Intra Block Copy Search Range Optimization
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Solution Overview
Problem
Existing video coding technologies face challenges in efficiently encoding and decoding video data, particularly in reducing redundancy and managing large bandwidth and storage requirements.
Innovation Solution
The proposed solution involves an apparatus for video decoding that processes circuitry to decode prediction information from a coded video bitstream, indicating an intra block copy mode. It determines whether a current block should be reconstructed first in its region and calculates a block vector to find a reference block within a search range that excludes a collocated region in a previously reconstructed CTB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the search range for intra block copy includes the entire previously reconstructed CTB, then more reference blocks are available for prediction, but memory requirements and processing complexity increase
Solution Approach 1:
The patent segments the previously reconstructed CTB into multiple regions and selectively includes only certain regions in the search range for intra block copy. This segmentation approach maintains adequate reference block availability while reducing the overall search range size, thereby lowering memory requirements and processing complexity.
Solution Approach 2:
The patent applies different search range inclusion criteria to different regions of the previously reconstructed CTB. Certain regions are included in the search range while others are excluded based on their relevance to the current block being encoded, optimizing the balance between reference block availability and computational efficiency.
2Device complexity
If the search range excludes the collocated region to reduce memory access, then memory requirements decrease, but prediction accuracy may deteriorate
Solution Approach 1:
The patent performs preliminary determination of which regions to include in the search range before the actual encoding process. By pre-identifying relevant regions and excluding the collocated region where possible, the system prepares an optimized search range that balances memory access efficiency with prediction accuracy requirements.
Solution Approach 2:
The patent dynamically adjusts the search range parameters based on the current block position and previously reconstructed regions. By changing the search range boundaries and inclusion criteria, the system optimizes the trade-off between memory access requirements and prediction accuracy for different encoding scenarios.
3Productivity
If intra block copy is used to reduce redundancy, then compression ratio improves, but encoding complexity increases
Solution Approach 1:
The patent applies intra block copy selectively to only certain blocks that benefit most from this mode, rather than applying it universally. By using partial action (selective application), the system achieves compression benefits where needed while avoiding the full encoding complexity overhead across all blocks.
Solution Approach 2:
The patent changes the encoding mode parameter dynamically based on block characteristics and search results. By adjusting whether to apply intra block copy mode on a per-block basis, the system optimizes the balance between compression ratio improvement and encoding complexity management.
Data Source
AI summary
A method and an apparatus for video decoding are disclosed. The apparatus includes processing circuitry that decodes prediction information of a current block that is indicative of an intra block copy mode. The current block is in a current region of a plurality of regions of a current coding tree unit (CTU) in a current picture. The processing circuitry determines a block vector for the current block, a reference block indicated by the block vector being in a search range that excludes at least a region in a previously reconstructed CTU that is collocated with the current region of the current CTU, a position of the collocated region in the previously reconstructed CTU having a same relative position as the current region in the current CTU, the search range being in the current picture. The processing circuitry reconstructs at least one sample of the current block according the block vector.