Otherwise, the PPS DBF filter parameters are inferred to be zero.

[0654] iv. Furthermore, the signaling of the PPS syntax element "dbf_info_in_ph_flag" specifying whether the DBF on / off control parameters and / or DBF filter parameters are present in the PH or SH may depend on the value of the mode indicator.

[0655] a. For example, if the mode indicator satisfies a certain condition (eg, is equal to a certain value Y, such as Y=3), the PPS syntax element "dbf_info_in_ph_flag" is signaled.

[0656] i. Furthermore, if the PPS syntax element "dbf_info_in_ph_flag" is not signaled, it is inferred to be equal to a specific value (such as 0 or 1).

[0657] v. Furthermore, the signaling of DBF on / off control parameters and / or DBF filter parameters in the PH or SH may depend on the value of the mode indicator.

[0658] a. For example, if the mode indicator satisfies a certain condition (eg, is equal to a certain value Y, such as Y=3), the picture level DBF on / off control flag may be signaled in the PH.

[0659] b. For example, if the mode indicator satisfies a certain condition (eg, is equal to a certain value Y, such as Y=3), then the slice level DBF on / off control flag at the SH may be signaled in the SH.

[0660] q.DBF can be enabled at pic / slice level and use 0 value beta / tc offset for DBF parameters.

[0661] i. In one example, one or more syntax elements (e.g., named explicit_default_deblocking_params_flag) may be signaled in the PPS to specify whether the default DBF parameters have a β / tc offset of 0 or an explicitly signaled β / tc offset, and only in the latter case, the β / tc offset is explicitly signaled. The DBF parameters determined by the PPS and the default DBF parameters may or may not be overridden at the picture level or slice level.

[0662] ii. In one example, one or more syntax elements (e.g., named explicit_default_deblocking_params_flag) may be signaled at the video unit level (e.g., SPS / PPS / PH / SH) to specify whether to use a 0-value β / tc offset or to explicitly signal the β / tc offset, in which case the β / tc offset is explicitly signaled.

[0663] 2. Regarding the processing mechanism of PROF with affine AMVP and PROF with affine MERGE for solving the second problem, for example, as in the second set of embodiments, one or more of the following methods are disclosed:

[0664] a. For affine MERGE encoded blocks, PROF can still be applied, and the prediction block size corresponding to M*N sub-blocks (or blocks) can be larger than M*N, that is, represented by (M+M0)*(N+N0), where M0 and N0 are not both equal to 0.

[0665] i. In one example, M0 and N0 are set to 2.

[0666] b. Whether to use extended samples to generate a PROF prediction block (sub-block) and / or how many extended samples to generate for a PROF prediction block (sub-block) may depend on a prediction refinement utilization flag, such as cbProfFlagLX, where X is 0 or 1.

[0667] i. A specific value of the prediction block boundary extension size (eg, extended width and / or extended height and / or extended number of samples) may be used, regardless of whether it is a PROF sub-block with affine AMVP or a PROF sub-block with affine MERGE.

[0668] a) For example, for an M×N sub-block to which PROF is applied, where M is the sub-block width and N is the sub-block height, X (e.g., X=2) extended samples in width and Y (e.g., Y=2) extended samples in height may be used to construct (M+X)x(N+Y) prediction samples of the PROF sub-block, regardless of whether it is a PROF sub-block with affine AMVP or a PROF sub-block with affine MERGE.

[0669] ii. Integer samples are used to generate extended samples for PROF prediction, no matter it is a PROF sub-block with affine AMVP or a PROF sub-block with affine MERGE.

[0670] 3. Regarding PH and SH qp increment / offset signaling notification for solving the third problem, one or more of the following methods are disclosed:

[0671] a. In one example, the first syntax element may be signaled at a higher level compared to PH / SH (eg, SPS / PPS) to indicate whether luma / chroma delta QP signaling is enabled.

[0672] i. In one example, the presence of luma qp delta in PH and / or SH may depend on the SPS / PPS luma qp delta present flag (eg, pps_pic_slice_luma_qp_delta_present_flag), for example, as in the third embodiment.

[0673] a) For example, if the SPS / PPS luma qp increment presence flag specifies that neither the PH luma qp increment nor the SH luma qp increment is signaled, then it is required that neither the luma qp increment is signaled in the PH nor in the SH.

[0674] a. Optionally, if the SPS / PPS luma qp increment presence flag specifies that the PH / SH luma qp increment does not exist, it is required that the luma qp increment is not signaled in the PH / SH.

[0675] b. Additionally, if the PH brightness qp increment does not exist, it can be inferred to be a specific value (eg, 0).

[0676] c. Additionally, if the SH brightness qp increment does not exist, it can be inferred to be a specific value (eg, 0 or equal to the PH brightness qp increment).

[0677] b) Furthermore, the presence of a PPS switch flag (eg, qp_delta_info_in_ph_flag) that specifies whether the luma qp delta is signaled in the PH or SH may depend on the SPS / PPS luma qp delta present flag described above.

[0678] a. For example, if the SPS / PPS luma qp increment present flag specifies that neither the PH luma qp increment nor the SH luma qp increment is to be signaled, then the PPS switch flag is required not to be signaled.

[0679] i. Additionally, if the PPS switch flag is not present, it can be inferred to be equal to a specific value (eg, 0).

[0680] b. In one example, chroma (e.g., Cb, Cr, joint CbCr) qp offsets may be signaled at a higher level (e.g., in PH, e.g., as in the third embodiment) compared to SH.

[0681] i. For example, whether to signal the chroma qp offset in PH or SH may depend on the PPS switch flag (eg, qp_offset_info_in_ph_flag).

[0682] a) For example, if the PPS switch flag specifies that the chroma qp offset is signaled in the PH, the chroma qp offset is not signaled in the SH.

[0683] a. Optionally, if the PPS switch flag specifies that the chroma qp offset is not signaled in the PH, the chroma qp offset can be signaled in the SH.

[0684] b. Additionally, if the PH chroma qp offset does not exist, it can be inferred to be a specific value (eg, 0).

[0685] c. Additionally, if the SH chroma qp offset does not exist, it may be inferred to be a specific value (eg, 0 or equal to the PH chroma qp offset).

[0686] b) In one example, this flag is the same as the flag that controls whether the luma delta qp is signaled in PH or SH.

[0687] ii. Additionally, optionally, the presence of chroma qp offset in PH and / or SH may depend on the SPS / PPS chroma qp offset present flag (eg, pps_pic_slice_chroma_qp_offset_present_flag).

[0688] a) For example, if the SPS / PPS chroma qp offset present flag specifies that neither PH chroma qp offset nor SH chroma qp offset is signaled, then it is required that no chroma qp offset is signaled in PH and no chroma qp offset is signaled in SH.

[0689] b) Additionally, the presence of a PPS switch flag (eg, qp_offset_info_in_ph_flag) that specifies whether the chroma qp offset is signaled in the PH or SH may depend on the above-mentioned SPS / PPS chroma qp offset present flag.

[0690] a. If the SPS / PPS chroma qp offset present flag specifies that neither the PH chroma qp offset nor the SH chroma qp offset is signaled, then the PPS switch flag is required not to be signaled.

[0691] i. Additionally, if the PPS switch flag is not present, it can be inferred to be equal to a specific value (eg, 0).

[0692] iii. Signaling of qp_delta and chroma qp offset may always be in the same header.

[0693] a) For example, when qp_delta is signaled in PH, chroma qp offset should not be signaled in SH.

[0694] b) For example, when qp_delta is signaled in SH, chroma qp offset should not be signaled in PH.

[0695] 4. Regarding the ranges of the PH syntax elements ph_cu_qp_delta_subdiv_intra_slice, ph_cu_qp_delta_subdiv_inter_slice, ph_cu_chroma_qp_subdiv_intra_slice, and ph_cu_chroma_qp_offset_subdiv_inter_slice for solving the second problem, for example, as in the fourth embodiment, one or more of the following methods are disclosed:

[0696] a. The range of the maximum cbSubdiv value for a codec unit in an intra slice (e.g., ph_cu_qp_delta_subdiv_intra_slice) that transmits cu_qp_delta_abs and cu_qp_delta_sign_flag may not depend on ph_max_mtt_hierarchy_depth_intra_slice_luma, e.g., it may be in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY)+2*(CtbLog2SizeY-MinCbLog2SizeY) (inclusive)

[0697] i. Alternatively, it can be in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY)+2*min(ph_max_mtt_hierarchy_depth_intra_slice_luma,CtbLog2SizeY-MinCbLog2SizeY) (inclusive).

[0698] b. The range of maximum cbSubdiv values ​​for codec units in intra slices (e.g., ph_cu_chroma_qp_offset_subdiv_intra_slice) that transmit cu_chroma_qp_offset_flag may not depend on ph_max_mtt_hierarchy_depth_intra_slice_luma, e.g., it may be in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY)+2*(CtbLog2SizeY-MinCbLog2SizeY) (inclusive).

[0699] i. Alternatively, it can be in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY)+2*min(ph_max_mtt_hierarchy_depth_intra_slice_luma,CtbLog2SizeY-MinCbLog2SizeY) (inclusive).

[0700] c. The range of maximum cbSubdiv value for codec units transmitting inter slices (e.g., ph_cu_qp_delta_subdiv_inter_slice) that transmit cu_qp_delta_abs and cu_qp_delta_sign_flag may be independent of ph_max_mtt_hierarchy_depth_inter_slice, e.g., it may be in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeInterY)+2*(CtbLog2SizeY-MinCbLog2SizeY) (inclusive).

[0701] i. Alternatively, it can be in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY)+2*min(ph_max_mtt_hierarchy_depth_inter_slice,CtbLog2SizeY-MinCbLog2SizeY) (including the end values).

[0702] d. The range of maximum cbSubdiv value for codec units in inter slices (e.g., ph_cu_chroma_qp_offset_subdiv_inter_slice) that transmit cu_chroma_qp_offset_flag may be independent of ph_max_mtt_hierarchy_depth_inter_slice, e.g., it may be in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeInterY)+2*(CtbLog2SizeY-MinCbLog2SizeY) (inclusive).

[0703] i. Alternatively, it can be in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY)+2*min(ph_max_mtt_hierarchy_depth_inter_slice,CtbLog2SizeY-MinCbLog2SizeY) (including the end values).

[0704] 6. Examples

[0705] The following are some example embodiments of some aspects of the invention outlined in Section 5 above, which may be applied to the VVC specification. The changed text is based on the latest VVC text in JVET-Q2001-vD. Most of the relevant parts that have been added or modified are Highlighting, some deleted parts are highlighted with left and right double brackets (for example [[]]), and the deleted text is between the double brackets.

[0706] 6.1. The first set of examples

[0707] This is a set of embodiments of item 1 (1.a to 1.o) outlined in Section 5 above.

[0708] 6.1.1. Implementation of Item 1.a

[0709] In one example, the semantics of pps_deblocking_filter_disabled_flag changes as follows:

[0710] A value of 1 specifies that the deblocking filter operation should not be applied to references where slice_deblocking_filter_disabled_flag [[does not exist]] pps_deblocking_filter_disabled_flag equal to 0 specifies that the deblocking filter operation is applied to the reference slice_deblocking_filter_disabled_flag[[yes]] [[Not present]] The slice of the PPS. When not present, the value of pps_deblocking_filter_disabled_flag is inferred to be equal to 0.

[0711] 6.1.2. Example of Item 1.b

[0712] In one example, the semantics of slice_deblocking_filter_override_flag changes as follows:

[0713] slice_deblocking_filter_override_flag equal to 1 specifies that the deblocking parameters are present in the slice header. slice_deblocking_filter_override_flag equal to 0 specifies that the deblocking parameters are not present in the slice header. When not present, the value of slice_deblocking_filter_override_flag is inferred to be equal to [[ph_deblocking_filter_override_flag]]

[0714] 6.1.3. Example of Item 1.c

[0715] In one example, the syntax structure picture_header_structure() is changed as follows:

[0716]

[0717]

[0718] Equal to 1 specifies that the operation of the deblocking filter is not applied to the slices associated with the PH. ph_deblocking_filter_disabled_flag equal to 0 specifies that the operation of the deblocking filter is applied to the slices associated with the PH. When ph_deblocking_filter_disabled_flag does not exist , ph_deblocking_filter_disabled_flag is inferred to be equal to pps_deblocking_filter_disabled_flag.

[0719] And the syntax structure of slice_header() is changed as follows:

[0720]

[0721]

[0722] slice_deblocking_filter_override_flag is equal to 1 to specify that the deblocking parameters are present in the slice header. slice_deblocking_filter_override_flag is equal to 0 to specify that the deblocking parameters are not present in the slice header. When not present, the value of slice_deblocking_filter_override_flag is inferred to be equal to [[ph_deblocking_filter_override_flag]]

[0723] equal to 1 specifies that the deblocking filter operation is not applied to the current slice. slice_deblocking_filter_disabled_flag equal to 0 specifies that the deblocking filter operation is applied to the current slice. When slice_deblocking_filter_disabled_flag does not exist slice_deblocking_filter_disabled_flag is inferred to be equal to ph_deblocking_filter_disabled_flag.

[0724] 6.1.4. Implementation of Item 1.p

[0725] In one example, the syntax structure pic_parameter_set_rbsp() is changed as follows:

[0726]

[0727] ...

