WO2020065569A1 - Mode dependent affine inheritance - Google Patents

Abstract

A method of video processing includes determining an affine model of a neighboringblock adjacent to a current block; deriving control point motion vectors of the currentblock from the neighboring block at least based on one of the affine model of theneighboring block and a location of the neighboring block relative to the current block;and performing a video processing between the current block and a bitstreamrepresentation of the current block based on the control point motion vectors.

Description

MODE DEPENDENT AFFINE INHERITANCE

[0001] Under the applicable patent law and/or rules pursuant to the Paris Convention, this application is made to timely claim the priority to and benefits of International Patent Application No. PCT/CN2018/107629, filed on September 26, 2018 and International Patent Application No. PCT/CN2018/107869, filed on September 27, 2018. The entire disclosures of International Patent Application No. PCT/CN2018/107629 and International Patent Application No. PCT/CN2018/107869, are incorporated by reference as part of the disclosure of this application.

TECHNICAL FIELD

[0002] This patent document relates to video coding techniques, devices and systems.

BACKGROUND

[0003] Motion compensation (MC) is a technique in video processing to predict a frame in a video, given the previous and/or future frames by accounting for motion of the camera and/or objects in the video. Motion compensation can be used in the encoding of video data for video compression.

SUMMARY

[0004] This document discloses methods, systems, and devices related to the use of affine motion compensation in video coding and decoding.

[0005] In one example aspect, a method of video processing is disclosed. The method comprises determining an affine model of a neighboring block adjacent to a current block; deriving control point motion vectors of the current block from the neighboring block at least based on one of the affine model of the neighboring block and a location of the neighboring block relative to the current block; and performing a video processing between the current block and a bitstream representation of the current block based on the control point motion vectors.

[0006] A video processing apparatus comprising a processor configured to implement the methods described herein.

[0007] In yet another representative aspect, the various techniques described herein may be embodied as a computer program product stored on a non-transitory computer readable media. The computer program product includes program code for carrying out the methods described herein.

[0008] In yet another representative aspect, a video decoder apparatus may implement a method as described herein.

[0009] The details of one or more implementations are set forth in the accompanying attachments, the drawings, and the description below. Other features will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 shows an example of sub-block based prediction calculation.

[0011] FIG. 2A-2B shows examples of Simplified affine motion model (a) 4- parameter affine model; (b) 6-parameter affine model.

[0012] FIG. 3 shows an example of affine motion vector field (MVF) per subblock.

[0013] FIGS. 4A-4B show candidates for AF_MERGE mode.

[0014] FIG. 5 shows example candidate positions for affine merge mode.

[0015] FIG. 6 shows an example of a Coding Unit (CU) with four sub-blocks (A-D) and its neighbouring blocks (a-d).

[0016] Fig. 7 shows an example of affine inheritance by deriving from the two right CPs of a neighbouring block.

[0017] Fig. 8 Affine inheritance by deriving from the two right CPs of a neighbouring block.

[0018] Fig. 9 shows an example of 6-parameter affine inheritance by deriving from MVs stored in the bottom row of an affine coded above neighbouring block.

[0019] FIG. 10 shows an example of bottom row of basic unit blocks(shaded) that can store the auxiliary MV.

[0020] FIG. 1 1 shows an example of 6-parameter affine inheritance by deriving from MVs stored in the right column of an affine coded left neighbouring block.

[0021] FIG. 12 shows an example of the right column of basic unit blocks(shaded) that can store the auxiliary MV.

[0022] FIG. 13 shows an example of MV storage used.

[0023] FIG. 14 is a block diagram illustrating an example of the architecture for a computer system or other control device that can be utilized to implement various portions of the presently disclosed technology.

[0024] FIG. 15 shows a block diagram of an example embodiment of a mobile device that can be utilized to implement various portions of the presently disclosed technology.

[0025] FIG. 16 is a flowchart for an example method of visual media processing.

DETAILED DESCRIPTION

[0026] The present document provides several techniques that can be embodied into digital video encoders and decoders. Section headings are used in the present document for clarity of understanding and do not limit scope of the techniques and embodiments disclosed in each section only to that section.

[0027] 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 representation or vice versa.

[0028] 1. Summary

[0029] This invention is related to video/image coding technologies. Specifically, it is related to affine prediction in video/image coding. It may be applied to the existing video coding standard like HEVC, or the standard (Versatile Video Coding) to be finalized. It may be also applicable to future video/image coding standards or video/image codec.

[0030] 2. Introduction

[0031] Sub-block based prediction is first introduced into the video coding standard by HEVC Annex I (3D-HEVC). With sub-block based prediction, a block, such as a Coding Unit (CU) or a Prediction Unit (PU), is divided into several non-overlapped sub blocks. Different sub-block may be assigned different motion information, such as reference index or Motion Vector (MV), and Motion Compensation (MC) is performed individually for each sub-block. FIG. 1 shows the concept of sub-block based prediction.

[0032] 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).

[0033] In JEM, sub-block based prediction is adopted in several coding tools, such as affine prediction, Alternative temporal motion vector prediction (ATMVP), spatial-temporal motion vector prediction (STMVP), Bi-directional Optical flow (BIO) and Frame-Rate Up Conversion (FRUC). Affine prediction has also been adopted into VVC.

2.1 Affine Prediction

[0034] In FIEVC, only translation motion model is applied for motion compensation prediction (MCP). While in the real world, there are many kinds of motion, e.g. zoom in/out, rotation, perspective motions and the other irregular motions. In the VVC, a simplified affine transform motion compensation prediction is applied. As shown in FIG. 2A-2B, the affine motion field of the block is described by two (in the 4-parameter affine model) or three (in the 6-parameter affine model) control point motion vectors.

[0035] Fig. 2A-2B shows a simplified affine motion model (a) 4-parameter affine model; (b) 6-parameter affine model

[0036] The motion vector field (MVF) of a block is described by the following equation with the 4-parameter affine model

mvj

(1 )

mv₀ ^v

and 6-parameter affine model:

[0037] where (mi/o, mv^v ₀) is motion vector of the top-left corner control point, and (miA, mv^vi) is motion vector of the top-right corner control point and

m v^v ₂) is motion vector of the bottom-left corner control, point(x, y) represents the coordinate of a representative point relative to the top-left sample within current block. The CP motion vectors may be signaled (like in the affine AMVP mode) or derived on-the-fly (like in the affine merge mode) w and h are the width and height of the current block. In practice, the division is implemented by right-shift with a rounding operation. In VTM, the

representative point is defined to be the center position of a sub-block, e.g., when the coordinate of the left-top corner of a sub-block relative to the top-left sample within current block is (xs, ys), the coordinate of the representative point is defined to be (xs+2, ys+2).

[0038] In a division-free design, (1 ) and (2) are implemented as

J iDMvHorX = (mv(‘ - mv^ ) « (S - log 2(w))

[iDMvHorY = (mv₁ ^v - mv₀ ^v ) « (S -log 2(w))

(3)

[0039] For the 4-parameter affine model shown in (1 ) :

JiDMvVerX = -iDMvHorY

I iDMvVerY = iDMvHorX

(4)

[0040] For the 6-parameter affine model shown in (2):

JiDMvVerX = (mvj - mv0' ) « (5 - log 2(h))

[iDMvVerY = ( mv₂ ^v - mv₀ ^v ) « (S -log 2(/z))

(5)

[0041] Finally,

[0042] where S represents the calculation precision e.g. in VVC, S= 7. In VVC, the MV used in MC for a sub-block with the top-left sample at (xs, ys) is calculated by (6) with x=xs+2 and y=ys+2.

[0043] To derive motion vector of each 4x4 sub-block, the motion vector of the center sample of each sub-block, as shown in FIG. 3, is calculated according to Eq. (1 ) or (2), and rounded to 1/16 fraction accuracy. Then the motion compensation interpolation filters are applied to generate the prediction of each sub-block with derived motion vector.

[0044] Affine model can be inherited from spatial neighbouring affine-coded block such as left, above, above right, left bottom and above left neighbouring block as shown in FIG. 4A. For example, if the neighbour left block A in FIG. 4A is coded in affine mode as denoted by A0 in FIG. 4B., the Control Point (CP) motion vectors mv₀ ^N, mv i^N and mv₂ ^N of the top left corner, above right corner and left bottom corner of the neighbouring CU/PU which contains the block A are fetched. And the motion vector mv_Q ^c, mv i^c and mv₂ ^c (which is only used for the 6-parameter affine model) of the top left corner/top right/bottom left on the current CU/PU is calculated based on mv₀ ^N, mv i^N and mv₂ ^N. It should be noted that in VTM-2.0, sub-block (e.g. 4x4 block in VTM) LT stores mvO, RT stores mv1 if the current block is affine coded. If the current block is coded with the 6- parameter affine model, LB stores mv2; otherwise (with the 4-parameter affine model), LB stores mv2’. Other sub-blocks stores the MVs used for MC.

[0045] It should be noted that when a CU is coded with affine merge mode, i.e. , in AF_MERGE mode, it gets the first block coded with affine mode from the valid neighbour reconstructed blocks. And the selection order for the candidate block is from left, above, above right, left bottom to above left as shown FIG. 4A.

[0046] The derived CP MVs mv_Q ^c, mv i^c and mv₂ ^c of current block can be used as CP MVs in the affine merge mode. Or they can be used as MVP for affine inter mode in VVC. It should be noted that for the merge mode, if the current block is coded with affine mode, after deriving CP MVs of current block, the current block may be further split into multiple sub-blocks and each block will derive its motion information based on the derived CP MVs of current block.

