BVD Entropy Coding With Reduced Suffix Bits for Video Compression
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Solution Overview
Problem
Existing video coding techniques face inefficiencies in signaling overhead due to limitations in block vector difference (BVD) range, leading to unused codewords and suboptimal compression performance.
Innovation Solution
Implementing a method to select prefix and suffix parts of codewords for BVD entropy coding, reducing bit lengths and improving signaling efficiency by limiting the BVD range within a reference region, specifically for reconstruction-reordered intra block copy techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the range of BVD values is limited by limiting the reference region to a direction of flipping, then device complexity is reduced, but signaling overhead increases due to unused codewords in entropy coding
Solution Approach 1:
The patent changes the parameter of BVD range by introducing an extended reference region that allows BVD values beyond the traditional flipping direction limits. This enables more codewords to be utilized in entropy coding, reducing signaling overhead while maintaining manageable device complexity through structured extension of the reference region.
Solution Approach 2:
The patent segments the reference region into multiple parts: a primary reference region in the flipping direction and an extended reference region in additional directions. This segmentation allows flexible utilization of different reference blocks depending on the BVD value, optimizing both complexity and signaling efficiency.
2Loss of information
If the BVD range is extended beyond flipping direction limits, then signaling efficiency improves through reduced unused codewords, but device complexity increases
Solution Approach 1:
The patent modifies the BVD range parameter by allowing reference blocks from extended directions (not limited to flipping direction), thereby increasing the usable codeword space in entropy coding and improving signaling efficiency.
Solution Approach 2:
The patent introduces dynamic selection of reference blocks based on BVD value ranges. The encoder and decoder can adaptively choose from different reference regions (primary or extended) depending on the specific BVD being coded, optimizing signaling efficiency without requiring fixed complex structures.
Data Source
AI summary
A video parameter (e.g., a block vector difference (BVD)) may be represented as a codeword encoded using an entropy code. The codeword may comprising a prefix part and a suffix part. A prefix part may indicate a range of values, and a suffix part may indicate a specific value within the range. Efficient entropy coding may be achieved by reducing lengths of suffix parts associated with one or more selected prefix parts. The prefix parts may be selected based on a maximum possible value of the video parameter.