Video Decoding With MPM-Based Intra Prediction Mode Indexing
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Solution Overview
Problem
Existing video coding standards face challenges in achieving high coding efficiency for intra prediction due to increased signaling overhead from the expanded set of intra-prediction modes, which reduces overall coding efficiency.
Innovation Solution
Implement an improved decoding apparatus that utilizes a most probable mode (MPM) list to reduce signaling overhead by selecting the most likely intra-prediction modes for encoding and decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the set of intra-prediction modes is expanded to increase coding precision, then prediction accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent segments the intra-prediction modes into two categories: Most Probable Modes (MPM) and non-MPM modes. The MPM list contains the 6 most likely modes (indices 0-5) that are signaled with fewer bits, while other modes are signaled with more bits. This segmentation allows the system to prioritize signaling of high-probability modes, reducing overall signaling overhead while maintaining the ability to represent all 67 modes when necessary.
Solution Approach 2:
The patent changes the parameter representation by introducing an intra prediction mode coding scheme that uses a 6-entry MPM list. Instead of uniformly signaling all 67 modes with the same overhead, the system assigns different code lengths based on probability: modes in the MPM list use shorter codes (2 bits), while non-MPM modes use longer codes (5 bits). This parameter change optimizes the balance between prediction accuracy and signaling efficiency.
2Manufacturing precision
If more intra-prediction modes are signaled to improve coding efficiency, then reconstruction quality is improved, but bit rate increases
Solution Approach 1:
The patent segments the 67 intra-prediction modes into MPM modes (6 modes with indices 0-5) and non-MPM modes (61 modes with indices 6-66). This segmentation enables differential signaling where the majority of commonly used modes consume fewer bits, thereby reducing the average bit rate while preserving the capability to represent all modes for high reconstruction quality when needed.
Solution Approach 2:
The patent implements a variable-length coding scheme for intra prediction modes based on their probability of occurrence. MPM modes are encoded with 2 bits while non-MPM modes use 5 bits. This parameter change in code length allocation reduces the expected bit rate by exploiting the statistical distribution of mode usage, while maintaining full representation capability for high-quality reconstruction.
Data Source
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AI summary
The invention relates to a method of decoding implemented by a decoding device, comprising: obtaining a value of a reference line index for a current block; constructing a most probable mode, MPM, list for the current block; obtaining a value of intra-prediction mode index for the current block; when the value of the reference line index is not equal to 0, obtaining an intra prediction mode of the current block according to the MPM list for the current block and the value of the intra-prediction mode index for the current block, wherein the value of the intra-prediction mode index indicates a position, the position is corresponded to the intra prediction mode of the current block among angular intra-prediction modes in the MPM list. The invention also relates to an apparatus and a computer program product.