98 results about "Affine motion" patented technology

A method includes determining, for a conversion between a video block of a video and a bitstream of the video, a size of prediction block corresponding to the video block according to a rule. The method also includes performing the conversion based on the determining. The rule specifies that a first size of the prediction block is determined responsive to whether a prediction refinement using optical flow technique is used for coding the video block. The video block has a second size and is coded using an affine merge mode or an affine advanced motion vector prediction mode.

A method for coding a video implemented in an encoder or a decoder including the enhanced interpolation filter, EIF, for motion compensation, the method comprising: i) determining control point motion vectors, CPMVs, for a block according to affine inter-prediction, the block being an affine block or a sub-block of the affine block; ii) for a predefined sub-block size determining a reference area for a sub-block with the predefined sub-block size according to values of the CPMVs; iii) comparing the determined reference area with a predefined threshold; iv) applying EIF for motion compensation, comprising deriving the pixel-based motion vector field for the block; wherein if the determined reference area is larger than the threshold, deriving the pixel-based motion vector field for the block further comprises motion vector clipping, wherein motion vector clipping range is determined based on motion model of the block and the size of the block.

A video bitstream is received. The video bitstream includes coded information of a current block in a current picture and of a plurality of reference pictures of the current block in a reference list. The coded information indicates that the current block is coded in an affine mode. A first control point motion vector (CPMV) of a first control point of the current block is determined. The first CPMV is associated with a sum of a plurality of intermediate vectors. The plurality of intermediate vectors includes an initial CPMV and an intermediate motion vector (MV). The initial CPMV is between the current picture and an initial reference picture of the plurality of reference pictures. The intermediate MV is between two respective reference pictures of the plurality of reference pictures. The current block is reconstructed based on the first CPMV of the first control point of the current block.

The present invention provides an affine motion estimation method for a dynamic point cloud. The method comprises the following steps: (1) point cloud preorder motion analysis: reading a point cloud sequence to be processed, estimating an affine motion field of the current point cloud starting from a third frame, and performing, on a point cloud having undergone preorder decoding, inter-frame geometric motion analysis to obtain motion prior information; (2) point cloud subset division based on the motion prior information; and (3) affine motion estimation of point cloud subsets: establishing a geometric matching relationship between a reference point cloud subset and the current frame, obtaining an affine transformation matrix between a reference frame subset and the current frame on the basis of singular value decomposition, and iterating all the point cloud subsets to complete affine motion estimation from reference frames to the current frame. The method of the present invention further improves the compression performance of a dynamic point cloud.

A video bitstream is received. The video bitstream includes coded information of a current block in a current picture and of a plurality of reference pictures of the current block in a reference list. The coded information indicates that the current block is coded in an affine mode. A first control point motion vector (CPMV) of a first control point of the current block is determined. The first CPMV is associated with a sum of a plurality of intermediate vectors. The plurality of intermediate vectors includes an initial CPMV and an intermediate motion vector (MV). The initial CPMV is between the current picture and an initial reference picture of the plurality of reference pictures. The intermediate MV is between two respective reference pictures of the plurality of reference pictures. The current block is reconstructed based on the first CPMV of the first control point of the current block.

Systems and methods are described for video coding using affine motion models with adaptive precision. In an example, a block of video is encoded in a bitstream using an affine motion model, where the affine motion model is characterized by at least two motion vectors. A precision is selected for each of the motion vectors, and the selected precisions are signaled in the bitstream. In some embodiments, the precisions are signaled by including in the bitstream information that identifies one of a plurality of elements in a selected predetermined precision set. The identified element indicates the precision of each of the motion vectors that characterize the affine motion model. In some embodiments, the precision set to be used is signaled expressly in the bitstream; in other embodiments, the precision set may be inferred, e.g., from the block size, block shape or temporal layer.

Devices, systems, and methods for digital video coding, which includes deriving regression-based motion vector field (RMVF)-based motion vector information, are described. An exemplary method for video processing includes deriving, from at least one set of neighboring blocks in a RMVF scheme, one or more control point motion vector predictors (CPMVPs) of an affine model for a current video block. The method also includes updating a motion candidate list for the current video block based on the one or more CPMVPs. The one or more CPMVPs are associated with a specific affine motion mode. The method further includes performing a conversion for the current video block based on the motion candidate list.

