MVD Binarization Using Subset Coding for Better Compression
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Solution Overview
Problem
Current binary coding methods for Motion Vector Difference (MVD) absolute values in video coding fail to adapt to the distribution properties of these values, leading to suboptimal coding performance due to fixed codeword lengths and inefficient compression.
Innovation Solution
A method and apparatus for binary coding MVD absolute values by dividing them into subsets based on probability distribution properties, assigning consistent codewords within each subset, and concatenating prefix and postfix portions to optimize codeword length and adapt to source distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed length codewords are used for binary coding MVD absolute values, then the coding structure is simple, but the coding performance is suboptimal due to inability to adapt to distribution properties
Solution Approach 1:
The patent segments the binary coding process into two parts: a fixed prefix portion identifying the subset and a variable postfix portion encoding the symbol within the subset. This segmentation allows the system to maintain simple fixed-length prefix coding while adding adaptive variable-length postfix coding, thereby improving coding performance without completely redesigning the structure.
Solution Approach 2:
The patent introduces dynamic adaptation by dividing MVD absolute values into multiple subsets based on their probability distribution properties. Each subset has different coding characteristics, allowing the system to dynamically select the appropriate coding strategy (prefix + postfix) based on the actual distribution, thus adapting to different statistical patterns while maintaining overall structural simplicity.
2Device complexity
If fixed codeword lengths are used, then the coding method is simple, but compression efficiency is reduced due to excessive codeword lengths for low probability symbols
Solution Approach 1:
The patent applies local quality by assigning different codeword lengths to different symbols based on their local probability characteristics. High-probability symbols (typically in lower-numbered subsets) receive shorter combined prefix+postfix codewords, while low-probability symbols (in higher-numbered subsets) receive longer codewords. This localized adaptation to probability distribution significantly improves compression efficiency compared to uniform fixed-length coding.
3Productivity
If variable length codewords are assigned to all symbols, then compression efficiency improves, but the coding structure becomes complex
Solution Approach 1:
The patent segments the variable-length coding task into a fixed-length prefix component and a variable-length postfix component. The prefix uses fixed-length codewords to identify which subset the symbol belongs to, providing structural simplicity. The postfix then uses variable-length coding adapted to the specific subset's distribution, providing compression efficiency. This segmentation allows the system to achieve variable-length coding benefits without the full complexity of completely variable-length schemes.
Data Source
AI summary
A binary coding and decoding method and apparatus for MVD (Motion Vector Difference) absolute values, includes: dividing symbols for MVD absolute values to be coded into a plurality of subsets according to probability distribution properties; assigning a binary codeword for each subset; assigning a binary codeword for each symbol in each subset; concatenating and outputting the binary codeword for each subset and the binary codeword for each symbol in the subset, as the binary coding result. At the decoding side, decoding operations are performed by using a principle corresponding to that at the coding side. In this manner, the invention makes full use of the source properties on one hand, and effectively prevents the codeword length from being too long on the other hand. It has been experimentally testified that a better compression effect may be achieved during arithmetic coding process and thus the image coding performance may be improved effectively.