Abstract: An example device applies a primary transform to a current block of video data to create primary transform coefficients. The device determines whether intra sub-partitioning is applied to the current block of video data. The device applies a primary transform to the current block. The device also determines whether a primary transform size for the current block of video data is at least a predetermined size. Based on intra sub-partitioning being applied and the primary transform size being at least the predetermined size, the device applies a secondary transform to primary transform coefficients and codes the current block of video data based on the secondary transform.

Abstract: This disclosure describes techniques for managing filter information for use with adaptive loop filter or any other in-loop filter in video encoder or decoder. In particular, a temporal buffer is managed to store filter coefficients for pictures of a group of pictures based on whether a picture is the starting point the group of pictures.

Abstract: A video decoder may receive, in a bitstream that comprises an encoded representation of video data, information indicating whether a residual block is partitioned and information indicating a partition tree type for the residual block based on the residual block being partitioned, wherein the residual block is indicative of a difference between a current block and a prediction block. The video decoder may determine, based on the received information that the residual block is partitioned and the partition tree type for the residual block, a plurality of residual sub-blocks into which the residual block is partitioned according to the partition tree type. The video decoder may produce the residual data for the current block based at least in part on the residual block being partitioned according to the partition tree type into the plurality of residual sub-blocks and may decode the current block using the residual data.

Abstract: The present invention provides a method for decoding a video signal using a graph-based transform including receiving a generalized graph signal including a graph parameter set; obtaining a graph-based transform kernel of a transform unit based on the graph parameter set and a predetermined penalty function; and decoding the transform unit using the graph-based transform kernel.

Abstract: Techniques are described for improving transform coding. For example, an encoded block of video data can be obtained, and a width and/or a height of the block can be determined. The width can be compared to a first threshold and/or the height can be compared to a second threshold. A horizontal transform and a vertical transform can be determined for the block based on comparing the width of the block to the first threshold and/or the height of the block to the second threshold. The horizontal transform and the vertical transform are determined without decoding a syntax element that indicates the horizontal transform and the vertical transform (e.g., the syntax element is not in an encoded video bitstream processed by a decoding device). In some cases, residual data is determined using the horizontal and vertical transforms, and a video block is determined using the residual data and a predictive block.

Abstract: A device for decoding video data includes a memory configured to store video data and one or more processors implemented in circuitry and configured to store sets of adaptive loop filter (ALF) parameters in a one-dimensional array in the memory, the one-dimensional array having a predefined size of N memory elements, N being a positive integer value, wherein the one or more processors are configured to store, in one or more of the memory elements of the array, both corresponding ALF parameters and a temporal layer identifier (ID) value indicating a temporal layer from which the corresponding ALF parameters are to be estimated; decode one or more blocks of the video data; and filter the one or more blocks using the ALF parameters of the one-dimensional array. The device may further encode the one or more blocks prior to decoding the one or more blocks.

Abstract: A method and a device for decoding a video signal using an adaptive separable graph-based transform. The method includes: receiving a transform index for a target block from the video signal in which the transform index indicates a graph-based transform to be applied to the target block; deriving a graph-based transform kernel corresponding to the transform index; and decoding the target block based on the graph-based transform kernel. The device includes: a parsing unit configured to receive a transform index for a target block from the video signal; and an inverse-transform unit configured to derive a graph-based transform kernel corresponding to the transform index and decode the target block based on the graph-based transform kernel.

Abstract: This disclosure describes examples of extending the number of available discrete cosine transform (DCT) and discrete sine transform (DST) for encoding and decoding. A video coder may determine one or more transforms or inverse transforms to apply from a set of transforms or inverse transforms that includes DCT-2 or inverse DCT-2, DST-7 or inverse DST-7, DST-8 or inverse DST-8, DCT-3 or inverse DCT-3, DST-2 or inverse DST-2, DST-3 or inverse DST-3, DCT-4 or inverse DCT-4, DST-4 or inverse DST-4, DST-5 or inverse DST-5, DST-6 or inverse DST-6, and identity transform an inverse identity transform (IDT).

Abstract: An example coding device, such as a video coding (encoding or decoding) device is configured to determine a plurality of estimator functions to be used to calculate a probability of a symbol having a particular value, wherein the symbol is to be binary arithmetic coded according to the probability, and wherein the estimator functions do not include division operations; determine a plurality of weights for the plurality of estimator functions such that when the respective weights are applied to the estimator functions, a resulting sum of outputs of the plurality of estimator functions yields the probability; calculate the probability of the symbol having the particular value, including: execute the estimator functions without using the division operations to determine the outputs; and calculate a sum of the outputs as the probability; and binary arithmetic code the symbol according to the probability of the symbol having the particular value.

Abstract: An example device for decoding video data includes a memory configured to store video data; and a processor implemented in circuitry and configured to decode a truncated unary codeword representing a multiple transform (MT) scheme for a current block of the video data to determine the MT scheme; apply the MT scheme to transform coefficients of the current block to produce residual data for the current block of video data; and decode the current block using the residual data. The MT scheme may include a plurality of transforms, such as a horizontal transform and a vertical transform, a primary transform and a second transform, or any combination of separable and/or non-separable transforms. Thus, a single truncated unary codeword may represent the entire MT scheme, that is, each of a plurality of transforms of the MT scheme.

