Current Picture Referencing with QTBT for Screen Content Coding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current video coding technologies face limitations in efficiently utilizing spatial correlation within the same picture for screen content, particularly in HEVC, due to difficulties in finding exact matches for block matching and copy techniques, which restricts coding performance.
Innovation Solution
The implementation of Current Picture Referencing (CPR) mode using a quad-tree plus binary tree (QTBT) structure and luma/chroma separate coding, where luma and chroma components are jointly or separately partitioned using a common coding unit structure, with motion vectors adapted for each component to enhance prediction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If block matching and copy techniques are used in HEVC, then temporal prediction is achieved, but spatial correlation within the same picture cannot be efficiently utilized
Solution Approach 1:
The picture is divided into multiple blocks that can be independently referenced. The patent segments the current picture into reference blocks that can be used for prediction, allowing different regions to be referenced separately. This enables efficient utilization of spatial correlation by creating multiple reference points within the same picture.
Solution Approach 2:
The patent introduces a new dimension for reference by allowing blocks within the same picture to reference each other spatially, rather than only using temporal references from previous pictures. This creates a two-dimensional reference structure (spatial and temporal) that efficiently captures spatial correlation while maintaining temporal prediction capabilities.
2Adaptability or versatility
If luma and chroma components are coded separately, then coding flexibility is improved, but coding efficiency is reduced
Solution Approach 1:
The patent merges the reference block selection process for luma and chroma components, allowing them to share common reference blocks and motion vectors. This combining approach maintains the flexibility of separate coding while improving efficiency by reducing redundancy in reference management and enabling joint optimization of both components.
3Ease of manufacture
If fixed block partitioning is used, then processing simplicity is maintained, but coding performance is limited
Solution Approach 1:
The patent introduces dynamic block partitioning where block sizes and shapes can adapt to the content being coded. The partitioning structure can dynamically adjust to match edges and boundaries in the image, improving coding performance while maintaining reasonable processing complexity through systematic partitioning rules.
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
A method and apparatus for a video coding system with the current picture referencing (CPR) mode enabled are disclosed. According to one method, the luma and chroma blocks of the current image are jointly coded using a same coding unit (CU) structure if the CPR mode is selected for the luma and the chroma blocks. Alternatively, if the luma and chroma components are partitioned into the luma and the chroma blocks separately using separate CU structures, the luma and chroma blocks are encoded or decoded using a coding mode selected from a coding mode group excluding the CPR mode. According to another method, the luma and chroma blocks of the current image are coded separately using a different CU structure if the CPR mode is selected for the luma and chroma blocks. In yet another method, reconstructed reference data is disclosed for the CPR mode with CU equal to PU.