[0729]

[0730] [[deblocking_filter_control_present_flag equal to 1 specifies the presence of a deblocking filter control syntax element in the PPS. deblocking_filter_control_present_flag equal to 0 specifies the absence of a deblocking filter control syntax element in the PPS. ]]

[0731] equal to 1 specifies that ph_deblocking_filter_override_flag is present in the PH of the referenced PPS, or slice_deblocking_filter_override_flag is present in the slice header of the referenced PPS. deblocking_filter_override_enabled_flag equal to 0 specifies that ph_deblocking_filter_override_flag is not present in the PH of the referenced PPS, or slice_deblocking_filter_override_flag is not present in the slice header of the referenced PPS. When not present, the value of deblocking_filter_override_enabled_flag is inferred to be equal to 0. ]]

[0732] equal to 1 specifies that the operation of the deblocking filter is not applied to slices referencing a PPS for which slice_deblocking_filter_disabled_flag is not present. pps_deblocking_filter_disabled_flag equal to 0 specifies that the operation of the deblocking filter is applied to slices referencing a PPS for which slice_deblocking_filter_disabled_flag is not present. When not present, the value of pps_deblocking_filter_disabled_flag is inferred to be equal to 0. ]]

[0733] dbf_info_in_ph_flag is equal to 1 to specify that the deblocking filter information is present in the PH syntax structure and may not be present in the slice headers referencing a PPS that does not contain a PH syntax structure. dbf_info_in_ph_flag is equal to 0 to specify that the deblocking filter information is not present in the PH syntax structure and may be present in the slice headers referencing a PPS that does not contain a PH syntax structure. [[When not present, the value of dbf_info_in_ph_flag is inferred to be equal to 0. ]] ...

[0735] And the syntax structure picture_header_structure() is changed as follows:

[0736]

[0737] ...

[0739]

[0740] Equal to 1 specifies that the deblocking parameters exist in PH, ph_deblocking_[[filter]] _override_flag equal to 0 specifies that deblocking parameters are not present in PH. [[When not present, the value of ph_deblocking_filter_override_flag is inferred to be equal to 0. ]]

[0741] equal to 1 specifies that the operation of the deblocking filter is not applied to the slices associated with the PH. ph_deblocking_filter_disabled_flag equal to 0 specifies that the operation of the deblocking filter is applied to the slices associated with the PH. When ph_deblocking_filter_disabled_flag is not present, it is inferred to be equal to pps_deblocking_filter_disabled_flag. ]] ...

[0743] And the syntax structure of slice_header() is changed as follows:

[0744]

[0745] ...

[0747]

[0748] A value of 1 specifies that the deblocking parameters are present in the slice header. slice_deblocking_[[filter]] _override_flag equal to 0 specifies that deblocking parameters are not present in the slice header. [[When not present, the value of slice_deblocking_filter_override_flag is inferred to be equal to ph_deblocking_filter_override_flag. ]]

[0749] equal to 1 specifies that the deblocking filter operation is not applied to the current slice. slice_deblocking_filter_disabled_flag equal to 0 specifies that the deblocking filter operation is applied to the current slice. When slice_deblocking_filter_disabled_flag is not present, it is inferred to be equal to ph_deblocking_filter_disabled_flag. ]] ...

[0751] And the decoding process of the deblocking filtering process changes as follows:

[0752] 8.8.3 Deblocking Filtering Process

[0753] 8.8.3.1 General

[0754] The deblocking filter process is applied to all codec sub-block edges and transform block edges of the picture, except for the following types of edges:

[0755] – edges on the borders of the image,

[0756] – with subpic index subpicIdx and loop_filter_across_subpic_enabled_

[0757] The edge of the sub-picture whose borders overlap when flag[subpicIdx] is equal to 0,

[0758] – edges that coincide with the virtual boundaries of the picture when VirtualBoundariesPresentFlag is equal to 1, – edges that coincide with the tile boundaries when loop_filter_cross_tiles_enabled_flag is equal to 0, – edges that coincide with the strip boundaries when loop_filter_cross_slices_enabled_flag is equal to 0, – edges that coincide with the slice boundaries when slice_deblocking_filter_ [[disabled]]_flag is equal to [[1]] The upper or left border of the strip coincides with the edge,

[0759] –slice_deblocking_filter_ [[disabled]]_flag is equal to [[1]] The edge of the strip,

[0760] – edges that do not correspond to the boundaries of the 4×4 sample grid of the luma component,

[0761] – edges that do not correspond to the boundaries of the 8×8 sample grid of the chroma components,

[0762] – edges with intra_bdpcm_luma_flag equal to 1 on both sides of the edge in the luma component,

[0763] – edges with intra_bdpcm_chroma_flag equal to 1 on both sides of the edge in the chroma components,

[0764] – Edges of chroma sub-blocks that are not edges of the associated transform unit.

[0765] The vertical or horizontal edge type is indicated by the variable edge type as specified in Table 42.

[0766] Table 42 – Names associated with edgeType

[0767]

[0768] When the slice_deblocking_filter_ [[disabled]]_flag is equal to [[0]] The following apply:

[0769] –The variable treeType is set equal to DUAL_TREE_LUMA.

[0770] – Vertical edges are filtered by invoking a directional deblocking filter process as specified in clause 8.8.3.2, where the variables treeType, the reconstructed picture before deblocking (i.e., the array recPicture L ) and the variable edgeType set equal to EDGE_VER as input, the modified reconstructed picture after deblocking (i.e., the array recPicture L ) as output.

[0771] – Horizontal edges are filtered by invoking a directional deblocking filter process as specified in clause 8.8.3.2, where the variables treeType, the modified reconstructed picture after deblocking (i.e. the array recPicture L ) and the variable edgeType set equal to EDGE_HOR as input, the modified reconstructed picture after deblocking (i.e. the array recPicture L ) as output.

[0772] – When ChromaArrayType is not equal to 0, the following applies:

[0773] – The variable treeType is set equal to DUAL_TREE_CHROMA

[0774] – Vertical edges are filtered by invoking a directional deblocking filter process as specified in clause 8.8.3.2, where the variables treeType, the reconstructed picture before deblocking (i.e., the array recPicture Cb and recPicture Cr ) and the variable edgeType set equal to EDGE_VER as input, the modified reconstructed picture after deblocking (ie, the array recPicture Cb and recPicture Cr ) as output.

[0775] – Horizontal edges are filtered by invoking a directional deblocking filter process as specified in clause 8.8.3.2, where the variables treeType, the modified reconstructed picture after deblocking (i.e., the array recPicture Cb and recPicture Cr ) and the variable edgeType set equal to EDGE_HOR as input, the modified reconstructed picture after deblocking (i.e., the array recPicture Cb and recPicture Cr ) as output.

[0776] 6.1.5. Examples of Items 1.d, 1.g, 1.j and 1.f

[0777] In one example, the syntax structure pic_parameter_set_rbsp() is changed as follows:

[0778]

[0779] equal to 1 specifies that ph_deblocking_filter_override_flag is present in the PH of the referenced PPS, or slice_deblocking_filter_override_flag is present in the slice header of the referenced PPS. deblocking_filter_override_enabled_flag equal to 0 specifies that ph_deblocking_filter_override_flag is not present in the PH of the referenced PPS, [[or]] slice_deblocking_filter_override_flag is missing in the slice header of the referenced PPS. When not present, the value of deblocking_filter_override_enabled_flag is inferred to be equal to 0.

[0780] Equal to 1 specifies that the operation of the deblocking filter is not applied to slices that reference [[where slice_deblocking_filter_disabled_flag is not present]] PPS. pps_deblocking_filter_disabled_flag equal to 0 specifies that the operation of the deblocking filter is applied to slices that reference [[where slice_deblocking_filter_disabled_flag is not present]] PPS. When not present, the value of pps_deblocking_filter_disabled_flag is inferred to be equal to 0.

[0781] And the syntax structure picture_header_structure() is changed as follows:

[0782]

[0783] And the syntax structure of slice_header() is changed as follows:

[0784]

[0785] slice_deblocking_filter_override_flag is equal to 1 to specify that the deblocking parameters are present in the slice header. slice_deblocking_filter_override_flag is equal to 0 to specify that the deblocking parameters are not present in the slice header. When not present, the value of slice_deblocking_filter_override_flag is inferred to be equal to [[ph_deblocking_filter_override_flag]]

[0786] 6.1.6. Another embodiment of Items 1.d, 1.g, 1.j, 1.e and 1.n

[0787] In one example, the syntax structure pic_parameter_set_rbsp() is changed as follows:

[0788]

[0789] equal to 1 specifies that ph_deblocking_filter_override_flag is present in the PH of the referenced PPS, or slice_deblocking_filter_override_flag is present in the slice header of the referenced PPS. deblocking_filter_override_enabled_flag equal to 0 specifies that ph_deblocking_filter_override_flag is not present in the PH of the referenced PPS, [[or]] slice_deblocking_filter_override_flag is not present in the slice header of the referenced PPS. When not present, the value of deblocking_filter_override_enabled_flag is inferred to be equal to 0.

[0790] pps_deblocking_filter_disabled_flag equal to 1 specifies that the operation of the deblocking filter is not applied to slices that reference [[where slice_deblocking_filter_disabled_flag is not present]] PPS. pps_deblocking_filter_disabled_flag equal to 0 specifies that the operation of the deblocking filter is applied to slices that reference [[where slice_deblocking_filter_disabled_flag is not present]] PPS. When not present, the value of pps_deblocking_filter_disabled_flag is inferred to be equal to 0.

[0791] And the syntax structure picture_header_structure() is changed as follows:

[0792]

[0793] And the syntax structure of slice_header() is changed as follows:

[0794]

[0795]

[0796] slice_deblocking_filter_override_flag is equal to 1 to specify that the deblocking parameters are present in the slice header. slice_deblocking_filter_override_flag is equal to 0 to specify that the deblocking parameters are not present in the slice header. When not present, the value of slice_deblocking_filter_override_flag is inferred to be equal to [[ph_deblocking_filter_override_flag]]

[0797] 6.1.7. Another embodiment of items 1.d, 1.g, 1.j, 1.f, 1.h and 1.k

[0798] In one example, the syntax structure pic_parameter_set_rbsp() is changed as follows:

[0799]

[0800]

[0801]

[0802] equal to 1 specifies the presence of the deblocking filter control syntax element in the PPS. deblocking_filter_control_present_flag equal to 0 specifies the absence of the deblocking filter control syntax element in the PPS.

[0803] equal to 1 specifies that the operation of the deblocking filter shall not be applied to slices referencing a PPS where slice_deblocking_filter_disabled_flag is not present. pps_deblocking_filter_disabled_flag equal to 0 specifies that the operation of the deblocking filter shall be applied to slices referencing a PPS where slice_deblocking_filter_disabled_flag is not present. When not present, the value of pps_deblocking_filter_disabled_flag is inferred to be equal to 0. ]]

[0804] And the syntax structure picture_header_structure() is changed as follows:

[0805]

[0806] Equals [[1]] Specifies that the deblocking filter operation should not be applied to the slice associated with PH, ph_deblocking_filter_[[disabled]] _flag equals [[0]] Specifies that the deblocking filter operation is applied to the slice associated with the PH when ph_deblocking_filter_[[disabled]] When _flag is not present, it is inferred to be equal to pps_deblocking_filter_[[disabled]] _flag.

[0807] And the syntax structure of slice_header() is changed as follows:

[0808]

[0809] slice_deblocking_filter_override_flag is equal to 1 to specify that the deblocking parameters are present in the slice header. slice_deblocking_filter_override_flag is equal to 0 to specify that the deblocking parameters are not present in the slice header. When not present, the value of slice_deblocking_filter_override_flag is inferred to be equal to [[ph_deblocking_filter_override_flag]]

[0810] Equals [[1]] Specifies that the deblocking filter operation is not applied to the current slice. slice_deblocking_filter_[[disabled]] _flag equals [[0]] Specifies the operation of applying the deblocking filter to the current slice. When slice_deblocking_filter_[[disabled]] When _flag is not present, it is inferred to be equal to [[PPS]] _deblocking_filter_[[disabled]] _flag.

[0811] 6.2. Second set of examples

[0812] This is a set of embodiments of items 2, 2.a and 2.b outlined in Section 5 above.

[0813] 8.5.6.3 Fractional Sample Interpolation Process

[0814] 8.5.6.3.1 General

[0815] The input to this process is:

[0816] – Luma position (xSb, ySb), specifies the top left sample of the current codec subblock relative to the top left luma sample of the current picture,

[0817] – The variable sbWidth specifies the width of the current codec sub-block,

[0818] – The variable sbHeight that specifies the height of the current codec sub-block,

[0819] – motion vector offset mvOffset,

[0820] – The exact motion vector refMvLX,

[0821] – The selected reference picture sample array refPicLX,

[0822] – Half-sample interpolation filter index hpelIfIdx,

[0823] –

[0824] – decoder side motion vector refinement flag dmvrFlag,

[0825] – bidirectional optical flow flag bdofFlag,

[0826] – a variable refPicIsScaled indicating whether the selected reference picture needs to be scaled,

[0827] – The variable cIdx that specifies the color component index of the current block,

[0828] – List of scalingRatios, horizontal and vertical.

[0829] The output of this process is:

[0830] – The (sbWidth+brdExtSize)x(sbHeight+brdExtSize) array of predicted sample values, predSamplesLX.

[0831] The prediction block boundary extension size brdExtSize is derived as follows:

[0832] brdExtSize=(bdofFlag||[[(inter_affine_flag[xSb][ySb]

[0833] &&! ph_disable_prof_flag)]] )? 2:0 (934)

[0834] The variable refWraparoundEnabledFlag is set equal to (pps_ref_wraparound_enabled_flag && !refPicIsScaled).

