Abstract: Provided is a video decoding method including: obtaining a first motion vector indicating a first reference block of a current block in a first reference picture and a second motion vector indicating a second reference block of the current block in a second reference picture; obtaining a parameter related to pixel group unit motion compensation of the current block, based on at least one of information of the parameter related to the pixel group unit motion compensation and a parameter related to an image including the current picture; generating a prediction block by performing, with respect to the current block, block unit motion compensation based on the first motion vector and the second motion vector and performing the pixel group unit motion compensation based on the parameter related to the pixel group unit motion compensation; and reconstructing the current block. Here, a pixel group may include at least one pixel.

Abstract: Entropy coding, such as multi-symbol arithmetic coding, is used in video compression to encode data into a compressed bit stream for transmission. Some entropy coding techniques are adaptive, meaning that the probability distribution is updated on the fly, based on the data. Accuracy of cumulative probability estimation in adaptive multi-symbol arithmetic coding can impact coding efficiency. To address the issue, a mixture of two or more adaptive cumulative probability estimations computed using two or more adaptation parameters can be used in place of a single cumulative probability estimate. The two or more adaptation parameters can be unique for a context model. A divergence in the adaptive cumulative probability estimations may signal a sudden change in the probability of a symbol. The divergence may trigger a reset of one or more adaptive cumulative probability estimations.

Abstract: Provided is a video decoding method including: obtaining a first motion vector indicating a first reference block of a current block in a first reference picture and a second motion vector indicating a second reference block of the current block in a second reference picture; obtaining a parameter related to pixel group unit motion compensation of the current block, based on at least one of information of the parameter related to the pixel group unit motion compensation and a parameter related to an image including the current picture; generating a prediction block by performing, with respect to the current block, block unit motion compensation based on the first motion vector and the second motion vector and performing the pixel group unit motion compensation based on the parameter related to the pixel group unit motion compensation; and reconstructing the current block. Here, a pixel group may include at least one pixel.

Abstract: Provided is a video decoding method including: determining an inter prediction mode of a current block when the current block is inter-predicted; determining at least one reference sample location to be referred to by the current block, based on the inter prediction mode of the current block; determining filter information to be applied to at least one reconstructed reference sample corresponding to the at least one reference sample location, based on the inter prediction mode of the current block; performing filtering on the at least one reconstructed reference sample, based on the filter information; and decoding the current block by using prediction samples generated via the filtering.

Abstract: Provided is a video decoding method including: determining an inter prediction mode of a current block when the current block is inter-predicted; determining at least one reference sample location to be referred to by the current block, based on the inter prediction mode of the current block; determining filter information to be applied to at least one reconstructed reference sample corresponding to the at least one reference sample location, based on the inter prediction mode of the current block; performing filtering on the at least one reconstructed reference sample, based on the filter information; and decoding the current block by using prediction samples generated via the filtering.

Abstract: Provided is a video decoding method including: determining an inter prediction mode of a current block when the current block is inter-predicted; determining at least one reference sample location to be referred to by the current block, based on the inter prediction mode of the current block; determining filter information to be applied to at least one reconstructed reference sample corresponding to the at least one reference sample location, based on the inter prediction mode of the current block; performing filtering on the at least one reconstructed reference sample, based on the filter information; and decoding the current block by using prediction samples generated via the filtering.

Abstract: An image decoding method and apparatus according to an embodiment may extract, from a bitstream, a quantization coefficient generated through core transformation, secondary transformation, and quantization; generate an inverse-quantization coefficient by performing inverse quantization on the quantization coefficient; generate a secondary inverse-transformation coefficient by performing secondary inverse-transformation on a low frequency component of the inverse-quantization coefficient, the secondary inverse-transformation corresponding to the secondary transformation; and perform core inverse-transformation on the secondary inverse-transformation coefficient, the core inverse-transformation corresponding to the core transformation.

Abstract: Provided is a video decoding method including determining a displacement vector per unit time of pixels of a current block in a horizontal direction or a vertical direction, the pixels including a pixel adjacent to an inside of a boundary of the current block, by using values about reference pixels included in a first reference block and a second reference block, without using a stored value about a pixel located outside boundaries of the first reference block and the second reference block; and obtaining a prediction block of the current block by performing block-unit motion compensation and pixel group unit motion compensation on the current block by using a gradient value in the horizontal direction or the vertical direction of a first corresponding reference pixel in the first reference block which corresponds to a current pixel included in a current pixel group in the current block, a gradient value in the horizontal direction or the vertical direction of a second corresponding reference pixel in the sec

Abstract: An image decoding method and apparatus according to an embodiment may extract, from a bitstream, a quantization coefficient generated through core transformation, secondary transformation, and quantization; generate an inverse-quantization coefficient by performing inverse quantization on the quantization coefficient; generate a secondary inverse-transformation coefficient by performing secondary inverse-transformation on a low frequency component of the inverse-quantization coefficient, the secondary inverse-transformation corresponding to the secondary transformation; and perform core inverse-transformation on the secondary inverse-transformation coefficient, the core inverse-transformation corresponding to the core transformation.