2.2 JVET-K0186

[0047] Different from VTM wherein only one affine spatial neighboring block may be used to derive affine motion for a block, in JVET-K0186, it proposes to construct a separate list of affine candidates for the AF_MERGE mode. The following steps are performed.

1 ) Insert inherited affine candidates into candidate list [0048] Fig. 5 shows examples of candidate position for affine merge mode.

[0049] Inherited affine candidate means that the candidate is derived from the valid neighbor reconstructed block coded with affine mode.

[0050] As shown in FIG. 5, the scan order for the candidate block is Ai , Bi, B₀, A₀ and B₂. When a block is selected (e.g., Ai), the two-step procedure is applied:

a) Firstly, use the three corner motion vectors of the CU covering the block to

derive two/three control points of current block

b) Based on the control points of current block to derive sub-block motion for each sub-block within current block

2) Insert constructed affine candidates

[0051] If the number of candidates in affine merge candidate list is less than

MaxNumAffineCand, constructed affine candidates are insert into the candidate list.

[0052] Constructed affine candidate means the candidate is constructed by combining the neighbor motion information of each control point.

[0053] The motion information for the control points is derived firstly from the specified spatial neighbors and temporal neighbor shown in FIG. 5. CPk (k=1 , 2, 3, 4) represents the k-th control point. A₀, Ai, A₂, B₀, Bi , B₂ and B₃ are spatial positions for predicting CPk (k=1 , 2, 3); T is temporal position for predicting CP4.

[0054] The coordinates of CP1 , CP2, CP3 and CP4 is (0, 0), (W, 0), (H, 0) and (W, H), respectively, where W and H are the width and height of current block.

[0055] The motion information of each control point is obtained according to the following priority order:

- For CP1 , the checking priority is B₂->B₃->A₂. B₂ is used if it is available.

Otherwise, if B₂ is unavailable, B₃ is used. If both B₂ and B₃ are unavailable, A₂ is used. If all the three candidates are unavailable, the motion information of CP1 cannot be obtained.

- For CP2, the checking priority is B1 ->B0;

- For CP3, the checking priority is A1 ->A0;

- For CP4, T is used.

[0056] Secondly, the combinations of controls points are used to construct the motion model.

[0057] Motion vectors of three control points are needed to compute the transform parameters in 6-parameter affine model. The three control points can be selected from one of the following four combinations ({CP1 , CP2, CP4}, {CP1 , CP2, CP3}, {CP2, CP3, CP4}, {CP1 , CP3, CP4}). For example, use CP1 , CP2 and CP3 control points to construct 6-parameter affine motion model, denoted as Affine (CP1 , CP2, CP3).

[0058] Motion vectors of two control points are needed to compute the transform parameters in 4-parameter affine model. The two control points can be selected from one of the following six combinations ({CP1 , CP4}, {CP2, CP3}, {CP1 , CP2}, {CP2,

CP4}, {CP1 , CP3}, {CP3, CP4}). For example, use the CP1 and CP2 control points to construct 4-parameter affine motion model, denoted as Affine (CP1 , CP2).

[0059] The combinations of constructed affine candidates are inserted into to candidate list as following order:

{CP1 , CP2, CP3}, {CP1 , CP2, CP4}, {CP1 , CP3, CP4}, {CP2, CP3, CP4}, {CP1 , CP2}, {CP1 , CP3}, {CP2, CP3}, {CP1 , CP4}, {CP2, CP4}, {CP3, CP4}

3) Insert zero motion vectors

[0060] If the number of candidates in affine merge candidate list is less than

MaxNumAffineCand, zero motion vectors are insert into the candidate list, until the list is full.

2.3 ATMVP (advanced temporal motion vector prediction)

[0061] At the 10th JVET meeting, advanced temporal motion vector prediction (ATMVP) was included in the benchmark set (BMS)-1 .0 reference software, which derives multiple motion for sub-blocks of one coding unit (CU) based on the motion information of the collocated blocks from temporal neighboring pictures. Although it improves the efficiency of temporal motion vector prediction, the following complexity issues are identified for the existing ATMVP design:

[0062] The collocated pictures of different ATMVP CUs may not be the same if multiple reference pictures are used. This means the motion fields of multiple reference pictures need to be fetched.

[0063] The motion information of each ATMVP CU is always derived based on 4x4 units, resulting in multiple invocations of motion derivation and motion compensation for each 4x4 sub-block inside one ATMVP CU.

[0064] Some further simplifications on ATMVP were proposed and have been adopted in VTM2.0. 2.3.1 Simplified collocated block derivation with one fixed collocated picture

[0065] In this method, one simplified design is proposed to use the same collocated picture as in HEVC, which is signaled at the slice header, as the collocated picture for ATMVP derivation. At the block level, if the reference picture of a neighboring block is different from this collocated picture, the MV of the block is scaled using the HEVC temporal MV scaling method, and the scaled MV is used in ATMVP.

[0066] Denote the motion vector used to fetch the motion field in the collocated picture R_COi as MV_C0|. To minimize the impact due to MV scaling, the MV in the spatial candidate list used to derive MV_COi is selected in the following way: if the reference picture of a candidate MV is the collocated picture, this MV is selected and used as MVcoi without any scaling. Otherwise, the MV having a reference picture closest to the collocated picture is selected to derive MV_COi with scaling.

2.3.2 Adaptive ATMVP sub-block size

[0067] In this method, it is proposed to support the slice-level adaptation of the sub block size for the ATMVP motion derivation. Specifically, one default sub-block size that is used for the ATMVP motion derivation is signaled at sequence level. Additionally, one flag is signaled at slice-level to indicate if the default sub-block size is used for the current slice. If the flag is false, the corresponding ATMVP sub-block size is further signaled in the slice header for the slice.

2.4 STMVP (Spatial-temporal motion vector prediction)

[0068] STMVP was proposed and adopted in JEM, but not in VVC yet. In STMVP, the motion vectors of the sub-CUs are derived recursively, following raster scan order. Fig. 6. illustrates this concept. Let us consider an 8x8 CU which contains four 4x4 sub- CUs A, B, C, and D. The neighbouring 4x4 blocks in the current frame are labelled as a, b, c, and d.

[0069] The motion derivation for sub-CU A starts by identifying its two spatial neighbours. The first neighbour is the NxN block above sub-CU A (block c). If this block c is not available or is intra coded the other Nx N blocks above sub-CU A are checked (from left to right, starting at block c). The second neighbour is a block to the left of the sub-CU A (block b). If block b is not available or is intra coded other blocks to the left of sub-CU A are checked (from top to bottom, staring at block b). The motion information obtained from the neighbouring blocks for each list is scaled to the first reference frame for a given list. Next, temporal motion vector predictor (TMVP) of sub-block A is derived by following the same procedure of TMVP derivation as specified in HEVC. The motion information of the collocated block at location D is fetched and scaled accordingly.

Finally, after retrieving and scaling the motion information, all available motion vectors (up to 3) are averaged separately for each reference list. The averaged motion vector is assigned as the motion vector of the current sub-CU.

[0070] FIG. 6 shows an example of one CU with four sub-blocks (A-D) and its neighbouring blocks (a-d).

2.5 Example affine inheritance methods

[0071] To reduce the memory requirement by affine model inheritance, some embodiments may implement a scheme in which the affine model is inheirted by only accessing one line of MVs left to the current block and one line of MVs above the current block.

[0072] The affine model inheritance can be conducted bv deriving the CP MVs of the current block from the bottom-left MV and bottom-right MV of the affine-coded

neighbouring block as shown in Fig. 7.

a. In one example, mv₀ ^c =( mv₀ ^Ch, mv₀ ^Cv) and mv i^c =( mv ^h, mv i^are derived from mv₀ ^N =( mv₀ ^Nh, mv ₀ ^Nv) and mv i^N =( mv ^Nh, mv i^Wl as:

where w and W are the width of the current block and the width of the neighbouring block, respectively. (x₀, yo) is the coordinate of the top-left corner of the current block and (x’₀, y’₀) is the coordinate of the bottom-left corner of the neighbouirng block.

Alternatively, furthermore, the division operation in a and b calculation process could be replaced by shift with or without adding operations. b. For example, the affine model inheritance is conducted by deriving the CP MVs of the current block from the bottom-left MV and bottom-right MV of the affine-coded neighbouring block coming from“B” and“C” in FIG. 4A. i. Alternatively, the affine model inheritance is conducted by deriving the CP MVs of the current block from the bottom-left MV and bottom-right MV of the affine-coded neighbouring block coming from“B”,“C” and“E” in FIG. 4A.

c. For example, the affine model inheritance is conducted by deriving the CP MVs of the current block from the bottom-left MV and bottom-right MV of the affine-coded neighbouring block only if the neighbouring block is in a Mx N region that is above ( or above-right, or above-left ) to the MxN region containing the current block.

d. For example, y₀ = y’o·

i. Alternatively, y₀ = 1 +/o·

e. For example, if the current block inherits affine model by deriving the CP MVs of the current block from the bottom-left MV and bottom-right MV of the affine-coded neighbouring block, then the current block is regarded as using the 4-parameter affine model.

[0073] Fig. 7 shows an example of affine inheritance by deriving from the two bottom CPs of a neighbouring block.

