PDPC Application Logic for Video Encoding Efficiency
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Solution Overview
Problem
Existing image encoding/decoding methods face challenges in achieving efficient encoding/decoding for high-resolution and high-quality images, leading to increased transmission and storage costs.
Innovation Solution
The proposed method involves an image decoding method that generates a prediction block through intra prediction on a current block, determines whether to apply position-dependent intra prediction combination (PDPC) based on the block size and reference sample line, and applies PDPC to the prediction block if the conditions are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-resolution and high-quality image encoding is performed, then image quality is improved, but transmission cost and storage cost increase
Solution Approach 1:
The patent applies PDPC (Position-Dependent Prediction Combination) which changes the prediction parameters dynamically based on the position of pixels within the block. By using different prediction combinations for different positions, the method achieves higher prediction accuracy for high-resolution images without proportionally increasing the bitstream size, thus improving image quality while controlling transmission cost
2Productivity
If PDPC is applied to improve prediction accuracy, then encoding efficiency is improved, but device complexity increases
Solution Approach 1:
The patent implements PDPC with different prediction combinations for different local positions within a prediction block. The method uses position-dependent weighting factors that vary based on the distance from block boundaries, allowing locally optimized prediction without requiring complex global processing. This local quality approach improves encoding efficiency while keeping the complexity manageable through systematic local calculations
3Measurement precision
If different PDPC conditions are used for luma and chroma blocks, then prediction accuracy is improved, but ease of operation deteriorates
Solution Approach 1:
The patent establishes unified PDPC application conditions that can be applied to both luma and chroma blocks. By using a universal threshold value (e.g., block size >= 4x4) and the same prediction combination methodology for all block types, the system maintains high prediction accuracy while significantly simplifying the determination process. The same algorithmic framework serves multiple functions for different color components
Data Source
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AI summary
An image encoding/decoding method and apparatus are provided. An image decoding method according to the present disclosure is performed by an image decoding apparatus. The image decoding method may comprise generating a prediction block by performing intra prediction on a current block, determining whether to apply position dependent intra prediction combination (PDPC) to the prediction block, and generating a final prediction block of the current block, by applying PDPC to the prediction block based on the determination. The determining whether to apply PDPC to the prediction block may comprise determining whether a size of the current block satisfies a predetermined condition. Based on the size of the current block satisfying the predetermined condition, it may be determined to apply PDPC to the prediction block. Based on the size of the current block doing not satisfy the predetermined condition, a determination of a color component of the current block may be skipped and it may be determined not to apply PDPC to the prediction block.