Sharp Kabushiki Kaisha Corporation

Fg Innovation Company Limited

Huawei Technologies Co., Limited

Dolby International Ab

Velos Media, LLC

Sharp Corporation

Yukinobu Yasugi

Tomohiro Ikai

Tomoko Aono

Tomoyuki Yamamoto

Eiichi Sasaki

Takeshi Chujoh

Takeshi Tsukuba

Tomonori Hashimoto

Takanori Yamazaki

Tianyang Zhou

Sachin G Deshpande

Yoshiya Yamamoto

Keiichiro Takada

Hiroyuki Katata

Frank Bossen

Yasuaki Tokumo

Zheming Fan

Video coding and decoding apparatuses that can enhance coding efficiency are provided. A video decoding apparatus according to an aspect of the present invention includes a parameter decoder configured to decode a transform coefficient and a coefficient sign prediction error from coded data, and a sign prediction unit configured to predict a sign of the transform coefficient. The sign prediction unit derives a cost with reference to a boundary pixel with a neighboring block for a candidate of a combination of signs of transform coefficients without sign information, selects the sign, based on the cost, and modifies the predicted transform coefficient sign, using the coefficient sign prediction error decoded by the parameter decoder. The sign prediction unit divides the transform coefficients without the sign information into multiple groups, and performs the prediction on a transform coefficient of the transform coefficients for each of the multiple groups.

Video decoding apparatus and video coding apparatus

A reference picture information decoding unit () omits decoding of a reference list sorting presence or absence flag and/or a reference list sorting order based on the number of current picture referable pictures.

Image decoding device and image coding device

In a case that a scaling value of neural network filter strength is set equal to 0, a decoded image before a deblocking filter is output, and thus block noise occurs. In a case that luma and chroma parameters are not taken into consideration, processing for an image of multiple transfer functions and chroma parameters is not appropriately performed. In a unit of a prescribed block, by using a parameter indicating a degree of application of the NN filter, an image after the deblocking filter and an image after an NN filter are combined using a different ratio of the images. Filter processing of a luma image is switched based on a luma parameter, and filter processing of a chroma image is switched based on a chroma parameter.

Video coding apparatus and video decoding apparatus

An adaptive motion vector prediction unit configured to adaptively perform spatial prediction that performs prediction using a motion vector around a target block and temporal prediction that performs prediction using a motion vector of a collocated picture is included, and in the temporal prediction performed by the adaptive motion vector prediction unit, the collocated picture to be referred to is designated on a per picture basis, and a reference list is designated on a per slice basis.

Video decoding apparatus

In a video coding and decoding method, in a case that a transmission rate is low, image quality is deteriorated due to coding distortion, but the image quality can be improved owing to post-filter processing using a neural network. However, a problem is that there may be no method of defining a strength control value to be input in the post-filter processing. A video decoding apparatus according to an aspect of the present invention includes an image decoding apparatus that generates a decoded image, and a post-filter processing apparatus that performs post-filter processing on the decoded image. In accordance with an input format for luminance and chrominance of the decoded image to be input in the post-filter processing, a strength control value obtained in a process of generating the decoded image is transformed, and the post-filter processing is performed.

Video coding apparatus and decoding apparatus

Object Known derivation, in units of intra prediction modes, of a template-based intra prediction mode based on a difference between a template prediction image and a template image has a problem that derivation of the template image and cost calculation require great computational resources. Solution An image decoding apparatus includes an intra prediction image generation unit configured to generate a template prediction image for a prescribed intra prediction mode candidate, a template cost derivation unit configured to derive a cost from the template prediction image and a template image corresponding to an image near a target block, and an intra prediction image generation unit configured to generate an intra prediction image by using a selected intra prediction mode, and a reference sample is sampled that is used to generate the template prediction image.

Image decoding apparatus and image coding apparatus

A method for signaling gradual refresh for encoding a set of pictures performed by an electronic device is provided. The method identifies a first picture in the set of pictures as being associated with a gradual refreshed picture, and stores a network abstraction layer (NAL) unit type in a coded stream associated with the first picture. The NAL unit type identifies a presence of the gradual refreshed picture. The method then stores, in the coded stream, an enable flag to identify a use of the gradual refresh for encoding at least a subset of pictures in the set of pictures.

