Restricted Sub-PU Prediction in 3D Video Coding
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Solution Overview
Problem
Current three-dimensional video coding systems face high memory bandwidth requirements due to small sub-PU sizes, which are not efficiently addressed by existing technologies like 3D-HEVC, leading to increased system memory bandwidth issues.
Innovation Solution
Implementing restricted sub-PU level prediction by disabling bi-prediction for sub-PUs smaller than a minimum size (e.g., 8×8) and restricting partitioning based on specific criteria, such as asymmetric motion partition modes, to reduce memory bandwidth while maintaining system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sub-PU level prediction is applied to small PUs, then prediction accuracy is improved, but memory bandwidth requirement increases
Solution Approach 1:
The patent divides a PU into multiple sub-PUs to enable sub-PU level prediction, which improves prediction accuracy by capturing local variations. However, this segmentation increases memory bandwidth requirements. The patent resolves this by selectively applying sub-PU level prediction only when beneficial, rather than universally to all PUs.
Solution Approach 2:
The patent introduces a threshold parameter (minimum PU size) that controls when sub-PU level prediction is applied. By changing this parameter, the system can adapt between high accuracy mode (lower threshold) and low memory bandwidth mode (higher threshold), resolving the contradiction between prediction accuracy and memory bandwidth requirements.
2Measurement precision
If bi-prediction is enabled for small sub-PU sizes, then prediction performance is improved, but system memory bandwidth increases
Solution Approach 1:
The patent applies different prediction strategies to different regions based on PU size. For small sub-PU sizes, bi-prediction is disabled to reduce memory bandwidth, while for larger PUs, bi-prediction remains enabled to maintain prediction performance. This local differentiation resolves the contradiction by optimizing each region according to its specific characteristics.
3Measurement precision
If sub-PU size is reduced, then prediction precision is improved, but device complexity increases
Solution Approach 1:
The patent applies sub-PU level prediction partially rather than universally. By setting a minimum size threshold, sub-PU level processing is applied only to PUs that meet the criteria, avoiding the complexity overhead for PUs where it would not provide significant benefit. This partial application resolves the contradiction between precision improvement and device complexity.
Data Source
AI summary
A method for a three-dimensional encoding or decoding system incorporating restricted sub-PU level prediction is disclosed. In one embodiment, the sub-PU level prediction associated with inter-view motion prediction or view synthesis prediction is restricted to the uni-prediction. In another embodiment, the sub-PU partition associated with inter-view motion prediction or view synthesis prediction is disabled if the sub-PU partition would result in sub-PU size smaller than the minimum PU split size or the PU belongs to a restricted partition group. The minimum PU split size may correspond to 8×8. The restricted partition group may correspond to one or more asymmetric motion partition (AMP) modes.