Image Decoding with Scaled Chroma Intra-Prediction Modes
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Solution Overview
Problem
The existing MPEG-4 AVC/H.264 coding system faces inefficiencies in coding and decoding processes due to the lack of direct consideration for color-difference formats, particularly in intra-prediction mode coding, which affects process efficiency.
Innovation Solution
A picture coding device and method that sets prediction blocks for both brightness and color-difference signals, using intra-brightness and intra-color-difference prediction modes to efficiently code and decode signals based on color-difference formats, allowing for optimized bitstream management and prediction within conversion blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If intra-prediction mode is coded without considering color-difference format, then coding process is simplified, but process efficiency is degraded
Solution Approach 1:
The patent applies local quality by differentiating the intra-prediction coding process based on color-difference format. When color-difference format is 4:4:4, the patent codes intra-prediction mode separately for brightness and color-difference signals, whereas for other formats it uses unified coding. This localized adaptation to specific conditions optimizes process efficiency without unnecessarily complicating the general case.
2Manufacturing precision
If separate intra-prediction modes are used for brightness and color-difference signals, then coding precision is improved, but device complexity increases
Solution Approach 1:
The patent implements a dynamic coding mechanism that adapts the intra-prediction mode coding strategy based on the color-difference format. The system dynamically switches between unified coding (for 4:2:0, 4:2:2 formats) and separate coding (for 4:4:4 format), allowing it to achieve high coding precision when needed while maintaining simplicity for other cases. This dynamic adaptation resolves the contradiction between precision and complexity.
Data Source
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AI summary
In a picture coding device for coding picture signals including a brightness signal and a color-difference signal in a block unit using intra-prediction and coding information regarding an intra-prediction mode, when aspect ratios of pixels of the brightness signal and the color-difference signal are different from each other, a bitstream generator 113 converts a mode number of a first intra-color-difference prediction mode used when the aspect ratios are equal to each other into a scaled mode number and derives a second intra-color-difference prediction mode used when the aspect ratios are different from each other.