62 results about "Affine motion" patented technology

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.

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.

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.

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.

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 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.

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.

A picture decoding method implemented by a decoding device, according to the present invention, comprises the steps of: acquiring motion prediction information from a bitstream; generating an affine MVP candidate list comprising affine MVP candidates for the current block; deriving CPMVPs for the respective CPs of the current block on the basis of one affine MVP candidate among the affine MVP candidates included in the affine MVP candidate list; deriving CPMVDs for the CPs of the current block on the basis of information on the CPMVDs for the respective CPs included in the acquired motion prediction information; and deriving CPMVs for the CPs of the current block on the basis of the CPMVPs and the CPMVDs.

A video processing method for efficient affine Merge motion vector derivation is disclosed. In one aspect, a video processing method is provided, comprising: dividing a current video block into sub-blocks; deriving motion vectors for each sub-block, wherein the motion vector of each sub-block is associated with the position of the sub-block according to a positional rule; and using the motion vectors of the sub-blocks to process the bitstream representation of the current video block.

A video codec can involve processing video information based on a motion model involving a coding unit including a plurality of sub-blocks, such as an affine motion model, to produce motion compensation information, obtaining a local illumination compensation model, and encoding or decoding the video information based on the motion compensation information and the local illumination compensation model.

A video decoder may receive a block of video data to be decoded using a 6-parameter affine advanced motion vector predictor (AMVP) mode. The video decoder may decode a first syntax element indicating a first motion vector difference (MVD) for a first control point motion vector (CPMV) for the block, and also decode a flag that indicates if a second MVD for a second CPMV for the block and a third MVD for a third CPMV for the block are equal to the first MVD. The video decoder may further determine the second MVD and the third MVD based on the flag, and decode the block of video data using the first MVD, the second MVD, and the third MVD to generate a decoded block.

A VVC-standard encoder and a VVC-standard decoder are provided, implementing application of DMVR on affine merge mode-coded blocks to refine the motion vector accuracy and thereby improve coding efficiency. A refined motion vector (MV) search is performed for a control point motion vector (CPMV) of an inter-coded coding block (CB), outputting a refined MV of the CB. A refined MV search includes deriving a MV of a subblock of the CB based on a CPMV of the CB, performing subblock MV refinement for the MV of the subblock, and outputting the refined MV of the CB based on a refined MV of the subblock. A refined MV search further includes deriving an affine model parameter based on a plurality of CPMVs of the CB, performing an affine parameter offset search for the affine model parameter, and outputting the refined MV of the CB based on an optimal parameter offset.

The present 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 representing a motion prediction mode using an affine motion model; checking whether an AF4 mode is used when the AF mode is applied to the current block, the AF4 mode representing a mode in which a motion vector is predicted using four parameters constituting the affine motion model; generating a motion vector predictor using the four parameters when the AF4 mode is used and generating a motion vector predictor using six parameters constituting the affine motion model when the AF4 mode is not used; and obtaining a motion vector of the current block based on the motion vector predictor.

The present invention relates to a method by which a decoding apparatus performs image decoding, in accordance with the present document, comprising the steps of: obtaining motion prediction information about a current block from a bit stream; generating a list of affine MVP candidates for the current block; deriving CPMVPs for CPs of the current block based on the list of affine MVP candidates; deriving CPMVDs for the CPs of the current block based on the motion prediction information; deriving CPMVs for the CPs of the current block based on the CPMVPs and the CPMVDs; and deriving prediction samples for the current block based on the CPMVs.

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 differential (MVD) for a first reference picture list to 0 and then refine a CPMV associated with a second reference picture list to generate a refined control point motion vector (CPMV). The video coder may then code the first block of video data using the refined CPMV.

The present 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 representing a motion prediction mode using an affine motion model; checking whether an AF4 mode is used when the AF mode is applied to the current block, the AF4 mode representing a mode in which a motion vector is predicted using four parameters constituting the affine motion model; generating a motion vector predictor using the four parameters when the AF4 mode is used and generating a motion vector predictor using six parameters constituting the affine motion model when the AF4 mode is not used; and obtaining a motion vector of the current block based on the motion vector predictor.

In a method, a first affine-translational merge candidate is determined from a candidate list for a prediction of a current block in a current picture when the first affine-translational merge candidate for the prediction of the current block is allowed. The first affine-translational merge candidate provides affine motion information associated with a first reference picture in a first reference list and translational motion information associated with a second reference picture in a second reference list. A first prediction for a sample in the current block is generated according to the affine motion information associated with the first reference picture. A second prediction for the sample in the current block is generated according to the translational motion information associated with the second reference picture. The sample in the current block is encoded in a bitstream according to a combination of the first prediction and the second prediction.

An encoder includes circuitry and memory. Using the memory, the circuitry: in an inter prediction mode in which an affine motion vector is calculated for each of sub-blocks constituting a current block of a picture in the video, based on motion vectors of neighboring blocks of the current block, changes a shape or size of the sub-block according to a variation in direction or variation in magnitude among the motion vectors of the neighboring blocks; calculates the affine motion vector for the sub-block having the shape or size changed; and performs the motion compensation for the sub-block having the shape or size changed.

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.