Block Vector Video Coding With Residual Skip Copying
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Solution Overview
Problem
Existing video coding technologies face inefficiencies in handling residual coding for intra prediction modes, particularly in intra block copy (IBC) and intra template matching prediction (IntraTMP), leading to suboptimal compression and decoding performance.
Innovation Solution
Implementing a format rule that allows for direct copying of prediction block values when no residual related syntax element is signaled, using a block vector (BV) for intra block copy (IBC) and intra template matching prediction (IntraTMP) modes, and determining context-based skip flags for residual coding decisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If residual coding is applied to intra prediction blocks, then prediction accuracy is improved, but coding complexity and bitstream overhead increase
Solution Approach 1:
The patent introduces a skip flag parameter that changes the coding state between residual coding and direct copying. When the skip flag is set, the decoder skips residual decoding and directly copies prediction block values, dynamically adjusting the processing path based on the flag value without requiring complex decision logic at each decoding stage
Solution Approach 2:
Instead of always performing residual coding and then optionally applying skips, the patent inverts the approach by using the skip flag to determine whether to perform residual coding at all. When the skip flag indicates no residual coding, the decoder directly copies prediction values, effectively inverting the traditional workflow where residual coding is the default operation
2Measurement precision
If residual related syntax elements are signaled for all blocks, then decoding accuracy is improved, but bitstream overhead increases
Solution Approach 1:
The patent extracts the decision to signal residual syntax elements from the universal block processing flow and conditions it on the skip flag. When the skip flag is set, residual related syntax elements are not signaled, removing unnecessary data from the bitstream while preserving essential prediction information through the skip flag mechanism
Solution Approach 2:
The skip flag parameter dynamically controls whether residual syntax elements are included in the bitstream. This parameter change allows the encoder to adapt the bitstream content based on block characteristics, including residual syntax elements only when necessary for accurate reconstruction, thereby reducing overall bitstream overhead
3Productivity
If direct copying of prediction block values is used, then coding efficiency is improved, but prediction precision deteriorates
Solution Approach 1:
The patent makes the prediction method dynamic through the skip flag, allowing the system to switch between direct copying and residual coding based on block characteristics. This dynamic approach enables the encoder to select direct copying for blocks where it provides sufficient accuracy while using residual coding for blocks requiring higher precision, optimizing the trade-off between efficiency and precision on a per-block basis
Solution Approach 2:
The patent segments the video blocks into two categories based on the skip flag: blocks that use direct copying and blocks that use residual coding. This segmentation allows different processing strategies to be applied to different blocks, with direct copying applied to blocks where it is sufficient and residual coding applied where higher precision is needed, improving overall coding efficiency
4Productivity
If context-based skip flag determination is used, then compression performance is improved, but processing complexity increases
Solution Approach 1:
The patent implements self-service through context-based skip flag determination where the decoder uses locally available context information (such as neighboring block flags or block characteristics) to determine the skip flag value without requiring additional signaling from the encoder. This self-service mechanism improves compression by adapting to local block patterns while avoiding the complexity of explicit context signaling
Data Source
AI summary
Methods and apparatuses for video decoding and video encoding and a non-transitory computer-readable storage medium are described. The apparatus for video decoding includes processing circuitry configured to receive a bitstream that includes a syntax element. The syntax element indicates whether at least one residual related syntax element is signaled in the bitstream for a current block in a current picture when the current block is coded according to a prediction block in the current picture and an offset between the current block and the prediction block is indicated by a block vector (BV). When the syntax element indicates that no residual related syntax element is signaled, the processing circuitry is configured to reconstruct the current block by directly copying values of reconstructed samples in the prediction block.