Triangle Merge Mode Candidate List Derivation Simplification

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Solution Overview

Problem

The candidate list derivation for the triangle Merge mode in video coding is complex and involves heavy data dependency, making it difficult to speed up the process effectively.

Innovation Solution

A method is proposed to generate a first candidate list and then a second candidate list for the triangle Merge mode, reusing the normal Merge candidate list and modifying bi-prediction candidates to uni-prediction candidates, with specific pruning processes to reduce redundancy and simplify the derivation process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the normal Merge candidate list derivation process is used for triangle Merge mode, then the coding accuracy is maintained, but the computational complexity and data dependency increase significantly

Engineering Contradiction:
Improvecoding accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The candidate list for triangle Merge mode is segmented into two separate lists: a first candidate list containing spatial candidates and a second candidate list containing temporal candidates. This segmentation allows each list to be derived independently with reduced data dependency, while together they provide comprehensive motion prediction candidates maintaining coding accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single unified candidate list to a two-dimensional candidate list structure (spatial and temporal dimensions). The first candidate list derives spatial motion candidates from neighboring blocks, while the second candidate list derives temporal motion candidates from co-located blocks in reference pictures, adding a temporal dimension to the candidate selection process.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If the complex pruning processes are applied to remove redundancy in triangle Merge mode, then the candidate quality is improved, but the processing time and computational load increase

Engineering Contradiction:
Improvecandidate qualityVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The invention performs preliminary organization of motion candidates by dividing them into spatial and temporal categories before final selection. The first candidate list is prepared with spatial candidates and the second with temporal candidates, allowing the decoder to efficiently process and select from pre-organized lists without requiring complex post-processing pruning operations.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If bi-prediction candidates are used in triangle Merge mode, then the prediction accuracy is improved, but the data dependency and processing complexity increase

Engineering Contradiction:
Improveprediction accuracyVSAvoiddata dependency
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The bi-prediction capability is segmented into separate spatial and temporal components. The first candidate list handles spatial bi-prediction candidates from neighboring blocks, while the second candidate list handles temporal bi-prediction candidates from reference pictures. This segmentation reduces data dependency by allowing independent derivation of each list.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11856194B2Method and apparatus of simplified triangle merge mode candidate list derivation
Publication Date: 2023.12.26 HFI INNOVATION INC
  • US11856194B2 patent drawing
  • US11856194B2 patent drawing
  • US11856194B2 patent drawing

AI summary

A method and apparatus of Inter prediction for video coding using a target Merge mode comprising a triangle Merge mode are disclosed. According to this method, a current block is partitioned into a first region and a second region using the target partition. A candidate list is determined. Two candidates are determined for the two regions by deriving two target candidates from the candidate list. When a selected target candidate is a uni-prediction candidate, the selected target candidate is used as one candidate; and when the selected target candidate is a bi-prediction candidate, motion information associated of the selected target candidate with List 0 or List 1 is used as one candidate. The current block or current motion information associated with the current block is encoded or decoded according to the candidate list. The candidate list is used to derive the first candidate and the second candidate.