Patent Application
20240073419
This patent document relates to video coding techniques, devices and systems.
Currently, efforts are underway to improve the performance of current video codec technologies to provide better compression ratios or provide video coding and decoding schemes that allow for lower complexity or parallelized implementations. Industry experts have recently proposed several new video coding tools and tests are currently underway for determining their effectivity.
Devices, systems and methods related to digital video coding, and specifically, to management of motion vectors are described. The described methods may be applied to existing video coding standards (e.g., High Efficiency Video Coding (HEVC) or Versatile Video Coding (VVC)) and future video coding standards or video codecs.
In one representative aspect, the disclosed technology may be used to provide a method for video processing. This method includes performing a conversion between a video unit of a video and a bitstream of the video according to a rule, where the rule specifies that whether a cross-component adaptive loop filter (CC-ALF) mode and an adaptive loop filter (ALF) mode are enabled for coding the video unit are indicated in the bitstream in a mutually independent manner.
In another representative aspect, the disclosed technology may be used to provide a method for video processing. This method includes performing a conversion between a video unit of a chroma component a video and a bitstream of the video, wherein the bitstream conforms to a format rule, where the format rule specifies that the bitstream includes a syntax element indicating whether a cross-component filter for the chroma component is enabled for all slices associated with a picture header only when: a value for a chroma array type is not equal to zero, or a color format of the video is not 4:0:0.
In another representative aspect, the disclosed technology may be used to provide a method for video processing. This method includes performing a conversion between a video unit and a coded representation of the video unit, wherein, during the conversion, a deblocking filter is used on boundaries of the video unit such that when a chroma quantization parameter (QP) table is used to derive parameters of the deblocking filter, processing by the chroma QP table is performed on individual chroma QP values.
In another representative aspect, the disclosed technology may be used to provide another method for video processing. This method includes performing a conversion between a video unit and a coded representation of the video unit, wherein, during the conversion, a deblocking filter is used on boundaries of the video unit such that chroma QP offsets are used in the deblocking filter, wherein the chroma QP offsets are at picture/slice/tile/brick/subpicture level.
In another representative aspect, the disclosed technology may be used to provide another method for video processing. This method includes performing a conversion between a video unit and a coded representation of the video unit, wherein, during the conversion, a deblocking filter is used on boundaries of the video unit such that chroma QP offsets are used in the deblocking filter, wherein information pertaining to a same luma coding unit is used in the deblocking filter and for deriving a chroma QP offset.
In another representative aspect, the disclosed technology may be used to provide another method for video processing. This method includes performing a conversion between a video unit and a coded representation of the video unit, wherein, during the conversion, a deblocking filter is used on boundaries of the video unit such that chroma QP offsets are used in the deblocking filter, wherein an indication of enabling usage of the chroma QP offsets is signalled in the coded representation.
In another representative aspect, the disclosed technology may be used to provide another method for video processing. This method includes performing a conversion between a video unit and a coded representation of the video unit, wherein, during the conversion, a deblocking filter is used on boundaries of the video unit such that chroma QP offsets are used in the deblocking filter, wherein the chroma QP offsets used in the deblocking filter are identical of whether joint coding of chroma residuals (JCCR) coding method is applied on a boundary of the video unit or a method different from the JCCR coding method is applied on the boundary of the video unit.
In another representative aspect, the disclosed technology may be used to provide another method for video processing. This method includes performing a conversion between a video unit and a coded representation of the video unit, wherein, during the conversion, a deblocking filter is used on boundaries of the video unit such that chroma QP offsets are used in the deblocking filter, wherein a boundary strength (BS) of the deblocking filter is calculated without comparing reference pictures and/or a number of motion vectors (MVs) associated with the video unit at a P side boundary with reference pictures of the video unit at a Q side boundary.
In another example aspect, another method of video processing is disclosed. The method includes determining, for a conversion between a video unit of a component of a video and a coded representation of the video, a size of a quantization group for the video unit, based on a constraint rule that specifies that the size must be larger than K, where K is a positive number and performing the conversion based on the determining.
In another example aspect, another method of video processing is disclosed. The method includes performing a conversion between a video unit of a video and a bitstream of the video according to a rule, wherein the rule specifies whether the bitstream includes at least one of a control flag of a chroma block-based delta pulse code modulation (BDPCM) mode, a palette mode, or an adaptive color transform (ACT) mode is based on a value of a chroma array type of the video.
Further, in a representative aspect, an apparatus in a video system comprising a processor and a non-transitory memory with instructions thereon is disclosed. The instructions upon execution by the processor, cause the processor to implement any one or more of the disclosed methods.
Additionally, in a representative aspect, a video decoding apparatus comprising a processor configured to implement any one or more of the disclosed methods.
In another representative aspect, a video encoding apparatus comprising a processor configured to implement any one or more of the disclosed methods.
Also, a computer program product stored on a non-transitory computer readable media, the computer program product including program code for carrying out any one or more of the disclosed methods is disclosed.
The above and other aspects and features of the disclosed embodiments are described in greater detail in the drawings, the description and the claims.
Video coding standards have evolved primarily through the development of the well-known International Telecommunication Union (ITU) Telecommunication Standardization Sector (ITU-T) and International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC) standards. The ITU-T produced H.261 and H.263, ISO/IEC produced Motion Picture Experts Group (MPEG)-1 and MPEG-4 Visual, and the two organizations jointly produced the H.262/MPEG-2 Video and H.264/MPEG-4 Advanced Video Coding (AVC) and H.265/HEVC standards. Since H.262, the video coding standards are based on the hybrid video coding structure wherein temporal prediction plus transform coding are utilized. To explore the future video coding technologies beyond HEVC, Joint Video Exploration Team (JVET) was founded by VCEG and MPEG jointly in 2015. Since then, many new methods have been adopted by JVET and put into the reference software named Joint Exploration Model (JEM). In April 2018, the Joint Video Expert Team (JVET) between VCEG (Q6/16) and ISO/IEC JTC1 SC29/WG11 (MPEG) was created to work on the VVC standard targeting at 50% bitrate reduction compared to HEVC.
A deblocking filter process is performed for each coding unit (CU) in the same order as the decoding process. First, vertical edges are filtered (horizontal filtering), then horizontal edges are filtered (vertical filtering). Filtering is applied to 8×8 block boundaries which are determined to be filtered, for both luma and chroma components. 4×4 block boundaries are not processed in order to reduce the complexity.
Three kinds of boundaries may be involved in the filtering process: CU boundary, transform unit (TU) boundary and PU boundary. CU boundaries, which are outer edges of CU, are always involved in the filtering since CU boundaries are always also TU boundary or PU boundary. When PU shape is 2N×N (N>4) and residual quadtree (RQT) depth is equal to 1, TU boundary at 8×8 block grid and PU boundary between each PU inside CU are involved in the filtering. One exception is that when the PU boundary is inside the TU, the boundary is not filtered.
Boundary strength (Bs) reflects how strong filtering is needed for the boundary. If Bs is large, strong filtering should be considered.
Let P and Q be defined as blocks which are involved in the filtering, where P represents the block located in left (vertical edge case) or above (horizontal edge case) side of the boundary and Q represents the block located in right (vertical edge case) or above (horizontal edge case) side of the boundary.
Bs is calculated on a 4×4 block basis, but it is re-mapped to an 8×8 grid. The maximum of the two values of Bs which correspond to 8 pixels consisting of a line in the 4×4 grid is selected as the Bs for boundaries in the 8×8 grid.
In order to reduce a line buffer memory requirement, only for a CTU boundary, information in every second block (4×4 grid) in left or above side is re-used as depicted in
Threshold values β and tC which involving in filter on/off decision, strong and weak filter selection and weak filtering process are derived based on luma quantization parameter of P and Q blocks, QPp and QPQ, respectively. Q used to derive β and tC is calculated as follows. Q=((QPP+QPQ+1)>>1).
A variable β is derived as shown in Table 1, based on Q. If Bs is greater than 1, the variable tC is specified as Table 1 with Clip3(0, 55, Q+2) as input. Otherwise (BS is equal or less than 1), the variable tC is specified as Table 1 with Q as input.
2.1.3. Filter on/Off Decision for 4 Lines
Filter on/off decision is done for four lines as a unit.
If dp0+dq0+dp3+dq3<3, filtering for the first four lines is turned on and strong/weak filter selection process is applied. Each variable is derived as follows.
dp0=|p2,0−2*p1,0+p0,0,dp3=p2,3−2*p1,3+p0,3|,dp4=|p2,4−2*p1,4+p0,4|,dp7=|p2,7−2*p1,7+p0,7|
dq0=|q2,0−2*q1,0+q0,0|,dq3=q2,3−2*q1,3+q0,3,dq4=q2,4−2*q1,4+q0,4,dq7=|q2,7−2*q1,7+q0,7|
If the condition is not met, no filtering is done for the first 4 lines. Additionally, if the condition is met, dE, dEp1 and dEp2 are derived for weak filtering process. The variable dE is set equal to 1. If dp0+dp3<(β+(β>>1))>>3, the variable dEp1 is set equal to 1. If dq0+dq3<(β+(β>>1))>>3, the variable dEq1 is set equal to 1.
For the second four lines, decision is made in a same fashion with above.
After the first four lines are determined to filtering on in filter on/off decision, if following two conditions are met, strong filter is used for filtering of the first four lines. Otherwise, weak filter is used for filtering. Involving pixels are same with those used for filter on/off decision as depicted in
2*(dp0+dq0)<(β>>2),|p30−p00|+q00−q30|<(β>>3) and p00−q00|<(5*tC+1)>>1 1)
2*(dp3+dq3)<(β>>2),|p33−p03|+q03−q33|<(β>>3) and |p03−q03|<(5*tC+1)>>1 2)
As a same fashion, if following two conditions are met, strong filter is used for filtering of the second 4 lines. Otherwise, weak filter is used for filtering.
2*(dp4+dq4)<(β>>2),|p34−p04|+|q04−q34|<(β>>3) and |p04−q04|<(5*tC+1)>>1 1)
2*(dp7+dq7)<(β>>2),|p37−p07|+|q07−q37|<(β>>3) and |p07−q07|<(5*tC+1)>>1 2)
For strong filtering, filtered pixel values are obtained by following equations. It is worth to note that three pixels are modified using four pixels as an input for each P and Q block, respectively.
p
0′=(p2+2*p1+2*p0+2*q0+q1+4)>>3
q
0′=(p1+2*p0+2*q0+2*q1+q2+4)>>3
p
1′=(p2+p1+p0+q0+2)>>2
q
1′=(p0+q0+q1+q2+2)>>2
p
2′=(2*p3+3*p2+p1+p0+q0+4)>>3
q
2′=(p0+q0+q1+3*q2+2*q3+4)>>3
Let's define Δ as follows.
Δ=(9*(q0−p0)−3*(q1−p1)+8)>>4
When abs(Δ) is less than tC*10,
Δ=Clip3(−tC,tC,Δ)
p
0′=Clip1Y(p0+Δ)
q
0′=Clip1Y(q0−Δ)
If dEp1 is equal to 1,
Δp=Clip3(−(tC>>1),tC>>1,(((p2+p0+1)>>1)−p1+Δ)>>1)
p
1′=Clip1Y(p1+Δp)
If dEq1 is equal to 1,
Δq=Clip3(−(tC>>1),tC>>1,(((q2+q0+1)>>1)−q1−Δ)>>1)
q
1′=Clip1Y(q1+Δq)
It is worth to note that a maximum of two pixels are modified using three pixels as an input for each P and Q block, respectively.
