Abstract: The present invention provides a method for encoding a video signal by using an enhanced prediction signal, the method comprising the steps of: generating a prediction signal for a current block, wherein the prediction signal is generated by applying a prediction weight to a reconstructed pixel of the current block and a pixel of a motion-compensated previously decoded block; obtaining an optimal quantized transform coefficient for the current block through rate-distortion optimization, on the basis of the prediction signal; and performing entropy encoding of the optimal quantized transform coefficient.

Abstract: Systems and methods for decoding a video stream, a method includes receiving video stream, the video stream including: a frame of a plurality of two-dimensional (2D) pictures that are layers of the frame, each of the plurality of 2D pictures having a respective attribute of a same three-dimensional (3D) representation, frame partition information that indicates the frame is partitioned into a plurality of sub-frames, each of the plurality of sub-frames being a respective combination of a sub-region of each picture of the plurality of 2D pictures, and 3D bounding box information that specifies a 3D position corresponding to a sub-frame of the plurality of sub-frames; the method further includes identifying the sub-frame using the frame partition information; and decoding the sub-frame identified.

Abstract: An image decoding method, which is performed by a decoding apparatus, includes the steps of: deriving a frequency domain-neighboring block for a neighboring block of a current block in a spatial domain; deriving a frequency domain-prediction block for the current block by applying a prediction pattern to the frequency domain-neighboring block; generating a frequency domain-reconstructed block for the current block on the basis of the frequency domain-prediction block; and generating a reconstructed block for the current block in the spatial domain on the basis of the frequency inverse transform of the frequency domain-reconstructed block. The present invention can generate a prediction block for a current block in a frequency domain, and accordingly can more efficiently reconstruct a complex image.

Abstract: The present invention provides a method for encoding a video signal on the basis of a graph-based lifting transform (GBLT), comprising the steps of: detecting an edge from an intra residual signal; generating a graph on the basis of the detected edge, wherein the graph includes a node and a weight link; acquiring a GBLT coefficient by performing the GBLT for the graph; quantizing the GBLT coefficient; and entropy-encoding the quantized GBLT coefficient, wherein the GBLT includes a partitioning step, a prediction step, and an update step.

Abstract: Aspects of the disclosure provide methods and apparatuses for point cloud compression and decompression. In some examples, an apparatus for point cloud compression/decompression includes processing circuitry. For example, the apparatus is for point cloud decompression. The processing circuitry decodes prediction information of an image from a coded bitstream corresponding to a point cloud. The prediction information indicates that the image includes a plurality of missed points from at least a patch for the point cloud, and the plurality of missed points are arranged in the image according to a non-jumpy scan. Then, the processing circuitry reconstructs the plurality of missed points from the image according to the non-jumpy scan.

Abstract: A method and apparatus for decoding a video stream encoded using video point cloud coding, the decoding including obtaining a geometry-reconstructed point cloud based on one or more patches; identifying a first boundary of a patch including a plurality of first boundary points; identifying a second boundary including a plurality of second boundary points inside the first boundary; performing smoothing on the first boundary points and the second boundary points; obtaining a smoothed geometry-reconstructed point cloud based on the smoothed first boundary points and the smoothed second boundary points; and reconstructing a dynamic point cloud using the smoothed geometry-reconstructed point cloud.

Abstract: Aspects of the disclosure provide methods and apparatuses for point cloud compression and decompression. In some examples, an apparatus for point cloud compression/decompression includes processing circuitry. In some embodiments, the processing circuitry decodes prediction information of a point cloud from a coded bitstream and reconstructs a geometry reconstructed cloud according to a geometry image of the point cloud that is decoded from the coded bitstream. Further, the processing circuitry applies a filter to at least a geometry sample inside a patch of the geometry reconstructed cloud in addition to boundary samples of the patch to generate a smoothed geometry reconstructed cloud, and reconstructs points of the point cloud based on the smoothed geometry reconstructed cloud.

Abstract: Aspects of the disclosure provide methods and apparatuses for point cloud compression and decompression. In some examples, an apparatus for point cloud compression/decompression includes processing circuitry. For example, the processing circuitry of the apparatus for point cloud encoding determines, from a point cloud, more than two candidate source points that are associated with a target point in a reconstructed geometry reconstructed from a compressed geometry image for the point cloud. Then the processing circuitry determines a color for the target point based on colors of the more than two candidate source points, and encodes texture of the point cloud with the target point having the determined color.

Abstract: Aspects of the disclosure provide methods and apparatuses for point cloud compression and decompression. In some examples, an apparatus for point cloud compression/decompression includes processing circuitry. For example, the processing circuitry in the apparatus for point cloud encoding receives an occupancy map for a point cloud. The occupancy map is indicative of a background portion and a foreground portion for a coding block in an image that is generated based on the point cloud. Then, the processing circuitry devaluates distortions in the background portion of the coding block during an optimization process that results a coding option for the coding block, and encodes the coding block according to the coding option.

Abstract: An image decoding method, which is performed by a decoding device according to the present invention, comprises the steps of: acquiring the information on an intra-prediction mode of a current block from a received bit stream; deriving neighboring reference samples of the current block; deriving a first prediction value for a current sample of the current block on the basis of the intra-prediction mode and the neighboring reference samples; deriving a second prediction value for the current sample on the basis of adjacent samples of the current sample; and deriving a prediction value for the current sample on the basis of the first prediction value and the second prediction value. According to the present invention, the intra-prediction value can be derived on the basis of the adjacent samples of the current sample within the present block, and the intra-prediction accuracy can be improved therethrough.

