Intra-Inter Prediction Mode Using Position-Dependent Intra Prediction Combination
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Solution Overview
Problem
Current video coding technologies, such as those used in H.265/HEVC and proposed in VVC, face challenges with complexity, memory usage, and suboptimal weighting factors in intra-inter prediction modes.
Innovation Solution
The proposed solution involves a method and apparatus that utilize position-dependent intra prediction combination (PDPC) to modify inter prediction samples and reconstructed samples of inter-coded coding units (CUs), with specific weighting factors and filtering techniques applied to improve prediction accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If position-dependent intra prediction combination (PDPC) is applied to modify inter prediction samples, then prediction accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent applies PDPC selectively based on block size and neighboring block types. Different weighting factors are used for different block sizes (e.g., 4x4, 8x8, 16x16, 32x32), and the application of PDPC is controlled by flags that depend on whether neighboring blocks are intra-coded or inter-coded. This localized application reduces overall computational complexity while maintaining prediction accuracy where it matters most.
Solution Approach 2:
The patent implements a simplified version of PDPC that applies only to inter-coded blocks with specific characteristics. Instead of applying full PDPC to all blocks, the method uses conditional flags (interPDPCFlag, interPDPCFilterFlag) to apply partial PDPC processing only when beneficial, reducing computational load while achieving sufficient prediction accuracy.
2Measurement precision
If multiple weighting factors are optimized for different block sizes, then prediction accuracy is improved, but device complexity increases
Solution Approach 1:
The patent defines different weighting factor sets for different block sizes. For example, w0 and w1 are calculated differently based on whether the block is 4x4, 8x8, 16x16, or 32x32. The weighting factors are adjusted according to block dimensions, allowing optimization for each size while using a systematic approach that manages complexity through parameterization rather than completely separate processing paths.
3Measurement precision
If PDPC filters are applied before in-loop deblocking filters, then prediction accuracy is improved, but processing time increases
Solution Approach 1:
The patent applies PDPC filters in the early stage of the filtering process, before in-loop deblocking filters. The sequence is: inter prediction → PDPC filtering → in-loop deblocking. This preliminary application of PDPC ensures that prediction samples are refined before subsequent deblocking operations, improving overall prediction accuracy while maintaining an efficient processing pipeline.
Data Source
AI summary
An improved scheme for intra-inter prediction mode and an adaptive intra-inter prediction mode for video coding/decoding, including selecting a set of weightings in an intra-inter mode and applying position dependent intra prediction combination to modify at least one of an inter prediction sample and another sample.