Unified Intra Prediction Mode Coding for Video Compression
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Solution Overview
Problem
Existing video coding systems, such as HEVC, have increased system complexity due to the use of different sets of Intra prediction modes for 4×4 and larger prediction units, which can be inefficient and require non-uniform code lengths for remaining modes, leading to increased bit requirements and operational complexity.
Innovation Solution
Unifying Intra prediction modes across different block sizes, including 4×4, 8×8, 16×16, 32×32, and 64×64 prediction units, and reducing the number of modes by removing specific modes like 18, 34, or 26, allowing for predictive coding using 5-bit fixed length codes for the remaining modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If different sets of Intra prediction modes are used for 4×4 and larger prediction units, then prediction accuracy is improved, but system complexity increases
Solution Approach 1:
The patent merges the separate Intra prediction mode sets for 4×4 and larger prediction units into a single unified set. By combining the 18 modes for 4×4 PUs and 35 modes for larger PUs into one shared mode set, the patent reduces system complexity while maintaining the ability to achieve accurate predictions through selective mode application.
Solution Approach 2:
The patent creates a universal Intra prediction mode set that serves multiple prediction unit sizes simultaneously. This multi-functional mode set can be applied to 4×4, 8×8, 16×16, and other larger PUs, eliminating the need for separate mode definitions and reducing overall system complexity.
2Measurement precision
If different sets of Intra prediction modes are used for 4×4 and larger prediction units, then prediction accuracy is improved, but bit requirements increase
Solution Approach 1:
By merging the mode sets and using a unified Intra prediction mode indexing system, the patent reduces the total number of bits required to signal prediction modes. The unified approach allows for more efficient coding of mode information across different prediction unit sizes.
3Measurement precision
If different sets of Intra prediction modes are used for 4×4 and larger prediction units, then prediction accuracy is improved, but operational complexity increases
Solution Approach 1:
The patent combines the operational procedures for different Intra prediction mode sets into a single unified process. This eliminates the need for separate handling logic for 4×4 and larger PUs, simplifying the operational complexity while preserving prediction accuracy through the unified mode selection and application process.
4Device complexity
If the number of Intra prediction modes is reduced by removing specific modes, then system complexity is reduced, but prediction accuracy may deteriorate
Solution Approach 1:
The patent extracts and removes specific redundant Intra prediction modes (modes 18, 34, or 26) from the unified mode set. This extraction process reduces system complexity by decreasing the total number of modes from 35 to 32, while the remaining modes are sufficient to maintain prediction accuracy for various prediction unit sizes.
Solution Approach 2:
The patent changes the parameter of mode count from 35 to 32 by removing specific modes. This parameter change reduces the complexity of the prediction mode system while the selected removal patterns ensure that essential prediction directions are preserved, maintaining overall prediction accuracy.
Data Source
AI summary
According to at least one aspect, a method for predictive Intra coding is provided. The method comprises: determining a set of Intra prediction modes used for prediction unit (PU) blocks with a plurality of different block sizes comprising a 4×4 block size and at least two other block sizes; applying predictive Intra coding to a first PU block having a first block size that matches a block size in the plurality of different block sizes based on one or more neighboring PU blocks according to a first Intra prediction mode selected from the set of Intra prediction modes; and applying predictive Intra coding to a second PU block having a second block size that is different from the first block size and matches a block size in the plurality of different block sizes according to a second Intra prediction mode selected from the set of Intra prediction modes.