Sub-Block Intra Block Copy for Complex Video Block Coding

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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 reference sample usage and motion vector derivation, allowing for more precise and efficient coding techniques such as intra, inter, and palette modes, along with motion candidate list construction and table updates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the current block is coded using traditional IBC technique, then the coding simplicity is maintained, but the compression efficiency and quality of decompressed video are insufficient for complex motion patterns

Engineering Contradiction:

Improvecompression efficiencyVSAvoidcoding complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The current block is divided into multiple sub-blocks, and each sub-block is independently coded using IBC technique. This segmentation allows for more precise motion representation and improved compression efficiency while maintaining manageable coding complexity through localized processing

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sub-blocks can use different reference blocks and motion vectors tailored to their local characteristics. This local optimization enables better adaptation to complex motion patterns within different regions of the current block, improving overall compression efficiency

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If the current block is split into multiple sub-blocks with different coding techniques, then the adaptability to diverse block structures is improved, but the device complexity increases

Engineering Contradiction:

Improveadaptability to block structuresVSAvoidcoding complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The coding approach dynamically adapts to the characteristics of each sub-block by selecting appropriate coding techniques (intra, inter, or palette modes) based on local content analysis. This dynamic adaptation improves versatility while managing complexity through context-dependent decision making

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Different parameters such as reference block positions, motion vectors, and coding modes are changed and optimized for each sub-block based on its specific characteristics. This parameter optimization enables better adaptation to diverse block structures while maintaining systematic processing

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If sub-block intra block copy mode is used with multiple reference samples, then the measurement precision of motion representation is improved, but the loss of information in bitstream increases

Engineering Contradiction:

Improvemotion vector precisionVSAvoidbitstream information

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

Reference samples are copied from previously decoded regions within the same picture to predict current sub-block content. This copying mechanism enables precise motion representation by reusing existing data, reducing the need to transmit additional information and thereby minimizing bitstream loss

Inventive Principle:

Principle #26Copying

Data Source

PatentUS20260032241A1Sub-block based intra block copy

Publication Date: 2026.01.29 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. 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. The method also includes performing the conversion based on the determining.