Abstract: Embodiments include a picture reconstruction method and apparatus for a video picture. The picture reconstruction method includes: obtaining a prediction mode of a current coding unit, and/or obtaining a prediction partition mode of the current coding unit, where the current coding unit includes a luma coding block and a chroma coding block, and the prediction partition mode is a mode of splitting the current coding unit into prediction blocks or prediction units; obtaining a transform block of the current coding unit based on the prediction partition mode and/or the prediction mode; and generating a reconstructed picture block of the current coding unit based on the transform block. According to the method in the embodiments, video coding efficiency can be improved.

Abstract: This disclosure provides an image encoding method and apparatus and an image decoding method and apparatus. For a to-be-encoded image in a to-be-encoded video sequence, a reference image may be selected from at least one knowledge-base image in a knowledge-base image set. In addition, bitstream data of the to-be-encoded image includes identification information used to identify the reference image of the to-be-encoded image.

Abstract: An intra prediction method by using cross component liner prediction mode (CCLM), includes: determining a luma block corresponding to a current chroma block; obtaining luma reference samples of the luma block based on determining L available chroma reference samples of the current chroma block, wherein the obtained luma reference samples of the luma block are down-sampled luma reference samples; calculating linear model coefficients based on the luma reference samples and chroma reference samples that correspond to the luma reference samples; and obtaining a prediction for the current chroma block based on the linear model coefficients and values of a down-sampled luma block of the luma block.

Abstract: This application provides a weighted prediction method for multi-hypothesis encoding and an apparatus. The method includes: determining a first target prediction block of a to-be-processed picture block based on an inter prediction mode; determining a second target prediction block of the to-be-processed picture block based on an intra prediction mode; determining, based on indication information in a bitstream, weight coefficients respectively corresponding to the inter prediction mode and the intra prediction mode; and weighting a pixel value of the first target prediction block and a pixel value of the second target prediction block based on the weight coefficients, to obtain a prediction value of the to-be-processed picture block. Implementation of this application improves prediction accuracy of a pixel value of a picture block and encoding/decoding performance to some extent.

Abstract: A video decoding method includes parsing a bitstream to obtain a split mode to transform units (TUs) in a current coding unit (CU). Each of the TUs has a serial number in a one-to-one correspondence with positions of the TUs in the current CU. A transform coefficient of a luminance transform block of a current TU in the TUs is obtained. A transform type of the luminance transform block of the current TU is obtained based on the split mode and a serial number of the current TU. An inverse transform on the transform coefficient of the luminance transform block of the current TU is performed based on the transform type of the luminance transform block of the current TU to obtain a reconstructed residual of the luminance transform block of the current TU. A reconstructed block of the current CU is obtained based on the reconstructed residual.

Abstract: A video coding mechanism is disclosed. The mechanism includes obtaining a coding tree unit including luma samples and chroma samples. The mechanism partitions the luma samples and the chroma samples according to a common coding tree when a size of a first coding tree node exceeds a threshold. The mechanism also partitions the luma samples with a luma coding sub-tree when a size of a second coding tree node is equal to or less than the threshold. The mechanism also chroma samples with a chroma coding sub-tree when a size of a third coding tree node is equal to or less than the threshold. The luma coding sub-tree contains a different set of split modes than the chroma coding sub-tree.

Abstract: A video coding mechanism is disclosed. The mechanism includes selecting a split mechanism to split a coding unit (CU) into sub-CUs for application of one or more transform units (TUs), the selection of the split mechanism based on comparing a CU width to a max TU width and comparing a CU height to a max TU height. The selected split mechanism is applied to the CU to obtain sub-CUs. A residual of one of the sub-CUs is determined. The residual includes a difference between sample values for the sub-CU and prediction samples for the sub-CU. The TUs are applied to transform the residual of the CU based on results of the selected split mechanism. A transformed residual for the CU is encoded into a bitstream.

Abstract: An encoding and decoding method, where the decoding method includes obtaining first information of a coding tree unit (CTU) in a to-be-decoded picture from a bitstream, where the first information indicates an allowed value range of a width-to-height ratio of a coding unit (CU) obtained by dividing the CTU, obtaining division information of the CTU from the bitstream, dividing the CTU into one or more CUs based on the first information and the division information, where a width-to-height ratio of the one or more CUs falls within the value range indicated by the first information, and the plurality of CUs do not overlap each other, and decoding the one or more CUs to obtain a reconstructed pixel of the one or more CUs.

Abstract: A picture prediction method includes receiving a bitstream, parsing the bitstream to obtain a prediction mode of a current block, when the prediction mode of the current block is a combined intra and inter prediction mode, selecting an execution manner of a triangular prediction unit mode according to a preset policy, determining motion information of the current block according to the execution manner of the triangular prediction unit mode, performing a motion compensation process based on the motion information, to obtain an inter prediction sample, obtaining an intra prediction sample according to the prediction mode of the current block, and combining the inter prediction sample and the intra prediction sample to obtain a prediction picture of the current block.

Abstract: A video decoding method, including: parsing a received bitstream to obtain prediction information of a coding unit (CU); obtaining a target transform mode of a residual transform unit (TU); parsing the received bitstream to obtain transform coefficients of the residual TU; applying an inverse quantization to the transform coefficients of the residual TU to obtain dequantized coefficients; applying, based on the target transform mode, an inverse transform to the dequantized coefficients to obtain a residual block of the residual TU; obtaining a prediction block of the CU based on the prediction information; obtaining a video block based on the residual block and the prediction block; and outputting a video sequence including a video frame that includes the video block.