[0835] The variable fRefLeftOffset is set equal to ((SubWidthC*scaling_win_left_offset)<<10), where scaling_win_left_offset is the scaling_win_left_offset of the reference picture.

[0836] The variable fRefTopOffset is set equal to ((SubWidthC*scaling_win_top_offset)<<10), where scaling_win_top_offset is the scaling_win_top_offset of the reference picture.

[0837] The derivation of the (sbWidth+brdExtSize)x(sbHeight+brdExtSize) array predSamplesLX of predicted sample values ​​is as follows:

[0838] – The motion vector mvLX is set to (refMvLX-mvOffset).

[0839] – If cIdx is equal to 0, the following applies:

[0840] –Let (xInt L ,yInt L ) is the luminance position given in full sample units, and (xFrac L ,yFrac L ) is an offset given in 1 / 16 sample units. These variables are used only in this clause to specify fractional sample positions within the reference sample array refPicLX.

[0841] – The upper left coordinate of the boundary block filled with reference samples (xSbInt L ,ySbInt L ) is set equal to (xSb+(mvLX[0]>>4), ySb+(mvLX[1]>>4)).

[0842] – For each brightness sample position (x L=0..sb width-1+brdExtSize,y L =0..sbHeight-1+brdExtSize), then the corresponding predicted brightness sample value predSamplesLX[x L ][y L ] is derived as follows:

[0843] –Assume (refxSb L , refySb L ) and (refx L , refy L ) is the luminance position in units of 1 / 16 samples pointed to by the motion vector (refMvLX[0], refMvLX[1]). L ,refx L 、refySb L and refy L The derivation is as follows:

[0844] sbX L =(((xSb-(SubWidthC*scaling_win_left_offset))<<4)+refMvLX[0])*scalingRatio[0] (935)

[0845] refx L =((Sign(refxSb L )*((Abs(refxSb L )+128)>>8)+

[0846] x L *((scalingRatio[0]+8)>>4))+fRefLeftOffset+32)>>6 (936)

[0847] sb L =(((ySb-(SubWidthC*scaling_win_top_offset))<<4)+refMvLX[1])*scalingRatio[1] (937)

[0848] refy L =((Sign(refySb L )*((Abs(refySb L )+128)>>8)+yL*((scalingRatio[1]+8)>>4))+fRefTopOffset+32)>>6 (938)

[0849] –Variable xIn t L, yInt L 、xFrac L and yFrac L The derivation is as follows:

[0850] xInt L =refx L >>4 (939)

[0851] yInt L =refy L >>4 (940)

[0852] xFrac L =refx L &15 (941)

[0853] yFrac L =refy L &15 (942)

[0854] – Predicted brightness sample value predSamplesLX[x L ][y L ] is exported as follows:

[0855] – If bdofFlag is equal to TRUE or [[(ph_disable_prof_flag is equal to FALSE and inter_affine_flag[xSb][ySb]]] is equal to TRUE[[)]], and one or more of the following conditions are TRUE, the predicted luma sample values ​​predSamplesLX[x L ][y L ]

[0856] , where (xInt L +(xFrac L >>3)-1),yInt L +(yFrac L >>3)-1), refPicLX and refWraparoundEnabledFlag as input.

[0857] –x L is equal to 0.

[0858] –x L Equal to sbWidth+1.

[0859] –y L is equal to 0.

[0860] –y L Equal to sbHeight+1.

[0861] – Otherwise, the predicted luma sample values ​​predSamplesLX[xL][yL] are obtained by invoking the luma sample 8-tap interpolation filtering process specified in clause 8.5.6.3.2, where (xIntL-(brdExtSize>0?1:0), yIntL-(brdExtSize>0?1:0)), (xFracL, yFracL), (xSbInt L ,ySbInt L ), refPicLX, hpelIfIdx, sbWidth, sbHeight, dmvrFlag, refWraparoundEnabledFlag, scalingRatio[0], scalingRatio[1] and (xSb, ySb) are taken as input.

[0862] – Otherwise (cIdx is not equal to 0), the following applies:

[0863] …

[0864] 6.3. The third set of examples

[0865] This is a set of embodiments of items 3, 3.a, 3.b and 3.c outlined in Section 5 above.

[0866] 6.3.1. Implementation of Item 3.a

[0867] In one example, the syntax structure pic_parameter_set_rbsp() is changed as follows:

[0868]

[0869]

[0870] And the syntax structure picture_header_structure() is changed as follows:

[0871]

[0872] And the syntax structure of slice_header() is changed as follows:

[0873]

[0874] 6.3.2. Example of Item 3.b

[0875] In one example, the syntax structure pic_parameter_set_rbsp() is changed as follows:

[0876]

[0877]

[0878] Equal to 1 rule The slice_cb_qp_offset and slice_cr_qp_offset syntax elements are present in the associated slice header. pps_slice_chroma_qp_offsets_present_flag is equal to 0. The slice_cb_qp_offset and slice_cr_qp_offset syntax elements are not present in the associated slice header. When not present, the value of pps_slice_chroma_qp_offsets_present_flag is inferred to be equal to 0.

[0879]

[0880] And the syntax structure picture_header_structure() is changed as follows:

[0881]

[0882]

[0883] And the syntax structure of slice_header() is changed as follows:

[0884]

[0885] It is stipulated that in determining Qp' Cb The value of the quantization parameter is the difference to be added to the value of pps_cb_qp_offset. The value of slice_cb_qp_offset shall be in the range -12 to +12 (inclusive). When slice_cb_qp_offset is not present, it is inferred to be equal to [[0]] The value of pps_cb_qp_offset + slice_cb_qp_offset should be in the range of -12 to +12 (inclusive).

[0886] Specifies the difference to be added to the pps_cr_qp_offset value when determining the value of the Qp'Cr quantization parameter. The value of slice_cr_qp_offset shall be in the range -12 to +12 (inclusive). When slice_cr_qp_offset is not present, it is inferred to be equal to [[0]] The value of pps_Cr_qp_offset+slice_Cr_qp_offset should be in the range of -12 to +12 (inclusive).

[0887] It is stipulated that in determining Qp' CbCr The value of slice_joint_cbcr_qp_offset is the difference to be added to the value of pps_joint_cbcr_qp_offset_value. The value of slice_joint_cbcr_qp_offset shall be in the range of -12 to +12 (inclusive). When slice_joint_cbcr_qp_offset is not present, it is inferred to be equal to [[0]] The value of pps_joint_cbcr_qp_offset_value+slice_joint_cbcr_qp_offset should be in the range of -12 to +12 (including the end values).

[0888] 6.3.3. Example of Item 3.c

[0889] by Changes to text tags are based on JVET-Q2001-vE.

[0890]

[0891]

[0892] Equal to 1 rule The slice_cb_qp_offset and slice_cr_qp_offset syntax elements are present in the associated slice header. pps_slice_chroma_qp_offsets_present_flag is equal to 0. The slice_cb_qp_offset and slice_cr_qp_offset syntax elements are not present in the associated slice header. When not present, the value of pps_slice_chroma_qp_offsets_present_flag is inferred to be equal to 0.

[0893] Equal to 1 rule QP increment information Present in the PH syntax structure, but not in the slice header that references a PPS that does not contain a PH syntax structure. qp_delta_info_in_ph_flag equal to 0 specifies the QP delta Not present in the PH syntax structure, and may be present in a slice header that references a PPS that does not contain a PH syntax structure.

[0894]

[0895] It is stipulated that in determining Qp' Cb The value of the quantization parameter is the difference to be added to the value of pps_cb_qp_offset. The value of slice_cb_qp_offset shall be in the range -12 to +12 (inclusive). When slice_cb_qp_offset is not present, it is inferred to be equal to [[0]] The value of pps_cb_qp_offset + slice_cb_qp_offset should be in the range of -12 to +12 (inclusive).

[0896] It is stipulated that in determining Qp' Cr The value of the quantization parameter is the difference to be added to the value of pps_cr_qp_offset. The value of slice_cr_qp_offset shall be in the range -12 to +12 (inclusive). When slice_cr_qp_offset is not present, it is inferred to be equal to [[0]] The value of pps_cr_qp_offset + slice_cr_qp_offset should be in the range of -12 to +12 (including the end values).

[0897] It is stipulated that in determining Qp' CbCr The value of slice_joint_cbcr_qp_offset is the difference to be added to the value of pps_joint_cbcr_qp_offset_value. The value of slice_joint_cbcr_qp_offset shall be in the range of -12 to +12 (inclusive). When slice_joint_cbcr_qp_offset is not present, it is inferred to be equal to [[0]] The value of pps_joint_cbcr_qp_offset_value+slice_joint_cbcr_qp_offset should be in the range of -12 to +12 (including the end values).

[0898] 6.4. Fourth Group of Examples

[0899] This is a set of embodiments of items 4, 4.a, 4.b, 4.c and 4.d outlined in Section 5 above.

[0900] Specifies the maximum cbSubdiv value for intra slice codec units that transmit cu_qp_delta_abs and cu_qp_delta_sign_flag. The value of ph_cu_qp_delta_subdiv_intra_slice should be between 0 and 2*(CtbLog2SizeY-MinQtLog2SizeIntraY[[+ph_max_mtt_hierarchy_depth_intra_slice_luma]])+ (including the end value).

[0901] When not present, the value of ph_cu_qp_delta_subdiv_intra_slice is inferred to be equal to 0.

[0902] Specifies the maximum cbSubdiv value for codec units in intra slices that transmit cu_chroma_qp_offset_flag. The value of ph_cu_chroma_qp_offset_subdiv_intra_slice shall be between 0 and 2*(CtbLog2SizeY - MinQtLog2SizeIntraY[[+ph_max_mtt_hierarchy_depth_intra_slice_luma]])+ (including the end value).

[0903] When not present, the value of ph_cu_chroma_qp_offset_subdiv_intra_slice is inferred to be equal to 0.

[0904] Specifies the maximum cbSubdiv value for codec units in inter slices that transmit cu_qp_delta_abs and cu_qp_delta_sign_flag. The value of ph_cu_qp_delta_subdiv_inter_slice shall be between 0 and 2*(CtbLog2SizeY - MinQtLog2SizeInterY[[+ph_max_mtt_hierarchy_depth_inter_slice]])+ (including the end value).

[0905] When not present, the value of ph_cu_qp_delta_subdiv_inter_slice is inferred to be equal to 0.

[0906] Specifies the maximum cbSubdiv value for codec units in inter slices that transmit cu_chroma_qp_offset_flag. The value of ph_cu_chroma_qp_offset_subdiv_inter_slice shall be between 0 and 2*(CtbLog2SizeY - MinQtLog2SizeInterY[[+ph_max_mtt_hierarchy_depth_inter_slice]])+ (including the end value).

[0907] When not present, the value of ph_cu_chroma_qp_offset_subdiv_inter_slice is inferred to be equal to 0.

[0908] Figure 1 1 is a block diagram of an example video processing system 1900 that may implement 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 may be received 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 networks (PONs), etc.) and wireless interfaces (such as Wi-Fi or cellular interfaces).

[0909] System 1900 may include a codec component 1904 that can implement various codecs 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 generate a codec representation of the video. Therefore, codec technology is sometimes referred to as video compression or video transcoding technology. The output of codec component 1904 can be stored or sent via the connected communication, as represented by component 1906. The bitstream (or codec representation) of the storage or communication of the video received at input 1902 can be used by component 1908 to generate pixel values ​​or displayable video sent to display interface 1910. The process of generating user-visible video from the bitstream is sometimes referred to as video decompression. In addition, although some video processing operations are referred to as "codec" operations or tools, it should be understood that codec tools or operations are used at the encoder, and corresponding decoding tools or operations of the results of the inverse codec will be performed by the decoder.

[0910] Examples of peripheral bus interfaces or display interfaces may include Universal Serial Bus (USB) or High Definition Multimedia Interface (HDMI) or Displayport, etc. Examples of storage interfaces include SATA (Serial Advanced Technology Attachment), PCI, IDE interfaces, etc. The techniques described in this document may be implemented in various electronic devices, such as mobile phones, laptop computers, smart phones, or other devices capable of digital data processing and / or video display.

[0911] Figure 2 3600. The apparatus 3600 may be used to implement one or more of the methods described herein. The apparatus 3600 may be implemented in a smartphone, a tablet, a computer, an Internet of Things (IoT) receiver, etc. The apparatus 3600 may include one or more processors 3602, one or more memories 3604, and video processing circuitry 3606. The processor(s) 3602 may be configured to implement one or more of the methods described in this document. The memory(s) 3604 may be used to store data and code that is used to implement the methods and techniques described herein. The video processing circuitry 3606 may be used to implement some of the techniques described in this document in hardware circuitry.

[0912] Figure 4 is a block diagram illustrating an example video coding system 100 that may utilize the techniques of this disclosure.

[0913] like Figure 4As shown, the video codec 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 may decode the encoded video data generated by the source device 110, which may be referred to as a video decoding device.

[0914] Source device 110 may include a video source 112 , a video encoder 114 , and an input / output (I / O) interface 116 .

[0915] The video source 112 may include a source such as a video capture device, an interface for receiving video data from a video content provider, and / or a computer graphics system that generates video data, or a combination of these sources. The video data may include one or more pictures. The video encoder 114 encodes the video data from the video source 112 to generate a bit stream. The bit stream may include a sequence of bits that form a codec representation of the video data. The bit stream may include a codec picture and associated data. The codec picture is a codec representation of the picture. The associated data may include a sequence parameter set, a picture parameter set, and other syntax elements. The I / O interface 116 includes a modulator / demodulator (modem) and / or a transmitter. The encoded video data may be directly sent to the destination device 120 via the I / O interface 116 through the network 130a. The encoded video data may also be stored on a storage medium / server 130b for access by the destination device 120.

