Sub-Block Intra-Block Copy for Complex Video Motion

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Solution Overview

Problem

Existing video coding standards face challenges in efficiently utilizing intra block copy (IBC) techniques for improved compression and quality of decompressed video, particularly in handling complex motion patterns and diverse block structures.

Innovation Solution

The implementation of sub-block intra block copy (sbIBC) coding mode, which splits current blocks into multiple sub-blocks for enhanced IBC, utilizing reference samples from video regions and applying various coding techniques like intra, inter, and palette modes, along with motion vector processing and candidate list constructions, to optimize video encoding and decoding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the current block is split into multiple sub-blocks for IBC coding, then the compression efficiency and visual fidelity are improved, but the computational complexity and processing time increase

Engineering Contradiction:

Improvecompression efficiencyVSAvoidcomputational complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The current block is divided into multiple sub-blocks (e.g., 4 sub-blocks for a 16x16 block) that can be independently coded using IBC techniques. Each sub-block has its own motion vector and reference block selection, allowing finer-grained motion compensation that improves compression efficiency while managing complexity through structured partitioning.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different coding techniques (IBC, intra, inter, palette modes) are applied to different sub-blocks based on local characteristics. The encoder selects the most appropriate mode for each sub-block, allowing high-complexity IBC coding to be applied only where it provides the greatest benefit rather than uniformly across the entire block.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If multiple coding techniques are applied to different sub-blocks, then the adaptability to diverse block structures is improved, but the decision complexity and processing overhead increase

Engineering Contradiction:

Improveadaptability to diverse block structuresVSAvoiddecision complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The coding mode is dynamically selected for each sub-block based on local content characteristics. The encoder evaluates multiple coding techniques (IBC, intra, inter, palette) and adapts the selection to match the local motion patterns and texture characteristics, providing high adaptability to diverse block structures.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Each sub-block essentially performs its own mode selection and coding based on its local characteristics. The encoder independently evaluates and applies the most suitable coding technique to each sub-block, allowing the system to self-adapt to diverse block structures without requiring complex global optimization.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12457327B2Sub-block based intra block copy

Publication Date: 2025.10.28 BYTEDANCE INC

AI summary

A method of video processing includes determining, for a conversion between a current block of a video and a bitstream of the video, that the current block is split into multiple sub-blocks, wherein at least one of the multiple blocks is coded using a modified intra-block copy (IBC) coding technique that uses reference samples from one or more video regions from a current picture of the current block; and performing the conversion based on the determining.