Abstract: The present invention relates to an intra prediction mode mapping method and a device using the method. The intra prediction mode includes: decoding flag information providing information regarding whether an intra prediction mode of a plurality of candidate intra prediction modes for the current block is the same as the intra prediction mode for the current block, and decoding a syntax component including information regarding the intra prediction mode for the current block in order to induce the intra prediction mode for the current block if the intra prediction mode from among the plurality of candidate intra prediction modes for the current block is not the same as the intra prediction mode for the current block. Thus, it is possible to increase the efficiency with which are images are decoded.

Abstract: A coding device and a decoding device are configured to include an estimated prediction mode deciding section (122a) including: a reference block selecting section (1223a) for selecting a reference block for use in estimating an intra-prediction mode for a subject block; an estimating number deciding section (1222a) for deciding an estimating number of estimated values to be estimated for the intra-prediction mode; and an estimated prediction mode deriving section (1221a) for estimating, based on a reference block, the estimating number of estimated values of the prediction mode.

Abstract: An image encoding/decoding method and apparatus are provided. An image decoding method performed by an image decoding apparatus may comprise parsing weight information specifying a weight for a reference sample from a bitstream according to a weight parameter syntax structure, and decoding a current block by performing inter prediction based on the weight information. The parsing according to the weight parameter syntax structure may comprise obtaining weight number information specifying the number of weight information obtained from the bitstream according to the weight parameter syntax structure and obtaining weight information from the weight parameter syntax structure based on the weight number information.

Abstract: A video decoding method includes: determining a usage of an SVT-vertical (V) or an SVT-horizontal (H) for a residual block; determining a transform block position of a transform block of the residual block; determining a transform type of the transform block, wherein the transform type indicates a horizontal transform and a vertical transform for the transform block, wherein at least one of the horizontal transform or the vertical transform is a discrete sine transform (DST)-7; and reconstructing the residual block based on the transform type, the transform block position, and transform coefficients of the transform block.

Abstract: Devices, systems and methods related to digital video coding, and specifically, to signaling of slice types in video picture headers are described. One example method of video processing includes performing a conversion between a video including one or more video pictures including one or more slices and a bitstream of the video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies that for a video picture of the one or more video pictures having all slices coded as I slices, P slice and B slice related syntax elements are omitted from a picture header for the video picture.

Abstract: Block-based, low latency rate control for an encoding system in which a wavelet transform decomposes pixel blocks into subbands stored as subbands in wavelet blocks (WBs) for encoding. Quantization parameters (QPs) for the subbands in each WB are estimated using a method that minimizes wavelet-inverse distortion given a rate bound. For each subband, a rate curve is generated based on an unquantized DCT histogram and bit count statistics for the subband, and a distortion curve is generated based on the unquantized DCT histogram and a distortion estimate for the subband that is estimated using a masked estimator. Once the rate-distortion curves for the subbands are generated, a bisection search may be used to find a point on each curve where the slope is the same for all the curves. The QPs associated with those equally sloped points are the global minimizing QPs for the wavelet block.

Abstract: An approach for encoding/decoding video data including obtaining video data; parsing the obtained video data to obtain partitioning parameters; obtaining a partitioned coding block based on the partitioning parameters; and decoding the obtained video data based on the partitioned coding block. The partitioned coding block may be partitioned into a rectangular partition and at least one non-rectangular partition.

Abstract: Disclosed according to one exemplary embodiment includes not limited to: a filtering unit configured to generate filtering information by filtering a residual image corresponding to a difference between an original image and a prediction image; an inverse filtering unit configured to generate inverse filtering information by inversely filtering the filtering information; an estimator configured to generate the prediction image based on the original image and reconstruction information; a CNN-based in-loop filter configured to receive the inverse filtering information and the prediction image and to output the reconstruction information; and an encoder configured to perform encoding based on the filtering information and information of the prediction image, and wherein the CNN-based in-loop filter is trained for each of the plurality of artefact sections according to an artefact value or for each of the plurality of quantization parameter sections according to a quantization parameter.

Abstract: An image decoding method according to the present invention can comprise the steps of: acquiring residual coefficients of a current block; dequantizing the residual coefficients; performing secondary inverse transformation on the dequantized residual coefficients; and performing primary inverse transformation on the performance result of the secondary inverse transformation. The secondary inverse transformation can be performed for a partial region of the current block.

Abstract: The long filter decision in VVC is modified by adding at least one gradient check that at least includes sample p6 or q6. This makes it possible to avoid using the long filters when there is some natural structure at sample p6 or q6. In one specific embodiment at least two gradient checks including both q6 and p6 are added. In another embodiment, the dpq threshold is modified from beta>>2 to beta>>4. This threshold change embodiment may be used in conjunction with or instead of the embodiment in which a gradient check that includes p6 and/or q6 is added to the long filter decision.

