Video Decoder Context Sharing for Lower CABAC Model Storage
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Solution Overview
Problem
Existing video coding technologies struggle to further compress video data without sacrificing picture quality, leading to a significant burden on communications networks and data storage.
Innovation Solution
A video decoding method that shares a context model for syntax elements in a block, reducing the need for multiple context models and minimizing storage space in decoders by using a single context model for syntax elements 1 and 2, and optionally using a preset context model set with 2 or 3 context models to determine context indices based on neighboring block values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple context models are used for different syntax elements, then decoding accuracy is improved, but storage space requirement increases
Solution Approach 1:
The patent merges the context models for syntax element 1 and syntax element 2 into a single shared context model. This is achieved by using the same context index for both syntax elements, allowing the decoder to use one context model structure to handle both types of syntax elements, thereby reducing storage space while maintaining decoding functionality.
Solution Approach 2:
The single shared context model is designed to serve multiple purposes by handling both syntax element 1 and syntax element 2 through the same context index mechanism. This universal approach allows the context model to be reused for different syntax elements, reducing the total number of context models needed while preserving decoding accuracy for both element types.
2Reliability
If multiple context models are stored for different syntax elements, then decoding reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines the management of multiple context models into a single context model structure. By using a unified context index that can refer to the same context model for both syntax element 1 and syntax element 2, the decoder's complexity is reduced while still maintaining the ability to accurately decode both syntax elements through the shared context.
Solution Approach 2:
Instead of storing separate context models for each syntax element, the patent uses a single context model that is referenced (copied) for both syntax element 1 and syntax element 2. This referencing approach maintains decoding reliability by using the same context logic for both elements while avoiding the complexity of managing multiple separate context model instances.
Data Source
AI summary
A video decoding method includes obtaining a to-be-entropy-decoded syntax element in a current block by parsing a received bitstream, where the to-be-entropy-decoded syntax element includes a syntax element 1 or a syntax element 2 in the current block, obtaining a context model corresponding to the to-be-entropy-decoded syntax element, where both of a context model corresponding to the syntax element 1 and a context model corresponding to the syntax element 2 are determined from the same preset context model set, entropy decoding the to-be-entropy-decoded syntax element based on the context model corresponding to the to-be-entropy-decoded syntax element, and obtaining a reconstructed image of the current block based on the syntax element obtained by entropy decoding.