A method includes receiving transform coefficients corresponding to a scaled video input signal, the scaled video input signal including a plurality of spatial layers that include a base layer. The method also includes determining a spatial rate factor based on a sample of frames from the scaled video input signal. The spatial rate factor defines a factor for bit rate allocation at each spatial layer of an encoded bit stream formed from the scaled video input signal. The spatial rate factor is represented by a difference between a rate of bits per transform coefficient of the base layer and an average rate of bits per transform coefficient. The method also includes reducing a distortion for the plurality of spatial layers by allocating a bit rate to each spatial layer based on the spatial rate factor and the sample of frames.

There is disclosed a method of encoding an input signal, the method comprising: receiving a base encoded signal, the base encoded signal being generated by feeding an encoder with a down-sampled version of an input signal; producing a first residual signal by: decoding the base encoded signal to produce a first decoded signal; and using a difference between the base decoded signal and the down-sampled version of the input signal to produce the first residual signal; producing a second residual signal by: correcting the base decoded signal using the residual signal to create a corrected decoded version; up-sampling the corrected decoded version; and using a difference between the up-sampled corrected decoded signal and the input signal to produce the second residual signal; wherein the up-sampling is one of bilinear or bicubic up-sampling. A corresponding decoding method is also disclosed.

There is disclosed a method of encoding an input signal, the method comprising: receiving a base encoded signal, the base encoded signal being generated by feeding an encoder with a down-sampled version of an input signal; producing a first residual signal by: decoding the base encoded signal to produce a first decoded signal; and using a difference between the base decoded signal and the down-sampled version of the input signal to produce the first residual signal; producing a second residual signal by: correcting the base decoded signal using the residual signal to create a corrected decoded version; up-sampling the corrected decoded version; and using a difference between the up-sampled corrected decoded signal and the input signal to produce the second residual signal; wherein the up-sampling is one of bilinear or bicubic up-sampling. A corresponding decoding method is also disclosed.

An image decoding method according to the present document comprises a step of deriving a corrected transform coefficient, wherein the step of deriving the corrected transform coefficient comprises the steps of: determining whether LFNST can be applied to the height and width of a divided sub-partition block when an ISP is applied to a current block; parsing a LFNST index when the LFNST can be applied; and deriving the corrected transform coefficient on the basis of the LFNST index and a LFNST matrix.

An image decoding apparatus capable of more preferably applying inverse non-separable transform and techniques related thereto are provided. A video decoding apparatus includes a header decoder configured to decode a flag indicating a high accuracy coding mode from a sequence parameter set SPS, a scaling processing unit configured to perform inverse quantization on a transform coefficient for each transform block, and an inverse transform processing unit configured to perform inverse transform. The scaling processing unit switches whether a variable for indicating a range of the transform coefficient depends on a bit depth or does not depend on the bit depth, based on the flag and a size of the transform block.

An image decoding apparatus capable of more preferably applying inverse non-separable transform and techniques related thereto are provided. A video decoding apparatus includes a header decoder configured to decode a flag indicating a high accuracy coding mode from a sequence parameter set SPS, a scaling processing unit configured to perform inverse quantization on a transform coefficient for each transform block, and an inverse transform processing unit configured to perform inverse transform. The scaling processing unit switches whether a variable for indicating a range of the transform coefficient depends on a bit depth or does not depend on the bit depth, based on the flag and a size of the transform block.

An image decoding method according to the present document comprises a step of applying an inverse primary transform to a transform coefficient so as to derive residual samples for a current block, wherein: the inverse primary transform is performed on the basis of an MTS index received from a bitstream; the MTS index is parsed on the basis of an effective coefficient not existing in a second area that excludes the left top first area of the current block; and the first area is a left top 16×16 area of the current block.

A filter generation method according to one embodiment is a filter generation method for generating a filter for an inter prediction image in moving image coding or video coding, wherein a computer executes a first acquisition procedure for acquiring, for each of subblocks included in a coding object block, a region in a reference image that corresponds to the subblock, a second acquisition procedure for referring to block segmentation information of the reference image and acquiring a coding block that is a block of the reference image which includes the region, and a generation procedure for generating, for the coding object block or each of a plurality of coding object blocks, an image obtained by performing an inverse transformation on one or more coding blocks each acquired in the second acquisition procedure as the filter.

A filter generation method according to one embodiment is a filter generation method for generating a filter for an inter prediction image in moving image coding or video coding, wherein a computer executes a first acquisition procedure for acquiring, for each of subblocks included in a coding object block, a region in a reference image that corresponds to the subblock, a second acquisition procedure for referring to block segmentation information of the reference image and acquiring a coding block that is a block of the reference image which includes the region, and a generation procedure for generating, for the coding object block or each of a plurality of coding object blocks, an image obtained by performing an inverse transformation on one or more coding blocks each acquired in the second acquisition procedure as the filter.

In encoding an image, a transform skip flag that is flag information indicating, for each component, whether or not to skip transform processing of transforming a residual between an image and a predicted image of the image into coefficient data is generated, the transform skip flag generated is encoded, coded data of the transform skip flag is generated, and a bit stream including the generated coded data of the transform skip flag is generated. The present encoding/decoding can be applied to, for example, an image processing device, an image encoding device, an image decoding device, a transmission device, a reception device, a transmission-reception device, an information processing device, an imaging device, a reproduction device, a bit stream generation method, a coefficient data generation method, a quantization coefficient generation method, or the like.