# US 10,321,129 B2 · Moving picture coding method and moving picture decoding method

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- Number: US 10,321,129 B2
- Document ID: US10321129B2
- Status: Granted
- Kind: B2
- Application number: 15/907,643
- Filed: 2018-02-28
- Published: 2018-07-05
- Granted: 2019-06-11
- Earliest claimed: 2002-08-08
- Assignees: Godo Kaisha IP Bridge 1
- Applicants: Godo Kaisha IP Bridge 1
- Inventors: Kiyofumi Abe; Shinya Kadono; Satoshi Kondo; Makoto Hagai
- Web page: https://patentgrep.com/patent/US10321129B2

## CPC

- H04N 19/105: Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
- H04N 19/103: Selection of coding mode or of prediction mode
- H04N 19/117: Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635)
- H04N 19/134: characterised by the element, parameter or criterion affecting or controlling the adaptive coding
- H04N 19/137: Motion inside a coding unit, e.g. average field, frame or block difference
- H04N 19/139: Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
- H04N 19/147: according to rate distortion criteria (rate-distortion as a criterion for motion estimation H04N19/567)
- H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
- H04N 19/172: the region being a picture, frame or field
- H04N 19/174: the region being a slice, e.g. a line of blocks or a group of blocks
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/177: the unit being a group of pictures [GOP]
- H04N 19/18: the unit being a set of transform coefficients
- H04N 19/182: the unit being a pixel
- H04N 19/42: characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation (H04N19/635 takes precedence)
- H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence)
- H04N 19/573: Motion compensation with multiple frame prediction using two or more reference frames in a given prediction direction
- H04N 19/577: Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
- H04N 19/58: Motion compensation with long-term prediction, i.e. the reference frame for a current frame not being the temporally closest one (H04N19/23 takes precedence)
- H04N 19/593: involving spatial prediction techniques
- H04N 19/61: in combination with predictive coding
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

According to a picture coding method, a coded picture is stored, as a reference picture, into a storage unit; commands indicating correspondence between reference pictures and reference indices for designating reference pictures and coefficients used for generation of predictive images are generated; a reference picture being used when motion compensation is performed on a current block in a current picture to be coded is designated by a reference index; a predictive image is generated by performing linear prediction on a block being obtained by motion estimation within the designated reference picture, by use of a coefficient corresponding to the reference index; a coded image signal including a coded signal obtained by coding a prediction error being a difference between the current block in the current picture to be coded and the predictive image, the commands, the reference index and the coefficient is outputted.

## Claims

### Claim 1

A image decoding method comprising:
decoding a coded image signal to obtain: first reference indices that identify first reference images for blocks to be decoded, the first reference indices and the first reference images used for a slice; second reference indices that identify second reference images, the second reference indices and the second reference images used for the slice; weighting coefficient sets used for the slice; and prediction error;
designating, based on a reference index obtained through decoding a current block, a reference image for the current block, wherein the reference index is one of the first reference indices, the reference image is one of the first reference images, and the current block is one of the blocks;
specifying, based on the reference index, a weighting coefficient set for the current block from among the weighting coefficient sets;
generating a predictive image by performing a prediction on the current block, using the specified weighting coefficient set, on pixel values of a reference block obtained from the designated reference image, the prediction comprising (i) scaling the pixel values of the reference block with a first part w1 of the specified weighting coefficient set and (ii) offsetting the scaled pixel values of the reference block by a second part c1 of the specified weighting coefficient set; and
generating a reconstructed image from the predictive image and the prediction error,
wherein at least two reference indices among the first reference indices are assigned to one reference image among the first reference images, and at least two weighting coefficient sets among the weighting coefficient sets are assigned to the one reference image, and
wherein both (i) a first index among the first reference indices and (ii) a second index among the second reference indices are used for the prediction when the current block refers to two reference blocks, and one of (i) a first index among the first reference indices and (ii) a second index among the second reference indices is used for the prediction when the current block refers to a single reference block.

### Claim 2 (depends on 1)

The image decoding method of claim 1, wherein
the coded image signal comprising encoded information of: the first reference indices; the second reference indices; the commands; the weighting coefficient sets; and the prediction error.

### Claim 3 (depends on 2)

The image decoding method of claim 2, further comprising:
decoding the coded image signal to obtain information indicating a maximum reference index value of the first reference indices, wherein the coded image signal comprising encoded information of the information indicating the maximum reference index value.

### Claim 4 (depends on 3)

The image decoding method of claim 3, further comprising:
decoding the coded image signal to obtain commands indicating an order of the first reference images for the slice, wherein the coded image signal comprising encoded information of the commands; and
specifying, based on the information indicating the maximum reference index value, an end position of the commands.

### Claim 5 (depends on 2)

The image decoding method of claim 2, wherein
at least two reference indices among the second reference indices for the slice are assigned to the one reference image among the second reference images, and at least two weighting coefficient sets for the slice among the weighting coefficient sets are assigned to the one reference image.

### Claim 6

A image decoding apparatus coupled to a memory and comprising processing circuitry, wherein the decoding apparatus, in operation:
decodes a coded image signal to obtain: first reference indices that identify first reference images for blocks to be decoded, the first reference indices and the first reference images used for a slice; second reference indices that identify second reference images, the second reference indices and the second reference images used for the slice; weighting coefficient sets used for the slice; and prediction error;
designates, based on a reference index obtained through decoding a current block, a reference image for the current block, wherein the reference index is one of the first reference indices, the reference image is one of the first reference images, and the current block is one of the blocks;
specifies, based on the reference index, a weighting coefficient set for the current block from among the weighting coefficient sets;
generates a predictive image by performing a prediction on the current block, using the specified weighting coefficient set, on pixel values of a reference block obtained from the designated reference image, the prediction comprising (i) scaling the pixel values of the reference block with a first part w1 of the specified weighting coefficient set and (ii) offsetting the scaled pixel values of the reference block by a second part c1 of the specified weighting coefficient set; and
generates a reconstructed image from the predictive image and the prediction error,
wherein at least two reference indices among the first reference indices are assigned to one reference image among the first reference images, and at least two weighting coefficient sets among the weighting coefficient sets are assigned to the one reference image, and
wherein both (i) a first index among the first reference indices and (ii) a second index among the second reference indices are used for the prediction when the current block refers to two reference blocks, and one of (i) a first index among the first reference indices and (ii) a second index among the second reference indices is used for the prediction when the current block refers to a single reference block.

### Claim 7 (depends on 6)

The image decoding method of claim 6, wherein
the coded image signal comprising encoded information of: the first reference indices; the second reference indices; the commands; the weighting coefficient sets; and the prediction error.

### Claim 8 (depends on 7)

The image decoding method of claim 7, wherein decoding apparatus, in operation:
decodes the coded image signal to obtain information indicating a maximum reference index value of the first reference indices, wherein the coded image signal comprising encoded information of the information indicating the maximum reference index value.

### Claim 9 (depends on 8)

The image decoding method of claim 8, wherein decoding apparatus, in operation:
decodes the coded image signal to obtain commands indicating an order of the first reference images for the slice, wherein the coded image signal comprising encoded information of the commands; and
specifies, based on the information indicating the maximum reference index value, an end position of the commands.

### Claim 10 (depends on 7)

The image decoding method of claim 7, wherein
at least two reference indices among the second reference indices for the slice are assigned to the one reference image among the second reference images, and at least two weighting coefficient sets for the slice among the weighting coefficient sets are assigned to the one reference image.