Abstract: Methods and devices for decoding including a processor configured to determine which picture is a collocated picture, and determine a location of an associated block of the video data in the collocated picture that corresponds to the current block of video data in the current coding picture, based on using previously decoded blocks in the current coding picture to find an initial motion vector between the associated block in the collocated picture and the current block in the current coding picture, where the associated block of the video data includes at least one first derived motion vector. The processor configured to determine at least one second derived motion vector associated with the current block in the current coding picture, when the initial motion vector points to the collocated picture, based on the at least on first derived motion vector associated with the associated block in the collocated picture.

Abstract: An example device for filtering a decoded block of video data includes one or more processing units configured to construct filters for classes of blocks of a current picture of video data. To construct 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 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: A device for processing video data includes a memory configured to store video data and one or more processors implemented in circuitry. The one or more processors are configured to obtain unfiltered reference samples for an area of a picture of the video data. The one or more processors are configured to disable intra-reference sample smoothing of the unfiltered reference samples for chroma samples in a YUV 4:2:0 format and in a YUV 4:4:4 format. The one or more processors are further configured to generate, using intra-prediction, chroma samples of a predicted block for a block of the picture based on the unfiltered reference samples when generating the chroma components in the YUV 4:2:0 format and when generating the chroma components in the YUV 4:4:4 format.

Abstract: This disclosure provides systems, devices, apparatus, and methods, including computer programs encoded on storage media, for truncation error signaling and adaptive dither for lossy bandwidth compression. A processor may perform a truncation process for data, where the data is associated with display processing, image processing, or the data processing, where the truncation process for the data results in truncated data. The processor may compute a set of truncation error values associated with the truncation process for the truncated data. The processor may generate a set of residual samples for the truncated data. The processor may generate a bitstream based on the set of residual samples for the truncated data and the set of truncation error values associated with the truncation process.

Abstract: An example method includes encoding, in a video bitstream, a first syntax element specifying whether affine model based motion compensation is enabled; based on affine model based motion compensation being enabled, encoding, in the video bitstream, a second syntax element specifying a maximum number of subblock-based merging motion vector prediction candidates, wherein a value of the second syntax element is constrained based on a value other than a value of the first syntax element; and encoding a picture of the video data based on the maximum number of subblock-based merging motion vector prediction candidates.

Abstract: An example device for encoding high dynamic range (HDR) video data includes a memory configured to store video data; and one or more processors implemented in circuitry and configured to: calculate a histogram for an image of the video data, the image being expressed in a linear light format; encode values for the histogram of the image expressed in the linear light format; and encode the image. Data for the histogram may be expressed in an array of variables having a size of 210×18 bits. The device may encode codewords representing values for bins of the histogram, where the codewords may be selected from a set of codewords for a PQ10 format for HDR images. The bins of the histogram may represent non-equal width ranges.

Abstract: This disclosure describes gradient-based prediction refinement. A video coder (e.g., video encoder or video decoder) determines one or more prediction blocks for inter-predicting a current block (e.g., based on one or more motion vectors for the current block). In gradient-based prediction refinement, the video coder modifies one or more samples of the prediction block based on various factors such as displacement in a horizontal direction, the horizontal gradient, a displacement in the vertical direction, and a vertical gradient. This disclosure provides for gradient-based prediction refinement where a precision level of the displacement (e.g., at least one of the horizontal or vertical displacement) is unified (e.g., the same) for different prediction modes.

Abstract: A device and method for coding video data is described. The device may generate filtered samples by performing, in a predicted samples domain, interpolation filtering and a second filtering from a group of one or more of: an adaptive filter, a domain transform filter, a scaler, or a local illumination compensation (LIC). The device may generate one or more of: residual data based on the filtered samples, or reconstructed samples based on the filtered samples; and code the video data based on one or more of the residual data or the reconstructed samples.

Abstract: A method of encoding video data includes determining an integer sample in a reference picture of the video data; determining, based on the integer sample, at least a first fractional sample and a second fractional sample, wherein the first fractional sample has a first fractional pel resolution, and the second fractional sample has a second fractional pel resolution different from the first fractional pel resolution; subsequent to determining both the first fractional sample and the second fractional sample, determining a first cost metric associated with the first fractional sample and a second cost metric associated with the second fractional sample; determining a reference block for a current block based on at least one of the first cost metric or the second cost metric; and encoding the current block based on the reference block.