The present disclosure relates to a method for deriving constructed affine merge candidates. The method includes acquiring one or more control point sets from a decoder. The decoder determines whether a reference index of each control point for the control point set index within the control point set associated with a reference index pointing into a reference picture in a first reference picture list is greater than or equal to zero and each is equal to each other. The decoder also determines whether a reference index of each control point for the control point set index within the control point set associated with a reference index pointing into a reference picture in a second reference picture list is greater than or equal to zero and each is equal to each other. The decoder determines that an affine motion model is available based on the determination result.

The present application relates to a method of decoding a video picture, decoding temporal bi-directional prediction by means of motion compensation of inter-coded blocks, motion compensated temporal bidirectional prediction uses two reference video pictures in two separate reference video picture lists and two affine motion fields defined by at least two control point motion vectors, where the control point motion vectors are represented as CPMV, where the at least two control point motion vectors are associated with each reference picture, the refined CPMV is obtained as an output of a first step (171), or optionally as an output of a second step (172) following the first step (171). -in said first step (171), for each CPMV, performing bilateral matching on a block centered on said CPMV to derive at least two CPMVs refined with integer precision, and selecting a set of CPMVs comprising non-refined CPMVs and / or CPMVs refined with integer precision to produce an overall predicted block with minimum bilateral matching cost,-in said second step (172), selecting a set of CPMVs comprising non-refined CPMVs and / or CPMVs refined with integer precision to produce an overall predicted block with minimum bilateral matching cost. For each successive CPMV in the selected set of CPMVs associated with the block, each CPMV is refined at subsample accuracy to minimize bilateral matching costs for the block, where the second step (172) is bypassed according to a comparison between the bilateral matching costs associated with the CPMVs performed in the first step and a threshold.

A video coder is configured to receive a first block of video data to be coded using adaptive affine decoder side motion vector refinement (DMVR). The video coder may determine to set a first motion vector difference (MVD) for a first reference picture list to zero, and then refine control point motion vectors (CPMVs) associated with a second reference picture list to generate refined CPMVs. The video coder may then code the first block of video data using the refined CPMVs.

Processing circuitry determines an initial affine model with bi-prediction for a current block in an affine motion inter prediction mode, the initial affine model predicts the current block based on a first reference picture and a second reference picture. The processing circuitry performs a multi-stage bilateral matching motion refinement with at least a first stage and a second stage on the initial affine model to derive a refined affine model, one of the first stage and the second stage applies a first bilateral matching motion refinement on a translational component of the initial affine model, and the other of the first stage and the second stage applies a second bilateral matching motion refinement on a non-translational component of the initial affine model. The processing circuitry reconstructs the current block using the refined affine model based on the first reference picture and the second reference picture.

The disclosed aspects provide methods and apparatus for video encoding / decoding. In some examples, the apparatus for video decoding includes a processing circuit. The processing circuit receives a coded video bitstream including a current picture. The current picture includes a current block. The processing circuit determines, based on decoded information from the coded video bitstream, that the current block in the current picture is coded in an affine dual prediction mode. The current block is predicted by a plurality of control point motion vectors. The processing circuit refines the plurality of control point motion vectors by applying bilateral matching motion refinement and reconstructs the current block according to the refined plurality of control point motion vectors associated with the current block.

An image decoding method performed by means of a decoding device according to the present disclosure comprises the steps of: configuring an affine merge candidate list with respect to a current block; deriving CPMVs with respect to CPs of the current block on the basis of the affine merge candidate list; deriving prediction samples with respect to the current block on the basis of the CPMVs; and generating a reconstructed picture with respect to the current block on the basis of the derived prediction samples, wherein the maximum number of inherited affine candidates is two, a first inherited affine candidate is derived on the basis of a left block group of the current block, and a second inherited affine candidate is derived on the basis of an upper block group of the current block.

A decoder is configured to receive a bit stream including a current frame and a picture header associated with the entire current frame, determine, as a function of the picture header, that one global motion mode is enabled for the entire current frame, the enabled global motion mode being selected from a group including translational motion, 4-parameter affine motion, and 6-parameter affine motion, detect, based on the enabled global motion mode, a plurality of parameters applicable to the entire frame, and decode the current frame using the detected parameters.

