Directional Intra-Prediction Mode Removal for Rectangular Video Blocks
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Solution Overview
Problem
Current video coding standards, such as ITU-T H.265/HEVC, face inefficiencies in handling rectangular video coding blocks due to an asymmetrical nature that does not account for the aspect ratio or availability of reference samples, leading to increased computational complexity and signaling overhead.
Innovation Solution
The proposed solution involves an apparatus and method that dynamically adjusts the set of directional intra-prediction modes based on the aspect ratio and availability of reference samples for rectangular video coding blocks, using a reference sample determining unit to select and remove modes, and an intra-prediction unit to intra-predict pixel values with a reduced set of modes, thereby optimizing coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a full set of directional intra-prediction modes is used for rectangular video coding blocks, then prediction accuracy is improved, but computational complexity and signaling overhead increase
Solution Approach 1:
The patent applies local quality by adapting the set of directional intra-prediction modes to the specific aspect ratio and reference sample availability of each rectangular video coding block. Instead of using a uniform full set of modes for all blocks, the system selectively enables only those modes that are appropriate for the local characteristics of each block, thereby maintaining prediction accuracy where needed while reducing computational complexity for blocks where certain modes are not applicable.
Solution Approach 2:
The patent implements dynamics by making the set of directional intra-prediction modes adaptive rather than static. The available prediction modes are dynamically adjusted based on the aspect ratio and reference sample availability of each rectangular video coding block. This dynamic adaptation allows the system to optimize the balance between prediction accuracy and computational complexity for each specific block configuration.
2Adaptability or versatility
If all directional intra-prediction modes are supported for rectangular blocks, then coding flexibility is improved, but signaling overhead increases
Solution Approach 1:
The patent reduces signaling overhead by applying local quality - different signaling approaches are used based on the specific characteristics of each rectangular video coding block. For blocks where certain directional modes are not applicable due to aspect ratio constraints or reference sample availability, the signaling for those modes is omitted, thereby reducing the overall signaling overhead while maintaining coding flexibility for the applicable modes.
3Ease of manufacture
If the asymmetrical nature of rectangular blocks is not considered, then implementation simplicity is maintained, but coding efficiency decreases
Solution Approach 1:
The patent explicitly addresses the asymmetrical nature of rectangular video coding blocks by introducing asymmetry into the prediction mode selection process. The system considers the aspect ratio and reference sample availability specific to each rectangular block configuration, enabling more efficient prediction for asymmetric blocks while maintaining reasonable implementation complexity through systematic rules for mode selection and removal.
Data Source
AI summary
An intra-prediction method includes: determining, by an intra-prediction apparatus, a directional intra-prediction mode for a rectangular video coding block from an extended set of directional intra-prediction modes, wherein the extended set of directional intra-prediction modes includes extended directional intra-prediction modes and conventional directional intra-prediction modes and determining, by the intra-prediction apparatus, a plurality of available reference samples based on a direction of the directional intra-prediction mode. The method further includes: intra-predicting, by the intra-prediction apparatus, pixel values of pixels of the rectangular video coding block based on the plurality of available reference samples.