Abstract: Video coding and decoding methods are described. In example method includes determining that a differential coding mode is applicable to a conversion between a current video block of a video and a bitstream representation of the current video block, and performing, based on the determining, the conversion between the current video block and the bitstream representation of the current video block using the differential coding mode according to an implementation rule, where, in the differential coding mode, the current video block is represented in the bitstream representation using a difference between a quantized residual of an intra prediction of the current video block and a prediction of the quantized residual, and where, in the differential coding mode, the difference between the quantized residual and the prediction of the quantized residual is represented using a differential pulse coding modulation (DPCM) representation.

Abstract: Devices, systems and methods for adaptive loop filtering are described. In an exemplary aspect, a method for video processing includes performing, for a current video block of a video, a filtering process that uses filter coefficients and comprises two or more operations with at least one intermediate result, applying a clipping operation to the at least one intermediate result, and performing, based on the at least one intermediate result, a conversion between the current video block and a bitstream representation of the video, wherein the at least one intermediate result is based on a weighted sum of the filter coefficients and differences between a current sample of the current video block and neighboring samples of the current sample.

Abstract: An example device includes a memory to store the video data, and processing circuitry in communication with the memory. The processing circuitry is configured to compare a value of a dimension of a current block of the stored video data to a value of a corresponding dimension of a neighboring block of the current block to obtain a relative dimension value. The processing circuitry is further configured to determine, based on the relative dimension value, that the current block is to be partitioned according to a prediction tree (PT) portion of a multi-type tree-based partitioning scheme. The PT portion comprises partitioning according to one of a binary tree structure or a center-side triple tree structure. The processing circuitry is further configured to partition, based on the determination, the current block according to the PT portion, to form a plurality of sub-blocks.

Abstract: An example device includes a memory to store the video data, and processing circuitry in communication with the memory. The processing circuitry is configured to compare a value of a dimension of a current block of the stored video data to a value of a corresponding dimension of a neighboring block of the current block to obtain a relative dimension value. The processing circuitry is further configured to determine, based on the relative dimension value, that the current block is to be partitioned according to a prediction tree (PT) portion of a multi-type tree-based partitioning scheme. The PT portion comprises partitioning according to one of a binary tree structure or a center-side triple tree structure. The processing circuitry is further configured to partition, based on the determination, the current block according to the PT portion, to form a plurality of sub-blocks.

Abstract: Devices, systems and methods for using zero-units in video and image coding are described. In a representative aspect, a method for processing video, including: determining, for a conversion between a block of the video and a bitstream of the video, that the block is a zero-unit (ZU) block based on at least one of the dimensions being a non-power-of-two number, wherein no transform and inverse-transform operations are performed on the block; performing the conversion based on the determination.

Abstract: Methods, systems and devices for using flexible and efficient partitioning techniques are described. An exemplary method for visual media decoding includes applying, to a current visual media block, a partitioning process that splits the current visual media block into more than four sub-blocks; decoding, based on a bitstream representation, the more than four sub-blocks; and decoding, based on the more than four sub-blocks and the partitioning process, the current visual media block. Another exemplary method for visual media encoding includes receiving input data associated with a current visual media block; applying, to the input data, a partitioning process that splits the current visual media block into more than four sub-blocks; encoding, based on the partitioning process, the more than four sub-blocks; and generating, based on the encoding, a bitstream representation of the current visual media block.

Abstract: A device for video decoding may include a memory configured to store video data and a processor configured receive a bitstream including encoded video data. The processor may be configured to select a number of template matching (TM) candidates for a temporal layer or slice during the video decoding. The number of TM candidates selected are fixed prior to the video decoding, or adaptively calculated during the video decoding. The processor may be configured to generate a prediction block and residual block, based on a template matching candidate, to reconstruct the video data.

Abstract: Devices, systems and methods for picture border coding are described. In a representative aspect, a method for processing pictures includes segmenting a picture into one or multiple picture segments, determining that a first block of a picture segment covers at least one region that is outside a border of the picture segment, wherein a size of the first block is M×N pixels, selecting a second block of size K×L pixels and where (K?M and L<N) or (K?M and L?N) and the second block falls entirely within the picture segment, and processing, using a partition tree, the border of the picture segment, wherein the partition tree is based on the size of the second block, wherein the processing includes splitting the second block into two or three sub-blocks without an indication on the splitting.

Abstract: Devices, systems and methods for picture border coding are described. In a representative aspect, a method for processing picture includes segmenting a picture into one or multiple picture segments, determining that a first block of a picture segment covers at least one region that is outside a border of the picture segment, wherein a size of the first block is M×N pixels, selecting a second block of size K×L pixels, where (K?M and L<N) or (K<M and L?N), wherein the second block falls entirely within the picture segment and wherein the second block is used as a largest coding unit, a leaf coding block or a coding tree block; and processing, using a partition tree, the border of the picture segment, wherein the partition tree is based on the size of the second block.

Abstract: Methods, systems and devices for using flexible and efficient partitioning techniques, and in particular, sub-block shapes in extended quadtree partitioning, are described. An exemplary method for visual media decoding includes applying, to a current visual media block, a partitioning process that splits the current visual media block into exactly four sub-blocks including at least one sub-block that has a size different from half of a width of the current visual media block times half of a height of the current visual media block, where a size of the current visual media block is M×N, and the size of the at least one sub-block is based on a minimum value between M and N, or a maximum value between M and N; decoding, based on a bitstream representation, the four sub-blocks; and decoding, based on the four sub-blocks and the partitioning process, the current visual media block.