Embodiments of the present specification provide an image filtering processing method, device, equipment, medium and program product, wherein the image filtering processing method comprises: screening a candidate affine motion region in a target image, and calculating a translation processing cost of the candidate affine motion region; obtaining affine motion information of the candidate affine motion region, and calculating an affine processing cost based on the affine motion information; in the case that the translation processing cost and the affine processing cost satisfy an affine strategy, determining the affine motion information as target motion information of the candidate affine motion region; performing filtering processing on the target motion information, the candidate affine motion region and a reference image block corresponding to the candidate affine motion region to obtain an affine filtering sub-block, and obtaining a filtering processing image based on each affine filtering sub-block and each translation filtering sub-block corresponding to the target image. When the affine strategy is satisfied, the affine motion information is used for subsequent filtering processing, and the robustness of image filtering in a complex motion scene is enhanced.

Implementations of the disclosure provide systems and methods for motion compensation prediction. The method may include obtaining a video block of a video frame from a bitstream. The method may further include performing a geometry partition on the video block to obtain a first partition and a second partition. The method may further include applying a first motion prediction mode to the first partition and a second motion prediction mode to the second partition. At least one of the first motion prediction mode or the second motion prediction mode is an affine motion prediction mode. The first motion prediction mode and the second motion prediction mode are a same coding mode with different parameters.

A current block is coded by an affine mode and includes a first control point at a first corner of the current block. A current template associated with the first control point is determined. A plurality of candidate reference templates is determined in a reference picture for the current template. A reference template is selected from the plurality of candidate reference templates for the current template based on a template matching (TM) cost. The TM cost indicates a respective difference between each candidate reference template and the current template of the first control point. A first control point motion vector (CPMV) is determined based on the selected reference template, where the first CPMV indicates an offset between the selected reference template in the reference picture and the current template associated with the first control point. The current block is reconstructed based at least on the first CPMV.

An affine motion compensation method and apparatus for video coding. According to one method, for a current block encoded using an affine model, a first motion vector (MV for short) is determined based on a bidirectional optical flow (Bi-Directional Optical Flow, BDOF for short) process. The second motion vector is determined on the basis of an optical flow prediction refinement (PROF) process, and the second motion vector is determined on the basis of the PROF process. And encoding or decoding the current block by using information including the first motion vector and the second motion vector. According to another method, an overlapping boundary motion compensation (OBMC) on / off state of a current block, an affine motion model of the current block, or both, is determined. An affine motion compensation (MC) block size of a current block is determined according to an OBMC on / off state of the current block, an affine motion model of the current block, or both, or whether sample-based or sub-block-based affine MC is allowed is determined according to the OBMC on / off state of the current block.

To provide an apparatus, an encoder, a decoder and corresponding methods for prediction refinement with optical flow (PROF) for an affine coded block.SOLUTION: A method includes, when a plurality of optical flow decision conditions are fulfilled for an affine coded block, performing a PROF process for a current sub-block of the affine coded block to obtain refined prediction sample values of the current sub-block of the affine coded block. After the sub-block based affine motion compensation is performed, a prediction sample value of the current sample of the current sub-block is refined by adding a delta prediction value. Thus, it allows for a better trade-off between coding complexity and prediction accuracy.SELECTED DRAWING: Figure 11A

Implementations of the disclosure provide systems and methods for motion compensation prediction. The method may include performing, by a video processor, a geometry partition on a video block of a video frame from a video to obtain a first partition and a second partition. The method may further include applying, by the video processor, a first motion prediction mode to the first partition and a second motion prediction mode to the second partition. At least one of the first motion prediction mode or the second motion prediction mode is an affine motion prediction mode.

A picture decoding method performed by a decoding apparatus according to the present disclosure includes obtaining motion prediction information from bitstream, generating an affine MVP candidate list including affine MVP candidates for a current block, deriving CPMVPs for respective CPs of the current block based on one of the affine MVP candidates included in the affine MVP candidate list, deriving the CPMVDs for the CPs of the current block based on information on CPMVDs for each of the CPs included in the obtained motion prediction information, deriving CPMVs for the CPs of the current block based on the CPMVPs and the CPMVDs, deriving prediction samples for the current block based on the CPMVs, and generating reconstructed samples for the current block based on the derived prediction samples.

