Nippon Telegraph and Telephone Corporation

Shohei Matsuo

Seishi Takamura

Hirohisa Jozawa

Yukihiro Bandoh

Kazuto Kamikura

Yoshiyuki Yashima

Atsushi Shimizu

Hiroshi Fujii

Masaaki Matsumura

Regions based on which an interpolation method of a fractional-accuracy pixel is switched are optimized, and the interpolation method is switched for each of the divided regions, thereby reducing residual energy of inter-frame prediction with motion compensation. A video encoding apparatus is provided with: an encoding information acquiring unit which acquires encoding information for each block; a region classification unit which performs a region classification on a block-by-block basis in accordance with the encoding information; a divided region redefinition processing unit which shifts a region dividing line in a horizontal direction, a region dividing line in a vertical direction, or both the region dividing line in the horizontal direction and the region dividing line in the vertical direction based on a result of the region classification, and determines a region dividing line with which density of blocks belonging to a particular region classification is greater than or equal to a predetermined threshold value; an interpolation method switching unit which switches an interpolation method of a fractional-accuracy pixel for each of divided regions divided by the region dividing line; an interpolation performing unit which performs interpolation of the fractional-accuracy pixel for each of the divided regions; a picture encoding unit which encodes a picture using inter-frame prediction with motion compensation of fractional-accuracy for an interpolated picture; and a region classification information encoding unit which encodes information on the region classification.

Video encoding method, video decoding method, video encoding apparatus, video decoding apparatus, and programs thereof

Setting a reference pixel signal from a decoded pixel signal in intra-prediction in which a prediction signal is generated in the same frame, acquiring prediction mode identification information that identifies an intra-prediction mode, generating a prediction signal based on the reference pixel signal and the prediction mode identification information, making a determination regarding correction of the prediction signal using a reference pixel having a shorter distance from a pixel that is a prediction target in the intra-prediction mode identified by the prediction mode identification information, and correcting the generated prediction signal according to a result of the determination are included in order to provide an image encoding method and an image decoding method capable of improving subjective image quality and coding efficiency using a closer decoded pixel in an intra-prediction process.

Intra-prediction encoding method, intra-prediction decoding method, intra-prediction encoding apparatus, intra-prediction decoding apparatus, program therefor and recording medium having program recorded thereon

A video encoding device uses motion-compensated inter-frame prediction by dividing an image into blocks, each block a predetermined size, designating a first component value of a plurality of component values of a motion vector (MV) between an encoding target block and a neighboring block, designating a second component value, and encoding each first and second component values; a first component encoding means encodes a difference value of a first component and a second component encoding means, which obtains a probability of occurrence of a candidate value for the second component value of the MV of the encoding target block, based on a difference value between the first component value of the neighboring block MV and the first component value of the encoding target block MV and the second component value of the neighboring block MV, specifies a codeword of the second component value, encoding it based on the occurrence probability.

Video encoding device, video decoding device, video encoding method, video decoding method, and non-transitory computer-readable recording media that use similarity between components of motion vector

The prediction error energy in inter-frame prediction with motion compensation is reduced and the coding efficiency is improved. A video encoding method using fractional-accuracy motion compensation includes: a step of generating multiple weighted filter coefficients from multiple interpolation filter sets using weight parameters which designate weight values of interpolation filter coefficients; a step of selecting weighted filter coefficients which minimize prediction error energy in the fractional-accuracy motion compensation from among the weighted filter coefficients; a step of interpolating fractional-accuracy pixels for a reference picture by application of an interpolation filter with the selected weighted filter coefficients and encoding an input picture with the fractional-accuracy motion compensation; and a step of encoding the weight parameters used for generating the selected weighted filter coefficients and the interpolation filter coefficients and adding encoded weight parameters and encoded interpolation filter coefficients to an encoded bitstream.

Method and apparatus for encoding video, method and apparatus for decoding video, and programs therefor

A reduction in residual energy of inter-frame prediction with motion compensation and improvement in encoding efficiency are achieved by using a region-dividing type adaptive interpolation filter that takes an edge property of a picture into consideration. An edge calculation unit calculates edge information from reference picture data designated by a motion vector. A region dividing unit divides an encoding target frame into a plurality of regions that are units to which interpolation filters are adaptively applied based on the edge information. A filter coefficient optimizing unit optimizes an interpolation filter for a fractional-accuracy pixel for each of the regions. A reference picture interpolating unit interpolates the fractional-accuracy pixel of a reference picture using the optimized interpolation filter, and a predictive encoding unit performs predictive encoding using motion compensation of fractional-accuracy.

A method for encoding an image using an intraframe prediction is provided which includes selecting a gradient of a pixel value that is indicated by an image signal to be predicted among a plurality of gradient candidates, generating a predicted signal by applying a gradient in accordance with the distance from a prediction reference pixel based on the gradient, intraframe-encoding the image signal to be predicted based on the predicted signal, and encoding information indicating the size of the selected gradient. Alternatively, the method includes estimating the gradient of a pixel value that is indicated by an image signal to be predicted based on an image signal which has already been encoded, generating a predicted signal by applying a gradient in accordance with the distance from a prediction reference pixel based on the gradient, and intraframe-encoding the image signal to be predicted based on the predicted signal.

Image encoding and decoding apparatuses, image encoding and decoding methods, programs thereof, and recording media recorded with the programs

A video encoding method includes setting candidates for reference pixels to pixels within a predetermined distance range measured from an encoding target block; generating a predicted signal by sequentially selecting reference pixels used for the intra prediction of the encoding target block from among the reference pixel candidates while changing a distance condition from the encoding target block, and by generating the predicted signal based on the reference pixels for each distance condition; computing an encoding cost required for subjecting the encoding target block to intra prediction encoding using each generated predicted signal; finally determining reference pixels used for the intra prediction of the encoding target block based on each computed encoding cost; and encoding information which indicates the position of the determined reference pixels.

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Yokosuka, Japan

Shohei Matsuo