Abstract: An example device for encoding high dynamic range (HDR) video data includes a memory configured to store video data; and one or more processors implemented in circuitry and configured to: calculate a histogram for an image of the video data, the image being expressed in a linear light format; encode values for the histogram of the image expressed in the linear light format; and encode the image. Data for the histogram may be expressed in an array of variables having a size of 210×18 bits. The device may encode codewords representing values for bins of the histogram, where the codewords may be selected from a set of codewords for a PQ10 format for HDR images. The bins of the histogram may represent non-equal width ranges.

Abstract: Systems and techniques are provided for processing video data. For example, the systems and techniques can include obtaining a current picture of video data and obtaining reference pictures for the current picture from the video data. A merge mode candidate can be determined for the current picture. First and second motion vectors can be identified for the merge mode candidate. A motion vector search strategy can be selected for the merge mode candidate from a plurality of motion vector search strategies. The selected motion vector search strategy can be associated with one or more constraints corresponding to at least one of the first motion vector or the second motion vector. The selected motion vector search strategy can be used to determine refined motion vectors based on the first motion vector, the second motion vector, and the reference pictures. The merge mode candidate can be processed using the refined motion vectors.

Abstract: A device for decoding video data can be configured to receive a syntax element indicating a maximum block size for a transform skip mode; determine a maximum block size for a block-based delta pulse code modulation (BDPCM) mode based on the syntax element; and decode block of video data based on the determined maximum block size for the BDPCM mode.

Abstract: A video encoder and/or video decoder may determine the size of subblocks of a block of video data, where the block of video data is to be encoded or decoded using subblock affine motion compensation mode. The video encoder and/or video decoder may receive a block of video data to be coded using a subblock affine motion compensation mode, determine a size of one or more subblocks of the block based on one or more of an inter prediction direction or affine motion parameters of the block, partition the block into the one or more subblocks based on the determined size, and code the one or more subblocks using the subblock affine motion compensation mode.

Abstract: A video coder is configured to determine bi-directional motion vectors of a current block of the video data and determine that a condition is satisfied with respect to the current block based on each component of the bi-directional motion vectors of the current block being less than a threshold value. The video coder is further configured to, based on the condition being satisfied with respect to the current block, early terminate application of a motion vector refinement process to the bi-directional motion vectors of the current block. The video coder is further configured to determine a prediction block for the current block based on the bi-directional motion vectors of the current block and reconstruct the current block based on the prediction block for the current block.

Abstract: A video coder can be configured to code video data by determining a first block size threshold for a block of video data; determining a second block size threshold, wherein the second block size threshold is smaller than the first block size threshold; partitioning the block of video data into smaller sub-blocks; in response to determining that a first partition of the partitioned block is smaller or equal to the first block size threshold, determining that blocks within the partition belong to a parallel estimation area; and in response to determining that a second partition of the partitioned block is smaller or equal to the second block size threshold, determining that blocks within the second partition belong to an area for a shared candidate list.

Abstract: A device for encoding video data includes a memory configured to store video data, and a video encoder implemented in circuitry and configured to encode a future picture of the video data having a first display order position, the future picture being included in an intra period (IP) of the video data, the IP comprising a plurality of groups of pictures (GOPs), and after encoding the future picture, encode a picture of an ordinal first GOP of the plurality of GOPs using the future picture as a reference picture, each picture of the ordinal first GOP having display order positions earlier than the first display order position. Encoding the future picture in this manner may result in encoding performance improvements with minimal increases in encoding and decoding complexity.

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 encoding, in a video bitstream, a first syntax element specifying whether affine model based motion compensation is enabled; based on affine model based motion compensation being enabled, encoding, in the video bitstream, a second syntax element specifying a maximum number of subblock-based merging motion vector prediction candidates, wherein a value of the second syntax element is constrained based on a value other than a value of the first syntax element; and encoding a picture of the video data based on the maximum number of subblock-based merging motion vector prediction candidates.

Abstract: A video coder may determine a motion vector of a non-adjacent block of a current picture of the video data. The non-adjacent block is non-adjacent to a current block of the current picture. Furthermore, the video coder determines, based on the motion vector of the non-adjacent block, a motion vector predictor (MVP) for the current block. The video coder may determine a motion vector of the current block. The video coder may also determine a predictive block based on the motion vector of the current block.