[0074] The affine model inheritance can be conducted by deriving the CP MVs of the current block from the top-right MV and bottom-right MV of the affine-coded

neighbouring block as shown in Fig. 8.

a. For example, mv₀ ^c =( mv₀ ^Ch, mv₀ ^Cv) and mv i^c =( mv^ ^Ch, mv i^Cl are derived from mv₀ ^N =( mv₀ ^Nh, mv ₀ ^Nv) and mv i^N =( mv-_\ ^Nh, mv-_\ ^Nv) as:

where h’ is the height of the neighbouring block w is the width of the current block. (x₀, y₀) is the coordinate of the top-left corner of the current block and (x’o, y’o) is the coordinate of the top-right corner of the neighbouirng block.

Alternatively, furthermore, the division operation in a and b calculation process could be replaced by shift with or without adding operations. b. For example, the affine model inheritance is conducted by deriving the CP MVs of the current block from the top-right MV and bottom-right MV of the affine-coded neighbouring block coming from“A” and“D” in FIG. 4A.

i. Alternatively, the affine model inheritance is conducted by deriving the CP MVs of the current block from the top-right MV and bottom- right MV of the affine-coded neighbouring block coming from“A”,“D” and“E” in Fig. 4A.

c. For example, the affine model inheritance is conducted by deriving the CP MVs of the current block from the top-right MV and bottom-right MV of the affine-coded neighbouring block only if the neighbouring block is in a MxN region that is left ( or above-left, or bottom-left ) to the MxN region containing the current block.

d. For example, x₀ = x

ii. Alternatively, XQ = 1 +x o.

e. For example, if the current block inherits affine model by deriving the CP MVs of the current block from the top-right MV and bottom-right MV of the affine-coded neighbouring block, then the current block is regared as using the 4-parameter affine model.

[0075] More CP MVs mav be derived and stored for motion vector prediction and/or filtering process if the current block does not use the 6-parameter affine model.

a. In one example, the stored left-bottom MV can be used in motion prediction including affine model inheritance for following coded PU/CUs.

b. In one example, the stored left-bottom MV can be used in motion prediction of succeeding pictures.

c. In one example, the stored left-bottom MV can be used in the deblocking filtering process.

d. If an affine coded block does not use the 6-parameter affine model, the CP MV of the left-bottom corner is derived for the affine coded block and is stored in the left-bottom MV unit, which is 4x4 in VVC.

i. The CP MV (noted as mv₂=( rnv₂ ^h, mv₂ ) ) of the left-bottom corner is derived for the 4-paramter affine model as

e. The CP MV of the right-bottom corner is derived for an affine coded block and is stored in the right-bottom MV unit, which is 4x4 in VVC. The stored right-bottom MV can be used in motion prediction including affine model inheritance for following coded PU/CUs, or motion prediction of succeeding pictures or deblocking filtering process. The CP MV (noted as mv₃=( mv₃ ^h, mv^ ) ) of the right-bottom corner is derived for the 4-paramter affine model as

The CP MV of the right-bottom corner is derived for the 6-paramter affine model as

er is derived for both the 4-paramter affine model and the 6-paramter affine model as

a. f mv_{2 = mv* +} mv_{2 -} mv^

I (13)

inv = IIIV: + inv - inw:

if mv₂=( mv₂ ^h, mv₂ ^v) in the 4-parameter model is calculated as (10)

[0076] Fig. 8 shows an example of affine inheritance by deriving from the two right CPs of a neighbouring block.

3. Problems solved by the embodiments

[0077] Some previous designs can only support inheritance of 4-paramter affine model, which may incur a coding performance loss when 6-parameter affine model is enabled.

4. Example embodiments

[0078] We propose several methods to inherit the 6-parameter affine model with reduced memory requirements.

[0079] The detailed inventions below should be considered as examples to explain general concepts. These inventions should not be interpreted in a narrow way.

Furthermore, these inventions can be combined in any manner. Combination between this invention and other invention is also applicable.

[0080] In the discussions below, suppose the coordinate of the top-left corner/top- right corner/bottom-left corner/bottom-right corner of the affine coded above or left neighbouring CU are (LTNx,LTNy)/(RTNx, RTNy)/(LBNx, LBNy)/(RBNx, RBNy), respectively; the coordinate of the top-left corner/top-right corner/bottom-left corner/bottom-right corner of the currernt CU are (LTCx,LTCy)/(RTCx, RTCy)/(LBCx, LBCy)/(RBCx, RBCy), respectively; the width and height of the affine coded above or left neighbouring CU are w’ and h’, respectively; the width and height of the affine coded current CU are w and h, respectively.

1 . The affine model inheritance is conducted by utilizing MVs in a line directly above the current block (e.g., MVs associated with blocks adjacent to the current block) in different ways depending on whether the affine coded above neighbouring block employs the 4-paramter affine model or the 6-parameter affine model.

a. In one example, the inheritance methods are applied when the affine coded above neighbouring CU employs the 4-paramter affine model.

b. In one example, the 6-parameter affine model inheritance can be conducted by deriving the CPMVs of the current block from the bottom-left MV and bottom-right MV of the affine-coded above neighbouring block, and one auxiliary MV as shown in Fig. 9 (i.e. , mv_Q ^N , mv i^w and the auxiliary MV associated with the auxiliary point), if the affine-coded above neighbouring block employs the 6-parameter affine model.

i. In one example, the proposed 6-parameter affine model inheritance can only be done if the affine-coded above neighbouring block employs the 6-parameter affine model and w’ > ThO (e.g., ThO is 8) ii. Alternatively, the proposed 6-parameter affine model inheritance may be invoked when the above block is coded with affine mode regardless it is 4 or 6 -parameter affine mode.

c. In one example, the auxiliary MV is derived by the affine model of the affine-coded above neighbouring block, with an auxiliary position.

i. The auxiliary position is predefined;

ii. Alternatively, the auxiliary position is adaptive. For example, the auxiliary position depends on the dimensions of the above neighbouring block.

iii. Alternatively, the auxiliary position is signaled from the encoder to the decoder in VPS/SPS/PPS/slice header/CTU/CU.

iv. Alternatively, the auxiliary position is (LTNx +(w’»1 ), LTNy + h’+ Offset). Offset is an integer. For example, Offset=2^K. In another example, Offset = -2^K. In some examples, K can be 1 , 2, 3, 4, or 5. Specifically, the auxiliary position is (LTNx + (w’»1 ), LTNy + h’ + 8). v. The auxiliary MV is stored in one of the bottom row of basic unit blocks (e.g. 4x4 block in VVC) of the affine-coded above neighbouring block as shown in Fig. 10. The basic unit block to store the auxiliary MV is named the auxiliary block.

(a) In one example, the auxiliary MV cannot be stored in the bottom-left and bottom-right corner basic unit block of the affine-coded above neighbouring block. (b) The bottom row of basic unit blocks are denoted as B(0), B(1 B(M-1 ) from left to right. In one example, the auxiliary MV is stored in the basic unit block B(M/2).

a. Alternatively, the auxiliary MV is stored in the basic unit block B(M/2+1 );

b. Alternatively, the auxiliary MV is stored in the basic unit block B(M/2-1 );

(c) In one example, the stored auxiliary MV can be used in motion prediction or merge for following coded PU/CUs.

(d) In one example, the stored auxiliary MV can be used in motion prediction or merge for succeeding pictures.

(e) In one example, the stored auxiliary MV can be used in the filtering process (e.g., deblocking filter).

(f) Alternatively, additional buffer may be utilized to store

auxiliary MVs instead of storing them in the basic unit blocks. In this case, the stored auxiliary MVs may be only used for affine motion inheritance, but not for coding following coded blocks in current slice/tile or different picture, and not for filtering process (e.g., deblocking filter)

vi. The auxiliary MV is calculated by Eq. (2) with the coordinate of the auxiliary position as the input (x,y) after decoding the affine-coded above neighbouring block. And then the auxiliary MV is stored in the auxiliary block.

(a) In one example, the MV stored in the auxiliary block is not used to do MC for the auxiliary block.

d. In one example as shown in Fig.9, the three CPMVs of the current block, denoted as mv₀ ^c =( mv₀ ^Ch, mv₀ ^Cv), mv i^C =( mv/^h, mv/') and mv₂ ^c =( mv₂ ^Ch, mv₂ ^Cv), are derived from mv₀ ^N =( mv₀ ^Nh, mv₀ ^Nv), which is the MV at the bottom-left corner of the affine coded above neighbouring block, mv / =( mv/^h, mv/), which is the MV at the bottom-right corner of the affine coded above neighbouring block, and mv_A =( mv_A ^h, mv/), which is the auxiliary MV, as

where (x₀, yo) is the coordinate of the top-left corner of the current block and (x’o, y’o) is the coordinate of the bottom-left corner of the neighbouring block.

Alternatively, furthermore, the division operation in (14) could be replaced by right shift with or without adding an offset before the shift.

i. For example, the number K in Eq(14) depends on how the auxiliary position is defined to get the auxiliary MV. In the example disclosed in l .c.iv, the auxiliary position is (LTNx+(w’»1 ), LTNy+h’+Offset) where Offset=2^K. In an example, K = 3.

e. For example, the affine model inheritance is conducted by deriving the CP MVs of the current block from the bottom-left MV and bottom-right MV of the affine-coded neighbouring block only if the neighbouring block is in a Mx N region that is above ( or above-right, or above-left ) to the MxN region containing the current block.

i. For example, Mx N region is a CTU, e.g. 128x 128 region;

ii. For example, Mx N region is the pipeline size, e.g. 64x64 region. f. For example, y₀ = y’o·

i. Alternatively, y₀ = 1 +/o·

Fig. 9 shows an example of 6-parameter affine inheritance by deriving from MVs stored in the bottom row of an affine coded above neighbouring block . Fig. 10 shows an example where the bottom row of basic unit blocks(shaded) that can store the auxiliary MV.

