MPM List Derivation for Video Coding Using Predefined Intra Modes
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Solution Overview
Problem
Current video coding standards, such as HEVC and emerging VVC, face challenges in efficiently deriving the most probable mode (MPM) list for Intra prediction, particularly in handling diverse video content like natural videos and screen content, where spatial correlation within the same picture is complex, limiting coding performance.
Innovation Solution
The method involves deriving an MPM list based on predefined Intra modes for neighboring blocks, considering conditions like Inter mode, IBC, BDPCM, and prediction directions, to assign appropriate Intra modes for luma and chroma blocks, and using flowcharts to implement these steps in video decoding and encoding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional MPM list derivation methods are used for Intra prediction, then the coding process is simple, but coding efficiency is limited due to inability to handle diverse video content effectively
Solution Approach 1:
The patent implements dynamic MPM list derivation by adapting the list composition based on the prediction mode of neighboring blocks. When neighboring blocks use Inter mode, IBC, or BDPCM, the MPM list is constructed with specific default modes (Planar, DC, Vertical, Horizontal) rather than using conventional angular mode derivations. This dynamic adaptation allows the system to handle diverse video content (natural videos, screen content) effectively while maintaining reasonable processing complexity.
Solution Approach 2:
The patent changes the parameters of the MPM list by assigning specific predefined Intra modes (Planar mode index 0, DC mode index 1, Vertical mode index 50, Horizontal mode index 18) based on neighboring block characteristics. This parameter change strategy improves coding efficiency for different video content types by selecting appropriate default modes rather than using fixed derivation rules.
2Measurement precision
If predefined Intra modes are assigned to neighboring blocks based on their prediction modes, then coding accuracy improves, but the processing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining the MPM list composition based on the prediction modes of neighboring blocks before actual prediction. When a neighboring block is identified as using Inter mode, IBC, or BDPCM, the system pre-assigns appropriate default Intra modes (Planar, DC, Vertical, or Horizontal) to the MPM list. This preliminary configuration improves derivation accuracy while keeping the processing complexity manageable through rule-based assignments.
Data Source
AI summary
Method and apparatus of video coding are disclosed. According to one method, in the decoder side, a predefined Intra mode is assigned to a neighboring block adjacent to the current luma block when the neighboring block satisfies one or more conditions. An MPM (Most Probable Mode) list is derived based on information comprising at least one of neighboring Intra modes. A current Intra mode is derived utilizing the MPM list. The current luma block is decoded according to the current Intra mode According to another method, a predefined Intra mode is assigned to a neighboring block adjacent to the current luma block if the neighboring block is coded in BDPCM (Block-based Delta Pulse Code Modulation) mode, where the predefined Intra mode is set to horizontal mode or vertical mode depending on prediction direction used by the BDPCM mode.