[0916] Destination device 120 may include an I / O interface 126 , a video decoder 124 , and a display device 122 .

[0917] The I / O interface 126 may include a receiver and / or a modem. The I / O interface 126 may obtain the encoded video data from the source device 110 or the storage medium / server 130b. The video decoder 124 may decode the encoded video data. The display device 122 may display the decoded video data to a user. The display device 122 may be integrated with the destination device 120, or may be external to the destination device 120 configured to interface with an external display device.

[0918] The video encoder 114 and the video decoder 124 may operate according to a video compression standard, such as the High Efficiency Video Codec (HEVC) standard, the Versatile Video Codec (VVC) standard, and other current and / or other standards.

[0919] Figure 5 is a block diagram showing an example of a video encoder 200, which may be Figure 4 The video encoder 114 in the system 100 is shown in FIG.

[0920] Video encoder 200 may be configured to perform any or all of the techniques of this disclosure. Figure 5 In the example of , video encoder 200 includes multiple functional components. The techniques described in this disclosure can be shared between various components of video encoder 200. In some examples, a processor can be configured to perform any or all of the techniques described in this disclosure.

[0921] 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.

[0922] 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 an IBC mode, where at least one reference picture is a picture where the current video block is located.

[0923] Furthermore, some components such as the motion estimation unit 204 and the motion compensation unit 205 may be highly integrated, but are not shown for the purpose of explanation. Figure 5 In the example, they are shown separately.

[0924] The partitioning unit 201 may partition a picture into one or more video blocks. The video encoder 200 and the video decoder 300 may support various video block sizes.

[0925] The mode selection unit 203 may select one of the intra or inter coding modes, for example, based on the error result, and provide the resulting intra or inter coding block to the residual generation unit 207 to generate residual block data and to the reconstruction unit 212 to reconstruct the coding block for use as a reference picture. In some examples, the mode selection unit 203 may select a combination of intra and inter prediction (CIIP) mode, where the prediction is based on an inter prediction signal and an intra prediction signal. The mode selection unit 203 may also select a resolution of motion vectors (e.g., sub-pixel or whole pixel accuracy) for blocks in the case of inter prediction.

[0926] To perform inter-frame prediction on the current video block, the motion estimation unit 204 may generate motion information of the current video block by comparing the current video block with one or more reference frames from the buffer 213. The motion compensation unit 205 may determine a predicted video block for the current video block based on the motion information and decoded samples of a picture from the buffer 213 (rather than a picture associated with the current video block).

[0927] Motion estimation unit 204 and motion compensation unit 205 may perform different operations for the current video block, for example, performing different operations depending on whether the current video block is in an I slice, a P slice, or a B slice.

[0928] In some examples, the motion estimation unit 204 may perform unidirectional prediction of the current video block, and the motion estimation unit 204 may search for a reference video block of the current video block in the reference picture of list 0 or list 1. The motion estimation unit 204 may then generate a reference index indicating a reference video block in the reference picture of list 0 or list 1 and a motion vector indicating a spatial displacement between the current video block and the reference video block. The motion estimation unit 204 may output the reference index, the prediction direction indicator, and the motion vector as motion information of the current video block. The motion compensation unit 205 may generate a predicted video block of the current block based on the reference video block indicated by the motion information of the current video block.

[0929] In other examples, the motion estimation unit 204 may perform bidirectional prediction of the current video block, and the motion estimation unit 204 may search for a reference video block of the current video block in the reference picture of list 0 and may also search for another reference video block of the current video block in the reference picture of list 1. The motion estimation unit 204 may then generate a reference index indicating a reference video block in the reference picture of list 0 or list 1 and a motion vector indicating a spatial displacement between the reference video block and the current video block. The motion estimation unit 204 may output the reference index and the motion vector of the current video block as motion information of the current video block. The motion compensation unit 205 may generate a predicted video block of the current video block based on the reference video block indicated by the motion information of the current video block.

[0930] In some examples, motion estimation unit 204 may output the entire set of motion information for use in a decoding process by a decoder.

[0931] In some examples, motion estimation unit 204 may not output a full set of motion information for the current video. Instead, motion estimation unit 204 may signal the motion information of the current video block with reference to 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 a neighboring video block.

[0932] In one example, motion estimation unit 204 may indicate in a syntax structure associated with the current video block a value that indicates to video decoder 300 that the current video block has the same motion information as another video block.

[0933] In another example, the motion estimation unit 204 may identify another video block and a motion vector difference (MVD) in a syntax structure associated with the current video block. The motion vector difference indicates the difference between the motion vector of the current video block and the motion vector of the indicated video block. The video decoder 300 may use the motion vector of the indicated video block and the motion vector difference to determine the motion vector of the current video block.

[0934] As discussed above, the video encoder 200 may predictively signal motion vectors. Two examples of predictive signaling techniques that may be implemented by the video encoder 200 include advanced motion vector prediction (AMVP) and merge mode signaling.

[0935] The intra prediction unit 206 may perform intra prediction on the current video block. When the intra prediction unit 206 performs intra prediction on the current video block, the intra prediction unit 206 may generate prediction data for the current video block based on decoded samples of other video blocks in the same picture. The prediction data for the current video block may include a predicted video block and various syntax elements.

[0936] The residual generation unit 207 can generate residual data for the current video block by subtracting (e.g., indicated by a minus sign) the predicted video block(s) of the current video block from the current video block. The residual data for the current video block may include residual video blocks corresponding to different sample components of samples in the current video block.

[0937] In other examples, such as in skip mode, there may be no residual data for the current video block, and the residual generation unit 207 may not perform a subtraction operation.

[0938] Transform processing unit 208 may generate one or more transform coefficient video blocks for the current video block by applying one or more transforms to the residual video block associated with the current video block.

[0939] After transform processing unit 208 generates a transform coefficient video block associated with the current video block, quantization unit 209 may 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.

[0940] The inverse quantization unit 210 and the inverse transform unit 211 may apply inverse quantization and inverse transform, respectively, to the transform coefficient video block to reconstruct the residual video block from the transform coefficient video block. The reconstruction unit 212 may add the reconstructed residual video block to the corresponding samples from one or more prediction video blocks generated by the prediction unit 202 to generate a reconstructed video block associated with the current block for storage in the buffer 213.

[0941] After the reconstruction unit 212 reconstructs the video block, a loop filtering operation may be performed to reduce video blocking artifacts in the video block.

[0942] The entropy coding unit 214 may receive data from other functional components of the video encoder 200. When the entropy coding unit 214 receives data, the entropy coding unit 214 may perform one or more entropy coding operations to generate entropy-coded data and output a bitstream including the entropy-coded data.

[0943] Some embodiments of the disclosed technology include making a decision or determining to enable a video processing tool or mode. In one example, when a video processing tool or mode is enabled, the encoder will use or implement the tool or mode in the processing of a block of a video, but will not necessarily modify the resulting bitstream based on the use of the tool or mode. That is, when a video processing tool or mode is enabled based on the decision or determination, the conversion from a block of a video to a bitstream (or bitstream representation) of the video will use the video processing tool or mode. In another example, when a video processing tool or mode is enabled, the decoder will process the bitstream knowing that the bitstream has been modified based on the video processing tool or mode. That is, the conversion from the bitstream of the video to the block of the video will be performed using the video processing tool or mode enabled based on the decision or determination.

[0944] Figure 6 is a block diagram showing an example of a video decoder 300, which may be Figure 4 The video decoder 114 in the system 100 is shown in FIG.

[0945] Video decoder 300 may be configured to perform any or all of the techniques of this disclosure. Figure 6 In the example of , video decoder 300 includes multiple functional components. The techniques described in this disclosure can be shared between various components of video decoder 300. In some examples, a processor can be configured to perform any or all of the techniques described in this disclosure.

[0946] exist Figure 6In the example of , 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 be performed with respect to the video encoder 200 ( Figure 5 ) is a decoding process that is the overall inverse of the encoding process described.

[0947] The entropy decoding unit 301 may retrieve a coded bitstream. The coded bitstream may include entropy coded video data (e.g., coded blocks of video data). The entropy decoding unit 301 may decode the entropy coded video, and based on the entropy decoded video data, the motion compensation unit 302 may determine motion information including motion vectors, motion vector precision, reference picture list index, and other motion information. The motion compensation unit 302 may determine such information, for example, by performing AMVP and merge modes.

[0948] The motion compensation unit 302 may generate a motion compensated block, possibly interpolated based on an interpolation filter. An identifier of the interpolation filter to be used with sub-pixel precision may be included in the syntax element.

[0949] The motion compensation unit 302 may calculate interpolated values ​​of a sub-integer number of pixels of the reference block using an interpolation filter used by the video encoder 200 during encoding of the video block. The motion compensation unit 302 may determine the interpolation filter used by the video encoder 200 based on received syntax information and use the interpolation filter to generate a prediction block.

[0950] 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) slices of the coded video sequence, the partitioning information describing how each macroblock of the pictures of the coded video sequence is partitioned, the mode indicating how to encode each partition, one or more reference frames (and reference frame lists) for each inter-frame coded block, and other information for decoding the coded video sequence.

[0951] The intra prediction unit 303 may form a prediction block from spatially neighboring blocks using, for example, an intra prediction mode received in the bitstream. The inverse quantization unit 303 inversely quantizes (i.e., dequantizes) the quantized video block coefficients provided in the bitstream and decoded by the entropy decoding unit 301. The inverse transform unit 303 applies an inverse transform.

[0952] The reconstruction unit 306 may sum the residual block with the corresponding prediction block generated by the motion compensation unit 202 or the intra prediction unit 303 to form a decoded block. As desired, a deblocking filter may 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 reference blocks for subsequent motion compensation / intra prediction and also produces decoded video for presentation on a display device.

[0953] The following sections describe an example PROF technique, an example affine merge technique, and an example affine AMVP technique:

[0954] PROF: Prediction Refinement using Optical Flow (PROF) is used to refine the sub-block based affine motion compensated prediction. After performing sub-block based affine motion compensation, the luma prediction samples are refined by adding the difference values ​​derived from the optical flow equation. Thus, for example, the PROF technique includes refining the sub-block based affine motion compensated prediction of a video block, followed by refining the luma prediction samples of the video block by adding the difference values ​​derived from the optical flow equation.

[0955] Affine merge: In this mode, the CPMV (control point motion vector) of the current CU is generated based on the motion information of the spatially neighboring CUs. Several CPMVP (control point motion vector prediction value) candidates are constructed from the motion information of the spatially neighboring CUs. An index is signaled to indicate the index used for the current CU. Thus, for example, in affine merge mode, the control point motion vector of the current codec unit of the video block is generated based on the motion information of the spatially neighboring codec units of the current codec unit, and an index indicating the affine merge candidate from the sub-block merge candidate list to be used for the current codec unit is included in the bitstream.

[0956] Affine AMVP: An affine flag at the CU level is signaled in the bitstream to indicate whether the affine AMVP mode is used, and then another flag is signaled to indicate whether 4-parameter affine or 6-parameter affine. In this mode, the difference between the CPMV of the current CU and their predictor CPMVP is signaled in the bitstream. Thus, for example, the affine AMVP mode includes in the bitstream: (1) an affine flag at the codec unit level of the video block to indicate whether the affine advanced motion vector prediction mode is used, (2) a second flag to indicate whether 4-parameter affine or 6-parameter affine is used, (3) a control point motion vector predictor index at the codec unit level, and (4) the difference between the control point motion vector of the current codec unit of the video block and the predictor control point motion vector corresponding to the control point motion vector.

[0957] Next, a list of preferred solutions for some embodiments is provided.

[0958] The following solution illustrates an example embodiment of the techniques discussed in the previous section (eg, items 1.1 to 1.c).

[0959] 1. A video processing method (eg, Figure 3 ), comprising: performing a conversion between videos including one or more video pictures (3002), wherein the one or more video pictures include one or more video slices, wherein the conversion complies with a first rule, wherein the first rule stipulates that a decision on the applicability of a deblocking filter for one or more video slices of a reference video picture parameter set is performed based on a deblocking syntax field included in a picture header of the corresponding video picture.

[0960] 2. The method of solution 1, wherein the decision is based on whether the applicability is disabled in the video picture parameter set and the picture header, and also based on a slice level indication of the disabling of the deblocking filter.

[0961] 3. A method as in any of solutions 1-2, wherein the conversion further complies with a second rule that allows the applicability of signaling of a deblocking filter at a higher level in the codec representation to be overridden based on a flag signaled or derived at a level finer than a higher level in the codec representation.

[0962] 4. The method of solution 1, wherein whether the flag is signaled or whether the flag is derived depends on another field included in the codec representation.

[0963] The following solution illustrates an example embodiment of the techniques discussed in the previous section (eg, items 1.d to 1.q).

[0964] 5. A video processing method, comprising: performing a conversion between videos including one or more video pictures, the one or more video pictures including one or more video slices, wherein the conversion complies with a rule, the rule providing for constraining the applicability of a deblocking filter for a video slice based on fields included at a slice header level and / or a picture header level and / or a picture parameter set level of the video slice.