2. The affine model inheritance is conducted by utilizing MVs in a line left to the current block in different ways depending on whether the affine coded left neighbouring CU employs the 4-paramter affine model or the 6-parameter affine model.

a. In one example, the methods previously disclosed are applied when the affine coded left neighbouring CU employs the 4-paramter affine model. b. In one example, the 6-parameter affine model inheritance can be conducted by deriving the CPMVs of the current block from the top-right MV and bottom-right MV of the affine-coded left neighbouring block, and one auxiliary MV as shown in Fig. 1 1 , if the affine-coded left neighbouring block employs the 6-parameter affine model.

i. In one example, the 6-parameter affine model inheritance can only be done if the affine-coded left neighbouring block employs the 6- parameter affine model and h’ > Th1 (e.g., Th1 is 8) ii. Alternatively, the proposed 6-parameter affine model inheritance may be invoked when the left block is coded with affine mode regardless it is 4 or 6 -parameter affine mode.

c. In one example, the auxiliary MV is derived by the affine model of the affine-coded left neighbouring block, with an auxiliary position.

i. In one example, the auxiliary position is predefined;

ii. In one example, the auxiliary position is adaptive. For example, the auxiliary position depends on the dimensions of the left neighbouring block.

iii. In one example, the auxiliary position is signaled from the encoder to the decoder in VPS/SPS/PPS/slice header/CTU/CU.

iv. In one example, the auxiliary position is (LTNx+w’+Offset),

LTNy+(h’»1 )). Offset is an integer. For example, Offset=2^K. In another exmaple, Offset = -2^K. In some examples, K can be 1 , 2, 3, 4, or 5. Specifically, the auxiliary position is (LTNx+w’+8, LTNy+(h’>> 1 ))- v. The auxiliary MV is stored in one of the right column of basic unit blocks (e.g. 4x4 block in VVC) of the affine-coded left neighbouring block as shown in Fig. 1 2. The basic unit block to store the auxiliary MV is named the auxiliary block.

(a) In one example, the auxiliary MV cannot be stored in the top- right and bottom-right corner basic unit block of the affine- coded left neighbouring block.

(b) The right column of basic unit blocks are denoted as B(0), B(1 ),..., B(M-1 ) from top to bottom. In one example, the auxiliary MV is stored in the basic unit block B(M/2). a. Alternatively, the auxiliary MV is stored in the basic unit block B(M/2+1 );

b. Alternatively, the auxiliary MV is stored in the basic unit block B(M/2-1 );

(c) In one example, the stored auxiliary MV can be used in motion prediction or merge for following coded PU/CUs.

(d) In one example, the stored auxiliary MV can be used in motion prediction or merge for succeeding pictures.

(e) In one example, the stored auxiliary MV can be used in the filtering process (e.g., deblocking filter).

(f) Alternatively, additional buffer may be utilized to store auxiliary MVs instead of storing them in the basic unit blocks. In this case, the stored auxiliary MVs may be only used for affine motion inheritance, but not for coding following coded blocks in current slice/tile or different picture, and not for filtering process (e.g., deblocking filter)

vi. The auxiliary MV is calculated by Eq. (2) with the coordinate of the auxiliary position as the input (x,y) after decoding the affine-coded left neighbouring block. And then the auxiliary MV is sotred in the auxiliary block.

(a) In one example, the MV stored in the auxiliary block is not used to do MC for the auxiliary block.

d. In one example as shown in Fig.1 1 , the three CPMVs of the current block, denoted as mv₀ ^c =( mv₀ ^Ch, mv₀ ^Cv), mv i^C =( mv/^h, mv/') and mv₂ ^c =( mv₂ ^Ch, mv₂ ^Cv), are derived from mv₀ ^N =( mv₀ ^Nh, mv₀ ^Nv), which is the MV at the top-right corner of the affine coded left neighbouring block, mv / =( mv/^h, mv/'), which is the MV at the bottom-right corner of the affine coded left neighbouring block, and mv_A =( mv_A ^h, mv/), which is the auxiliary MV, as

where (x₀, yo) is the coordinate of the top-left corner of the current block and (x’o, y’₀) is the coordinate of the top-right corner of the neighbouirng block.

Alternatively, furthermore, the division operation in (15) could be replaced by shift with or without adding operations.

i. For example, the number K in Eq(15) depends on how the auxiliary position is defined to get the auxiliary MV. In the example disclosed in 2.c.iv, the auxiliary position is (LTNx+w’+Offset), LTNy+(h’»1 )) where Offset=2^K. In an exmaple, K = 3.

e. For example, the affine model inheritance is conducted by deriving the CP MVs of the current block from the top-right MV and bottom-right MV of the affine-coded neighbouring block only if the neighbouring block is in a MxN region that is left ( or above-left, or below-left ) to the MxN region containing the current block.

i. For example, Mx N region is a CTU, e.g. 128x 128 region; ii. For example, Mx N region is the pipeline size, e.g. 64x64 region. f. For example, x₀ = x’o.

i. Alternatively, x₀ = 1 +x’₀.

In one example, the current block only needs to access MVs stored in basic units (e.g. 4x4 block in VVC) in a row above the current block and in a column left to the current block, as shown in Fig. 13. The coordinate of the top-left position of the current block is denoted as (xO, yO). The MVs may be accessed by the current block in the basic unit row (denoted as above required row) above the current block starting at the basic unit with top-left coordinate (xRS, yRS), ending at the basic unit with top-left coordinate (xRE, yRE). Similarly, the MVs may be accessed by the current block in the basic unit column ( denoted as left required column) left to the current block starting at the basic unit with top-left coordinate (xCS, yCS), ending at the basic unit with top-left cooridate (xCE, yCE). The width and height of the current block is deonted as W and H, respectively. Suppose the basic unit size is BxB (e.g. 4x4 in VVC), then yRS=yRE=yO-B and xCS=xCE=xO- B.

a. The range of the above required row and left required column may be constrained.

i. In one example, xRS = xO-nxW-m. n and m are integers, such as n=0, m=0, n = 0, m =1 , n=1 , m=1 , or n=2, m = 1 ;

ii. In one example, xRE = x0+ nxW+m. n and m are integers, such as n = 1 , m =-B, n = 1 , m = B, n=2, m= -B, or n=3, m= -B; iii. In one example, yCS = y0-nxH-m. n and m are integers, such as n=0, m=0, n = 0, m =1 , n=1 , m=1 , or n=2, m = 1 ;

iv. In one example, yCE = y0+ hc H+m. n and m are integers, such as n = 1 , m =-B, n = 1 , m = B, n=2, m= -B, or n=3, m= -B; v. In one example, above required row is not needed by the current block;

vi. In one example, left required column is not needed by the current block;

vii. In one example, selection of xRS, xRE, yCS and yCE may depend on the position of auxiliary block.

(a) In one example, auxiliary block is always covered by the selected above row or left column.

(b) Alternatively, in addition, (xRS, yRS), (xRE, yRE), (xCS, yCS) and (xCE, yCE) shall not overlap with the auxiliary block. viii. In one example, the range of the above required row and left required column depends on the position of the current block.

(a) If the current block is at the top boundary of PxQ region, i.e. when y0%Q==0, where Q may be 128 (CTU region) or 64 (pipeline region)

a. In one example, above required row is not needed by the current block;

b. In one example, xRS = xO;

(b) If the current block is at the left boundary of PxQ region, i.e. when x0%P==0, where P may be 128 (CTU region) or 64 (pipeline region)

a. In one example, left required column is not needed by the current block;

b. In one example, yCS = yO; As an alternative method to bullet 2.d, the three CPMVs of the current block, denoted

mv ₂ ^Cv), are derived from mv o^N =( mv o^Nh, mv o^Nv), which is the MV at the top-right corner of the affine coded left neighbouring block, mv i^W =( mv-_\ ^Nh, mv-_\ ^Nv), which is the MV at the bottom-right corner of the affine coded left neighbouring block, and

block.

Alternatively, furthermore, the division operation in (16) could be replaced by shift with or without adding operations. In bullet l .c.v, the auxiliary MV is stored in one (such as the middle one) of the bottom row of basic unit blocks (e.g. 4x4 block in VVC) of the affine-coded above neighbouring block only if the affine-coded above neighbouring block is coded with the 6-parameter affine model.

a. Alternatively, the auxiliary MV is stored one (such as the middle one) of the bottom row of basic unit blocks (e.g. 4x4 block in VVC) of the affine- coded above neighbouring block no matter whether the affine-coded above neighbouring block is coded with the 4-parameter affine model or the 6-parameter affine model.

In bullet 2.c.v, the auxiliary MV is stored in one (such as the middle one) of the right column of basic unit blocks (e.g. 4x4 block in VVC) of the affine-coded left neighbouring block only if the affine-coded left neighbouring block is coded with the 6-parameter affine model.

a. Alternatively, the auxiliary MV is stored in one (such as the middle one) of the right column of basic unit blocks (e.g. 4x4 block in VVC) of the affine- coded left neighbouring block no matter whether the affine-coded left neighbouring block is coded with the 4-parameter affine model or the 6- parameter affine model.

In one example, the bottom-left basic unit block of the current block always stores the CPMV at the bottom-left corner, no matter the current block employs the 4-parameter model or the 6-parameter model. For an example in Fig. 3, block LB always stores mv2.

