MPM List Intra Prediction with Multi-Reference Lines for Video Compression
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Solution Overview
Problem
The increasing demand for high-resolution, high-quality images and videos, particularly in virtual reality and augmented reality, necessitates a more efficient image/video compression technique to reduce transmission and storage costs.
Innovation Solution
An intra prediction method based on a Most Probable Mode (MPM) list, utilizing multi-reference line (MRL) index information and planar flag information to determine the intra prediction mode for image blocks, with context index increments based on Intra Sub Partition (ISP) mode application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional intra prediction methods are used for high-resolution images, then image quality can be maintained, but transmission and storage costs increase significantly
Solution Approach 1:
The patent changes the parameters of intra prediction by introducing MPM list-based mode selection, multi-reference line indexing, and planar mode flags. These parameter changes enable more accurate prediction modes to be selected adaptively, improving compression efficiency while maintaining image quality for high-resolution content
Solution Approach 2:
The patent implements dynamic intra prediction by constructing MPM lists adaptively based on neighboring block modes and using context-adaptive binary arithmetic coding (CABAC) with dynamic context index updates. This dynamic approach allows the system to adjust prediction parameters based on local image characteristics, achieving better compression without sacrificing quality
2Measurement precision
If detailed intra prediction modes are used for all blocks, then prediction accuracy improves, but signaling overhead and processing complexity increase
Solution Approach 1:
The patent segments the intra prediction process into multiple stages: first constructing an MPM list with the most likely modes, then using flags and indices to select from this segmented list. This segmentation reduces the number of bits needed for signaling compared to transmitting full mode information for all blocks
Solution Approach 2:
The patent applies partial action by using planar mode flags and MPM indices only when necessary, rather than explicitly signaling all prediction parameters for every block. The context-adaptive coding further reduces overhead by exploiting statistical dependencies, achieving high prediction accuracy with reduced signaling complexity
3Measurement precision
If planar flag information is signaled for all blocks, then intra prediction mode determination becomes more accurate, but bitstream overhead increases
Solution Approach 1:
The patent uses partial action by signaling planar flags and MPM indices only when needed, rather than for all blocks. The context-adaptive binary arithmetic coding further optimizes this by adapting probability models to the actual data statistics, reducing the expected bit cost while maintaining accurate mode determination where necessary
4Productivity
If MPM list-based intra prediction with multi-reference line indexing is implemented, then compression efficiency improves, but decoding complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining the MPM list structure and multi-reference line configurations based on neighboring block information before actual prediction. This preliminary construction of prediction candidates and reference lines simplifies the decoding process while achieving high compression efficiency through adaptive mode selection
Data Source
AI summary
An image decoding method performed by a decoding apparatus according to the present disclosure comprises the steps of: obtaining intra prediction information including at least one of MPM flag information, MRL index information, and planner flag information from a bitstream; checking the MPM flag information; checking the MRL index information on the basis of a case where the MPM flag information indicates that the MRL index information is checked; checking the planner flag information on the basis of a case where a value of the MRL index information is 0; deriving an intra prediction mode for a current block on the basis of the check for the planner flag information; deriving prediction samples for the current block on the basis of the intra prediction mode for the current block; and generating a reconstructed picture on the basis of the prediction samples.