Abstract: A method of coding video data includes determining that chroma related syntax elements of the video data are present for luma mapping with chroma scaling (LMCS) for a coding unit (CU) of the video data, coding a syntax element of the video data when the chroma related syntax elements are present for LMCS for the CU, the syntax element is indicative of a value for determining a scaling parameter for chroma scaling in LMCS, and coding a chroma block of the CU based on the scaling parameter for chroma scaling.

Abstract: A video encoder may transform residual data by using a transform selected from a group of transforms. The transform is applied to the residual data to create a two-dimensional array of transform coefficients. A scanning mode is selected to scan the transform coefficients in the two-dimensional array into a one-dimensional array of transform coefficients. The combination of transform and scanning mode may be selected from a subset of combinations that is based on an intra-prediction mode. The scanning mode may also be selected based on the transform used to create the two-dimensional array. The transforms and/or scanning modes used may be signaled to a video decoder.

Abstract: Disclosed are systems, methods, apparatuses, and computer-readable media for processing video data. For instance, an apparatus for processing video data, may include: at least one memory; and at least one processor coupled to the at least one memory, the at least one processor being configured to: obtain a bitstream; retrieve a granularity type syntax element associated with the bitstream, the granularity type syntax element specifying a type of granularity of one or more pictures over which complexity metrics (CM) associated with the bitstream are applicable; retrieve a period type syntax element associated with the bitstream, the period type syntax element indicating an upcoming period of time or a set of pictures over which the CM are applicable; and decode a portion of the bitstream based on the granularity type syntax element and the period type syntax element.

Abstract: A video coder is configured to determine a reference block of a reference picture for prediction of a current block of a current picture using motion information and to generate a set of reference samples for the current block of the current picture. To generate the set of reference samples, the video coder is configured to perform reference sample clipping on the reference block of the reference picture based on a size of the reference picture. The video coder is further configured to generate a prediction block for the current block of the current picture based on the set of reference samples.

Abstract: A method of processing video data comprises performing a bitstream conformance process that determines whether a bitstream that comprises an encoded representation of the video data conforms to a video coding standard, wherein the bitstream conformance process determines that the bitstream does not conform to the video coding standard when at least one of: a chroma-related constraint flag is equal to 0 and when there are no chroma components for pictures in the bitstream, or an inter prediction-related constraint flag is equal to 0 when all slices of the bitstream are I slices.

Abstract: Techniques are described for video encoding and decoding using reference picture resampling with switchable filters. One example involves obtaining a current picture and a reference picture, identifying filter index information for a current block of the current picture, and determining that a first picture size value of the current picture and a second picture size value of the reference picture are different. Based on the determining that the first picture size value of the current picture and the second picture size value of the reference picture are different, performing a resampling process using a default filter index in place of a current filter index identified by the filter index information. Additional examples can use the current filter index identified by the filter index information in subsequent blocks. In various examples, the current filter index can be derived or signaled.

Abstract: A video decoder may be configured to output layers of video data according to layers specified in an output layer set mode as well as based on the actual layers received in an access unit. Accordingly, the video coder may be configured to output layers actually received rather than restart a video bitstream in situations where the layers actually received do not match the layers specified in the output layer set mode. In another example, a video encoder may disable inter prediction when the sub-picture ID of a sub-picture in a currently coded picture does not match the sub-picture ID of a sub-picture in a reference picture.

Abstract: As part of bypass decoding syntax elements for a set of coefficients in response to reaching a maximum number of regular coded bins, a video decoder is configured to receive a prefix value for a transform coefficient; decode the prefix value using Golomb-Rice coding; in response to a length of the prefix value being equal to a threshold value, receive a suffix value for the transform coefficient; decode the suffix value using exponential Golomb coding; and determine a level value for the transform coefficient based on the decoded prefix value and the decoded suffix value.

Abstract: A video encoder may transform residual data by using a transform selected from a group of transforms. The transform is applied to the residual data to create a two-dimensional array of transform coefficients. A scanning mode is selected to scan the transform coefficients in the two-dimensional array into a one-dimensional array of transform coefficients. The combination of transform and scanning mode may be selected from a subset of combinations that is based on an intra-prediction mode. The scanning mode may also be selected based on the transform used to create the two-dimensional array. The transforms and/or scanning modes used may be signaled to a video decoder.

