Nippon Hoso' Kyokai

Shimpei Nemoto

Atsuro Ichigaya

Shunsuke Iwamura

Kazuhisa Iguchi

Yuichi Kondo

A method includes: decoding a bitstream and thereby outputting a transform coefficients for each color component of the block, a first flag indicating for each color component whether the block includes a non-zero transform coefficient, and a second flag indicating whether the block has been encoded using a color space transform that transforming a color space of a prediction residual from a color space of the original image to another color space; performing a color space inverse transform for the prediction residual restored from the transform coefficients, when the second flag indicates that the block has been encoded using the color space transform; and determining whether to perform chroma residual scaling for the prediction residual of the chrominance component, based on the first flag of a chrominance component and the second flag, the chroma residual scaling that performs scaling based on a luminance component corresponding to the chrominance component.

Decoding device, program, and decoding method using chroma residual scaling

An image encoding devicethat encodes an encoding target block obtained by dividing an image, the image encoding device including: an intra predictorconfigured to predict the encoding target block through intra prediction to generate a prediction block; and a transformerconfigured to perform orthogonal transform processing on a prediction residual representing an error of the prediction block with respect to the encoding target block. The intra predictor includes: a weighted controllerconfigured to control the weighted combining processing dependent on positions of prediction pixels within the prediction block based on a type of transform to be applied in the orthogonal transform processing in the transformer; and a correctorconfigured to correct the prediction pixels by performing the weighted combining processing on reference pixels adjacent to the encoding target block and the prediction pixels.

Image encoding device, image decoding device and program

An image encoding device () includes a motion compensation predictor () configured to generate a prediction image corresponding to a target image by performing motion compensation prediction using a plurality of reference images, and an evaluator () configured to evaluate prediction accuracy of the prediction image for each image portion including one or more pixels by calculating a degree of similarity between the plurality of reference images for each image portion.

A deblocking filter device according to a first feature includes: a deblocking filter configured to perform a filter process on a boundary between a first reconstructed block and a second reconstructed block adjacent to the first reconstructed block; and a filter controller configured to control boundary filtering strength of the deblocking filter based on whether or not at least one of the first reconstructed block and the second reconstructed block is encoded using JCCR (Joint coding of chroma residual) in which one joint prediction residual is generated from prediction residuals of a Cb chrominance component and a Cr chrominance component.

Deblocking filter device, decoding device and program

An encoding device that performs encoding on each of blocks obtained by dividing an image includes: a weighted bi-predictorconfigured to generate a prediction block of an encoding-target block by weighted-averaging a plurality of reference images using weighted coefficients selected from a weighted coefficient set including a plurality of weighted coefficients; and a filter controllerconfigured to control deblocking filter based on the weighted coefficients applied by the weighted bi-predictorto each of the two blocks adjacent blocks.

Encoding device, decoding device and program

An encoding device includes: a quantizer configured to perform a quantization process; a loop filter configured to perform an adaptive loop filter process; and an entropy encoder configured to output a bit stream including an adaptive parameter set. The adaptive parameter set includes encoding tool type information indicating which parameter of parameter candidates including one of a scaling list parameter including a parameter of a scaling list that controls the quantization process and an adaptive loop filter parameter including a parameter of a filter coefficient used in the adaptive loop filter process is included in the adaptive parameter set, and a chrominance parameter present flag indicating whether or not a parameter for a chrominance signal is present in the adaptive parameter set, and the chrominance parameter present flag is applied in common to the scaling list parameter and the adaptive loop filter parameter.

The encoding device includes: a predictor configured to generate, for each component, a prediction block corresponding to an encoding-target block; a residual generator configured to generate, for each component, a prediction residual representing a difference between the encoding-target block and the prediction block; a mode selector configured to select one mode either an individual encoding mode performing a transform process and a quantization process on a prediction residual of the first component and a prediction residual of the second component for each single component, or a joint encoding mode performing a transform process and a quantization process on a joint prediction residual generated from the prediction residual of the first component and the prediction residual of the second component; a quantization controller configured to determine a quantization matrix to be applied in the quantization process based on the mode selected by the mode selector.

A prediction image correcting device comprises a predictor () configured to predict a target image block obtained by dividing a present image frame by using a plurality of reference images to generate a prediction image corresponding to the target image block a prediction accuracy evaluator () configured to evaluate prediction accuracy of the prediction image based on a degree of similarity between the plurality of reference images used for generating the prediction image and a corrector () configured to perform correction processing on the prediction image by using a decoded neighboring block adjacent to the target image block, wherein the corrector is configured to control the correction processing based at least on an evaluation result of the prediction accuracy evaluator.

