MPM List Generation for Video Intra Prediction
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Solution Overview
Problem
Existing video coding technologies, such as HEVC and VVC, face complexity in generating most probable modes (MPMs) lists for intra prediction, particularly when dealing with zero and non-zero reference lines, which can lead to inefficiencies in coding efficiency and increased computational complexity.
Innovation Solution
A method is proposed to simplify the generation of MPMs lists by signaling a reference line index and an intra mode index, where the MPMs lists for zero and non-zero reference lines include a plurality of angular intra prediction modes, allowing for efficient encoding of current blocks in video bitstreams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate MPM lists are generated for zero and non-zero reference lines, then prediction accuracy is improved, but device complexity increases
Solution Approach 1:
The patent divides the MPM list generation into two separate lists: one for zero reference lines and another for non-zero reference lines. This segmentation allows each list to be optimized for its specific reference line type, improving prediction accuracy while managing complexity through structured organization
Solution Approach 2:
The patent dynamically selects which MPM list to use based on the reference line index. When the reference line index indicates a zero reference line, the first MPM list is used; otherwise, the second MPM list is used. This dynamic selection adapts the complexity to the specific case, improving accuracy when needed while avoiding unnecessary complexity when not required
2Device complexity
If simplified MPM list generation is used, then device complexity is reduced, but coding efficiency deteriorates
Solution Approach 1:
The patent pre-generates two MPM lists with different compositions tailored for zero and non-zero reference lines respectively. This preliminary preparation allows the decoder to quickly select the appropriate list without performing complex calculations during decoding, maintaining coding efficiency while simplifying the actual decoding process
Solution Approach 2:
The patent changes the parameters of the MPM lists based on the reference line index. The first MPM list is configured for zero reference lines with specific angular intra prediction modes, while the second MPM list is configured for non-zero reference lines with different modes. This parameter adaptation optimizes coding efficiency for each case without requiring a fully complex general solution
Data Source
AI summary
A method of signaling an intra prediction mode used to encode a current block in an encoded video bitstream using at least one processor includes generating a first most probable mode (MPM) list corresponding to a zero reference line of the current block, wherein the first MPM list includes a plurality of angular intra prediction modes; generating a second MPM list corresponding to one or more non-zero reference lines of the current block, wherein the second MPM list includes the plurality of angular intra prediction modes; signaling a reference line index indicating a reference line used to encode the current block from among the zero reference line and the one or more non-zero reference lines; and signaling an intra mode index indicating the intra prediction mode within the first MPM list or the second MPM list.