Hash-Based Block Matching for Video Coding Efficiency
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Solution Overview
Problem
The existing HEVC standard's intra block copy prediction mode lacks effective encoder-side decision-making processes, leading to inefficiencies in video encoding.
Innovation Solution
The implementation of hash-based block matching, where encoders use hash values to identify matching blocks for encoding and decoders use signaled hash values for reconstruction, improving both rate-distortion performance and computational efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional block matching methods are used in intra block copy prediction, then encoding accuracy can be maintained, but computational complexity increases significantly
Solution Approach 1:
The patent extracts only the essential features of blocks (hash values) rather than comparing complete block data. By computing hash values for candidate blocks and comparing these compact representations, the method maintains encoding accuracy while dramatically reducing computational complexity compared to traditional full-block matching approaches.
Solution Approach 2:
The patent transforms the block matching problem from comparing raw pixel data to comparing hash value parameters. This parameter transformation enables efficient comparison operations while preserving the ability to identify matching blocks, thus resolving the contradiction between accuracy and computational complexity.
2Manufacturing precision
If exhaustive block search is performed to ensure accurate matching, then prediction quality improves, but encoding time increases
Solution Approach 1:
The patent performs preliminary hashing of candidate blocks before the actual matching process. By pre-computing and storing hash values for all candidate blocks, the method enables rapid identification of matching blocks during encoding, significantly reducing encoding time while maintaining prediction quality through accurate block matching.
Solution Approach 2:
The patent introduces hash values as an intermediary representation between the original block data and the matching decision. This intermediary enables efficient comparison and identification of matching blocks without requiring exhaustive search of the entire candidate block set, thus reducing encoding time while preserving prediction accuracy.
3Measurement precision
If more candidate blocks are evaluated for matching, then matching accuracy improves, but computational load increases
Solution Approach 1:
The patent extracts hash values from candidate blocks as compact representations that enable efficient comparison. By working with these extracted features rather than complete block data, the method can evaluate more candidate blocks with the same computational resources, thus improving matching accuracy without proportionally increasing computational load.
Data Source
AI summary
Innovations in hash-based block matching facilitate block copy (“BC”) prediction that is more effective in terms of rate-distortion performance and/or computational efficiency of encoding. For example, some of the innovations relate to encoding blocks with hash values determined using hash-based block matching. Other innovations relate to reconstructing blocks using hash values determined with hash-based block matching.