IBC Buffer Reset Using VPDUs for Boundary-Aware Video Coding
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Solution Overview
Problem
Existing video coding technologies face challenges in efficiently handling intra block copy (IBC) due to limitations in buffer management and reference block handling, particularly in scenarios where reference blocks are outside the picture boundaries or overlap with the current block, leading to inefficiencies and increased computational complexity.
Innovation Solution
The proposed solution involves a dynamic reference area management for IBC, using a virtual IBC buffer and pipeline data units (VPDUs) to optimize memory usage and reduce computational load, along with predictive coding techniques to enhance the efficiency of IBC operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional IBC buffer management approach is used, then the buffer can store reference blocks, but the buffer size becomes too large causing increased memory requirements and computational complexity
Solution Approach 1:
The patent divides the IBC buffer into multiple pipeline data units (VPDUs), each handling a specific portion of the buffer. This segmentation allows the system to manage reference blocks in smaller, more manageable units, reducing the overall buffer size requirement while maintaining the ability to store necessary reference blocks for IBC operations.
Solution Approach 2:
The patent introduces dynamic reference area management where the reference area is determined based on the current block position and size. The system dynamically adjusts which portions of the buffer are active and accessible, allowing efficient utilization of buffer space without requiring a fixed large buffer size, thus reducing memory requirements and complexity.
2Reliability
If the IBC buffer is reset for each video block, then the buffer is kept clean and ready for new reference blocks, but the computational load and processing time increase
Solution Approach 1:
The patent performs preliminary actions by determining the reference area and identifying which VPDU regions need to be reset before processing each video block. This allows the system to reset only the necessary portions of the buffer in advance, rather than resetting the entire buffer, thereby reducing computational load and processing time while ensuring the buffer is in the correct state for new reference blocks.
Solution Approach 2:
Instead of resetting the entire IBC buffer uniformly, the patent applies local quality by resetting only specific regions (VPDU regions) based on the current block's reference area requirements. This selective resetting approach maintains buffer integrity for active reference blocks while avoiding unnecessary computational operations on unused buffer regions, thus improving processing speed.
3Adaptability or versatility
If reference blocks outside picture boundaries or overlapping current blocks are handled, then IBC functionality is enhanced, but the computational complexity and errors increase
Solution Approach 1:
The patent performs preliminary determination of the reference area before processing each video block, calculating which regions of the buffer contain valid reference blocks based on the current block's position and size. This preliminary action allows the system to handle reference blocks outside picture boundaries or overlapping current blocks in a controlled manner, enhancing IBC functionality while preventing computational errors by clearly defining the valid reference area in advance.
Solution Approach 2:
The patent changes the parameter of reference area determination based on the current block's characteristics (position, size, and relationship to picture boundaries). By dynamically adjusting the reference area parameters, the system can adaptively handle various IBC scenarios including reference blocks outside picture boundaries or overlapping current blocks, enhancing versatility while managing computational complexity through parameter-based control.
Data Source
AI summary
Methods and an apparatus for video processing are described. One example method includes determining, for a conversion between a video block of a video and a bitstream of the video, that the video block satisfies a condition. The video block is coded in the bitstream using an intra block copy mode. The method further includes performing the conversion based on the determining. Here, due to the video block satisfying the condition, a portion of an intra block copy buffer is reset during the conversion.