Abstract: The present invention provides a method for encoding a video signal on the basis of a graph-based separable transform (GBST), the method comprising the steps of: generating an incidence matrix representing a line graph; training a sample covariance matrix for rows and columns from the rows and columns of a residual signal; calculating a graph Laplacian matrix for rows and columns on the basis of the incidence matrix and the sample covariance matrix for rows and columns; and obtaining a GBST by performing eigen decomposition of the graph Laplacian matrix for rows and columns.

Abstract: The present invention provides a method for encoding a video signal based on an Edge Adaptive Graph-Based Transform (EA-GBT) including detecting a step edge or a ramp edge from a residual signal; generating a graph signal based on at least one of the step edge or the ramp edge; obtaining an EA-GBT coefficient by performing the EA-GBT for the graph signal; quantizing the EA-GBT coefficient; and entropy-encoding the quantized EA-GBT coefficient.

Abstract: A method of decoding video data includes determining that a current block of the video data is coded in palette mode, determining, between single tree or dual tree partitioning, that the current block is coded with single tree partitioning enabled, determining that the current block is coded in monochrome format, when the current block is coded with single tree partitioning enabled and when the current block is coded in monochrome format, determining that a number of color components used for palette mode decoding the current block is equal to one, and palette mode decoding the current block based on the determined number of color components used for palette mode decoding the current block being equal to one.

Abstract: Systems and techniques for intra-block copy (IBC) prediction in processing video data include the use of one or more virtual search areas (VSAs) which can be generated to include one or more references to one or more pixels stored in a physical memory. The one or more VSAs can provide references to additional reconstructed sample values that are derived from previously decoded blocks without incurring physical memory use for storage of the additional reconstructed samples. A search area for performing the IBC prediction for a current block of the video data can be extended to include the one or more VSAs. Extending the search area to include the one or more VSAs provides the IBC prediction with additional search area for finding one or more prediction blocks or prediction samples without having to utilize physical memory to store the additional reconstructed samples from previously decoded blocks.

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 decoder may be configured to determine whether a block of video data is to be further partitioned based on the size of the block of video data and a lossless coding flag. A video decoder may decode a lossless coding flag for a block of video data, wherein the block of video data is in a picture that includes both lossy coded blocks and lossless coded blocks, determine that the lossless coding flag indicates a lossless coding mode for the block, and partition the block into sub-blocks based on a size of the block and the determination of the lossless coding mode.

Abstract: Embodiments are directed to systems and methods of using rice code in video coding. In one embodiment includes a method of encoding or decoding video data, e.g., on a video encoder or decoder. The method includes determining available residual coefficients neighboring a current position in a transform unit of video data and determining a sum of the available residual coefficients. The method further includes modifying the sum based on the number of available residual coefficients and determining a rice parameter based on the modified sum. The method further includes encoding or decoding a syntax element of video data based on the determined rice parameter.

Abstract: An example device includes a memory configured to store at least a portion of an encoded video bitstream; and one or more processors that are implemented in circuitry and configured to: determine, based on a parameter of a first block of video data, a maximum number of entries to be used for palette-mode coding of the current block; generate, based on the determined maximum number of entries and based on a palette predictor, a palette for the first block of video data, the palette including one or more entries each including a palette index that is associated with a color value; decode, from the encoded video bitstream and for the first block of video data, index values for samples of the first block that identify entries in the palette; and reconstruct, based on the index values, the samples of the first block.

Abstract: Embodiments include systems and methods of generating merge candidates for an inter-prediction mode of a video block. In particular, embodiments include methods of generating spatial-temporal motion vector predictor candidates. Embodiments may include video encoders and video decoders.

Abstract: A method of decoding video data comprising performing a prediction process for one or more neighboring blocks of video data that are neighboring a current block of video data to obtain prediction pixel values for neighboring pixels of the current block of video data, deriving a template for the current block of video data using the prediction pixel values, performing a decoder-side motion vector derivation technique using the derived template to derive a motion vector for the current block of video data, and decoding the current block of video data using the derived motion vector.

Abstract: A method of decoding video data includes receiving a value indicating that a lossless mode is enabled for a block of the video data and, in response to determining that the value indicates that the lossless mode is enabled for the block of the video data, determining a maximum size for a lossless-coded transform block of the block of the video data is set to a maximum scanning size of the non-lossless coding block. The method further includes inverse scanning residual values for the block of the video data based on the maximum size for the lossless-coded transform block to generate a residual block for the block of the video data and reconstructing the block of the video data based on the residual block.