Bs of chroma filtering is inherited from luma. If Bs>1 or if coded chroma coefficient existing case, chroma filtering is performed. No other filtering decision is there. And only one filter is applied for chroma. No filter selection process for chroma is used. The filtered sample values p0′ and q0′ are derived as follows.
Δ=Clip3(−tC,tC,((((q0−p0)<<2)+p1−q1+4)>>3))
p
0′=Clip1C(p0+Δ)
q
0′=Clip1C(q0−Δ)
In the virtual transport medium (VTM) 6, deblocking filtering process may be similar to those in HEVC. However, some modifications may be added, such as, for example:
In HEVC, the filter strength of the deblocking filter is controlled by the variables β and tC which are derived from the averaged quantization parameters qPL. In the VTM6, deblocking filter controls the strength of the deblocking filter by adding offset to qPL according to the luma level of the reconstructed samples if the sequence parameter set (SPS) flag of this method is true. The reconstructed luma level (LL) is derived as follow:
LL=((p0,0+p0,3+q0,0+q0,3)>>2)/(1<<bitDepth) (3-1)
where, the sample values pi,k and qi,k with i=0 . . . 3 and k=0 and 3 are derived as shown in equation 3-1. Then LL is used to decide the offset qpOffset based on the threshold signalled in SPS. After that, the qPL, which is derived as follows, is employed to derive the β and tC.
qPL=((QpQ+QpP+1)>>1)+qpOffset (3-2)
where QpQ and QpP denote the quantization parameters of the coding units containing the sample q0,0 and p0,0, respectively. In the current VVC, this method may only be applied on the luma deblocking process.
HEVC uses an 8×8 deblocking grid for both luma and chroma. In VTM6, deblocking on a 4×4 grid for luma boundaries was introduced to handle blocking artifacts from rectangular transform shapes. Parallel friendly luma deblocking on a 4×4 grid is achieved by restricting the number of samples to be deblocked to 1 sample on each side of a vertical luma boundary where one side has a width of 4 or less or to 1 sample on each side of a horizontal luma boundary where one side has a height of 4 or less.
An example of a detailed boundary strength derivation is shown in Table 2. The conditions in Table 2 may be checked sequentially.
The proposal uses a bilinear filter when samples at either one side of a boundary belong to a large block. A sample belonging to a large block is defined as when the width>=32 for a vertical edge, and when height>=32 for a horizontal edge.
The bilinear filter is listed below.
Block boundary samples pi for i=0 to Sp−1 and qi for j=0 to Sq−1 (pi and qi follow the definitions in HEVC deblocking described above) are then replaced by linear interpolation as follows:
p
i′=(fi*Middles,t+(64−fi)*Ps+32)>>6),clipped to pi±tcPDi
q
j′=(gj*Middles,t+(64−gj)*Qs+32)>>6),clipped to qj±tcPDj
where tcPDi and tcPDj term is a position dependent clipping described in Section 2.2.5 and gj, fi, Middles,t, Ps and Qs are given below:
The deblocking decision process is described in this sub-section.
Wider-stronger luma filter is filters are used only if all of the Condition1, Condition2 and Condition 3 are TRUE.
The condition 1 is the “large block condition.” This condition detects whether the samples at P-side and Q-side belong to large blocks, which are represented by the variable bSidePisLargeBlk and bSideQisLargeBlk respectively. The bSidePisLargeBlk and bSideQisLargeBlk are defined as follows.
bSidePisLargeBlk=((edge type is vertical and p0 belongs to CU with width>=32)∥(edge type is horizontal and p0 belongs to CU with height>=32))?TRUE:FALSE
bSideQisLargeBlk=((edge type is vertical and q0 belongs to CU with width>=32)∥(edge type is horizontal and q0 belongs to CU with height>=32))?TRUE:FALSE
Based on bSidePisLargeBlk and bSideQisLargeBlk, the condition 1 is defined as follows.
Condition1=(bSidePisLargeBlk∥bSidePisLargeBlk)?TRUE:FALSE
Next, if Condition 1 is true, the condition 2 will be further checked. First, the following variables are derived:
Then the condition 2 is defined as follows.
Condition2=(d<β)?TRUE:FALSE
Where d=dp0+dq0+dp3+dq3, as shown in section 2.1.4.
If Condition1 and Condition2 are valid it is checked if any of the blocks uses subblocks:
Finally, if both the Condition 1 and Condition 2 are valid, the proposed deblocking method will check the condition 3 (the large block Strong filter condition), which is defined as follows.
In the Condition3 StrongFilterCondition, the following variables are derived:
As in HEVC derive, StrongFilterCondition=(dpq is less than ((β>>2), sp3+sq3 is less than (3*β>>5), and Abs(p0−q0) is less than (5*tC+1)>>1)?TRUE:FALSE
The following strong deblocking filter for chroma is defined:
p
2′=(3*p3+2*p2+p1+p0+q0+4)>>3
p
1′=(2*p3+p2+2*p1+p0+q0+q1+4)>>3
p
0′=(p3+p2+p1+2*p0+q0+q1+q2+4)>>3
The proposed chroma filter performs deblocking on a 4×4 chroma sample grid.
The above chroma filter performs deblocking on a 8×8 chroma sample grid. The chroma strong filters are used on both sides of the block boundary. Here, the chroma filter is selected when both sides of the chroma edge are greater than or equal to 8 (in unit of chroma sample), and the following decision with three conditions are satisfied. The first one is for decision of boundary strength as well as large block. The second and third one are basically the same as for HEVC luma decision, which are on/off decision and strong filter decision, respectively.
The proposal also introduces a position dependent clipping tcPD which is applied to the output samples of the luma filtering process involving strong and long filters that are modifying 7, 5 and 3 samples at the boundary. Assuming quantization error distribution, it is proposed to increase clipping value for samples which are expected to have higher quantization noise, thus expected to have higher deviation of the reconstructed sample value from the true sample value.
For each P or Q boundary filtered with proposed asymmetrical filter, depending on the result of decision making process described in Section 2.2, position dependent threshold table is selected from Tc7 and Tc3 tables that are provided to decoder as a side information:
Tc7={6,5,4,3,2,1,1};
Tc3={6,4,2};
tcPD=(SP==3)?Tc3:Tc7;
tcQD=(SQ==3)?Tc3:Tc7;
For the P or Q boundaries being filtered with a short symmetrical filter, a position dependent threshold of lower magnitude is applied:
Tc3={3,2,1};
The following defining the threshold, filtered p′i and q′i sample values are clipped according to tcP and tcQ clipping values:
p″
i=clip3(p′i+tcPi,p′i−tcPi,p′i);
q″
j=clip3(q′j+tcQj,q′j−tcQj,q′j)
where p′i and q′i are filtered sample values, p″i and q″j are output sample value after the clipping and tcPi tcPi are clipping thresholds that are derived from the VVC tc parameter and tcPD and tcQD. Term clip3 is a clipping function as it is specified in VVC.
To enable parallel friendly deblocking using both long filters and sub-block deblocking the long filters is restricted to modify at most 5 samples on a side that uses sub-block deblocking (AFFINE or advanced temporal motion vector prediction (ATMVP)) as shown in the luma control for long filters. Additionally, the sub-block deblocking is adjusted such that that sub-block boundaries on an 8×8 grid that are close to a CU or an implicit TU boundary is restricted to modify at most two samples on each side.
Following applies to sub-block boundaries that not are aligned with the CU boundary.
Where edge equal to 0 corresponds to CU boundary, edge equal to 2 or equal to orthogonalLength-2 corresponds to sub-block boundary 8 samples from a CU boundary etc. Where implicit TU is true if implicit split of TU is used.
Filtering of horizontal boundary is limiting Sp=3 for luma, Sp=1 and Sq=1 for chroma, when the horizontal boundary is aligned with the CTU boundary.
HEVC enables deblocking of a prediction unit boundary when the difference in at least one motion vector component between blocks on respective side of the boundary is equal to or larger than a threshold of 1 sample. In VTM6, a threshold of a half luma sample is introduced to also enable removal of blocking artifacts originating from boundaries between inter prediction units that have a small difference in motion vectors.
In VTM6, when a CU is coded in merge mode, if the CU contains at least 64 luma samples (that is, CU width times CU height is equal to or larger than 64), and if both CU width and CU height are less than 128 luma samples, an additional flag is signalled to indicate if the combined inter/intra prediction (CIIP) mode is applied to the current CU. As its name indicates, the CIIP prediction combines an inter prediction signal with an intra prediction signal. The inter prediction signal in the CIIP mode Pinter is derived using the same inter prediction process applied to regular merge mode; and the intra prediction signal Pintra is derived following the regular intra prediction process with the planar mode. Then, the intra and inter prediction signals are combined using weighted averaging, where the weight value is calculated depending on the coding modes of the top and left neighbouring blocks as follows:
The CIIP prediction is formed as follows:
P
CIIP=((4−wt)*Pinter+wt*Pintra+2)>>2
A chroma Quantization Parameter (QP) table design presented in JVET-00650 was adopted into VVC. It proposes a signalling mechanism for chroma QP tables, which enables that it is flexible to provide encoders the opportunity to optimize the table for Standard Dynamic Range (SDR) and High Dynamic Range (HDR) content. It supports for signalling the tables separately for Cb and Cr components. The proposed mechanism signals the chroma QP table as a piece-wise linear function.
As in HEVC, the residual of a block can be coded with transform skip mode. To avoid the redundancy of syntax coding, the transform skip flag is not signalled when the CU level MTS_CU_flag is not equal to zero. The block size limitation for transform skip is the same to that for Multiple Transform Selection (MTS) in Joint Exploration Model (JEM)4, which indicate that transform skip is applicable for a CU when both block width and height are equal to or less than 32. Note that implicit MTS transform is set to discrete cosine transform (DCT)2 when Low Frequency Non-Separable Transform (LFNST) or Matrix Weighted Intra Prediction (MIP) is activated for the current CU. Also the implicit MTS can be still enabled when MTS is enabled for inter coded blocks.
In addition, for transform skip block, minimum allowed Quantization Parameter (QP) is defined as 6*(internalBitDepth−inputBitDepth)+4.
VVC Draft 6 supports a mode where the chroma residuals are coded jointly. The usage (activation) of a joint chroma coding mode is indicated by a TU-level flag tu_joint_cbcr_residual_flag and the selected mode is implicitly indicated by the chroma coded block flag (CBFs). The flag tu_joint_cbcr_residual_flag is present if either or both chroma CBFs for a TU are equal to 1. In the PPS and slice header, chroma QP offset values are signalled for the joint chroma residual coding mode to differentiate from the usual chroma QP offset values signalled for regular chroma residual coding mode. These chroma QP offset values are used to derive the chroma QP values for those blocks coded using the joint chroma residual coding mode. When a corresponding joint chroma coding mode (modes 2 in Table 3) is active in a TU, this chroma QP offset is added to the applied luma-derived chroma QP during quantization and decoding of that TU. For the other modes (modes 1 and 3 in Table 3), the chroma QPs are derived in the same way as for conventional Cb or Cr blocks. The reconstruction process of the chroma residuals (resCb and resCr) from the transmitted transform blocks is depicted in Table 3. When this mode is activated, one single joint chroma residual block (resJointC[x][y] in Table 3) is signalled, and residual block for Cb (resCb) and residual block for Cr (resCr) are derived considering information such as tu_cbf_cb, tu_cbf_cr, and CSign, which is a sign value specified in the slice header.