[0965] 6. The method of solution 5, wherein the rule specifies a constraint that, if the deblocking filter is disabled according to signaling at the picture parameter set level, the deblocking filter cannot be enabled by signaling at the slice header level or the picture header level.

[0966] 7. The method of solution 5, wherein the rule specifies a constraint that, in the case where the deblocking filter is enabled according to signaling at the picture parameter set level, signaling at the slice header level or the picture header level is allowed to disable the deblocking filter of the video slice.

[0967] 8. The method of solution 5, wherein the rule dictates that the value of a first field controlling the enabling of a deblocking filter at a picture parameter set level is independent of the value of a second field indicating whether the deblocking filter is overridden.

[0968] 9. The method of solution 5, wherein the rule specifies that the signaling of the syntax element "dbf_info_in_ph_flag" included in the picture parameter set is independent of the signaling of the syntax element "dbf_info_in_ph_flag" included in the picture parameter set.

[0969] Other syntax elements of enabled_flag, the syntax element "dbf_info_in_ph_flag" specifies whether the deblocking filter on / off control parameters and / or deblocking filter parameters are present in the picture header or sequence header.

[0970] 10. The method of solution 5, wherein the rule stipulates that the override flag at the picture parameter set level or the picture level or the slice level does not control the override of the deblocking on / off control parameter.

[0971] 11. The method of solution 5, wherein the rule stipulates that the override flag at the picture parameter set level or the picture level or the slice level is used to override the on / off control parameters or the filter parameters of the deblocking filter, but not both.

[0972] 12. The method of solution 5, wherein the rule stipulates that the deblocking filter is allowed to be enabled at the picture level or slice level even if the deblocking filter is disabled at the picture parameter set level.

[0973] 13. The method of solution 5, wherein a rule stipulates that a field controlling on / off of a deblocking filter and a field indicating a parameter of the deblocking filter are included at a picture level and a slice level.

[0974] 14. The method of solution 5, wherein a rule stipulates that a field for controlling on / off of a deblocking filter and a field for indicating parameters of the deblocking filter are included in a sequence parameter set.

[0975] 15. The method of solution 5, wherein the applicability of the deblocking filter for the video slice is signaled in a syntax field, the syntax field is signaled at a video unit level, wherein the syntax field is not a binary flag, and wherein the video unit level comprises a picture parameter set or a sequence parameter set.

[0976] 16. The method of solution 15, wherein the syntax field comprises N bits, wherein N is an integer greater than 1.

[0977] 17. The method of solution 16, wherein N=2, and wherein the syntax field indicates four options, including one or more of the following: (a) the deblocking filter is not applied to all slices of the reference picture parameter set (PPS), (b) the deblocking filter is applied to all slices of the reference PPS using a first offset parameter signaled in the PPS, (c) the deblocking filter is applied to all slices of the reference PPS using a second offset parameter signaled in the PPS, or (d) the deblocking filter is applied to the slices of the reference PPS by parameters other than those signaled in the PPS.

[0978] 18. The method of solution 5, wherein the rule provides for enabling a deblocking filter for a video slice using a zero value for a deblocking filter parameter.

[0979] The following solution illustrates an example embodiment of the technique discussed in the previous section (eg, item 2).

[0980] 19. A video processing method, comprising: determining the applicability of a prediction refinement based optical flow (PROF) codec and an affine advanced motion vector prediction codec based on a first rule or an affine merge mode based on a second rule; and performing conversion between a video block of a video and a codec representation of the video based on the determination.

[0981] 20. The method of solution 1, wherein the second rule provides for applying PROF codec to the video block such that the prediction block corresponding to the M*N portion is larger than M*N, where M and N are positive integers.

[0982] 21. The method of any one of solutions 19-20, comprising a flag in the codec representation to indicate the number of extended samples generated by the prediction block generated by the PROF codec.

[0983] 22. The method of solution 21, wherein the number of extended samples is the same for the first rule and the second rule.

[0984] The following solution illustrates an example embodiment of the technique discussed in the previous section (eg, item 3).

[0985] 23. A video processing method, comprising: performing conversion between a video comprising one or more pictures including one or more slices and a codec representation of the video, wherein a first syntax element at a picture level or a slice level and / or a second syntax element at another level indicating a quantization parameter increment or offset signaling notification is conditionally included in the codec representation according to a rule.

[0986] 24. The method of solution 23, wherein the rule specifies that the other level is a sequence parameter set level or a picture parameter set level, and wherein the second syntax element indicates whether chroma delta QP signaling or luma delta QP signaling is enabled.

[0987] 25. The method of solution 23, wherein the rule specifies that the other level is a sequence parameter set level or a picture parameter set level, and wherein the second syntax element indicates whether chroma QP offset signaling is enabled.

[0988] The following solution illustrates an example embodiment of the technique discussed in the previous section (eg, item 4).

[0989] 26. A video processing method, comprising: performing conversion between a video comprising one or more pictures including one or more slices and a codec representation of the video, wherein the codec representation comprises a syntax element indicating a codec block subdivision value (cbSubDiv), the range of the codec block subdivision value being according to a rule.

[0990] 27. The method of solution 26, wherein the rule specifies that the range is independent of the syntax field ph_max_mtt_hierarchy_depth_intra_slice_luma included in the codec representation.

[0991] 28. The method of any of Solutions 26-27, wherein the rule specifies a range between 0 and 2*(CtbLog2SizeY-MinQtLog2SizeIntraY)+2*(CtbLog2SizeY-MinCbLog2SizeY) (including the end values).

[0992] 29. The method of solution 26 wherein the rule specifies a range independent of the ph_max_mtt_hierarchy_depth_intra_slice_luma field.

[0993] 30. The method of solution 26 wherein the rule specifies that the range is independent of the ph_max_mtt_hierarchy_depth_inter_slice field.

[0994] 31. The method of any one of solutions 1 to 30, wherein the conversion comprises encoding the video into a codec representation.

[0995] 32. The method of any one of solutions 1 to 30, wherein converting comprises decoding a codec representation to generate pixel values ​​of the video.

[0996] 33. A video decoding device, comprising a processor configured to implement the method described in one or more of solutions 1 to 32.

[0997] 34. A video encoding device, comprising a processor configured to implement the method described in one or more of solutions 1 to 32.

[0998] 35. A computer program product having computer code stored thereon, which, when executed by a processor, causes the processor to implement the method of any one of solutions 1 to 32.

[0999] 36. The method, apparatus or system described in this document.

[1000] Figure 7 is a flow chart of an example method 700 of video processing. Operation 702 includes performing conversion between a video including a picture including one or more slices and a bitstream of the video, wherein the conversion complies with a rule that specifies whether to apply a deblocking filter to one or more slices of a reference picture parameter set based on at least a first syntax element included in the picture parameter set, and wherein the first syntax element indicates whether to disable the deblocking filter for the picture.

[1001] In some embodiments of the method 700, the rule specifies whether to apply a deblocking filter to one or more slices of the reference picture parameter set is also based on at least one of: (1) whether the deblocking filter is disabled for the picture by a second syntax element in the picture header, (2) whether the deblocking filter is indicated as disabled by a third syntax element at the slice level, or (3) whether a fourth syntax element in the picture parameter set indicates whether an override of deblocking filter applicability is disabled at the picture level and the slice level. In some embodiments of the method 700, the rule specifies whether to apply a deblocking filter to one or more slices of the reference picture parameter set is also based on: (1) whether the deblocking filter is disabled for the picture by a second syntax element in the picture header, and (2) whether the deblocking filter is indicated as disabled at the slice level by a third syntax element. In some embodiments of the method 700, the values ​​of the first syntax element, the second syntax element, and the third syntax element being equal to 1 indicates that the deblocking filter is disabled.

[1002] In some embodiments of the method 700, the rule specifies whether to apply a deblocking filter to one or more slices of the reference picture parameter set is further based on whether a fourth syntax element in the picture parameter set indicates an override of whether to disable applicability of the deblocking filter at a picture level and a slice level. In some embodiments of the method 700, a first value of the first syntax element equal to 1 indicates that the deblocking filter is disabled for a picture of the reference picture parameter set, and a second value of the fourth syntax element equal to 0 indicates that the override of applicability of the deblocking filter is disabled at a picture level and a slice level. In some embodiments of the method 700, a value of the first syntax element equal to 1 and a value of the fourth syntax element equal to 0 indicates that the deblocking filter is disabled.

[1003] Figure 8 8 is a flow chart of an example method 800 of video processing. Operation 802 includes performing conversion between a video including a picture including one or more slices and a bitstream of the video, wherein the conversion complies with a rule that specifies whether a deblocking filter is applied to one or more slices of a reference picture parameter set based only on a syntax element included in the picture parameter set that indicates whether the deblocking filter is disabled.

[1004] In some embodiments of method 800 , a value of this syntax element equal to 1 indicates that a deblocking filter is disabled for the picture.

[1005] Fig. 9 is a flow chart of an example method 900 of video processing. Operation 902 includes performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video, wherein the bitstream complies with a rule, wherein the rule provides for determining whether deblocking of a slice or a picture is to be overridden at a slice level or at a picture level based on a first value of a first syntax element at a slice level or a second value of a second syntax element at a picture level, and wherein the rule provides for determining a first value of the first syntax element independently of a second value of a second syntax element at a picture level in response to the first syntax element not being present in a slice header.

[1006] In some embodiments of method 900, the first value of the first syntax element is determined to be 0, indicating that deblocking is not covered at the slice level. In some embodiments of method 800, the second value of the second syntax element is determined to be 0, indicating that deblocking is not covered at the picture level.

[1007] Fig.10is a flow chart of an example method 1000 of video processing. Operation 1002 includes performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video, wherein the bitstream complies with a rule, wherein the rule provides for determining whether a deblocking parameter is included in a slice header or a picture header based on a first value of a first syntax element at a slice level or a second value of a second syntax element at a picture level, and wherein the rule provides for determining a first value of the first syntax element independently of a second value of a second syntax element at a picture level in response to the first syntax element not being present in the slice header.

[1008] In some embodiments of method 1000, the first value of the first syntax element is determined to be 0, indicating that the deblocking parameters are not included at the slice level. In some embodiments of method 1000, the second value of the second syntax element is determined to be 0, indicating that the deblocking parameters are not included at the picture level.

[1009] Fig.11 is a flow chart of an example method 1100 of video processing. Operation 1102 includes performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video, wherein the bitstream conforms to a format rule, the format rule specifying whether a first syntax element and a second syntax element are included in a picture header and a slice header, respectively, or are inferred based on a value of a third syntax element in a picture parameter set, wherein the first syntax element indicates whether a deblocking filter is disabled at a picture level of the video, wherein the second syntax element indicates whether a deblocking filter is disabled at a slice level of the video, and wherein the third syntax element indicates whether a deblocking filter is enabled for one or more pictures of a reference picture parameter set.

[1010] Fig.12 12 is a flow chart of an example method 1200 for video processing. Operation 1202 includes performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video, wherein the conversion complies with a rule that specifies whether a deblocking filter is applied to a slice is based on a syntax element included in a slice header and / or a picture header and / or a picture parameter set referenced by the slice, and wherein the syntax element indicates whether the deblocking filter is enabled at a picture parameter set level and / or a slice level and / or a picture level.

[1011] In some embodiments of the method 1200, the rule provides that, in the case where the deblocking filter is disabled according to the first syntax element in the picture parameter set, then enabling the deblocking filter by the second syntax element in the slice header or the third syntax element in the picture header is not allowed. In some embodiments of the method 1200, the rule further provides that the presence of the second syntax element in the slice header and / or the third syntax element in the picture header is based on the first value of the first syntax element and is independent of the second value of the flag, the flag indicating whether an override of the applicability of the deblocking filter is enabled at the picture level or at the slice level. In some embodiments of the method 1200, the rule provides that in response to the first syntax element indicating that the deblocking filter is disabled for a slice of the reference picture parameter set, the second syntax element and / or the third syntax element are excluded from the slice header and / or the picture header, respectively. In some embodiments of the method 1200, the rule further provides that a flag in the picture parameter set indicates: (1) whether the first syntax element is indicated in the picture parameter set, whether the second syntax element is indicated in the slice header, and / or whether the third syntax element is indicated in the picture, and (2) whether parameters of the deblocking filter are indicated in the picture parameter set, the picture header, and the slice header. In some embodiments of the method 1200, the flag indicates: (1) the first syntax element is excluded from the picture parameter set, the second syntax element is excluded from the slice header, and / or the third syntax element is excluded from the picture, and (2) parameters for the deblocking filter are excluded from the picture parameter set, the picture header, and the slice header.

[1012] In some embodiments of the method 1200, the rule provides that, in the case where the deblocking filter is disabled according to a first syntax element not present in a picture parameter set, then enabling the deblocking filter by a second syntax element in a slice header or a third syntax element in a picture header is not allowed, and the first syntax element is inferred to be equal to a specific value. In some embodiments of the method 1200, the rule provides that, in the case where the deblocking filter is disabled according to a first syntax element in a picture parameter set, then enabling the deblocking filter by a second syntax element in a slice header or a third syntax element not present in a picture header is not allowed, and the third syntax element is inferred to have the same value as the first syntax element. In some embodiments of the method 1200, the rule provides that, in the case where the deblocking filter is disabled according to a first syntax element in a picture parameter set, enabling the deblocking filter by a second syntax element not present in a slice header or a third syntax element in a picture header is not allowed, and the second syntax element is inferred to have the same value as the first syntax element or the third syntax element. In some embodiments of the method 1200, the rule provides that, in the case where the deblocking filter is enabled at a first video unit level of a video, then disabling the deblocking filter at a second video unit level of the video is allowed, wherein the second video unit level is lower than the first video unit level.

