Abstract: An example device for filtering a decoded block of video data includes one or more processing units configured to construct a plurality of filters for classes of blocks of a current picture of video data. To construct the plurality of filters for each of the classes, the processing units are configured to determine a value of a flag that indicates whether a fixed filter is used to predict a set of filter coefficients of the class, and in response to the fixed filter being used to predict the set of filter coefficients, determine an index value into a set of fixed filters and predict the set of filter coefficients of the class using a fixed filter of the set of fixed filters identified by the index value.

Abstract: An example method of decoding video data includes obtaining, from a coded video bitstream and for a current block of the video data, an indication of an intra-prediction mode that identifies an initial predictive block; filtering, in parallel, samples in a current line of a plurality of lines of the initial predictive block based on filtered values of samples in a preceding line of the plurality of lines and unfiltered values of samples in the current line to generate filtered values for samples for the current line; and reconstructing, using intra prediction, values of samples of the current block based on the filtered values of the samples of the current initial predictive block and residual data for the current block that represents a difference between the filtered values of the samples of the current initial predictive block and the values of samples of the current block.

Abstract: An example method includes obtaining values of luma motion vectors for a plurality of luma sub-blocks of a current block of the video data selected for coding using affine motion compensation; determining, based on values of luma motion vectors of a sub-set of the plurality of luma sub-blocks, a value of a chroma motion vector for a chroma sub-block that corresponds to the plurality of luma sub-blocks; predicting, using affine motion compensation, respective samples of each luma sub-block of the plurality of luma sub-blocks based on respective values of the luma motion vectors; and predicting, using affine motion compensation, sample the chroma sub-block based on the value of the chroma motion vector.

Abstract: An example device for coding video data includes a memory configured to store video data; and one or more processing units implemented in circuitry and configured to: store motion information for a first coding tree unit (CTU) line of a picture in a first history motion vector predictor (MVP) buffer of the memory; reset a second history MVP buffer of the memory; and after resetting the second history MVP buffer, store motion information for a second CTU line of the picture in the second history MVP buffer, the second CTU line being different than the first CTU line. Separate threads of a video coding process executed by the one or more processors may process respective CTU lines, in some examples.

Abstract: Techniques for processing video data are described. The techniques include determining a first partition and a second partition for a current block coded in geometric partition mode, determining a first and second prediction block based on a first and second motion vector, blending the first prediction block and the second prediction block based on weights indicative of an amount to scale samples in the first prediction block and the second prediction block to generate a final prediction block, dividing the current block into a plurality of sub-blocks, determining a set of sub-blocks that each include at least one sample that corresponds to a prediction sample in the final prediction block that was generated based on equal weighting of a sample in the first prediction block and a sample in the second prediction block, and storing respective bi-prediction motion vectors for each sub-block in the determined set of sub-blocks.

Abstract: A video encoder and video decoder may determine a set of adaptive loop filters, from among a plurality of sets of adaptive loop filters, on a per-block basis. Each set of adaptive loop filters may include filters from a previous picture, filters signaled for the current picture, and/or pre-trained filter. By varying the set of adaptive loop filters on a per-block basis, the adaptive loop filters available for each block of video data may be more adapted to local statistics of the video data.

Abstract: A video decoder obtains a first triangle merging index syntax element specifying a first triangle merging candidate index. The first triangle merging candidate index indicates a first triangle merging candidate of a triangular shape-based motion compensation candidate list. The video decoder may determine whether the maximum number of triangle merging candidates is greater than 2. Based on the maximum number of triangle merging candidates not being greater than 2, the video decoder may infer that a second triangle merging candidate index indicates a second triangle merging candidate of the triangular shape-based motion compensation candidate list without obtaining any syntax element specifying the second triangle merging candidate index from the bitstream, the second triangle merging candidate being different from the first triangle merging candidate.

Abstract: A video coder determines a first block of the video data is intra mode coded; based on a first height and the first width of the first block, identifies a group of N available intra prediction modes for the first block of video data; selects from the group of N available intra prediction modes, a first intra prediction mode used to code the first block of the video data; and codes the first block using the first intra prediction mode. A video coder generates a first most probable mode (MPM) candidate list for the block; codes a first flag indicating an actual intra prediction mode used to code the block is not included in the first MPM candidate list; generates a second MPM candidate list by deriving at least one candidate intra prediction mode based on an intra prediction mode in the first MPM candidate list.

Abstract: A video encoder and video decoder are configured to encode and decode blocks of video data using affine motion prediction. Affine motion prediction may include predicting control point motion vectors using an affine advanced motion vector prediction (AMVP) motion vector predictor list. The video encoder and video decoder may be configured to construct the affine AMVP motion vector predictor list of candidate control point motion vectors for the block of video data, wherein the affine AMVP motion vector predictor list includes one or more affine motion vector predictors that have all control point motion vectors equal to a designated motion vector.