In one example, the bottom-right basic unit block of the current block always stores the CPMV at the bottom-right corner, no matter the current block employs the 4-parameter model or the 6-parameter model. For an example in Fig. 3, block RB always stores mv3.

The affine inheritance is conducted in the same way no matter the neighbouring affine coded block employs the 4-parameter model or the 6-parameter model. a. The CPMVs of the current block at the top-left corner, top-right corner and bottom-left corner (e.g. mv_Q ^c, mv i^c and mv₂ ^c in Fig. 4(b)) are derived from the MVs stored in the top-left basic block, top-right basic block and bottom-left basic unit of the neighbouring affine coded block in the way of 6-parameter affine model inheritance.

i. For example, MVs stored in the top-left basic block, top-right basic block and bottom-left basic unit of the neighbouring affine coded block are the CPMV at the top-left corner, the top-right corner and bottom-right corner of the neighbouring affine coded block.

b. The CPMVs of the current block at the top-left corner, top-right corner and bottom-left corner (e.g. mv_Q ^c, mv i^c and mv₂ ^c in Fig. 4(b)) are derived from the MVs stored in the bottom-left basic unit, bottom-right basic unit and an extra basic unit in the bottom row of basic units of the above neighbouring affine coded block in the way defined in bullet 1 .

i. For example, MVs stored in bottom-left basic unit, bottom-right basic unit and an extra basic unit in the bottom row of basic unit of the above neighbouring affine coded block are the CPMV at the bottom-left corner, the CPMV at the bottom-right corner, and the auxiliary MV of the neighbouring affine coded block. c. The CPMVs of the current block at the top-left corner, top-right corner and bottom-left corner (e.g. mv o^c, mv i^c and mv 2 in Fig. 4(b)) are derived from the MVs stored in the top-right basic unit, bottom-right basic unit and an extra basic unit in the right column of basic units of the left neighbouring affine coded block in the way defined in bullet 2.

i. For example, MVs stored in top-right basic unit, bottom-right basic unit and an extra basic unit in the right column of basic units of the left neighbouring affine coded block are the CPMV at the top-right corner, the CPMV at the bottom-right corner, and the auxiliary MV of the neighbouring affine coded block.

d. The inherited affine merge block is always marked as“using 6 parameters” e. When the affine model is inherited from the above neighbouring block, and the width of the above neighbouring block is not greater than 8, then the auxiliary MV is calculated as an average of MVs stored in the bottom-left basic unit and bottom-right basic unit.

i. For example, MVs stored in bottom-left basic unit, bottom-right basic unit of the above neighbouring affine coded block are the CPMV at the bottom-left corner and the CPMV at the bottom-right corner of the above neighbouring affine coded block.

f. When the affine model is inherited from the left neighbouring block, and the height of the left neighbouring block is not greater than 8, then the auxiliary MV is calculated as an average of MVs stored in the top-right basic unit and bottom-right basic unit.

i. For example, MVs stored in top-right basic unit, bottom-right basic unit of the left neighbouring affine coded block are the CPMV at the top-right corner and the CPMV at the bottom-right corner of the left neighbouring affine coded block.

10. In one example, MC for a sub-block is conducted by the MV stored in the sub block.

a. For example, the stored MV is a CPMV;

b. For example, the stored MV is an auxiliary MV.

1 1 . The affine inheritance is conducted in the same way no matter the neighbouring affine coded block employs the 4-parameter model or the 6-parameter model.

12. The auxiliary MV to be stored per coding block may be more than 1 .

a. The usage of auxiliary MVs may be in the same way as described above.

[0081] Fig. 1 1 shows an example of 6-parameter affine inheritance by deriving from MVs stored in the right column of an affine coded left neighbouring block .

[0082] Fig. 12 shows an example of the right column of basic unit blocks(shaded) that can store the auxiliary MV.

[0083] Fig. 13 shows an example of MV storage.

5. Further Embodiment

[0084] This section discloses an example of embodiment of the proposed invention.

It should be noted that it is only one of the all possible embodiments of the proposed methods and should not be understood in a narrow way.

Normalize^, b) is define as in Eq (7). [0085] Input:

• The coordinate of top-left corner of the current block noted as (posCurX, posCurY);

• The coordinate of top-left corner of the neighbouring block noted as (posLTX, posLTY);

• The coordinate of top-right corner of the neighbouring block noted as (posRTX, posRTY);

• The coordinate of bottom-left corner of the neighbouring block noted as (posLBX, posLBY);

• The coordinate of bottom-right corner of the neighbouring block noted as (posRBX, posRBY);

• The width and height of the current block noted as W and H;

• The width and height of the neigbhouring block noted as W’ and H’;

• The MV at top-left corner of the neighbouring block noted as (mvLTX, mvLTY);

• The MV at top-right corner of the neighbouring block noted as (mvRTX, mvRTY);

• The MV at bottom-left corner of the neighbouring block noted as (mvLBX, mvLBY);

• The MV at bottom-right corner of the neighbouring block noted as (mvRBX, mvRBY);

• A constant number: shift, which can be any positive integer such as 7 or 8.

[0086] Output:

• The MV at top-left corner of the current block noted as (MV0X, MV0Y);

• The MV at top-right corner of the current block noted as (MV1 X, MV1 Y);

• The MV at bottom-right corner of the current block noted as (MV2X, MV2Y);

[0087] Procedure of affine model inheritance:

If posRBY is equal to (posCurY-1 ) { // Above neighbouring block

iDMvHorX - (mvRBX - mvLBX) « (shift - log2(W’))

iDMvHorY - (mvRBY - mvLBY) « (shift - log2(W’))

iDMvVerX - -iDMvHorY;

iDMvVerY - iDMvHorX; if the neighbouring block applies the 6-parameter affine model and W’ > 8{ AuxiliaryX = posLBx + (W’ » 1 );

AuxiliaryY = posLBy;

(mvAuxiliaryX, mvAuxiliaryY) is set to be the MV stored in the basic unit block containing (AuxiliaryX, AuxiliaryY);

mvMidX = Normalize( mvRBX + mvLBX, 1 );

mvMidY = Normalize^ mvRBY + mvLBY, 1 ); iDMvVerX = (mvAuxiliaryX - mvMidX) « (shift - 3);

iDMvVerY = (mvAuxiliaryY - mvMidY) « (shift - 3);

}

iMvScaleHor = mvLBX « shift;

iMvScaleVer = mvLBY « shift; posNeiX = posLBX;

posNeiY = posLBY + 1 ;

}

else if posRBX is equal to (posCurX -1 ) {//Left neighbouring block

iDMvHorX - (mvRBY- mvRTY) « (shift - log2(H’))

iDMvHorY - -(mvRBX - mvRTX) « (shift - log2(H’))

iDMvVerX - -iDMvHorY;

iDMvVerY - iDMvHorX; if the neighbouring block applies the 6-parameter affine model and H’ > 8 { AuxiliaryX = posRTX;

AuxiliaryY = posRTY + (H’»1 );

(mvAuxiliaryX, mvAuxiliaryY) is set to be the MV stored in the basic unit block containing (AuxiliaryX, AuxiliaryY);

mvMidX = Normalize( mvRBX + mvRTX, 1 );

mvMidY = Normalize^ mvRBY + mvRTY, 1 ); iDMvHorX = (mvAuxiliaryX - mvMidX) « (shift - 3);

iDMvHorY = (mvAuxiliaryY - mvMidY) « (shift - 3); iMvScaleHor = mvRTX « shift;

iMvScaleVer = mvRTY « shift;

posNeiX = posRTX+1 ;

posNeiY = posRTY;

}

else{

Return“Input is invalid!”

}

}

horTmpO = iMvScaleHor + iDMvHorX ^* (posCurX - posNeiX) + iDMvVerX ^* (posCurY - posNeiY);

verTmpO = iMvScaleVer + iDMvHorY ^* (posCurX - posNeiX) + iDMvVerY ^* (posCurY - posNeiY);

MVOX = Normalize ( horTmpO, shift );

MVOY = Normalize ( verTmpO, shift ); horTmpl = iMvScaleHor + iDMvHorX ^* (posCurX + W - posNeiX) + iDMvVerX ^* (posCurY - posNeiY);

verTmpl = iMvScaleVer + DMvHorY ^* (posCurX + W - posNeiX) + iDMvVerY ^* (posCurY - posNeiY);

MV1 X = Normalize ( horTmpl , shift );

MV1 Y = Normalize ( verTmpl , shift );

if the neighbouring block applies the 6-parameter affine model{

The current block also applies the 6-parameter affine model;

horTmp2 = iMvScaleHor + iDMvHorX ^* (posCurX - posNeiX) + iDMvVerX ^* (posCurY+H - posNeiY);

verTmp2 = iMvScaleVer + DMvHorY ^* (posCurX - posNeiX) + iDMvVerY ^* (posCurY+H- posNeiY);

MV2X = Normalize ( horTmp2, shift );

MV2Y = Normalize ( verTmp2, shift );

}

[0088] FIG. 14 is a block diagram illustrating an example of the architecture for a computer system or other control device 2600 that can be utilized to implement various portions of the presently disclosed technology. In FIG. 14, the computer system 2600 includes one or more processors 2605 and memory 2610 connected via an interconnect 2625. The interconnect 2625 may represent any one or more separate physical buses, point to point connections, or both, connected by appropriate bridges, adapters, or controllers. The interconnect 2625, therefore, may include, for example, a system bus, a Peripheral Component Interconnect (PCI) bus, a HyperTransport or industry standard architecture (ISA) bus, a small computer system interface (SCSI) bus, a universal serial bus (USB), I IC (I2C) bus, or an Institute of Electrical and Electronics Engineers (IEEE) standard 674 bus, sometimes referred to as“Firewire.”

