Disclosed herein is a video decoding method including: obtaining a transform skip mode flag indicating whether transform/inverse transform is skipped in a current block; when transform/inverse transform is skipped in the current block according to the transform skip mode flag, determining that secondary transform/inverse transform is skipped in the current block; and when transform/inverse transform is not skipped in the current block according to the transform skip mode flag, obtaining a transform matrix index for secondary transform/inverse transform of the current block and, determining whether secondary transform/inverse transform is skipped in the current block based on the transform matrix index.

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.

The present disclosure relates to an image processing device and method for enabling control of a value of a quantization parameter within a desired range.

A quantization parameter is corrected on the basis of a parameter regarding adaptive color transform and further correcting the quantization parameter on the basis of a parameter regarding transform skip, and coefficient data of an image to be encoded is quantized using a corrected quantization parameter that is the quantization parameter that has been corrected. The present disclosure 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, an electronic device, an image processing method, an information processing method, or the like.

Several techniques for video encoding and video decoding are described. One example method includes performing a conversion between a video block of a video and a bitstream of the video. The video block uses a low frequency non-separable transform for the conversion. The bitstream conforms to a format rule specifying that a syntax element is included at a syntax level for the bitstream. The syntax element is indicative of whether use of a scaling matrix which is derived from a reference scaling list is enabled for the video block. The syntax level is a sequence level, a picture level, or a slice level.

Several techniques for video encoding and video decoding are described. One example method includes performing a conversion between a video block of a video and a bitstream of the video. The video block uses a low frequency non-separable transform for the conversion. The bitstream conforms to a format rule specifying that a syntax element is included at a syntax level for the bitstream. The syntax element is indicative of whether use of a scaling matrix which is derived from a reference scaling list is enabled for the video block. The syntax level is a sequence level, a picture level, or a slice level.

A three-dimensional data encoding method includes: obtaining an attribute information item of a three-dimensional point; executing an encoding process that executes a transform process on a numerical value indicated by the attribute information item and encodes the attribute information item or that encodes the attribute information item without executing the transform process, the transform process performing at least one of scaling or offset, the scaling performing at least one of a multiplication and division operation or a shift operation, the offset performing an addition and subtraction operation; and generating a bitstream including the attribute information item encoded and a transform identification information item indicating whether the transform process has been executed.

A three-dimensional data encoding method includes: obtaining an attribute information item of a three-dimensional point; executing an encoding process that executes a transform process on a numerical value indicated by the attribute information item and encodes the attribute information item or that encodes the attribute information item without executing the transform process, the transform process performing at least one of scaling or offset, the scaling performing at least one of a multiplication and division operation or a shift operation, the offset performing an addition and subtraction operation; and generating a bitstream including the attribute information item encoded and a transform identification information item indicating whether the transform process has been executed.

A video decoding method includes performing entropy decoding processing on a code block of a video image frame of a video image frame sequence, to obtain a quantization coefficient block of residual data corresponding to the code block; collecting statistics of quantization coefficients in a target region in the quantization coefficient block, to obtain a quantization coefficient statistical value; selecting a transform matrix combination corresponding to the quantization coefficient statistical value; and performing inverse transform processing on an inverse quantization result of the quantization coefficient block based on the selected transform matrix combination, to obtain reconstructed residual data, the reconstructed residual data being used for video image reconstruction.

A video decoding method includes performing entropy decoding processing on a code block of a video image frame of a video image frame sequence, to obtain a quantization coefficient block of residual data corresponding to the code block; collecting statistics of quantization coefficients in a target region in the quantization coefficient block, to obtain a quantization coefficient statistical value; selecting a transform matrix combination corresponding to the quantization coefficient statistical value; and performing inverse transform processing on an inverse quantization result of the quantization coefficient block based on the selected transform matrix combination, to obtain reconstructed residual data, the reconstructed residual data being used for video image reconstruction.

A video decoding method according to the present invention may comprise: a step for determining whether to divide a current block into a plurality of sub-blocks; a step for determining an intra prediction mode for the current block; and a step for performing intra prediction for each sub-block on the basis of the intra prediction mode, when the current block is divided into the plurality of sub-blocks.