Intra Block Copy Search Range Adjustment for Video Decoding
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Solution Overview
Problem
Existing video coding technologies face challenges in efficiently encoding and decoding video data, particularly in reducing redundancy and managing large data sizes, while maintaining acceptable distortion levels.
Innovation Solution
The proposed solution involves an apparatus and method for video decoding that includes receiving and processing circuitry to decode prediction information for a current block within a current coding tree unit (CTU) from a coded video bitstream. This involves determining a block vector pointing to a reference block in the same picture, with reconstructed samples buffered in a reference sample memory, and reconstructing at least one sample of the current block based on the reference block samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If intra block copy mode is used with full reference sample memory, then coding performance is improved, but memory requirements increase
Solution Approach 1:
The patent applies local quality by adjusting the search range for intra block copy based on the current CTU size. Instead of using a uniform full reference sample memory for all CTUs, the search range is locally adapted to match the actual CTU dimensions, allocating memory resources proportionally to local needs rather than uniformly across the entire picture.
Solution Approach 2:
The patent implements dynamics by making the reference sample memory search range variable rather than fixed. The search range dynamically adjusts according to the current CTU size, allowing the system to optimize memory usage based on the actual processing requirements of each coding unit, thereby improving coding efficiency while reducing unnecessary memory allocation.
2Productivity
If variable CTU sizes are used, then coding efficiency is improved, but search range adjustment complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the search range parameters according to the current CTU size. The search range is adjusted as a function of the CTU dimensions, allowing the system to handle variable CTU sizes efficiently by changing the search range parameter to match the actual coding unit being processed.
3Adaptability or versatility
If full reference sample memory is allocated, then all reference blocks are accessible, but memory bandwidth consumption increases
Solution Approach 1:
The patent extracts only the necessary portion of the reference sample memory that is needed for the current CTU processing. By taking out only the relevant reference blocks within the adjusted search range rather than accessing the full reference sample memory, the system reduces memory bandwidth consumption while maintaining access to all necessary reference data for accurate intra block copy coding.
Data Source
AI summary
Aspects of the disclosure provide methods and apparatuses for video encoding/decoding. In some examples, an apparatus for video decoding includes receiving circuitry and processing circuitry. For example, the processing circuitry decodes prediction information of a current block in a current coding tree unit (CTU) from a coded video bitstream. The prediction information is indicative of an intra block copy mode. A size of the current CTU is smaller than a maximum size of a reference sample memory for storing reconstructed samples. The processing circuitry determines a block vector that points to a reference block in a same picture as the current block. The reference block has reconstructed samples buffered in the reference sample memory. Then, the processing circuitry reconstructs at least a sample of the current block based on the reconstructed samples of the reference block that are retrieved from the reference sample memory.