Adaptive Angle Mode Coefficient Scanning for Wide Angular Intra Prediction
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Solution Overview
Problem
Current video coding technologies, such as HEVC and VVC, have limitations in intra prediction modes, particularly in capturing wide angular directions, which can lead to inefficient coefficient scanning methods that do not accurately represent the directionality of video data.
Innovation Solution
A method and apparatus for controlling intra prediction in video sequences by obtaining an index of an intra prediction mode, determining the coefficient scanning direction using a look-up table that maps intra prediction modes to scanning directions, and performing coefficient scanning based on this direction, specifically considering wide angle modes to adapt scanning methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional intra prediction modes are used, then the prediction directions are limited to 45 degrees or less, but the accuracy of capturing wide angular directions is poor
Solution Approach 1:
The patent introduces adaptive angle mode that dynamically adjusts the prediction angle based on the scanning direction. The encoder can switch between conventional modes and adaptive angle modes depending on the actual edge direction in the image, allowing the system to adapt to different angular requirements without being fixed to a limited set of predetermined angles
Solution Approach 2:
The patent changes the prediction angle parameter from fixed conventional values to variable values that can represent wide angular directions. By modifying the angle parameter in the prediction mode, the system can accurately capture edges at various angles including wide angles beyond the conventional 45-degree limit
2Productivity
If fixed coefficient scanning methods are used, then the scanning process is simple, but the efficiency of encoding wide angle modes is reduced
Solution Approach 1:
The patent makes the coefficient scanning process adaptive by selecting different scanning orders based on the prediction mode. For adaptive angle modes, the scanning direction is adjusted to match the prediction angle, optimizing the encoding efficiency for wide angular directions while maintaining simplicity for conventional modes
Solution Approach 2:
The scanning order parameter is changed based on the prediction mode being processed. The system dynamically selects between horizontal scan, vertical scan, or diagonal scan orders depending on whether the mode is conventional or adaptive angle, thereby optimizing encoding efficiency without requiring a completely new scanning mechanism
3Adaptability or versatility
If multiple intra prediction modes are supported, then the versatility of the system is improved, but the complexity of mode management increases
Solution Approach 1:
The patent segments the intra prediction modes into two distinct categories: conventional modes and adaptive angle modes. This segmentation allows the system to manage different mode types with different characteristics, simplifying the overall mode management by organizing modes into clear categories rather than treating them uniformly
Solution Approach 2:
The patent introduces an intermediary mechanism (the adaptive angle mode structure) that bridges conventional prediction modes and wide angular requirements. This intermediary layer allows the system to handle both conventional and advanced prediction needs through a unified framework, reducing the complexity of managing multiple mode types
Data Source
AI summary
A method of controlling intra prediction for decoding or encoding of a video sequence, is by at least one processor and includes obtaining an index of an intra prediction mode of a current block of the video sequence, obtaining a coefficient scanning direction based on the obtained index, using a first look up table indicating a mapping between a plurality of indices of a plurality of intra prediction modes and respective coefficient scanning directions, and performing a coefficient scanning of the current block, based on the obtained coefficient scanning direction.