At the encoder side, the joint chroma components are derived as explained in the following. Depending on the mode (listed in the tables above), resJointC{1,2} are generated by the encoder as follows:
resJointC[x][y]=(resCb[x][y]+CSign*resCr[x][y])/2.
resJointC[x][y]=(4*resCb[x][y]+2*CSign*resCr[x][y])/5.
resJointC[x][y]=(4*resCr[x][y]+2*CSign*resCb[x][y])/5.
Different QPs are utilized for the above three modes. For mode 2, the QP offset signalled in PPS for JCCR coded block is applied, while for other two modes, it is not applied, instead, the QP offset signalled in PPS for non-JCCR coded block is applied.
The corresponding specification is as follows:
The variable QpY is derived as follows:
QpY=((qPY_PRED+CuQpDeltaVal+64+2*QpBdOffsetY)%(64+QpBdOffsetY))−QpBdOffsetY (8-933)
The luma quantization parameter Qp′Y is derived as follows:
Qp′Y=QpY+QpBdOffsetY (8-934)
When ChromaArrayType is not equal to 0 and treeType is equal to SINGLE_TREE or DUAL_TREE_CHROMA, the following applies:
qPiChroma=Clip3(−QpBdOffsetC,63,QpY) (8-935)
qPiCb=ChromaQpTable[0][qPiChroma] (8-936)
qPiCr=ChromaQpTable[1][qPiChroma] (8-937)
qPiCbCr=ChromaQpTable[2][qPiChroma] (8-938)
Qp′Cb=Clip3(−QpBdOffsetC,63,qPCb+pps_cb_qp_offset+slice_cb_qp_offset+CuQpOffsetCb)+QpBdOffsetC (8-939)
Qp′Cr=Clip3(−QpBdOffsetC,63,qPCr+pps_cr_qp_offset+slice_cr_qp_offset+CuQpOffsetCr)+QpBdOffsetC (8-940)
Qp′CbCr=Clip3(−QpBdOffsetC,63,qPCbCr+pps_cbcr_qp_offset+slice_cbcr_qp_offset+CuQpOffsetCbCr)+QpBdOffsetC (8-941)
Inputs to this process are:
qP=Qp′Y (8-950)
qP=Max(QpPrimeTsMin,Qp′Y) (8-951)
qP=Qp′CbCr (8-952)
qP=Qp′Cb (8-953)
qP=Qp′Cr (8-954)
where
The QP is derived based on neighboring QPs and the decoded delta QP. The texts related to QP derivation in JVET-P2001-vE is given as follows.
Inputs to this process are:
(xQg−1)>>CtbLog2SizeY is not equal to (xCb)>>CtbLog2SizeY
(yQg)>>CtbLog2SizeY is not equal to (yCb)>>CtbLog2SizeY
(xQg)>>CtbLog2SizeY is not equal to (xCb)>>CtbLog2SizeY
(yQg−1)>>CtbLog2SizeY is not equal to (yCb)>>CtbLog2SizeY
qPY_PRED=(qPY_A+qPY_B+1)>>1 (1115)
The variable QpY is derived as follows:
QpY=((qPY_PRED+CuQpDeltaVal+64+2*QpBdOffset)%(64+QpBdOffset))−QpBdOffset (1116)
The luma quantization parameter Qp′Y is derived as follows:
Qp′Y=QpY+QpBdOffset (1117)
When ChromaArrayType is not equal to 0 and treeType is equal to SINGLE_TREE or DUAL_TREE_CHROMA, the following applies:
qPChroma=Clip3(−QpBdOffset,63,QpY) (1118)
qPCb=ChromaQpTable[0][qPChroma] (1119)
qPCr=ChromaQpTable[1][qPChroma] (1120)
qPCbCr=ChromaQpTable[2]J[qPChroma] (1121)
Qp′Cb=Clip3(−QpBdOffset,63,qPCb+pps_cb_qp_offset+slice_cb_qp_offset+CuQpOffsetCb)+QpBdOffset (1122)
Qp′Cr=Clip3(−QpBdOffset,63,qPCr+pps_cr_qp_offset+slice_cr_qp_offset+CuQpOffsetCr)+QpBdOffset (1123)
Qp′CbCr=Clip3(−QpBdOffset,63,qPCbCr+pps_joint_cbcr_qp_offset+slice_joint_cbcr_qp_offset+CuQpOffsetCbCr)+QpBdOffset (1124)
In the VVC, unless the maximum transform size is smaller than the width or height of one coding unit (CU), one CU leaf node is also used as the unit of transform processing. Therefore, in the proposed implementation, the ACT flag is signalled for one CU to select the color space for coding its residuals. Additionally, following the HEVC ACT design, for inter and IBC CUs, the ACT is only enabled when there is at least one non-zero coefficient in the CU. For intra CUs, the ACT is only enabled when chroma components select the same intra prediction mode of luma component, i.e., direct mode (DM) mode.
The core transforms used for the color space conversions are kept the same as that used for the HEVC. Specifically, the following forward and inverse YCgCo color transform matrices, as described as follows, as applied.
Additionally, to compensate the dynamic range change of residuals signals before and after color transform, the QP adjustments of (−5, −5, −3) are applied to the transform residuals. On the other hand, as shown in
Intra sub-partition prediction (ISP): the ISP sub-partition is only applied to luma while chroma signals are coded without splitting. In the current ISP design, except the last ISP sub-partitions, the other sub-partitions only contain luma component.
The control mechanism is shown in the flowchart 1600 of
where
non_reference_picture_flag
gdr_pic_flag
pic_max_num_merge_cand_minus_max_num_
pic_six_minus_max_num_ibc_merge_cand
pic_joint_cbcr_sign_flag
pic_sao_enabled_present_flag
pic_sao_luma_enabled_flag
pic_sao_chroma_enabled_flag
pic_alf_enabled_present_flag
pic_alf_enabled_flag
pic_num_alf_aps_ids_luma
pic_alf_chroma_idc
pic_alf_aps_id_chroma
pic_cross_component_alf_cb_aps_id
pic_cross_component_cb_filters_signalled_minus1
pic_cross_component_alf_cr_enabled_flag
pic_cross_component_alf_cr_aps_id
pic_cross_component_cr_filters_signalled_minus1
pic_dep_quant_enabled_flag
alf_luma_filter_signal_flag
alf_chroma_filter_signal_flag
alf_cross_component_cb_filter_signal_flag
alf_cross_component_cr_filter_signal_flag
alf_luma_clip_flag
alf_luma_num_filters_signalled_minus1
alf_luma_coeff_delta_idx[filtIdx ]
alf_cross_component_cb_filters_signalled_minus1
alf_cross_component_cr_filters_signalled_minus1
slice_subpic_id
slice_address
num_tiles_in_slice_minus1
slice_type
slice_alf_enabled_flag
slice_num_alf_aps_ids_luma
slice_alf_aps_id_luma[i ]
slice_alf_chroma_idc
slice_alf_aps_id_chroma
slice_cross_component_alf_cb_enabled_flag
slice_cross_component_alf_cb_aps_id
slice_cross_component_cb_filters_signalled_minus1
slice_cross_component_alf_cr_enabled_flag
slice_cross_component_alf_cr_aps_id
slice_cross_component_cr_filters_signalled_minus1
slice_deblocking_filter_override_flag
slice_deblocking_filter_disabled_flag
slice_beta_offset_div2
slice_tc_offset_div2
offset_len_minus1
entry_p0int_offset_minus1 [i ]
slice_header_extension_length
slice_header_extension_data_byte[i ]
pic_cross_component_alf_cb_enabled_flag equal to 1 specifies that cross component Cb filter is enabled for all slices associated with the picture header (PH) and may be applied to Cb colour component in the slices. pic_cross_component_alf_cb_enabled_flag equal to 0 specifies that cross component Cb filter may be disabled for one, or more, or all slices associated with the PH. When not present, pic_cross_component_alf_cb_enabled_flag is inferred to be equal to 0.
pic_cross_component_alf_cb_aps_id specifies the adaptation-parameter_set_id of the ALF APS that the Cb colour component of the slices associated with the PH refers to.
The value of alf_cross_component_cb_filter_signal_flag of the APS Network Abstraction Layer (NAL) unit having aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to pic_cross_component_alf_cb_aps_id may be equal to 1.
pic_cross_component_cb_filters_signalled_minus1 plus 1 specifies the number of cross component Cb filters. The value of pic_cross_component_cb_filters_signalled_minus1 may be in the range 0 to 3
When pic_cross_component_alf_cb_enabled_flag equal to 1, the pic_cross_component_cb_filters_signalled_minus1 may be less than or equal to the value of alf_cross_component_cb_filters_signalled_minus1 in the referenced ALF APS referred to by pic_cross_component_alf_cb_aps_id.
pic_cross_component_alf_cr_enabled_flag equal to 1 specifies that cross component Cr filter is enabled for all slices associated with the PH and may be applied to Cr colour component in the slices. pic_cross_component_alf_cr_enabled_flag equal to 0 specifies that cross component Cr filter may be disabled for one, or more, or all slices associated with the PH. When not present, pic_cross_component_alf_cr_enabled_flag is inferred to be equal to 0.
pic_cross_component_alf_cr_aps_id specifies the adaptation_parameter_set_id of the ALF APS that the Cr colour component of the slices associated with the PH refers to.
The value of alf_cross_component_cr_filter_signal_flag of the APS NAL unit having aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to pic_cross_component_alf_cr_aps_id may be equal to 1.
pic_cross_component_cr_filters_signalled_minus1 plus 1 specifies the number of cross component Cr filters. The value of pic_cross_component_cr_filters_signalled_minus1 may be in the range 0 to 3
When pic_cross_component_alf_cr_enabled_flag equal to 1, the pic_cross_component_cr_filters_signalled_minus1 may be less than or equal to the value of alf_cross_component_cr_filters_signalled_minus1 in the referenced ALF APS referred to by pic_cross_component_alf_cr_aps_id.
alf_cross_component_cb_filter_signal_flag equal to 1 specifies that a cross component Cb filter is signalled. alf_cross_component_cb_filter_signal_flag equal to 0 specifies that a cross component Cb filter is not signalled. When ChromaArrayType is equal to 0, alf_cross_component_cb_filter_signal_flag may be equal to 0.
alf_cross_component_cb_filters_signalled_minus1 plus 1 specifies the number of cross component Cb filters signalled in the current ALF APS. The value of alf_cross_component_cb_filters_signalled_minus1 may be in the range 0 to 3.
alf_cross_component_cb_coeff_plus32[k][j]minus 32 specifies the value of the j-th coefficient of the signalled k-th cross-component Cb filter set. When alf_cross_component_cb_coeff_plus32[k][j] is not present, it is inferred to be equal to 32.
