Picture decoding device, picture decoding method, and picture decoding program with history-based candidate selection

Patent metadata

Field	Value
Publication number	US-12425635-B2
Application number	US-202418643099-A
Country	US
Kind code	B2
Filing date	Apr 23, 2024
Priority date	Dec 28, 2018
Publication date	Sep 23, 2025
Grant date	Sep 23, 2025

Abstract

A picture decoding device includes a spatial candidate derivation unit configured to derive a spatial candidate from inter prediction information of a block neighboring a decoding target block and register the derived spatial candidate as a candidate to a first candidate list, a history-based candidate derivation unit configured to generate a second candidate list by adding a history-based candidate included in a history-based candidate list as a candidate to the first candidate list, a candidate selection unit configured to select a selection candidate from candidates included in the second candidate list, and an inter prediction unit configured to perform inter prediction using the selection candidate.

First claim

What is claimed is:

1. A picture coding device for coding a moving picture using inter prediction in units of blocks and forming a bitstream, the picture coding device comprising:
a spatial motion vector predictor candidate derivation unit configured to derive a spatial candidate from inter prediction information of a block neighboring a coding target block and register the derived spatial candidate to a first motion vector predictor candidate list;
a history-based motion vector predictor candidate derivation unit configured to generate a second motion vector predictor candidate list by adding a history-based candidate to the first motion vector predictor candidate list regardless of whether or not a motion vector of the history-based candidate included in a history-based candidate list overlaps motion vectors of candidates included in the first motion vector candidate list;
a motion vector predictor candidate selection unit configured to select a first selection candidate from candidates included in the second motion vector predictor candidate list;
a spatial merge candidate derivation unit configured to derive a spatial candidate from inter prediction information of a block neighboring a coding target block and register the derived spatial candidate to a first merge candidate list;
a history-based merge candidate derivation unit configured to generate a second merge candidate list by adding a history-based candidate to the first merge candidate list when the history-based candidate included in the history-based candidates list does not overlap candidates included in the first merge candidate list; and
a merge candidate selection unit configured to select a second selection candidate from candidates included in the second merge candidate list;
a coding unit configured to code a merge flag being 1 in a merge mode and being 0 in a motion vector predictor mode, and code a merge index for selecting the second selection candidates when the merge flag is 1 and code a motion vector predictor index for selecting the first selection candidate when the merge flag is 0; and
an inter prediction unit configured to perform inter prediction using the first selection candidate or the second selection candidate.

2. A picture coding method for coding a moving picture using inter prediction in units of blocks and forming a bitstream, the picture coding method comprising:
deriving a spatial candidate from inter prediction information of a block neighboring a coding target block and register the derived spatial candidate to a first motion vector predictor candidate list;
generating a second motion vector predictor candidate list by adding a history-based candidate to the first motion vector predictor candidate list regardless of whether or not a motion vector of the history-based candidate included in a history-based candidate list overlaps motion vectors of candidates included in the first motion vector candidate list;
selecting a first selection candidate from candidates included in the second motion vector predictor candidate list;
deriving a spatial candidate from inter prediction information of a block neighboring a coding target block and register the derived spatial candidate to a first merge candidate list;
generating a second merge candidate list by adding a history-based candidate to the first merge candidate list when the history-based candidate included in the history-based candidates list does not overlap candidates included in the first merge candidate list; and
selecting a second selection candidate from candidates included in the second merge candidate list;
coding a merge flag being 1 in a merge mode and being 0 in a motion vector predictor mode, and coding a merge index for selecting the second selection candidates when the merge flag is 1 and coding a motion vector predictor index for selecting the first selection candidate when the merge flag is 0; and
performing inter prediction using the first selection candidate or the second selection candidate.

3. A picture decoding device comprising:
a spatial motion vector predictor candidate derivation unit configured to derive a spatial candidate from inter prediction information of a block neighboring a decoding target block and register the derived spatial candidate to a first motion vector predictor candidate list;
a history-based motion vector predictor candidate derivation unit configured to generate a second motion vector predictor candidate list by adding a history-based candidate to the first motion vector predictor candidate list regardless of whether or not a motion vector of the history-based candidate included in a history-based candidate list overlaps motion vectors of candidates included in the first motion vector candidate list;
a motion vector predictor candidate selection unit configured to select a first selection candidate from candidates included in the second motion vector predictor candidate list;
a spatial merge candidate derivation unit configured to derive a spatial candidate from inter prediction information of a block neighboring a decoding target block and register the derived spatial candidate to a first merge candidate list;
a history-based merge candidate derivation unit configured to generate a second merge candidate list by adding a history-based candidate to the first merge candidate list when the history-based candidate included in the history-based candidates list does not overlap candidates included in the first merge candidate list; and
a merge candidate selection unit configured to select a second selection candidate from candidates included in the second merge candidate list;
a decoding unit configured to decode a merge flag being 1 in a merge mode and being 0 in a motion vector predictor mode, and decode a merge index for selecting the second selection candidates when the merge flag is 1 and decode a motion vector predictor index for selecting the first selection candidate when the merge flag is 0; and
an inter prediction unit configured to perform inter prediction using the first selection candidate or the second selection candidate.

4. A picture decoding method comprising:
deriving a spatial candidate from inter prediction information of a block neighboring a decoding target block and registering the derived spatial candidate to a first motion vector predictor candidate list;
generating a second motion vector predictor candidate list by adding a history-based candidate to the first motion vector predictor candidate list regardless of whether or not a motion vector of the history-based candidate included in a history-based candidate list overlaps motion vectors of candidates included in the first motion vector candidate list;
selecting a first selection candidate from candidates included in the second motion vector predictor candidate list;
deriving a spatial candidate from inter prediction information of a block neighboring a decoding target block and registering the derived spatial candidate to a first merge candidate list;
generating a second merge candidate list by adding a history-based candidate to the first merge candidate list when the history-based candidate included in the history-based candidates list does not overlap candidates included in the first merge candidate list; and
selecting a second selection candidate from candidates included in the second merge candidate list;
decoding a merge flag being 1 in a merge mode and being 0 in a motion vector predictor mode, and decoding a merge index for selecting the second selection candidates when the merge flag is 1 and decoding a motion vector predictor index for selecting the first selection candidate when the merge flag is 0; and
performing inter prediction using the first selection candidate or the second selection candidate.

5. A storing method

Assignees

• Godo Kaisha Ip Bridge 1

Inventors

• Takehara Hideki
• Nakamura Hiroya
• Sakazume Satoru
• Fukushima Shigeru
• Kumakura Toru
• Kurashige Hiroyuki

Classifications

• G06T9/004

  Predictors, e.g. intraframe, interframe coding · CPC title

• G06T9/40

  Tree coding, e.g. quadtree, octree · CPC title

• H04N19/176

  the region being a block, e.g. a macroblock · CPC title

• H04N19/159

  Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction · CPC title

• H04N19/105 Primary

  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 · CPC title