Chroma Intra Prediction Mode Segmentation for Video Coding
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Solution Overview
Problem
Existing video coding techniques force all chroma blocks in a coding unit to share the same chroma Intra prediction mode, which may not optimize coding performance due to differing characteristics among chroma blocks.
Innovation Solution
A method allowing different chroma blocks in a coding unit to use separate chroma Intra prediction modes, including Planar, DC, HOR, VER, Top+Left LM, Top-Only LM, Left-Only LM, DM, and PRE_DM modes, with syntax elements signaling these modes for improved coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If all chroma blocks in a coding unit share the same chroma Intra prediction mode, then device complexity is reduced and ease of operation is improved, but coding efficiency deteriorates and bitrate savings are limited
Solution Approach 1:
The patent divides the chroma blocks in a coding unit into multiple groups (first chroma blocks and second chroma blocks) that can be independently assigned different Intra prediction modes. This segmentation allows each group to use the most suitable prediction mode (Planar, DC, HOR, VER, or LM) based on its specific characteristics, thereby improving coding efficiency without significantly increasing overall system complexity.
Solution Approach 2:
The patent applies different prediction modes to different regions (chroma block groups) based on their local characteristics. By allowing separate mode selection for first and second chroma blocks, the system optimizes prediction quality locally for each group while maintaining manageable overall complexity through structured mode assignment.
2Productivity
If separate chroma Intra prediction modes are allowed for different chroma blocks, then coding efficiency is improved with bitrate savings of over 1%, but device complexity increases
Solution Approach 1:
The patent segments chroma blocks into first and second groups that can independently use different prediction modes. This segmentation enables the system to achieve over 1% bitrate savings by optimizing prediction for each group separately, while the segmented structure itself provides a manageable framework that limits the increase in overall device complexity.
Solution Approach 2:
The patent introduces dynamic mode selection where the prediction mode for chroma blocks can vary based on coding conditions. The system dynamically assigns Planar, DC, HOR, VER, or LM modes to different chroma block groups, allowing flexibility to achieve bitrate savings while adapting to different content characteristics without requiring a completely complex system redesign.
3Adaptability or versatility
If multiple chroma Intra prediction modes are implemented, then adaptability to different chroma block characteristics is improved, but ease of operation deteriorates due to increased mode selection complexity
Solution Approach 1:
The patent segments chroma blocks into first and second groups with distinct mode selection rules. This segmentation improves adaptability by allowing different prediction modes (Planar, DC, HOR, VER, LM) to be applied to different groups based on their characteristics, while the clear group division simplifies the operational complexity by providing a structured approach to mode selection.
Solution Approach 2:
The patent changes the parameter of prediction mode adaptability by introducing multiple modes (Planar, DC, HOR, VER, LM) that can be selectively applied to different chroma block groups. This parameter change enhances versatility to handle diverse chroma characteristics while the systematic parameter assignment framework maintains operational ease through consistent selection rules.
Data Source
AI summary
A method for chroma Intra prediction allowing different chroma blocks in a coding unit to use separate chroma Intra prediction modes is disclosed. The method selects chroma Intra prediction modes for a first chroma block and one or more non-first chroma blocks in a current color block, where the first chroma block and at least one non-first chroma block use separate chroma Intra prediction modes. The method may comprise determining candidate mode sets for the first chroma block and the non-first chroma blocks. The method may also comprise signaling information of the chroma Intra prediction modes selected for the first chroma block and said one or more non-first chroma blocks. Furthermore, a method of chroma Intra prediction using one or more cross-chroma linear model Intra prediction modes is disclosed for improving coding efficiency of chroma Intra prediction.