The signalled k-th cross component Cb filter coefficients CcAlfApsCoeffcb[adaptation_parameter_set_id][k] with elements CcAlfApsCoeffcb[adaptation_parameter_set_id][k][j], with j=0 . . . 7 are derived as follows:
CcAlfApsCoeffcb[adaptation_parameter_set_id][k][j]=alf_cross_component_cb_coeff_plus32[k][j]−32 (7-51)
alf_cross_component_cr_filter_signal_flag equal to 1 specifies that a cross component Cr filter is signalled. alf_cross_component_cr_filter_signal_flag equal to 0 specifies that a cross component Cr filter is not signalled. When ChromaArrayType is equal to 0, alf_cross_component_cr_filter_signal_flag may be equal to 0.
alf_cross_component_cr_filters_signalled_minus1 plus 1 specifies the number of cross component Cr filters signalled in the current ALF APS. The value of alf_cross_component_cr_filters_signalled_minus1 may be in the range 0 to 3.
alf_cross_component_cr_coeff_plus32[k][j] minus 32 specifies the value of the j-th coefficient of the signalled k-th cross-component Cr filter set. When alf_cross_component_cr_coeff_abs[k][j] is not present, it is inferred to be equal to 32.
The signalled k-th cross component Cr filter coefficients CcAlfApsCoeffCr[adaptation_parameter_set_id][k] with elements CcAlfApsCoeffCr[adaptation_parameter_set_id][k][j], with j=0 . . . 7 are derived as follows:
CcAlfApsCoeffCr[adaptation_parameter_set_id][k][j]=alf_cross_component_cr_coeff_plus3 2[k][j]−32 (7-52)
Decoder-side Motion Vector Refinement (DMVR) and Bi-directional Optical flow (BIO) do not involve the original signal during refining the motion vectors, which may result in coding blocks with inaccurate motion information. Also, DMVR and BIO sometimes employ the fractional motion vectors after the motion refinements while screen videos usually have integer motion vectors, which makes the current motion information more inaccurate and make the coding performance worse.
7.3.2.3 Sequence Parameter Set RBSP Syntax
sps_bdpcm_chroma_enabled_flag
sps_palette_enabled_flag
sps_act_enabled_flag
The detailed embodiments described below should be considered as examples to explain general concepts. These embodiments should not be interpreted narrowly way. Furthermore, these embodiments can be combined in any manner.
The proposed methods described below may be applied to the deblocking filter. Alternatively, they may be applied to other kinds of in-loop filters, e.g., those rely on quantization parameters.
The methods described below may be also applicable to other decoder motion information derivation technologies in addition to the DMVR and BIO mentioned below.
In the following examples, MVM[i].x and MVM[i].y denote the horizontal and vertical component of the motion vector in reference picture list i (i being 0 or 1) of the block at M (M being P or Q) side. Abs denotes the operation to get the absolute value of an input, and “&&” and “∥” denotes the logical operation AND and OR. Referring to
The embodiments are based on JVET-02001-vE. The newly added texts are shown in underlined bold italicized font. The deleted texts are marked by underlined bold text.
cQpPicOffset=cIdx==1?pps_cb_qp_offset:pps_cr_qp_offset (8-1065)
The variables QpQ and QpP are set equal to the QpY values of the coding units which include the coding blocks containing the sample q0,0 and p0,0, respectively.
The variable QpC is derived as follows:
qPi=Clip3(0,63,((QpQ+QpP+1)>>1)+cQpPicOffset) (8-1132)
QpC=ChromaQpTable[cIdx−1][qPi] (8-1133)
qPi=(QpQ+QpP+1)>>1 (8-1132)
QpC=ChromaQpTable[cIdx−1][qPi]+cQpPicOffset (8-1133
NOTE—The variable cQpPicOffset provides an adjustment for the value of pps_cb_qp_offset or pps_cr_qp_offset, according to whether the filtered chroma component is the Cb or Cr component. However, to avoid the need to vary the amount of the adjustment within the picture, the filtering process does not include an adjustment for the value of slice_cb_qp_offset or slice_cr_qp_offset nor (when cu_chroma_qp_offset_enabled_flag is equal to 1) for the value of CuQpOffsetCb, CuQpOffsetCr, or CuQpOffsetCbCr.
The value of the variable β′ is determined as specified in Table 8-18 based on the quantization parameter Q derived as follows:
Q=Clip3(0,63,QpC+(slice_beta_offset_div2<<1)) (8-1134)
where slice_beta_offset_div2 is the value of the syntax element slice_beta_offset_div2 for the slice that contains sample q0,0.
The variable β is derived as follows:
β=β′*(1<<(BitDepthC−8)) (8-1135)
The value of the variable tC′ is determined as specified in Table 8-18 based on the chroma quantization parameter Q derived as follows:
Q=Clip3(0,65,QpC+2*(bS−1)+(slice_tc_offset_div2<<1)) (8-1136)
where slice_tc_offset_div2 is the value of the syntax element slice_tc_offset_div2 for the slice that contains sample q0,0.
The variable tC is derived as follows:
t
C=(BitDepthC<10)?(tC′+2)>>(10−BitDepthC): tC′*(1<<(BitDepthC−8)) (8-1137)
Inputs to this process are:
8.8.3.6 Derivation Process of Boundary Filtering Strength Inputs to this process are:
a picture sample array recPicture,
Inputs to this process are:
dp0L=(dP0+Abs(p5,0−2*p4,0+p3,0)+1)>>1 (8-1087)
dp3L=(dp3+Abs(p5,3−2*p4,3+p3,3)+1)>>1 (8-1088)
dp0L=dp0 (8-1089)
dp3L=dp3 (8-1090)
maxFilterLengthP=3 (8-1091)
maxFilterLengthP=sidePisLarigeBlk?maxFilterLenkthP:3
dq0L=(dq0+Abs(q5,0−2*q4,0+q3,0)+1)>>1 (8-1092)
dq3L=(dq3+Abs(q5,3−2*q4,3+q3,3)+1)>>1 (8-1093)
dq0L=dq0 (8-1094)
dq3L=dq3 (8-1095)
maxFilterLengthQ=sidePisLarmeBlk?maxFilterLengthQ: 3
This process is only invoked when ChromaArrayType is not equal to 0.
Inputs to this process are:
maxK=(SubHeightC==1)?3:1 (8-1124)
maxK=(SubWidthC==1)?3:1 (8-1125)
The values pi and qi with i=0 . . . maxFilterLengthCbCr and k=0 . . . maxK are derived as follows:
q
i,k=recPicture[xCb+xBl+i][yCb+yBl+k] (8-1126)
p
i,k=recPicture[xCb+xBl−i−1][yCb+yBl+k] (8-1127)
subSampleC=SubHeightC (8-1128)
q
i,k=recPicture[xCb+xBl+k][yCb+yBl+i] (8-1129)
p
i,k=recPicture[xCb+xBl+k][yCb+yBl−i−1 ] (8-1130)
subSampleC=SubWidthC (8-1131)
When ChromaArrayType is not equal to 0 and treeType is equal to SINGLE TREE or DUAL TREE CHROMA, the following applies:
qPiChroma=Clip3(−QpBdOffsetC,63,QpY) (8-935)
qPiCb=ChromaQpTable[0][qPichroma] (8-936)
qPiCr=ChromaQpTable[1][qPiChroma] (8-937)
qPiCbCr=ChromaQpTable[2][qPiChroma] (8-938)
Qp′Cb=Clip3(−QpBdOffsetC,63,qPCb+pps_cb_qp_offset+slice_cb_qp_offset+CuQp OffsetCb) (8-939)
Qp′Cr=Clip3(−QpBdOffsetC,63,qPCr+pps_cr_pp_offset+slice_cr_pp_offset+CuQpOffsetCr) (8-940)
Qp′CbCr=Clip3(−QpBdOffsetC,63,qPCbCr+pps_cbcr_pp_offset+slice_cbcr_pp_offset+CuQpOffsetCbCr) (8-941)
The variables QpQ and QpP are set equal to the corresponding Qp′Cb or Qp′Cr or Qp′CbCr values of the coding units which include the coding blocks containing the sample q0,0 and p0,0, respectively.
The variable QpC is derived as follows:
QpC=(QpQ+QpP+1)>>1 (8-1133)
The value of the variable β′ is determined as specified in Table 8-18 based on the quantization parameter Q derived as follows:
Q=Clip3(0,63,QpC+(slice_beta_offset_div2<<1)) (8-1134)
where slice_beta_offset_div2 is the value of the syntax element slice_beta_offset_div2 for the slice that contains sample q0,0.
The variable β is derived as follows:
β=β′*(1<<(BitDepthC−8)) (8-1135)
The value of the variable tC′ is determined as specified in Table 8-18 based on the chroma quantization parameter Q derived as follows:
Q=Clip3(0,65,QpC+2*(bS−1)+(slice_tc_offset_div2<<1)) (8-1136)
where slice_tc_offset_div2 is the value of the syntax element slice_tc_offset_div2 for the slice that contains sample q0,0.
The variable tC is derived as follows:
t
C=(BitDepthC<10)?(tC′+2)>>(10−BitDepthC): tC′*(1<<(BitDepthC−8)) (8-1137)
When maxFilterLengthCbCr is equal to 1 and bS is not equal to 2, maxFilterLengthCbCr is set equal to 0.
This process is only invoked when ChromaArrayType is not equal to 0.
Inputs to this process are:
maxK=(SubHeightC==1)?3:1 (8-1124)
maxK=(SubWidthC==1)?3:1 (8-1125)
The values pi and qi with i=0 . . . maxFilterLengthCbCr and k=0 . . . maxK are derived as follows:
q
i,k=recPicture[xCb+xBl+i][yCb+yBl+k] (8-1126)
p
i,k=recPicture[xCb+xBl−i−1][yCb+yBl+k] (8-1127)
subSampleC=SubHeightC (8-1128)
q
i,k=recPicture[xCb+xBl+k][yCb+yBl+i] (8-1129)
p
i,k=recPicture[xCb+xBl+k][yCb+yBl−i−1 ] (8-1130)
subSampleC=SubWidthC (8-1131)
The variables QpQ and QpP are set equal to the QpY values of the coding units which include the coding blocks containing the sample q0,0 and p0,0, respectively.
The variables jccr_flagP and jccr_flagQ are set equal to the tu_joint_cbcr_residual_flag values of the coding units which include the coding blocks containing the sample q0,0 and p0,0, respectively.
The variable QpC is derived as follows:
qPi=Clip3(0,63,((QpQ+QpP+1)>>1)+cQpPicOffset) (8-1132)
qPi=Clip3(0,63,((QpQ+(jccr_flagP?pps_joint_cbcr_qp_offset: cQpPicOffset)+QpP+(jccr_flag?pps_joint_cbcr_qp_offset: cQpPicOffset)+1)>>1))
QpC=ChromaQpTable[cIdx−1][qPi] (8-1133)
This process is only invoked when ChromaArrayType is not equal to 0.
Inputs to this process are:
maxK=(SubHeightC==1)?3:1 (8-1124)
maxK=(SubWidthC==1)?3:1 (8-1125)
The values pi and qi with i=0 . . . maxFilterLengthCbCr and k=0 . . . maxK are derived as follows:
q
i,k=recPicture[xCb+xBl+i][yCb+yBl+k] (8-1126)
p
i,k=recPicture[xCb+xBl−i−1][yCb+yBl+k] (8-1127)
subSampleC=SubHeightC (8-1128)
q
i,k=recPicture[xCb+xBl+k][yCb+yBl+i] (8-1129)
p
i,k=recPicture[xCb+xBl+k][yCb+yBl−i−1 ] (8-1130)
subSampleC=SubWidthC (8-1131)
The variables QpQ and QpP are set equal to the QpY values of the coding units which include the coding blocks containing the sample q0,0 and p0,0, respectively.