Abstract: Systems, methods, and computer-readable storage media for maintaining palette predictors for palette coding are described. An example method can include determining a current palette coding block of a single tree coded slice of a picture is encoded according to a local dual tree; determining, after an update of a palette predictor associated with the current palette coding block, a first number of palette predictor entries for a first image component of the current palette coding block and a second number of palette predictor entries for a second image component of the current palette coding block; determining the first number of palette predictor entries is greater than the second number of palette predictor entries; and based on the first number being greater than the second number, modifying the updated palette predictor to include a same number of palette predictor entries for the first and second image component.

Abstract: An example device for decoding video data includes a memory for storing the video data and one or more processors implemented in circuitry and communicatively coupled to the memory. The one or more processors are configured to determine whether a first coding unit (CU) is a skip mode CU, and based on the first CU not being a skip mode CU, determine whether the first CU is encoded using one of an intra mode or a palette mode. The one or more processors are also configured to determine whether the first CU is encoded using the palette mode based on the first CU being encoded using one of the intra mode or the palette mode. The one or more processors are also configured to decode the first CU based on the determination of whether the first CU is encoded using the palette mode.

Abstract: A method of decoding video data includes receiving encoded data for a current block of the video data, the current block comprising one or more escape mode encoded samples and decoding, from the encoded data, a value indicating that the current block includes the one or more escape mode encoded samples. The method further includes, in response to determining that the value indicates that the current block includes the one or more escape mode encoded samples and that a current tree type for the current block is not dual tree chroma, decoding an absolute value for a luma delta quantization parameter for the current block and a sign for the luma delta quantization parameter. The method further includes reconstructing the current block based on the absolute value for the luma delta quantization parameter for the current block and the sign for the luma delta quantization parameter.

Abstract: A method of coding video data comprising determining a quantization group (QG) based on one or more of a size of a CU splitting node and a value of a region-based parameter, determining a single quantization parameter for all blocks of video data within the determined quantization group, and performing a quantization process on transform coefficients of all blocks of video data within the determined quantization group using the determined single quantization parameter.

Abstract: A video encoder derives a minimum allowed base quantization parameter for video data based on an input bitdepth of the video data, determines a base quantization parameter for a block of the video data based on the minimum allowed base quantization parameter, and quantizes the block of video data based on the base quantization parameter. In a reciprocal fashion, a video decoder derives a minimum allowed base quantization parameter for the video data based on an input bitdepth of the video data, determines a base quantization parameter for a block of the video data based on the minimum allowed base quantization parameter, and inverse quantizes the block of video data based on the base quantization parameter.

Abstract: Examples of block-level signaling of quantization parameter offsets is described. Such block-level signaling of quantization parameter offsets provides block level flexibility to determine a more precise chroma quantization parameter (QP) for a chroma block. With the block-level quantization parameter offset signaling described in this disclosure, there is more flexibility in defining the chroma QP, resulting in more accurate determination of chroma QP on a chroma block-by-chroma block basis.

Abstract: A method for encoding a raw lenselet image includes a receiving phase, wherein at least a portion of a raw lenselet image is received, the image including a plurality of macro-pixels, each macro-pixel having pixels corresponding to a specific view angle for the same point of a scene, and an output phase, wherein a bitstream having at least a portion of an encoded lenselet image is outputted. The method has an image transform phase, wherein the pixels of said raw lenselet image are spatially displaced in a transformed multi-color image having a larger number of columns and rows with respect to the received raw lenselet image, wherein dummy pixels having undefined value are inserted into the raw lenselet image and wherein the displacement is performed so as to put the estimated center location of each macro-pixel onto integer pixel locations.

Abstract: A video decoder can be configured to determine a predicted luma quantization parameter (QP) for a luma component of a coding unit; receive, in the bitstream of encoded video data, first syntax indicating a luma delta QP value for the luma component; determine a QP value for the luma component based on the predicted luma QP and the luma delta QP value; determine a predicted chroma QP for a chroma component of the coding unit; receive, in the bitstream of encoded video data, second syntax indicating a chroma delta QP value for the chroma component of the coding unit; and determine a QP value for the chroma component of the coding unit based on the predicted chroma QP and the chroma delta QP value.

Abstract: A video decoder can be configured to determine that a block of video data is encoded without transforming residual data for the block; determine a quantization parameter for the block of video data; based on the determined quantization parameter, determine a range for levels of quantized residual values of the block; divide the range into k intervals, wherein k is an integer value; determine a level for a quantized residual value of the block based on the k intervals by receiving information indicating the level for the quantized residual value is within a particular interval of the k intervals, receiving information indicating a difference value that represents a difference between a reference level value for the particular interval and the level for the quantized residual value of the block, and based on the reference level value and the difference value, determining the level for the quantized residual value.