Intra Block Copy Vector Signaling for Video Coding Efficiency
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Solution Overview
Problem
Current video encoding and decoding technologies face inefficiencies in intra Block Copy (BC) block vector coding, particularly in removing redundancies and improving coding efficiency for screen content, due to limitations in signaling and inferring syntax elements for block vector differences.
Innovation Solution
The proposed techniques conditionally signal and infer syntax elements representing the absolute value and sign of block vector difference components, allowing for improved decoding of video data using intra BC mode by determining block vectors and predictors, thereby enhancing coding efficiency and reducing redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If syntax elements representing absolute value and sign of block vector difference components are always signaled, then decoding accuracy is improved, but bit rate increases
Solution Approach 1:
The patent applies partial action by conditionally signaling syntax elements. Instead of always signaling both absolute value and sign for all block vector difference components, the encoder selectively signals only when necessary based on prediction modes and component characteristics, reducing bit rate while maintaining decoding accuracy where critical
Solution Approach 2:
The patent extracts and removes redundant information by inferring the sign of the second component from the first component's sign in certain prediction modes. This extraction of redundant sign information reduces the bit rate without sacrificing decoding accuracy, as the inferred sign is sufficient for correct reconstruction
2Quantity of substance
If syntax elements are conditionally signaled based on prediction modes, then bit rate is reduced, but decoder complexity increases
Solution Approach 1:
The patent applies preliminary action by establishing clear syntax element signaling rules and inference conditions in advance based on prediction modes. The decoder uses pre-defined logic to determine when to expect signaled values and when to infer values, reducing runtime complexity through predetermined decision pathways
Solution Approach 2:
The patent applies local quality by treating different block vector difference components differently based on their characteristics and prediction modes. The first component may be fully signaled while the second component uses inference, creating localized optimization strategies that reduce overall bit rate without uniformly increasing complexity across all components
3Productivity
If inference of second sign value is implemented, then coding efficiency is improved, but reliability may be reduced when inference assumptions are violated
Solution Approach 1:
The patent applies dynamics by making the signaling strategy adaptive to different prediction modes and component characteristics. The encoder dynamically selects whether to signal or infer based on the specific prediction mode being used, ensuring that inference is only applied when the underlying assumptions are valid for that mode, thus maintaining reliability while improving coding efficiency
Data Source
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AI summary
This disclosure describes techniques for coding video data according to an intra Block Copy (BC) coding mode. A block vector difference that identifies a prediction block may be represented by a plurality of syntax elements, which may be encoded and decoded. This disclosure proposes various techniques whereby a video encoder may conditionally signal syntax elements representing the absolute value and/or sign of the components of the block vector difference. Likewise, a video decoder may be configured to infer the values of the syntax elements representing the absolute value and/or sign of the components of the block vector difference when such syntax elements are not signaled.