[0089] The processor(s) 2605 may include central processing units (CPUs) to control the overall operation of, for example, the host computer. In certain embodiments, the processor(s) 2605 accomplish this by executing software or firmware stored in memory 2610. The processor(s) 2605 may be, or may include, one or more programmable general-purpose or special-purpose microprocessors, digital signal processors (DSPs), programmable controllers, application specific integrated circuits (ASICs), programmable logic devices (PLDs), or the like, or a combination of such devices.

[0090] The memory 2610 can be or include the main memory of the computer system. The memory 261 0 represents any suitable form of random access memory (RAM), read-only memory (ROM), flash memory, or the like, or a combination of such devices. In use, the memory 2610 may contain, among other things, a set of machine instructions which, when executed by processor 2605, causes the processor 2605 to perform operations to implement embodiments of the presently disclosed technology.

[0091] Also connected to the processor(s) 2605 through the interconnect 2625 is a (optional) network adapter 2615. The network adapter 2615 provides the computer system 2600 with the ability to communicate with remote devices, such as the storage clients, and/or other storage servers, and may be, for example, an Ethernet adapter or Fiber Channel adapter.

[0092] FIG. 15 shows a block diagram of an example embodiment of a device 2700 that can be utilized to implement various portions of the presently disclosed technology. The mobile device 2700 can be a laptop, a smartphone, a tablet, a camcorder, or other types of devices that are capable of processing videos. The mobile device 2700 includes a processor or controller 2701 to process data, and memory 2702 in

communication with the processor 2701 to store and/or buffer data. For example, the processor 2701 can include a central processing unit (CPU) or a microcontroller unit (MCU). In some implementations, the processor 2701 can include a field- programmable gate-array (FPGA). In some implementations, the mobile device 2700 includes or is in communication with a graphics processing unit (GPU), video

processing unit (VPU) and/or wireless communications unit for various visual and/or communications data processing functions of the smartphone device. For example, the memory 2702 can include and store processor-executable code, which when executed by the processor 2701 , configures the mobile device 2700 to perform various operations, e.g., such as receiving information, commands, and/or data, processing information and data, and transmitting or providing processed information/data to another device, such as an actuator or external display. To support various functions of the mobile device 2700, the memory 2702 can store information and data, such as instructions, software, values, images, and other data processed or referenced by the processor 2701 . For example, various types of Random Access Memory (RAM) devices, Read Only Memory (ROM) devices, Flash Memory devices, and other suitable storage media can be used to implement storage functions of the memory 2702. In some implementations, the mobile device 2700 includes an input/output (I/O) unit 2703 to interface the processor 2701 and/or memory 2702 to other modules, units or devices. For example, the I/O unit 2703 can interface the processor 2701 and memory 2702 with to utilize various types of wireless interfaces compatible with typical data communication standards, e.g., such as between the one or more computers in the cloud and the user device. In some implementations, the mobile device 2700 can interface with other devices using a wired connection via the I/O unit 2703. The mobile device 2700 can also interface with other external interfaces, such as data storage, and/or visual or audio display devices 2704, to retrieve and transfer data and information that can be processed by the processor, stored in the memory, or exhibited on an output unit of a display device 2704 or an external device. For example, the display device 2704 can display a video frame modified based on the MVPs in accordance with the disclosed technology.

[0093] FIG. 16 is a flowchart for a method 1600 of video or image processing. The method 1600 includes determining(1602) an affine model of a neighboring block adjacent to a current block; deriving(1604) control point motion vectors of the current block from the neighboring block at least based on one of the affine model of the neighboring block and a location of the neighboring block relative to the current block; and performing(1606) a video processing between the current block and a bitstream representation of the current block based on the control point motion vectors.

[0094] Various embodiments and techniques disclosed in the present document can be described in the following listing of examples..

[0095] 1 . A method of video processing, comprising:

determining an affine model of a neighboring block adjacent to a current block; deriving control point motion vectors of the current block from the neighboring block at least based on one of the affine model of the neighboring block and a location of the neighboring block relative to the current block; and

performing a video processing between the current block and a bitstream representation of the current block based on the control point motion vectors.

[0096] 2. The method of example 1 , wherein the affine model for the neighboring block is a 6-parameter affine model.

[0097] 3. The method of example 2, comprising:

deriving control point (CP) motion vectors (MV) of the current block by using two MVs in the neighboring block and an auxiliary MV derived from the neighboring block.

[0098] 4. The method of example 3, wherein the auxiliary MV is derived, with an auxiliary position, from the affine model of the neighboring block.

[0099] 5. The method of example 4, wherein the auxiliary position is predefined or depends on dimensions of the neighboring block.

[00100] 6. The method of example 5, wherein the auxiliary position is signaled in at least one of video parameter set(VSP), sequence parameter set(SPS), picture parameter set(PPS), slice header, coding tree unit(CTU) and coding unit(CU).

[00101] 7. The method of example 4, wherein the two MVs in the neighboring block comprise a MV at a bottom-left corner and a MV at a bottom-right corner of the neighboring block if the neighboring block is located above the current block.

[00102] 8. The method of example 4, wherein the two MVs in the neighboring block comprise a MV at a top-right corner and a MV at a bottom-right corner of the neighboring block if the neighboring block is located left to the current block.

[00103] 9. The method of example 7, wherein the neighboring block is coded with the

6-parameter affine model and has a width larger than a first threshold.

[00104] 10. The method of example 9, wherein the first threshold is equal to 8.

[00105] 1 1 . The method of example 8, wherein the neighboring block is coded with the 6-parameter affine model and has a height larger than a second threshold.

[00106] 12. The method of example 1 1 , wherein the second threshold is equal to 8.

[00107] 13. The method of example 7, wherein the auxiliary position is (LTNx

+(w’»1 ), LTNy + h’+ Offset), wherein (LTNx,LTNy) represents coordinates of a top-left corner of the neighboring block, w’ represents a width of the neighboring block, h’ represents a height of the neighboring block, and Offset is an integer.

[00108] 14. The method of example 8, wherein the auxiliary position is (LTNx

+w’+Offset), LTNy +( h’»1 )), wherein (LTNx, LTNy) represents coordinates of a top-left corner of the neighboring block, w’ represents a width of the neighboring block, h’ represents a height of the neighboring block, and Offset is an integer.

[00109] 15. The method of example 13 or 14, wherein Offset=2^K or Offset = -2^K, and K is 1 , 2, 3, 4, or 5.

[00110] 16. The method of example 7, wherein the auxiliary MV is stored in one of basic unit blocks of a bottom row of the neighboring block, the basic unit blocks of the bottom row of the neighboring block being represented as B(0), B(1 ), ..., B(M-1 ) from left to right.

[00111] 17. The method of example 8, wherein the auxiliary MV is stored in one of basic unit blocks of a rightmost column of the neighboring block, the basic unit blocks of the rightmost column of the neighboring block being represented as B(0), B(1 ), ..., B(M- 1 ) from top to bottom.

[00112] 18. The method of example 16 or 17, wherein each of the basic unit blocks has a size of 4x4.

[00113] 19. The method of example 16 or 17, wherein the auxiliary MV is stored in one of the basic unit blocks B(M/2), B(M/2+1 ) and B(M/2-1 ).

[00114] 20. The method of any one of examples 16-19, wherein the neighboring block is coded with a 6-parameter affine model or a 4-parameter affine model.

[00115] 21 . The method of example 16 or 17, wherein the auxiliary MV is not stored in any of the basic unit blocks B(0) and B(M-1 ).

[00116] 22. The method of any one of examples 16-21 , wherein the stored auxiliary

MV is further used for motion prediction or merge for at least one of succeeding prediction unit (PU), succeeding coding unit(CU) and succeeding picture.

[00117] 23. The method of any one of examples 16-22, wherein the stored auxiliary

MV is further used for a filtering process for the current block.

[00118] 24. The method of example 7, wherein the auxiliary MV is stored in an additional buffer rather than any of basic unit blocks of a bottom row of the neighboring block.

[00119] 25. The method of example 8, wherein the auxiliary MV is stored in an additional buffer rather than in any of basic unit blocks of a rightmost column of the neighboring block. [00120] 26. The method of example 24 or 25, wherein the stored auxiliary MV is neither used for motion prediction or merge for at least one of succeeding prediction unit (PU), succeeding coding unit(CU) and succeeding picture, nor for filtering process for the current block.

[00121] 27. The method of example 14, wherein the auxiliary MV is derived from the affine model of the neighboring block as follows:

wherein {mv^h ₀, mv^v ₀) is a motion vector of a top-left corner of the neighboring block, and (miA, mv^vi) is a motion vector of a top-right corner thereof and (mi/2, mv^v ₂) is a motion vector of a bottom-left corner thereof, (x, y) represents a coordinate of the auxiliary position.

[00122] 28. The method of example 27, wherein the auxiliary MV is stored in an auxiliary block and is not used for motion compensation for the auxiliary block.

