A video decoding method according to the present disclosure may include determining whether an affine motion model is applied to a current block or not, performing motion compensation for the current block according to whether the affine motion model is applied or not, determining a value of a first variable and a second variable representing whether a prediction block obtained by the motion compensation will be refined and determining a padding size of the prediction block.

A method, computer program, and computer system is provided for video coding. Coded syntax elements corresponding to wrap-around padding process are decoded. At least one coded current picture is reconstructed using wrap-around padding process. The syntax elements indicate an offset value for wrap-around processing; or left and right padding width information. A flag indicates whether syntax elements corresponding to wrap-around padding process is present in parameter set. A pixel position for motion compensated prediction in a reference picture is determined by interpreting the syntax elements corresponding to wrap-around padding process with a clipping process.

A video coding system (e.g., an encoder and/or a decoder) may perform face-based sub-block motion compensation for 360-degree video to predict samples (e.g., of a sub-block). The video coding system may receive a 360-degree video content. The 360-degree video content may include a current block. The current block may include a plurality of sub-blocks. The system may determine whether a sub-block mode is used for the current block. The system may predict a sample in the current block based on the sub-block level face association. For a first sub-block in the current block, the system may identify a first location of the first sub-block. The system may associate the first sub-block with a first face based on the identified first location of the first sub-block. The system may predict a first sample in the first sub-block based on the first face that is associated with the first sub-block.

A video coding system (e.g., an encoder and/or a decoder) may perform face-based sub-block motion compensation for 360-degree video to predict samples (e.g., of a sub-block). The video coding system may receive a 360-degree video content. The 360-degree video content may include a current block. The current block may include a plurality of sub-blocks. The system may determine whether a sub-block mode is used for the current block. The system may predict a sample in the current block based on the sub-block level face association. For a first sub-block in the current block, the system may identify a first location of the first sub-block. The system may associate the first sub-block with a first face based on the identified first location of the first sub-block. The system may predict a first sample in the first sub-block based on the first face that is associated with the first sub-block.

A method of encoding a three-dimensional (3D) image including a point cloud includes grouping a plurality of points included in the point cloud into at least one segment; generating patches by projecting the points included in the segment onto a predetermined plane in a first direction or a second direction; generating two-dimensional (2D) images by packing the patches; and generating and outputting a bitstream including information about a direction in which each point is projected to generate the patches and information about the 2D images.

The present disclosure relates to motion vector determination using template or bilateral matching and predictor generation based on the motion vector. The template or bilateral matching and/or the predictor generation use interpolation filtering. The interpolation filtering operation accesses integer sample positions within a window, and further uses padded sample values for integer sample positions outside the window, which are based on at least one sample within said window, and uses the accessed integer sample position values as well as the padded sample values to perform the template or bilateral matching and/or predictor generation.

The present disclosure relates to motion vector determination using template or bilateral matching and predictor generation based on the motion vector. The template or bilateral matching and/or the predictor generation use interpolation filtering. The interpolation filtering operation accesses integer sample positions within a window, and further uses padded sample values for integer sample positions outside the window, which are based on at least one sample within said window, and uses the accessed integer sample position values as well as the padded sample values to perform the template or bilateral matching and/or predictor generation.

The invention relates to the encoding of spherical 360-degree videos using 2D block-based encoders. The encoding requires a spherical 360-degree image to be projected onto a projection subpart of a 2D image, using for instance CMP, OHP, ISP, TSP, SSP or RSP techniques. The boundary of the projected image may then be extended, within the 2D image, into an extended block-based boundary portion based on the block structure used by the 2D encoder to then encode the 2D image. The boundary extension may be set along block edges in the vicinity of the projected image. The extended pixels added to the projected image may be padding pixels with values set based on continuing 360-degree image projection or based on neighboring pixels. More homogenous blocks can be obtained for better compression by the encoder, while the seam artefacts resulting from discontinuity between projected subparts of the 360-degree image are reduced.

A video processing method is provided to include determining, for a current video block of a video, a final prediction block for the current video block by refining one or more initial predictions for the current video block using an optical flow calculation based on a gradient of initial prediction samples according to a precision rule; and performing a conversion between the current video block and a coded representation using the final prediction block, wherein the optical flow calculation includes a prediction refinement with optical flow (PROF) procedure or a bi-directional optical flow (BDOF) procedure, wherein the precision rule specifies to use a same precision for representing the gradient for both the PROF procedure and the BDOF procedure.

A video processing method is provided to include determining, for a current video block of a video, a final prediction block for the current video block by refining one or more initial predictions for the current video block using an optical flow calculation based on a gradient of initial prediction samples according to a precision rule; and performing a conversion between the current video block and a coded representation using the final prediction block, wherein the optical flow calculation includes a prediction refinement with optical flow (PROF) procedure or a bi-directional optical flow (BDOF) procedure, wherein the precision rule specifies to use a same precision for representing the gradient for both the PROF procedure and the BDOF procedure.