Intra Prediction Mode Coding with Separate DC and Planar Indices
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Solution Overview
Problem
Current video coding standards, such as HEVC, face inefficiencies in intra prediction mode coding due to dependent coding of DC and Planar modes, which degrades coding performance.
Innovation Solution
Assigning individual indices, codewords, and binarized representations for DC and Planar modes, and using separate context-adaptive entropy coding tables to improve prediction and encoding efficiency by exploiting correlations between neighboring blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If DC and Planar modes share one mode index and codeword to reduce signaling overhead, then device complexity is reduced, but coding performance deteriorates due to inability to exploit their different statistical characteristics
Solution Approach 1:
The patent segments the mode indexing system by assigning separate mode indices to DC mode and Planar mode instead of sharing a single index. This allows independent entropy coding tables to be used for each mode, exploiting their different statistical characteristics and improving coding performance while maintaining reasonable signaling overhead through the use of Most Probable Mode (MPM) prediction mechanisms.
2Reliability
If more most probable modes are used to improve coding efficiency, then coding performance improves, but device complexity increases due to larger coding tables and processing requirements
Solution Approach 1:
The patent applies local quality by creating different entropy coding tables tailored to specific mode characteristics. Separate tables are designed for DC mode and Planar mode based on their individual statistical properties, allowing optimized coding for each mode type without requiring excessively large universal tables, thus balancing coding efficiency with manageable complexity.
Data Source
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AI summary
Method and apparatus for intra prediction mode coding and decoding are disclosed. In one embodiment, the encoding and decoding process assigns individual indices and codewords to DC mode and Planar mode respectively. The flag is set if the current intra prediction mode is equal to any of one or more neighboring intra prediction modes. Variable length codes are designed for a remaining mode set. If the flag is not set, the currently intra prediction mode is encoded using the variable length codes. In another embodiment, multiple most probable modes are used. If the current intra prediction mode is not equal to any of the multiple most probable modes, the current intra prediction mode is encoded using variable length codes designed for the corresponding remaining modes according the ranking order of the remaining modes.