Video Chroma Prediction Using Target Block Vectors for IBC
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Solution Overview
Problem
In video encoding, the use of Intra Block Copy (IBC) mode for luma blocks results in inaccurate chroma prediction due to unreasonable setting of chroma prediction modes, leading to reduced coding efficiency.
Innovation Solution
The method involves determining a target Block Vector (BV) parameter and a symmetric relationship for a current block, predicting a second color component based on this parameter, and using a reconstructed value to improve chroma prediction accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If IBC mode is used for luma block with default chroma prediction mode, then encoding complexity is reduced, but chroma prediction accuracy deteriorates
Solution Approach 1:
The patent changes the chroma prediction mode parameter based on the luma prediction mode. When IBC mode is detected for the luma block, the chroma prediction mode is automatically set to match the luma mode, rather than using a default mode. This parameter adaptation resolves the contradiction by maintaining low complexity (through automatic mode selection) while improving chroma prediction accuracy (through mode matching).
Solution Approach 2:
The patent makes the chroma prediction mechanism universal by allowing it to adapt to different luma prediction modes. The chroma prediction system can now function effectively with both IBC and non-IBC luma modes, improving overall system versatility and accuracy without significantly increasing complexity.
2Measurement precision
If chroma prediction mode is set to match luma IBC mode, then chroma prediction accuracy is improved, but coding efficiency may be reduced due to additional mode signaling
Solution Approach 1:
The patent applies partial action by only adjusting the chroma prediction mode when the luma block uses IBC mode. For other luma modes, the default chroma prediction behavior is maintained. This selective approach improves chroma accuracy where needed (IBC modes) while avoiding unnecessary complexity and signaling overhead in other cases, thus preserving overall coding efficiency.
3Ease of operation
If traditional chroma prediction is used without considering luma prediction mode, then encoding process is simpler, but prediction performance deteriorates
Solution Approach 1:
The patent performs preliminary action by detecting the luma prediction mode before setting the chroma prediction mode. This advance detection and automatic configuration simplifies the encoding process (maintaining ease of operation) while ensuring optimal chroma prediction performance (improving reliability) through proactive mode matching.
Data Source
AI summary
Disclosed in the embodiments of the present application are an encoding method, a decoding method and a storage medium. The decoding method includes: determining a first color component block of the current block; when a prediction mode of the first color component block meets a first condition, determining a target block vector parameter of the current block, and determining a target symmetric relation according to the target block vector parameter of the current block; performing prediction processing on a second color component of the current block according to the target block vector parameter, so as to determine a predicted value of the second color component of the current block; and determining a reconstructed value of the second color component of the current block according to the predicted value of the second color component of the current block and the target symmetric relation.