Intra Block Copy With Adaptive BVD Precision for Video Compression
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Solution Overview
Problem
Existing video coding methods face inefficiencies in compressing video data due to high bit rate requirements and limited precision in encoding block vector differences, leading to suboptimal compression efficiency and increased signaling overhead.
Innovation Solution
Adaptive block vector difference (BVD) coding techniques that adjust precision based on the magnitude of the BVD, using lower precision for larger magnitudes to reduce signaling overhead while maintaining coding accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high precision is used to encode block vector difference (BVD), then coding accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent applies different precision levels to different BVD magnitude ranges. Small BVD magnitudes use high precision (e.g., 1/4 pixel) to maintain coding accuracy, while large BVD magnitudes use low precision (e.g., 1 pixel) to reduce signaling overhead. This local differentiation resolves the contradiction by optimizing precision usage based on the specific characteristics of each BVD.
Solution Approach 2:
The patent dynamically changes the precision parameter based on the BVD magnitude. By adjusting the pixel resolution parameter adaptively - using lower precision for large magnitudes and higher precision for small magnitudes - the system reduces overall signaling overhead while preserving necessary coding accuracy where it matters most.
2Ease of manufacture
If uniform precision is used for all BVD magnitudes, then implementation simplicity is maintained, but compression efficiency decreases
Solution Approach 1:
The patent introduces dynamic precision selection based on BVD magnitude thresholds. The system transitions from a static uniform precision approach to a dynamic adaptive approach where the precision level changes according to the actual BVD characteristics, thereby improving compression efficiency without significantly complicating the implementation through clear threshold-based decision logic.
3Loss of information
If low precision is used for large BVD magnitudes, then signaling overhead is reduced, but coding accuracy may be compromised
Solution Approach 1:
The patent applies differentiated precision strategies to different BVD magnitude regions. For large BVD magnitudes where absolute positioning is less critical, lower precision suffices and reduces signaling overhead. For small BVD magnitudes where precision matters more for accurate block matching, higher precision is applied to maintain coding accuracy.
Data Source
AI summary
An example method includes receiving a video bitstream comprising a plurality of blocks, including a current block. The method includes determining that the current block is intra coded based on a prediction block for the current block and a block vector (BV). When a block vector difference (BVD) is coded with an adaptive BVD pixel resolution: the method includes identifying one or more parameters of the BVD; and deriving the BVD based on the one or more BVD parameters. The method includes identifying the prediction block using the BV and the BVD; and reconstructing the current block using the prediction block.