Method and electronic device for signaling gradual decoding refresh pictures

In conventional cases that different trees are used between luma and chroma and that luma chroma prediction including multiplication in chroma intra prediction is used, there is a problem in that a processing delay caused by the chroma intra prediction is increased in small blocks. In a case that two different trees are used between luma and chroma, in a case of an 8×8 block in a luma size, 0 is derived without decoding qt_split_cu_flag, and in a case of an 8×4/4×8 block in a luma size, 0 is derived without decoding mtt_split_cu_flag. In a case that the size of a target block is smaller than a prescribed size, a chroma intra mode is derived from any one of DC, leftward prediction, and upward prediction.

Video decoding apparatus and video decoding method

Object Known derivation, on a per intra prediction modes basis, of a template-based intra mode derivation based on a difference between a template prediction image and a template image has a problem that derivation of the template image and cost calculation require great computational resources. Solution Included are an intra prediction image generation unit configured to generate a template prediction image for an intra prediction mode candidate predetermined, a template cost derivation unit configured to derive a cost from the template prediction image and a template image corresponding to an image near a target block, and an intra prediction image generation unit configured to generate an intra prediction image by using a selected intra prediction mode, wherein the number of taps of an interpolation filter for the template prediction image is less than the number of taps of an interpolation filter for intra prediction.

The amount of memory required for CCLM prediction is reduced. The CCLM prediction parameter derivation unit () derives a scale shift value corresponding to a luma difference value, and derives a CCLM prediction parameter, by shifting, by using the scale shift value, a value obtained by multiplying a value of a table referred to with a value obtained by performing right shift of the luma difference value by the scale shift value as an index and a chroma difference value. In addition, in a case of deriving a prediction image, a bit width is reduced by adaptively deriving a shift amount of a linear prediction parameter from the chroma difference value.

Prediction image generation apparatus, video decoding apparatus, video coding apparatus, and prediction image generation method

An adaptive offset filter () adds an offset to the pixel value of each pixel forming an input image. The adaptive offset filter () refers to offset-type specifying information, sets offset attributes for a subject unit area of the input image, decodes an offset having a bit width corresponding to an offset value range included in the set offset attributes, and adds the offset to the pixel value of each pixel forming the input image.

Offset decoding device, offset coding device, image filtering device

Complexity of coding/decoding of a video is reduced. An image decoding apparatus () includes a CN information decoder () configured to hierarchically split a coding node by at least any of binary tree split and ternary tree split. The CN information decoder refers to a method of splitting an immediately higher node, which is a node one generation higher than a target node, to restrict a method of splitting the target node.

Image decoding method

Object A video coding and decoding apparatus that can enhance coding efficiency is provided. Solution A video decoding apparatus includes an OOB determination unit configured to determine whether a reference block is a target of OOB processing by comparing coordinates of the reference block with coordinates of a picture, and an OOB mask derivation unit configured to derive mask data indicating whether a pixel is available by comparing coordinates of the pixel included in the reference block with the coordinates of the picture. The OOB determination unit determines whether the reference block is the target of the OOB processing based on presence or absence of processing to be applied to a reference picture including the reference block.

A moving image decoding method is provided for generating a prediction image using an intra-frame prediction mode. The moving image decoding method includes deriving a first parameter and a second parameter by using a sampled luminance value down-sampled according to a chrominance format and the intra-frame prediction mode; and deriving the prediction image by using the first parameter and the second parameter, wherein: the first parameter is derived by: deriving a logarithmic value of a luminance difference value, deriving a first value by right-shifting a second value related to the luminance difference value by the logarithmic value, and using a third value acquired by multiplying a fourth value by a chrominance difference value, wherein the fourth value is determined from a reference table by using the first value, and the second parameter is derived by using the first parameter.

Moving image decoding method using chrominance format and intra-frame prediction mode

A load in processing of searching for a motion vector is reduced. In order to solve the problem described above, a motion vector derivation apparatus according to one aspect of the present invention that derives a motion vector to be referred to for generating a prediction image to be used for coding or decoding of a video includes a motion vector search unit configured to search for a motion vector on a prediction unit basis through matching processing. The motion vector search unit is configured to stop search of the motion vector, depending on whether or not a conditional expression according to a pixel bit-depth is satisfied.

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Osaka, Japan

Yukinobu Yasugi