Abstract: Provided is a video decoding method including: obtaining a first motion vector indicating a first reference block of a current block in a first reference picture and a second motion vector indicating a second reference block of the current block in a second reference picture; obtaining a parameter related to pixel group unit motion compensation of the current block, based on at least one of information of the parameter related to the pixel group unit motion compensation and a parameter related to an image including the current picture; generating a prediction block by performing, with respect to the current block, block unit motion compensation based on the first motion vector and the second motion vector and performing the pixel group unit motion compensation based on the parameter related to the pixel group unit motion compensation; and reconstructing the current block. Here, a pixel group may include at least one pixel.

Abstract: Provided is a video decoding method including determining a displacement vector per unit time of pixels of a current block in a horizontal direction or a vertical direction, the pixels including a pixel adjacent to an inside of a boundary of the current block, by using values about reference pixels included in a first reference block and a second reference block, without using a stored value about a pixel located outside boundaries of the first reference block and the second reference block; and obtaining a prediction block of the current block by performing block-unit motion compensation and pixel group unit motion compensation on the current block by using a gradient value in the horizontal direction or the vertical direction of a first corresponding reference pixel in the first reference block which corresponds to a current pixel included in a current pixel group in the current block, a gradient value in the horizontal direction or the vertical direction of a second corresponding reference pixel in the sec

Abstract: Provided is a video decoding method including: obtaining a first motion vector indicating a first reference block of a current block in a first reference picture and a second motion vector indicating a second reference block of the current block in a second reference picture; obtaining a parameter related to pixel group unit motion compensation of the current block, based on at least one of information of the parameter related to the pixel group unit motion compensation and a parameter related to an image including the current picture; generating a prediction block by performing, with respect to the current block, block unit motion compensation based on the first motion vector and the second motion vector and performing the pixel group unit motion compensation based on the parameter related to the pixel group unit motion compensation; and reconstructing the current block. Here, a pixel group may include at least one pixel.

Abstract: An image decoding method and apparatus according to an embodiment may extract, from a bitstream, a quantization coefficient generated through core transformation, secondary transformation, and quantization; generate an inverse-quantization coefficient by performing inverse quantization on the quantization coefficient; generate a secondary inverse-transformation coefficient by performing secondary inverse-transformation on a low frequency component of the inverse-quantization coefficient, the secondary inverse-transformation corresponding to the secondary transformation; and perform core inverse-transformation on the secondary inverse-transformation coefficient, the core inverse-transformation corresponding to the core transformation.

Abstract: An embodiment of a video codec may include technology to store video data, and utilize a generalized bypass bin to one or more of encode and decode the video data. Other embodiments are disclosed and claimed.

Abstract: Methods, apparatus, systems, and articles of manufacture are disclosed for multi-symbol equiprobable mode entropy coding. An example apparatus includes equiprobable bypass control circuitry to determine whether an input value associated with the one or more blocks is greater than a reference value. The example apparatus also includes interval control circuitry to, based on the determination, adjust at least one of an upper limit or a lower limit based on an approximate value approximating a product of (1) a quotient of (a) a difference between the alphabet size and one and (b) the alphabet size and (2) the upper limit, the upper limit and the lower limit forming a range of values within which the input value is to be encoded.

Abstract: Provided is a video decoding method including: obtaining correlation information of a luma value and a chroma value from a most probable chroma (MPC) mode reference region of a current chroma block; determining a prediction value of a chroma sample of the current chroma block from luma samples of a current luma block corresponding to the current chroma block, according to the correlation information; and decoding the current chroma block based on the prediction value of the chroma sample.

Abstract: A video decoding and video encoding method of performing inter prediction in a bi-directional motion prediction mode, in which a prediction pixel value of a current block may be generated by not only using a pixel value of a first reference block of a first reference picture and a pixel value of a second reference block of a second reference picture, but also using a first gradient value of the first reference block and a second gradient value of the second reference block, in a bi-directional motion prediction mode. Accordingly, encoding and decoding efficiency may be increased since a prediction block similar to an original block may be generated.

Abstract: Provided are a method and apparatus for performing transformation and inverse transformation on a chroma block by using a variable transform kernel, during video encoding and decoding processes. A video decoding method includes: obtaining, from a bitstream, chroma multi-transform kernel information indicating whether a chroma transform kernel for inverse transformation of a chroma block is determined to be among a plurality of chroma transform kernels; while determining whether the chroma transform kernel is determined to be among the plurality of chroma transform kernels according to the chroma multi-transform kernel information, determining whether to determine the chroma transform kernel by using a luma transform kernel; and performing inverse transformation on the chroma block by using the chroma transform kernel.

Abstract: A video decoding and video encoding method of performing inter prediction in a bi-directional motion prediction mode, in which a prediction pixel value of a current block may be generated by not only using a pixel value of a first reference block of a first reference picture and a pixel value of a second reference block of a second reference picture, but also using a first gradient value of the first reference block and a second gradient value of the second reference block, in a bi-directional motion prediction mode. Accordingly, encoding and decoding efficiency may be increased since a prediction block similar to an original block may be generated.

Abstract: Provided is a video decoding method including: obtaining correlation information of a luma value and a chroma value from a most probable chroma (MPC) mode reference region of a current chroma block; determining a prediction value of a chroma sample of the current chroma block from luma samples of a current luma block corresponding to the current chroma block, according to the correlation information; and decoding the current chroma block based on the prediction value of the chroma sample.