Intra Block Copy Prediction with Constrained Reference Search
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Solution Overview
Problem
The increasing size, resolution, and frame rate of video data necessitate improved compression techniques with better encoding efficiency and higher image quality than existing methods like H.264/AVC and HEVC.
Innovation Solution
A video encoding and decoding method that utilizes intra block copy (IBC) mode, limiting the reference block within a defined search area to improve compression performance by predicting blocks within equal-sized coding tree units, and managing a search range to find matching blocks within a picture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the search area for finding a reference block is expanded to improve prediction accuracy, then encoding efficiency improves, but the complexity of the encoding process increases
Solution Approach 1:
The current coding tree block is divided into multiple processing regions, and the search area is segmented into specific regions (current block, left block, above block) with different priorities. This segmentation allows the encoder to systematically search through divided regions rather than treating the entire block as one search space, improving efficiency while maintaining manageable complexity
Solution Approach 2:
The patent establishes predetermined search priorities and regions before the actual search process begins. Processing regions are pre-defined (current, left, above blocks) with specific search orders, allowing the encoder to prepare the search framework in advance and execute the search more efficiently without ad-hoc decision-making during encoding
2Manufacturing precision
If the block vector range is increased to allow more flexible reference block selection, then prediction accuracy improves, but the risk of selecting invalid reference blocks increases
Solution Approach 1:
Different regions within the coding tree block are assigned different qualities or priorities for reference block selection. The current block, left block, and above block are treated as distinct regions with different search priorities. This local differentiation allows the system to preferentially select reference blocks from more reliable regions while still permitting searches in broader areas when needed
Solution Approach 2:
The patent introduces processing regions as intermediary zones between the current block and potential reference blocks. These processing regions act as buffers that organize and filter the search space, ensuring that reference blocks are selected from valid, pre-processed areas while maintaining flexibility in the search range
3Productivity
If more processing regions are included in the search area to improve reference block selection, then encoding efficiency improves, but the memory resources required increase
Solution Approach 1:
The patent implements a prioritized search approach where only necessary processing regions are searched based on prediction needs. The search starts with the current block and left block (most relevant regions), and only extends to above blocks or other regions if prediction accuracy requirements are not met. This partial action approach achieves good encoding efficiency without requiring all possible regions to be fully processed and stored in memory
Data Source
AI summary
A video decoding method for predicting a picture, which is split into equal-sized coding tree blocks, in units of blocks, the method includes: reconstructing a block vector for a current coding block in a current coding tree block to be decoded, by decoding block vector information from a bitstream, wherein the current coding block is one of blocks split from the current coding tree block in a tree structure; and setting, as a prediction block of the current coding block, a reference block indicated by the block vector in the picture in which the current coding block is located.