Abstract: A device may perform a first prediction process for a first block of video data to produce a first residual. The device may apply a first transform process to the first residual to generate first transform coefficients for the first block of video data and encode the first transform coefficients. The device may perform a second prediction process for a second block of video data to produce a second residual. The device may determine that a second transform process, which includes the first transform process and at least one of a pre-adjustment operation or a post-adjustment operation, is to be applied to the second residual. The device may apply the first transform process and the pre- or post-adjustment operation to the second residual to generate second transform coefficients for the second block. The coding device may code the first and second transform coefficients.

Abstract: A device for decoding video data can be configured to perform a multi-pass inverse transformation on a plurality of values to derive residual data that represents pixel differences between a current block of video data and a predictive block of the video data, wherein to perform a pass of the multi-pass inverse transformation, the device is configured to determine at least two matrices, wherein the at least two matrices comprise a first matrix and a second matrix; determine at least two vectors, wherein the at least two vectors comprise a first vector and a second vector; and perform at least two matrix-vector computations, wherein the at least two matrix-vector computations comprise a first matrix-vector computation based on the first matrix and the first vector and a second matrix-vector computation based on the second matrix and the second vector.

Abstract: Performing a graph-based prediction using a graph signal can be performed using a method that includes obtaining a context signal; generating a graph signal based on a graph parameter set; obtaining a graph-based transform matrix based on the graph signal, wherein the graph-based transform matrix includes an eigenvector; obtaining a prediction vector using an optimal transform vector calculated through an optimization function; and generating a prediction signal using the prediction vector, where the optimization function has the context signal, an eigenvalue of a graph Laplacian matrix and the eigenvector as a variable. Accordingly, a prediction value may be obtained with reduced complexity and the prediction performance may be improved.

Abstract: A method for decoding a video signal using a graph-based transform, where the method includes: receiving a template index for a target unit from the video signal, wherein the template index indicates a graph-based transform template to be applied to the target unit; deriving a graph-based transform matrix for the target unit corresponding to the template index; and decoding the target unit based on the graph-based transform matrix. In some scenarios, this enables efficient compression of inter-predicted residual blocks by using graph-based transform templates. The graph-based transform template may enable adaptive transform selection, thus achieving improved coding gain. Further, by defining a graph-based transform template or a template index, coding with a low-complexity is enabled that can reduce the number of bits to be transmitted to the decoder.

Abstract: Disclosed herein is a method of processing a graph-based signal using a geometric primitive, comprising: specifying the geometric primitive to be used for calculating an edge weight; obtaining a parameter for each of the geometric primitive; calculating an edge weight for each of edges within the image based on the parameter; and encoding the image based on the edge weight.

Abstract: A method of decoding video data includes receiving, by processing circuitry, a video bitstream including encoded representations of one or more syntax elements of a coded unit and initializing, by the processing circuitry, a respective probability state for each bin of a plurality of bins for the one or more syntax elements based on a comparison of a parameter associated with the coded unit and a respective threshold of a plurality of thresholds. The method further includes performing, by the processing circuitry, inverse binary arithmetic coding on the encoded representations of the one or more syntax elements to obtain each bin of the plurality of bins using a respective probability state for the bin, inverse binarizing, by the processing circuitry, the plurality of bins to obtain the one or more syntax elements, and decoding, by the processing circuitry, the video data based on the one or more syntax elements.

Abstract: A video decoder can be configured to generate a first bin stream by, for at least one bin of the first bin stream, determining a first probability estimation for the at least one bin of the first bin stream based on a first set of parameters and generate a second bin stream by, for at least one bin of the second bin stream, determining a second probability estimation for the at least one bin of the second bin stream based on a second set of parameters that are different parameters than the first set of parameters.

Abstract: The present invention provides a method for decoding a video signal using an adaptive separable graph-based transform, comprising the steps of: receiving a transform index for a target block from the video signal, wherein the transform index indicates a graph-based transform to be applied to the target block; deriving a graph-based transform kernel corresponding to the transform index; and decoding the target block based on the graph-based transform kernel.

Abstract: The present invention provides a method for performing a graph-based prediction using a graph signal including obtaining a context signal; generating a graph signal based on a graph parameter set; obtaining a graph-based transform matrix based on the graph signal, wherein the graph-based transform matrix includes an eigenvector; obtaining a prediction vector using an optimal transform vector calculated through an optimization function; and generating a prediction signal using the prediction vector, where the optimization function has the context signal, an eigenvalue of a graph Laplacian matrix and the eigenvector as a variable.

Abstract: The present invention provides a method for decoding a video signal using a graph-based transform including receiving a generalized graph signal including a graph parameter set; obtaining a graph-based transform kernel of a transform unit based on the graph parameter set and a predetermined penalty function; and decoding the transform unit using the graph-based transform kernel.