The variables QpQ is set equal to the luma quantization parameter QpY of the luma coding unit that covers the luma location (xCb+cbWidth/2, yCb+cbHeight/2) wherein cbWidth specifies the width of the current chroma coding block in luma samples, and cbHeight specifies the height of the current chroma coding block in luma samples.
The variables QpP is set equal to the luma quantization parameter QpY of the luma coding unit that covers the luma location (xCb′+cbWidth′/2, yCb′+cbHeight′/2) wherein (xCb′, yCb′) the top-left sample of the chroma coding block covering q0,0 relative to the top-left chroma sample of the current picture, cbWidth′ specifies the width of the current chroma coding block in luma samples, and cbHeight specifies the height of the current chroma coding block in luma samples.
The variable QpC is derived as follows:
qPi=Clip3(0,63,((QpQ+QpP+1)>>1)+cQpPicOffset) (8-1132)
QpC=ChromaQpTable[cIdx−1][qPi] (8-1133)
Q=Clip3(0,63,QpC+(slice_beta_offset_div2<<1)) (8-1134)
where slice_beta_offset_div2 is the value of the syntax element slice_beta_offset_div2 for the slice that contains sample q0,0.
The variable β is derived as follows:
β=β′*(1<<(BitDepthC−8)) (8-1135)
The value of the variable tC′ is determined as specified in Table 8-18 based on the chroma quantization parameter Q derived as follows:
Q=Clip3(0,65,QpC+2*(bS−1)+(slice_tc_offset_div2<<1)) (8-1136)
where slice_tc_offset_div2 is the value of the syntax element slice_tc_offset_div2 for the slice that contains sample q0,0.
When making filter decisions for the depicted three samples (with solid circles), the QPs of the luma CU that covers the center position of the chroma CU including the three samples is selected. Therefore, for the 1st, 2nd and 3rd chroma sample (depicted in
In this way, how to select luma CU for chroma quantization/dequantization process is aligned with that for chroma filter decision process.
Inputs to this process are:
qP=Qp′Y (8-950)
qP=Max(QpPrimeTsMin,Qp′Y) (8-951)
qP=Qp′CbCr (8-952)
qP=Qp′Cb (8-953)
qP=Qp′Cr (8-954)
Inputs to this process are:
firstCompIdx=(treeType==DUAL_TREE_CHROMA)?1:0 (8-1022)
lastCompIdx=(treeType==DUAL_TREE_LUMA∥ChromaArrayType==0)?0:2 (8-1023)
For each coding unit and each coding block per colour component of a coding unit indicated by the colour component index cIdx ranging from firstCompIdx to lastCompIdx, inclusive, with coding block width nCbW, coding block height nCbH and location of top-left sample of the coding block (xCb, yCb), when cIdx is equal to 0, or when cIdx is not equal to 0 and edgeType is equal to EDGE_VER and xCb % 8 is equal 0, or when cIdx is not equal to 0 and edgeType is equal to EDGE_HOR and yCb % 8 is equal to 0, the edges are filtered by the following ordered steps:
. . .
5. The picture sample array recPicture is derived as follows:
Inputs to this process are:
Inputs to this process are:
cQpPicOffset=cIdx==1?pps_cb_qp_offset:pps_cr_pp_offset (8-1065)
cQpPicOffset=(pps_cb_qp_offset+pps_cr_pp_offset+1)>>1 (8-1065)
This process is only invoked when ChromaArrayType is not equal to 0.
Inputs to this process are:
maxK=(SubHeightC==1)?3:1 (8-1124)
maxK=(SubWidthC==1)?3:1 (8-1125)
The values pi and qi with c=0 . . . 1, i=0 . . . maxFilterLengthCbCr and k=0 . . . maxK are derived as follows:
qc,i,k=recPicture[c][xCb+xBl+i][yCb+yBl+k] (8-1126)
pc,i,k=recPicture[c][xCb+xBl−i−1][yCb+yBl+k] (8-1127)
subSampleC=SubHeightC (8-1128)
qc,i,k=recPicture[c][xCb+xBl+k][yCb+yBl+i] (8-1129)
pc,i,k=recPicture[c][xCb+xBl+k][yCb+yBl−i−1 ] (8-1130)
subSampleC=SubWidthC (8-1131)
The variables QpQ and QpP are set equal to the QpY values of the coding units which include the coding blocks containing the sample q0,0 and p0,0, respectively.
The variable QpC is derived as follows:
qPi=Clip3(0,63,((QpQ+QpP+1)>>1)+cQpPicOffset) (8-1132)
QpC=ChromaQpTable[cIdx−1][qPi]+cQpPicOffset (8-1133)
QpC=((ChromaQpTable[0][qPi]+ChromaQpTable[1][qPi]+1)>>1)+cQpPicOffset (8-1133)
Q=Clip3(0,63,QpC+(slice_beta_offset_div2<<1)) (8-1134)
where slice_beta_offset_div2 is the value of the syntax element slice_beta_offset_div2 for the slice that contains sample q0,0.
The variable β is derived as follows:
β=β′*(1<<(BitDepthC−8)) (8-1135)
The value of the variable tC′ is determined as specified in Table 8-18 based on the chroma quantization parameter Q derived as follows:
Q=Clip3(0,65,QpC+2*(bS−1)+(slice_tc_offset_div2<<1)) (8-1136)
where slice_tc_offset_div2 is the value of the syntax element slice_tc_offset_div2 for the slice that contains sample q0,0.
The variable tC is derived as follows:
t
C=(BitDepthC<10)?(tC′+2)>>(10−BitDepthC): tC′*(1<<(BitDepthC−8)) (8-1137)
When maxFilterLengthCbCr is equal to 1 and bS is not equal to 2, maxFilterLengthCbCr is set equal to 0.
When maxFilterLengthCbCr is equal to 3, the following ordered steps apply:
n1=(subSampleC==2)?1:3 (8-1138)
dp0c=Abs(pc,2,0−2*pc,1,0+pc,0,0) (8-1139)
dp1c=Abs(pc,2,n1−2*pc,1,n1+pc,0,n1) (8-1140)
dq0c=Abs(qc,2,0−2*qc,1,0+qc,0,0) (8-1141)
dq1c=Abs(qc,2,n1−2*qc,1,n1+qc,0,n1) (8-1142)
dpq0c=dp0c+dq0g (8-1143)
dpq1c=dp1c+dq1c (8-1144)
dpc=dp0c+dp1c (8-1145)
dqc=dq0c+dq1c (8-1146)
dc=dpq0c+dpq1c (8-1147)
This process is only invoked when ChromaArrayType is not equal to 0.
Inputs to this process are:
q
i,k=recPicture[cIdx][xCb+xBl+i][yCb+yBl+k] (8-1150)
p
i,k=recPicture[cIdx][xCb+xBl−i−1][yCb+yBl+k] (8-1151)
q
i,k=recPicture[cIdx][xCb+xBl+k][yCb+yBl+i] (8-1152)
p
i,k=recPicture[cIdx][xCb+xBl+k][yCb+yBl−i−1 ] (8-1153)
Depending on the value of edgeType, the following applies:
recPicture[cIdx][xCb+xBl+i][yCb+yBl+k]=qi′ (8-1154)
recPicture[cIdx][xCb+xBl−i−1][yCb+yBl+k]=pi′ (8-1155)
recPicture[cIdx][xCb+xBl+k][yCb+yBl+i]=qi′
recPicture[cIdx][xCb+xBl+k][yCb+yBl−i−1]=pi′ (8-1156)
. . .
The variables QpQ and QpP are set equal to the QpY values of the coding units which include the coding blocks containing the sample q0,0 and p0,0, respectively.
The variable QpC is derived as follows:
qPi=Clip3(0,63,((QpQ+QpP+1)>>1)+cQpPicOffset) (8-1132)
QpC=ChromaQpTable[cIdx−1][qPi] (8-1133)
When ChromaArrayType is not equal to 0 and treeType is equal to SINGLE TREE or DUAL TREE CHROMA, the following applies:
qPiChroma=Clip3(−QpBdOffsetC,63,QpY) (8-935)
pPiCb=ChromaQpTable[0][qPiChroma] (8-936)
qPiCr=ChromaQpTable[1][qPiChroma] (8-937)
qPiCbCr=ChromaQpTable[2][qPiChroma] (8-938)
Qp′Cb=Clip3(−QpBdOffsetC,63,qPCb+pps_cb_qp_offset+slice_cb_qp_offset+Cu QpOffsetCb)+QpBdOffsetC (8-939)
Qp′Cr=Clip3(−QpBdOffsetC,63,qPCr+pps_cr_qp_offset+slice_cr_qp_offset+CuQp OffsetCr)+QpBdOffsetC (8-940)
Qp′CbCr=Clip3(−QpBdOffsetC,63,qPCbCr+pps_cbcr_pp_offset+slice_cbcr_qp_offset+CuQpOffsetCbCr)+QpBdOffsetC (8-941)
The variables QpO and QpP are set equal to the Qp′Cb value when cIdx is equal to 1, or the Qp′Cr value when cIdx is equal to 2, or Qp′CbCr when tu_joint_cbcr_residual_flag is equal to 1, of the coding units which include the coding blocks containing the sample q0,0 and p0,0, respectively.
The variable QpC is derived as follows:
QpC=(QpQ+QpP+1)>>1
. . .
The variables QpQ and QpP are set equal to the QpY values of the coding units which include the coding blocks containing the sample q0,0 and p0,0, respectively.
The variable QpC is derived as follows:
qPi=Clip3(0,63,((QpQ+QpP+1)>>1)+cQpPicOffset) (8-1132)
QpC=ChromaOpTable[cIdx−1][qPi] (8-1133)
QpC=(QpQ+QpP+1)>>1
. . .
The embodiments are based on JVET-P2001-vE. The newly added texts are highlight by underlined bold italicized text. The deleted texts are marked by underlined Bold Text.
This process is only invoked when ChromaArrayType is not equal to 0.
Inputs to this process are:
QpC=(QpQ−QpBdOffset+QpP−QpBdOffset+1)>>1 (1321)
The embodiments are based on JVET-P2001-vE. The newly added texts are highlight by indicated as bold, underlined, and italicized text. The deleted texts are marked by underlined bold text.
This process is only invoked when ChromaArrayType is not equal to 0.
