A coding method encodes an image by dividing the image into blocks, and comprises: dividing a coding target image into a plurality of coding unit blocks; determining whether or not to encode by dividing the coding unit block into a plurality of sub-coding unit blocks, on a basis of an edge direction and an edge strength of an edge obtained for each pixel in the coding unit block; and encoding, in a case of determining to divide the coding unit block into a plurality of sub-coding unit blocks in the determining step, a first sub-coding unit block by referencing a second sub-coding unit block inside the same coding unit block as the first sub-coding unit block.

A coding method encodes an image by dividing the image into blocks, and comprises: dividing a coding target image into a plurality of coding unit blocks; determining whether or not to encode by dividing the coding unit block into a plurality of sub-coding unit blocks, on a basis of an edge direction and an edge strength of an edge obtained for each pixel in the coding unit block; and encoding, in a case of determining to divide the coding unit block into a plurality of sub-coding unit blocks in the determining step, a first sub-coding unit block by referencing a second sub-coding unit block inside the same coding unit block as the first sub-coding unit block.

An image encoding method for encoding an image includes: a prediction image generation step of generating a synthesis-prediction image by performing synthesis processing of synthesizing an inter-prediction image and an intra-prediction image to an encoding-target block; and an encoding step of encoding a difference between the prediction image generated in the prediction image generation step and a pixel value of an image of the encoding-target block, the synthesis processing includes weighting processing performed to the inter-prediction image and the intra-prediction image, a weighting parameter in the weighting processing is determined in accordance with a type of the intra prediction of the encoding-target block and a combination of prediction modes of a plurality of adjacent blocks adjacent to the encoding-target block, and types of the intra prediction of the encoding-target block include a matrix weighting intra prediction.

An image encoding method for encoding an image includes: a prediction image generation step of generating a synthesis-prediction image by performing synthesis processing of synthesizing an inter-prediction image and an intra-prediction image to an encoding-target block; and an encoding step of encoding a difference between the prediction image generated in the prediction image generation step and a pixel value of an image of the encoding-target block, the synthesis processing includes weighting processing performed to the inter-prediction image and the intra-prediction image, a weighting parameter in the weighting processing is determined in accordance with a type of the intra prediction of the encoding-target block and a combination of prediction modes of a plurality of adjacent blocks adjacent to the encoding-target block, and types of the intra prediction of the encoding-target block include a matrix weighting intra prediction.

An image encoding method for encoding an image includes: a prediction image generation step of generating a prediction image of a synthesis prediction by performing synthesis processing of synthesizing a prediction image of an in-screen block copy prediction and a prediction image of an intra prediction different from the in-screen block copy prediction, to an encoding-target block; and an encoding step of encoding a difference between the prediction image generated in the prediction image generation step and a pixel value of an image of the encoding-target block, the synthesis processing includes weighting processing performed to the prediction image of the in-screen block copy prediction and the prediction image of the intra prediction that is different from the in-screen block copy prediction, and a weighting parameter of the prediction image of the intra prediction in the weighting processing is determined by information of an adjacent block adjacent to the encoding-target block.

An image encoding method for encoding an image includes: a prediction image generation step of generating a prediction image of a synthesis prediction by performing synthesis processing of synthesizing a prediction image of an in-screen block copy prediction and a prediction image of an intra prediction different from the in-screen block copy prediction, to an encoding-target block; and an encoding step of encoding a difference between the prediction image generated in the prediction image generation step and a pixel value of an image of the encoding-target block, the synthesis processing includes weighting processing performed to the prediction image of the in-screen block copy prediction and the prediction image of the intra prediction that is different from the in-screen block copy prediction, and a weighting parameter of the prediction image of the intra prediction in the weighting processing is determined by information of an adjacent block adjacent to the encoding-target block.

A method implemented by a video coding apparatus includes applying a neural network (NN) filter to an unfiltered sample of a video unit to generate a filtered sample, where the NN filter is based on a first NN filter model having a first depth, or a second NN filter model having a second depth, where the depth comprises a number of residual blocks of the respective NN filter model, and where the second depth is different than the first depth. The method also includes performing a conversion between a video media file and a bitstream based on the filtered sample.

A picture prediction method is provided, which includes: obtaining initial motion information of a current picture block; determining, based on a matching cost criterion, that positions of a pair of reference blocks are a position of a target forward reference block of the current picture block and a position of a target backward reference block of the current picture block, where positions of each pair of reference blocks include a position of a forward reference block and a position of a backward reference block; and for the positions of each pair of reference blocks, a first position offset and a second position offset are in a mirror relationship; and obtaining a predicted value of a pixel value of the current picture block based on a pixel value of the target forward reference block and a pixel value of the target backward reference block.

A picture prediction method is provided, which includes: obtaining initial motion information of a current picture block; determining, based on a matching cost criterion, that positions of a pair of reference blocks are a position of a target forward reference block of the current picture block and a position of a target backward reference block of the current picture block, where positions of each pair of reference blocks include a position of a forward reference block and a position of a backward reference block; and for the positions of each pair of reference blocks, a first position offset and a second position offset are in a mirror relationship; and obtaining a predicted value of a pixel value of the current picture block based on a pixel value of the target forward reference block and a pixel value of the target backward reference block.

A method for encoding a first stream of video data comprising a plurality of frames of video, the method, for one or more of the plurality of frames of video, comprising the steps of: encoding in a hierarchical arrangement a frame of the video data, the hierarchical arrangement comprising a base layer of video data and a first enhancement layer of video data, said first enhancement layer of video data comprising a plurality of sub-layers of enhancement data, such that when encoded: the base layer of video data comprises data which when decoded renders the frame at a first, base, level of quality; and each sub-layer of enhancement data comprises data which, when decoded with the base layer, render the frame at a higher level of quality than the base level of quality; and wherein the steps of encoding the sub-layers of enhancement data comprises: quantizing the enhancement data at a determined initial level of quantization thereby creating a set of quantized enhancement data; associating to each of the plurality of sub-layers a respective notional quantization level and allocating, for each of the plurality of sub-layers, a sub-set of the set of quantized enhancement data based on the respective notional quantization level.