[1013] In some embodiments of the method 1200, the first video unit level includes a picture header, and wherein the second video unit level includes a slice header. In some embodiments of the method 1200, one or more pictures include a plurality of slices, the plurality of slices including a first group of one or more slices and a second group of one or more slices, the rule provides for enabling a deblocking filter for the first group of one or more slices, and the rule provides for disabling the deblocking filter for the second group of one or more slices. In some embodiments of the method 1200, a first syntax element included in the slice header indicates whether the deblocking filter is enabled for the second video unit level, a second syntax element in the picture header indicates whether the deblocking filter is enabled for the first video unit level, and the rule provides for the first syntax element to be based on the second syntax element. In some embodiments of the method 1200, the rule provides for, in the case where the first syntax element indicates that the deblocking filter is enabled for the current picture, the second syntax element indicates whether the deblocking filter is enabled for the current slice of the current picture. In some embodiments of the method 1200, the rule further provides for whether the picture parameter set includes a first flag indicating whether a syntax element and / or parameter for a deblocking filter is included in a slice header or a picture header independent of one or more other syntax elements. In some embodiments of the method 1200 , the one or more other syntax elements include a second flag indicating whether an override of the applicability of the deblocking filter at the picture level and the slice level is enabled.

[1014] In some embodiments of the method 1200, the rule specifies that whether the second syntax element is included in the slice header or the third syntax element is included in the picture header is based on a first flag in the picture parameter set and / or a first syntax element and is independent of the second flag, the first syntax element indicating whether a deblocking filter is enabled for a slice of a reference picture parameter set, the second syntax element indicating whether the deblocking filter is enabled for a slice level, and the third syntax element indicating whether the deblocking filter is enabled for a picture level. In some embodiments of the method 1200, the first flag in the picture parameter set or the second flag in the slice header or the third flag in the picture header indicates whether an override of deblocking filter applicability is enabled at a picture parameter set level or a picture level or a slice level, respectively, and the rule further specifies that the first flag or the second flag or the third flag is configured only to override parameters of the deblocking filter, except for: (1) a first syntax element in the picture parameter set indicating whether the deblocking filter is enabled at the picture parameter set level, or (2) a second syntax element in the slice header indicating whether the deblocking filter is enabled at the slice level, or (3) a third syntax element in the picture header indicating whether the deblocking filter is enabled at the picture level. In some embodiments of method 1200, according to the rule, the first syntax element is selectively included in the picture parameter set before the first flag, or according to the rule, the second syntax element is selectively included in the slice header before the second flag, or according to the rule, the third syntax element is selectively included in the picture header before the third flag, and the rule specifies whether the first flag, the second flag, or the third flag is included in the picture parameter set, the slice header, or the picture header, respectively, based on the first syntax element, the second syntax element, or the third syntax element, respectively.

[1015] In some embodiments of the method 1200, the syntax element includes a first syntax element, and the rule further provides that the picture parameter set includes the first syntax element, the first syntax element indicating whether a deblocking filter is enabled for one or more slices of the reference picture parameter set. In some embodiments of the method 1200, the rule further provides that whether the picture parameter set includes the first syntax element is independent of one or more other syntax elements in the picture parameter set, the first syntax element indicating whether a deblocking filter is enabled for one or more slices of the reference picture parameter set. In some embodiments of the method 1200, the rule further provides that, in the event that the deblocking filter is disabled at a first video unit level of the video, one or more syntax elements at a second video unit level of the video are not present and are inferred to be equal to a value of the first syntax element of the first video unit level indicating that the deblocking filter is disabled, and the first video unit level is higher than the second video unit level. In some embodiments of method 1200, the rule further provides that a syntax element in a picture parameter set indicating the presence of global control of a deblocking filter is configured only to control the presence of: (1) one or more flags in a picture parameter set or a picture header or a slice header, the one or more flags indicating whether an override of the applicability of the deblocking filter is enabled at a picture parameter set level or a picture level or a slice level, and (2) parameters of the deblocking filter of a picture parameter set, a picture header or a slice header.

[1016] In some embodiments of method 1200, the rule further provides that a flag indicates whether an override is enabled for the applicability of the deblocking filter or the first set of parameters for the deblocking filter. In some embodiments of method 1200, the flag is included in a picture parameter set or a picture header or a slice header. In some embodiments of method 1200, the rule further provides that, in the case where the flag indicates whether an override is enabled for the applicability of the deblocking filter, then: (1) the first set of parameters for the deblocking filter is included only at a first video unit level of the video, and (2) in response to enabling the deblocking filter at a second video unit level, a second set of parameters for the deblocking filter at the second video unit level of the video is inferred from the first set of parameters for the deblocking filter at the first video unit level, and wherein the first video unit level is higher than the second video unit level. In some embodiments of method 1200, the rule further provides that, in a case where a flag indicates whether an override is enabled for a first set of parameters for a deblocking filter included in a first video unit level of a video, then: (1) applicability of the deblocking filter is included only at the first video unit level, and (2) in response to enabling the deblocking filter at the second video unit level, a second set of parameters for the deblocking filter at the second video unit level of the video is inferred from the first set of parameters for the deblocking filter at the first video unit level, and wherein the first video unit level is higher than the second video unit level.

[1017] In some embodiments of the method 1200, the first video unit level includes a picture parameter set, and wherein the second video unit level includes a picture header or a slice header. In some embodiments of the method 1200, the syntax element includes a first syntax element for a first video unit level of the video and a second syntax element for a second video unit level of the video, wherein the first syntax element and the second syntax element indicate whether a deblocking filter is enabled at the first video unit level and the second video unit level, respectively, wherein the first video unit level is higher than the second video unit level, wherein the rule further provides that in response to the first syntax element indicating that the deblocking filter is disabled at the first video unit level, an override of the second syntax element is not allowed. In some embodiments of the method 1200, the first video unit level includes a picture parameter set, and wherein the second video unit level includes a picture header or a slice header. In some embodiments of the method 1200, the rule provides that whether the second syntax is included in the second video unit level is based on whether the first syntax element indicates that the deblocking filter is allowed to be controlled in the first video unit level.

[1018] In some embodiments of the method 1200, the syntax elements include a first syntax element at a first video unit level of the video and a second syntax element at a second video unit level of the video, the first syntax element and the second syntax element respectively indicating whether a deblocking filter is enabled at the first video unit level and the second video unit level, and the rule specifies that in response to the absence of the second syntax element at the second video unit level, the deblocking filter is inferred to have a specific state for the second video unit level. In some embodiments of the method 1200, the specific state includes disabled, enabled, or the same state as the deblocking filter indicated by the first syntax element. In some embodiments of the method 1200, the rule specifies that the picture parameter set does not include a syntax element indicating whether a global control of the deblocking filter exists, the rule specifies that the picture parameter set includes a first syntax element indicating whether the deblocking filter is enabled, and the first syntax element is independent of the syntax element. In some embodiments of the method 1200, the second syntax element indicates whether to allow the applicability of the deblocking filter to be overridden, wherein the rule specifies that whether the picture parameter set includes the second syntax element is based on the first syntax element indicating that the deblocking filter is enabled. In some embodiments of the method 1200 , the rule specifies that whether the parameters of the deblocking filter are included in the picture parameter set is based on a second syntax element indicating an override that allows applicability of the deblocking filter.

[1019] In some embodiments of the method 1200, the rule provides that the picture parameter set does not include a syntax element indicating whether there is global control of the deblocking filter, the rule provides that the picture parameter set includes a first syntax element indicating whether an override of the applicability of the deblocking filter is allowed, and the first syntax element is independent of the syntax element. In some embodiments of the method 1200, the second syntax element indicates whether the deblocking filter is enabled, and the rule provides that whether the picture parameter set includes the second syntax element is based on the first syntax element indicating that an override of the applicability of the deblocking filter is allowed. In some embodiments of the method 1200, the rule provides that whether the parameters of the deblocking filter are included in the picture parameter set is based on the second syntax element indicating that the deblocking filter is enabled. In some embodiments of the method 1200, the rule provides that the picture header includes a syntax element indicating whether the picture header or the slice header includes one or more syntax elements indicating whether the deblocking filter is enabled and / or parameters of the deblocking filter.

[1020] In some embodiments of the method 1200, the rule provides for excluding syntax elements from the picture parameter set. In some embodiments of the method 1200, the rule provides for each of the picture header and the slice header to include one or more syntax elements indicating whether a deblocking filter is enabled and / or parameters of the deblocking filter.

[1021] Fig.13 13 is a flow chart of an example method 1300 for video processing. Operation 1302 includes performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video, wherein the conversion complies with a rule that specifies whether a deblocking filter is applied to a slice is based on a syntax element included in a sequence parameter set referenced by the slice, and wherein the syntax element includes a first syntax element indicating whether a deblocking filter is enabled and / or a set of syntax elements indicating a first set of parameters for the deblocking filter.

[1022] In some embodiments of method 1300, the rule further provides that a first syntax element in a sequence parameter set at a first video unit level of the video is overridden by a second syntax element indicating whether a deblocking filter is enabled at a second video unit level of the video, and the first video unit level is higher than the second video unit level.

[1023] In some embodiments of the method 1300, the rule further provides that a first set of parameters for a deblocking filter indicated in a sequence parameter set at a first video unit level of the video is overwritten by a second set of parameters for a deblocking filter indicated at a second video unit level of the video, and the first video unit level is higher than the second video unit level. In some embodiments of the method 1300, the second video unit level includes a picture parameter set, a picture header, or a slice header.

[1024] Fig.14 14 is a flow chart of an example method 1400 for video processing. Operation 1402 includes performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video, wherein the conversion complies with a rule that specifies whether a deblocking filter is applied to a slice is based on a non-binary syntax element included in a video unit level, and wherein the non-binary syntax element indicates whether and / or how a deblocking filter is applied to the one or more slices.

[1025] In some embodiments of the method 1400, the video unit level includes a picture parameter set or a sequence parameter set. In some embodiments of the method 1400, a rule specifies that a non-binary syntax element indicates a deblocking mode, and wherein the non-binary syntax element includes N bits. In some embodiments of the method 1400, N=2. In some embodiments of the method 1400, the rule specifies that a first value of the non-binary syntax element indicates that a deblocking filter is not applied to all slices of a reference picture parameter set, the rule specifies that a second value of the non-binary syntax element indicates that a deblocking filter is applied to all slices of a reference picture parameter set using a 0-valued deblocking parameter offset of β and tC, the rule specifies that a third value of the non-binary syntax element indicates that a deblocking filter is applied to all slices of a reference picture parameter set using a deblocking parameter offset of β and tC explicitly included in the picture parameter set, and the rule specifies that a fourth value of the non-binary syntax element indicates whether a deblocking filter is applied to a slice of a reference picture parameter set is controlled by a parameter present in a picture header or a slice header of the slice. In some embodiments of the method 1400 , the rule specifies whether the parameters of the deblocking filter are included in the picture parameter set based on the value of the non-binary syntax element.

[1026] In some embodiments of the method 1400, the rule provides that in response to a value satisfying a specific condition, the parameters of the deblocking filter are included in the picture parameter set, and in response to a value not satisfying the specific condition, the parameters of the deblocking filter are inferred to be 0. In some embodiments of the method 1400, the specific condition includes whether the value is greater than an integer. In some embodiments of the method 1400, the rule provides that the value of a non-binary syntax element controls whether a syntax element is included in the picture parameter set, and the syntax element specifies whether a picture header or a slice header includes a syntax element indicating whether a deblocking filter is enabled and / or a parameter of the deblocking filter. In some embodiments of the method 1400, the rule provides that in response to a value of a non-binary syntax element satisfying a specific condition, the syntax element is included in the picture parameter set. In some embodiments of the method 1400, the specific condition includes whether the value is equal to an integer. In some embodiments of the method 1400, the rule provides that in response to the syntax element being excluded from the picture parameter set, the syntax element is inferred to have a specific value. In some embodiments of the method 1400 , the rule provides that the value of the non-binary syntax element controls whether the syntax element is included in a picture header or a slice header, and the syntax element indicates whether a deblocking filter is enabled and / or parameters of the deblocking filter.

[1027] In some embodiments of the method 1400, the rule provides that, in response to a value of a non-binary syntax element satisfying a particular condition, a syntax element indicating whether a deblocking filter is enabled at a picture level of the video is indicated in a picture header. In some embodiments of the method 1400, the rule provides that, in response to a value of a non-binary syntax element satisfying a particular condition, a syntax element indicating whether a deblocking filter is enabled at a slice level of the video is indicated in a slice header. In some embodiments of the method 1400, the particular condition includes whether the value is equal to an integer.

[1028] Fig.15 15 is a flow chart of an example method 1500 for video processing. Operation 1502 includes performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video, wherein the conversion complies with a rule specifying that: (1) a deblocking filter is enabled at a picture level of the video or a slice level of the video, and (2) zero-valued deblocking parameter offsets of β and tC are used for parameters of the deblocking filter.