Abstract: A method for inverse quantization of a current block of a picture is provided. The method is performed by a decoder, and the picture comprises a luminance component and a chrominance component, where the luminance component and the chrominance component are partitioned into multiple blocks. The method includes obtaining one or more existing quantization parameter (QP) values from a received bitstream, wherein the one or more existing QP values are associated with a current block in the chrominance component; determining a QP value for the current block in the chrominance component based on the one or more existing QP values; performing inverse quantization on the current block in the chrominance component using the determined QP value.

Abstract: This application provides an example method for processing video or image data. The method includes obtaining a non-overlapped region. The method also includes obtaining a transform block (TB) corresponding to a coding block. The method further includes determining whether the TB cross a border of the non-overlapped region or not. The method also includes, if the TB cross a border of the non-overlapped region, splitting the TB to obtain at least two sub-TBs according to the border of the non-overlapped region.

Abstract: The present disclosure discloses a video decoding method and a video decoder. The method includes: parsing coding tree split information to obtain a current node; determining coordinates of an upper-left corner of a region covered by a current quantization group based on a depth N of the current node; obtaining a QP delta of a current CU in the region covered by the current quantization group; and obtaining a reconstructed picture of the current CU based on the QP delta of the current CU.

Abstract: Inter prediction method and apparatus are disclosed to resolve problems in the conventional technology that prediction samples obtained in an inter prediction mode are spatially discontinuous, prediction efficiency is affected, and prediction residual energy is relatively high. The method includes: parsing a bitstream to obtain motion information of a to-be-processed picture block; performing motion compensation on the to-be-processed picture block based on the obtained motion information, to obtain a prediction block of the to-be-processed picture block, where the prediction block of the to-be-processed picture block includes a prediction value of a target sample; and performing weighting calculation on one or more reconstructed values of one or more reference samples and the prediction value of the target sample, to update the prediction value of the target sample, where the reference sample(s) have a preset spatial position relationship with the target sample.

Abstract: A picture partitioning method and apparatus are described. The method includes determining a split mode of a current node, where the current node includes a luma block and a chroma block. The method further includes determining, based on the split mode of the current node and a size of the current node, that the chroma block of the current node is not further split. In accordance with the chroma block of the current node not being further split, the method includes splitting the luma block of the current node based on the split mode of the current node. In accordance with the chroma block of the current node not being further split, the method may be used to split only the luma block of the current node, thereby improving encoding and decoding efficiency, reducing a maximum throughput of a codec, and facilitating implementation of the codec.

Abstract: A picture encoding/decoding method and a related apparatus are provided. The picture decoding method includes obtaining a current picture; selecting, from a knowledge base, K reference pictures of the current picture, where at least one picture in the knowledge base does not belong to a random access segment in which the current picture is located and wherein K is an integer greater than or equal to 1; and decoding the current picture according to the K reference pictures.

Abstract: The present disclosure discloses a video decoding method, including: parsing a received bitstream to obtain prediction information of a CU; obtaining a target transform mode of a residual TU; parsing the received bitstream to obtain transform coefficients of the residual TU; applying an inverse quantization to the transform coefficients of the residual TU to obtain dequantized coefficients; applying, based on the target transform mode, an inverse transform to the dequantized coefficients to obtain a residual block of the residual TU; obtaining a prediction block of the CU based on the prediction information; and obtaining a video block based on the residual block and the prediction block; and outputting a video sequence, the video sequence including a video frame that includes the video block.

Abstract: Techniques are described of a linear model prediction mode. A set of reconstructed neighboring luma samples are determined. Two pairs of luma value and chroma value are determined according to N reconstructed neighboring luma samples, N reconstructed neighboring chroma samples, M reconstructed neighboring luma samples, and M reconstructed neighboring chroma samples. The minimum value of the N reconstructed neighboring luma samples is not less than the maximum luma value of the remaining reconstructed neighboring luma samples of the set of reconstructed neighboring luma samples. The maximum value of the M reconstructed neighboring luma samples is not larger than the minimum luma value of the remaining reconstructed neighboring luma samples of the set of reconstructed neighboring luma samples. M>1 and N>1. Linear model parameters are determined based on the two pairs of luma value and chroma value, and a predictive block is determined based on the linear model parameters.

Abstract: A video coding mechanism is disclosed. The mechanism includes partitioning an image to create at least one coding tree unit (CTU) with at least one coding tree node. The mechanism further includes determining that the coding tree node height is twice a maximum transform unit (TU) height and the coding tree node width is twice a maximum TU width. The mechanism further includes selecting a split mode for the coding tree node based on the determination. The split mode is selected from a quad-tree split, a horizontal binary-tree split, and no split. The mechanism further includes applying the split mode to the coding tree node to create one or more coding units (CUs). The mechanism further includes encoding the CUs into a bitstream. The mechanism further includes transmitting the bitstream toward a decoder.

Abstract: This application provides a method for determining a coding tree node split mode and a coding device. The method includes the step of determining a non-split based coding cost for coding a current image area corresponding to the current node and determining a binary tree split based coding cost for coding the current image area. The method further includes determining, based on the non-split based coding cost and the binary tree split based coding cost, whether a triple tree split based coding cost for coding the current image area needs to be obtained. If the triple tree split based coding cost needs to be obtained, a triple tree split is performed on the current node. The method then determines a split mode of the current node that corresponds to a minimum coding cost.