Inputs to this process are:
QpC=(QpQ−QpBdOffset+QpP−QpBdOffset+1)>>1 (1321)
. . .
if( deblocking_filter_override_enabled_flag ) {
pic_deblocking_filter_override_present_flag
u(1)
if( pic_deblocking_filter_override_present_flag ) {
pic_deblocking_filter_override_flag
u(1)
if( pic_deblocking_filter_override_flag )
{
pic_deblocking_filter_disabled_flag
u(1)
if( !pic_deblocking_filter_disabled_flag ) {
pic_beta_offset_div2
se(v)
pic_tc_offset_div2
se(v)
}
}
}
}
!pic_deblocking_filter_override_present_flag
)
pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 specify the default deblocking parameter offsets for β and tC (divided by 2) that are applied to Cb component for slices referring to the PPS, unless the default deblocking parameter offsets are overridden by the deblocking parameter offsets present in the slice headers of the slices referring to the PPS. The values of pps_beta_offset_div2 and pps_tc-offset_div2 may both be in the range of −6 to 6, inclusive. When not present, the value of pps_beta_offset_div2 and pps_tc_offset_div2 are inferred to be equal to 0.
pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 specify the default deblocking parameter offsets for β and tC (divided by 2) that are applied to Cr component for slices referring to the PPS, unless the default deblocking parameter offsets are overridden by the deblocking parameter offsets present in the slice headers of the slices referring to the PPS. The values of pps_beta_offset_div2 and pps_tc_offset_div2 may both be in the range of −6 to 6, inclusive. When not present, the value of pps_beta_offset_div2 and pps_tc_offset_div2 are inferred to be equal to 0.
pic_cb_beta_offset_div2 and pic_cb_tc_offset_div2 specify the deblocking parameter offsets for β and tC (divided by 2) that are applied to Cb component for the slices associated with the PH. The values of pic_beta_offset_div2 and pic_tc_offset_div2 may both be in the range of −6 to 6, inclusive. When not present, the values of pic_beta_offset_div2 and pic_tc_offset_div2 are inferred to be equal to pps_beta_offset_div2 and pps_tc_offset_div2, respectively.
pic_cr_beta_offset_div2 and pic_cr_tc_offset_div2 specify the deblocking parameter offsets for β and tC (divided by 2) that are applied to Cr component for the slices associated with the PH. The values of pic_beta_offset_div2 and pic_tc_offset_div2 may both be in the range of −6 to 6, inclusive. When not present, the values of pic_beta_offset_div2 and pic_tc_offset_div2 are inferred to be equal to pps_beta_offset_div2 and pps_tc_offset_div2, respectively.
slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify the deblocking parameter offsets for β and tC (divided by 2) that are applied to Cb component for the current slice. The values of slice_beta_offset_div2 and slice_tc_offset_div2 may both be in the range of −6 to 6, inclusive. When not present, the values of slice_beta_offset_div2 and slice_tc_offset_div2 are inferred to be equal to pic_beta_offset_div2 and pic_tc_offset_div2, respectively.
slice_cr_beta_offset_div2 and slice_cr_tc_offset_div2 specify the deblocking parameter offsets for β and tC (divided by 2) that are applied to Cb component for the current slice. The values of slice_beta_offset_div2 and slice_tc_offset_div2 may both be in the range of −6 to 6, inclusive. When not present, the values of slice_beta_offset_div2 and slice_tc_offset_div2 are inferred to be equal to pic_beta_offset_div2 and pic_tc_offset_div2, respectively.
. . .
The value of the variable β′ is determined as specified in Table 41 based on the quantization parameter Q derived as follows:
Q=Clip3(0,63,QpC+(slice_beta_offset_div2<<1)) (1322)
Q=Clip3(0,63,QpC+(slice_cb_beta_offset_div2<<1))
Q=Clip3(0,63,QpC+(slice_cr_beta_offset_div2<<1))
where slice_beta_offset_div2 is the value of the syntax element slice_beta_offset_div2 for the slice that contains sample q0,0.
The variable β is derived as follows:
β=β′*(1<<(BitDepth−8)) (1323)
The value of the variable tC′ is determined as specified in Table 41 based on the chroma quantization parameter Q derived as follows:
Q=Clip3(0,65,QpC+2*(bS−1)+(slice_tc_offset_div2<<1)) (1324)
Q=Clip3(0,65,QpC+2*(bS−1)+(slice_cb_tc_offset_div2<<1))
Q=Clip3(0,65,QpC+2*(bS−1)+(slice_cr_tc_offset_div2<<1))
This embodiment is on top of embodiment #15.
pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 specify the default deblocking parameter offsets for β and tC (divided by 2) that are applied to Cb component for slices referring to the PPS, unless the default deblocking parameter offsets are overridden by the deblocking parameter offsets present in the slice headers of the slices referring to the PPS. The values of pps_beta_offset_div2 and pps_tc_offset_div2 may both be in the range of −6 to 6, inclusive. When not present, the value of pps_beta_offset_div2 and pps_tc_offset_div2 are inferred to be equal to 0.
pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 specify the default deblocking parameter offsets for β and tC (divided by 2) that are applied to Cr component for slices referring to the PPS, unless the default deblocking parameter offsets are overridden by the deblocking parameter offsets present in the slice headers of the slices referring to the PPS. The values of pps_beta_offset_div2 and pps_tc_offset_div2 may both be in the range of −6 to 6, inclusive. When not present, the value of pps_beta_offset_div2 and pps_tc_offset_div2 are inferred to be equal to 0.
slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify the deblocking parameter offsets for β and tC (divided by 2) that are applied to Cb component for the current slice. The values of slice_beta_offset_div2 and slice_tc_offset_div2 may both be in the range of −6 to 6, inclusive. When not present, the values of slice_beta_offset_div2 and slice_tc_offset_div2 are inferred to be equal to pps_beta_offset_div2 and pps_tc_offset_div2, respectively.
slice_cr_beta_offset_div2 and slice_cr_tc_offset_div2 specify the deblocking parameter offsets for β and tC (divided by 2) that are applied to Cb component for the current slice. The values of slice_beta_offset_div2 and slice_tc_offset_div2 may both be in the range of −6 to 6, inclusive. When not present, the values of slice_beta_offset_div2 and slice_tc_offset_div2 are inferred to be equal to pps_beta_offset_div2 and pps_tc_offset_div2, respectively.
. . .
The value of the variable β′ is determined as specified in Table 41 based on the quantization parameter Q derived as follows:
Q=Clip3(0,63,QpC+(slice_beta_offset_div2<<1)) (1322)
Q=Clip3(0,63,QpC+(slice_cb_beta_offset_div2<<1))
Q=Clip3(0,63,QpC+(slice_cr_beta_offset_div2<<1))
where slice_beta_offset_div2 is the value of the syntax element slice_beta_offset_div2 for the slice that contains sample q0,0.
The variable β is derived as follows:
β=β′*(1<<(BitDepth−8)) (1323)
The value of the variable tC′ is determined as specified in Table 41 based on the chroma quantization parameter Q derived as follows:
Q=Clip3(0,65,QpC+2*(bS−1)+(slice_tc_offset_div2<<1)) (1324)
Q=Clip3(0,65,QpC+2*(bS−1)+(slice_cb_tc_offset_div2<<1))
Q=Clip3(0,65,QpC+2*(bS−1)+(slice_cr_tc_offset_div2<<1))
. . .
This embodiment is based on embodiment #17.
pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 specify the default deblocking parameter offsets for β and tC (divided by 2) that are applied to Cb component for the current PPS. The values of pps_beta_offset_div2 and pps_tc_offset_div2 may both be in the range of −6 to 6, inclusive. When not present, the value of pps_beta_offset_div2 and pps_tc_offset_div2 are inferred to be equal to 0.
pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 specify the default deblocking parameter offsets for β and tC (divided by 2) that are applied to Cr component for the current PPS. The values of pps_beta_offset_div2 and pps_tc_offset_div2 may both be in the range of −6 to 6, inclusive. When not present, the value of pps_beta_offset_div2 and pps_tc_offset_div2 are inferred to be equal to 0.
slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify the deblocking parameter offsets for β and tC (divided by 2) that are applied to Cb component for the current slice. The values of slice_beta_offset_div2 and slice_tc_offset_div2 may both be in the range of −6 to 6, inclusive.
slice_cr_beta_offset_div2 and slice_cr_tc_offset_div2 specify the deblocking parameter offsets for β and tC (divided by 2) that are applied to Cb component for the current slice. The values of slice_beta_offset_div2 and slice_tc_offset_div2 may both be in the range of −6 to 6, inclusive.
. . .
The value of the variable β′ is determined as specified in Table 41 based on the quantization parameter Q derived as follows:
Q=Clip3(0,63,qP+(slice_beta_offset_div2<<1)) (1262)
Q=Clip3(0,63,qP+((pps_beta_offset_div2+slice_beta_offset_div2)<<1)) (1262)
where slice_beta_offset_div2 is the value of the syntax element slice_beta_offset_div2 for the slice that contains sample q0,0.
The variable β is derived as follows:
β=β′*(1<<(BitDepth−8)) (1263)
The value of the variable tC′ is determined as specified in Table 41 based on the quantization parameter Q derived as follows:
Q=Clip3(0,65,qP+2*(bS−1)+(slice_tc_offset_div2<<1)) (1264)
Q=Clip3(0,65,qP+2*(bS−1)+((pps_tc_offset_div2+slice_tc_offset_div2)<<1)) (1264)
. . .
The value of the variable β′ is determined as specified in Table 41 based on the quantization parameter Q derived as follows:
Q=Clip3(0,63,QpC+(slice_beta_offset_div2<<1)) (1322)
Q=Clip3(0,63,QpC+((pps_cb_beta_offset_div2+slice_cb_beta_offset_div2)<<1))
Q=Clip3(0,63,QpC+((pps_cr_beta_offset_div2+slice_cr_beta_offset_div2)<<1))
where slice_beta_offset_div2 is the value of the syntax element slice_beta_offset_div2 for the slice that contains sample q0,0.
The variable β is derived as follows:
β=β′*(1<<(BitDepth−8)) (1323)
The value of the variable tC′ is determined as specified in Table 41 based on the chroma quantization parameter Q derived as follows:
Q=Clip3(0,65,QpC+2*(bS−1)+(slice_tc_offset_div2<<1)) (1324)
Q=Clip3(0,65,QpC+2*(bS−1)+((pps_cb_tc_offset_div2+slice_cb_tc_offset_div2)<<1))
Q=Clip3(0,65,QpC+2*(bS−1)+((pps_cr_tc_offset_div2+slice_cr_tc_offset_div2)<<1))
This embodiment is related to the ACT.
intra_bdpcm_chroma_flag equal to 1 specifies that BDPCM is applied to the current chroma coding blocks at the location (x0, y0), i.e. the transform is skipped, the intra chroma prediction mode is specified by intra_bdpcm_chroma_dir_flag. intra_bdpcm_chroma_flag equal to 0 specifies that BDPCM is not applied to the current chroma coding blocks at the location (x0, y0).
When intra_bdpcm_chroma_flag is not present it is inferred to be equal to 0. it is inferred to be equal to sps_bdpcm_chroma_enabled_flag && cu_act_enabled_flag && intra_bdpcm_luma_flag.
The variable BdpcmFlag[x][y][cIdx] is set equal to intra_bdpcm_chroma_flag for x=x0 . . . x0+cbWidth−1, y=y0 . . . y0+cbHeight−1 and cIdx=1 . . . 2.
intra_bdpcm_chroma_dir_flag equal to 0 specifies that the BDPCM prediction direction is horizontal. intra_bdpcm_chroma_dir_flag equal to 1 specifies that the BDPCM prediction direction is vertical.
When intra_bdpcm_chroma_dir_flag is not present, it is inferred to be equal to (cu_act_enabled_flag?intra_bdpcm_luma_dir_flag: 0).
The variable BdpcmDir[x][y][cIdx] is set equal to intra_bdpcm_chroma_dir_flag for x=x0 . . . x0+cbWidth−1, y=y0 . . . y0+cbHeight−1 and cIdx=1 . . . 2.
This embodiment is related to the QP derivation for deblocking.
Inputs to this process are:
QpQ=Max(QpPrimeTsMin,QpQ+QpBdOffset)−QpBdOffset
QpP is set to the QpY value of the coding units which include the coding blocks containing the sample p0,0.
If the transform skip flag of the coding blocks containing the sample p0,0 is equal to 1,
QpP=Max(QpPrimeTsMin,QpP+QpBdOffset)−QpBdOffset
This process is only invoked when ChromaArrayType is not equal to 0.
