Intra Block Copy BVD Sign Indexing for Lower Bitrate
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Solution Overview
Problem
The existing methods for transmitting Block Vector Difference (BVD) signs in the Intra Block Copy (IBC) mode of H.266/Versatile Video Coding (VVC) are complex, leading to increased bitrate and reduced coding performance.
Innovation Solution
A decoding method that sorts candidate BVDs based on their absolute values and determines BVD sign index information, reducing bitrate by using adaptive probability models for BVD sign coding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If traditional methods are used to transmit BVD signs in IBC mode, then coding completeness is maintained, but transmission bitrate increases and coding performance deteriorates
Solution Approach 1:
The patent changes the parameter representation method by sorting candidate BVDs based on absolute values and using BVD sign index information to indicate the correct sign combination. This transforms the transmission from direct sign information to an indexed representation, reducing bitrate while maintaining coding completeness
Solution Approach 2:
The patent introduces an intermediary sorting mechanism that orders candidate BVDs by absolute value before transmission. This intermediary step allows the use of compact index information to represent BVD signs, reducing the complexity and bitrate of direct sign transmission
2Measurement precision
If BVD sign information is transmitted using existing methods, then accurate block vector prediction is achieved, but transmission bitrate increases
Solution Approach 1:
The patent changes how BVD parameters are encoded by using a sorted list of candidate BVDs with absolute values, and representing the actual BVD through an index into this sorted list. This parameter transformation maintains prediction accuracy while significantly reducing the bitrate required to transmit BVD sign information
3Adaptability or versatility
If complex transmission methods are used for BVD signs, then all sign combinations can be represented, but coding efficiency decreases
Solution Approach 1:
The patent transforms the BVD sign representation from direct encoding to an indexed representation based on sorted absolute values. This parameter change maintains the ability to represent all sign combinations while improving coding efficiency through more compact bitstream encoding
Solution Approach 2:
The patent performs preliminary sorting of candidate BVDs by absolute value before transmission. This preliminary action organizes the data in a way that enables more efficient encoding of BVD signs, improving coding efficiency while maintaining full representational capability
Data Source
AI summary
Provided are an encoding method and a decoding method. The decoding method includes: decoding a code stream to determine a BVD absolute value and BVD symbol index information of a current block; according to the BVD absolute value of the current block, sorting candidate BVDs of the current block to determine a sorting result; according to the BVD symbol index information and the sorting result, determining a BVD of the current block; and, according to the BVD of the current block, determining a reconstruction value of the current block. The encoding method includes: sorting candidate BVDs of a current block according to a BVD absolute value of the current block to determine a sorting result; according to BVD symbol information and the sorting result, determining BVD symbol index information of the current block; and writing the BVD absolute value and the BVD symbol index information into a code stream.