Motion vector prediction in video encoding and decoding

Patent metadata

Field	Value
Publication number	US-12526420-B2
Application number	US-202017620402-A
Country	US
Kind code	B2
Filing date	Jun 23, 2020
Priority date	Jun 25, 2019
Publication date	Jan 13, 2026
Grant date	Jan 13, 2026

Abstract

A video codec can involve encoding and decoding picture information and first and second flags, wherein the encoding or decoding of the picture information is based on a coding mode indicated by the first flag or the second flag, and the first flag indicates a subblock merge mode and the second flag indicates an inter affine prediction mode, and the encoding or decoding of the first flag uses Context-Based Adaptive Binary Arithmetic Coding (CABAC) based on a first probability model and encoding or decoding of the second flag uses CABAC based on a second probability model.

First claim

The invention claimed is:

1 . A method comprising:
decoding a first flag included in a bitstream, the first flag being associated with picture information, and the first flag having been encoded using a first Context-Based Arithmetic Coding (CABAC); decoding a second flag included in the bitstream, the second flag being associated with the picture information, and the second flag having been encoded using a second CABAC separate from the first CABAC; and decoding at least a portion of the picture information included in the bitstream based on a coding mode indicated by the first flag or the second flag, wherein: the first flag indicates whether or not a temporal mode is used, wherein in the temporal mode a temporal merge list is constructed that comprises only temporal motion predictor candidates; and the second flag indicates whether or not an affine prediction mode is used.

2 . The method of claim 1 , wherein:
the affine prediction mode indicates use of an affine motion compensation, and the temporal merge list comprises a subblock temporal motion vector prediction mode which derives motion information for subblocks of a block from motion information in a reference picture of a picture to which the block belongs.

3 . The method of claim 1 , wherein the temporal merge list comprises at least one of:
a subblock temporal motion vector prediction mode; a temporal motion vector prediction mode; a combined inter and intra prediction mode based on a temporal motion vector predictor; a triangle prediction mode based on a temporal motion vector predictor; or a merge motion vector difference prediction mode based on a temporal motion vector predictor.

4 . The method of claim 1 , wherein the temporal merge list is placed at one of the following positions in a block decoding process: as a first merge list, after a regular merge list, after an affine merge list, after a combined inter and intra prediction merge list, or after a triangle merge list.

5 . The method of claim 1 , wherein no temporal motion predictor candidate is included in a motion predictor candidate list other than the temporal merge list.

6 . The method of claim 1 , wherein decoding the second flag in a merge mode uses the same second CABAC as decoding the second flag in an inter mode.

7 . The method of claim 1 , wherein the first flag and the second flag are decoded at a block level of the picture information.

8 . A non-transitory computer readable medium storing executable program instructions to cause a computer executing the instructions to perform a method according to claim 1 .

9 . The non-transitory computer readable medium of claim 8 , wherein:
the affine prediction mode indicates use of an affine motion compensation, and the temporal merge list comprises a subblock temporal motion vector prediction mode which derives motion information for subblocks of a block from motion information in a reference picture of a picture to which the block belongs.

10 . A method comprising:
encoding a first flag associated with picture information, the first flag being encoded using a first Context-Based Arithmetic Coding (CABAC); encoding a second flag associated with the picture information, the second flag being encoded using a second CABAC separate from the first CABAC; and encoding at least a portion of the picture information based on a coding mode indicated by the first flag or the second flag to generate a bitstream, wherein: the first flag indicates whether or not a temporal mode is used, wherein in the temporal mode a temporal merge list is constructed that comprises only temporal motion predictor candidates; and the second flag indicates whether or not an affine prediction mode is used.

11 . The method of claim 10 , wherein:
the affine prediction mode indicates use of an affine motion compensation, and the temporal merge list comprises a subblock temporal motion vector prediction mode which derives motion information for subblocks of a block from motion information in a reference picture of a picture to which the block belongs.

12 . The method of claim 10 , wherein the first flag and the second flag are encoded at a block level of the picture information.

13 . An apparatus comprising:
one or more processors configured to:
decode a first flag included in a bitstream, the first flag being associated with picture information, and the first flag having been coded using a first Context-Based Arithmetic Coding (CABAC);
decode a second flag included in the bitstream, the second flag being associated with the picture information, and the second flag having been coded using a second CABAC separate from the first CABAC; and
decode at least a portion of the picture information included in the bitstream based on a coding mode indicated by the first flag or the second flag, wherein:
the first flag indicates whether or not a temporal mode is used, wherein in the temporal mode a temporal merge list is constructed that comprises only temporal motion predictor candidates; and
the second flag indicates whether or not an affine prediction mode is used.

14 . The apparatus of claim 13 , wherein:
the affine prediction mode indicates use of an affine motion compensation, and the temporal merge list comprises a subblock temporal motion vector prediction mode which derives motion information for subblocks of a block from motion information in a reference picture of a picture to which the block belongs.

15 . The apparatus of claim 13 , wherein decoding the second flag in a merge mode uses the same second CABAC as decoding the second flag in an inter mode.

16 . The apparatus of claim 13 , wherein the first flag and the second flag are decoded at a block level of the picture information.

17 . An apparatus comprising:
one or more processors configured to:
encode a first flag associated with picture information, the first flag being encoded using a first Context-Based Arithmetic Coding (CABAC);
encode a second flag associated with the picture information, the second flag being encoded using a second CABAC separate from the first CABAC; and
encode at least a portion of the picture information based on a coding mode indicated by the first flag or the second flag to generate a bitstream, wherein:
the first flag indicates whether or not a temporal mode is used, wherein in the temporal mode a temporal merge list is constructed that comprises only temporal motion predictor candidates; and
the second flag indicates whether or not an affine prediction mode is used.

18 . The apparatus of claim 17 , wherein:
the affine prediction mode indicates use of an affine motion compensation, and the temporal merge list comprises a subblock temporal motion vector prediction mode which derives motion information for subblocks of a block from motion information in a reference picture of a picture to which the block belongs.

19 . The apparatus of claim 17 , wherein the first flag and the second flag are encoded at a block level of the picture information.

Assignees

• Interdigital Ce Patent Holdings Sas

Inventors

• GALPIN Franck
• Leleannec Fabrice
• Robert Antoine
• Poirier Tangi

Classifications

• H04N19/70

  characterised by syntax aspects related to video coding, e.g. related to compression standards · CPC title

• H04N19/52

  by predictive encoding · CPC title

• H04N19/176

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

• H04N19/172

  the region being a picture, frame or field · CPC title

• H04N19/159

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