Abstract: A video decoder may be configured to receive, in response to receiving a first syntax element indicating that reference picture list information is included in a picture header syntax structure, a second syntax element in the picture header syntax structure indicating whether a collocated picture used for temporal motion vector prediction is to be derived from a first reference picture list or a second reference picture list; receive a slice of the video data that refers to the picture header syntax structure; and in response to the slice being a P slice, set a value for a third syntax element associated with the slice to a first value for the third syntax element, with the first value for the third syntax element indicating that the collocated picture used for temporal motion vector prediction is to be derived from the first reference picture list.

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.

Abstract: A video decoder can be configured to determine that a first subpicture of a current picture has associated scaling parameters; receive the associated scaling parameters for the first subpicture of the current picture in response to determining that the first subpicture of the current picture has the associated scaling parameters; determine motion information, for a block of the first subpicture of the current picture, that identifies a subpicture of a reference picture; locate a prediction block for the block of the first subpicture of the current picture in the subpicture of the reference picture; and scale the prediction block based on the associated scaling parameters for the first subpicture of the current picture.

Abstract: As part of bypass decoding syntax elements for a set of coefficients in response to reaching a maximum number of regular coded bins, a video decoder is configured to receive a prefix value for a transform coefficient; decode the prefix value using Golomb-Rice coding; in response to a length of the prefix value being equal to a threshold value, receive a suffix value for the transform coefficient; decode the suffix value using exponential Golomb coding; and determine a level value for the transform coefficient based on the decoded prefix value and the decoded suffix value.

Abstract: Systems and techniques are described herein for processing video data using a neural network system. For instance, a process can include generating, by a first convolutional layer of an encoder sub-network of the neural network system, output values associated with a luminance channel of a frame. The process can include generating, by a second convolutional layer of the encoder sub-network, output values associated with at least one chrominance channel of the frame. The process can include generating a combined representation of the frame by combining the output values associated with the luminance channel of the frame and the output values associated with the at least one chrominance channel of the frame. The process can include generating encoded video data based on the combined representation of the frame.

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 size of a current block of video data; determine an intra-prediction mode for the current block of video data; determine a mode group including the determined intra-prediction mode, the mode group being one of a plurality of mode groups, each including respective sets of intra-prediction modes; determine a set of available multiple transform selection (MTS) schemes for the current block according to the size and the intra-prediction mode for the current block; determine an MTS scheme from the set of available MTS schemes according to the determined mode group; apply transforms of the MTS scheme to a transform block of the current block to produce a residual block for the current block; and decode the current block using the residual block.

Abstract: A method of decoding video data includes determining an intra prediction mode from a plurality of intra prediction modes for a current block of the video data, determining a low frequency non-separable transform (LFNST) kernel from a plurality of LFNST kernels for the current block based on the determined intra prediction mode, wherein at least one LFNST kernel of the plurality of LFNST kernels is associated with at least two different intra prediction modes of the plurality of intra prediction modes, applying an inverse of the determined LFNST kernel to coefficient values generated from a transform unit (TU) of the current block to generate intermediate values, applying an inverse primary transform on the intermediate values to generate residual data, and reconstructing the current block based on the residual data.

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 for decoding video data includes a memory configured to store video data; and one or more processors implemented in circuitry and configured to: determine that a transform block of video data has a size of 8×8 coefficients and that the transform block is transformed using a low-frequency non-separable transform (LFNST); decode at least nine non-zero transform coefficients of the transform block; inverse transform the transform block using an inverse LFNST to reproduce a residual block corresponding to the transform block; and reconstruct a block of the video data using the residual block.

Abstract: Video encoders and video decoders are configured to supplemental enhancement information (SEI) messages. The SEI messages may include picture orientation transform type syntax elements that indicate how a picture may be rotated and/or mirrored. The SEI messages may also include quality metrics.

Abstract: Video encoders and video decoders are configured to supplemental enhancement information (SEI) messages. The SEI messages may include picture orientation transform type syntax elements that indicate how a picture may be rotated and/or mirrored. The SEI messages may also include quality metrics.