Inputs to this process are:
QpP=Max(transform_skip_flag[xTbP][yTbP][cIdx]?QpPrimeTsMin:0,QpP)
The variable QpQ is derived as follows:
QpQ=Max(transform_skip_flag[xTbQ][yTb][cIdx]?QpPrimeTsMin:0,QpQ)
QpC=(QpQ−QpBdOffset+QpP−QpBdOffset+1)>>1 (1321)
This embodiment is related to the QP derivation for deblocking.
Inputs to this process are:
QpQ=Max(QpPrimeTsMin,QpQ+QpBdOffset)−QpBdOffset
If the transform_skip_flag of the coding unit containing the sample p0,0 is equal to 1, QpP is modified to be:
QpP=Max(QpPrimeTsMin,QpP+QpBdOffset)−QpBdOffset
. . .
This process is only invoked when ChromaArrayType is not equal to 0.
Inputs to this process are:
QpP=Max(QpPrimeTsMin,QpP)
The variable QpQ is derived as follows:
QpQ=Max(QpPrimeTsMin,QpQ)
QpC=(QpQ−QpBdOffset+QpP−QpBdOffset+1)>>1 (1321)
This embodiment is related to CC-ALF. The newly added texts on top of the draft provided by JVET-Q0058 are highlight by underlined bold italicized text. In this embodiment, the signaling of CC-ALF related information are under the condition check of ChromaArraryType.
Alternatively, the newly added “ChromaArrayType !=0” may be replaced by “chroma_format_idc! 0”
This embodiment is related to CC-ALF. The newly added texts on top of the draft provided by JVET-Q0058 are highlight by underlined bold italicized text.
sps_ccalf_enabled_flag
semantics
sps_ccalf_enabled_flag equal to 0 specifies that the cross component adaptive loop filter is disabled. sps_ccalf_enabled_flag equal to 1 specifies that the cross component adaptive loop filter is enabled.
Alternatively, the following may apply:
if (sps alf enabled flag)
sps ccalf enabled flag
u(1)
Alternatively, the following may apply:
if (sps_alf_enabled_flag && chroma_format_idc != 0)
sps ccalf enabled flag
u(1)
Alternatively, the following may apply:
if (sps alf enabled flag && ChromaArrayType != 0)
sps ccalf enabled flag
u(1)
semantics
sps_ccalf_enabled_flag equal to 0 specifies that the cross component adaptive loop filter is disabled. sps_ccalf_enabled_flag equal to 1 specifies that the cross component adaptive loop filter is enabled. When not present, it is inferred to be 0.
no ccalf constraint flag
no_ccalf_constraint_flag equal to 1 specifies that sps_ccalf_enabled_flag may be equal to 0. no_ccalf_constraint_flag equal to 0 does not impose such a constraint.
}
if( sps ccalf enabled flag && ChromaArray Type != 0) {
pic ccalf enabled present flag
u(1)
if( pic_ccalf_enabled_present_flag ) {
Alternatively, the following apply:
}
if( sps_ccalf_enabled_flag) {
pic ccalf enabled present flag
u(1)
if( pic ccalf enabled present flag ) {
Alternatively, the following apply:
}
pic ccalf enabled present flag
u(1)
if( pic_ccalf_enabled_present_flag ) {
pic_ccalf_enabled_present_flag equal to 1 specifies that pic_ccalf_enabled_flag, pic_cross_component_alf_cb_enabled_flag, pic_cross_component_alf_cb_aps_id, pic_cross_component_cb_filters_signalled_minus1,
pic_cross_component_alf_cr_enabled_flag, pic_cross_component_alf_cr_aps_id, and pic_cross_component_cr_filters_signalled_minus1 are present in the PH.
pic_alf_enabled_present_flag equal to 0 specifies that pic_cross_component_alf_cb_enabled_flag, pic_cross_component_alf_cb_aps_id, pic_cross_component_cb_filters_signalled_minus1,
pic_cross_component_alf_cr_enabled_flag, pic_cross_component_alf_cr_aps_id, and pic_cross_component_cr_filters_signalled_minus1 are not present in the PH. When pic_alf_enabled_present_flag is not present, it is inferred to be equal to 0.
This embodiment is related to high level syntax and is based on JVET-P2001-vE. The newly added texts are highlight by underlined bold italicized text. The deleted texts are marked by underlined bold text.
chroma
_format_idc
ChromaArrayType
= = 3 )
This embodiment is related to high level syntax and is based on JVET-P2001-vE. The newly added texts are highlight by underlined bold italicized text. The deleted texts are marked by underlined bold text.
sps_bdpcm_chroma_enabled_flag equal to 1 specifies that intra_bdpcm_chroma_flag may be present in the coding unit syntax for intra coding units. sps_bdpcm_chroma_enabled_flag equal to 0 specifies that intra_bdpcm_chroma_fag is not present in the coding unit syntax for intra coding units. When not present, the value of sps_bdpcm_chroma_enabled_flag is inferred to be equal to 0.
When ChromaArrayType is not equal to 3, sps_bdpcm_chroma_enabled_flag may be equal to 0. sps_palette_enabled_flag equal to 1 specifies that pred_mode_plt_flag may be present in the coding unit syntax. sps_palette_enabled_flag equal to 0 specifies that pred_mode_plt_flag is not present in the coding unit syntax. When sps_palette_enabled_flag is not present, it is inferred to be equal to 0.
When ChromaArrayType is not equal to 3, sps_palette_enabled_flag may be equal to 0. sps_act_enabled_flag equal to 1 specifies that adaptive colour transform may be used and the cu_act_enabled_flag may be present in the coding unit syntax. sps_act_enabled_flag equal to 0 specifies that adaptive colour transform is not used and cu_act_enabled_flag is not present in the coding unit syntax. When sps_act_enabled_flag is not present, it is inferred to be equal to 0.
When ChromaArrayType is not equal to 3, sps_act_enabled_flag may be equal to 0.
In the present document, the term “video processing” may refer to video encoding, video decoding, video compression or video decompression. For example, video compression algorithms may be applied during conversion from pixel representation of a video to a corresponding bitstream or vice versa. The bitstream representation of a current video block may, for example, correspond to bits that are either co-located or spread in different places within the bitstream, as is defined by the syntax. For example, a macroblock may be encoded in terms of transformed and coded error residual values and also using bits in headers and other fields in the bitstream.
It will be appreciated that the disclosed methods and techniques will benefit video encoder and/or decoder embodiments incorporated within video processing devices such as smartphones, laptops, desktops, and similar devices by allowing the use of the techniques disclosed in the present document.
As shown in
Source device 110 may include a video source 112, a video encoder 114, and an input/output (I/O) interface 116.
Video source 112 may include a source such as a video capture device, an interface to receive video data from a video content provider, and/or a computer graphics system for generating video data, or a combination of such sources. The video data may comprise one or more pictures. Video encoder 114 encodes the video data from video source 112 to generate a bitstream. The bitstream may include a sequence of bits that form a coded representation of the video data. The bitstream may include coded pictures and associated data. The coded picture is a coded representation of a picture. The associated data may include sequence parameter sets, picture parameter sets, and other syntax structures. I/O interface 116 may include a modulator/demodulator (modem) and/or a transmitter. The encoded video data may be transmitted directly to destination device 120 via I/O interface 116 through network 130a. The encoded video data may also be stored onto a storage medium/server 130b for access by destination device 120.
Destination device 120 may include an I/O interface 126, a video decoder 124, and a display device 122.
I/O interface 126 may include a receiver and/or a modem. I/O interface 126 may acquire encoded video data from the source device 110 or the storage medium/server 130b. Video decoder 124 may decode the encoded video data. Display device 122 may display the decoded video data to a user. Display device 122 may be integrated with the destination device 120, or may be external to destination device 120 which be configured to interface with an external display device.
Video encoder 114 and video decoder 124 may operate according to a video compression standard, such as the High Efficiency Video Coding (HEVC) standard, Versatile Video Coding (VVM) standard and other current and/or further standards.
Video encoder 200 may be configured to perform any or all of the techniques of this disclosure. In the example of
The functional components of video encoder 200 may include a partition unit 201, a prediction unit 202 which may include a mode select unit 203, a motion estimation unit 204, a motion compensation unit 205 and an intra 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 encoding unit 214.
In other examples, video encoder 200 may include more, fewer, or different functional components. In an example, prediction unit 202 may include an intra block copy (IBC) unit. The IBC unit may perform prediction in an IBC mode in which at least one reference picture is a picture where the current video block is located.
Furthermore, some components, such as motion estimation unit 204 and motion compensation unit 205 may be highly integrated, but are represented in the example of
Partition unit 201 may partition a picture into one or more video blocks. Video encoder 200 and video decoder 300 may support various video block sizes.
Mode select unit 203 may select one of the coding modes, intra or inter, e.g., based on error results, and provide the resulting intra- or inter-coded block to a residual generation unit 207 to generate residual block data and to a reconstruction unit 212 to reconstruct the encoded block for use as a reference picture. In some example, Mode select unit 203 may select a combination of intra and inter prediction (CIIP) mode in which the prediction is based on an inter prediction signal and an intra prediction signal. Mode select unit 203 may also select a resolution for a motion vector (e.g., a sub-pixel or integer pixel precision) for the block in the case of inter-prediction.
To perform inter prediction on a current video block, motion estimation unit 204 may generate motion information for the current video block by comparing one or more reference frames from buffer 213 to the current video block. Motion compensation unit 205 may determine a predicted video block for the current video block based on the motion information and decoded samples of pictures from buffer 213 other than the picture associated with the current video block.
Motion estimation unit 204 and motion compensation unit 205 may perform different operations for a current video block, for example, depending on whether the current video block is in an I slice, a P slice, or a B slice.
In some examples, motion estimation unit 204 may perform uni-directional prediction for the current video block, and motion estimation unit 204 may search reference pictures of list 0 or list 1 for a reference video block for the current video block. Motion estimation unit 204 may then generate a reference index that indicates the reference picture in list 0 or list 1 that contains the reference video block and a motion vector that indicates a spatial displacement between the current video block and the reference video block. Motion estimation unit 204 may output the reference index, a prediction direction indicator, and the motion vector as the motion information of the current video block. Motion compensation unit 205 may generate the predicted video block of the current block based on the reference video block indicated by the motion information of the current video block.
In other examples, motion estimation unit 204 may perform bi-directional prediction for the current video block, motion estimation unit 204 may search the reference pictures in list 0 for a reference video block for the current video block and may also search the reference pictures in list 1 for another reference video block for the current video block. Motion estimation unit 204 may then generate reference indexes that indicate the reference pictures in list 0 and list 1 containing the reference video blocks and motion vectors that indicate spatial displacements between the reference video blocks and the current video block. Motion estimation unit 204 may output the reference indexes and the motion vectors of the current video block as the motion information of the current video block. Motion compensation unit 205 may generate the predicted video block of the current video block based on the reference video blocks indicated by the motion information of the current video block.
In some examples, motion estimation unit 204 may output a full set of motion information for decoding processing of a decoder.
In some examples, motion estimation unit 204 may do not output a full set of motion information for the current video. Rather, 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.
In one example, motion estimation unit 204 may indicate, in a syntax structure associated with the current video block, a value that indicates to the video decoder 300 that the current video block has the same motion information as the another video block.