Abstract: Techniques and systems are provided for processing video data. For example, a current block of a picture of the video data can be obtained for processing by an encoding device or a decoding device. A pre-defined set of weights for template matching based motion compensation are also obtained. A plurality of metrics associated with one or more spatially neighboring samples of the current block and one or more spatially neighboring samples of at least one reference frame are determined. A set of weights are selected from the pre-defined set of weights to use for the template matching based motion compensation. The set of weights is determined based on the plurality of metrics. The template matching based motion compensation is performed for the current block using the selected set of weights.

Abstract: Methods, systems and devices for using flexible and efficient partitioning techniques are described. An exemplary method for visual media decoding includes applying, to a current visual media block, a partitioning process that splits the current visual media block into exactly four sub-blocks including at least one sub-block that has a size different from half of a width of the current visual media block times half of a height of the current visual media block, decoding, based on a bitstream representation, the four sub-blocks, and decoding, based on the four sub-blocks and the partitioning process, the current visual media block.

Abstract: For a bi-directional inter predicted block, a video decoder is configured, using a first MV, to locate a first predictive block in a first reference picture; using a second MV, locate a second predictive block in a second reference picture; for a first sub-block of the first predictive block, determine a first amount of bi-directional optical flow (BIO) motion; determine a first final predictive sub-block for the block of video data based on the first amount of BIO motion; for a second sub-block of the first predictive block, determine a second amount of BIO motion; determine a second final predictive sub-block for the block of video data based on the second amount of BIO motion; and based on the first final predictive sub-block and the second final predictive sub-block, determine a final predictive block for the block of video data.

Abstract: Methods, systems and devices for using flexible and efficient partitioning techniques and in particular, restricting extended quadtree (EQT) partitioning, are described. An exemplary method for visual media decoding includes making a decision, based on one or more conditions, regarding a selective inclusion of one or more signaling bits for a partitioning process in a bitstream representation of a current visual media block of a plurality of visual media blocks, where the partitioning process splits the current visual media block into exactly four sub-blocks including at least one sub-block that has a size different from half of a width of the current visual media block times half of a height of the current visual media block; decoding, based on the bitstream representation, the four sub-blocks; and decoding, based on the four sub-blocks and the partitioning process, the current visual media block.

Abstract: Methods, systems and devices for using flexible and efficient partitioning techniques, and in particular, depth calculations for extended quadtree partitioning, are described. An exemplary method for visual media decoding includes applying, to a current visual media block, a partitioning process that splits the current visual media block into exactly four sub-blocks including at least one sub-block that has a size different from half of a width of the current visual media block times half of a height of the current visual media block; decoding, based on a bitstream representation, the four sub-blocks; and decoding, based on the four sub-blocks and the partitioning process, the current visual media block.

Abstract: A device for decoding video data is configured to perform interpolation filtering using an N-tap filter to generate an interpolated search space for a first block of video data; obtain a first predictive block in the interpolated search space; determine that a second block of video data is encoded using a bi-directional inter prediction mode and a bi-directional optical flow (BIO) process; perform an inter prediction process for the second block of video data using the bi-directional inter prediction mode to determine a second predictive block; perform the BIO process on the second predictive block to determine a BIO-refined version of the second predictive block, wherein a number of reference samples used for calculating intermediate values for BIO offsets is limited to a region of (W+N?1)×(H+N?1) integer samples, wherein W and H correspond to a width and height of the second block in integer samples.

Abstract: Techniques and systems are provided for processing video data. For example, a current block of a picture of the video data can be obtained for processing by an encoding device or a decoding device. A parameter of the current block can be determined. Based on the determined parameter of the current block, at least one or more of a number of rows of samples or a number columns of samples in a template of the current block and at least one or more of a number of rows of samples or a number columns of samples in a template of a reference picture can be determined. Motion compensation for the current block can be performed. For example, one or more local illumination compensation parameters can be derived for the current block using the template of the current block and the template of the reference picture.

Abstract: A method of decoding video comprising: receiving an encoded block of video data, determining a transform for the encoded block of video data, wherein the transform has a size S that is not a power of two, rounding S to a power of two creating a transform with a modified size S?, applying an inverse transform with the modified size S? to the encoded block of video data to create residual video data, and decoding the residual video data to create decoded block of video data.

Abstract: A method of decoding video data includes determining, by a video decoder implemented in circuitry, a bi-predicted MV predictor for a block of video data. The bi-predicted MV predictor indicates a first input reference block and a second input reference block. The method further includes refining, by the video decoder, the bi-predicted MV predictor using gradient information to determine a refined bi-predicted MV predictor indicating a first refined reference block that is within a search range from the first input reference block and a second refined reference block that is within the search range from the second input reference block. The method further includes generating, by the video decoder, a predictive block for the block of video data based on the refined bi-predicted MV predictor, and decoding, by the video decoder, the block of video data based on the predictive block.

Abstract: Techniques and systems are provided for processing video data. For example, video data can be obtained for processing by an encoding device or a decoding device. Bi-predictive motion compensation can then be performed for a current block of a picture of the video data. Performing the bi-predictive motion compensation includes deriving one or more local illumination compensation parameters for the current block using a template of the current block, a first template of a first reference picture, and a second template of a second reference picture. The templates can include neighboring samples of the current block, the first reference picture, and the second reference picture. The first template of the first reference picture and the second template of the second reference picture can be used simultaneously to derive the one or more local illumination compensation parameters.