Chroma Intra Mode List Using Collocated Luma Prediction
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Solution Overview
Problem
Existing video coding methods do not effectively utilize the correlation between luma and chroma blocks for improved chroma prediction, leading to inefficiencies in compression and potential quality degradation.
Innovation Solution
Populate the chroma mode list by incorporating directional intra prediction modes from collocated luma blocks and neighboring blocks, placing them at the beginning of the list to enhance prediction accuracy without increasing overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the chroma mode list is populated using traditional methods without utilizing luma-chroma correlation, then the overhead remains minimal, but the prediction accuracy for chroma blocks deteriorates
Solution Approach 1:
The chroma mode list leverages information already present in the luma block prediction modes to populate itself, making the system self-sufficient. By using the collocated luma block's intra prediction mode to directly determine chroma prediction modes, the method eliminates the need for separate chroma mode signaling while improving prediction accuracy through the inherent luma-chroma correlation.
Solution Approach 2:
The luma block's intra prediction mode serves multiple functions: it not only predicts the luma block itself but also provides the prediction modes for the associated chroma blocks. This multi-functionality allows the same data (luma prediction mode) to benefit both luma and chroma components, reducing overall overhead while improving chroma prediction.
2Measurement precision
If directional intra prediction modes from collocated luma blocks are placed at the beginning of the chroma mode list, then prediction accuracy improves, but the complexity of mode list management increases
Solution Approach 1:
The chroma mode list is pre-populated with directional intra prediction modes derived from the collocated luma block before the actual chroma prediction process. By performing this preparation in advance and organizing modes in a predetermined order (with directional modes from luma blocks at the beginning), the decoder can efficiently access the most relevant modes without complex real-time calculations.
Solution Approach 2:
The method changes the organizational parameter of the chroma mode list by prioritizing directional intra prediction modes at the beginning of the list. This reordering based on the collocated luma block's mode creates a more efficient search order, allowing the decoder to try the most probable modes first, thereby improving prediction accuracy while maintaining a simple fixed-length list structure.
3Loss of information
If the chroma mode list maintains a fixed length, then the overhead is controlled, but the ability to accommodate additional prediction modes is limited
Solution Approach 1:
The method extracts only the essential directional intra prediction modes from the collocated luma block and places them at the beginning of the fixed-length chroma mode list. By selecting and extracting only the most relevant modes rather than including all possible modes, the system maintains a compact fixed-length list while still capturing the important luma-chroma correlation for improved prediction.
Data Source
AI summary
The various implementations described herein include methods and systems for coding video. In one aspect, a method includes receiving a video bitstream comprising a plurality of blocks, including a chroma block. The method includes identifying a set of intra prediction modes for one or more luma positions collocated with the chroma block. The method includes populating a chroma mode list based on the set of intra prediction modes. The method also includes reconstructing the chroma block using a prediction mode from the chroma mode list.