Abstract: Techniques are described in which a decoder is configured to receive an input data block and apply an inverse non-separable transform to at least part of the input data block to generate an inverse non-separable transform output coefficient block. The applying the inverse non-separable transform comprises assigning a window, assigning a weight for each position inside the assigned window, and determining the inverse non-separable transform output coefficient block based on the assigned weights. The decoder is further configured to forming a decoded video block based on the determined inverse non-separable transform output coefficient block, wherein forming the decoded video block comprises summing the residual video block with one or more predictive blocks.

Abstract: A video coding device (e.g., a video encoder or a video decoder) is configured to perform various transformations on video data. The video coding device applies a primary transform to a block of the video data, the primary transform having a first size, and the sub-block being at least a portion of the block. The video coding device determines whether application of a secondary transform, having a second size, to a sub-block of the block is allowed. Application of the secondary transform is disallowed when the first size is equal to the second size. Based on the application of the secondary transform being allowed, the video coding device applies the secondary transform to the sub-block. Application of the primary transform and the secondary transform construct a residual block in a pixel domain.

Abstract: A video encoder may determine a set of quantization offset parameters for a group of scaled transform coefficients for a block of video data based on side information associated with the block of video data. The video encoder may further quantize the group of scaled transform coefficients for the block of video data to generate quantized transform coefficients for the block of video data based at least in part on the set of quantization offset parameters. The video encoder may further generate an encoded video bitstream based at least in part on the quantized transform coefficients for the block of video data.

Abstract: A device for coding video data is configured to determine that a current block of video data is coded using an intra prediction mode; add an intra prediction mode of a first neighboring block of the current block to a most probable mode candidate list for the current block; add an intra prediction mode for a second neighboring block of the current block to the most probable mode candidate list for the current block; add an intra prediction mode for a third neighboring block of the current block to the most probable mode candidate list for the current block; and code the current block of video data using an intra prediction mode.

Abstract: A video decoder can be configured to receive, in a syntax structure that applies to a current block, graph-related information; determine a transform matrix based on the received graph-related syntax information; perform an inverse transform based on the determined transform matrix of one or more coefficient values to generate a residual block; and reconstruct the current block of the video data based on the residual block.

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 video coder may generate a predictor block using an intra prediction mode. As part of generating the predictor block, the video coder may, for each respective sample in a set of samples in the predictor block, determine, based on an initial value of the first weight and a distance between the respective sample and a first boundary of the predictor block, a value of the first weight for the respective sample. Additionally, the video coder may determine, based on the initial value of the second weight and a distance between the respective sample and a second boundary of the predictor block, a value of the second weight for the respective sample. The video coder may also determine a primary value for the respective sample. The video coder may then determine a secondary value for the respective sample based on the first weight, second weight, and the primary value.

Abstract: An example device for decoding video data includes a memory configured to store the video data and one or more processors coupled to the memory. The one or more processors are configured to reorganize 2-D dequantized coefficients according to a first ordering. The one or more processors are configured to apply an inverse low-frequency non-separable transform (LFNST) to the reorganized 2-D dequantized coefficients to create inverse transformed coefficients. The one or more processors are configured to reorganize the inverse transformed coefficients according to a second ordering, the second ordering being based on an array including values, wherein each value in the array corresponds to a position in a 2-D block and the values in the array denote indices of the 2-D block in a defined order. The one or more processors are configured to decode the video data based on the second ordered inverse transformed coefficients.

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: Techniques are described of hybrid coders that are configured to selectively use adaptive or non-adaptive coding techniques. A video coder (e.g., video encoder or video decoder) may code (e.g., encode or decode) first video data (e.g., a syntax element or value), for coding a first block, based on an adaptive context model (e.g., one or more adaptive context models) and code second video data, for coding a second block, based on a non-adaptive context model (e.g., one or more non-adaptive context models).

Abstract: Techniques are described in which a decoder is configured to inverse quantize a first coefficient block and apply a first inverse transform to at least part of the inverse quantized first coefficient block to generate a second coefficient block. The first inverse transform is a non-separable transform. The decoder is further configured to apply a second inverse transform to the second coefficient block to generate a residual video block. The second inverse transform converts the second coefficient block from a frequency domain to a pixel domain. The decoder is further configured to form a decoded video block, wherein forming the decoded video block comprises summing the residual video block with one or more predictive blocks.

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 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: Disclosed herein is a method of encoding a video signal, comprising receiving an original video signal; comparing the original video signal with available reconstructed signals; generating a transform-coded correction signal based on a result of the comparison; generating a prediction signal based on the transform-coded correction signal and the available reconstructed signals; and reconstructing a signal by adding the transform-coded correction signal to the prediction signal.

Abstract: An example device for coding video data includes a memory configured to store video data; and one or more processors implemented in circuitry and configured to: code a first codeword representing a selected transform scheme of a set of transform candidates of a multiple transform selection (MTS) scheme for a current block of video data, the selected transform scheme being a secondary transform of a set of available secondary transforms to be applied in addition to a primary transform; code a second codeword representing the secondary transform from the set of available secondary transforms; and apply the primary transform and the secondary transform during coding of residual data for the current block. The second codeword may be a value for a low-frequency non-separable transform (LFNST) syntax element.

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: An example method for entropy decoding of video data includes retrieving a pre-defined initialization value for a context of a plurality of contexts used in a context-adaptive entropy coding process to entropy code a value for a syntax element for an independently codable unit of video data; determining, based on the pre-defined initialization value and in a linear domain, an initial probability state of the context; and entropy decoding, from a bitstream and based on the initial probability state of the context, a bin of the value for the syntax element.

Abstract: An example method includes inferring, for a current transform block of a current video block, a transform type from a plurality of transform types that includes one or more discrete cosine transforms (DCTs) and one or more discrete sine transforms (DSTs), wherein inferring the transform type comprises: determining a size of the current transform block; determining whether the current video block is partitioned using intra-subblock partitioning (ISP); and responsive to determining that the size of the current transform block is less than a threshold and that the current video block is partitioned using ISP, selecting a particular DST of the one or more DSTs as the selected transform type; transforming, using the selected transform type, the current transform block to obtain a block of reconstructed residual data for the video block; and reconstructing, based on the reconstructed residual data for the video block, the video block.

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: An example device for decoding video data includes a memory configured to store video data and one or more processors implemented in circuitry and configured to determine a maximum possible value for a secondary transform syntax element for a block of video data, entropy decode a value for the secondary transform syntax element of the block to form a binarized value representative of the secondary transform for the block, reverse binarize the value for the secondary transform syntax element using a common binarization scheme regardless of the maximum possible value to determine the secondary transform for the block, and inverse-transform transform coefficients of the block using the determined secondary transform.