Abstract: A multimedia system allocates, during encoding of a multimedia stream, bits to portions of frames based on quality metrics and bit usages for different quantization parameters (QPs). An encoder of the multimedia system encodes a frame in a first pass with a first QP and in a second pass with a second QP. A comparator of the multimedia system measures and compares quality metrics, such as mean squared error, for each portion of the frame encoded with the first QP and the second QP. The comparator compares the difference between the quality metrics for each portion encoded with each QP to a threshold. If the difference in quality metrics for a portion exceeds the threshold, the comparator selects the portion for inclusion in a subset of portions to be encoded with the second QP.

Abstract: Provided are a video decoding method and apparatus and a video encoding method and apparatus which determine whether to use a Most Probable Mode (MPM) list, based on encoding information of a current block, obtain, from a bitstream, intra prediction mode index information indicating one of candidate intra prediction modes included in the MPM list, and determine an intra prediction mode of the current block by using the obtained intra prediction mode index information.

Abstract: An image encoder performs a first partitioning including using a first partition mode, without writing first splitting information indicative of the first partition mode into a bitstream, to split a first block into a plurality of second blocks in response to that the first block is located adjacent to an edge of a picture and that the dimensions of the first block satisfy a first condition; and performs a second partitioning on the second block by writing second splitting information indicative of a second partition mode into the bitstream, wherein the second partition mode allows at least one of a quad tree splitting and a binary splitting, and using the second partition mode to split the second block into a plurality of coding units (CUs), wherein the second partition mode prohibits the quad tree splitting of the second block in certain conditions.

Abstract: Various schemes pertaining to pre-encoding processing of a video stream with motion compensated temporal filtering (MCTF) are described. An apparatus determines a filtering interval for a received raw video stream having pictures in a temporal sequence. The apparatus selects from the pictures a plurality of target pictures based on the filtering interval, as well as a group of reference pictures for each target picture to perform pixel-based MCTF, which generates a corresponding filtered picture for each target picture. The apparatus subsequently transmits the filtered pictures as well as non-target pictures to an encoder for encoding the video stream. Subpictures of natural images and screen content images are separately processed by the apparatus.

Abstract: Devices, systems and methods related to digital video coding, and specifically, to signaling of slice types in video picture headers are described. One example method of video processing includes performing a conversion between a video including one or more video pictures including one or more slices and a bitstream of the video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies that for a video picture of the one or more video pictures having all slices coded as I slices, P slice and B slice related syntax elements are omitted from a picture header for the video picture.

Abstract: Methods, systems and apparatus for video processing are described. One example video processing method includes performing a conversion between a video including a video block and a bitstream of the video according to a rule, wherein the rule specifies whether to include, in a slice header (SH), a first syntax element that indicates whether a transform skip based residual coding is disabled for a slice, and wherein the rule specifies that whether to include the first syntax element in the SH is selectively based on a second syntax element in a sequence parameter set (SPS) that indicates whether a TS mode is enabled for the video block.

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: An encoder includes circuitry and memory connected to the circuitry. In operation, the circuitry: stores MV information and correction processing information into a FIFO buffer for an HMVP mode in association, the MV information being derived for a processed block and correction processing information being related to correction processing of a prediction image of the processed block; registers, in a prediction candidate list for a merge mode, one or more prediction candidates each being a combination of MV information and correction processing information, the prediction candidates including a prediction candidate which is a combination of the motion vector information and the correction processing information stored in the FIFO buffer; and selects a prediction candidate from the prediction candidate list when a current block is to be processed in the merge mode, and performs correction processing of a prediction image of the current block, based on the correction processing information.

Abstract: Provided is a video decoding method including: determining a prediction mode of a current block to be one of a skip mode and a merge mode; when a motion vector, which is determined from a merge candidate list of the current block, and a merge motion vector difference are to be used, obtaining merge candidate information indicating one candidate in the merge candidate list by performing entropy encoding on a bitstream by applying one piece of context information; determining a base motion vector from one candidate determined from the merge candidate list, based on the merge candidate information; and determining a motion vector of the current block by using a distance index of a merge motion vector difference of the current block and a direction index of the merge motion vector difference to use the base motion vector and the merge motion vector difference.

Abstract: The entropy coding of a current part of a predetermined entropy slice is based on, not only, the respective probability estimations of the predetermined entropy slice as adapted using the previously coded part of the predetermined entropy slice, but also probability estimations as used in the entropy coding of a spatially neighboring, in entropy slice order preceding entropy slice at a neighboring part thereof. Thereby, the probability estimations used in entropy coding are adapted to the actual symbol statistics more closely, thereby lowering the coding efficiency decrease normally caused by lower-delay concepts. Temporal interrelationships are exploited additionally or alternatively.