Abstract: An example method includes decoding, from a coded video bitstream, an explicitly defined scaling list; determining, based on values of one or more syntax elements decoded from a sequence parameter set (SPS) of the coded video bitstream, a set of block types to which the explicitly defined scaling list is eligible for application; and applying the explicitly defined scaling list to a block included in the set of block types.

Abstract: A method of processing video data includes determining, by processing circuitry, a plurality of neighboring samples for predicting a current block. The plurality of neighboring samples are arranged outside of a region of a current picture, the region comprising the current block, a row of samples adjacent to a top row of the current block, and a column of samples adjacent to a left column of the current block. The method further comprises deriving, by the processing circuitry, local illumination compensation information for the current block using the plurality of neighboring samples and generating, by the processing circuitry, a prediction block using the local illumination compensation information.

Abstract: An example method includes determining, for each respective coding block of a plurality of coding blocks of a current coding tree unit (CTU) of video data in a current picture of video data, a respective search area of a plurality of respective search areas, wherein at least one of the plurality of search areas includes samples of the current picture located outside of the current CTU, and wherein at least one of the plurality of search areas does not include samples of the current picture located outside of the current CTU; selecting, for each respective coding block and from within the respective search area for the respective coding block, a respective predictor block of a plurality of predictor blocks; and reconstructing samples of each respective coding block based on samples included in a corresponding predictor block in the plurality of predictor blocks.

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 coding device is configured to determine control point motion vectors (CPMVs) for an affine motion predicted block of video data. For a four parameter affine model, two CPMVs may be positioned at any two corners of the current block, such as top-left and bottom-right or bottom-left; top-right and bottom-left or bottom-right; or bottom-left and bottom-right. For a six parameter affine model, three CPMVs may be positioned at any three corners of the current block, such as top-left, bottom-left, and bottom-right; top-right, bottom-left, and bottom-right; or top-left, top-right, and bottom-right. The video coder may further predict the CPMVs using motion information of neighboring blocks to the determined CPMVs, code the CPMVs, and code the current block using the CPMVs. The video coder may be a video encoder or a video decoder.

Abstract: An example device includes a memory and processing circuitry in communication with the memory. The processing circuitry of a device is configured to form a most probable mode (MPM) candidate list for a chroma block of the video data stored to the memory, such that the MPM candidate list includes one or more derived modes (DMs) associated with a luma block of the video data associated with the chroma block, and a plurality of luma prediction modes that can be used for coding luminance components of the video data. The processing circuitry is further configured to select a mode from the MPM candidate list, and to code the chroma block according to the mode selected from the MPM candidate list.

Abstract: A video decoder can be configured to determine, for a block of video data encoded in a geometric partition mode, an angle for the block for the geometric partition mode; determine a separation line displacement relative to a center of the block for the geometric partition mode; partition the block into first and second partitions based on the angle and the separation line displacement; determine first predictive samples for the block using a motion vector for the first partition and second predictive samples for the block using a motion vector for the second partition; determine a power-of-2 number based on the angle for the block; determine weighting values based on the power-of-2 number; perform a blending operation on the first predictive samples and the second predictive samples based on the weighting values to determine a prediction block for the block.

Abstract: An example device for filtering a decoded block of video data includes one or more processing units configured to construct a plurality of filters for classes of blocks of a current picture of video data. To construct the plurality of filters for each of the classes, the processing units are configured to determine a value of a flag that indicates whether a fixed filter is used to predict a set of filter coefficients of the class, and in response to the fixed filter being used to predict the set of filter coefficients, determine an index value into a set of fixed filters and predict the set of filter coefficients of the class using a fixed filter of the set of fixed filters identified by the index value.

Abstract: A video decoder can be configured to determine that a block of the video data is formatted in accordance with a 4:4:4 video coding format; determine that the block of the video data is encoded in an intra prediction mode; determine that a smallest chroma intra prediction unit (SCIPU) is disabled for the block in response to determining that the block has the 4:4:4 video coding format; decode the block of the video data based on the determination that the SCIPU is disabled; and output decoded video data comprising a decoded version of the block.

Abstract: A video coding 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 current block of the video data stored to the memory is to be coded according to a merge mode, and to determine a temporal candidate associated with a merge candidate list for the current block in accordance with the merge mode. The processing circuitry is further configured to determine a pool of spatial candidates associated with the merge candidate list, based on each spatial candidate of the pool having a same reference picture as the temporal candidate, and to set a local illumination compensation (LIC) flag value for the temporal candidate based on respective LIC flag values of one or more spatial candidates of the pool.

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.