Video Coefficient Parity for Sign Bit Hiding
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Solution Overview
Problem
Current video encoding standards, such as H.264/AVC and developing HEVC, face inefficiencies in encoding and decoding transform coefficients, particularly in hiding sign bits and other information bits, which can result in unacceptable distortion and increased data volume.
Innovation Solution
The method involves using partially overlapping subsets of coefficients to hide multiple sign bits or other information bits, allowing for correct parity results with minimal adjustments to coefficient values, thereby reducing distortion and optimizing bitstream efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If traditional encoding methods are used to encode quantized transform coefficients, then the encoding process is simple and straightforward, but the bitstream occupies 30-80% of the encoded data and results in unacceptable distortion
Solution Approach 1:
The patent extracts and hides sign bits from the traditional encoding process by utilizing parity information from coefficient sets. Instead of explicitly encoding each sign bit, the method extracts sign information from the parity of coefficient sums, thereby reducing the bitstream size while maintaining encoding functionality.
Solution Approach 2:
The patent makes the coefficient sets serve multiple functions: they not only represent transform coefficients but also carry hidden sign bit information through their parity. This multi-functionality allows the same data structure to serve both as coefficient representation and as carrier for sign information, reducing overall data volume.
2Loss of information
If sign bits are hidden using parity of coefficient sets, then the bitstream size is reduced, but distortion increases when coefficient adjustments are required
Solution Approach 1:
The patent applies partial action by adjusting only a subset of coefficients (specifically, modifying the parity of coefficient sums) rather than adjusting all coefficients. This selective adjustment approach minimizes the impact on overall coefficient accuracy while still achieving the sign bit hiding objective.
Solution Approach 2:
The patent changes the parameter approach by instead of changing individual coefficient values to hide sign bits, it modifies the parity parameter of coefficient sums. This parameter change approach allows sign bit hiding while preserving individual coefficient values as much as possible, thereby maintaining coefficient accuracy.
3Productivity
If multiple sign bits are hidden using overlapping subsets, then encoding efficiency is improved, but the complexity of determining and adjusting coefficients increases
Solution Approach 1:
The patent segments the coefficient sets into overlapping subsets, where each subset contributes to hiding specific sign bits. This segmentation allows multiple sign bits to be hidden simultaneously using a systematic approach, improving encoding efficiency while managing complexity through structured processing.
Solution Approach 2:
The patent applies preliminary action by pre-determining the parity relationships between coefficient sets before the actual encoding process. This preliminary setup of parity information allows the encoding to proceed more efficiently without requiring complex real-time calculations, thus improving productivity while controlling processing complexity.
Data Source
AI summary
Methods and devices for reconstructing coefficient levels from a bitstream of encoded video data for a coefficient group in a transform unit. Sign bits are hidden in the parity of partially overlapping subsets of a set of coefficients. This enables the hiding of multiple sign bits per coefficient group. Other information bits may be hidden instead of sign bits in some cases.