[1029] In some embodiments of the method 1500, the rule provides that the picture parameter set includes one or more syntax elements indicating whether the default parameters of the deblocking filter are associated with zero-valued deblocking parameter offsets of β and tC or with user-defined β and tC offsets. In some embodiments of the method 1500, in response to one or more syntax elements indicating that the default parameters of the deblocking filter are associated with user-defined β and tC offsets, the picture parameter set includes the user-defined β and tC offsets. In some embodiments of the method 1500, the parameters of the deblocking filter and the default parameters of the deblocking filter are selectively overridden at a picture level of the video or at a slice level of the video. In some embodiments of the method 1500, the rule provides that the video unit level of the video includes one or more syntax elements indicating whether to use zero-valued deblocking parameter offsets of β and tC or whether to use user-defined β and tC offsets. In some embodiments of the method 1500, in response to one or more syntax elements indicating the use of user-defined β and tC offsets, the video unit level includes the user-defined β and tC offsets. In some embodiments of the method 1500 , the video unit level includes a sequence parameter set, a picture parameter set, a picture header, or a slice header.

[1030] Fig.16 16 is a flow chart of an example method 1600 for video processing. Operation 1602 includes determining a size of a prediction block corresponding to a video block for conversion between a video block of a video and a bitstream of the video according to a rule. Operation 1604 includes performing the conversion based on the determination, wherein the rule specifies determining a first size of the prediction block in response to whether a prediction refinement technique using optical flow is used to encode and decode the video block, and wherein the video block has a second size and is encoded and decoded using an affine merge mode or an affine advanced motion vector prediction mode.

[1031] In some embodiments of the method 1600, a first width and a first height of a first size of the prediction block are indicated by (M+M0) and (N+N0), respectively, a second width and a second height of a second size of the video block are indicated by M and N, respectively, and M0 is greater than or equal to 0, and N0 is greater than or equal to 0. In some embodiments of the method 1600, M0 and N0 are not both equal to 0. In some embodiments of the method 1600, M0 and N0 are equal to 2. In some embodiments of the method 1600, a flag indicating whether a prediction refinement technique using optical flow is utilized controls whether and / or how many extended samples are included in the prediction block of the first size. In some embodiments of the method 1600, the first size of the prediction block is based on the number of extended samples, and the number of extended samples is independent of whether the first video block is encoded and decoded using an affine merge mode or according to an affine advanced motion vector prediction mode. In some embodiments of method 1600, a first width and a first height of a first size of the prediction block are indicated by (M+X) and (N+Y), respectively, a second width and a second height of a second size of the video block are indicated by M and N, respectively, and X is the number of extended samples of the width. Y is the number of extended samples of the height. In some embodiments of method 1600, X and Y are equal to 0. In some embodiments of method 1600, X and Y are equal to 2.

[1032] In some embodiments of method 1600, in response to the value of the flag indicating that the prediction refinement technique using optical flow is utilized, X and Y are equal to 2. In some embodiments of method 1600, the value of the flag is equal to 1. In some embodiments of method 1600, the first size of the prediction block is based on a boundary extension size that is based on the value of the flag indicating whether the prediction refinement technique using optical flow is utilized, and the boundary extension size indicates the number of extension samples by which the second size of the video block is increased to obtain the first size of the prediction block. In some embodiments of method 1600, the number of extension samples is 0. In some embodiments of method 1600, the number of extension samples is 2. In some embodiments of method 1600, the prediction refinement technique using optical flow includes refining a sub-block based affine motion compensated prediction of the video block, and then refining the luma prediction samples of the video block by adding difference values ​​derived from the optical flow equation. In some embodiments of the method 1600, the affine merge mode includes generating a control point motion vector of a current codec unit of the video block based on motion information of spatially neighboring codec units of the current codec unit, and including in the bitstream an index indicating an affine merge candidate from a sub-block merge candidate list for the current codec unit. In some embodiments of the method 1600, the affine advanced motion vector prediction mode includes in the bitstream: (1) an affine flag at a codec unit level of the video block, indicating whether the affine advanced motion vector prediction mode is used, (2) a second flag, indicating whether 4-parameter affine or 6-parameter affine is used, (3) a control point motion vector prediction value index at the codec unit level, and (4) a difference between the control point motion vector of the current codec unit of the video block and a predicted control point motion vector corresponding to the control point motion vector.

[1033] Fig.17 17 is a flow chart of an example method 1700 of video processing. Operation 1702 includes performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video, wherein a rule specifies indicating a first syntax element in a video level higher than a picture level or a slice level, and wherein the first syntax element indicates whether the picture level or the slice level includes a quantization parameter increment.

[1034] In some embodiments of the method 1700, the video level is a sequence parameter set level or a picture parameter set level, and the first syntax element indicates whether the picture level or the slice level is enabled to include a luma quantization parameter increment or a chroma quantization parameter increment. In some embodiments of the method 1700, the rule specifies whether the luma quantization parameter increment is included in the picture header and / or the slice header based on the first syntax element indicating whether the luma quantization parameter increment is present. In some embodiments of the method 1700, the rule specifies that in response to the first syntax element indicating that the luma quantization parameter increment is not present in the picture level or the slice level, the luma quantization parameter increment is not allowed to be included in the picture header and the slice header. In some embodiments of the method 1700, the rule specifies that in response to the first syntax element indicating that the luma quantization parameter increment is not present in the picture level or the slice level, the luma quantization parameter increment is not allowed to be included in the picture header or the slice header. In some embodiments of the method 1700, the rule specifies that in response to the luma quantization parameter increment not being present in the picture header, the luma quantization parameter increment is inferred to have a specific value. In some embodiments of the method 1700, the rule provides that, in response to the luma quantization parameter increment not being present in the slice header, the luma quantization parameter increment is inferred to be a specific value. In some embodiments of the method 1700, the rule provides that the first syntax element controls whether the picture parameter set includes a flag that specifies whether the luma quantization parameter increment is included in the picture header or the slice header. In some embodiments of the method 1700, the rule provides that, in response to the first syntax element indicating that the luma quantization parameter increment is not present at the picture level or the slice level, the flag is excluded from the picture parameter set. In some embodiments of the method 1700, the rule provides that, in response to the flag not being present in the picture parameter set, the flag is inferred to have a specific value.

[1035] Fig.18 is a flow chart of an example method 1800 of video processing. Operation 1802 includes performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video, wherein a first rule specifies that a first flag in a first video level indicates whether one or more chroma quantization parameter offsets are included in the first video level, wherein the first video level is higher than the slice level, wherein a second rule specifies that a second flag in a second video level indicates whether one or more chroma quantization parameter offsets are included in a picture header or a slice header, and wherein the second video level is higher than the picture level.

[1036] In some embodiments of the method 1800, the second rule provides that a second flag in the picture parameter set indicates whether one or more chrominance quantization parameter offsets are included in a picture header or a slice header. In some embodiments of the method 1800, the second rule provides that, in response to the second flag indicating that the one or more chrominance quantization parameter offsets are included in the picture header, the one or more chrominance quantization parameter offsets are excluded from the slice header. In some embodiments of the method 1800, the second rule provides that, in response to the second flag indicating that the one or more chrominance quantization parameter offsets are excluded from the picture header, the one or more chrominance quantization parameter offsets are selectively included in the slice header. In some embodiments of the method 1800, in response to the one or more chrominance quantization parameter offsets being excluded from the picture header, the one or more chrominance quantization parameter offsets of the picture header are inferred to be specific values. In some embodiments of the method 1800, in response to the one or more chrominance quantization parameter offsets being excluded from the slice header, the one or more chrominance quantization parameter offsets of the slice header are inferred to be specific values. In some embodiments of the method 1800 , the second rule provides that the second flag further indicates whether the luma quantization parameter increment is included in a picture header or a slice header.

[1037] In some embodiments of the method 1800, the second rule provides that a second flag in the sequence parameter set and / or the picture parameter set indicates whether one or more chroma quantization parameter offsets are included in the picture header and / or the slice header. In some embodiments of the method 1800, the second rule provides that in response to the second flag indicating that one or more chroma quantization parameter offsets are not present in the picture level and the slice level, one or more chroma quantization parameter offsets are not allowed to be included in the picture header and the slice header. In some embodiments of the method 1800, the second rule provides that the second flag controls whether another flag is included in the picture parameter set, wherein the other flag indicates whether one or more chroma quantization parameter offsets are included in the picture level or the slice level. In some embodiments of the method 1800, the second rule provides that in response to the second flag indicating that one or more chroma quantization parameter offsets are excluded from the picture header or the slice header, the picture parameter set excludes another flag. In some embodiments of the method 1800, the second rule provides that in response to the absence of the other flag in the picture parameter set, it is inferred that the other flag has a specific value. In some embodiments of the method 1800, the second rule provides that the quantization parameter increment and the chroma quantization parameter offset are included in the same header. In some embodiments of the method 1800, the second rule provides that, in response to the quantization parameter increment being included in the picture header, one or more chrominance quantization parameter offsets are prohibited from being included in the slice header. In some embodiments of the method 1800, the second rule provides that, in response to the quantization parameter increment being included in the slice header, one or more chrominance quantization parameter offsets are prohibited from being included in the picture header.

[1038] Fig.19 1900A is a flow chart of an example method 1900A for video processing. Operation 1902A includes performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video, wherein the bitstream includes a first syntax element indicating a codec block subdivision value, and wherein the codec block subdivision value has a range according to a rule.

[1039] In some embodiments of the method 1900A, the rule specifies that the range of codec block subdivision values ​​for codec units in intra slices conveying cu_qp_delta_abs and cu_qp_delta_sign_flag is independent of a second syntax element in the bitstream that specifies the maximum hierarchical depth of codec units resulting from a multi-type tree partitioning of quadtree leaves in the slice. In some embodiments of the method 1900A, the rule specifies that the range is between 0 and 2*(CtbLog2SizeY-MinQtLog2SizeIntraY)+2*(CtbLog2SizeY-MinCbLog2SizeY), inclusive. In some embodiments of method 1900A, the rule specifies that the range is between 0 and 2*(CtbLog2SizeY-MinQtLog2SizeIntraY)+2*min(ph_max_mtt_hierarchy_depth_intra_slice_luma, CtbLog2SizeY-MinCbLog2SizeY) (including the end values), and ph_max_mtt_hierarchy_depth_intra_slice_luma is the second syntax element.

[1040] In some embodiments of the method 1900A, the rule specifies that the range of codec block subdivision values ​​for codec units in intra slices conveying cu_chroma_qp_offset_flag is independent of a second syntax element in the bitstream that specifies the maximum hierarchical depth of codec units resulting from a multi-type tree partitioning of quadtree leaves in the slice. In some embodiments of the method 1900A, the rule specifies that the range is between 0 and 2*(CtbLog2SizeY-MinQtLog2SizeIntraY)+2*(CtbLog2SizeY-MinCbLog2SizeY), inclusive. In some embodiments of the method 1900A, the rule specifies that the range is between 0 and 2*(CtbLog2SizeY-MinQtLog2SizeIntraY)+2*min(ph_max_mtt_hierarchy_depth_intra_slice_luma, CtbLog2SizeY-MinCbLog2SizeY) (inclusive), and ph_max_mtt_hierarchy_depth_intra_slice_luma is a second syntax element. In some embodiments of the method 1900A, the rule specifies that the range of codec block subdivision values ​​for codec units in intra slices for which cu_qp_delta_abs and cu_qp_delta_sign_flag are transmitted is independent of a second syntax element in the bitstream that specifies the maximum hierarchical depth of codec units resulting from a multi-type tree partitioning of quadtree leaves in a slice. In some embodiments of the method 1900A, the rule specifies that the range is between 0 and 2*(CtbLog2SizeY-MinQtLog2SizeInterY)+2*(CtbLog2SizeY-MinCbLog2SizeY) (including the end value). In some embodiments of the method 1900A, the rule specifies that the range is between 0 and 2*(CtbLog2SizeY-MinQtLog2SizeIntraY)+2*min(ph_max_mtt_hierarchy_depth_inter_slice, CtbLog2SizeY-MinCbLog2SizeY) (including the end value), and ph_max_mtt_hierarchy_depth_inter_slice is the second syntax element.

[1041] In some embodiments of the method 1900A, the rule specifies that the range of codec block subdivision values ​​for codec units in intra slices conveying cu_chroma_qp_offset_flag is independent of a second syntax element in the bitstream that specifies the maximum hierarchical depth of codec units resulting from a multi-type tree partitioning of quadtree leaves in the slice. In some embodiments of the method 1900A, the rule specifies that the range is between 0 and 2*(CtbLog2SizeY-MinQtLog2SizeInterY)+2*(CtbLog2SizeY-MinCbLog2SizeY), inclusive. In some embodiments of method 1900A, the rule specifies that the range is between 0 and 2*(CtbLog2SizeY-MinQtLog2SizeIntraY)+2*min(ph_max_mtt_hierarchy_depth_inter_slice, CtbLog2SizeY-MinCbLog2SizeY) (inclusive), and ph_max_mtt_hierarchy_depth_inter_slice is the second syntax element.

[1042] In some embodiments of methods 700-1900A, performing the conversion includes encoding the video into a bitstream. In some embodiments of methods 700-1900A, performing the conversion includes generating a bitstream from the video, and the method also includes storing the bitstream in a non-transitory computer-readable recording medium. In some embodiments of methods 700-1900A, performing the conversion includes decoding the video from the bitstream. In some embodiments, the video decoding device includes a processor configured to implement the operation of methods 700-1900A. In some embodiments, a computer program product having computer instructions stored thereon, when executed by a processor, the instructions cause the processor to implement the operation of methods 700-1900A. In some embodiments, a non-transitory computer-readable storage medium storing a bitstream generated according to the operation of methods 700-1900A. In some embodiments, a non-transitory computer-readable storage medium stores instructions that cause the processor to implement the operation of methods 700-1900A. In some embodiments, a method for generating a bitstream includes: generating a bitstream of a video according to the operations of methods 700-1900A, and storing the bitstream on a computer-readable program medium. In some embodiments, a bitstream generated according to a method, apparatus, disclosed method or system described in this document.