[00123] 29. The method of example 7, wherein the CPMVs vectors(MV) of the current block are derived as follows:

where mv₀ ^c representing the CPMV at the top-left corner of the current block, mi/i^c representing the CPMV at the top-right corner of the current block, a

, mv₂ ^Cv ), representing the CPMV at the bottom-left corner of the current block, mv₀ ^N =( mv₀ ^Nh, mv₀ ^Nv), representing the MV at the bottom- left corner of the neighbouring block,

representing the MV at the bottom-right corner of the neighbouring block, and mv_A ={ mv_A ^h, mv ), representing the auxiliary MV, (x₀, y₀) is the coordinate of the top-left corner of the current block and (x’₀, y’o) is the coordinate of the bottom-left corner of the neighboring block.

[00124] 30. The method of example 8, wherein the CPMVs vectors(MV) of the current block are derived as follows:

where mv₀ ^c representing the CPMV at the top-left corner of the current block, mi/i^c representing the CPMV at the top-right corner of the current block, a

, mv₂ ^Cv ), representing the CPMV at the bottom-left corner of the current block, mv₀ ^N =( mv₀ ^Nh, mv₀ ^Nv), representing the MV at the top-right corner of the neighbouring block,

representing the MV at the bottom-right corner of the neighbouring block, and mv_A ={ mv_A ^h, mv ), representing the auxiliary MV, (x₀, y₀) is the coordinate of the top-left corner of the current block and (x’₀, y’o) is the coordinate of the top-right corner of the neighboring block.

[00125] 31 . The method of example 8, wherein the CPMVs vectors(MV) of the current block are derived as follows:

where mv₀ ^c representing the CPMV at the top-left corner of the current block, mi/i^c representing the CPMV at the top-right corner of the current block, a

, mv₂ ^Cv ), representing the CPMV at the bottom-left corner of the current block, mv₀ ^N =( mv₀ ^Nh, mv₀ ^Nv), representing the MV at the top-right corner of the neighbouring block,

^Nv), representing the MV at the bottom-right corner of the neighbouring block, and mv_A ={ mv_A ^h, mv ), representing the auxiliary MV, (x₀, y₀) is the coordinate of the top-left corner of the current block and (x’₀, y’o) is the coordinate of the top-right corner of the neighboring block.

[00126] 32. The method of any one of examples 29-31 , wherein the division operation in any of equation (14)-(16) can be replaced by right shift with or without adding an offset before the shift.

[00127] 33. The method of example 29, wherein K in equation (14) depends on how the auxiliary position is defined to get the auxiliary MV.

[00128] 34. The method of example 33, wherein the auxiliary position is

(LTNx+(w’»1 ), LTNy+h’+Offset) where Offset=2^K.

[00129] 35. The method of example 30, wherein K in equation (15) depends on how the auxiliary position is defined to get the auxiliary MV.

[00130] 36. The method of example 35, wherein the auxiliary position is (LTNx

+w’+Offset, LTNy +( h’»1 )) where Offset=2^K.

[00131] 37. The method of example 34 or 36, wherein K = 3.

[00132] 38. The method of example 7, wherein the neighboring block is in a MxN region that is located above, above-right, or above-left to a MxN region containing the current block.

[00133] 39. The method of example 8, wherein the neighboring block is in a MxN region that is located left, above-left, or below-left to a MxN region containing the current block.

[00134] 40. The method of example 38 or 39, wherein the Mx N region has a size of coding tree unit(CTU) or a pipeline size.

[00135] 41 . The method of example 40, wherein the MxN region has a size of

128x128 or 64x64.

[00136] 42. The method of example 7, wherein y₀ = y’o or y₀ = 1 +y’o, (xo, yo) representing the coordinate of the top-left corner of the current block and (x’₀, y’₀) representing the coordinate of the bottom-left corner of the neighboring block.

[00137] 43. The method of example 8, wherein x₀ = x’o or x₀ = 1 +x’o, (x₀, yo) representing the coordinate of the top-left corner of the current block and (x’₀, y’₀) representing the coordinate of the bottom-left corner of the neighboring block.

[00138] 44. The method of example 2, comprising:

deriving control point(CP) motion vectors(MV) of the current block by MVs in the neighboring block in a unified way, wherein the neighboring block is coded with a 4- parameter affine model or a 6-parameter affine model.

[00139] 45. The method of example 44, wherein the CPMVs of the current block at top-left, top-right and bottom-left corners of the current block respectively are derived from the MVs stored respectively in a top-left, top-right and bottom-left basic unit blocks of the neighboring block in a way of 6-parameter affine model inheritance.

[00140] 46. The method of example 45, wherein the MVs stored in the top-left basic unit block, top-right basic unit block and bottom-left basic unit block of the neighbouring block are the CPMVs at the top-left corner, the top-right corner and bottom-right corner of the neighbouring block respectively.

[00141] 47. The method of example 44, wherein the CPMVs of the current block at top-left, top-right and bottom-left corners of the current block respectively are derived from the MVs stored respectively in a bottom-left, bottom-right and extra basic unit blocks in a bottom row of the neighboring block if the neighboring block is located above the current block.

[00142] 48. The method of example 47, wherein the MVs stored in the bottom-left basic unit block, bottom-right basic unit block and the extra basic unit block of the neighbouring block are the CPMVs at the bottom-left and bottom-right corners of the neighbouring block and the auxiliary MV of the neighbouring block respectively.

[00143] 49. The method of example 44, wherein the CPMVs of the current block at top-left, top-right and bottom-left corners of the current block respectively are derived from the MVs stored respectively in a top-right, bottom-right and extra basic unit blocks in a rightmost column of the neighboring block if the neighboring block is located left to the current block.

[00144] 50. The method of example 49, wherein the MVs stored in the top-right basic unit block, bottom-right basic unit block and the extra basic unit block of the

neighbouring block are the CPMVs at the top-right and bottom-right corners of the neighbouring block and the auxiliary MV of the neighbouring block respectively.

[00145] 51 . The method of any one of examples 45-50, wherein the current block is indicated as an inherited block using a 6-parameter affine model.

[00146] 52. The method of any one of examples 47-48, wherein a width of the neighboring block is not greater than 8, and the auxiliary MV is calculated as an average of MVs stored in the bottom-left basic unit block and bottom-right basic unit block of the neighboring block.

[00147] 53. The method of any one of examples 49-50, wherein a height of the neighboring block is not greater than 8, and the auxiliary MV is calculated as an average of MVs stored in the top-right basic unit block and bottom-right basic unit block of the neighboring block.

[00148] 54. The method of example 48 or 50, wherein more than one auxiliary MV is stored for the current block. [00149] 55. The method of any one of examples 1 -54, wherein the video processing comprises at least one of encoding the video block into the bitstream representation of the video block and decoding the video block from the bitstream representation of the video block.

[00150] 56. A video processing apparatus comprising a processor configured to implement the method of any one of examples 1 to 55.

[00151] 57. A computer program product stored on a non-transitory computer readable media, the computer program product including program code for carrying out the method in any one of examples 1 to 55.

[00152] The disclosed and other 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.

[00153] 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.

[00154] 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).

[00155] 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., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto optical disks; and CD ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

[00156] While this patent document contains many specifics, these should not be construed as limitations on the scope of any invention or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular inventions. 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.

[00157] 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.

[00158] 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.

Claims

CLAIMS What is claimed is:

1 . A method of video processing, comprising:

determining an affine model of a neighboring block adjacent to a current block; deriving control point motion vectors of the current block from the neighboring block at least based on one of the affine model of the neighboring block and a location of the neighboring block relative to the current block; and

performing a video processing between the current block and a bitstream representation of the current block based on the control point motion vectors.

2. The method of claim 1 , wherein the affine model for the neighboring block is a 6- parameter affine model.

3. The method of claim 2, comprising:

deriving control point (CP) motion vectors (MV) of the current block by using two MVs in the neighboring block and an auxiliary MV derived from the neighboring block.

4. The method of claim 3, wherein the auxiliary MV is derived, with an auxiliary position, from the affine model of the neighboring block.

5. The method of claim 4, wherein the auxiliary position is predefined or depends on dimensions of the neighboring block.

6. The method of claim 5, wherein the auxiliary position is signaled in at least one of video parameter set(VSP), sequence parameter set(SPS), picture parameter set(PPS), slice header, coding tree unit(CTU) and coding unit(CU).

7. The method of claim 4, wherein the two MVs in the neighboring block comprise a MV at a bottom-left corner and a MV at a bottom-right corner of the neighboring block if the neighboring block is located above the current block.

8. The method of claim 4, wherein the two MVs in the neighboring block comprise a MV at a top-right corner and a MV at a bottom-right corner of the neighboring block if the neighboring block is located left to the current block.

9. The method of claim 7, wherein the neighboring block is coded with the 6-parameter affine model and has a width larger than a first threshold.

10. The method of claim 9, wherein the first threshold is equal to 8.

1 1 . The method of claim 8, wherein the neighboring block is coded with the 6-parameter affine model and has a height larger than a second threshold.

12. The method of claim 1 1 , wherein the second threshold is equal to 8.

13. The method of claim 7, wherein the auxiliary position is (LTNx +(w’»1 ), LTNy + h’+ Offset), wherein (LTNx, LTNy) represents coordinates of a top-left corner of the neighboring block, w’ represents a width of the neighboring block, h’ represents a height of the neighboring block, and Offset is an integer.

14. The method of claim 8, wherein the auxiliary position is (LTNx +w’+Offset), LTNy +( h’»1 )), wherein (LTNx, LTNy) represents coordinates of a top-left corner of the neighboring block, w’ represents a width of the neighboring block, h’ represents a height of the neighboring block, and Offset is an integer.