Prediction image correcting device, image encoding device, image decoding device, and program

An encoding device comprises: a transformer/quantizer configured to perform a transform process and a quantization process on a residual signal that represents a difference between an encoding-target block and a prediction block obtained by predicting the encoding-target block; an inverse quantizer/inverse transformer configured to restore the residual signal by performing an inverse quantization process and an inverse transform process on transform coefficients obtained by the transformer/quantizer; a combiner configured to reconstruct the encoding-target block by combining the restored residual signal and the prediction block; a deblocking filter configured to perform a filter process on a boundary between two blocks including the reconstructed block and a block adjacent to the reconstructed block; and a filter controller configured to control the deblocking filter, based on a type of the transform process applied with respect to the two blocks.

An encoding deviceincludes: a transformerconfigured to calculate an orthogonal transform coefficient by performing an orthogonal transformation process on a residual image indicating a difference between the input image and a predicted image of the input image; a quantizerconfigured to generate quantization coefficient by quantizing the orthogonal transform coefficient based on a quantization parameter; an entropy encoderconfigured to generate encoded data by encoding the quantization coefficient; an image decoderconfigured to restore an orthogonal transform coefficient from the quantization coefficient based on the quantization parameter and generate a pre-filtering image by adding the predicted image to a residual image restored by performing inverse orthogonal transformation on the orthogonal transform coefficient; and a deblocking filterconfigured to perform a filtering process on the pre-filtering image and control a filtering strength depending on a result of comparison between a luminance signal level of the pre-filtering image and a luminance threshold value.

Encoding device, decoding device, and program

An encoding device encodes each encoding-target block. The encoding device includes: a predictor configured to generate, for each of the components, a prediction block corresponding to the encoding-target block; a residual generator configured to generate, for each of the components, a prediction residual that represents a difference between the encoding-target block and the prediction block; a color space transformer configured to perform a color space transform process on the prediction residual of each of the components; a transformer configured to generate transform coefficients by performing a transform process on the prediction residual; a quantization controller configured to determine a scaling list to be used in a quantization process on the transform coefficients; and a quantizer configured to perform the quantization process on the transform coefficients by using the determined scaling list, wherein the quantization controller is configured to determine the scaling list, based on the color space transform process.

Encoding device and decoding device that determine a scaling list

An intra prediction device predicts, by intra prediction, a luminance block and a chrominance block obtained by dividing an image. The intra prediction device includes a cross-component linear model predictor configured to predict the chrominance block from a decoded luminance block at a position corresponding to a position of the chrominance block using a linear model calculated from respective luminance and chrominance reference pixels around the chrominance block. The cross-component linear model predictor includes a reference pixel position selector configured to select linear model calculation pixel positions that are positions of the reference pixels to be used to calculate the linear model based on a luminance intra prediction mode that is an intra prediction mode applied to the intra prediction of the decoded luminance block.

Intra prediction device, image encoding device, image decoding device and program

An encoding device performing an encoding process in units of blocks into which images constituted by luminance signals and chrominance signals are divided includes: a predictor configured to predict a target chrominance block which is an encoding target block of the chrominance signals and generate a prediction chrominance block; a residual generator configured to generate a chrominance prediction residual indicating a difference between the target chrominance block and the prediction chrominance block; and a transformer configured to apply a transform process to the chrominance prediction residual and generate transform coefficients, wherein the transformer is configured to control, according to a signal format of the images, a transform type to be applied to the transform process.

An image encoding device encodes a block-based target image. The image encoding device comprises, in a transform skip mode in which orthogonal transform processing of the target image is skipped, a motion compensation predictor configured to generate a prediction image corresponding to the target image by performing motion compensation prediction using a plurality of reference images, an evaluator configured to evaluate a degree of similarity between the plurality of reference images on a pixel-by-pixel basis, a subtractor configured to calculate prediction residuals each indicating a difference between the target image and the prediction image on a pixel-by-pixel basis, a rearranger configured to rearrange the prediction residuals based on a result of evaluation by the evaluator and an encoder configured to encode the prediction residuals rearranged by the rearranger.

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Tokyo, Japan

Shimpei Nemoto