[1043] In this document, the term "video processing" may refer to video encoding, video decoding, video compression, or video decompression. For example, during the conversion from a pixel representation of a video to a corresponding bitstream representation, a video compression algorithm may be applied, and vice versa. As defined by the syntax, the bitstream representation of the current video block may correspond to bits that are co-located or scattered at different positions within the bitstream, for example. For example, a macroblock may be encoded based on the error residual values ​​of the transform and the codec and also using bits in the header and other fields in the bitstream. In addition, during the conversion, the decoder may parse the bitstream based on this determination, knowing that some fields may or may not exist, as described in the above solution. Similarly, the encoder may determine whether to include or not include certain syntax fields, and generate the codec representation accordingly by including or excluding the syntax fields from the codec representation.

[1044] The disclosure and other schemes, examples, embodiments, modules and functional operations described in this document may be implemented in digital electronic circuits or in computer software, firmware or hardware, containing the structures disclosed in this document and the equivalents of their structures, or a combination of one or more of them. The disclosed and other embodiments may 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 device or for controlling the operation of a data processing device. The computer-readable medium may be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composite that affects a machine-readable propagable signal, or a combination of one or more thereof. The term "data processing device" encompasses all devices, equipment and machines for processing data, including, for example, a programmable processor, a computer or multiple processors or computers. In addition to hardware, the device may also include code that creates an execution environment for the computer program in question, for example, code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. A propagation signal is an artificially generated signal, for example, a machine-generated electrical, optical or electromagnetic signal, which is generated to encode information for transmission to a suitable receiver device.

[1045] A computer program (also referred to as a program, software, software application, script or code) can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including stand-alone 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 stores other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple collaborative files (e.g., files storing one or more modules, subroutines or code portions). A computer program can be deployed to execute on one computer or on multiple computers, which are located at one site or distributed across multiple sites and interconnected by a communication network.

[1046] The processes and logic flows described in this document may be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows may also be performed by special purpose logic circuits (e.g., field programmable gate arrays (FPGAs) or application specific integrated circuits (ASICs)), and the apparatus may be implemented as special purpose logic circuits (e.g., FPGAs or ASICs).

[1047] Processors suitable for the execution of computer programs include, for example, both general-purpose and special-purpose microprocessors, and any one or more processors of any type of digital computer. Typically, the processor will receive instructions and data from a read-only memory or a random access memory or both. The basic elements of a computer are a processor for performing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include one or more mass storage devices (such as magnetic, magneto-optical disks or optical disks) for storing data, or be operably coupled to receive data from a mass storage device (such as magnetic, magneto-optical disks or optical disks) or transfer data to a mass storage device (such as magnetic, magneto-optical disks or optical disks), or both. However, a computer does not have to have such devices. Computer-readable media suitable for storing computer program instructions and data contain all forms of non-volatile memory, media and memory devices, including, for example, semiconductor memory devices (such as EPROM, EEPROM and flash memory devices); disks (such as internal hard disks or removable disks); magneto-optical disks; and CD ROM and DVD-ROM disks. The processor and memory can be supplemented by special-purpose logic circuits, or incorporated in special-purpose logic circuits.

[1048] Although this patent document contains many details, these details should not be interpreted as limitations on any subject matter or the scope of protection that can be claimed, but as descriptions of features of specific embodiments specified in specific technologies. In this patent document, certain features described in the context of separate embodiments may also be implemented in combination in a single embodiment. On the contrary, the various features described in the context of a single embodiment may also be implemented in multiple embodiments, respectively, or in various suitable sub-combinations. In addition, although features may be described as working in certain combinations and even initially required in the same manner as described above, one or more features from the claimed combination may be removed from the combination in some cases, and the claimed combination may be directed to a sub-combination or a variation of the sub-combination.

[1049] Similarly, although operations are depicted in a particular order in the drawings, this should not be understood as requiring that such operations be performed in the particular order shown or in the sequential order shown, or that all illustrated operations be performed, in order to achieve the desired results. Furthermore, the separation of various system components in the embodiments described in this patent document should not be understood as requiring such separation in all embodiments.

[1050] Only a few implementations and examples are described, and other implementations, enhancements, and variations may be made based on what is described and illustrated in this patent document.

Claims

1. A method for processing video data, comprising: For conversion between a current video block of a video and a bitstream of the video, determining a size of a prediction block corresponding to the current video block according to a rule; as well as performing said converting based on said determining, Wherein, the affine merge mode is enabled for the current video block, wherein the rule provides for determining a first size of the prediction block in response to whether a prediction refinement technique using optical flow is enabled for the current video block, and wherein the current video block has a second size, wherein a second width and a second height of the second size of the current video block are indicated by M and N, respectively, and M and N are integers greater than or equal to 0, The prediction samples of the prediction block are represented as predSamplesLX[xL][yL], and wherein, in a case where the prediction refinement technique using optical flow is enabled for the current video block, a first width and a first height of a first size of the prediction block are indicated by (M+M0) and (N+N0), respectively, and wherein M0 and N0 are equal to 2, xL is between 0 and M+1, including 0 and M+1, and yL is between 0 and N+1, including 0 and N+1, and The predicted samples predSamplesLX[xL][yL] are derived by calling a luma integer sample acquisition process when one or more of the conditions are true, and the predicted samples predSamplesLX[xL][yL] are derived by calling a luma sample 8-tap interpolation filtering process when all of the conditions are false, wherein the conditions include: xL is equal to 0, xL is equal to M+1, yL is equal to 0, or yL is equal to N+1.

2. The method according to claim 1, wherein: The prediction refinement utilization flag indicating whether to utilize the prediction refinement technique using optical flow controls the values ​​of M0 and N0.

3. The method according to claim 2, wherein: The values ​​of M0 and N0 are determined independently of the affine flag, and The affine flag is inter_affine_flag, and the affine flag is used to indicate whether to apply the affine motion vector prediction mode.

4. The method according to claim 3, wherein: For a video block to which the affine motion vector prediction mode is applied, a size of a prediction block of the video block is equal to the first size.

5. The method according to claim 1, wherein: The affine merge mode includes generating a control point motion vector by selecting an affine merge candidate from a sub-block merge candidate list constructed based on motion information of spatially adjacent codec units using a merge index.

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

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

8. 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: For conversion between a current video block of a video and a bitstream of the video, determining a size of a prediction block corresponding to the current video block according to a rule; and performing said converting based on said determining, Wherein, the affine merge mode is enabled for the current video block, wherein the rule provides for determining a first size of the prediction block in response to whether a prediction refinement technique using optical flow is enabled for the current video block, and wherein the current video block has a second size, The second width and the second height of the second size of the current video block are indicated by M and N, respectively, and M and N are integers greater than or equal to 0, The prediction samples of the prediction block are represented as predSamplesLX[xL][yL], and wherein, in a case where the prediction refinement technique using optical flow is enabled for the current video block, a first width and a first height of a first size of the prediction block are indicated by (M+M0) and (N+N0), respectively, and wherein M0 and N0 are equal to 2, xL is between 0 and M+1, including 0 and M+1, and yL is between 0 and N+1, including 0 and N+1, and The predicted samples predSamplesLX[xL][yL] are derived by calling a luma integer sample acquisition process when one or more of the conditions are true, and the predicted samples predSamplesLX[xL][yL] are derived by calling a luma sample 8-tap interpolation filtering process when all of the conditions are false, wherein the conditions include: xL is equal to 0, xL is equal to M+1, yL is equal to 0, or yL is equal to N+1.

9. The device according to claim 8, wherein: The prediction refinement flag indicating whether to use the prediction refinement technique using optical flow controls the values ​​of M0 and N0, The values ​​of M0 and N0 are determined independently of the affine sign. The affine flag is inter_affine_flag, and the affine flag is used to indicate whether to apply the affine motion vector prediction mode. Wherein, for a video block to which the affine motion vector prediction mode is applied, the size of the prediction block of the video block is equal to the first size, and The affine merge mode includes generating a control point motion vector by selecting an affine merge candidate from a sub-block merge candidate list constructed based on motion information of spatially adjacent coding units using a merge index.

10. A non-transitory computer-readable storage medium storing instructions that cause a processor to: For conversion between a current video block of a video and a bitstream of the video, determining a size of a prediction block corresponding to the current video block according to a rule; and performing said converting based on said determining, in, Enable affine merge mode for the current video block, wherein the rule provides for determining a first size of the prediction block in response to whether a prediction refinement technique using optical flow is enabled for the current video block, and wherein the current video block has a second size, The second width and the second height of the second size of the current video block are indicated by M and N, respectively, and M and N are integers greater than or equal to 0, The prediction samples of the prediction block are represented as predSamplesLX[xL][yL], and wherein, in a case where the prediction refinement technique using optical flow is enabled for the current video block, a first width and a first height of a first size of the prediction block are indicated by (M+M0) and (N+N0), respectively, and wherein M0 and N0 are equal to 2, xL is between 0 and M+1, including 0 and M+1, and yL is between 0 and N+1, including 0 and N+1, and The predicted samples predSamplesLX[xL][yL] are derived by calling a luma integer sample acquisition process when one or more of the conditions are true, and the predicted samples predSamplesLX[xL][yL] are derived by calling a luma sample 8-tap interpolation filtering process when all of the conditions are false, wherein the conditions include: xL is equal to 0, xL is equal to M+1, yL is equal to 0, or yL is equal to N+1.

11. The non-transitory computer-readable storage medium of claim 10, wherein: The prediction refinement flag indicating whether to use the prediction refinement technique using optical flow controls the values ​​of M0 and N0, The values ​​of M0 and N0 are determined independently of the affine sign. The affine flag is inter_affine_flag, and the affine flag is used to indicate whether to apply the affine motion vector prediction mode. Wherein, for a video block to which the affine motion vector prediction mode is applied, the size of the prediction block of the video block is equal to the first size, and The affine merge mode includes generating a control point motion vector by selecting an affine merge candidate from a sub-block merge candidate list constructed based on motion information of spatially adjacent coding units using a merge index.

12. A non-transitory computer-readable storage medium storing a bitstream of a video, the bitstream being generated by a method performed by a video processing device, wherein the method comprises: For a current video block of a video, determining a size of a prediction block corresponding to the current video block according to a rule; as well as generating the bitstream based on the determination, Wherein, the affine merge mode is enabled for the current video block, wherein the rule provides for determining a first size of the prediction block in response to whether a prediction refinement technique using optical flow is enabled for the current video block, and wherein the current video block has a second size, The second width and the second height of the second size of the current video block are indicated by M and N, respectively, and M and N are integers greater than or equal to 0, The prediction samples of the prediction block are represented as predSamplesLX[xL][yL], and wherein, in a case where the prediction refinement technique using optical flow is enabled for the current video block, a first width and a first height of a first size of the prediction block are indicated by (M+M0) and (N+N0), respectively, and wherein M0 and N0 are equal to 2, xL is between 0 and M+1, including 0 and M+1, and yL is between 0 and N+1, including 0 and N+1, and The predicted samples predSamplesLX[xL][yL] are derived by calling a luma integer sample acquisition process when one or more of the conditions are true, and the predicted samples predSamplesLX[xL][yL] are derived by calling a luma sample 8-tap interpolation filtering process when all of the conditions are false, wherein the conditions include: xL is equal to 0, xL is equal to M+1, yL is equal to 0, or yL is equal to N+1.

13. The non-transitory computer-readable storage medium of claim 12, wherein: The prediction refinement flag indicating whether to use the prediction refinement technique using optical flow controls the values ​​of M0 and N0, The values ​​of M0 and N0 are determined independently of the affine sign. The affine flag is inter_affine_flag, and the affine flag is used to indicate whether to apply the affine motion vector prediction mode. Wherein, for a video block to which the affine motion vector prediction mode is applied, the size of the prediction block of the video block is equal to the first size, and The affine merge mode includes generating a control point motion vector by selecting an affine merge candidate from a sub-block merge candidate list constructed based on motion information of spatially adjacent coding units using a merge index.

14. A method for storing a bit stream of a video, comprising: For a current video block of a video, determining a size of a prediction block corresponding to the current video block according to a rule; generating the bitstream based on the determination; as well as storing the bitstream in a non-transitory computer-readable storage medium, Wherein, the affine merge mode is enabled for the current video block, wherein the rule provides for determining a first size of the prediction block in response to whether a prediction refinement technique using optical flow is enabled for the current video block, and wherein the current video block has a second size, The second width and the second height of the second size of the current video block are indicated by M and N, respectively, and M and N are integers greater than or equal to 0, The prediction samples of the prediction block are represented as predSamplesLX[xL][yL], and wherein, in a case where the prediction refinement technique using optical flow is enabled for the current video block, a first width and a first height of a first size of the prediction block are indicated by (M+M0) and (N+N0), respectively, and wherein M0 and N0 are equal to 2, xL is between 0 and M+1, including 0 and M+1, and yL is between 0 and N+1, including 0 and N+1, and The predicted samples predSamplesLX[xL][yL] are derived by calling a luma integer sample acquisition process when one or more of the conditions are true, and the predicted samples predSamplesLX[xL][yL] are derived by calling a luma sample 8-tap interpolation filtering process when all of the conditions are false, wherein the conditions include: xL is equal to 0, xL is equal to M+1, yL is equal to 0, or yL is equal to N+1.

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