CCLM Parameter Inheritance for Lower-Overhead Video Coding
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Solution Overview
Problem
The existing video coding standards, such as VVC, require additional signaling of information for cross-component linear model (CCLM) modes, which can increase complexity and overhead, necessitating improved techniques for efficient signaling of CCLM-related information.
Innovation Solution
A method and apparatus for video coding that involves determining an inherited model parameter set from a previously coded block in a CCLM mode, updating it if necessary, and using this updated model for decoding or encoding subsequent blocks, thereby reducing the need for explicit signaling of model parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CCLM modes are used to improve coding efficiency, then prediction accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent applies preliminary action by deriving and storing model parameters from previously coded blocks before they are needed for current block prediction. The inheritance mechanism pre-computes parameters from neighboring blocks, so when CCLM mode is selected for the current block, the parameters are already available without requiring fresh derivation or extensive signaling.
Solution Approach 2:
The patent uses copying by inheriting model parameters from previously coded neighboring blocks instead of deriving them de novo for each block. The decoder copies parameters from neighboring blocks (e.g., left, above blocks) and applies them to the current block, significantly reducing the need to signal these parameters in the bitstream.
2Measurement precision
If model parameters are explicitly signaled for each block, then prediction precision is improved, but bitstream overhead increases
Solution Approach 1:
The patent performs preliminary derivation of model parameters from previously coded blocks and stores them in memory before they are needed. This pre-computation allows the decoder to retrieve and use these parameters without requiring them to be explicitly signaled in the bitstream for each block, thus reducing overhead while maintaining precision.
Solution Approach 2:
The patent implements self-service by enabling the decoder to autonomously derive model parameters from previously decoded neighboring blocks without requiring explicit signaling from the encoder. The inheritance mechanism allows the decoder to self-generate the necessary parameters, eliminating the need for additional bitstream information.
3Loss of information
If CCLM parameters are inherited from previous blocks, then signaling overhead is reduced, but parameter accuracy may deteriorate
Solution Approach 1:
The patent applies preliminary action by pre-deriving model parameters from previously coded blocks and storing them for inheritance. This pre-computation ensures that accurate parameters are available before they are needed, maintaining precision while reducing the need for re-signaling.
Solution Approach 2:
The patent uses feedback by continuously updating the inherited parameters based on previously coded blocks. The decoder maintains a buffer of recently decoded blocks and uses the most relevant neighboring blocks to derive parameters, ensuring that the inherited parameters remain accurate and adaptive to local variations in the video content.
Data Source
AI summary
A method and apparatus for video coding are disclosed. According to the method for the decoder side, encoded data associated with a current block comprising a first-colour block and a second-colour block are received. An inherited model parameter set is determined from a previously coded block coded in a first CCLM related mode, wherein the inherited model parameter set comprises a first scaling parameter associated with the first CCLM related mode. A final inherited model parameter set is derived if an update value for the inherited model parameter set is determined, where the final inherited model parameter set is determined based on the first scaling parameter and the update value. Then, the encoded data associated with the second-colour block are decoded using prediction data based on an updated CCLM related model associated with the final inherited model parameter set. A method and apparatus for the encoder side are also disclosed.