A video decoder determines a current block of width (WCB) * height (HCB) in size to decode in an affine prediction mode; predicting each sub-block of the first plurality of sub-blocks using an affine motion model to determine an initial prediction block, each sub-block having a size of width (WSB) * height (HSB), and WSB being less than WCB and HSB being less than HCC; applying a bi-directional optical flow process to a first sub-block and a second sub-block of the second plurality of sub-blocks to determine a first refinement prediction sub-block and a second refinement prediction sub-block, each sub-block having a size of width (WSBIPB) * height (HSBIPB), WSBIPB being less than or equal to WCB and less than or equal to WSB, and HSBIPB being less than or equal to HCC and less than or equal to HSB; and determining a refined prediction block based on the first refined sub-block and the second refined sub-block.

The disclosure provides a method for decoding a video signal including a current block based on an affine motion prediction mode (affine mode, AF mode), the method including checking whether the AF mode is applied to the current block, the AF mode indicating a motion prediction mode using an affine motion model; when the AF mode is applied to the current block, checking whether the AF4 mode is used, the AF4 mode indicating a mode in which four parameters constituting the affine motion model are used to predict a motion vector; when the AF4 mode is used, generating a motion vector predictor using the four parameters, and when the AF4 mode is not used, generating a motion vector predictor using six parameters constituting the affine motion model; and obtaining a motion vector of the current block based on the motion vector predictor.

The present invention provides an encoding device that can efficiently perform motion compensation using affine motion compensation. [Solution] The encoding device 100 comprises a circuit 160 and a memory 162. The circuit 160 uses the memory 162 to perform motion compensation on the target block in the affine motion compensation prediction process in the inter prediction process of the target block by limiting the range in which motion search or motion compensation is performed. In the affine motion compensation prediction process, the range in which motion search or motion compensation is performed is limited so that the variation between the motion vector of the control point at the upper left corner and the motion vector of the control point at the upper right corner of the target block in the affine motion compensation prediction process falls within a predetermined range. The variation is a value based on the difference between the motion vector of the control point at the upper left corner and the motion vector of the control point at the upper right corner of the target block.

An example method includes obtaining, for a current block of video data, a value of a motion vector (MV) of an affine motion model of a neighboring block of video data, deriving, from the value of the MV of the affine motion model of the neighboring block, a value of a predictor of a MV of an affine motion model of the current block, decoding, from a video bitstream, a representation of a difference between the value of the MV of the affine motion model of the current block and the value of the predictor, determining the value of the MV of the affine motion model of the current block from the value of the predictor and the decoded difference, determining a predictor block of video data based on the determined value of the MV of the affine motion model of the current block, and reconstructing the current block based on the predictor block.

An apparatus configured to encode video data is configured to receive a first picture captured at a first time and a first location, receive a second picture captured at a second time and a second location, wherein the second time is different from the first time, and wherein the second location is different than the first location, and encode a current block of the second picture, relative to the first picture, using affine motion prediction with a single parameter search, wherein the single parameter search is performed along an epipolar curve, and wherein the single parameter search is used to determine parameters of an affine motion model.

A method includes determining, for a conversion between a video block of a video and a bitstream of the video, a size of prediction block corresponding to the video block according to a rule. The method also includes performing the conversion based on the determining. The rule specifies that a first size of the prediction block is determined responsive to whether a prediction refinement using optical flow technique is used for coding the video block. The video block has a second size and is coded using an affine merge mode or an affine advanced motion vector prediction mode.

The present disclosure relates to an image encoding / decoding method and device, wherein the image decoding method according to an embodiment of the present disclosure comprises the steps of: deriving an affine motion vector difference of the current block; deriving an affine motion vector of the current block on the basis of the affine motion vector difference; correcting the affine motion vector; deriving a motion vector of the current block on the basis of the corrected affine motion vector; and generating a prediction block of the current block on the basis of the motion vector of the current block, wherein the affine motion vector may be corrected on the basis of template matching.

The present disclosure relates to a method for deriving constructed affine merge candidates. The method includes acquiring one or more control point sets from a decoder. The decoder determines whether a reference index of each control point for the control point set index within the control point set associated with a reference index pointing into a reference picture in a first reference picture list is greater than or equal to zero and each is equal to each other. The decoder also determines whether a reference index of each control point for the control point set index within the control point set associated with a reference index pointing into a reference picture in a second reference picture list is greater than or equal to zero and each is equal to each other. The decoder determines that an affine motion model is available based on the determination result.