Geometric partition mode with explicit motion signaling

Patent metadata

Field	Value
Publication number	US-12457335-B2
Application number	US-202318378120-A
Country	US
Kind code	B2
Filing date	Oct 9, 2023
Priority date	Apr 9, 2021
Publication date	Oct 28, 2025
Grant date	Oct 28, 2025

Abstract

Methods, apparatuses, and non-transitory computer-readable storage mediums are provided for decoding a video block in geometry partition mode (GPM). The method includes: partitioning the video block into first and second geometric partitions; obtaining a first prediction list for the first geometric partition and obtaining a second prediction list for the second geometric partition; obtaining motion vectors (MVs) for the first and second geometric partitions by applying a GPM with explicit motion signaling (EMS) to the first and second geometric partitions based on the first and second prediction lists; and obtaining prediction samples of the first and second geometric partitions based on the MVs.

First claim

What is claimed is:

1. A method for decoding a video block in geometry partition mode (GPM), comprising:
partitioning the video block into first and second geometric partitions;
obtaining a first prediction list for the first geometric partition and obtaining a second prediction list for the second geometric partition;
obtaining motion vectors (MVs) for the first and second geometric partitions by applying a GPM with explicit motion signaling (EMS) to the first and second geometric partitions based on the first and second prediction lists; and
obtaining prediction samples of the first and second geometric partitions based on the MVs,
the method further comprising:
in response to determining that a symmetric motion vector difference (SMVD) syntax element sym_mvd_flag indicating whether the video block is coded by a SMVD mode indicates that the video block is not coded by the SMVD mode, receiving a GPM flag gpm_flag, wherein the GPM flag gpm_flag indicates whether a GPM mode is enabled for the first or second geometric partition; and
in response to determining that the GPM flag gpm_flag is equal to 1, inferring the SMVD syntax element sym_mvd_flag as 0 indicating that the video block is not coded by the SMVD mode.

2. The method of claim 1 , wherein applying the GPM with EMS further comprising:
receiving one or more first syntax elements for the first geometric partition, comprising a reference picture index syntax element ref_idx_l0, a motion vector prediction (MVP) index flag mvp_l0_flag and a first motion vector difference (MVD) coding syntax element mvd_coding, wherein the reference picture index ref_idx_l0 indicates a reference picture index of the first geometric partition, the MVP index flag mvp_l0_flag indicates an MVP index of the first geometric partition, and the first MVD coding syntax element mvd_coding indicates an MVD of the first geometric partition; and
receiving one or more second syntax elements for the second geometric partition, comprising a reference picture index syntax element ref_idx_l1, a motion vector prediction (MVP) index flag mvp_l1_flag and a second MVD coding syntax element mvd_coding, wherein the reference picture index ref_idx_l1 indicates a reference picture index of the second geometric partition, the MVP index flag mvp_l1_flag indicates an MVP index of the second geometric partition, and the second MVD coding syntax element mvd_coding indicates an MVD of the second geometric partition.

3. The method of claim 1 , wherein the first prediction list is list L0 and the second prediction list is list L1.

4. The method of claim 3 , wherein obtaining the first prediction list for the first geometric partition and obtaining the second prediction list for the second geometric partition further comprises:
receiving a first GPM prediction direction flag gpm_pred_dir_flag0 indicating a corresponding prediction list that an MV of the first geometric partition is from; and
receiving a second GPM prediction direction flag gpm_pred_dir_flag1 indicating a corresponding prediction list that an MV of the second geometric partition is from.

5. The method of claim 4 , further comprising:
in response to determining that the first GPM prediction direction flag gpm_pred_dir_flag0 is equal to 1, determining that the MV of the first geometric partition is from list L1; and
in response to determining that the first GPM prediction direction flag gpm_pred_dir_flag0 is equal to 0, determining that the MV of the first geometric partition is from list L0.

