Intra Block Copy Search Range for Overwrite-Aware Video Decoding
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Solution Overview
Problem
Existing video coding technologies face inefficiencies in intra block copy (IBC) processes, particularly in determining when to overwrite reconstructed samples in memory, leading to suboptimal compression and decoding performance.
Innovation Solution
The proposed solution involves processing circuitry that determines whether reconstructed samples of a reference sub-block in memory are indicated as overwritten based on the position of a current sub-block, generating reconstructed samples for the current sub-block when they are not overwritten, and overwriting collocated sub-blocks in the reconstructed block accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the search range for intra block copy is extended to improve compression ratio, then the compression performance improves, but the computational complexity and processing time increase
Solution Approach 1:
The search range is divided into multiple candidate regions based on partition boundaries. Instead of searching the entire extended area, the algorithm segments the search space into manageable parts (e.g., upper-left, upper-right, lower-left, lower-right regions relative to partition boundaries), evaluating only specific candidate blocks within these segments. This reduces computational complexity while maintaining compression performance.
Solution Approach 2:
The patent performs preliminary identification of candidate reference blocks based on their positional relationship with partition boundaries before conducting the full IBC process. By pre-filtering candidates that satisfy specific boundary conditions, the algorithm reduces the number of blocks requiring detailed evaluation, thereby lowering computational complexity while preserving compression effectiveness.
2Loss of substance
If the search range for intra block copy is extended to improve compression ratio, then the compression performance improves, but the processing time increases
Solution Approach 1:
The extended search range is segmented into distinct candidate regions defined by partition boundaries. The algorithm processes only specific segments (e.g., blocks in certain directional relationships to partition edges) rather than evaluating all blocks in the extended area, significantly reducing processing time while maintaining compression ratio improvements.
Solution Approach 2:
The patent applies partial action by evaluating only a subset of candidate blocks that meet specific boundary-based criteria, rather than exhaustively searching the entire extended search range. This selective approach achieves sufficient compression improvement without the full processing cost of a complete extended search.
3Productivity
If the memory overwrite determination is optimized to improve encoding efficiency, then the encoding speed improves, but the memory management complexity increases
Solution Approach 1:
The patent applies different overwrite determination rules based on the local position of blocks relative to partition boundaries. Instead of using a uniform memory management approach, the algorithm adjusts overwrite behavior locally depending on whether blocks are adjacent to partition edges and their directional relationships, improving encoding efficiency while keeping memory management complexity manageable through localized decision-making.
Solution Approach 2:
The algorithm performs preliminary determination of memory overwrite status based on block positions relative to partition boundaries before actual memory operations. By pre-identifying which blocks will be overwritten and which serve as valid reference blocks, the system optimizes encoding efficiency while maintaining clear memory management through advance planning of memory operations.
Data Source
AI summary
In a method for video decoding in a decoder, reconstructed samples of a reconstructed block of a picture are stored. When a current sub-block in a current block of the picture is to be reconstructed using intra block copy (IBC) based on a reference sub-block in the reconstructed block, the reference sub-block for the current sub-block is identified, whether the reconstructed samples of the reference sub-block stored are indicated as overwritten is determined based on a position of the current sub-block, reconstructed samples of the current sub-block for output are generated based on the reconstructed samples of the reference sub-block when the reconstructed samples of the reference sub-block stored are determined to be indicated as not overwritten, and the reconstructed samples of a collocated sub-block in the reconstructed block stored are overwritten with the generated reconstructed samples of the current sub-block.