Abstract: The present invention provides a method of decoding a video signal using graph-based transform comprising the steps: extracting prediction unit partition information of a current coding unit from the video signal; obtaining a graph-based transform kernel from predetermined table information based on the prediction unit partition information; and performing an inverse-transform of a transform unit using the graph-based transform kernel, wherein the graph-based transform kernel corresponds to at least one of the prediction unit partition information and an edge weight, and the edge weight is a predetermined value representing a correlation between pixels.

Abstract: An intra prediction method includes: receiving intra prediction mode information through a bitstream; deriving an intra prediction mode of a current block as a first intra directional mode on the basis of the intra prediction mode information; deriving first neighboring samples of the current block; deriving a reference sample adjacent to a target sample in the current block on the basis of a prediction direction of the first intra directional mode; deriving second neighboring samples of a neighboring block to which the reference sample belongs; determining a modified prediction direction on the basis of a comparison between the reference sample and at least one of the second neighboring samples; and deriving a prediction value for the target sample on the basis of the modified prediction direction and the first neighboring samples.

Abstract: The present invention provides a method for encoding a video signal by using a single optimized graph, comprising the steps of: obtaining a residual block; generating graphs from the residual block; generating an optimized graph and an optimized transform by combining the graphs, wherein the graphs are combined on the basis of an optimization step; and performing a transform for the residual block on the basis of the optimized graph and the optimized transform.

Abstract: Methods and apparatuses of decoding a video stream encoded using video point cloud coding include obtaining a geometry-reconstructed point cloud; dividing the geometry-reconstructed point cloud into a plurality of cells; obtaining a first reference point including a centroid of a first plurality of points; generating a second plurality of points by applying a first filter to the first plurality of points based on the first reference point; obtaining a second reference point including a centroid of the second plurality of points; generating a third plurality of points by applying a second filter to the second plurality of points based on the second reference point, wherein a strength of the first filter is higher than a strength of the second filter; obtaining a smoothed geometry-reconstructed point cloud based on the third plurality of points; and reconstructing a dynamic point cloud using the smoothed geometry-reconstructed point cloud.

Abstract: A method of dynamic point cloud partition packing is by at least one processor and includes obtaining one or more region of interest (ROI) patches from an ROI of a point cloud, and attempting to pack, into one among tiles of a tile map, one among the obtained one or more ROI patches, in a tile scan order. The method further includes identifying whether the one among the one or more ROI patches is packed successfully into the one among the tiles, and based on the one among the one or more ROI patches being determined to be not packed successfully into the one among the tiles, chunking the one among the one or more ROI patches into multiple ROI patches.

Abstract: Methods and apparatuses of decoding a video stream encoded using video point cloud coding include obtaining a geometry-reconstructed point cloud; dividing the geometry-reconstructed point cloud into a plurality of cells, wherein a cell of the plurality of cells includes a first plurality of points; determining a plane representing the first plurality of points; generating a second plurality of points by projecting the first plurality of points onto the plane; obtaining a smoothed geometry-reconstructed point cloud based on the second plurality of points; and reconstructing a dynamic point cloud using the smoothed geometry-reconstructed point cloud.

Abstract: A method and apparatus for encoding a video stream using video point cloud coding, the decoding including obtaining an input point cloud; dividing the input point cloud into a plurality of chunks, including a first chunk including a first plurality of points and a second chunk including a second plurality of points; generating a first plurality of patches based on the first plurality of points; generating a second plurality of patches based on the second plurality of points; packing the first plurality of patches and the second plurality of patches into an image; and generating the video stream based on the image.

Abstract: Disclosed in the present invention are a method for encoding/decoding an image and a device for same. Particularly, a method for decoding an image may comprise the steps of: parsing a filter index from a bit stream outputted from an encoder; determining a filter set using the filter index, from among a plurality of filter sets belonging to a predetermined filter bank; deriving a filter coefficient based on a coefficient for filtering, defined by the filter set, which has been determined by the filter index; and applying filtering to a reconstructed image obtained using a prediction signal and a differential signal, by using the derived filter coefficient.

Abstract: An image decoding method performed by a decoding apparatus according to the present invention comprises the steps of: generating a reconstruction area for a target area within a current picture; deriving a predetermined plurality of basic filters for the target area; updating at least one basic filter among the plurality of basic filters; receiving weight information for each of the basic filters; determining a merge filter for the target area on the basis of the basic filters and the weight information; and generating a modified reconstruction area by performing filtering on the target area on the basis of the filter coefficient of the determined merge filter. The present invention allows updating with filter information suitable for improving the visual quality of the target area and can thereby improve the accuracy of filtering and overall coding efficiency.

Abstract: A method of video decoding performed in a video decoder includes receiving compressed geometric data corresponding to a three dimensional (3D) space. The method further includes receiving a low resolution occupancy map associated with the data cloud. The method further includes converting the low resolution occupancy map to a high resolution occupancy map. The method further includes reconstructing a point cloud using the compressed geometric data and the high resolution occupancy map. The method further includes performing a smoothing operation on one of the (i) reconstructed point cloud and (ii) the high resolution occupancy map.