BV List Construction for IBC Blocks in Merge Estimation Region

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Solution Overview

Problem

Current video coding technologies face challenges in efficiently processing and compressing digital video due to increasing bandwidth demands, particularly in constructing merge candidate lists for intra block copy (IBC) blocks within a merge estimation region (MER).

Innovation Solution

The proposed solution involves constructing a list of block vector (BV) candidates for IBC blocks by excluding candidates from spatial neighbouring blocks within the MER and instead using BV candidates from outside the MER, the IBC HMVP table, or default candidates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If BV candidates from spatial neighbouring blocks within MER are used for IBC blocks, then the BV list construction follows conventional merge candidate selection, but the spatial neighbouring blocks within MER are unavailable for IBC prediction

Engineering Contradiction:

Improveavailability of BV candidatesVSAvoidBV list construction complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and excludes candidates from spatial neighbouring blocks within the MER from the BV list construction process. Instead of using these unavailable candidates, the method selectively includes BV candidates from outside the MER, IBC HMVP table, or default candidates, thereby resolving the availability issue while maintaining list construction efficiency

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different selection rules for different regions: for IBC blocks within MER, it uses a specialized selection process that excludes local MER candidates and relies on external candidates, while conventional merge candidate selection applies to other blocks. This localized quality adjustment ensures reliability without unnecessary complexity

Inventive Principle:

Principle #3Local quality

2Productivity

If conventional merge candidate list construction is used for IBC blocks in MER, then the process follows standard procedures, but coding efficiency is reduced due to unavailable spatial neighbouring blocks

Engineering Contradiction:

Improvecoding efficiencyVSAvoidloss of spatial neighbouring block information

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent uses the IBC HMVP (History-Based Motion Vector Prediction) table as a substitute source for BV candidates when spatial neighbouring blocks within MER are unavailable. This copying mechanism from historical data maintains coding efficiency by providing alternative reliable candidates without losing predictive capability

Inventive Principle:

Principle #26Copying

Solution Approach 2:

Instead of searching forward for spatial neighbouring block candidates as in conventional merge construction, the patent inverts the approach by searching backward in the IBC HMVP table and from outside the MER region, thereby recovering candidate information through an alternative information pathway

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS20250039375A1BV list construction process of IBC blocks under merge estimation region

Publication Date: 2025.01.30 BYTEDANCE INC

AI summary

BV list construction process of IBC blocks under merge estimation region is described. An example method of video processing includes determining, for a conversion between a current video block of a video and a bitstream of the video, one or more block vector (BV) candidates for the current video block based on a merge estimation region (MER) covering the current video block; adding the one or more BV candidates to a BV list associated with the current video block; and performing the conversion based on the BV list.