15. The method of claim 13 or 14, wherein Offset=2^K or Offset = -2^K, and K is 1 , 2, 3, 4, or 5.

16. The method of claim 7, wherein the auxiliary MV is stored in one of basic unit blocks of a bottom row of the neighboring block, the basic unit blocks of the bottom row of the neighboring block being represented as B(0), B(1 ),..., B(M-1 ) from left to right.

17. The method of claim 8, wherein the auxiliary MV is stored in one of basic unit blocks of a rightmost column of the neighboring block, the basic unit blocks of the rightmost column of the neighboring block being represented as B(0), B(1 ), ..., B(M-1 ) from top to bottom.

18. The method of claim 16 or 17, wherein each of the basic unit blocks has a size of 4x4.

19. The method of claim 16 or 17, wherein the auxiliary MV is stored in one of the basic unit blocks B(M/2), B(M/2+1 ) and B(M/2-1 ).

20. The method of any one of claims 16-19, wherein the neighboring block is coded with a 6-parameter affine model or a 4-parameter affine model.

21 . The method of claim 16 or 17, wherein the auxiliary MV is not stored in any of the basic unit blocks B(0) and B(M-1 ).

22. The method of any one of claims 16-21 , wherein the stored auxiliary MV is further used for motion prediction or merge for at least one of succeeding prediction unit (PU), succeeding coding unit(CU) and succeeding picture.

23. The method of any one of claims 16-22, wherein the stored auxiliary MV is further used for a filtering process for the current block.

24. The method of claim 7, wherein the auxiliary MV is stored in an additional buffer rather than any of basic unit blocks of a bottom row of the neighboring block.

25. The method of claim 8, wherein the auxiliary MV is stored in an additional buffer rather than in any of basic unit blocks of a rightmost column of the neighboring block.

26. The method of claim 24 or 25, wherein the stored auxiliary MV is neither used for motion prediction or merge for at least one of succeeding prediction unit (PU), succeeding coding unit(CU) and succeeding picture, nor for filtering process for the current block.

27. The method of claim 14, wherein the auxiliary MV is derived from the affine model of the neighboring block as follows:

wherein (mi/o, mv^v ₀) is a motion vector of a top-left corner of the neighboring block, and (miA, mv^v ₁) is a motion vector of a top-right corner thereof and

mv^v ₂) is a motion vector of a bottom-left corner thereof, (x, y) represents a coordinate of the auxiliary position.

28. The method of claim 27, wherein the auxiliary MV is stored in an auxiliary block and is not used for motion compensation for the auxiliary block.

29. The method of claim 7, wherein the CPMVs vectors(MV) of the current block are derived as follows:

where mv₀ ^c =( mv₀ ^Ch, mv₀ ^Cv), representing the CPMV at the top-left corner of the current block,

^Cv), representing the CPMV at the top-right corner of the current block, and mv₂ ^c =( mv₂ ^Ch, mv₂ ^Cv), representing the CPMV at the bottom-left corner of the current block, m v_Q ^N =( mv₀ ^Nh, mv₀ ^Nv), representing the MV at the bottom-left corner of the neighbouring block,

, representing the MV at the bottom-right corner of the neighbouring block, and mv_A =( mv_A ^h, mv_A ), representing the auxiliary MV, (x₀, y₀) is the coordinate of the top-left corner of the current block and (x’o, y’o) is the coordinate of the bottom-left corner of the neighboring block.

30. The method of claim 8, wherein the CPMVs vectors(MV) of the current block are derived as follows:

where mv₀ ^c =( mv₀ ^Ch, mv₀ ^Cv), representing the CPMV at the top-left corner of the current block, mv-_\ ^c =( mv-_\ ^Ch, mv-_\ ^Cv), representing the CPMV at the top-right corner of the current block, and mv₂ ^c =( mv₂ ^Ch, mv₂ ^Cv), representing the CPMV at the bottom-left corner of the current block, m v_Q ^N =( mvo^Nh, mvo^Nv), representing the MV at the top-right corner of the neighbouring block,

, representing the MV at the bottom-right corner of the neighbouring block, and mv_A =( mv_A ^h, mv_A ^v), representing the auxiliary MV, (x₀, yo) is the coordinate of the top-left corner of the current block and (x’₀, y’₀) is the coordinate of the top-right corner of the neighboring block.

31 . The method of claim 8, wherein the CPMVs vectors(MV) of the current block are derived as follows:

where mv₀ ^c =( mv₀ ^Ch, mv₀ ^Cv), representing the CPMV at the top-left corner of the current block,

^Cv), representing the CPMV at the top-right corner of the current block, and mv₂ ^c =( mv₂ ^Ch, mv₂ ^Cv), representing the CPMV at the bottom-left corner of the current block, m v_Q ^N =( mv₀ ^Nh, mv₀ ^Nv), representing the MV at the top-right corner of the neighbouring block,

, representing the MV at the bottom-right corner of the neighbouring block, and mv_A =( mv_A ^h, mv_A ^v), representing the auxiliary MV, (x₀, y₀) is the coordinate of the top-left corner of the current block and (x’₀, y’₀) is the coordinate of the top-right corner of the neighboring block.

32. The method of any one of claims 29-31 , wherein the division operation in any of equation (14)-(16) can be replaced by right shift with or without adding an offset before the shift.

33. The method of claim 29, wherein K in equation (14) depends on how the auxiliary position is defined to get the auxiliary MV.

34. The method of claim 33, wherein the auxiliary position is (LTNx+(w’»1 ),

LTNy+h’+Offset) where Offset=2^K.

35. The method of claim 30, wherein K in equation (15) depends on how the auxiliary position is defined to get the auxiliary MV.

36. The method of claim 35, wherein the auxiliary position is (LTNx +w’+Offset, LTNy +( h’»1 )) where Offset=2^K.

37. The method of claim 34 or 36, wherein K = 3.

38. The method of claim 7, wherein the neighboring block is in a MxN region that is located above, above-right, or above-left to a MxN region containing the current block.

39. The method of claim 8, wherein the neighboring block is in a MxN region that is located left, above-left, or below-left to a MxN region containing the current block.

40. The method of claim 38 or 39, wherein the MxN region has a size of coding tree unit(CTU) or a pipeline size.

41 . The method of claim 40, wherein the MxN region has a size of 128x 128 or 64x64.

42. The method of claim 7, wherein y₀ = yo or y₀ = 1 +y’o, (xo, yo) representing the coordinate of the top-left corner of the current block and (x’₀, y’₀) representing the coordinate of the bottom-left corner of the neighboring block.

43. The method of claim 8, wherein x₀ = x’o or x₀ = 1 +x’o, (x₀, yo) representing the coordinate of the top-left corner of the current block and (x’o, y’o) representing the coordinate of the bottom-left corner of the neighboring block.

44. The method of claim 2, comprising: deriving control point(CP) motion vectors(MV) of the current block by MVs in the neighboring block in a unified way, wherein the neighboring block is coded with a 4- parameter affine model or a 6-parameter affine model.

45. The method of claim 44, wherein the CPMVs of the current block at top-left, top-right and bottom-left corners of the current block respectively are derived from the MVs stored respectively in a top-left, top-right and bottom-left basic unit blocks of the neighboring block in a way of 6-parameter affine model inheritance.

46. The method of claim 45, wherein the MVs stored in the top-left basic unit block, top- right basic unit block and bottom-left basic unit block of the neighbouring block are the CPMVs at the top-left corner, the top-right corner and bottom-right corner of the neighbouring block respectively.

47. The method of claim 44, wherein the CPMVs of the current block at top-left, top-right and bottom-left corners of the current block respectively are derived from the MVs stored respectively in a bottom-left, bottom-right and extra basic unit blocks in a bottom row of the neighboring block if the neighboring block is located above the current block.

48. The method of claim 47, wherein the MVs stored in the bottom-left basic unit block, bottom-right basic unit block and the extra basic unit block of the neighbouring block are the CPMVs at the bottom-left and bottom-right corners of the neighbouring block and the auxiliary MV of the neighbouring block respectively.

49. The method of claim 44, wherein the CPMVs of the current block at top-left, top-right and bottom-left corners of the current block respectively are derived from the MVs stored respectively in a top-right, bottom-right and extra basic unit blocks in a rightmost column of the neighboring block if the neighboring block is located left to the current block.

50. The method of claim 49, wherein the MVs stored in the top-right basic unit block, bottom-right basic unit block and the extra basic unit block of the neighbouring block are the CPMVs at the top-right and bottom-right corners of the neighbouring block and the auxiliary MV of the neighbouring block respectively.

51 . The method of any one of claims 45-50, wherein the current block is indicated as an inherited block using a 6-parameter affine model.

52. The method of any one of claims 47-48, wherein a width of the neighboring block is not greater than 8, and the auxiliary MV is calculated as an average of MVs stored in the bottom-left basic unit block and bottom-right basic unit block of the neighboring block.

53. The method of any one of claims 49-50, wherein a height of the neighboring block is not greater than 8, and the auxiliary MV is calculated as an average of MVs stored in the top-right basic unit block and bottom-right basic unit block of the neighboring block.

54. The method of claim 48 or 50, wherein more than one auxiliary MV is stored for the current block.

55. The method of any one of claims 1 -54, wherein the video processing comprises at least one of encoding the video block into the bitstream representation of the video block and decoding the video block from the bitstream representation of the video block.

56. A video processing apparatus comprising a processor configured to implement the method of any one of claims 1 to 55.

57. A computer program product stored on a non-transitory computer readable media, the computer program product including program code for carrying out the method in any one of claims 1 to 55.