6. The method of claim 4 , further comprising:
in response to determining that the second GPM prediction direction flag gpm_pred_dir_flag1 is equal to 1, determining that the MV of the second geometric partition is from list L0; and
in response to determining that the second GPM prediction direction flag gpm_pred_dir_flag1 is equal to 0, determining that the MV of the second geometric partition is from list L1.

7. The method of claim 1 , further comprising:
receiving one or more syntax elements that conditions the GPM flag gpm_flag.

8. The method of claim 7 , wherein the one or more syntax elements comprise an inter prediction syntax element inter_pred_idc indicating whether a bi-prediction is applied and an affine mode syntax element inter_affine_flag indicating whether the video block is coded by an affine mode,
wherein the method further comprises:
in response to determining that the inter prediction syntax element inter_pred_idc indicates that the bi-prediction is applied and the affine mode syntax element inter_affine_flag indicates that the video block is not coded by the affine mode, receiving the GPM flag gpm_flag.

9. The method of claim 8 ,
wherein the method further comprises:
in response to determining that the inter prediction syntax element inter_pred_idc indicates that the bi-prediction is applied, the affine mode syntax element inter_affine_flag indicates that the video block is not coded by the affine mode, and the SMVD syntax element sym_mvd_flag indicates that the video block is not coded by the SMVD mode, receiving the GPM flag gpm_flag.

10. The method of claim 9 , further comprising:
in response to determining that the GPM flag gpm_flag is equal to 1, receiving a GPM partition syntax element gpm_partition_idx indicating a selected GPM mode for the video block.

11. The method of claim 9 , further comprising:
in response to determining that the GMP flag gpm_flag is not signaled, inferring a value of the GMP flag gpm_flag is equal to 0.

12. The method of claim 1 , further comprising:
receiving the GPM flag gpm_flag that conditions one or more syntax elements.

13. The method of claim 12 , wherein the one or more syntax elements comprise an inter prediction syntax element inter_pred_idc indicating whether a bi-prediction is applied and an affine mode syntax element inter_affine_flag indicating whether the video block is coded by an affine mode, and
wherein the method further comprises:
in response to determining that the GPM flag gpm_flag is equal to 1, bypassing the inter prediction syntax element inter_pred_idc and the affine mode syntax element inter_affine_flag.

14. The method of claim 13 ,
wherein the method further comprises:
in response to determining that the GPM flag gpm_flag is equal to 1, bypassing the inter prediction syntax element inter_pred_idc, the affine mode syntax element inter_affine_flag, and the SMVD syntax element sym_mvd_flag.

15. The method of claim 14 , further comprising:
in response to determining that the GPM flag gpm_flag is equal to 1, inferring the inter prediction syntax element inter_pred_idc as PRED_BI indicating that a bi-prediction is applied, and inferring the affine mode syntax element inter_affine_flag as 0 indicating that the video block is not coded by an affine mode.

16. An apparatus for video decoding, comprising:
one or more processors; and
a non-transitory computer-readable storage medium configured to store instructions executable by the one or more processors; wherein the one or more processors, upon execution of the instructions, are configured to perform acts comprising:
partitioning a video block into first and second geometric partitions;
obtaining a first prediction list for the first geometric partition and obtaining a second prediction list for the second geometric partition;
obtaining motion vectors (MVs) for the first and second geometric partitions by applying a geometry partition mode (GPM) with explicit motion signaling (EMS) to the first and second geometric partitions based on first and second prediction lists; and
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Assignees

• Beijing Dajia Internet Information Tech Co Ltd

Inventors

• Xiu Xiaoyu
• Chen Wei
• Kuo Che-Wei
• Chen Yi-Wen
• Jhu Hong-Jheng
• Wang Xianglin
• Yu Bing

Classifications

• H04N19/70

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

• H04N19/513

  Processing of motion vectors · CPC title

• H04N19/176

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

• H04N19/139

  Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability · CPC title

• H04N19/132

  Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking · CPC title