Intra-Prediction Mode Subsets for Lower Multi-Reference Signaling
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Solution Overview
Problem
Existing video coding techniques face inefficiencies due to increased signaling overhead when employing multiple reference lines for intra-prediction, leading to larger file sizes and decreased coding efficiency.
Innovation Solution
Implementing an intra-prediction mode subset that allows access to alternative reference lines only for certain modes, limiting others to a primary reference line, and optimizing reference line indexing based on selection probability to reduce signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple reference lines are employed for intra-prediction, then prediction accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent segments the intra-prediction modes into two distinct subsets: modes that utilize multiple reference lines and modes that utilize only a single reference line. This segmentation allows the system to selectively apply multiple reference lines only where beneficial, rather than universally applying them to all modes, thereby reducing overall signaling overhead while maintaining prediction accuracy where needed.
Solution Approach 2:
The patent implements partial action by limiting the application of multiple reference lines to only certain intra-prediction modes rather than all modes. By identifying specific modes that benefit from multiple reference lines and restricting their use to those cases, the system achieves improved prediction accuracy selectively without incurring the full signaling overhead that would result from universal application.
2Manufacturing precision
If multiple reference lines are used for all intra-prediction modes, then image quality is improved, but bitstream size increases
Solution Approach 1:
The patent divides intra-prediction modes into two categories: those that access multiple reference lines and those that access only a single reference line. This segmentation enables the system to maintain high image quality for modes where multiple reference lines provide benefit, while avoiding the bitstream size penalty for modes where a single reference line suffices.
Solution Approach 2:
The patent applies local quality by assigning different reference line configurations to different prediction modes based on their specific needs. Rather than uniformly applying multiple reference lines to all modes, the system tailors the reference line configuration to each mode's requirements, optimizing image quality where needed while minimizing bitstream size where simpler configurations suffice.
3Adaptability or versatility
If alternative reference lines are made available to all modes, then coding flexibility is improved, but device complexity increases
Solution Approach 1:
The patent segments the mode-reference line mapping into two distinct groups, simplifying the device's decision logic. Instead of evaluating all possible mode-reference line combinations, the device only needs to determine whether the current mode belongs to the subset that uses multiple reference lines or the subset that uses a single reference line, thereby reducing computational complexity while maintaining coding flexibility where needed.
Solution Approach 2:
The patent implements partial action by providing alternative reference lines to only certain modes rather than all modes. This selective approach reduces the complexity of reference line management and mode selection logic in the device, while still maintaining the flexibility to use multiple reference lines when they provide benefit for specific prediction modes.
Data Source
AI summary
A video coding device receives a bitstream including video data. The device determines an intra-prediction mode subset. The intra-prediction mode subset include intra-prediction modes that correlate to a plurality of reference lines for a current image block and excludes intra-prediction modes that correlate to a primary reference line for the current image block. When a first intra-prediction mode is included in the intra-prediction mode subset, the device decodes the first intra-prediction mode by an alternative intra-prediction mode index. When the first intra-prediction mode is not included in the intra-prediction mode subset, the device decodes the first intra-prediction mode by an intra-prediction mode index. The device presents video data including an image block decoded based on the first intra-prediction mode.