Sharp Kabushiki Kaisha Corporation

Sharp Corporation

Tianyang Zhou

Tomohiro Ikai

Eiichi Sasaki

Tomoko Aono

Yukinobu Yasugi

Tomonori Hashimoto

Takeshi Chujoh

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

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

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

A video decoding apparatus including a parameter decoding circuit, a prediction parameter derivation circuit, a motion compensation circuit, and a weighted prediction circuit is provided. The parameter decoding circuit is configured to decode a flag and a syntax element. The prediction parameter derivation circuit is configured to derive inter prediction parameters. The motion compensation circuit is configured to generate interpolation images based on the inter prediction parameters and reference pictures. The weighted prediction circuit is configured to derive the weight coefficients using the syntax element, and generate a prediction image using the interpolation images and the weight coefficients. When the flag indicates that the weighted prediction information is present in the slice header, the weighted prediction circuit sets a variable NumWeightL1 indicating a number of weights for a reference picture list 1 to be equal to a value of a variable NumRefIdxActive[1] derived from the slice header.

Video decoding apparatus generating a prediction image using interpolation images and weight coefficients

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.

A video decoding apparatus is a video decoding apparatus for deriving a prediction image by using a reference picture included in a reference picture list. The video decoding apparatus includes: a parameter decoder configured to decode (i) one or more reference picture list structures, and (ii) a first flag indicating whether first reference picture list information is present in a slice header whose nal_unit_type is an IDR picture, the one or more reference picture list structures and the first flag being included in a sequence parameter set, and a second flag indicating whether or not second reference picture list information is present in a picture header, the second flag being included in a picture parameter set; and a prediction parameter derivation unit configured to (i) derive the first reference picture list information by using nal_unit_type or the first flag and the second flag in the slice header, or derive the second reference picture list information by using the second flag in the picture header, and (ii) derive the reference picture list, based on the one or more reference picture list structures. In a case that the first reference picture list is not derived, the number of entries of the one or more reference picture list structures is estimated to be 0.

Video decoding apparatus, video coding apparatus, video decoding method, and video coding method

In a case that two reference picture lists are selected with one index value, the reference picture lists may not be determinable depending on the number of two reference picture list structures. Provided is a prediction unit that decodes a reference picture list structure including multiple reference picture lists and selects two reference picture lists from the reference picture list structure for each picture or for each slice. The prediction unit selects two reference picture lists with one index value depending on the number of two reference picture list structures.

Video coding apparatus and video decoding apparatus

A video decoding apparatus is provided. The video decoding apparatus includes a parameter decoding circuit, a prediction parameter derivation circuit, a motion compensation circuit, and a weighted prediction circuit to derive weight coefficients.

Video decoding apparatus using parameter decoding circuit to derive weight coefficients

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&#xd7;8 block in a luma size, 0 is derived without decoding qt_split_cu_flag, and in a case of an 8&#xd7;4/4&#xd7;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.

An apparatus includes an inter prediction unit configured to decode multiple reference picture list structures and to select one reference picture list structure from the multiple reference picture list structures on a per picture basis or on a per slice basis, wherein in the multiple reference picture list structures, the number of all reference pictures is one or more.

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Sakai, Japan

Tianyang Zhou