# US 2018/0295366 A1 · Image coding method, image coding apparatus, image decoding method, image decoding apparatus, and image coding and decoding apparatus

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- Number: US 2018/0295366 A1
- Document ID: US20180295366A1
- Status: Published application
- Kind: A1
- Application number: 16/008,533
- Filed: 2018-06-14
- Published: 2018-10-11
- Earliest claimed: 2011-05-27
- Assignees: Sun Patent Trust
- Applicants: Sun Patent Trust
- Inventors: Toshiyasu SUGIO; Takahiro NISHI; Youji SHIBAHARA; Kyoko TANIKAWA; Hisao SASAI; Toru MATSUNOBU
- Web page: https://patentgrep.com/patent/US20180295366A1

## CPC

- H04N 19/139: Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
- H04N 19/102: characterised by the element, parameter or selection affected or controlled by the adaptive coding
- 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 19/13: Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
- H04N 19/134: characterised by the element, parameter or criterion affecting or controlling the adaptive coding
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/51: Motion estimation or motion compensation
- H04N 19/52: by predictive encoding
- H04N 19/577: Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- H04N 19/184: the unit being bits, e.g. of the compressed video stream
- H04N 19/197: {including determination of the initial value of an encoding parameter (H04N19/56 takes precedence)}
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An image decoding method and apparatus derive: a first candidate having a first motion vector; a second candidate having a second motion vector and a first reference picture index value that identifies a first reference picture corresponding to the second motion vector; and a third candidate having a third motion vector and a second reference picture index value that identifies a second reference picture corresponding to the third motion vector. The second and third motion vectors are first and second zero vectors. The first and second reference picture index values are different. A coded index attached to the bitstream is decoded using a maximum number of candidates including the first, second, and third candidates. The coded index indicates one candidate of the candidates. The candidate is selected based on the coded index and is used for decoding a current block.

## Claims

### Claim 1

An image decoding method for decoding a current block included in a bitstream, the image decoding method comprising:
deriving a first candidate having a first motion vector that has been used to decode a first block;
deriving a second candidate having a second motion vector and a first reference picture index value that identifies a first reference picture corresponding to the second motion vector, the second motion vector being a first zero vector;
deriving a third candidate having a third motion vector and a second reference picture index value that identifies a second reference picture corresponding to the third motion vector, the third motion vector being a second zero vector, the first reference picture index value being different from the second reference picture index value;
decoding a coded index attached to the bitstream using a maximum number of a plurality of candidates including the first candidate, the second candidate, and the third candidate, the coded index indicating one candidate of the plurality of candidates; and
selecting the candidate, based on the coded index, the candidate being used for decoding the current block, the selected candidate including a motion vector and a reference picture index value.

### Claim 2

An image decoding apparatus that decodes a current block included in a bitstream, the image decoding apparatus comprising:
a processor; and
a non-transitory memory,
wherein the processor performs, using the non-transitory memory, processes including:
deriving a first candidate having a first motion vector that has been used to decode a first block;
deriving a second candidate having a second motion vector and a first reference picture index value that identifies a first reference picture corresponding to the second motion vector, the second motion vector being a first zero vector;
deriving a third candidate having a third motion vector and a second reference picture index value that identifies a second reference picture corresponding to the third motion vector, the third motion vector being a second zero vector, the first reference picture index value being different from the second reference picture index value;
decoding a coded index attached to the bitstream using a maximum number of a plurality of candidates including the first candidate, the second candidate, and the third candidate, the coded index indicating one candidate of the plurality of candidates; and
selecting the candidate, based on the coded index, the candidate being used for decoding the current block, the selected candidate including a motion vector and a reference picture index value.