Sharp Kabushiki Kaisha Corporation

Fg Innovation Company Limited

Huawei Technologies Co., Limited

Dolby International Ab

Guangdong Oppo Mobile Telecommunications Corp., Ltd.

Velos Media, LLC

Sharp Corporation

Tomohiro Ikai

Yukinobu Yasugi

Tomoyuki Yamamoto

Tomoko Aono

Takeshi Tsukuba

Eiichi Sasaki

Takeshi Chujoh

Tomonori Hashimoto

Yoshiya Yamamoto

Tianyang Zhou

Takanori Yamazaki

Sachin G Deshpande

Christopher A Segall

Tadashi Uchiumi

Yasuaki Tokumo

Norio Itoh

Kiran Mukesh Misra

Jie Zhao

Seung-Hwan Kim

Keiichiro Takada

Hiroshi Watanabe

Frank Bossen

Toshio Nomura

Yoshihiro Kitaura

Toshiyuki Yoshida

Zheming Fan

Provided are an image decoding apparatus () and an image coding apparatus () in which both transform precision and residual coding efficiency are preferable. Included are a TU decoder () configured to decode, from coded data, a syntax element representing an absolute value of a transform coefficient, a scaling unit () configured to multiply a transform coefficient by a quantization-parameter dependent value and perform right-shift by a first shift value, and to perform clipping using a minimum value and a maximum value according to a first range, and an inverse conversion processing unit () configured to convert a scaled transform coefficient, perform clipping using the minimum value and the maximum value according to the first range to derive an intermediate coefficient, further transform an intermediate variable, and perform right-shift by a second shift value. The scaling unit () derives the first range, the first shift value, and the second shift value in accordance with a value of a first bit-depth, and limits the first range to be equal to or less than a prescribed value.

Image decoding apparatus and image coding apparatus

In the related art, in some cases the weighted prediction processing is performed even in a case that normal prediction processing is to be performed. A video decoding apparatus includes a weighted prediction processing unit configured to decode a weight coefficient and an offset value from coded data and to generate a prediction image by multiplying an interpolation image by the weight coefficient and adding the offset value to the interpolation image, and a normal prediction processing unit configured to generate a prediction image from the interpolation image. In a case that in the weighted prediction processing unit, a bi-prediction is performed and information of the weight coefficient and the offset value is absent for both a reference list 0 and a reference list 1, the normal prediction processing unit generates a bi-prediction image.

Video coding apparatus and video decoding apparatus

There is a problem in that implicit MTS performance is lost in a case that the implict MTS is combined with secondary transform. The present invention provides an image decoding apparatus that can more preferably apply transform by MTS and secondary transform. A video decoding apparatus includes: a second transformer configured to apply transform using a transform matrix to the transform coefficient to modify the transform coefficient in a case that secondary transform is enabled; a first transformer configured to apply separate transform including vertical transform and horizontal transform to the transform coefficient; and an implicit transform configuration unit configured to disable implicit transform in a case that the secondary transform is enabled, an intra subpartition mode is not used, and subblock transform is not used, and configured to derive a horizontal transform type according to a width of a target TU and derive a vertical transform type according to a height of the target TU in a case that the implicit transform is enabled. The first transformer performs transform according to the vertical transform type, and transform according to the horizontal transform type.

Image 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

An image decoding apparatus is implemented that can suppress a decrease in coding efficiency in a case that a high compression rate is achieved. The image decoding apparatus includes a parameter decoder, and the parameter decoder decodes a skip flag indicating whether a skip mode is applied, and in a case that the skip flag does not indicate the skip mode, decodes a merge flag indicating whether a merge mode is applied, and in a case that the merge flag does not indicate the merge mode, decodes an MMVD flag indicating whether an MMVD mode is applied.

Video 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.

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

Video coding and decoding apparatuses (and) capable of improving coding efficiency are provided. The video decoding apparatus () according to an aspect of the present invention is a video decoding apparatus () including a prediction unit () that derives a prediction image using a weight parameter derived from an angle variable, and a non-separable transform processing unit () that performs a non-separable transform, in which the non-separable transform processing unit () derives a set number (lfnstTrSetId) of the non-separable transform from split information (merge_gpm_partition_idx) of the GPM in a case that an inter-prediction mode is a GPM mode.

Video decoding apparatus and video coding apparatus

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.

An image decoding apparatus including a header decoder configured to decode, from coded data, a flag indicating whether dependent quantization is enabled and a flag prohibiting transform skip residual quantization, and a TU decoder configured to decode a transform coefficient in a TU block in an RRC mode in which a LAST position is coded, the LAST position corresponding to a decoding start position for the transform coefficient, or a TSRC mode in which the LAST position is not coded. The TU decoder performs dependent quantization in the RRC mode in a case that the transform coefficient for transform skip is decoded in the TSRC mode, and does not perform dependent quantization in the RRC mode in a case that the transform coefficient for transform skip is decoded in the RRC mode.

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

To improve a coding efficiency. There are included a PU level search unit configured to search for a motion vector for each prediction block by using a matching process. and a sub-block level search unit configured to search for a motion vector of each of sub-blocks in the prediction block, wherein a precision of a local search by the PU level search unit is lower than a precision of a local search by the sub-block level search unit.

Motion vector generation device, a video decoding device and a video coding 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.

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Sakai, Japan

Tomohiro Ikai