In another example, motion estimation unit 204 may identify, in a syntax structure associated with the current video block, another video block and a motion vector difference (MVD). The motion vector difference indicates a 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.
As discussed above, video encoder 200 may predictively signal the motion vector. Two examples of predictive signaling techniques that may be implemented by video encoder 200 include advanced motion vector prediction (AMVP) and merge mode signaling.
Intra prediction unit 206 may perform intra prediction on the current video block. When intra prediction unit 206 performs intra prediction on the current video block, 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.
Residual generation unit 207 may generate residual data for the current video block by subtracting (e.g., indicated by the minus sign) the predicted video block(s) of the current video block from the current video block. The residual data of the current video block may include residual video blocks that correspond to different sample components of the samples in the current video block.
In other examples, there may be no residual data for the current video block for the current video block, for example in a skip mode, and residual generation unit 207 may not perform the subtracting operation.
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 a residual video block associated with the current video block.
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.
Inverse quantization unit 210 and inverse transform unit 211 may apply inverse quantization and inverse transforms to the transform coefficient video block, respectively, to reconstruct a residual video block from the transform coefficient video block. Reconstruction unit 212 may add the reconstructed residual video block to corresponding samples from one or more predicted video blocks generated by the prediction unit 202 to produce a reconstructed video block associated with the current block for storage in the buffer 213.
After reconstruction unit 212 reconstructs the video block, loop filtering operation may be performed reduce video blocking artifacts in the video block.
Entropy encoding unit 214 may receive data from other functional components of the video encoder 200. When entropy encoding unit 214 receives the data, entropy encoding unit 214 may perform one or more entropy encoding operations to generate entropy encoded data and output a bitstream that includes the entropy encoded data.
Some embodiments of the disclosed technology include making a decision or determination to enable a video processing tool or mode. In an example, when the video processing tool or mode is enabled, the encoder will use or implement the tool or mode in the processing of a block of video, but may not necessarily modify the resulting bitstream based on the usage of the tool or mode. That is, a conversion from the block of video to the bitstream of the video will use the video processing tool or mode when it is enabled based on the decision or determination. In another example, when the video processing tool or mode is enabled, the decoder will process the bitstream with the knowledge that the bitstream has been modified based on the video processing tool or mode. That is, a conversion from the bitstream of the video to the block of video will be performed using the video processing tool or mode that was enabled based on the decision or determination.
The video decoder 300 may be configured to perform any or all of the techniques of this disclosure. In the example of
In the example of
Entropy decoding unit 301 may retrieve an encoded bitstream. The encoded bitstream may include entropy coded video data (e.g., encoded blocks of video data). Entropy decoding unit 301 may decode the entropy coded video data, and from the entropy decoded video data, motion compensation unit 302 may determine motion information including motion vectors, motion vector precision, reference picture list indexes, and other motion information. Motion compensation unit 302 may, for example, determine such information by performing the AMVP and merge mode.
Motion compensation unit 302 may produce motion compensated blocks, possibly performing interpolation based on interpolation filters. Identifiers for interpolation filters to be used with sub-pixel precision may be included in the syntax elements.
Motion compensation unit 302 may use interpolation filters as used by video encoder 20 during encoding of the video block to calculate interpolated values for sub-integer pixels of a reference block. Motion compensation unit 302 may determine the interpolation filters used by video encoder 200 according to received syntax information and use the interpolation filters to produce predictive blocks.
Motion compensation unit 302 may uses some of the syntax information to determine sizes of blocks used to encode frame(s) and/or slice(s) of the encoded video sequence, partition information that describes how each macroblock of a picture of the encoded video sequence is partitioned, modes indicating how each partition is encoded, one or more reference frames (and reference frame lists) for each inter-encoded block, and other information to decode the encoded video sequence.
Intra prediction unit 303 may use intra prediction modes for example received in the bitstream to form a prediction block from spatially adjacent blocks. Inverse quantization unit 303 inverse quantizes, i.e., de-quantizes, the quantized video block coefficients provided in the bitstream and decoded by entropy decoding unit 301. Inverse transform unit 303 applies an inverse transform.
The reconstruction unit 306 may sum the residual blocks with the corresponding prediction blocks generated by motion compensation unit 202 or intra-prediction unit 303 to form decoded blocks. If desired, a deblocking filter may also be applied to filter the decoded blocks in order to remove blockiness artifacts. The decoded video blocks are then stored in buffer 307, which provides reference blocks for subsequent motion compensation/intra prediction and also produces decoded video for presentation on a display device.
The system 1900 may include a coding component 1904 that may implement the various coding or encoding methods described in the present document. The coding component 1904 may reduce the average bitrate of video from the input 1902 to the output of the coding component 1904 to produce a bitstream representation of the video. The coding techniques are therefore sometimes called video compression or video transcoding techniques. The output of the coding component 1904 may be either stored, or transmitted via a communication connected, as represented by the component 1906. The stored or communicated bitstream (or coded) representation of the video received at the input 1902 may be used by the component 1908 for generating pixel values or displayable video that is sent to a display interface 1910. The process of generating user-viewable video from the bitstream is sometimes called video decompression. Furthermore, while certain video processing operations are referred to as “coding” operations or tools, it will be appreciated that the coding tools or operations are used at an encoder and corresponding decoding tools or operations that reverse the results of the coding will be performed by a decoder.
Examples of a peripheral bus interface or a display interface may include universal serial bus (USB) or high definition multimedia interface (HDMI) or Displayport, and so on. Examples of storage interfaces include SATA serial advanced technology attachment (SATA), Peripheral Component Interconnect (PCI), Integrated Drive Electronics (IDE) interface, and the like. The techniques described in the present document may be embodied in various electronic devices such as mobile phones, laptops, smartphones or other devices that are capable of performing digital data processing and/or video display.
In some embodiments of method 2200, when the ALF mode is enabled for the video unit, a color space conversion is performed on residual values of the video unit. In some embodiments of method 2200, when the CC-ALF tool is enabled for the video unit, sample values of the video unit of a video component are filtered with sample values of another video component of the video. In some embodiments of method 2200, the rule specifies that a first syntax element selectively included in the bitstream indicates whether the CC-ALF mode is enabled for the video unit. In some embodiments of method 2200, the first syntax element is indicated in a sequence level or a video level or a picture level associated with the video unit, and the first syntax element is different from another syntax element included in the bitstream that indicates whether the ALF mode is enabled for the video unit. In some embodiments of method 2200, the first syntax element is included in the bitstream based on the ALF mode being enabled for the video unit.
In some embodiments of method 2200, the first syntax element is included in the bitstream in case that a coding condition is met, wherein the coding condition comprises: a type of color format of the video, or whether separate plane coding is enabled for the conversion, or a sampling structure of a chroma component of the video. In some embodiments of method 2200, the rule specifies that the bitstream includes a second syntax element that indicates whether one or more syntax elements related to the CC-ALF mode are present in a picture header, and where the second syntax element is included in the picture header or a picture parameter set (PPS) or a slice header. In some embodiments of method 2200, the rule specifies that the bitstream includes the second syntax element based on the ALF mode being enabled for the video unit.
In some embodiments of method 2200, the ALF is a Weiner filter with neighboring samples as input. In some embodiments of method 2200, the rule specifies that the bitstream includes syntax elements in a picture header or in a picture parameter set (PPS) related to the CC-ALF mode when: a value for a chroma array time is not equal to zero or a color format of the video is not 4:0:0, and the bitstream includes a first syntax element that indicates that the CC-ALF mode is enabled for the video unit, wherein the first syntax element is indicated for a video level of the video that is higher than that of the video unit. In some embodiments of method 2200, the rule specifies that the bitstream includes syntax elements in a picture header or in a picture parameter set (PPS) or in a slice header related to the CC-ALF mode when: a value for a chroma array time is not equal to zero or a color format of the video is not 4:0:0, or the bitstream includes a first syntax element that indicates that the CC-ALF mode is enabled for the video unit, wherein the first syntax element is indicated for a video level of the video that is higher than that of the video unit. In some embodiments of method 2200, the video level includes a sequence parameter set (SPS).
In some embodiments of method 2300, the chroma component includes a Cb chroma component. In some embodiments of method 2300, the chroma component includes a Cr chroma component. In some embodiments of methods 2200-2300, the video unit comprises a coding unit (CU), a prediction unit (PU), or a transform unit (TU). In some embodiments of methods 2200-2300, the performing the conversion comprising encoding the video into the bitstream. In some embodiments of methods 2200-2300, the performing the conversion comprises decoding the video from the bitstream. In some embodiments, a video decoding apparatus comprising a processor configured to implement techniques for embodiments related to methods 2200-2300. In some embodiments, a video encoding apparatus comprising a processor configured to implement techniques for embodiments related to methods 2200-2300. In some embodiments, a computer program product having computer instructions stored thereon, the instructions, when executed by a processor, causes the processor to implement techniques for embodiments related to methods 2200-2300. In some embodiments, a computer readable medium that stores a bitstream generated according to techniques for embodiments related to methods 2200-2300. In some embodiments, a video processing apparatus for storing a bitstream, wherein the video processing apparatus is configured to implement techniques for embodiments related to methods 2200-2300.
Some embodiments may be described using the following clause-based format. The first set of clauses show example embodiments of techniques discussed in the previous sections.
The items below are preferably implemented by some embodiments. Additional features are shown in the listing in the previous section, e.g., items 31-32.
The second set of clauses show example embodiments of techniques discussed in the previous sections (items 42-43).
The third set of clauses show example embodiments of techniques discussed in the previous sections (e.g., item 44).
In some embodiments, a solution includes a method, an apparatus, a bitstream generated according to an above-described method or a system for video processing is implemented.
The disclosed and other solutions, examples, embodiments, modules and the functional operations described in this document can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this document and their structural equivalents, or in combinations of one or more of them. The disclosed and other embodiments can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer readable medium for execution by, or to control the operation of, data processing apparatus. The computer readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of matter effecting a machine-readable propagated signal, or a combination of one or more them. The term “data processing apparatus” encompasses all apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, or multiple processors or computers. The apparatus can include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., 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 propagated signal is an artificially generated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal, that is generated to encode information for transmission to suitable receiver apparatus.
A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.
The processes and logic flows described in this document can be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).
Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read only memory or a random-access memory or both. The essential elements of a computer are a processor for performing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto optical disks, or optical disks. However, a computer need not have such devices. Computer readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., erasable programmable read-only memory (EPROM), electrically EPROM (EEPROM), and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto optical disks; and compact disc read-only memory (CD ROM) and digital versatile disc read-only memory (DVD-ROM) disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.
While this patent document contains many specifics, these should not be construed as limitations on the scope of any subject matter or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular techniques. Certain features that are described in this patent document in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.
Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Moreover, 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.
Only a few implementations and examples are described and other implementations, enhancements and variations can be made based on what is described and illustrated in this patent document.
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/CN2020/070001 | Jan 2020 | WO | international |
This application is a continuation of U.S. application Ser. No. 17/856,631, filed on Jul. 1, 2022, which is a continuation of International Patent Application No. PCT/US2020/067651, filed on Dec. 31, 2020, which claims the priority to and benefits of International Patent Application No. PCT/CN2020/070001, filed on Jan. 1, 2020. All the aforementioned patent applications are hereby incorporated by reference in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17856631 | Jul 2022 | US |
| Child | 18498652 | US | |
| Parent | PCT/US2020/067651 | Dec 2020 | US |
| Child | 17856631 | US |
