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.

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: 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 method of encoding video data includes transforming residual values using a pair of transforms, wherein the pair of transforms are a mirror pair of asymmetric transforms. The transform comprises determining matrices for a low-complexity transform adjustment stage for each of the pair of transforms, calculating matrices for each of the pair of transforms from a low-complexity transform and the matrices for the low-complexity transform adjustment stage, and transforming the residual values using the calculated matrices for each of the pair of transforms to produce transform coefficients.

Abstract: Techniques are described in which a decoder is configured to reorganize a first 2-dimensional coefficient block as a first 1-dimensional coefficient vector according to a coefficient scanning order and apply a first inverse transform to the first 1-dimensional coefficient vector to generate a second 1-dimensional coefficient vector. The first inverse transform is a non-separable transform. The decoder is further configured to reorganize the first 1-dimensional coefficient vector as a second 2-dimensional coefficient block and apply a second inverse transform to the second 2-dimensional coefficient block to generate a residual video block. The second inverse transform converts the second 2-dimensional 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: 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: Sign prediction technology for video coding are generally described. An example device includes a memory configured to store video data, and processing circuitry in communication with the memory. The processing circuitry is configured to determine that a block of the video data stored to the memory is eligible to be coded using sign prediction, to perform the sign prediction with respect to one or more transform coefficients of the block only if the block meets a predetermined criterion, wherein the predetermined criterion is based on at least one of: a width of the block, a height of the block, a coding mode used to code the block, or a position of one or more sign-predicted transform coefficients within the block, and to code the block based on the sign prediction performed with respect to the block.

Abstract: A method of decoding video data that includes receiving a current block of video data encoded using an intra prediction mode, determining residual video data for the current block of video data, determining reference samples of the current block of video data, determining filter coefficients for a bilateral filter based on a distance between the reference samples and neighboring reference samples and based on a sample value difference between the reference samples and the neighboring reference samples, applying the bilateral filter with the determined filter coefficients to the determined reference samples to produce filtered reference samples, generating a prediction block using the filtered reference samples, and adding samples of the prediction block to the determined residual video data to produce a decoded block of video data.

Abstract: An example device for decoding encoded video data includes storage media and processing circuitry. The storage media are configured a portion of the encoded video data. The processing circuitry is configured to determine a block-level threshold for the portion of the encoded video data stored to the storage media, to determine that an encoded block of the portion of the encoded video data has a size that is equal to or greater than the threshold, to receive a syntax element indicating that a portion of the encoded block is to be reconstructed using a coding tool, to determine, based on the encoded block having the size that is equal to or greater than the threshold, that the syntax element applies to all samples of a plurality of samples included in the encoded block, and to reconstruct the encoded block based on the coding tool.

Abstract: A device includes processing circuitry configured to identify a set of pre-stored residual samples in video data that is stored to a memory, to combine the set of stored residual samples to form a combination, to apply a first sign combination to transform coefficients of the combination to obtain a first hypothesis reconstruction for a current block of the video data, and to apply a second sign combination to the transform coefficients of the combination to obtain a second hypothesis reconstruction for the current block. The processing circuitry is further configured to derive respective cost functions with respect to the first and second hypothesis reconstructions, to compare the respective derived cost functions, to select, based on the comparison, either the first or second hypothesis reconstruction, and to code the current block using a sign prediction associated with the selected one of the first or second hypothesis reconstruction.

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: 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 comprises receiving a bitstream of encoded video data, the encoded video data representing partitioned luma blocks and partitioned chroma blocks, wherein the chroma blocks are partitioned independently of the luma blocks, determining a respective coding mode corresponding to the respective partitioned luma blocks, decoding the respective partitioned luma blocks according to the determined respective coding modes, decoding a first syntax element indicating that the respective coding modes associated with the respective partitioned luma blocks are to be used for decoding a first partitioned chroma block, wherein the first partitioned chroma block is aligned with two or more partitioned luma blocks, determining a chroma coding mode for the first partitioned chroma block according to a function of the respective coding modes of the two or more partitioned luma blocks, and decoding the first partitioned chroma block in accordance with the determined chroma coding mode.

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: For at least one respective bin of the bin stream, a decoder may determine, based on a state for the respective bin, an interval for the respective bin, and the offset value, a value of the respective bin. Additionally, the decoder determines one or more Finite State Machine (FSM) parameters for a next bin of the bin stream. The one or more FSM parameters for the next bin controls how probability estimates for the next bin are computed from a state for the respective bin. The decoder determines using a parameterized state updating function that takes as input the state for the respective bin, the one or more FSM parameters for the next bin of the bin stream, and the value of the respective bin, a state for the next bin of the bin stream. The decoder may debinarize the bin stream to form a decoded syntax element.

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: 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: Techniques are described to improved video intra prediction using position-dependent prediction combination in video coding. In High Efficiency Video Encoding a set of 35 linear predictors are used for doing intra coding and prediction can be computed from either a nonfiltered or a filtered set of neighboring “reference” pixels, depending on the selected predictor mode and block size. Techniques of this disclosure may use a weighted combination of both the nonfiltered and filtered set of reference pixels to achieve better compression via improved prediction and therefore small residual, enable effective parallel computation of all sets of prediction values, and maintain low complexity via applying filtering only to a set of reference pixels and not to predicted values themselves.

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.